Sealing of Abandoned Areas, 28796-28817 [07-2535]
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Federal Register / Vol. 72, No. 98 / Tuesday, May 22, 2007 / Rules and Regulations
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ADDRESSES:
DEPARTMENT OF LABOR
Mine Safety and Health Administration
30 CFR Part 75
RIN 1219–AB52
Sealing of Abandoned Areas
Mine Safety and Health
Administration (MSHA), Labor.
ACTION: Emergency temporary standard;
Notice of public hearings; Notice of
close of comment period.
AGENCY:
SUMMARY: The Mine Safety and Health
Administration (MSHA) is issuing an
emergency temporary standard (ETS)
under section 101(b) of the Federal
Mine Safety and Health Act of 1977 in
response to the grave danger that miners
face when underground seals separating
abandoned areas from active workings
fail. MSHA has concluded from its
investigations of mine explosions that
occurred and other recent reports, that
additional immediate action is
necessary to protect miners. This ETS
includes requirements to strengthen the
design, the construction, the
maintenance, and the repair of seals, as
well as requirements for sampling and
controlling atmospheres behind seals. It
also increases the level of overpressure
for new seals, thus implementing the
requirements of the Mine Improvement
and New Emergency Response (MINER)
Act of 2006.
DATES: This emergency temporary
standard is effective May 22, 2007. This
standard must be replaced with a final
rule within 9 months. MSHA will hold
public hearings on July 10, 2007, July
12, 2007, July 17, 2007 and July 19,
2007 at the locations listed in the Public
Hearings section below under the
SUPPLEMENTARY INFORMATION section of
this document. If individuals or
organizations wish to make an oral
presentation for the record, the Mine
Safety and Health Administration
(MSHA) is asking that you submit your
request at least 5 days prior to the
hearing dates. The comment period will
close on July 6, 2007.
Date
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July
July
July
July
10,
12,
17,
19,
2007
2007
2007
2007
The
outline of this ETS is as follows:
SUPPLEMENTARY INFORMATION:
I. Public Hearings
II. Introduction
III. Basis for the Emergency Temporary
Standard
A. Regulatory Authority
B. Grave Danger
IV. Discussion of the Emergency Temporary
Standard
A. Background
B. General Discussion
C. Section-by-Section Analysis
V. Executive Order 12866
A. Population-at-Risk
B. Benefits
C. Compliance Costs
VI. Feasibility
A. Technological Feasibility
B. Economic Feasibility
VII. Regulatory Flexibility Act and Small
Business Regulatory Enforcement
Fairness Act (SBREFA)
A. Definition of a Small Mine
B. Factual Basis for Certification
VIII. Paperwork Reduction Act of 1995
A. Summary
B. Details
IX. Other Regulatory Considerations
X. References
XI. Emergency Temporary Standard—
Regulatory text
I. Public Hearings
MSHA will hold four public hearings
on the ETS. The public hearings will
begin at 9 a.m. and end after the last
speaker speaks, and in any event not
later than 5 p.m., on the following dates
at the locations indicated:
Location
.............
.............
.............
.............
Phone
Lakeview Golf Resort and Spa, One Lakeview Drive, Morgantown, WV 26508 .....................................
Crowne Plaza Hotel, 1375 South Broadway, Lexington, KY 40504 ........................................................
Embassy Suites Denver, 7525 East Hampden Avenue, Denver, CO 80231 ..........................................
Sheraton Birmingham Hotel, 2101 Richard Arrington Jr. Boulevard North, Birmingham, AL 35203 ......
800–624–8300
859–255–4281
303–696–6644
205–324–5000
The hearings will begin with an
opening statement from MSHA,
followed by an opportunity for members
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electronically to zzMSHAComments@dol.gov, by facsimile to
(202) 693–9441, or by regular mail, hand
delivery, or courier to MSHA, Office of
Standards, Regulations, and Variances,
1100 Wilson Blvd., Room 2350,
Arlington, Virginia 22209–3939.
Hearings: Locations of the public
hearings are in the SUPPLEMENTARY
INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT:
Patricia W. Silvey, Director, Office of
Standards, Regulations, and Variances,
MSHA, 1100 Wilson Blvd, Room 2350,
Arlington, Virginia 22209–3939,
silvey.patricia@dol.gov (e-mail), (202)
693–9440 (voice), or (202) 693–9441.
(telefax).
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of the public to make oral presentations.
You do not have to make a written
request to speak. Speakers will speak in
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the order that they sign in. Any
unallotted time will be made available
for persons making same-day requests.
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Federal Register / Vol. 72, No. 98 / Tuesday, May 22, 2007 / Rules and Regulations
At the discretion of the presiding
official, the time allocated to speakers
for their presentation may be limited.
Speakers and other attendees may also
present information to the MSHA panel
for inclusion in the rulemaking record.
The hearings will be conducted in an
informal manner. The hearing panel
may ask questions of speakers. Although
formal rules of evidence or cross
examination will not apply, the
presiding official may exercise
discretion to ensure the orderly progress
of the hearing and may exclude
irrelevant or unduly repetitious material
and questions. A verbatim transcript of
the proceedings will be prepared and
made a part of the rulemaking record.
Copies of the transcript will be available
to the public. The transcript will also be
available on MSHA’s Home Page at
https://www.msha.gov, under Statutory
and Regulatory Information.
MSHA will accept post-hearing
written comments and other appropriate
data for the record from any interested
party, including those not presenting
oral statements. Written comments will
be included in the rulemaking record.
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II. Introduction
This ETS is issued under section
101(b) of the Federal Mine Safety and
Health Act of 1977 (Mine Act) as
amended by the Mine Improvement and
New Emergency Response Act of 2006
(MINER Act), 30 U.S.C. 811(b). The ETS
establishes or revises standards in part
75—subpart D—Ventilation. These new
standards strengthen the design,
construction, maintenance, and repair of
seals and monitoring and control of
atmospheres behind seals in order to
reduce the risk of seal failure and the
risk of explosions in abandoned areas of
underground coal mines.
In accordance with section 101(b)(3)
of the Mine Act, an Emergency
Temporary Standard (ETS) serves as
both a final rule with immediate effect
and a proposed rule to establish a final
rule through the notice and comment
process. Therefore, the final rule may
differ from an ETS just as any final rule
may differ from a proposed rule. The
Mine Act states that the ETS is a
temporary standard and must be
superseded by a final rule within nine
months. The Legislative History of the
Mine Act reinforces the statutory
language regarding the ETS serving as a
proposed rule ‘‘so that all views can be
carefully considered in connection with
the issuance of a permanent standard.’’
S. Rept. 181, 95th Cong., 1st Sess. 24
(1977).
The preamble discusses specific
provisions that may be included in the
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final rule and MSHA solicits comments
on these provisions.
III. Basis for the Emergency Temporary
Standard
A. Regulatory Authority
Section 101(b) of the Mine Act
provides that:
1. The Secretary shall provide,
without regard to the requirements of
chapter 5, title 5, United States Code, for
an emergency temporary mandatory
health or safety standard to take
immediate effect upon publication in
the Federal Register if [s]he determines
(A) that miners are exposed to grave
danger from exposure to substances or
agents determined to be toxic or
physically harmful, or to other hazards,
and (B) that such emergency standard is
necessary to protect miners from such
danger.
2. A temporary mandatory health or
safety standard shall be effective until
superseded by a mandatory standard
promulgated in accordance with the
procedures prescribed in paragraph (3)
of this subsection.
3. Upon publication of such standard
in the Federal Register, the Secretary
shall commence a proceeding in accord
with section 101(a) [involving notice
and comment], and the standards as
published shall also serve as a proposed
rule for the proceeding. The Secretary
shall promulgate a mandatory health or
safety standard under this paragraph no
later than nine months after publication
of the emergency temporary standard as
provided in paragraph (2).
An ETS is an extraordinary measure
provided by the Mine Act to enable
MSHA ‘‘to react quickly to grave
dangers that threaten miners before
those dangers manifest themselves in
serious or fatal injuries or illnesses.’’ S.
Rept. 181, 95th Cong., 1st Sess. 23
(1977). Additionally, ‘‘* * * once the
Secretary has identified a grave danger
that threatens miners the Committee
expects the Secretary to issue an
emergency temporary standard as
quickly as possible, not necessarily
waiting until [she] can investigate how
well that grave danger is being managed
or controlled in particular mines.’’
Senate Report at 24. An ETS takes effect
upon publication in the Federal
Register, and is a fully enforceable
standard.
To assure the comprehensive
protection of miners, the ETS authority
applies to all types of grave dangers
without qualification. The legislative
history of the Mine Act emphasizes that
‘‘to exclude any kind of grave danger
would contradict the basic purpose of
emergency temporary standards
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protecting miners from grave dangers.’’
S. Rept. 181, 95th Cong., 1st Sess., 24
(1977). The ETS authority thus covers
dangers arising from exposure to toxic
or physically harmful substances or
agents and to ‘‘other hazards.’’ It applies
to dangers longstanding or novel, to
dangers that ‘‘result from conditions
whose harmful potential has just been
discovered’’ or to which large numbers
of miners are ‘‘newly exposed.’’ Id.
A record of fatalities or serious
injuries is not necessary before an ETS
can be issued because ‘‘[d]isasters,
fatalities, and disabilities are the very
thing this provision is designed to
prevent.’’ Id. at 23. At the same time, the
legislative history of the Mine Act is
clear that an ETS is not limited to new
dangers in the mining industry: ‘‘That a
danger has gone unremedied should not
be a bar to issuing an emergency
standard. Indeed, if such is the case the
need for prompt action is that much
more pressing.’’ Id. at 24.
When issuing an ETS, MSHA is ‘‘not
required to prove the existence of grave
danger as a matter of record evidence
prior to taking action.’’ Id. The
legislative history expressly recognizes
‘‘the need to act quickly where, in the
judgment of the Secretary, a grave
danger to miners exists.’’ Id. The ETS is
a critical statutory tool that MSHA can
use to take immediate action to prevent
the loss of life in the mines. MSHA
accordingly has employed an ETS
previously to order ‘‘hands-on’’ training
for miners in the use of self-contained
self-rescue (SCSR) devices 52 FR 24373
(June 30, 1987), to order certain training
and mine evacuation procedures for
underground coal mines 67 FR 76658
(December 12, 2002) and to order new
accident notification timeframes,
provide new safety equipment, training
and drills in mine emergency
evacuations 71 FR 12252, (March 9,
2006).
B. Grave Danger
Based on MSHA’s accident
investigation reports of the Sago and
Darby mine explosions,1 the National
Institute for Occupational Safety and
Health’s (NIOSH) reports on explosion
testing and modeling, MSHA’s in-mine
seal evaluations, and review of technical
literature, MSHA has determined that
new comprehensive standards for seal
design approval, strength and
installation approval, construction,
maintenance and repair, sampling and
monitoring, training and recordkeeping
1 MSHA Report of Investigation/Mine Explosion,
Sago Mine, January 2, 2006 and MSHA Report of
Investigation/Mine Explosion, Darby Mine Number
1, May 20, 2006. These reports can be found on
MSHA’s Web site at: https://www.msha.gov.
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Federal Register / Vol. 72, No. 98 / Tuesday, May 22, 2007 / Rules and Regulations
are necessary to immediately protect
miners from hazards of sealed areas.
Underground coal mines are dynamic
work environments in which the
working conditions can change rapidly.
Caved, mined-out areas may contain
coal dust and accumulated gas which
can be ignited by rock falls, lightning,
and in some instances, fires started by
spontaneous combustion. Seals are used
to isolate and contain this environment
of the active workings of the mine.
Adequate seals are crucial to prevent an
explosion from propagating to the outby
side of the seal where miners work or
travel. Seals must therefore be designed
to withstand elevated pressures and
contain explosions by preventing
potentially explosive or toxic gasses
from migrating into the active working
areas of underground coal mines.
Miners rely on seals to protect them
from the hazardous and sometimes
explosive environments within the
sealed area.
The existing safety standards for
construction of solid-concrete block
seals adopt specific construction
criteria. Existing requirements
addressing construction of seals using
equivalent alternative materials and
methods were established, as an interim
measure, in MSHA’s Program
Information Bulletin No. P06–16, ‘‘Use
of Alternative Seal Methods and
Materials Pursuant to 30 CFR
75.335(a)(2)),’’ issued on July 19, 2006
(July 2006 PIB). Under the July 2006
PIB, MSHA increased the strength
requirements for new alternative seals to
reliably withstand an overpressure of at
least 50 pounds per square inch gauge
(psig) in the conditions in which they
will be installed as demonstrated by
well-defined and certified engineering
designs. An alternative seal design
could also be approved based on actual
test results validating the psig. All seal
construction must be approved by the
District Manager in the mine’s
ventilation plan. To be considered for
approval, mine operators must have a
professional engineer (PE) who is
knowledgeable in structural engineering
to certify seal designs and supporting
data. In addition, the proposed
ventilation plan must provide that a
senior mine management official (such
as mine manager, superintendent, etc.)
certify that the construction,
installation, and materials used were in
accordance with the mine’s approved
ventilation plan. Furthermore, the July
2006 PIB requires an assessment of the
atmosphere behind existing alternative
seals to determine the potential for an
explosion and to assess seal integrity.
The July 2006 PIB requires the operator
to take remedial actions which may
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include inerting the sealed atmosphere,
increasing the capacity of the existing
seal to withstand at least 50 psig
overpressure, constructing an additional
alternative seal having this capacity, or
constructing a solid-concrete seal.
Finally, the July 2006 PIB requires that
high risk seals, (such as if failure could
adversely affect miners’ safety) and seals
with a poor performance history will
require additional actions to better
protect miners, including periodic
monitoring of the atmosphere behind
the seals.
MSHA determined in the Sago
accident that even though the seals were
not constructed as approved in the
ventilation plan, they still could
withstand an explosion overpressure of
21 psi. In the Agency’s root cause
analysis of the Sago accident, MSHA
found that: (1) The seals were not
capable of withstanding the forces
generated by the explosion; (2) The
atmosphere in the sealed area was not
monitored and it contained explosive
methane/air mixtures; (3) Lightning was
the most likely ignition source for the
explosion with the energy transferring
onto an abandoned pump cable in the
sealed area and providing an ignition
source for the explosion. MSHA found
that the explosive forces generated
behind the sealed area in the Sago
accident were at least 93 psi.
In the Darby accident, MSHA found
that the seals were improperly
constructed and had an inadequate
pressure rating. MSHA also concluded
that the use of an oxygen acetylene
cutting torch to cut a metal strap outby
a seal was the most likely ignition
source. MSHA further concluded that
when seals are improperly constructed,
they present a hazard to miners, even
when ignition sources are located outby
the seal.
When seals are improperly
constructed and maintained, air may
leak excessively through the seals,
which may result in explosive
conditions inby the seals. The air
leakage causes increased levels of
hazardous conditions whereby
introduction of ignition sources could
cause an explosion. Air leakage from the
sealed area to active working areas
could also contaminate the
atmospheres, resulting in miners being
exposed to potential explosions or toxic
gasses.
In addition, the ETS requires that
insulated cables and metallic objects
through or across seals be removed from
the area to be sealed, and prohibits
welding, cutting or soldering with an
arc or flame within 150 feet of a seal.
The July 2006 PIB’s interim action has
serious limitations in that it fails to
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provide comprehensive protection for
miners from the dangers of explosions
in sealed areas: it only permits testing
as one method of demonstrating seal
strength; it does not address explosion
forces generated behind a sealed area
that are greater than 50 psi; it requires
only a one-time assessment of the
atmosphere behind the seal rather than
a sampling plan approved by MSHA as
required under the ETS; although the
July 2006 PIB states that periodic
monitoring of sealed areas may be
required for high risk seals (such as if
failure could adversely affect miners’
safety), a periodic monitoring frequency
was not specified in the July 2006 PIB;
the July 2006 PIB does not address the
hazard of welding, cutting, and
soldering with an arc or flame in close
proximity to a seal. Therefore, hazards
in existing sealed areas present a grave
danger to miners.
The Secretary has therefore
determined that miners are exposed to
grave danger if existing and new seals
are not properly constructed,
maintained, monitored, and repaired in
accordance with this ETS.
In addition, for the above-stated
reasons under the Administrative
Procedure Act (APA), 5 U.S.C. 553(b)(B)
and (d)(3), MSHA finds good cause
exists to dispense with notice and
comment and make the ETS effective
immediately. To delay the effective date
of the ETS is contrary to the public
interest because any delay in the ETS
effective date further exposes miners to
grave danger from inadequately
designed, constructed, maintained, and
repaired seals.
IV. Discussion of the Emergency
Temporary Standard
A. Background
In the Federal Coal Mine Health and
Safety Act of 1969 (Coal Act), the
predecessor to the existing Mine Act,
Congress first recognized that mine
operators must seal abandoned and
isolated areas of underground coal
mines for the protection of miners’
safety:
In the case of mines opened on or after the
operative date of this title, or in the case of
areas developed on or after such date in
mines opened prior to such date, the mining
system shall be designed, in accordance with
a plan and revisions thereof approved by the
Secretary and adopted by the operator, so
that, as each set of cross entries, room entries,
or panel entries of the mine are abandoned,
they can be isolated from active workings of
the mine with explosion-proof bulkheads.
Pub. L. 91–173 (Dec. 1969) Section
303(2)(3)).
In the conference report filed in the
House, the statement of the managers on
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the part of the House stated, regarding
the requirement that an abandoned area
of a mine either be ventilated or sealed
that:
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[t]he determination of which method
[(ventilated or sealed)] is appropriate and the
safest at any mine is up to the Secretary or
[her] inspector to make, after taking into
consideration the conditions of the mine,
particularly its history of methane and other
explosive gases. The objective is that [s]he
require the means that will provide the
greatest degree of safety in each case. * * *
When sealing is required, such sealing shall
be made in an approved manner so as to
isolate with explosion-proof bulkheads such
areas from the active working of the mine.
Under the conference substitute, paragraph
(3) of section 303(z) provides that, in the case
of mines opened on or after the operative
date of this title, or in the case of areas
developed on or after such date in mines
opened prior to such date, the mining system
shall be designed, in accordance with a plan
and revisions thereof approved by the
Secretary and adopted by the operator, so
that, as each set of cross entries, room entries,
or panel entries of the mine are abandoned,
they can be isolated from active workings of
the mine with explosion-proof bulkheads
approved by the Secretary or his inspector.
The managers expect the Secretary to take
the lead in improving technology in this area
of controlling methane accumulations in gob
areas and to improve upon this important
section 303(z).
Conf. Rep. No. 91–761, 91Fst Cong. 1st
Sess., 82 (Dec. 16, 1969) (statement of
the managers on part of the House)
(emphasis added).
The Mine Act interim mandatory
standards required seals to be ‘‘made in
an approved manner so as to isolate
with explosion-proof bulkheads such
areas from the active workings of the
mine.’’ 30 U.S.C. 863(z)(2).
On May 15, 1992, as part of a
comprehensive revision of its
regulations for ventilation of
underground coal mines, MSHA
published standards for construction of
seals in § 75.335 of the ventilation
standards. The standard requires seals
to be constructed of solid concrete
blocks at least six inches by eight inches
by sixteen inches, but allows seals to be
constructed using alternative methods
and materials, provided, among other
things, that the seal is capable of
withstanding a horizontal static
pressure of 20 psi. MSHA based this
threshold on a U.S. Bureau of Mines
1971 report entitled ‘‘Explosion-Proof
Bulkheads—Present Practices.’’
A number of manufacturers
developed materials, such as
cementitious foams and glass-fiber
material, which were tested and
subsequently deemed suitable for use in
alternative seals and marketed under
various trade names. MSHA required
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the manufacturers to have full-scale
seals be subjected to explosion testing at
NIOSH’s Lake Lynn Experimental Mine
(Lake Lynn). MSHA then intended for
mine operators to construct seals as
constructed and tested at Lake Lynn.
On January 2, 2006, an explosion at
the Sago Mine in Upshur County, West
Virginia caused the death of twelve
miners. Later that year, on May 20,
2006, an explosion at the Darby Mine
No. 1 in Harlan County, Kentucky,
caused the death of five miners.
Common to both of these accidents was
the failure of the seals in the mine. The
failed seals in both mines were
constructed with the same approved
alternative material for a 20 psi seal.
None of the failed seals were
constructed in the same manner as they
were constructed at Lake Lynn.
Therefore, MSHA issued a moratorium
on alternative methods and materials for
construction of new seals (Program
Information Bulletin (PIB) No. P06–11,
June 1, 2006, reissued on June 12, 2006
as PIB No. P06–12.).
Following these underground coal
mine disasters in 2006, Congress passed
and the President signed the MINER
Act. Section 10 of the MINER Act
requires that the Secretary issue
mandatory health and safety standards
for seals of abandoned areas no later
than December 15, 2007. It also requires
the Secretary to revise the current
standard to increase the 20 psi standard
for alternative seals.
Seal failures at the Sago Mine and
Darby No. 1 Mine in 2006 raised
awareness of the problems with seal
construction and the design criterion of
a 20-psi static horizontal pressure.
MSHA continued its investigation of
these and other failures of alternative
seals, and conducted in-mine
evaluations of existing alternative seals.
It also reviewed the history of seals in
the United States and other countries.
Presently, most coal producing
countries have coal mine seal
requirements that are in excess of a 20psi overpressure. As a result of MSHA’s
continued investigations and in-mine
evaluations, MSHA increased the
strength of alternative seals to 50 psi
and addressed a number of other issues
related to the construction and the
effectiveness of current alternative and
solid concrete block seals in Program
Information Bulletin No. P06–16, ‘‘Use
of Alternative Seal Methods and
Materials Pursuant to 30 CFR
75.335(a)(2)),’’ issued on July 19, 2006
(July 2006 PIB).
On February 8, 2007, NIOSH issued a
draft report, ‘‘Explosion Pressure Design
Criteria for New Seals in U.S. Coal
Mines’’ (2007 NIOSH Draft Report). The
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28799
draft report states that ‘‘mine seals and
their related systems such as the
monitoring, inertization and ventilation
systems require the highest level of
engineering and quality assurance.
Successful implementation of the seal
design criteria and recommendations in
this report should reduce the risk of seal
failure due to explosions in abandoned
areas of underground coal mines.’’ (2007
NIOSH Draft Report at 40). In the
executive summary of the draft report,
NIOSH makes recommendations for
formulating seal design criteria.
B. General Discussion
Existing § 75.334(a) requires that
inactive areas of underground coal
mines be ventilated or sealed. Most
inactive areas are sealed because of
ground control, ventilation issues, and
the long-term costs of maintaining
ventilation and roof support in inactive
areas. Seals are also installed to
withstand overpressures resulting from
explosions in inactive areas and to
prevent the potentially explosive
methane/air mixtures from migrating to
the working areas.
A methane/air mixture becomes
explosive when 5 percent to 15 percent
methane is present with at least a 12
percent oxygen concentration. If an
ignition source is available, then an
explosion can occur and create high
overpressures. The homogeneity of the
methane/air mixture contributes to its
explosiveness. The homogeneity of the
methane/air mixture can vary
depending on the elevation and the
methane liberation of the sealed area
and outside factors such as the current
temperature and barometric pressure.
The speed of an explosion and the
physical characteristics of a sealed area
can increase the force of the explosion
such that detonations and significant
pressure piling are possible.
In order to address mine conditions
that influence the magnitude of
overpressures in explosions, seals need
to be designed and constructed properly
and then inspected on a periodic basis
and properly maintained to ensure their
reliability. The 2007 NIOSH Draft
Report states as follows:
NIOSH engineers examined seal design
criteria and practices used in the U.S.,
Europe and Australia and then classified
seals into their various applications. Next,
NIOSH engineers considered various kinds of
explosive atmospheres that can accumulate
within sealed areas and used simple gas
explosion models to estimate worst case
explosion pressures that could impact seals.
Three design pressure pulses (pressure-time
curves) were developed for the dynamic
structural analysis of new seals under the
conditions in which those seals may be used:
unmonitored seals where there is a
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possibility of methane-air detonation behind
the seal; Unmonitored seals with little
likelihood of detonation; and monitored seals
where the amount of potentially explosive
methane-air is strictly limited and controlled.
These design pressure pulses apply to new
seal design and construction.
For the first condition, an unmonitored
seal with the possibility of detonation, the
recommended design pulse rises to 4.4 MPa
(640 psi) and then falls to the 800 kPa (120
psi) constant volume explosion overpressure.
For unmonitored seals without the
possibility of detonation, a less severe design
pulse that simply rises to the 800 kPa (120
psi) constant volume explosion overpressure,
but without the initial spike, may be
employed. For monitored seals, engineers
can use a 345 kPa (50 psi) design pulse if
monitoring can assure (1) that the maximum
length of explosive mix behind a seal does
not exceed 5 m (15 ft) and (2) that the volume
of explosive mix does not exceed 40% of the
total sealed volume. Use of this 345 kPa (50
psi) design pulse requires monitoring and
active management of the sealed area
atmosphere.
Based on MSHA’s accident
investigation reports of Sago and Darby
mine explosions, NIOSH reports on
explosion testing and modeling,
MSHA’s in-mine seal evaluations, and
review of technical literature, MSHA
identified a number of issues pertinent
to the construction and efficacy of
current alternative and solid concrete
block seals.
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C. Section-by-Section Analysis
1. Sec. 75.335 Seals Requirements
The ETS increases seal strength
requirements for construction of new
seals and, where necessary, establishes
new requirements for monitoring and
inerting atmospheres of sealed areas.
New § 75.335(a) provides that seals
constructed in underground coal mines
after May 22, 2007 must be designed,
constructed and maintained in
accordance with MSHA approval of a
mine operator’s design application and
installation procedures incorporated in
the ventilation plan.
The ETS establishes a three-tiered
approach for overpressure loading
criteria applicable to new seals: (1) 50
psi overpressure; (2) 120 psi
overpressure; and (3) an overpressure
greater than 120 psi. For purposes of
this ETS, MSHA intends that
overpressure be any pressure exerted by
the forces of an explosion that is above
normal atmospheric pressure. In
developing these overpressure loading
criteria, MSHA relied upon the 2007
NIOSH Draft Report, the Agency’s safety
and health experience with respect to
seals and underground mining
conditions and investigations, and
accepted scientific and engineering
principles.
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Under the ETS, if a mine operator
monitors and maintains the atmosphere
in these areas inert, new § 75.335(a)(1)
requires a seal design to withstand at
least 50 psi overpressure. If a mine
operator does not monitor and maintain
atmospheres in these areas inert, new
§ 75.335(a)(2) requires a seal design to
withstand at least 120 psi overpressure.
A seal design that will withstand an
overpressure greater than 120 psi is
required under new § 75.335(a)(3) when
the mine operator does not monitor and
maintain the atmosphere within sealed
areas inert and when: (1) The
atmosphere in the area is likely to
contain homogeneous mixtures of
methane between 4.5 percent and 17.0
percent, and oxygen exceeding 17.0
percent throughout the entire sealed
area; (2) or pressure piling is likely due
to opening restrictions near the
proposed seal area; or (3) other
conditions are encountered, such as the
likelihood of a detonation in the
proposed seal area. Where the
conditions in § 75.335(a)(3) are likely to
occur, the mine operator must revise the
ventilation plan required by existing
§ 75.370 to address the appropriate seal
strength.
The ETS does not require mine
operators to upgrade seals constructed
prior to May 22, 2007. However, new
§ 75.335(b) enhances the protection
afforded miners under the previous
standard by requiring, among other
things, that atmospheres in the sealed
areas be monitored and inerted. If a
mine operator does not monitor and
inert the atmosphere in an existing
sealed area, the strength of the seals
must be increased to 120 psi or greater.
a. Sec. 75.335(a)
New paragraph (a)(1) requires that
seals be constructed to withstand 50 psi
overpressure. However, mine operators
who construct these seals must monitor
the atmosphere behind the seals and
maintain them inert. Mine operators are
currently required to construct seals that
will withstand 50 psi overpressure
under the July 2006 PIB. In addition, the
July 2006 PIB required mine operators
to assess atmospheres behind alternative
seals and take remedial action where
necessary. The 2007 NIOSH Draft
Report also recommends a 50 psi
overpressure for monitored and
managed atmospheres behind sealed
areas. Monitoring sealed areas allows
the mine operator to know the
composition of potentially hazardous
gases in sealed areas. Use of a 50 psi
overpressure seal requires the mine
operator to maintain an inert
atmosphere in the sealed area since
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explosions cannot occur within inert
atmospheres.
MSHA believes that in mines that
liberate significant volumes of methane,
the atmosphere in sealed areas will
become inert naturally. In mines that
produce very small volumes of methane,
the atmosphere in sealed areas may
never approach explosive methane/air
mixtures of 5 percent. However, some
mines may need to actively inert the
atmosphere in the sealed area. To inert,
an inert gas such as nitrogen or carbon
dioxide may be injected into the sealed
area through boreholes or pipes
extending through the seals. The gas
may be obtained from a bulk plant and
trucked to the mine site and pumped
into the sealed area through a borehole
or pipe into the seal. It also may be
produced at the mine using a nitrogen
generator, Tomlinson Boiler, or other
inertization device. This process is
commonly used in underground coal
mines in the United States during
firefighting activities and in other
countries where spontaneous
combustion is common. MSHA is
interested in receiving comments
regarding: (1) The economic and
technological feasibility of monitoring
and inerting sealed atmospheres; and (2)
methods of inerting sealed atmospheres.
New paragraph (a)(2) requires 120 psi
overpressure if the sealed atmosphere is
not monitored and maintained inert
except as provided in new paragraph
(a)(3). This provision allows mine
operators to install seals that withstand
120 psi overpressure if they do not
choose to monitor and inert the sealed
atmosphere. In MSHA’s experience, the
overwhelming majority of underground
coal mine explosions are typically
deflagrations. A deflagration occurs
when the flame of an explosion
propagates through unburned fuel at a
velocity below the speed of sound. The
faster the flame travels, the higher the
pressures become. Maximum pressures
in a deflagration involving methane or
coal dust are limited to approximately
120 psi without the occurrence of
detonation or significant pressure
piling. MSHA accident reports during
the past 30 years do not reference an
underground coal mine explosion in the
United States that generated an
overpressure of greater than 120 psi
except in the rare instance when
detonation occurred.
New paragraph (a)(3) also addresses
overpressures resulting from pressure
piling and detonations. Methane is
explosive between 5 percent and 15
percent and requires at least 12 percent
oxygen to ignite. (NIOSH 2006, IC 9486)
When ignited, an explosion can occur.
To account for correction factors of
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methane detection equipment and
potential contamination of the samples,
the ETS requires that methane
concentrations between 4.5 percent and
17.0 percent shall be used to determine
an explosive atmosphere. If ignited,
large volumes of homogeneous
explosive methane/air mixtures in a
sealed area can generate high explosion
overpressures. The homogeneity of
methane/air mixtures in a sealed area is
affected by a number of factors such as
elevation, temperature, methane
liberation, and barometric pressure.
Based on Agency experience, MSHA
anticipates that there will be few mines
that have homogeneous explosive
methane/air mixtures throughout the
entire area to be sealed. Commenters are
encouraged to submit information, with
supporting documentation, regarding
the number of mines that may have
homogeneous explosive methane/air
mixtures throughout the entire area to
be sealed.
MSHA believes that detonations and
significant pressure piling may occur
under certain situations. Detonations in
underground coal mines are rare. A
detonation occurs when the flame of an
explosion propagates through the
unburned fuel at a velocity exceeding
the speed of sound (1129 feet per
second). Pressures resulting from a
detonation involving methane or coal
dust can exceed 250 psi. Pressure piling
occurs when the atmosphere ahead of
the flame front is compressed prior to
the arrival of the flame. When the flame
burns through this compressed mixture,
an increase in the explosion pressure
occurs. Thus, if this mixture is
compressed to 45 psi prior to the flame
arriving, the resulting explosion
pressure could exceed 300 psi. Pressure
piling can occur when the physical
configuration through which the
explosion will propagate inhibits the
flow of gases for pressure equalization,
such as decreasing the number of
entries, decreasing the size of the
entries, or obstructing the entry.
The ETS does not specify a seal
strength under paragraph (a)(3). Under
this provision, the mine operator would
submit a strength requirement based on
mine-specific conditions that are likely
to result in pressure piling or detonation
in the sealed area. The mine operator
must first recommend the seal strength
in the ventilation plan. MSHA expects
that mine operators will submit a
thorough engineering analysis
conducted by a person knowledgeable
in explosions and explosion
overpressures, based on the conditions
in the mine. After the seal strength is
approved by the District Manager, the
process in § 73.336 will apply. MSHA
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expects that in these few instances, the
District Manager and the Office of
Technical Support will coordinate
MSHA activities related to the approval
process. MSHA believes that most mine
operators who encounter homogenous
explosive methane/air mixtures and
pressure piling in the entire sealed area
will monitor and inert the atmosphere
in sealed areas. Although the
recommended maximum seal strength
in the 2007 NIOSH Draft Report is 640
psi, MSHA has no empirical or other
data, at this time, demonstrating that
mine conditions exist that will
necessitate seals stronger than 120 psi.
MSHA requests comments from the
mining community on the
appropriateness of the strategy in this
ETS for addressing seal strength greater
than 120 psi.
In the ETS, MSHA considered a
performance-based approach to the
strength requirement for seals. However,
MSHA included specific numbers for
the strength of seals in the ETS as the
agency believes this represents a more
appropriate approach. MSHA
specifically solicits comments on the
Agency’s approach to the strength
requirement for seals.
MSHA is also interested in receiving
comments on the appropriateness of the
three-tiered approach to seal strength in
the ETS. If commenters believe a
different regulatory approach should be
developed for the final rule the Agency
would like commenters to provide: (1)
The details for such a strategy, (2)
rationale for such a strategy; and (3)
feasibility of using such strategy. The
Agency particularly seeks the views of
the mining community regarding
whether there are other effective
alternatives to the requirements in the
ETS with respect to providing the most
appropriate and protective action for
miners exposed to hazards of existing
sealed areas. Commenters should
provide supporting data, and specific
alternatives, including information on
technological and cost implications.
Most existing seals were constructed
to withstand a static horizontal pressure
of 20 psi. MSHA also considered
requiring mine operators to remove
existing seals and replace them with
seals that withstand at least 50 psi.
Currently, the Agency believes that
replacing existing seals is impractical,
and in some instances, may create safety
hazards. In addition, these existing seals
must be monitored and the atmospheres
behind them must be maintained inert.
The atmosphere inby and outby the
seals near the roof, ribs, or floor adjacent
to the seal may contain low oxygen and/
or explosive methane/air mixtures that
are highly hazardous to miners’ safety.
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In addition, the conditions inby the
seals, such as bad roofs, roof falls, and
water accumulations, may prevent the
mine operator from making changes to
provide adequate ventilation inby the
seals. MSHA seeks comments on the
feasibility of including in the final rule
a requirement that existing seals be
removed and replaced with a higher
strength seal.
Another regulatory option that MSHA
considered is whether to require mine
operators to build new seals outby
existing seals. In some cases, this may
not be feasible because the seals may
have been constructed too close to the
outby corner of the pillar so that there
is insufficient space to build new seals
in the same pillar; and there may not be
an additional open entry outby the
existing seals allowing for construction
of new seals.
MSHA also considered whether to
require mine operators to reinforce
existing seals. The Agency is concerned
with the feasibility of this option and
whether such a requirement could
expose miners to greater hazards as
discussed earlier in this preamble.
MSHA, however, will continue to
explore technological advances
addressing feasible and safe methods to
reinforce existing seals in underground
coal mines. Commenters are encouraged
to submit information and supporting
data regarding new technologies to
reinforce seal strength.
Existing § 75.335(a) included
minimum specifications for seals
constructed of solid concrete blocks
after November 15, 1992. Also, existing
§ 75.335 (a)(2) allowed mine operators
to use alternative construction methods
or materials to construct a seal provided
the seal could withstand a static
horizontal pressure of 20 psi
(subsequently increased to 50 psi in the
July 2006 PIB). In addition, the method
of installation and material used had to
be approved by the District Manager
under MSHA’s ventilation plan
procedures in § 75.370 based on a 1971
report entitled ‘‘Explosion-Proof
Bulkheads—Present Practices,’’ issued
by the former U.S. Bureau of Mines.
According to that report, when a sealed
atmosphere has adequate incombustible
material and minimum coal dust
accumulations, it is doubtful that
pressures exceeding 20 psi could occur
very far from the origin of the explosion.
The primary disadvantage of this level
of explosion protection is that current
evidence establishes that explosions of
coal dust or methane can generate
explosion pressures of 120 psi, without
detonation or pressure piling.
Previous § 75.335(a)(2) also included
measures to prevent exposed timber
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seals from quickly failing in a fire or
other mine emergency. New
construction of timber seals must meet
the requirements set forth in this ETS.
b. Sec. 75.335(b) Sampling and
Monitoring Requirements
ETS § 75.335(b) establishes new
sampling and monitoring requirements
for sealed areas. This provision requires
that on the effective date of this ETS, a
certified person, as defined under
existing § 75.100, must immediately
monitor atmospheres in all existing
sealed areas when seals are outgassing,
such as when the barometric pressure in
the sealed area exceeds the pressure on
the outby side of the sealed area. MSHA
intends for mine operators to establish
a baseline analysis over a 14-day
sampling period, as specified under
§ 75.335(b)(5)(iii), followed by weekly
sampling under paragraph (b)(1) of this
section. While sampling is being
conducted, mine operators must train
certified persons in sampling
procedures and develop a sampling
protocol to be included in the
ventilation plan and submitted to the
District Manager for approval.
This provision also requires that for
seals constructed prior to May 22, 2007
and seals designed for 50 psi
overpressure according to ETS
§ 75.335(a)(1), mine operators shall
develop and follow a protocol to
monitor methane and oxygen
concentrations and to maintain an inert
atmosphere in sealed areas. The
protocol shall be approved in the
ventilation plan. The sampling protocol
must ensure that an inert atmosphere
behind the seal area is maintained. An
explosion will not occur in an inert
atmosphere. The July 2006 PIB and this
ETS require mine operators to conduct
an atmospheric assessment behind
existing alternative seals to determine
the potential for an explosion and assess
seal integrity. This ETS requirement
enhances protection of miners working
in the active portions of the mine
adjacent to sealed areas where existing
seals were installed prior to this ETS. In
addition, this provision protects the
miner where 50 psi seals will be
installed under this rule. MSHA
recognizes that conditions in mines may
vary and mine operators can more
appropriately address their specific
conditions in the ventilation plan.
During 2006, MSHA inspected existing
seals. The inspections revealed that
some mine operators were not adhering
to their approved ventilation plan for
seal installation and construction. The
ETS emphasizes the importance of
sampling sealed atmospheres to ensure
that they remain inert.
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ETS § 75.335(b)(1) requires that a
trained certified person sample
atmospheres of sealed areas weekly
when the barometric pressure is
decreasing or the seal is outgassing.
Because the information obtained
during sampling of a sealed area is
critical to the safety of miners, the ETS
requires sampling to be conducted by a
certified person. At least one sample
shall be taken at each set of seals. If a
seal is ingassing, such as when the
barometric pressure outside the sealed
area exceeds the pressure on the inby
side of the sealed area during the
weekly examinations, the ETS requires
that a sample shall be collected during
the next weekly examination to
determine if the seal will outgas. If the
seal is ingassing during the second
consecutive weekly examination, the
operator shall examine that seal daily
until the seal is outgassing, unless the
seal does not outgas. In this
circumstance, an alternative protocol
must be developed to effectively
evaluate the atmosphere in the sealed
area and submitted to the District
Manager for approval. Although the ETS
does not specify the length of time that
the seal must be examined to determine
if it will outgas, MSHA intends to
require mine operators to develop the
alternative protocol within a reasonable
timeframe. The District Manager may
approve different sampling frequencies
and locations in the ventilation plan or
approve the use of atmospheric
monitoring systems in lieu of weekly
sampling. The mine operator shall
revise the protocol in the ventilation
plan if repeated sampling indicates that
a seal is not likely to outgas.
MSHA expects that the certified
person will conduct sampling required
under the ETS as part of the
examinations of seals required in
existing § 75.360 and § 75.364 and base
the time of these examinations on the
barometric conditions to the extent
possible. All seals and the strata around
them will leak air, resulting in an air
exchange near the seal during
barometric changes. MSHA does not
expect the air leakage to significantly
impact the atmosphere in a large portion
of the sealed area, but it may affect the
atmosphere at a sampling location when
the seal is ingassing. Therefore, it is
important that samples be
representative of the atmospheric
conditions in the larger portion of the
sealed area, rather than just the area
immediately inby the seal.
The certified person must take at least
one sample at each set of seals during
the weekly examination. Each newly
constructed seal must be equipped with
two sampling pipes. In accordance with
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the ETS, MSHA expects that most mines
will need to take only one sample from
a seal in each set of seals. However, the
number of seals that need to be sampled
will be determined from the results of
the 14-day sampling period specified in
paragraph (b)(5)(iii) of this section.
If the seal is ingassing during the
examination, the certified person must
attempt to take a sample during the next
weekly examination. After a second
attempt is made and the seal is still
ingassing, attempts must be made daily
until the seal outgasses. If repeated
sampling indicates that a seal is not
likely to outgas, then the mine operator
must submit an alternative protocol to
the District Manager. The alternative
protocol must address a means to
effectively evaluate the atmosphere in
the sealed area. The alternate protocol
may address various means such as: (1)
The use of a borehole or previously
installed sampling line to obtain
samples, (2) pressure balancing of the
ventilation system to make the seals
outgas, or (3) the use of inert gas
injection.
The District Manager may approve
different sampling frequencies and
locations in the ventilation plan. This is
intended to address those instances
when the atmosphere in the sealed area
is unstable, close to the explosive range,
or subject to other hazardous
conditions, such as a history of
spontaneous combustion, which make it
necessary to sample at a greater
frequency. However, a less frequent
sampling strategy may be approved in
the ventilation plan if the atmosphere in
the sealed area is stable and not at all
close to explosive range. For example,
the oxygen must be significantly below
10 percent, and methane far less than 3
percent or far greater than 20 percent.
Sampling requirements also addresses
instances when an adequate evaluation
of the atmosphere in the sealed area
cannot be obtained with the sampling
pipes located 15 feet inby the seal and
into the center of the first connecting
crosscut inby the seal. In some sealed
areas, the District Manager may find it
necessary to require in the ventilation
plan that samples be obtained at
additional locations to determine that
the atmosphere is inert. Additional
samples may need to be taken at mines
with sealed areas that are very large,
have multiple sets of seals, connect with
another mine, have flooded areas, have
capped shafts, or in other circumstances
which may cause samples of the
atmosphere taken near the seals not to
be representative of the entire sealed
area.
The ETS also allows the use of an
Atmospheric Monitoring System (AMS)
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in lieu of a person physically taking
samples on a weekly basis. The use of
AMS is discussed more fully under
paragraph (b)(5)(vi) of this section.
MSHA believes that the sampling
strategy in this ETS will yield results
that reflect a reasonable representation
of the atmosphere in a sealed area.
MSHA is requesting comments
addressing the sampling approach in
this ETS. The agency is particularly
interested in comments concerning
sampling, and the sampling frequency,
including sampling only when a seal is
outgassing. The Agency requests
comments on whether another sampling
approach is more appropriate for a final
rule, such as when the seal is ingassing.
MSHA also requests comments,
information, and experiences of the
mining community concerning
sampling sealed areas.
Paragraph (b)(2) requires that certified
persons shall be trained in sampling
procedures included in the protocol at
paragraph (b)(5) of this section prior to
conducting sampling. This requirement
would ensure that certified persons
conducting the sampling have the
training necessary to use the sampling
devices and knowledge of the sampling
protocol requirements in the mine’s
ventilation plan.
This training shall be conducted by
persons with knowledge of the
requirements in paragraph (b)(5) of this
section. Training may be conducted by
a variety of people, including a
manufacturer’s representative,
ventilation engineer or a certified
person at the mine. MSHA expects the
operator to utilize appropriate people to
conduct the training.
At a minimum, this training should
include:
1. Relevant information in the mine’s
ventilation plan;
2. Sampling procedures including
equipment and methods to be used;
3. Location of sampling points and
sampling pipes;
4. The baseline analysis of oxygen and
methane concentrations in a sealed area
over a 14-sampling day period;
5. Frequency of sampling for each set
of seals;
6. Recording procedures required in
paragraph (b)(6) of this section;
7. Sampling frequency in the mine’s
ventilation plan, if an AMS is used; and
8. General information concerning
mine gases present in sealed areas.
Training should include specific
actions to take in implementing the
operator’s ‘‘action plan’’ when methane
concentrations are at one of three
different ranges and oxygen
concentrations are 10.0 percent or
greater.
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MSHA recognizes that the amount of
time required to train a certified person
will vary. For this reason, MSHA is not
specifying a minimum amount of time
for training, but instead a requirement
that is performance-oriented. MSHA
anticipates that mine operators will
adjust the time required for this training
based on the complexity of sampling
procedures, sampling protocol, and
existing knowledge and skill level of the
certified person. MSHA also expects
operators will include ‘‘hands-on’’
training during this session to assure
that the certified person demonstrates
the necessary skills and abilities to
perform the tasks. Hands-on training
would mean that a certified person
demonstrates to the trainer the
necessary skills and abilities to perform
the testing for oxygen and methane.
Hands-on training includes practical
application of the type of sampling
equipment and the methods to be used
at the mine. Examples of this type of
training include calibration of sampling
equipment, setup of equipment, and
recognition of the proper functioning of
equipment.
All certified persons shall receive
refresher training annually to ensure
that they maintain the competence
necessary to effectively perform the
requirements in paragraph (b)(5) of this
section. Annual retraining shall be
required within 12 months of the person
receiving initial or annual training. For
example, a certified person receiving
initial training in May 2007 is expected
to complete annual retraining no later
than the end of May 2008. The month
that the refresher training is completed
establishes the anniversary month for
the next annual retraining. This is
consistent with other MSHA training
requirements.
This ETS also requires mine operators
to certify the date and content of the
training provided to the certified
person. Operators are required to retain
these certifications for one year from the
time training was conducted. This
provision is similar to other certification
requirements in part 75 in which the
operator certifies by signature and date
that training was provided.
ETS § 75.335(b)(3) states that the
atmosphere in the sealed area is
considered inert when any of the
following conditions occur:
(1) The oxygen concentration is less
than 10.0 percent;
(2) The methane concentration is less
than 3.0 percent; or
(3) The methane concentration is
greater than 20.0 percent.
This ETS provision is consistent with
MSHA guidance published in the July
2006 PIB. The explosive range of
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methane is 5 to 15 percent when the
oxygen level is 12 percent or more (IC
9486, 2007 NIOSH Draft Report). To
allow for the inaccuracy of methane and
oxygen detection equipment and
potential contamination of the samples,
oxygen less than 10.0 percent, methane
concentration less than 3.0 percent and
methane concentration greater than 20.0
percent were used to determine an inert
atmosphere.
ETS § 75.335(b)(4) requires that when
oxygen concentrations are 10.0 percent
or greater and methane concentrations
are from 3.0 percent to 20.0 percent in
a sealed area, the mine operator shall
take two additional gas samples at one
hour intervals. If the two additional gas
samples are from 3.0 percent to 20.0
percent methane and oxygen is 10.0
percent or greater, then the mine
operator shall initiate actions required
in ETS § 75.335(b)(4)(i) or (ii). The
ranges for methane and oxygen in this
paragraph include a margin of safety,
account for errors in instrumentation or
sampling methods (NIOSH IC 9486),
and allow the mine operator to obtain
confirming samples before
implementing the actions outlined in
(b)(4)(i) and (b)(4)(ii). However, because
the atmosphere in the sealed area is
critical to the safety of miners, the ETS
requires that samples be taken at onehour intervals under § 75.335(b)(4).
Paragraphs (b)(4)(i) and (b)(4)(ii) of
the ETS require the mine operator to
implement the action plan specified in
the protocol or to withdraw all persons
from the affected area when the
specified concentrations are
encountered. Historically, when
methane levels reached 4.5 percent in
active areas of mines, miners were
withdrawn from the areas that were
dangerous due to high concentrations of
methane. However, withdrawal of
miners is not required if, under
paragraph (b)(4)(i), the operator chooses
to implement the action plan to address
the actions to be taken by mine
operators when the specified
concentrations in § 75.335(b)(4) are
reached; these concentrations provide a
margin of safety. However, the action
plan must be approved in the mine’s
ventilation plan and must provide
protection to miners equivalent to
withdrawal under paragraph (b)(4)(ii).
MSHA requests comments on this
approach and whether it provides
adequate protection for miners.
Commenters are encouraged to submit
specific language, with supporting data
for MSHA to consider for development
of a final rule.
ETS § 75.335(b)(5) establishes the
elements that must be addressed in a
mine operator’s sampling protocol and
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actions to be taken when sampling
results indicate that the atmosphere
behind the sealed area is not inert.
Paragraph (b)(5)(i) requires that the
mine operator specify sampling
procedures, including the type of
equipment and methods to be used by
the mine operator for the sampling
program. MSHA believes most mine
operators will use hand-held methane
and oxygen detection equipment that
they currently have at the mine site.
Other operators may need to purchase
detectors capable of measuring high
levels of methane. Although the mine
operator may collect samples in
containers to be analyzed by a gas
chromatograph, the operator must
specify in the protocol when the sample
will be analyzed and the procedures
that will be followed when the sample
results indicate action levels are
reached. The methods to be used should
include the physical connections to the
sample pipes as well as the length of
time the detector or pump should be
operated to collect the sample. The
length of time will be dependent on the
length of the sampling pipes.
ETS § 75.335(b)(5)(ii) requires that the
mine operator specify in the sampling
protocol the location of sampling points
used for the sealed area in a set of seals.
The sampling points should be
identified on a mine map, or the
operator should have a narrative
description of the location of the
sampling points that can be readily
identified on a mine map.
ETS § 75.335(b)(5)(iii) requires that
the mine operator specify procedures in
the protocol to establish a baseline
analysis of oxygen and methane
concentrations at each sampling point
over a 14-day sampling period. For
existing seals, the mine operator must
begin this sampling upon the effective
date of this rule. For newly constructed
seals, the mine operator must begin this
sampling upon completion of the seal
construction.
The baseline shall be established after
the atmosphere in the sealed area is
inert or the trend reaches equilibrium.
These samples would be taken by
approved hand-held gas detectors or
equipment that collects samples in
containers to be analyzed by gas
chromatograph. These samples need to
be collected over a consecutive 14-day
sampling cycle to establish a baseline
for a future sampling cycle at each
sampling point. Samples need only be
taken when the seals are outgassing
during the baseline period to ensure
samples are representative of the larger
area inby the seals. If the seals are not
outgassing during any of the days of
sampling, the baseline sampling period
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needs to be extended until 14 samples
are taken. Once a baseline is
established, the seals need to be
sampled at least weekly. MSHA is
requesting comments on this sampling
approach. The agency is particularly
interested in comments concerning the
establishment of a baseline, including
sampling only when a seal is outgassing
and whether it is appropriate to sample
the atmosphere in sealed areas during
ingassing. MSHA also requests
comments, information, and
experiences with sampling sealed areas,
including data, analytical information,
establishment of equilibrium, and
trends.
ETS § 75.335(b)(5)(iv) establishes the
frequency of sampling at each seal or set
of seals. Once a baseline is established,
the seals must be sampled at least
weekly while the seals are outgassing.
Weekly examinations under existing
§ 75.364 cannot exceed a 7-day interval.
Mine operators may conduct sampling
required under this ETS in conjunction
with weekly examinations under
existing § 75.364. Depending on the
location and the results of sampling,
MSHA may require that seals or sets of
seals be sampled at different sampling
intervals. Additionally, there may be
circumstances where seals or sets of
seals within a single sealed area, have
a different sampling frequency.
ETS § 75.335(b)(5)(v) requires that the
mine operator specify size and
conditions of the sealed area. Some
mine-specific conditions inby the sealed
area may include the type of mining, the
presence of pillared areas, the average
mining height, the occurrence of bottom
mining, any entry restrictions near the
seals, the size of the sealed area and the
number of seals in each set of seals. This
information is important to determine
the appropriate seal strength.
ETS § 75.335(b)(5)(vi) requires that
the protocol address an atmospheric
monitoring system (AMS) to monitor
sealed areas, where applicable. MSHA
may approve use of an AMS to monitor
methane and oxygen levels and pressure
differentials across the seals in lieu of a
person physically taking or collecting
methane samples. The AMS consists of
sensors to monitor methane and oxygen
levels in the sealed area and the
pressure differential across the seal.
ETS § 75.335(b)(5)(vii) requires that
the protocol include an action plan
addressing hazards presented and
actions taken when gas samples indicate
oxygen concentrations of 10.0 percent or
greater for each of the following ranges
of methane concentrations: (1) 3.0
percent or greater but less than 4.5
percent; (2) 4.5 percent or greater but
less than 17.0 percent; and (3) 17.0
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percent to 20 percent. MSHA expects
the action plan to address the risk to
miners based on the location of seals,
the locations of escapeways, the size
and nature of the sealed area, potential
impact of seal failure on the mine
ventilation system, and the exposure to
miners to any potential seal failures.
MSHA may require additional sampling
when methane ranges are between 3.0
and up to 4.5 percent and from over
17.0 percent to 20 percent, as well as
possible changes to the ventilation
system, or the addition of inert gas to
the sealed area. A methane range
between 4.5 and 17.0 percent and an
oxygen level greater than 10 percent
requires the mine operator to follow the
action plan set forth in the protocol in
the ventilation plan or to evacuate
miners from the affected area of the
mine. If miners must be withdrawn, the
only persons who may remain in the
affected area are those persons referred
to in section 104(c) of the Mine Act.
ETS § 75.335(b)(6) requires that the
certified person promptly record each
sample result from sealed areas,
including the location of sampling
points, and oxygen and methane
concentrations. The results of oxygen
and methane samples must be recorded
as the percentage of oxygen and
methane measured by the certified
person. Also, the ETS requires, where
applicable, that the certified person
promptly record monitoring results from
AMS systems.
If sampling and monitoring results
indicate the presence of a hazardous
condition to miners, the certified person
must record the hazardous condition
found in accordance with existing
§ 75.363 (Hazardous conditions; posting,
correcting and recording). Also
§ 75.335(b)(6) requires that hazardous
conditions be corrected immediately or
the area must be posted. In addition,
records of hazardous conditions must be
reviewed and countersigned by the
mine foreman, or equivalent mine
official, by the end of the mine
foreman’s or equivalent mine officials
next regularly scheduled working shift.
ETS § 75.335(b)(7) requires that the
mine operator retain sampling records at
the mine for at least one year from the
date of sampling. A one year retention
period permits the mine operator to
track trends or changes. The one year
retention period is consistent with
existing §§ 75.360 and 75.364.
c. Sec. 75.335(c) Welding
ETS § 75.335(c) prohibits the use of
open flames or arc associated with
welding, cutting, and soldering
activities within 150 feet of a seal.
MSHA intends to apply this
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requirement to seals when their
construction has been completed. The
use of an oxygen acetylene cutting torch
to cut a metal strap at a seal was the
most likely ignition source in the Darby
Mine No. 1 explosion in 2006. Although
the metal strap should have been
removed before the seal was
constructed, the event underscores the
importance of the potential dangers
when working near seals, and
emphasizes the dangers of using open
flames near a seal. A methane enriched
atmosphere can leak through the seal or
surrounding strata into the active area of
the mine. The methane may accumulate
and form a methane layer outby the seal.
If ignited, a flame can propagate into the
sealed area. The 150-foot limit is
consistent with an existing requirement
in § 75.1002(a)(1) that non-permissible
equipment be excluded within 150 feet
of pillar workings or longwall faces. In
determining the 150-foot distance,
MSHA provides guidance in MSHA’s
Program Policy Manual (Volume V-Coal
Mines February 2003, Release V–33)
which states that the 150-foot distance
shall be measured by following the
shortest distance that air can travel
(tight string distance) through crosscuts,
entries or other openings. MHSA does
not believe that this requirement will
present significant practical or technical
problems for the underground coal
mining industry. MSHA is requesting
comments from the mining community
on the appropriateness of the ETS
requirement regarding open flames
associated with welding, cutting and
soldering activities within 150 feet of a
seal and the feasibility of this
requirement. MSHA suggests that
commenters provide specific rationale
in support of their position, and include
alternatives, if applicable.
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d. Sec. 75.335(d)
Sampling Pipes
ETS § 75.335(d) revises previous
§ 75.335(b) and requires each newly
constructed seal to have at least two
sampling pipes. One sampling pipe
must extend into the sealed area
approximately 15 feet as required by
previous § 75.335(b). This provision of
the ETS is based upon sampling
procedures recommended in the 1979
MSHA study, ‘‘Interpreting the State of
a Mine Fire.’’ The study shows that in
sampling situations involving fires
behind sealed areas, sampling pipes
should extend at approximately 15 feet
toward the fire. This distance also
applied to atmospheric sampling in
sealed areas for non-fire situations. The
area directly inby a seal is more likely
to be affected by ingassing during
normal barometric changes.
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Under this provision, the second
sampling pipe must extend into the first
connecting crosscut inby each seal and
to the center of the first connecting
crosscut in the middle of the
intersection. MSHA has included this
new provision in the ETS so that the
operator can obtain a representative
sample of the sealed area. The Agency
believes that sampling points within the
first connecting crosscut will provide a
more representative sample of the
sealed area because this atmosphere is
less likely to be affected by ingassing.
The District Manager may require more
than two sampling locations in the
ventilation plan under § 75.335(b)(1).
ETS § 75.335(d) requires that each
sampling pipe be equipped with a shutoff valve and an appropriate fitting for
taking atmospheric samples behind the
seals. A tapered fitting, for example,
may be connected at the tip of the
sampling pipe to easily accommodate a
flexible tube attached to a gas analyzer.
The ETS allows for other types of
sampling methods that may be used to
monitor sealed atmospheres. ETS
§ 75.335(b) allows a mine operator to
use an atmospheric (gas) monitoring
system when appropriate. Although
MSHA no longer requires that sampling
pipes be installed with the sampling
end of the pipe to be about 12 inches
from the roof and in the centerline of
the entry, the most appropriate
placement of the sampling end of the
pipe should be about 12 inches from the
roof. The ETS affords flexibility to mine
operators for the placement of the
sampling end to allow more accurate
sampling strategies to better protect
miners. Therefore, the ETS requires that
the location of sampling points be
specified in the protocol provided under
ETS § 75.335(b)(5). MSHA requests
comments regarding the appropriate
number and location of sampling pipes
for a final rule.
e. Sec. 75.335(e) Water Drainage
Systems
ETS § 75.335(e) requires that a
corrosion-resistant, water drainage
system be installed in the seal at the
lowest elevation within the set of seals.
Water accumulations can affect the
integrity of seals since they are not
designed to impound water. Previous
§ 75.335(c)(2) required each water
drainage pipe to have a water trap outby
the seal. MSHA required the water trap
to prevent the exchange of air through
the seal and propagation of an
explosion. New seal designs under the
ETS, however, must meet performance
requirements for a drainage system
which prevents the exchange of air and
the accumulation and impoundment of
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mine water inby the seals. The ETS also
allows for use of new and innovative
designs. MSHA has determined that the
ETS provision enhances the level of
protection afforded under the previous
standard. ETS § 75.336(a)(1)(i) requires
that drainage system designs be
approved by MSHA, and ETS
§ 75.336(b)(3)(iii)(I) requires estimation
of the volume of water flow in the
ventilation plan. Depending on the size
and mine floor elevations of the sealed
area, it may be necessary for more than
one seal in a set of seals to contain a
water drainage pipe. These provisions
provide flexibility and additional
oversight by MSHA to help ensure safe
and effective water drainage systems to
protect miners from seal failure due to
water impoundment. The ETS prohibits
seals from impounding water.
MSHA requests comments from the
mining community on the ETS
requirement for water drainage systems
for seals, including effective alternatives
for a final rule.
2. Sec. 75.336 Seal Design
Applications and Installation Approval
The ETS requires that seal design
applications and installation procedures
be approved by MSHA prior to
construction. The ETS approval
requirements for seals are derived from
previous § 75.335(a)(2), the July 2006
PIB, and Procedure Instruction Letter
(PIL) No. I–06–V–09, ‘‘Procedures for
Approval of Alternative Seals,’’ issued
on August 21, 2006 (August 2006 PIL)
and are consistent with existing
requirements for approving coal mine
impoundments in § 77.216–2. Paragraph
(a) requires that seal design applications
be submitted to MSHA’s Office of
Technical Support for approval. Seal
design applications must conform to the
provisions provided in paragraph (a)(1)
or (a)(2) which address seal design and
installation approval. Once a seal design
is approved by MSHA, a mine operator
may use the design in accordance with
new provisions in paragraph (b) of this
section and the requirements of existing
ventilation standards in §§ 75.370,
75.371, and 75.372, which address the
submission and approval of the
ventilation plan.
Previous §§ 75.335(a), (b), and (c) that
address design parameters of seals are
transferred to ETS §§ 75.336 (a) and (b)
and are revised. These previous
provisions required mine operators to
either use a seal constructed of solid
concrete blocks or seals constructed of
alternative methods and materials if
approved in the mine’s ventilation plan.
Under the new provisions, a
manufacturer or mine operator may
submit an application for approval
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which can include any seal design. Seal
designs specified in previous § 75.335
may be submitted to MSHA for
approval, provided the proposed design
meets the strength requirements of ETS
§ 75.335(a). The provisions of ETS
§ 75.336(a) are derived from the July
2006 PIB that established criteria to
guide the District Managers’ approval of
the use of alternative seals in ventilation
plans. These provisions are also derived
from the August 2006 PIL that
established uniform procedures for
application of MSHA regulations related
to review and approval of ventilation
plans, which include alternative seals
constructed in underground coal mines
after July 19, 2006. Installation of seals
is required to be approved by the
District Manager in the ventilation plan
in accordance with ETS § 75.336(b).
a. Sec. 75.336(a)(1) Engineering Design
Applications
ETS § 75.336(a)(1), which is derived
from the August 2006 PIL, sets forth
specific requirements that an
engineering design application must
include. The requirements in
paragraphs (a)(1)(i) through (iii) are new
and are based on sound engineering
principles. They require that a seal
design application shall: (1) Address
design calculations and analyses, (2)
include certification by a professional
engineer, and (3) include a Seal Design
Table. The documentation required
under this paragraph includes design
calculations, drawings, and
specifications. Design calculations are
required, since they provide the
technical basis for developing drawings
and specifications and serve as the
record of the engineering design.
Drawings and specifications provide
detailed information necessary to
construct seals, technical requirements
for a seal, and important information
and guidance to be followed during seal
construction.
These ETS requirements are
consistent with existing approval
requirements for various mining-related
products under subchapter B—Testing,
Evaluation, and Approval of Mining
Products for permissibility and for
approval of impoundment designs
under existing § 77.216. Existing
approval regulations require applicants
to submit substantial engineering
documentation as the basis for approval.
The engineering documentation
provides MSHA with evidence that the
design meets accepted engineering
practices and principles.
ETS § 75.336(a)(1)(i) requires each
engineering design application to
address essential design parameters.
This information is required for MSHA
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to make a thorough assessment of the
design application to ensure that the
seal design will reliably withstand a
specific overpressure, and to verify that
the seal design is certified according to
ETS § 75.336(a)(1)(ii). MSHA will
review the application for evidence that
each of these design parameters is
sufficiently addressed.
The design application should show
the placement of gas sampling pipes
required under § 75.335(b). Also, the
application must address a water
drainage system. The drainage system
must be corrosion-resistant and should
not be subject to detrimental
environmental conditions. The
dimensions, material type, and
components of the water drainage
system should be specified. The
application should show how the water
drainage system will prevent both the
exchange of air and the propagation of
an explosion through the water drainage
system. Also, the application should
show how the water drainage system
will be able to withstand the applicable
overpressure in ETS § 75.335(a).
The design application must address
air leakage and should specify the
method and materials used to minimize
air leakage along the perimeter of each
seal and through any construction joints
or cracks that could develop. Consistent
with previous § 75.335(a)(iv) that
required that a sealant material should
have a flame-spread index of 25 or less,
the mine operator must address the
flame-spread index. The flame spread
index is established through recognized
laboratory testing such as that
designated by ASTM E162–07, ‘‘Surface
Flammability of Materials Using a
Radiant Heat Energy Source’’ or
equivalent.
The design application must include
appropriate information to address fire
resistance, such as methods and
materials used to provide at least onehour fire resistance. The fire resistance
is established through recognized
laboratory testing. The seal material
should not fail or allow transfer of
sufficient heat while being subjected to
a fire test incorporating an ASTM
E–119–07 time/temperature heat input,
or equivalent, for one hour.
A pressure-time curve provides the
necessary loading criterion for a seal
design and must be provided in the seal
design application. The pressure-time
curve provides the reflected
overpressure and constant-volume
pressure plotted as a function of a
specific time period. Pressure-time
curves for the 50-psi and 120-psi seal
strength requirements of ETS § 75.335(a)
are provided in the 2007 NIOSH Draft
Report. Alternative pressure-time curves
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may be used for designs provided the
pressure-time curves are submitted to
MSHA’s Office of Technical Support for
approval.
The applicant must document the
entry dimensions for which the seal
design is applicable and the engineering
design and analysis. MSHA expects the
design documentation, the design
assumptions, references of design
standards and guidance, material
properties and relevant test data,
presumptive geotechnical properties
and information, geotechnical test data
used to substantiate presumed
geotechnical properties, data to address
the long-term durability of seal
materials, loading criteria, design
calculations, and the identification of
computer software used and the
computer input and output files with
the critical design values indicated. The
design should also address the factors
used to account for the variability in
material properties, geologic conditions,
and the quality of construction. For
example, the applicant must show that
an appropriate approach was used to
derive the geotechnical and material
design values. The design should also
show the methodology and the
procedures used to evaluate all potential
failure modes of the seal and strata.
MSHA considers design standards and
guidance documents as appropriate
references, such as Army TM 5–1300,
‘‘Structures to Resist the Effects of
Accidental Explosions,’’ American
Concrete Institute ACI 318–05,
‘‘Building Code Requirements for
Structural Concrete and Commentary,’’
and American Concrete Institute ACI
440.2R–02, ‘‘Design and Construction of
Externally Bonded FRP Systems for
Strengthening Concrete Structures.’’
Specifications must be provided in
the seal design application to define the
performance requirements for
construction materials and equipment
used. Test methods and reference to
industry standards for materials (e.g.,
American Society for Testing and
Materials) that will be used in seal
construction must also be included in
the application. For construction
materials whose properties and
performance are not well-researched or
well-documented, the applicant would
be required to provide data
substantiating long-term durability and
strength.
Applications must provide
construction specifications adequately
addressing the preparation of the site for
seal construction. For example,
construction specifications must
include rock and coal removal
requirements for the foundation.
Specifications for foundations must
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The seal design should establish the
maximum allowable convergence a seal
may undergo without affecting the
structural integrity of the seal. The
design should also address other
physical limitations for a seal, such as
the time required following construction
to achieve the specified material
strength. For example, the time required
for an explosive atmosphere to develop
in a sealed area must exceed the time
required for the seal construction
material to achieve its specified
strength. The specified strength of a
material must take into account
variability in strength of the material.
The required material strength ensures
that the installed material strength of
the seal exceeds the specified design
strength.
The professional engineer designated
in ETS § 75.336(a)(1)(ii) is responsible
for the preparation, signing, dating,
sealing, and issuing of engineering
documents for the design of a seal.
Engineering decisions and actions that
must be made by and must be the
responsibility of the professional
engineer are:
address both the horizontal and vertical
surfaces of the mine opening. Keys
formed in rock and coal to increase the
lateral restraint must be excavated with
equipment that minimizes fracturing
and breakout. The applicant must also
specify the necessary actions to be taken
to prevent water accumulation in the
seal construction area since water
accumulation could affect material
strength. Necessary storage conditions
for construction materials, such as
moisture, heat, or shelf life should be
specified. Construction specifications
should also address formwork when a
seal construction involves cast-in-place
and pneumatically-applied materials.
The application must list provisions
that specify quality control procedures
for construction and include
requirements for material sampling and
testing. Material testing should be
conducted by personnel certified by
professional organizations such as the
American Concrete Institute and by
Nationally-Recognized Testing
Laboratories to ensure proper quality
control testing.
28807
1. The selection or development of
design standards or methods, and
materials to be used in seal
construction;
2. Development and preparation of
the structural analyses and design
computations, drawings, and
specifications;
3. The selection or development of
techniques or methods of testing to be
used in evaluating materials used either
during seal construction or following
completion of seal construction; and
4. The development of construction
procedures.
ETS § 75.336(a)(1)(iii) requires that a
Seal Design Table that discusses
characteristics related to mine-specific
construction be included in the
application. These characteristics
include the maximum entry width and
height for which the specific design is
applicable, specified strength of the seal
material, thickness of the seal, and the
reinforcement and foundation
anchorage requirements for the seal. The
mine operator may provide additional
information in the seal design
application.
EXAMPLE CONCRETE SEAL DESIGN TABLE
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b. Sec. 75.336(a)(2) Full-Scale
Explosion Test Application
ETS § 75.336(a)(2) provides
requirements for seal applications that
are based on full-scale explosion testing.
ETS § 75.336(a)(2)(i) requires that
explosion tests be certified by a
professional engineer knowledgeable in
structural engineering that full-scale
tests were conducted in accordance
with current, prudent engineering
practices and the results are applicable
to an underground coal mine. Current,
prudent engineering practices should
include the preparation, signing, dating,
certifying and issuing of engineering
documents for the design of a seal. The
decisions and actions that are the
responsibility of the professional
engineer are the same as stated above.
ETS § 75.336(a)(2)(ii) requires that the
application include technical
information related to the methods and
materials used during a successful fullscale explosion test. The testing should
include, at a minimum, the following
blast loadings: (1) The reflected
overpressure due to the blast wave of a
methane explosion, and (2) the
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Specified unconfined
compressive strength
(psi)
Thickness
(ft-in)
Entry dimensions (ft)
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Reinforcement
constant-volume pressure due to the
exothermic reaction of the combustion
of methane. The overpressures stated in
ETS § 75.335(a)(1) serve as the
minimum peak reflected overpressures
that a seal should be capable of
withstanding. Ideally, the seal should be
tested to its predicted ultimate strength
to determine the actual strength of the
seal. For example, seals should be tested
with the face perpendicular to the
direction of a blast wave and subjected
to a reflected overpressure, rather than
a side-on overpressure. The testing
program must address projectile impact
on the seals.
ETS § 75.336(a)(2)(ii) requires the
applicant to provide technical
information related to the methods and
material used to construct and test the
seals. The properties and laboratory test
data of the materials are required. The
laboratory test data should be provided
by personnel certified by professional
organizations such as the American
Concrete Institute and by a NationallyRecognized Testing Laboratory to ensure
proper quality control testing. MSHA
intends to substantiate the design values
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Foundation
anchorage
used in the analysis and the full-scale
testing of the seals.
ETS § 75.336(a)(2)(iii) requires that
the application include proper
documentation. Proper documentation
includes engineering analyses,
construction drawings and
specifications, and data that address
seal material, fire resistance and flamespread index. The applicant must
establish the materials and materials
properties required for adequate seal
construction. Construction
documentation is required to ensure
that the seals are properly built and
reliable, to address air leakage, and to
verify that the material properties of the
seal will meet the specified strength
criteria.
ETS § 75.336(a)(2)(iv) requires the
application to include an engineering
analysis addressing differences between
actual full-scale test support conditions
and the range of support conditions that
could be encountered in an
underground coal mine. MSHA
recognizes that the test site may have
different support conditions than an
underground coal mine. This
information must ensure that a tested
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seal design will reliably function as
designed in an underground coal mine.
ETS § 75.336(a)(2)(v) requires a Seal
Design Table be included in the
application that discusses
Entry dimensions
(ft)
d. Sec. 75.336(a)(4)
The applicant, under ETS
§ 75.336(a)(4), will be notified by MSHA
in writing, whether the design is
approved or denied. If the design is not
approved, MSHA will specify, again in
writing, the deficiencies of the
application, or necessary revisions for
approval. This provision is consistent
with existing § 77.216–2 and Approval
Policy 1009.
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e. Sec. 75.336(a)(5)
ETS § 75.336(a)(5) is consistent with
existing § 77 .216–3 and requires the
approval holder to promptly contact
MSHA’s Office of Technical Support, in
writing, of all deficiencies, such as
design or material flaws, when they
become aware. MSHA’s intent is that
‘‘promptly’’ means the approval holders
are expected to contact MSHA as soon
as they have knowledge that a
deficiency exists.
f. Sec. 75.336(b) Mine Specific
Application; Seal Design Approval in
the Ventilation Plan
The ETS requires the mine operator to
use an approved seal design, provided
the District Manager approves
installation of the design in the
ventilation plan. The requirements in
this section are consistent with
Procedure Instruction Letter No.
I06–V–9 (August 2006) that established
uniform procedures for application to
MSHA for approval of alternative seals
constructed after July 19, 2006.
ETS § 75.336(b) is new and requires
that mine operators use an MSHAapproved seal design. The mine
ventilation plan that addresses the
19:23 May 21, 2007
Specified unconfined
compressive strength
(psi)
Thickness
(ft-in)
c. Sec. 75.336(a)(3)
ETS § 75.336(a)(3) is consistent with
existing § 77.216(2)(b) and Approval
Policy 1009, and specifies that MSHA
will notify the applicant if additional
information or testing is required. The
applicant must provide this
information, arrange for any additional
or repeat tests related to this additional
information, and notify the Agency of
the location, date, and time of such
tests.
VerDate Aug<31>2005
characteristics related to mine specific
seal construction. These characteristics
include the maximum entry width and
height for which the specific design is
applicable, specified strength of the seal
Jkt 211001
Reinforcement
installation of seals must be approved
by the District Manager prior to the
mine operator initiating seal
construction in the mine. The Darby and
Sago mine explosions revealed
problems with seal construction.
MSHA’s accident investigation report
into both explosions states that the seals
were constructed without mortar
between the joints. MSHA determined
that overpressure was a problem in both
the Sago and Darby accidents. Adequate
seals are crucial to contain explosions
and prevent potentially explosive or
toxic gasses from migrating into the
active working areas of underground
coal mines. MSHA is requiring that seal
installation be approved in the
ventilation plan to help ensure that
seals are appropriately installed to
effectively protect miners.
Under ETS § 75.336(b), the mine
operator must use an approved seal
design provided the installation is
approved in the ventilation plan. These
design documents will serve as
historical references. Seal design
applications must provide information
that the seal will withstand the
appropriate overpressure from an
explosion in accordance with current,
prudent engineering practices, design
codes and guidelines, and the seal
strength requirements of ETS
§ 75.335(a).
ETS § 75.336(b)(1) requires the mine
operator to retain a copy of the seal
design approval information for as long
as the seal is needed to serve the
purpose for which it was built. MSHA
intends to review mine operators’ seal
design approvals at the mine site to
evaluate and address construction and
other installation-related issues.
ETS § 75.336(b)(2) requires the mine
operator to designate a professional
engineer to conduct or have oversight of
seal installation. The professional
engineer is required to certify that the
site-specific seal design complies with
the provisions of paragraph(a) of this
section. The professional engineer will
help ensure that proper seal design
implementation and related analyses are
performed by qualified personnel and
ensure seals are constructed according
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material, thickness of the seal and the
reinforcement and anchorage
requirements for the seal. Additional
information may be provided at the
discretion of the designer.
Foundation anchorage
to the drawings and specifications. A
copy of the certification must be
submitted to the District Manager with
the information provided in ETS
§ 75.336(b)(3). The mine operator must
keep a copy of the certification for as
long as the seal is needed to serve the
purpose for which it was built.
ETS § 75.336(b)(3) lists specific
information that a mine operator must
address in the ventilation plan. This
information will be used by the District
Manager to evaluate a seal installation
and determine whether the seal design
is appropriate for a particular site.
Paragraph (b)(3)(i) requires that mine
operators include the MSHA Technical
Support Approval Number of the seal
design. Paragraph (b)(3)(ii) requires a
mine map certified by a professional
engineer showing the proposed seal
location and surrounding areas to be
submitted.
ETS § 75.336(b)(3)(iii) requires
specific information about the mine site.
This information may be included on
the mine map of the area to be sealed.
Paragraph (b)(3)(iii)(A) requires that the
type of seal be included in the
ventilation plan. The type of seal must
be identified by the approval number
provided in (b)(3)(i) of this paragraph.
ETS § 75.336(b)(3)(iii)(B) requires
mine operators to include safety
precautions to be taken before seals
achieve their specified strength. Safety
precautions could include withdrawing
miners a safe distance from the seal
installation site or actively inerting the
sealed area.
ETS § 75.336(b)(3)(iii)(C) requires that
the mine operator include methods to
address site-specific conditions that
may affect the strength and applicability
of a seal. These conditions could
include: the mine opening dimensions
and an estimate of dimension increases
due to site preparation, such as the
removal of weak roof, floor strata or
friable coal; consideration of the local
geology and mine conditions of the seal
installation location; and a description
of the ground conditions, which may
include anchorage pull-test information.
Other factors such as variability in
material properties, geotechnical
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properties, geologic conditions, and the
quality of construction should be
considered to ensure that a seal can
reliably withstand the overpressures.
Adverse ground conditions, such as
convergence, may be unsuitable for
certain types of seals. These conditions
should be addressed and resolved by the
professional engineer.
ETS § 75.336(b)(3)(iii)(D) requires that
the mine operator specify construction
techniques for each type of seal. This
could include equipment, procedures,
materials and general mine safety
information. This information is
required to help ensure that the seal is
properly constructed.
ETS § 75.336(b)(3)(iii)(E) requires the
mine operator to address seal
construction site preparation which
should include localized mine water
drainage and foundation preparation as
required in each seal design. The
foundation refers to the horizontal and
vertical surfaces of the mine opening.
Keys or hitches formed in rock and coal
to increase the lateral restraint should
be excavated with equipment that
minimizes the fracturing and breakout
of strata. Strata with open joints should
be addressed.
ETS § 75.336(b)(3)(iii)(F) requires the
mine operator to include the sequence
of seal installations. Ventilation controls
should be managed during seal
construction until the final seals are
installed.
ETS § 75.336(b)(3)(iii)(G) requires the
mine operator to provide the projected
completion date of each set of seals.
Changes in ventilation controls may be
necessary as seal construction
progresses and may occur on a daily
basis. MSHA intends for seals to be
installed in a timely manner.
ETS § 75.336(b)(3)(iii)(H) requires the
mine operator to specify supplemental
roof support to be installed inby and
outby each seal. Supplemental support
provides long-term stability for each
seal, and it is important that the Agency
know the type of support used in the
sealed area. The competency of the
strata surrounding the seal is critical to
its long-term stability.
ETS § 75.336(b)(3)(iii)(I) requires the
mine operator to provide an estimation
of the water flow and the dimensions of
the water drainage system. This
information will be used by MSHA to
evaluate whether the water drainage
system is appropriate since seals must
not impound water.
ETS § 75.336(b)(3)(iii)(J) requires the
mine operator to specify the methods
used to ventilate the entries outby the
seals after completion. Ventilation is
necessary to control methane which
outgasses from the sealed area.
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Jkt 211001
Information about the ventilation
methods will help MSHA assess the
adequacy of the ventilation plan.
ETS § 75.336(b)(3)(iii)(K) requires the
mine operator to specify methods and
materials used to maintain each type of
seal. Mine operators should include
information to address minor repair of
cracks, spalls, and small air leaks
through and about the perimeter of each
seal to control leakage. Roof
deterioration, roof falls, and sloughing
of the coal pillars may adversely affect
the overall strength of a seal by
compromising the structural integrity of
the supporting strata.
ETS § 75.336(b)(3)(iii)(L) requires the
mine operator to specify methods to
address shafts and boreholes within the
sealed area. The mine operator should
specify how and when each borehole
will be plugged and each shaft will be
filled during the sealing process.
ETS § 75.336(b)(3)(iii)(M) requires the
mine operator to provide any additional
information requested by the MSHA
District Manager for inclusion in the
ventilation plan. This provision will
ensure that any new developments in
technology or any problems related to
site-specific conditions in sealing may
be addressed by the mine operator
through the ventilation plan.
MSHA requests comments on the
appropriateness of the ventilation plan
contents and whether additional
information should be included.
Commenters should submit information
in support of their positions, including
data related to projected cost and
technological feasibility.
3. Sec. 75.337 Construction and Repair
of Seals
This ETS includes new provision
§ 75.337 addressing requirements for:
preparation of the area to be sealed;
supervision of seal construction and
repair; certification that the seal was
built in accordance with the provisions
in ETS § 75.336(b); notification to
MSHA concerning construction
schedules; and training miners and
senior mine management officials in the
construction and repair of seals. Repairs
addressed by this section are limited to
non-structural repairs. The scope of
these repairs is related to general
maintenance and includes: Excessive air
leakage through and around seals; repair
of minor cracks; spalling of seal coating;
water drainage systems; and sampling
pipes. This section of the ETS is based
on MSHA experience with mine
ventilation plans under existing
§§ 75.334, 75.370, and 75.371, and
regarding worked-out areas and areas
where pillars are being recovered.
MSHA believes these ETS provisions
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28809
are necessary to adequately protect
miners’ health and safety.
a. Sec. 75.337(a)
Site Preparation
ETS § 75.337(a) requires removal of
insulated cables from the area to be
sealed and removal of metallic objects
through or across seals. Paragraph (a)(1)
requires removal of all insulated cables,
including hanging, buried, and cables
within conduit, from the sealed area
before seals are built. This requirement
is included in the ETS because a spark
could be developed if a length of
insulated cable were inductively
coupled to an electromagnetic pulse,
such as those generated by lightning
strikes. These sparks can ignite an
explosive methane/air mixture. After
the SAGO explosion, MSHA contracted
with Sandia Corporation, the operator of
Sandia National Laboratories (Sandia),
to perform modeling and testing to
determine if it were possible for
lightning to cause electrical energy to
enter the Sago Mine and cause an
explosion. Sandia has preliminarily
determined that a lightning strike could
create enough energy in the sealed area
to ignite methane.
Typically, as mine operators complete
mining activities in an area, they
recover the more valuable cables and
may only leave behind damaged or
deteriorated cables. MSHA anticipates
that the removal of abandoned cables
will not be a significant burden for mine
operators and would not adversely
affect future mining activities. This
requirement would improve miners’
safety because removal of cables reduces
the hazard of an explosion caused by an
electrical discharge.
MSHA believes that removal of
insulated cables and metallic objects
through or across seals is feasible and
will not involve significant technical or
practical problems. MSHA solicits
comments on these measures.
ETS § 75.337(a)(2) requires metallic
objects that pass through or across a seal
to be removed. Gas sampling pipes and
water drainage systems required by ETS
§ 75.335(d) and (e), and form ties
approved in the seal design provided by
ETS § 75.336 are allowed in the sealed
area.
Metallic material can provide a
conduit for electrical current to enter
the sealed area and ignite methane/air
mixtures. It is necessary to limit the use
of conductors that may pass around or
across seals. Screen, straps, rails,
channels, and water pipes are typical
metallic materials that are required to be
removed under the ETS. Removal of
metallic objects through or across seals
before they are built will reduce the
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hazard of methane explosions and
improve miner safety.
b. Sec. 75.337(b) Supervision of
Construction and Repair of Seals
ETS § 75.337(b) requires a certified
person designated by the mine operator
to directly supervise the seal
construction and repair process and
make appropriate examinations. After
the Sago Mine and Darby No. 1 Mine
explosions, MSHA inspected seals in
underground coal mines across the
country. The Agency has determined
that some seals were not built correctly.
This new provision requires that seal
construction for all seals built after May
22, 2007 be directly supervised by a
certified person. Existing § 75.100
defines certified person and requires
that person to obtain certification from
the Secretary of Labor or the State in
which the coal mine is located. A
certified person shall directly supervise
the construction of each seal throughout
the construction or repair process. This
new provision will assure that all
activities related to seal construction,
repair, and examination are performed
safely and in accordance with
appropriate requirements.
ETS § 75.337(b)(1) requires a certified
person to examine each seal
construction or repair site prior to
beginning seal construction or repair to
ensure that the site conditions are in
accordance with the approved
ventilation plan.
ETS § 75.337(b)(2) requires a certified
person to observe the construction or
repair process during each shift that
construction or repair take place. This
provision will help ensure construction
or repairs of seals conform to the
approved seal design and site specific
information provided under § 75.336(b).
ETS § 75.337(b)(3) requires a certified
person to perform an examination of
each seal or repair to verify that the seal
or repair is complete. The District
Manager may require that each
examination include an assessment of
any supplemental roof support,
ventilation of the seals, sampling pipes
and appropriate fittings, and the water
drainage system as provided in the
ventilation plan under ETS § 75.336(b).
ETS § 75.337(b)(4) requires the
certified person certify each seal
construction or repair by initialing the
date and time of their examination to
verify that the required examinations
were made.
ETS § 75.337(b)(5) requires a record
be made in a book or a log provided for
that purpose to affirm that the
examinations were conducted. The
record shall describe any deficiencies in
site preparation, such as construction,
repairs, seal completion, and hazardous
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20:26 May 21, 2007
Jkt 211001
conditions and any corrections made.
The record must be made by the
certified person conducting the
examination when the examiner arrives
on the surface at the end of the shift.
The record shall be countersigned by
the mine foreman or equivalent mine
official. Records of the deficiencies and
the corrective actions provide valuable
safety information about seal conditions
and sealed areas in the mine and the
effectiveness of corrective measures.
The recordkeeping requirement for
examination of seals would allow
MSHA to determine if examinations
have been conducted, if results are
valid, and that deficiencies in site
preparation, construction, repairs, and
seal completion found were corrected.
By requiring that a record be
countersigned, MSHA expects that the
mine foreman or equivalent mine
official must review the record before
countersigning. This provision makes
certain that a mine foreman or
equivalent mine official is responsible
for oversight of seal installation. The
countersignature shall be made by the
end of the mine foreman’s or equivalent
mine official’s next regularly scheduled
working shift.
The records of examinations required
under ETS § 75.337(b)(5) shall be kept at
the mine for one year. ETS § 75.338 sets
out additional seal recordkeeping
duration requirements.
c. Sec. 75.337(c) Certification of
Construction by Senior Mine
Management
ETS § 75.337(c) requires that upon
completion of construction of each seal,
a senior mine management official, such
as a mine manager or superintendent,
certify that the construction,
installation, and materials used were in
accordance with the approved mine
ventilation plan. This requirement
assures that a senior mine management
official takes responsibility for making
sure that seals are constructed in
accordance with the provisions under
ETS § 75.336(b).
d. Sec. 75.337(d) Notification to
MSHA
ETS § 75.337(d)(1) requires the mine
operator to notify the local MSHA field
office between two and fourteen days
prior to commencement of seal
construction. This requirement provides
MSHA the opportunity to observe seal
construction. This is particularly critical
when a mine operator is installing a
new seal design or the mine liberates
large amounts of methane.
ETS § 75.337(d)(2) requires the mine
operator to notify the MSHA District
Manager, in writing, within 5 days of
completion of each set of approved
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seals. This provision allows the District
Manager to be informed when all
construction is completed. This is a
critical time period during the
construction of seals. It involves the
time period during which seals are
achieving full strength and the
atmosphere inby the seals may be
transitioning into or through a
potentially explosive methane/air
mixture. MSHA may decide to inspect
the newly sealed area, or sample the
atmosphere.
ETS § 75.337(d)(3) requires the mine
operator to submit to the MSHA District
Manager quality control test results
required in ETS § 75.336. Material test
results shall be sent to MSHA and must
include all seal testing and tests of seal
construction materials.
e. Sec. 75.337(e) Training
Failure of a seal may result in
significant injury, loss of life and/or
significant economic loss. Based on
recent explosion investigations, MSHA
learned that numerous persons involved
in constructing seals that failed were not
adequately trained. As a result,
installation, construction, and repair
tasks and the level of quality control
exercised during these activities are
critical to preventing seal failures and
protecting miners.
Under ETS § 75.337(e), the mine
operator is responsible for providing
training to miners constructing or
repairing seals, certified persons
supervising seal construction, repair,
and examinations described in (b)(1) of
this section, and senior mine
management officials described in
paragraph (c) of this section.
The training shall address materials
and procedures required in the
approved seal design in the mine’s
ventilation plan. For example, material
training could include how to construct
reinforced concrete, masonry block,
gunite, and cementitious foam seals.
Additionally, training shall include
procedures in tasks such as hitching,
evacuating weak materials, supporting
and stabilizing roofs, and installing
sampling pipes and water drainage
systems.
Training under this paragraph is also
required for persons repairing seals. In
addition to the training required for
constructing seals, further training may
be necessary for repairing a damaged
seal. This training could include tasks
such as patching small cracks, sealing
leaks, and maintaining water drainage
systems.
MSHA recognizes that the amount of
time required for training in
constructing or repairing seals will vary.
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For this reason, MSHA is not proposing
a minimum amount of time for the
training. MSHA expects mine operators
to adjust the time for this training based
on the complexity of the seal design in
the ventilation plan, construction or
repair procedures, materials used, and
existing knowledge and skill levels of
persons receiving the training. Also,
changes in the approved seal design or
approved ventilation plan will require
retraining.
This paragraph also requires mine
operators to certify the date that training
was provided. Operators are required to
retain these certifications for one year
from the time training was conducted.
This provision is similar to other
certification requirements in Part 75
where the operator certifies by signature
and date that training was provided.
MSHA requests comments on the
provisions provided in this section. In
particular, MSHA requests comments
concerning the scope and possible
alternatives to the requirements related
to site preparation, examinations, and
notification provisions.
28811
4. Sec. 75.338 Seals Records
ETS § 75.338(a) sets out the
recordkeeping duration required for
records created under ETS §§ 75.335,
75.336, and 75.337. For the convenience
of the mining community, these
requirements are listed in the table
entitled ‘‘Table § 75.338(a) Seal
Recordkeeping Requirements.’’ The
table lists the record which must be
kept, the section requiring the record,
and the required retention time.
TABLE TO § 75.338(a). SEAL RECORDKEEPING REQUIREMENTS
Record
Section reference
(1) Protocol to monitor methane and oxygen and maintain an
inert atmosphere.
(2) Training of certified persons ................................................
(3) Gas sampling records ..........................................................
(4) Approved seal design ..........................................................
75.335(b) ..........
Same as ventilation plan requirements.
75.335(b)(2) ......
75.335(b)(6) ......
75.336(b)(1) ......
(5) Certification of provisions of approved seal design is addressed.
(6) Record of examinations .......................................................
(7) Seal construction certification ..............................................
75.336(b)(2) ......
(8) Certification of training .........................................................
75.337(e) ..........
1 year.
1 year.
As long as the seal is needed to serve the purpose for which
it is built.
As long as the seal is needed to serve the purpose for which
it is built.
1 year.
As long as the seal is needed to serve the purpose for which
it is built.
1 year.
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ETS § 75.338(b) applies to seal records
required to be kept under the ETS,
except for the certification required
under ETS § 75.337(b)(4) which must be
retained at the seal site. Operators must
retain records at the mine site. The mine
operator may retain records in a
computer system elsewhere, provided
they are immediately accessible from
the mine site by electronic transmission.
Records must be secure and not subject
to alteration.
ETS § 75.338(c) requires that the
operator allow access to any record to
an authorized representative of the
Secretary of Labor, the Secretary of
Health and Human Services, the
authorized representative of miners, or
other interested parties, upon request.
Mine operators are to promptly provide
access to any record listed in the table
in paragraph (a) of this section. MSHA
expects that an operator show due
diligence in providing access to
required records. Whenever an operator
ceases to do business, the operator will
be required to transfer all records
required to be maintained by this part
to any successor operator.
5. Conforming Changes to Other
Sections in Part 75
Existing paragraph (ff) of § 75.371
requires the mine operator to provide a
description of methods and materials to
be used to seal worked out areas when
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75.337(b)(5) ......
75.337(c) ..........
Retention time
they are different from those specified
in paragraph (a)(1) of § 75.335. The
provisions in existing paragraph (a) of
§ 75.335 are revised and moved to
paragraph (b) of § 75.335 and paragraph
(b)(3) of § 75.336. Therefore, paragraph
(ff) is revised to reference sampling
requirements provided by paragraph (b)
of § 75.335 and ventilation plan
contents requirements provided by
paragraph (b)(3) of § 75.336.
V. Executive Order 12866
Executive Order (E.O.) 12866 (58 FR
51735) as amended by E.O. 13258
(Amending Executive Order 12866 on
Regulatory Planning and Review (67 FR
9385)) requires regulatory agencies to
assess both the costs and benefits of
regulations. To comply with Executive
Order 12866, MSHA has prepared a
Regulatory Economic Analysis (REA) for
the ETS. The REA contains supporting
data and explanation for the summary
materials presented in sections V–IX of
this preamble, including the covered
mining industry, costs and benefits,
feasibility, small business impact, and
paperwork. The REA is located on
MSHA’s Web site at https://
www.msha.gov/regsinfo.htm. A copy of
the REA can be obtained from MSHA’s
Office of Standards, Regulations and
Variances. MSHA requests comments on
all the estimates of costs and benefits
presented in this ETS and in the REA.
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MSHA has determined that the ETS
would not have an annual effect of $100
million or more on the economy and,
therefore, it is not an economically
‘‘significant regulatory action’’ pursuant
to Sec. 2(f) of E.O. 12866.
A. Population-at-Risk
The ETS applies to all underground
coal mines in the United States. Based
on preliminary MSHA data, there were
670 underground coal mines, employing
42,667 miners, operating in the U.S. in
2006. Of these, 372 underground coal
mines use seals. These 372 mines
employ 33,684 miners, of which 30,095
work underground.
B. Benefits
To provide a preliminary quantitative
estimate of benefits, MSHA analyzed the
explosions in sealed areas that have
taken place since 1993, and especially
studied the two accidents in 2006 where
the seals failed and fatalities occurred:
the Sago mine explosion, where 12
miners died, and the Darby No. 1 mine
explosion, where 5 miners died. It is
reasonable to assume that if the ETS had
been in effect, all 17 of these miners’
lives might have been saved. Fourteen
of these lives might have been saved by
the 2006 ETS and final rule on
emergency mine evacuation. However,
three of the miners that perished in the
Sago and Darby accidents died
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immediately from the explosion impact.
They could not have been saved by the
emergency mine evacuation rule. For
purposes of estimating benefits, MSHA
attributes the saving of three miners’
lives to this ETS and splits the
remaining 14 lives between this ETS
and the 2006 emergency mine
evacuation rule. Hence, MSHA
attributes the saving of 10 lives to this
ETS (3 + (14 ÷ 2) = 10).
MSHA has good data on explosions in
sealed areas only since 1993. During the
period 1993–2006 (14 years) there were
13 explosions in sealed areas. However,
only 11 of these explosions caused any
seal damage and thus had the potential
to cause fatalities or injuries. Only two
of these 11 explosions actually caused
fatalities or injuries. A strict division,
(10 lives)/(14 years), would suggest that
the ETS will save approximately 0.7
lives per year if the explosions followed
approximately the same distribution as
they did since 1993.
However, MSHA believes that the risk
from explosions in sealed areas has been
increasing during this time period
because the number of seals has been
increasing. MSHA did not allow
alternative seals until 1992. Prior to
1992, most mines did not seal, but
instead ventilated. During the period
from 1993 through 2006, mines went
through a transition period of shifting
from ventilation to seals. The current
risk from explosions in sealed areas is
therefore higher than the historic risk
during this transition period.
MSHA roughly estimates that, on
average, during that transition period,
the number of mines using seals was no
more than 2⁄3 of the number of mines
that currently use seals. Furthermore,
the number of seals in mines is
cumulative. During this period of
increased seal use, MSHA roughly
estimates that the average number of
seals in mines that used seals was no
more than 2/3 of the number in mines
that currently use seals. MSHA
specifically asks for comment on these
estimates. After adjusting this estimate
to account for the increased future risk,
the ETS will save approximately 1.6
lives per year, since (10⁄14/2⁄3/2⁄3) = 1.6.
This is MSHA’s best estimate on the
number of lives saved per year due to
this rulemaking.
MSHA also developed a higher risk
estimate, based primarily on the
distribution of miners put at risk and
the characteristics of the explosions
themselves. MSHA also asks for
comment on these calculations.
In the 11 explosions in sealed areas
with property damage, approximately
688 miners total were underground at
the time of the explosions. This is an
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average of 62.5 miners per explosion
that were put at risk. In the two
explosions at Sago and Darby only a
total of 35 miners were underground at
the time of the explosions, for an
average risk exposure of 17.5 miners per
explosion. Fortunately, no explosions in
sealed areas at larger mines (so far) have
caused any injuries or fatalities.
If an explosion with the
characteristics of the explosions at Sago
or Darby occurs at a larger mine, many
more lives potentially could be lost.
Assuming the risk of fatality from an
explosion in a sealed area is about the
same at both large and small mines, and
the number of potential fatalities is
proportional to the number of miners
working underground, during the other
explosions studied by MSHA, then a
higher risk estimate of the benefits of
the ETS is approximately 5.7 lives saved
per year, since 1.6 x (62.5/17.5) = 5.7.
MSHA also calculated the cumulative
risk faced by a miner over a 45 year
working life. The 372 existing
underground coal mines that seal
employ 33,684 miners; of these, 30,095
work underground. Under MSHA’s best
estimate, the ETS will save 1.6 lives per
year, which means that the risk of
fatality per year per 1,000 miners is
0.053. Over a 45-year working lifetime,
the risk of fatality from an explosion in
a sealed area is 2.4 per 1,000 miners. If
the ETS will save the higher estimate of
benefits of 5.7 lives per year, then the
risk of fatality per year per 1,000 miners
is 0.191. Over a 45-year working
lifetime, the risk of fatality from an
explosion in a sealed area is 8.5 per
1,000 miners.
With the provisions of the ETS in
effect, an explosion is less likely to
occur behind seals that are being
actively monitored to maintain an inert
atmosphere. The provisions of the ETS
also strengthen seals to better withstand
explosions, which reduces immediate
miner injuries and fatalities and gives
miners more time to react to a situation
involving an explosion.
MSHA requests comments on the
benefit estimates developed above and
in the REA, as well as on the
assumptions and data sources that
MSHA used.
C. Compliance Costs
MSHA estimates that the ETS will
result in total yearly costs for
underground mine operators and
contractors of approximately $39.7
million. Total first year costs will be
approximately $43.2 million.
Disaggregated by mine size, yearly costs
will be $2.6 million for the 83 mine
operators with fewer than 20 employees;
$34.7 million for the 279 mine operators
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with 20–500 employees; and $2.4
million for the 10 mine operators with
more than 500 employees. Most of the
compliance cost occurs in the mine size
category with 20–500 employees
because 75 percent of the mines that use
seals are in this category.
MSHA requests comments on the cost
estimates developed above and in the
REA, as well as on the assumptions and
data sources that MSHA used.
VI. Feasibility
MSHA has concluded that the
requirements of the ETS are
technologically and economically
feasible.
A. Technological Feasibility
MSHA concludes that the ETS is
technologically feasible. MSHA based
its conclusion on an analysis of the
compliance requirements of the ETS
provisions for training, sampling, and
construction and repair. MSHA believes
compliance with these requirements is
technologically feasible because the
materials, equipment, and methods for
implementing these requirements
currently exist. However, MSHA will be
gathering information on seal designs at
120 psi overpressure and will make this
information available to the mining
community. MSHA solicits comments
on this issue, and on seal designs that
are greater than 120 psi overpressure.
B. Economic Feasibility
MSHA also believes that the ETS is
economically feasible. The yearly
compliance cost of the ETS is $39.7
million which is 0.30 percent of all
revenues ($39.7 million/$13.1 billion)
for all underground coal mines. MSHA
concludes that the ETS is economically
feasible for these mine operators
because the total compliance costs are
well below one percent of the estimated
revenues for all underground coal
mines.
VII. Regulatory Flexibility Act and
Small Business Regulatory Enforcement
Fairness Act (SBREFA)
Pursuant to the Regulatory Flexibility
Act (RFA) of 1980, as amended by the
Small Business Regulatory Enforcement
Fairness Act (SBREFA), MSHA has
analyzed the impact of the ETS on small
businesses. Based on that analysis,
MSHA has notified the Chief Counsel
for Advocacy, Small Business
Administration, and made the
certification under the Regulatory
Flexibility Act at 5 U.S.C. 605(b) that
the ETS will not have a significant
economic impact on a substantial
number of small entities. The factual
basis for this certification is presented
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in full in Chapter V of the REA and in
summary form below.
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A. Definition of a Small Mine
Under the RFA, in analyzing the
impact of the ETS on small entities,
MSHA must use the Small Business
Administration (SBA) definition for a
small entity or, after consultation with
the SBA Office of Advocacy, establish
an alternative definition for the mining
industry by publishing that definition in
the Federal Register for notice and
comment. MSHA has not taken such an
action and hence is required to use the
SBA definition. The SBA defines a
small entity in the mining industry as
an establishment with 500 or fewer
employees.
In addition to examining small
entities as defined by SBA, MSHA has
also looked at the impact of this ETS on
underground coal mines with fewer
than 20 employees, which MSHA and
the mining community have
traditionally referred to as ‘‘small
mines.’’ These small mines differ from
larger mines not only in the number of
employees, but also in economies of
scale in material produced, in the type
and amount of production equipment,
and in supply inventory. Therefore, the
cost of complying with MSHA’s ETS
and the impact of the ETS on small
mines will also be different. It is for this
reason that small mines are of special
concern to MSHA.
MSHA concludes that it can certify
that the ETS will not have a significant
economic impact on a substantial
number of small entities that are
covered by this ETS. The Agency has
determined that this is the case both for
mines with fewer than 20 employees
and for mines with 500 or fewer
employees.
B. Factual Basis for Certification
MSHA initially evaluates the impacts
on ‘‘small entities’’ by comparing the
estimated compliance costs of a rule for
small entities in the sector affected by
the rule to the estimated revenues for
the affected sector. When estimated
compliance costs are less than one
percent of the estimated revenues, the
Agency believes it is generally
appropriate to conclude that there is no
significant economic impact on a
substantial number of small entities.
When estimated compliance costs
exceed one percent of revenues, MSHA
investigates whether a further analysis
is required.
For underground coal mines, the
estimated 2006 production was
7,813,073 tons for mines that had fewer
than 20 employees and 277,500,019 tons
for mines that had 500 or fewer
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employees. Using the 2005 price of
underground coal of $36.42 per ton 2
and total 2006 coal production in tons,
underground coal revenues are
estimated to be approximately $285
million for mines employing fewer than
20 employees and $10.1 billion for
mines employing 500 or fewer
employees. Thus, the yearly cost of the
ETS for mines that have fewer than 20
employees is 0.9 percent ($2.6 million/
$285 million) of annual revenues, and
the yearly cost of the ETS for mines that
have 500 or fewer employees is 0.4
percent ($0.037 billion/$10.1 billion) of
annual revenues. Using either MSHA’s
traditional definition of a small mine
(one having fewer than 20 employees) or
SBA’s definition of a small mine (one
having 500 or fewer employees), the
yearly costs for underground coal mines
to comply with the ETS will be less than
1 percent of their estimated revenues.
Accordingly, MSHA has certified that
the ETS will not have a significant
impact on a substantial number of small
entities that are covered by the ETS.
VIII. Paperwork Reduction Act of 1995
A. Summary
This ETS contains information
collection requirements that MSHA
estimates will result in 82,037 new
burden hours and approximately $4.7
million related burden costs to mine
operators and manufacturers in the first
year that the ETS is in effect. In the
second year that the ETS is in effect,
and for every year thereafter, MSHA
estimates that mine operators and
manufacturers will incur 73,006 new
burden hours and approximately $4.6
million related burden costs. The
burden is different in the first year
because some information collection
requirements occur only in the first year
that the ETS is in effect.
This ETS contains information
collection requirements in the following
sections: § 75.335 seal requirements;
§ 75.336 seal design applications and
installation approval; and § 75.337
construction and repair.
For a detailed explanation of how the
burden hours and related costs were
determined, see Chapter VII of the
Regulatory Economic Analysis (REA)
associated with this ETS. The REA is
located on MSHA’s Web site at https://
www.msha.gov/REGSINFO.HTM. A
print copy of the REA can be obtained
from the Office of Standards,
Regulations, and Variances at MSHA.
B. Details
The information collection package
has been submitted to the Office of
Management and Budget (OMB) for
review under 44 U.S.C. § 3504(h) of the
Paperwork Reduction Act of 1995, as
amended. A copy of the information
collection package can be obtained from
the Department of Labor by email
request to king.darrin@dol.gov or by
phone request at (202) 693–4129.
Comments on the provisions in the
information collection requirements
should be sent to both the Office of
Information and Regulatory Affairs of
OMB and to MSHA. Comments sent to
OMB should be sent to the Attention of
the Desk Officer for the Mine Safety and
Health Administration. Comments sent
to MSHA should be sent to the Office of
Standards, Regulations, and Variances.
Addresses for both offices can be found
in the Addresses section of this
preamble. Respondents are not required
to respond to any collection of
information unless it displays a current
valid OMB control number. MSHA will
publish a notice in the Federal Register
announcing when OMB has approved
the new information collection
requirements.
IX. Other Regulatory Considerations
A. The Unfunded Mandates Reform Act
of 1995
MSHA has reviewed the ETS under
the Unfunded Mandates Reform Act of
1995 (2 U.S.C. 1501 et seq). MSHA has
determined that this ETS does not
include any federal mandate that may
result in increased expenditures by
State, local, or tribal governments; nor
will it increase private sector
expenditures by more than $100 million
in any one year or significantly or
uniquely affect small governments.
Accordingly, the Unfunded Mandates
Reform Act of 1995 (2 U.S.C. 1501 et
seq.) requires no further agency action
or analysis.
B. Executive Order 13132: Federalism
This ETS does not have ‘‘federalism
implications’’ because it will not ‘‘have
substantial direct effects on the States,
on the relationship between the national
government and the States, or on the
distribution of power and
responsibilities among the various
levels of government.’’ Accordingly,
under E.O. 13132, no further Agency
action or analysis is required.
2 U.S. Department of Energy, Energy Information
Administration, Annual Coal Report 2005, Table 28.
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C. The Treasury and General
Government Appropriations Act of
1999: Assessment of Federal
Regulations and Policies on Families
Section 654 of the Treasury and
General Government Appropriations
Act of 1999 (5 U.S.C. 601 note) requires
agencies to assess the impact of Agency
action on family well-being. MSHA has
determined that this ETS will have no
effect on family stability or safety,
marital commitment, parental rights and
authority, or income or poverty of
families and children. This ETS impacts
only the underground coal mine
industry. Accordingly, MSHA certifies
that this ETS would not impact family
well-being.
D. Executive Order 12630: Government
Actions and Interference With
Constitutionally Protected Property
Rights
This ETS does not implement a policy
with takings implications. Accordingly,
under E.O. 12630, no further Agency
action or analysis is required.
E. Executive Order 12988: Civil Justice
Reform
This ETS was written to provide a
clear legal standard for affected conduct
and was carefully reviewed to eliminate
drafting errors and ambiguities, so as to
minimize litigation and undue burden
on the Federal court system.
Accordingly, this ETS will meet the
applicable standards provided in
section 3 of E.O. 12988, Civil Justice
Reform.
F. Executive Order 13045: Protection of
Children From Environmental Health
Risks and Safety Risks
This ETS will have no adverse impact
on children. Accordingly, under E.O.
13045, no further Agency action or
analysis is required.
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G. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
This ETS does not have ‘‘tribal
implications’’ because it will not ‘‘have
substantial direct effects on one or more
Indian tribes, on the relationship
between the Federal government and
Indian tribes, or on the distribution of
power and responsibilities between the
Federal government and Indian tribes.’’
Accordingly, under E.O. 13175, no
further Agency action or analysis is
required.
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H. Executive Order 13211: Actions
Concerning Regulations That
Significantly Affect Energy Supply,
Distribution, or Use
Executive Order 13211 requires
agencies to publish a statement of
energy effects when a rule has a
significant energy action that adversely
affects energy supply, distribution or
use. MSHA has reviewed this ETS for its
energy effects because the ETS applies
to the underground mining sector.
Because this ETS will result in yearly
costs of approximately $39.7 million to
the underground coal mining industry,
relative to annual revenues of $13.1
billion in 2006, MSHA has concluded
that it is not a significant energy action
because it is not likely to have a
significant adverse effect on the supply,
distribution, or use of energy.
Accordingly, under this analysis, no
further Agency action or analysis is
required.
X. References
ACI 318–05, ‘‘Building Code Requirements
for Structural Concrete and
Commentary,’’ American Concrete
Institute.
ACI 440.2R–02, ‘‘Design and Construction of
Externally Bonded FRP Systems for
Strengthening Concrete Structures,’’
American Concrete Institute.
Army TM 5–1300, Navy NAVFAC P0397, Air
Force AFR 88–22, Departments of the
Army, the Navy, and the Air Force,
‘‘Structures to Resist the Effects of
Accidental Explosions,’’ November 1990.
ASTM E119–07, ‘‘Standard Test Methods for
Fire Tests of Building Construction and
Materials,’’ ASTM International.
ASTM E162–06, ‘‘Surface Flammability of
Materials Using a Radiant Heat Energy
Source,’’ ASTM International.
Department of Labor, Mine Safety and Health
Administration, Final Rule,
Underground Coal Mine Ventilation
Standards, May 15, 1992.
Kissell, Fred N., ‘‘Handbook for Methane
Control in Mining,’’ Information Circular
9486. National Institute of Occupational
Safety and Health, U.S. Dept. of Health
and Human Services, 2006.
Mitchell, Donald W., ‘‘Explosion-Proof
Bulkheads—Present Practices,’’ Report of
Investigations No. 7581, U.S. Dept. of the
Interior, Bureau of Mines, 1971.
Mitchell, Donald W., Burns, Frank A.,
‘‘Interpreting the State of a Mine Fire,’’
Investigational Report No. 1103, U.S.
Department of Labor, Mine Safety and
Health Administration, 1979.
MSHA. Report of Investigation/Mine
Explosion, Sago Mine, January 2, 2006.
MSHA. Report of Investigation/Mine
Explosion, Darby Mine No. 1, May 20,
2006.
MSHA. Program Information Bulletin No.
P06–11, ‘‘Moratorium on Future Use of
Alternative Seal Methods and Materials
Pursuant to 30 CFR 75.335 and
Assessment of Existing Sealed Areas in
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Underground Bituminous Coal Mines,’’
June 1, 2006.
MSHA. Program Information Bulletin No.
P06–12, ‘‘Reissued Moratorium on
Future Use of Alternative Seal Methods
and Materials Pursuant to 30 CFR 75.335
and Assessment of Existing Sealed Areas
in Underground Bituminous Coal
Mines,’’ June 12, 2006.
MSHA. Program Information Bulletin No.
P06–16, ‘‘Use of Alternative Seal
Methods and Materials Pursuant to 30
CFR 75.335(a)(2),’’ July 19, 2006.
MSHA. Procedure Instruction Letter No. I06–
V–9, ‘‘Procedures for Approval of
Alternative Seals,’’ August 21, 2006.
MSHA. Program Policy Manual, Volume V–
Coal Mines, Release V–33, February
2003.
MSHA, Approval and Certification Center,
Application Cancellation Policy, CDS
No. APOL1009, Revised February 27,
2004.
Zipf, R. K., Sapko, M. J., Brune, J. F.,
‘‘Explosion Pressure Design Criteria for
New Seals in U.S. Coal Mines, Draft
Report,’’ National Institute of
Occupational Safety and Health, U.S.
Dept. of Health and Human Services,
February 8, 2007.
XI. Emergency Temporary Standard—
Regulatory Text
List of Subjects in 30 CFR Part 75
Mine safety and health, Underground
coal mines, Reporting and
recordkeeping, Ventilation.
Dated: May 17, 2007.
Richard E. Stickler,
Assistant Secretary for Mine Safety and
Health.
Chapter I of Title 30, part 75 of the
Code of Federal Regulations is amended
as follows:
I
PART 75—SAFETY STANDARDS FOR
UNDERGROUND COAL MINES
1. The authority citation for part 75
continues to read as follows:
I
Authority: 30 U.S.C. 811, 863.
I
2. Revise § 75.335 to read as follows:
§ 75.335
Seal requirements.
Seals shall be designed, constructed,
and maintained to protect miners from
hazards related to sealed areas. Seal
designs and the installation of each seal
shall be approved in accordance with
§ 75.336.
(a) Seal strength requirements. Seals
constructed on or after May 22, 2007
shall be designed, constructed, and
maintained to withstand—
(1) 50 psi overpressure when the
atmosphere in the sealed area is
monitored and maintained inert in
accordance with paragraph (b) of this
section;
(2) 120 psi overpressure if the
atmosphere is not monitored, and is not
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maintained inert, and the conditions in
paragraphs (a)(3)(i) through (iii) of this
section are not present; or
(3) An overpressure greater than 120
psi if the atmosphere is not monitored
and is not maintained inert and;
(i) The atmosphere in the area to be
sealed is likely to contain homogeneous
mixtures of methane between 4.5
percent and 17.0 percent and oxygen
exceeding 17.0 percent throughout the
entire area;
(ii) Pressure piling is likely due to
opening restrictions near the proposed
seal area; or
(iii) Other conditions are encountered,
such as the likelihood of a detonation in
the proposed seal area.
(iv) Where the conditions in
paragraphs (a)(3)(i), (ii), or (iii) of this
section are encountered, the operator
must revise the ventilation plan to be
submitted to the District Manager to
address the potential hazards. The plan
shall include seal strength sufficient to
address the conditions.
(b) Sampling and monitoring
requirements. Effective May 22, 2007, a
certified person as defined in § 75.100
shall monitor atmospheres of sealed
areas. For seals constructed prior to May
22, 2007 and for seals designed for 50
psi overpressure, mine operators shall
develop and follow a protocol to
monitor methane and oxygen
concentrations, and to maintain an inert
atmosphere in the sealed area. The
protocol shall be approved in the
ventilation plan.
(1) A certified person shall sample
atmospheres of sealed areas weekly
when the barometric pressure is
decreasing or the seal is outgassing. At
least one sample shall be taken at each
set of seals. If a seal is ingassing during
the weekly examination, a sample shall
be collected during the next weekly
examination. If the seal is ingassing
during the second consecutive weekly
examination, the operator shall examine
that seal daily until the seal is
outgassing, unless the seal does not
outgas. In this case, an alternative plan
needs to be developed and submitted to
the District Manager. The District
Manager may approve different
sampling frequencies and locations in
the ventilation plan, or approve the use
of atmospheric monitoring systems in
lieu of weekly sampling. The mine
operator shall revise the protocol, if
repeated sampling indicates that a seal
is not likely to outgas.
(2) Certified persons conducting
sampling shall be trained in the
sampling procedures included in the
protocol, as provided by paragraph
(b)(5) of this section, before they
conduct sampling, and annually
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thereafter. The mine operator must
certify the date and content of training
provided certified persons and retain
each certification for one year.
(3) The atmosphere shall be
considered inert when—
(i) The oxygen concentration is less
than 10.0 percent;
(ii) The methane concentration is less
than 3.0 percent; or
(iii) The methane concentration is
greater than 20.0 percent.
(4) When oxygen concentrations are
10.0 percent or greater and methane
concentrations are from 3.0 percent to
20.0 percent in a sealed area, the mine
operator shall take two additional gas
samples at one-hour intervals. If the two
additional gas samples are from 3.0
percent to 20.0 percent and oxygen is
10.0 percent or greater—
(i) The mine operator shall implement
the action plan in the protocol; or
(ii) Persons shall be withdrawn from
the affected area, except those persons
referred to in section 104(c) of the Act.
(5) The protocol shall address—
(i) Sampling procedures, including
equipment and methods to be used;
(ii) Location of sampling points;
(iii) Procedures to establish a baseline
analysis of oxygen and methane
concentrations at each sampling point
over a 14-day sampling period. The
baseline shall be established after the
atmosphere in the sealed area becomes
inert or the trend reaches equilibrium;
(iv) Frequency of sampling;
(v) Size and conditions of the sealed
area; and
(vi) Use of atmospheric monitoring
systems, where applicable;
(vii) The protocol shall include an
action plan that addresses the hazards
presented and actions taken when gas
samples indicate oxygen concentrations
of 10.0 percent or greater for each of the
following ranges of methane
concentrations—
(A) 3.0 percent or greater but less than
4.5 percent; and
(B) 4.5 percent or greater but less than
17.0 percent; and
(C) 17.0 percent to 20 percent.
(6) The certified person shall
promptly record each sampling result,
including the location of the sampling
points, and oxygen and methane
concentrations. The results of oxygen
and methane samples shall be recorded
as the percentage of oxygen and
methane measured by the certified
person and any hazardous condition
found, in accordance with § 75.363.
(7) The mine operator shall retain
sampling records at the mine for at least
one year from the date of sampling.
(c) Welding, cutting, and soldering
with an arc or flame are prohibited
within 150 feet of a seal.
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(d) For seals constructed after May 22,
2007, at least two sampling pipes shall
be installed in each seal. One pipe shall
extend approximately 15 feet into the
sealed area and another shall extend
into the center of the first connecting
crosscut inby the seal. Each sampling
pipe shall be equipped with a shut-off
valve and appropriate fittings for taking
gas samples.
(e) For each set of seals constructed
after May 22, 2007, the seal at the lowest
elevation shall have a corrosionresistant water drainage system. Seals
shall not impound water.
I 3. Add § 75.336 to read as follows:
§ 75.336 Seal design applications and
installation approval.
(a) Seal design applications from seal
manufacturers or mine operators shall
be in accordance with paragraphs (a)(1)
or (a)(2) of this section and submitted
for approval to MSHA’s Office of
Technical Support, Pittsburgh Safety
and Health Technology Center, P.O. Box
18233, Cochrans Mill Road, Pittsburgh,
PA 15236.
(1) An engineering design application
shall:
(i) Address gas sampling pipes, water
drainage systems, air leakage, fire
resistance, flame spread index, pressuretime curve, entry size, engineering
design and analysis, material properties,
construction specifications, quality
control, design references, and other
information related to seal construction;
(ii) Be certified by a professional
engineer that the design of the seal is in
accordance with current, prudent
engineering practices; and
(iii) Include a Seal Design Table that
discusses characteristics related to
mine-specific seal construction.
(2) Each application based on fullscale explosion tests shall address the
following requirements to ensure that a
seal can reliably withstand the
overpressures provided by § 75.335:
(i) Certification by a professional
engineer knowledgeable in structural
engineering that the testing was done in
accordance with current, prudent
engineering practices and its
applicability in a coal mine;
(ii) Technical information related to
the methods and materials;
(iii) Proper documentation;
(iv) An engineering analysis to
address differences between the seal
support during test conditions and the
range of conditions in a coal mine; and
(v) The application shall include a
Seal Design Table that discusses
characteristics related to mine specific
seal construction.
(3) MSHA will notify the applicant if
additional information or testing is
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required. The applicant must provide
this information, arrange any additional
or repeat tests, and notify MSHA of the
location, date, and time of the test(s).
(4) MSHA will notify the applicant, in
writing, whether the design is approved
or denied. If the design is not approved,
MSHA will specify, in writing, the
deficiencies of the application, or
necessary revisions.
(5) Once the seal design is approved,
the approval holder must promptly
notify MSHA, in writing, of all
deficiencies of which they become
aware.
(b) The mine operator shall use an
approved seal design provided its
installation is approved in the
ventilation plan. The mine operator
shall—
(1) Retain the seal design approval
information for as long as the seal is
needed to serve the purpose for which
it was built.
(2) Designate a professional engineer
to conduct or have oversight of seal
installation and certify that the
provisions in the approved seal design
specified in paragraph (a) of this section
have been addressed. A copy of the
certification shall be submitted to the
District Manager with the information
provided in § 75.336(b)(3) and a copy of
the certification shall be retained for as
long as the seal is needed to serve the
purpose for which it was built.
(3) Provide information for approval
in the ventilation plan—
(i) The MSHA Technical Support
Approval Number;
(ii) The mine map of the area to be
sealed and proposed seal locations. This
portion of the mine map shall be
certified by a professional engineer;
(iii) Specific mine site information,
including’
(A) Type of seal;
(B) Safety precautions taken prior to
seal achieving full design strength;
(C) Methods to address site specific
conditions that may affect the strength
and applicability of the seal;
(D) The construction techniques;
(E) Site preparation;
(F) Sequence of seal installations;
(G) Projected date of completion of
each set of seals;
(H) Supplemental roof support inby
and outby each seal;
(I) Water flow estimation and
dimensions of the water drainage
system through the seals;
(J) Methods to ventilate the outby face
of seals once completed;
(K) Methods and materials used to
maintain each type of seal;
(L) Methods to address shafts and
boreholes in the sealed area; and
(M) Additional information required
by the District Manager.
I 4. Add § 75.337 to read as follows:
§ 75.337
Construction and repair of seals.
(a) Prior to sealing, the mine operator
shall—
(1) Remove insulated cables from the
area to be sealed when constructing
seals; and
(2) Remove metallic objects through
or across seals, except water pipes, gas
sampling pipes, and form ties approved
in the seal design.
(b) A certified person designated by
the mine operator shall directly
supervise seal construction and repair
and—
(1) Examine each seal site
immediately prior to construction or
repair to ensure that the site is in
accordance with the approved
ventilation plan;
(2) Examine each seal under
construction or repair during each shift
to ensure that the seal is being
constructed or repaired in accordance
with the approved ventilation plan;
(3) Examine each seal upon
completion of construction or repair to
ensure that construction or repair is in
accordance with the approved
ventilation plan;
(4) Certify by initials, date, and time
that the examinations were made; and
(5) Make a record of the examination
at the completion of any shift during
which an examination was conducted.
The record shall include each
deficiency and the corrective action
taken. The record shall be countersigned
by the mine foreman or equivalent mine
official by the end of the mine foreman’s
or equivalent mine official’s next
regularly scheduled working shift. The
record shall be kept at the mine for one
year.
(c) Upon completion of construction
of each seal, a senior mine management
official, such as a mine manager or
superintendent, shall certify that the
construction, installation, and materials
used were in accordance with the
approved ventilation plan. The mine
operator shall retain the certification for
as long as the seal is needed to serve the
purpose for which it was built.
(d) The mine operator shall—
(1) Notify the local MSHA field office
between two and fourteen days prior to
commencement of seal construction;
(2) Notify the District Manager, in
writing, within five days of completion
of a set of seals; and
(3) Submit a copy of quality control
results to the District Manager for seal
material properties specified by
§ 75.336.
(e) Miners constructing or repairing
seals, certified persons under paragraph
(b) of this section, and senior mine
management officials under paragraph
(c) of this section shall be trained prior
to constructing or repairing a seal. The
training shall address materials and
procedures in the approved seal design
and ventilation plan. The mine operator
must certify the date of training
provided each miner, certified person,
and senior mine management official
and retain each certification for one
year.
I
5. Add § 75.338 to read as follows:
§ 75.338
Seals records.
(a) The table entitled ‘‘Seal
Recordkeeping Requirements’’ lists the
records the operator must maintain
pursuant to §§ 75.335, 75.336, and
75.337, and the duration for which
particular records need to be retained.
TABLE TO § 75.338(a).—SEAL RECORDKEEPING REQUIREMENTS
Section
reference
(1) Protocol to monitor methane and oxygen and maintain an
inert atmosphere..
(2) Training of certified persons ................................................
(3) Gas sampling records ..........................................................
(4) Approved seal design ..........................................................
jlentini on PROD1PC65 with RULES2
Record
75.335(b) ..........
Same as ventilation plan requirements.
75.335(b)(2) ......
75.335(b)(6) ......
75.336(b)(1) ......
(5) Certification of provisions of approved seal design is addressed.
(6) Record of examinations .......................................................
(7) Seal construction certification ..............................................
75.336(b)(2) ......
1 year.
1 year.
As long as the seal is needed to serve the purpose for which
it is built.
As long as the seal is needed to serve the purpose for which
it is built.
1 year.
As long as the seal is needed to serve the purpose for which
it is built.
VerDate Aug<31>2005
21:07 May 21, 2007
Jkt 211001
PO 00000
Frm 00022
75.337(b)(5) ......
75.337(c) ..........
Fmt 4701
Sfmt 4700
Retention time
E:\FR\FM\22MYR2.SGM
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Federal Register / Vol. 72, No. 98 / Tuesday, May 22, 2007 / Rules and Regulations
28817
TABLE TO § 75.338(a).—SEAL RECORDKEEPING REQUIREMENTS—Continued
Record
Section
reference
(8) Certification of training .........................................................
75.337(e) ..........
jlentini on PROD1PC65 with RULES2
(b) Records required by §§ 75.335,
75.336, and 75.337 shall be retained at
a surface location at the mine in a
secure book that is not susceptible to
alteration. The records may be retained
electronically in a computer system that
is secure and not susceptible to
alterations, if the mine operator can
immediately access the record from the
mine site.
(c) Upon request from an authorized
representative of the Secretary of Labor,
VerDate Aug<31>2005
21:07 May 21, 2007
Jkt 211001
Retention time
1 year.
the Secretary of Health and Human
Services, or from the authorized
representative of miners, mine operators
must promptly provide access to any
record listed in the table in this section.
(d) Whenever an operator ceases to do
business, that operator must transfer all
records required to be maintained by
this part, or a copy thereof, to any
successor operator who must maintain
them for the required period.
PO 00000
Frm 00023
Fmt 4701
Sfmt 4700
6. Amend § 75.371 by revising
paragraph (ff) to read as follows:
I
§ 75.371
Mine ventilation plan; contents.
*
*
*
*
*
(ff) The sampling protocol as provided
by § 75.335(b) and seal installation
requirements provided by § 75.336(b)(3).
*
*
*
*
*
[FR Doc. 07–2535 Filed 5–17–07; 3:11 pm]
BILLING CODE 4510–43–P
E:\FR\FM\22MYR2.SGM
22MYR2
Agencies
[Federal Register Volume 72, Number 98 (Tuesday, May 22, 2007)]
[Rules and Regulations]
[Pages 28796-28817]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 07-2535]
[[Page 28795]]
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Part III
Department of Labor
-----------------------------------------------------------------------
Mine Safety and Health Administration
-----------------------------------------------------------------------
30 CFR Part 75
Sealing of Abandoned Areas; Final Rule
Federal Register / Vol. 72, No. 98 / Tuesday, May 22, 2007 / Rules
and Regulations
[[Page 28796]]
-----------------------------------------------------------------------
DEPARTMENT OF LABOR
Mine Safety and Health Administration
30 CFR Part 75
RIN 1219-AB52
Sealing of Abandoned Areas
AGENCY: Mine Safety and Health Administration (MSHA), Labor.
ACTION: Emergency temporary standard; Notice of public hearings; Notice
of close of comment period.
-----------------------------------------------------------------------
SUMMARY: The Mine Safety and Health Administration (MSHA) is issuing an
emergency temporary standard (ETS) under section 101(b) of the Federal
Mine Safety and Health Act of 1977 in response to the grave danger that
miners face when underground seals separating abandoned areas from
active workings fail. MSHA has concluded from its investigations of
mine explosions that occurred and other recent reports, that additional
immediate action is necessary to protect miners. This ETS includes
requirements to strengthen the design, the construction, the
maintenance, and the repair of seals, as well as requirements for
sampling and controlling atmospheres behind seals. It also increases
the level of overpressure for new seals, thus implementing the
requirements of the Mine Improvement and New Emergency Response (MINER)
Act of 2006.
DATES: This emergency temporary standard is effective May 22, 2007.
This standard must be replaced with a final rule within 9 months. MSHA
will hold public hearings on July 10, 2007, July 12, 2007, July 17,
2007 and July 19, 2007 at the locations listed in the Public Hearings
section below under the SUPPLEMENTARY INFORMATION section of this
document. If individuals or organizations wish to make an oral
presentation for the record, the Mine Safety and Health Administration
(MSHA) is asking that you submit your request at least 5 days prior to
the hearing dates. The comment period will close on July 6, 2007.
ADDRESSES: Comments must be clearly identified and may be submitted by
any of the following methods:
(1) Federal Rulemaking Portal: https://www.regulations.gov. Follow
the instructions for submitting comments.
(2) Electronic mail: zzMSHA-Comments@dol.gov. Include ``RIN 1219-
AB52'' in the subject line of the message.
(3) Telefax: (202) 693-9441. Include ``RIN 1219-AB52'' in the
subject.
(4) Regular Mail: MSHA, Office of Standards, Regulations, and
Variances, 1100 Wilson Blvd., Room 2350, Arlington, Virginia 22209-
3939.
(5) Hand Delivery or Courier: MSHA, Office of Standards,
Regulations, and Variances, 1100 Wilson Blvd., Room 2350, Arlington,
Virginia 22209-3939. Sign in at the receptionist's desk on the 21st
floor.
Docket: Comments can be accessed electronically at www.msha.gov
under the ``Rules and Regs'' link. MSHA will post all comments on the
Internet without change, including any personal information provided.
Comments may also be reviewed at the Office of Standards, Regulations,
and Variances, 1100 Wilson Blvd., Room 2350, Arlington, Virginia.
MSHA maintains a listserve that enables subscribers to receive e-
mail notification when rulemaking documents are published in the
Federal Register. To subscribe to the listserve, go to https://
www.msha.gov/subscriptions/subscribe.aspx.
Information Collection Requirements: Comments concerning the
information collection requirements must be clearly identified as such
and sent to both the Office of Management and Budget (OMB) and MSHA as
follows:
(1) OMB: All comments must be sent by mail addressed to the Office
of Information and Regulatory Affairs, Office of Management and Budget,
New Executive Office Building, 725 17th Street, NW., Washington, DC
20503, Attn: Desk Officer for MSHA; and
(2) MSHA: Comments must be clearly identified by RIN 1219-AB46 as
comments on the information collection requirements and transmitted
either electronically to zzMSHA-Comments@dol.gov, by facsimile to (202)
693-9441, or by regular mail, hand delivery, or courier to MSHA, Office
of Standards, Regulations, and Variances, 1100 Wilson Blvd., Room 2350,
Arlington, Virginia 22209-3939.
Hearings: Locations of the public hearings are in the SUPPLEMENTARY
INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Patricia W. Silvey, Director, Office
of Standards, Regulations, and Variances, MSHA, 1100 Wilson Blvd, Room
2350, Arlington, Virginia 22209-3939, silvey.patricia@dol.gov (e-mail),
(202) 693-9440 (voice), or (202) 693-9441. (telefax).
SUPPLEMENTARY INFORMATION: The outline of this ETS is as follows:
I. Public Hearings
II. Introduction
III. Basis for the Emergency Temporary Standard
A. Regulatory Authority
B. Grave Danger
IV. Discussion of the Emergency Temporary Standard
A. Background
B. General Discussion
C. Section-by-Section Analysis
V. Executive Order 12866
A. Population-at-Risk
B. Benefits
C. Compliance Costs
VI. Feasibility
A. Technological Feasibility
B. Economic Feasibility
VII. Regulatory Flexibility Act and Small Business Regulatory
Enforcement Fairness Act (SBREFA)
A. Definition of a Small Mine
B. Factual Basis for Certification
VIII. Paperwork Reduction Act of 1995
A. Summary
B. Details
IX. Other Regulatory Considerations
X. References
XI. Emergency Temporary Standard--Regulatory text
I. Public Hearings
MSHA will hold four public hearings on the ETS. The public hearings
will begin at 9 a.m. and end after the last speaker speaks, and in any
event not later than 5 p.m., on the following dates at the locations
indicated:
------------------------------------------------------------------------
Date Location Phone
------------------------------------------------------------------------
July 10, 2007................. Lakeview Golf Resort 800-624-8300
and Spa, One Lakeview
Drive, Morgantown, WV
26508.
July 12, 2007................. Crowne Plaza Hotel, 859-255-4281
1375 South Broadway,
Lexington, KY 40504.
July 17, 2007................. Embassy Suites Denver, 303-696-6644
7525 East Hampden
Avenue, Denver, CO
80231.
July 19, 2007................. Sheraton Birmingham 205-324-5000
Hotel, 2101 Richard
Arrington Jr.
Boulevard North,
Birmingham, AL 35203.
------------------------------------------------------------------------
The hearings will begin with an opening statement from MSHA,
followed by an opportunity for members of the public to make oral
presentations. You do not have to make a written request to speak.
Speakers will speak in the order that they sign in. Any unallotted time
will be made available for persons making same-day requests.
[[Page 28797]]
At the discretion of the presiding official, the time allocated to
speakers for their presentation may be limited. Speakers and other
attendees may also present information to the MSHA panel for inclusion
in the rulemaking record. The hearings will be conducted in an informal
manner. The hearing panel may ask questions of speakers. Although
formal rules of evidence or cross examination will not apply, the
presiding official may exercise discretion to ensure the orderly
progress of the hearing and may exclude irrelevant or unduly
repetitious material and questions. A verbatim transcript of the
proceedings will be prepared and made a part of the rulemaking record.
Copies of the transcript will be available to the public. The
transcript will also be available on MSHA's Home Page at https://
www.msha.gov, under Statutory and Regulatory Information.
MSHA will accept post-hearing written comments and other
appropriate data for the record from any interested party, including
those not presenting oral statements. Written comments will be included
in the rulemaking record.
II. Introduction
This ETS is issued under section 101(b) of the Federal Mine Safety
and Health Act of 1977 (Mine Act) as amended by the Mine Improvement
and New Emergency Response Act of 2006 (MINER Act), 30 U.S.C. 811(b).
The ETS establishes or revises standards in part 75--subpart D--
Ventilation. These new standards strengthen the design, construction,
maintenance, and repair of seals and monitoring and control of
atmospheres behind seals in order to reduce the risk of seal failure
and the risk of explosions in abandoned areas of underground coal
mines.
In accordance with section 101(b)(3) of the Mine Act, an Emergency
Temporary Standard (ETS) serves as both a final rule with immediate
effect and a proposed rule to establish a final rule through the notice
and comment process. Therefore, the final rule may differ from an ETS
just as any final rule may differ from a proposed rule. The Mine Act
states that the ETS is a temporary standard and must be superseded by a
final rule within nine months. The Legislative History of the Mine Act
reinforces the statutory language regarding the ETS serving as a
proposed rule ``so that all views can be carefully considered in
connection with the issuance of a permanent standard.'' S. Rept. 181,
95th Cong., 1st Sess. 24 (1977).
The preamble discusses specific provisions that may be included in
the final rule and MSHA solicits comments on these provisions.
III. Basis for the Emergency Temporary Standard
A. Regulatory Authority
Section 101(b) of the Mine Act provides that:
1. The Secretary shall provide, without regard to the requirements
of chapter 5, title 5, United States Code, for an emergency temporary
mandatory health or safety standard to take immediate effect upon
publication in the Federal Register if [s]he determines (A) that miners
are exposed to grave danger from exposure to substances or agents
determined to be toxic or physically harmful, or to other hazards, and
(B) that such emergency standard is necessary to protect miners from
such danger.
2. A temporary mandatory health or safety standard shall be
effective until superseded by a mandatory standard promulgated in
accordance with the procedures prescribed in paragraph (3) of this
subsection.
3. Upon publication of such standard in the Federal Register, the
Secretary shall commence a proceeding in accord with section 101(a)
[involving notice and comment], and the standards as published shall
also serve as a proposed rule for the proceeding. The Secretary shall
promulgate a mandatory health or safety standard under this paragraph
no later than nine months after publication of the emergency temporary
standard as provided in paragraph (2).
An ETS is an extraordinary measure provided by the Mine Act to
enable MSHA ``to react quickly to grave dangers that threaten miners
before those dangers manifest themselves in serious or fatal injuries
or illnesses.'' S. Rept. 181, 95th Cong., 1st Sess. 23 (1977).
Additionally, ``* * * once the Secretary has identified a grave danger
that threatens miners the Committee expects the Secretary to issue an
emergency temporary standard as quickly as possible, not necessarily
waiting until [she] can investigate how well that grave danger is being
managed or controlled in particular mines.'' Senate Report at 24. An
ETS takes effect upon publication in the Federal Register, and is a
fully enforceable standard.
To assure the comprehensive protection of miners, the ETS authority
applies to all types of grave dangers without qualification. The
legislative history of the Mine Act emphasizes that ``to exclude any
kind of grave danger would contradict the basic purpose of emergency
temporary standards protecting miners from grave dangers.'' S. Rept.
181, 95th Cong., 1st Sess., 24 (1977). The ETS authority thus covers
dangers arising from exposure to toxic or physically harmful substances
or agents and to ``other hazards.'' It applies to dangers longstanding
or novel, to dangers that ``result from conditions whose harmful
potential has just been discovered'' or to which large numbers of
miners are ``newly exposed.'' Id.
A record of fatalities or serious injuries is not necessary before
an ETS can be issued because ``[d]isasters, fatalities, and
disabilities are the very thing this provision is designed to
prevent.'' Id. at 23. At the same time, the legislative history of the
Mine Act is clear that an ETS is not limited to new dangers in the
mining industry: ``That a danger has gone unremedied should not be a
bar to issuing an emergency standard. Indeed, if such is the case the
need for prompt action is that much more pressing.'' Id. at 24.
When issuing an ETS, MSHA is ``not required to prove the existence
of grave danger as a matter of record evidence prior to taking
action.'' Id. The legislative history expressly recognizes ``the need
to act quickly where, in the judgment of the Secretary, a grave danger
to miners exists.'' Id. The ETS is a critical statutory tool that MSHA
can use to take immediate action to prevent the loss of life in the
mines. MSHA accordingly has employed an ETS previously to order
``hands-on'' training for miners in the use of self-contained self-
rescue (SCSR) devices 52 FR 24373 (June 30, 1987), to order certain
training and mine evacuation procedures for underground coal mines 67
FR 76658 (December 12, 2002) and to order new accident notification
timeframes, provide new safety equipment, training and drills in mine
emergency evacuations 71 FR 12252, (March 9, 2006).
B. Grave Danger
Based on MSHA's accident investigation reports of the Sago and
Darby mine explosions,\1\ the National Institute for Occupational
Safety and Health's (NIOSH) reports on explosion testing and modeling,
MSHA's in-mine seal evaluations, and review of technical literature,
MSHA has determined that new comprehensive standards for seal design
approval, strength and installation approval, construction, maintenance
and repair, sampling and monitoring, training and recordkeeping
[[Page 28798]]
are necessary to immediately protect miners from hazards of sealed
areas.
---------------------------------------------------------------------------
\1\ MSHA Report of Investigation/Mine Explosion, Sago Mine,
January 2, 2006 and MSHA Report of Investigation/Mine Explosion,
Darby Mine Number 1, May 20, 2006. These reports can be found on
MSHA's Web site at: https://www.msha.gov.
---------------------------------------------------------------------------
Underground coal mines are dynamic work environments in which the
working conditions can change rapidly. Caved, mined-out areas may
contain coal dust and accumulated gas which can be ignited by rock
falls, lightning, and in some instances, fires started by spontaneous
combustion. Seals are used to isolate and contain this environment of
the active workings of the mine. Adequate seals are crucial to prevent
an explosion from propagating to the outby side of the seal where
miners work or travel. Seals must therefore be designed to withstand
elevated pressures and contain explosions by preventing potentially
explosive or toxic gasses from migrating into the active working areas
of underground coal mines. Miners rely on seals to protect them from
the hazardous and sometimes explosive environments within the sealed
area.
The existing safety standards for construction of solid-concrete
block seals adopt specific construction criteria. Existing requirements
addressing construction of seals using equivalent alternative materials
and methods were established, as an interim measure, in MSHA's Program
Information Bulletin No. P06-16, ``Use of Alternative Seal Methods and
Materials Pursuant to 30 CFR 75.335(a)(2)),'' issued on July 19, 2006
(July 2006 PIB). Under the July 2006 PIB, MSHA increased the strength
requirements for new alternative seals to reliably withstand an
overpressure of at least 50 pounds per square inch gauge (psig) in the
conditions in which they will be installed as demonstrated by well-
defined and certified engineering designs. An alternative seal design
could also be approved based on actual test results validating the
psig. All seal construction must be approved by the District Manager in
the mine's ventilation plan. To be considered for approval, mine
operators must have a professional engineer (PE) who is knowledgeable
in structural engineering to certify seal designs and supporting data.
In addition, the proposed ventilation plan must provide that a senior
mine management official (such as mine manager, superintendent, etc.)
certify that the construction, installation, and materials used were in
accordance with the mine's approved ventilation plan. Furthermore, the
July 2006 PIB requires an assessment of the atmosphere behind existing
alternative seals to determine the potential for an explosion and to
assess seal integrity. The July 2006 PIB requires the operator to take
remedial actions which may include inerting the sealed atmosphere,
increasing the capacity of the existing seal to withstand at least 50
psig overpressure, constructing an additional alternative seal having
this capacity, or constructing a solid-concrete seal. Finally, the July
2006 PIB requires that high risk seals, (such as if failure could
adversely affect miners' safety) and seals with a poor performance
history will require additional actions to better protect miners,
including periodic monitoring of the atmosphere behind the seals.
MSHA determined in the Sago accident that even though the seals
were not constructed as approved in the ventilation plan, they still
could withstand an explosion overpressure of 21 psi. In the Agency's
root cause analysis of the Sago accident, MSHA found that: (1) The
seals were not capable of withstanding the forces generated by the
explosion; (2) The atmosphere in the sealed area was not monitored and
it contained explosive methane/air mixtures; (3) Lightning was the most
likely ignition source for the explosion with the energy transferring
onto an abandoned pump cable in the sealed area and providing an
ignition source for the explosion. MSHA found that the explosive forces
generated behind the sealed area in the Sago accident were at least 93
psi.
In the Darby accident, MSHA found that the seals were improperly
constructed and had an inadequate pressure rating. MSHA also concluded
that the use of an oxygen acetylene cutting torch to cut a metal strap
outby a seal was the most likely ignition source. MSHA further
concluded that when seals are improperly constructed, they present a
hazard to miners, even when ignition sources are located outby the
seal.
When seals are improperly constructed and maintained, air may leak
excessively through the seals, which may result in explosive conditions
inby the seals. The air leakage causes increased levels of hazardous
conditions whereby introduction of ignition sources could cause an
explosion. Air leakage from the sealed area to active working areas
could also contaminate the atmospheres, resulting in miners being
exposed to potential explosions or toxic gasses.
In addition, the ETS requires that insulated cables and metallic
objects through or across seals be removed from the area to be sealed,
and prohibits welding, cutting or soldering with an arc or flame within
150 feet of a seal. The July 2006 PIB's interim action has serious
limitations in that it fails to provide comprehensive protection for
miners from the dangers of explosions in sealed areas: it only permits
testing as one method of demonstrating seal strength; it does not
address explosion forces generated behind a sealed area that are
greater than 50 psi; it requires only a one-time assessment of the
atmosphere behind the seal rather than a sampling plan approved by MSHA
as required under the ETS; although the July 2006 PIB states that
periodic monitoring of sealed areas may be required for high risk seals
(such as if failure could adversely affect miners' safety), a periodic
monitoring frequency was not specified in the July 2006 PIB; the July
2006 PIB does not address the hazard of welding, cutting, and soldering
with an arc or flame in close proximity to a seal. Therefore, hazards
in existing sealed areas present a grave danger to miners.
The Secretary has therefore determined that miners are exposed to
grave danger if existing and new seals are not properly constructed,
maintained, monitored, and repaired in accordance with this ETS.
In addition, for the above-stated reasons under the Administrative
Procedure Act (APA), 5 U.S.C. 553(b)(B) and (d)(3), MSHA finds good
cause exists to dispense with notice and comment and make the ETS
effective immediately. To delay the effective date of the ETS is
contrary to the public interest because any delay in the ETS effective
date further exposes miners to grave danger from inadequately designed,
constructed, maintained, and repaired seals.
IV. Discussion of the Emergency Temporary Standard
A. Background
In the Federal Coal Mine Health and Safety Act of 1969 (Coal Act),
the predecessor to the existing Mine Act, Congress first recognized
that mine operators must seal abandoned and isolated areas of
underground coal mines for the protection of miners' safety:
In the case of mines opened on or after the operative date of
this title, or in the case of areas developed on or after such date
in mines opened prior to such date, the mining system shall be
designed, in accordance with a plan and revisions thereof approved
by the Secretary and adopted by the operator, so that, as each set
of cross entries, room entries, or panel entries of the mine are
abandoned, they can be isolated from active workings of the mine
with explosion-proof bulkheads.
Pub. L. 91-173 (Dec. 1969) Section 303(2)(3)).
In the conference report filed in the House, the statement of the
managers on
[[Page 28799]]
the part of the House stated, regarding the requirement that an
abandoned area of a mine either be ventilated or sealed that:
[t]he determination of which method [(ventilated or sealed)] is
appropriate and the safest at any mine is up to the Secretary or
[her] inspector to make, after taking into consideration the
conditions of the mine, particularly its history of methane and
other explosive gases. The objective is that [s]he require the means
that will provide the greatest degree of safety in each case. * * *
When sealing is required, such sealing shall be made in an approved
manner so as to isolate with explosion-proof bulkheads such areas
from the active working of the mine.
Under the conference substitute, paragraph (3) of section 303(z)
provides that, in the case of mines opened on or after the operative
date of this title, or in the case of areas developed on or after
such date in mines opened prior to such date, the mining system
shall be designed, in accordance with a plan and revisions thereof
approved by the Secretary and adopted by the operator, so that, as
each set of cross entries, room entries, or panel entries of the
mine are abandoned, they can be isolated from active workings of the
mine with explosion-proof bulkheads approved by the Secretary or his
inspector.
The managers expect the Secretary to take the lead in improving
technology in this area of controlling methane accumulations in gob
areas and to improve upon this important section 303(z).
Conf. Rep. No. 91-761, 91Fst Cong. 1st Sess., 82 (Dec. 16, 1969)
(statement of the managers on part of the House) (emphasis added).
The Mine Act interim mandatory standards required seals to be
``made in an approved manner so as to isolate with explosion-proof
bulkheads such areas from the active workings of the mine.'' 30 U.S.C.
863(z)(2).
On May 15, 1992, as part of a comprehensive revision of its
regulations for ventilation of underground coal mines, MSHA published
standards for construction of seals in Sec. 75.335 of the ventilation
standards. The standard requires seals to be constructed of solid
concrete blocks at least six inches by eight inches by sixteen inches,
but allows seals to be constructed using alternative methods and
materials, provided, among other things, that the seal is capable of
withstanding a horizontal static pressure of 20 psi. MSHA based this
threshold on a U.S. Bureau of Mines 1971 report entitled ``Explosion-
Proof Bulkheads--Present Practices.''
A number of manufacturers developed materials, such as cementitious
foams and glass-fiber material, which were tested and subsequently
deemed suitable for use in alternative seals and marketed under various
trade names. MSHA required the manufacturers to have full-scale seals
be subjected to explosion testing at NIOSH's Lake Lynn Experimental
Mine (Lake Lynn). MSHA then intended for mine operators to construct
seals as constructed and tested at Lake Lynn.
On January 2, 2006, an explosion at the Sago Mine in Upshur County,
West Virginia caused the death of twelve miners. Later that year, on
May 20, 2006, an explosion at the Darby Mine No. 1 in Harlan County,
Kentucky, caused the death of five miners. Common to both of these
accidents was the failure of the seals in the mine. The failed seals in
both mines were constructed with the same approved alternative material
for a 20 psi seal. None of the failed seals were constructed in the
same manner as they were constructed at Lake Lynn. Therefore, MSHA
issued a moratorium on alternative methods and materials for
construction of new seals (Program Information Bulletin (PIB) No. P06-
11, June 1, 2006, reissued on June 12, 2006 as PIB No. P06-12.).
Following these underground coal mine disasters in 2006, Congress
passed and the President signed the MINER Act. Section 10 of the MINER
Act requires that the Secretary issue mandatory health and safety
standards for seals of abandoned areas no later than December 15, 2007.
It also requires the Secretary to revise the current standard to
increase the 20 psi standard for alternative seals.
Seal failures at the Sago Mine and Darby No. 1 Mine in 2006 raised
awareness of the problems with seal construction and the design
criterion of a 20-psi static horizontal pressure. MSHA continued its
investigation of these and other failures of alternative seals, and
conducted in-mine evaluations of existing alternative seals. It also
reviewed the history of seals in the United States and other countries.
Presently, most coal producing countries have coal mine seal
requirements that are in excess of a 20-psi overpressure. As a result
of MSHA's continued investigations and in-mine evaluations, MSHA
increased the strength of alternative seals to 50 psi and addressed a
number of other issues related to the construction and the
effectiveness of current alternative and solid concrete block seals in
Program Information Bulletin No. P06-16, ``Use of Alternative Seal
Methods and Materials Pursuant to 30 CFR 75.335(a)(2)),'' issued on
July 19, 2006 (July 2006 PIB).
On February 8, 2007, NIOSH issued a draft report, ``Explosion
Pressure Design Criteria for New Seals in U.S. Coal Mines'' (2007 NIOSH
Draft Report). The draft report states that ``mine seals and their
related systems such as the monitoring, inertization and ventilation
systems require the highest level of engineering and quality assurance.
Successful implementation of the seal design criteria and
recommendations in this report should reduce the risk of seal failure
due to explosions in abandoned areas of underground coal mines.'' (2007
NIOSH Draft Report at 40). In the executive summary of the draft
report, NIOSH makes recommendations for formulating seal design
criteria.
B. General Discussion
Existing Sec. 75.334(a) requires that inactive areas of
underground coal mines be ventilated or sealed. Most inactive areas are
sealed because of ground control, ventilation issues, and the long-term
costs of maintaining ventilation and roof support in inactive areas.
Seals are also installed to withstand overpressures resulting from
explosions in inactive areas and to prevent the potentially explosive
methane/air mixtures from migrating to the working areas.
A methane/air mixture becomes explosive when 5 percent to 15
percent methane is present with at least a 12 percent oxygen
concentration. If an ignition source is available, then an explosion
can occur and create high overpressures. The homogeneity of the
methane/air mixture contributes to its explosiveness. The homogeneity
of the methane/air mixture can vary depending on the elevation and the
methane liberation of the sealed area and outside factors such as the
current temperature and barometric pressure. The speed of an explosion
and the physical characteristics of a sealed area can increase the
force of the explosion such that detonations and significant pressure
piling are possible.
In order to address mine conditions that influence the magnitude of
overpressures in explosions, seals need to be designed and constructed
properly and then inspected on a periodic basis and properly maintained
to ensure their reliability. The 2007 NIOSH Draft Report states as
follows:
NIOSH engineers examined seal design criteria and practices used
in the U.S., Europe and Australia and then classified seals into
their various applications. Next, NIOSH engineers considered various
kinds of explosive atmospheres that can accumulate within sealed
areas and used simple gas explosion models to estimate worst case
explosion pressures that could impact seals. Three design pressure
pulses (pressure-time curves) were developed for the dynamic
structural analysis of new seals under the conditions in which those
seals may be used: unmonitored seals where there is a
[[Page 28800]]
possibility of methane-air detonation behind the seal; Unmonitored
seals with little likelihood of detonation; and monitored seals
where the amount of potentially explosive methane-air is strictly
limited and controlled. These design pressure pulses apply to new
seal design and construction.
For the first condition, an unmonitored seal with the
possibility of detonation, the recommended design pulse rises to 4.4
MPa (640 psi) and then falls to the 800 kPa (120 psi) constant
volume explosion overpressure. For unmonitored seals without the
possibility of detonation, a less severe design pulse that simply
rises to the 800 kPa (120 psi) constant volume explosion
overpressure, but without the initial spike, may be employed. For
monitored seals, engineers can use a 345 kPa (50 psi) design pulse
if monitoring can assure (1) that the maximum length of explosive
mix behind a seal does not exceed 5 m (15 ft) and (2) that the
volume of explosive mix does not exceed 40% of the total sealed
volume. Use of this 345 kPa (50 psi) design pulse requires
monitoring and active management of the sealed area atmosphere.
Based on MSHA's accident investigation reports of Sago and Darby
mine explosions, NIOSH reports on explosion testing and modeling,
MSHA's in-mine seal evaluations, and review of technical literature,
MSHA identified a number of issues pertinent to the construction and
efficacy of current alternative and solid concrete block seals.
C. Section-by-Section Analysis
1. Sec. 75.335 Seals Requirements
The ETS increases seal strength requirements for construction of
new seals and, where necessary, establishes new requirements for
monitoring and inerting atmospheres of sealed areas. New Sec.
75.335(a) provides that seals constructed in underground coal mines
after May 22, 2007 must be designed, constructed and maintained in
accordance with MSHA approval of a mine operator's design application
and installation procedures incorporated in the ventilation plan.
The ETS establishes a three-tiered approach for overpressure
loading criteria applicable to new seals: (1) 50 psi overpressure; (2)
120 psi overpressure; and (3) an overpressure greater than 120 psi. For
purposes of this ETS, MSHA intends that overpressure be any pressure
exerted by the forces of an explosion that is above normal atmospheric
pressure. In developing these overpressure loading criteria, MSHA
relied upon the 2007 NIOSH Draft Report, the Agency's safety and health
experience with respect to seals and underground mining conditions and
investigations, and accepted scientific and engineering principles.
Under the ETS, if a mine operator monitors and maintains the
atmosphere in these areas inert, new Sec. 75.335(a)(1) requires a seal
design to withstand at least 50 psi overpressure. If a mine operator
does not monitor and maintain atmospheres in these areas inert, new
Sec. 75.335(a)(2) requires a seal design to withstand at least 120 psi
overpressure. A seal design that will withstand an overpressure greater
than 120 psi is required under new Sec. 75.335(a)(3) when the mine
operator does not monitor and maintain the atmosphere within sealed
areas inert and when: (1) The atmosphere in the area is likely to
contain homogeneous mixtures of methane between 4.5 percent and 17.0
percent, and oxygen exceeding 17.0 percent throughout the entire sealed
area; (2) or pressure piling is likely due to opening restrictions near
the proposed seal area; or (3) other conditions are encountered, such
as the likelihood of a detonation in the proposed seal area. Where the
conditions in Sec. 75.335(a)(3) are likely to occur, the mine operator
must revise the ventilation plan required by existing Sec. 75.370 to
address the appropriate seal strength.
The ETS does not require mine operators to upgrade seals
constructed prior to May 22, 2007. However, new Sec. 75.335(b)
enhances the protection afforded miners under the previous standard by
requiring, among other things, that atmospheres in the sealed areas be
monitored and inerted. If a mine operator does not monitor and inert
the atmosphere in an existing sealed area, the strength of the seals
must be increased to 120 psi or greater.
a. Sec. 75.335(a)
New paragraph (a)(1) requires that seals be constructed to
withstand 50 psi overpressure. However, mine operators who construct
these seals must monitor the atmosphere behind the seals and maintain
them inert. Mine operators are currently required to construct seals
that will withstand 50 psi overpressure under the July 2006 PIB. In
addition, the July 2006 PIB required mine operators to assess
atmospheres behind alternative seals and take remedial action where
necessary. The 2007 NIOSH Draft Report also recommends a 50 psi
overpressure for monitored and managed atmospheres behind sealed areas.
Monitoring sealed areas allows the mine operator to know the
composition of potentially hazardous gases in sealed areas. Use of a 50
psi overpressure seal requires the mine operator to maintain an inert
atmosphere in the sealed area since explosions cannot occur within
inert atmospheres.
MSHA believes that in mines that liberate significant volumes of
methane, the atmosphere in sealed areas will become inert naturally. In
mines that produce very small volumes of methane, the atmosphere in
sealed areas may never approach explosive methane/air mixtures of 5
percent. However, some mines may need to actively inert the atmosphere
in the sealed area. To inert, an inert gas such as nitrogen or carbon
dioxide may be injected into the sealed area through boreholes or pipes
extending through the seals. The gas may be obtained from a bulk plant
and trucked to the mine site and pumped into the sealed area through a
borehole or pipe into the seal. It also may be produced at the mine
using a nitrogen generator, Tomlinson Boiler, or other inertization
device. This process is commonly used in underground coal mines in the
United States during firefighting activities and in other countries
where spontaneous combustion is common. MSHA is interested in receiving
comments regarding: (1) The economic and technological feasibility of
monitoring and inerting sealed atmospheres; and (2) methods of inerting
sealed atmospheres.
New paragraph (a)(2) requires 120 psi overpressure if the sealed
atmosphere is not monitored and maintained inert except as provided in
new paragraph (a)(3). This provision allows mine operators to install
seals that withstand 120 psi overpressure if they do not choose to
monitor and inert the sealed atmosphere. In MSHA's experience, the
overwhelming majority of underground coal mine explosions are typically
deflagrations. A deflagration occurs when the flame of an explosion
propagates through unburned fuel at a velocity below the speed of
sound. The faster the flame travels, the higher the pressures become.
Maximum pressures in a deflagration involving methane or coal dust are
limited to approximately 120 psi without the occurrence of detonation
or significant pressure piling. MSHA accident reports during the past
30 years do not reference an underground coal mine explosion in the
United States that generated an overpressure of greater than 120 psi
except in the rare instance when detonation occurred.
New paragraph (a)(3) also addresses overpressures resulting from
pressure piling and detonations. Methane is explosive between 5 percent
and 15 percent and requires at least 12 percent oxygen to ignite.
(NIOSH 2006, IC 9486) When ignited, an explosion can occur. To account
for correction factors of
[[Page 28801]]
methane detection equipment and potential contamination of the samples,
the ETS requires that methane concentrations between 4.5 percent and
17.0 percent shall be used to determine an explosive atmosphere. If
ignited, large volumes of homogeneous explosive methane/air mixtures in
a sealed area can generate high explosion overpressures. The
homogeneity of methane/air mixtures in a sealed area is affected by a
number of factors such as elevation, temperature, methane liberation,
and barometric pressure. Based on Agency experience, MSHA anticipates
that there will be few mines that have homogeneous explosive methane/
air mixtures throughout the entire area to be sealed. Commenters are
encouraged to submit information, with supporting documentation,
regarding the number of mines that may have homogeneous explosive
methane/air mixtures throughout the entire area to be sealed.
MSHA believes that detonations and significant pressure piling may
occur under certain situations. Detonations in underground coal mines
are rare. A detonation occurs when the flame of an explosion propagates
through the unburned fuel at a velocity exceeding the speed of sound
(1129 feet per second). Pressures resulting from a detonation involving
methane or coal dust can exceed 250 psi. Pressure piling occurs when
the atmosphere ahead of the flame front is compressed prior to the
arrival of the flame. When the flame burns through this compressed
mixture, an increase in the explosion pressure occurs. Thus, if this
mixture is compressed to 45 psi prior to the flame arriving, the
resulting explosion pressure could exceed 300 psi. Pressure piling can
occur when the physical configuration through which the explosion will
propagate inhibits the flow of gases for pressure equalization, such as
decreasing the number of entries, decreasing the size of the entries,
or obstructing the entry.
The ETS does not specify a seal strength under paragraph (a)(3).
Under this provision, the mine operator would submit a strength
requirement based on mine-specific conditions that are likely to result
in pressure piling or detonation in the sealed area. The mine operator
must first recommend the seal strength in the ventilation plan. MSHA
expects that mine operators will submit a thorough engineering analysis
conducted by a person knowledgeable in explosions and explosion
overpressures, based on the conditions in the mine. After the seal
strength is approved by the District Manager, the process in Sec.
73.336 will apply. MSHA expects that in these few instances, the
District Manager and the Office of Technical Support will coordinate
MSHA activities related to the approval process. MSHA believes that
most mine operators who encounter homogenous explosive methane/air
mixtures and pressure piling in the entire sealed area will monitor and
inert the atmosphere in sealed areas. Although the recommended maximum
seal strength in the 2007 NIOSH Draft Report is 640 psi, MSHA has no
empirical or other data, at this time, demonstrating that mine
conditions exist that will necessitate seals stronger than 120 psi.
MSHA requests comments from the mining community on the appropriateness
of the strategy in this ETS for addressing seal strength greater than
120 psi.
In the ETS, MSHA considered a performance-based approach to the
strength requirement for seals. However, MSHA included specific numbers
for the strength of seals in the ETS as the agency believes this
represents a more appropriate approach. MSHA specifically solicits
comments on the Agency's approach to the strength requirement for
seals.
MSHA is also interested in receiving comments on the
appropriateness of the three-tiered approach to seal strength in the
ETS. If commenters believe a different regulatory approach should be
developed for the final rule the Agency would like commenters to
provide: (1) The details for such a strategy, (2) rationale for such a
strategy; and (3) feasibility of using such strategy. The Agency
particularly seeks the views of the mining community regarding whether
there are other effective alternatives to the requirements in the ETS
with respect to providing the most appropriate and protective action
for miners exposed to hazards of existing sealed areas. Commenters
should provide supporting data, and specific alternatives, including
information on technological and cost implications.
Most existing seals were constructed to withstand a static
horizontal pressure of 20 psi. MSHA also considered requiring mine
operators to remove existing seals and replace them with seals that
withstand at least 50 psi. Currently, the Agency believes that
replacing existing seals is impractical, and in some instances, may
create safety hazards. In addition, these existing seals must be
monitored and the atmospheres behind them must be maintained inert. The
atmosphere inby and outby the seals near the roof, ribs, or floor
adjacent to the seal may contain low oxygen and/or explosive methane/
air mixtures that are highly hazardous to miners' safety. In addition,
the conditions inby the seals, such as bad roofs, roof falls, and water
accumulations, may prevent the mine operator from making changes to
provide adequate ventilation inby the seals. MSHA seeks comments on the
feasibility of including in the final rule a requirement that existing
seals be removed and replaced with a higher strength seal.
Another regulatory option that MSHA considered is whether to
require mine operators to build new seals outby existing seals. In some
cases, this may not be feasible because the seals may have been
constructed too close to the outby corner of the pillar so that there
is insufficient space to build new seals in the same pillar; and there
may not be an additional open entry outby the existing seals allowing
for construction of new seals.
MSHA also considered whether to require mine operators to reinforce
existing seals. The Agency is concerned with the feasibility of this
option and whether such a requirement could expose miners to greater
hazards as discussed earlier in this preamble. MSHA, however, will
continue to explore technological advances addressing feasible and safe
methods to reinforce existing seals in underground coal mines.
Commenters are encouraged to submit information and supporting data
regarding new technologies to reinforce seal strength.
Existing Sec. 75.335(a) included minimum specifications for seals
constructed of solid concrete blocks after November 15, 1992. Also,
existing Sec. 75.335 (a)(2) allowed mine operators to use alternative
construction methods or materials to construct a seal provided the seal
could withstand a static horizontal pressure of 20 psi (subsequently
increased to 50 psi in the July 2006 PIB). In addition, the method of
installation and material used had to be approved by the District
Manager under MSHA's ventilation plan procedures in Sec. 75.370 based
on a 1971 report entitled ``Explosion-Proof Bulkheads--Present
Practices,'' issued by the former U.S. Bureau of Mines. According to
that report, when a sealed atmosphere has adequate incombustible
material and minimum coal dust accumulations, it is doubtful that
pressures exceeding 20 psi could occur very far from the origin of the
explosion. The primary disadvantage of this level of explosion
protection is that current evidence establishes that explosions of coal
dust or methane can generate explosion pressures of 120 psi, without
detonation or pressure piling.
Previous Sec. 75.335(a)(2) also included measures to prevent
exposed timber
[[Page 28802]]
seals from quickly failing in a fire or other mine emergency. New
construction of timber seals must meet the requirements set forth in
this ETS.
b. Sec. 75.335(b) Sampling and Monitoring Requirements
ETS Sec. 75.335(b) establishes new sampling and monitoring
requirements for sealed areas. This provision requires that on the
effective date of this ETS, a certified person, as defined under
existing Sec. 75.100, must immediately monitor atmospheres in all
existing sealed areas when seals are outgassing, such as when the
barometric pressure in the sealed area exceeds the pressure on the
outby side of the sealed area. MSHA intends for mine operators to
establish a baseline analysis over a 14-day sampling period, as
specified under Sec. 75.335(b)(5)(iii), followed by weekly sampling
under paragraph (b)(1) of this section. While sampling is being
conducted, mine operators must train certified persons in sampling
procedures and develop a sampling protocol to be included in the
ventilation plan and submitted to the District Manager for approval.
This provision also requires that for seals constructed prior to
May 22, 2007 and seals designed for 50 psi overpressure according to
ETS Sec. 75.335(a)(1), mine operators shall develop and follow a
protocol to monitor methane and oxygen concentrations and to maintain
an inert atmosphere in sealed areas. The protocol shall be approved in
the ventilation plan. The sampling protocol must ensure that an inert
atmosphere behind the seal area is maintained. An explosion will not
occur in an inert atmosphere. The July 2006 PIB and this ETS require
mine operators to conduct an atmospheric assessment behind existing
alternative seals to determine the potential for an explosion and
assess seal integrity. This ETS requirement enhances protection of
miners working in the active portions of the mine adjacent to sealed
areas where existing seals were installed prior to this ETS. In
addition, this provision protects the miner where 50 psi seals will be
installed under this rule. MSHA recognizes that conditions in mines may
vary and mine operators can more appropriately address their specific
conditions in the ventilation plan. During 2006, MSHA inspected
existing seals. The inspections revealed that some mine operators were
not adhering to their approved ventilation plan for seal installation
and construction. The ETS emphasizes the importance of sampling sealed
atmospheres to ensure that they remain inert.
ETS Sec. 75.335(b)(1) requires that a trained certified person
sample atmospheres of sealed areas weekly when the barometric pressure
is decreasing or the seal is outgassing. Because the information
obtained during sampling of a sealed area is critical to the safety of
miners, the ETS requires sampling to be conducted by a certified
person. At least one sample shall be taken at each set of seals. If a
seal is ingassing, such as when the barometric pressure outside the
sealed area exceeds the pressure on the inby side of the sealed area
during the weekly examinations, the ETS requires that a sample shall be
collected during the next weekly examination to determine if the seal
will outgas. If the seal is ingassing during the second consecutive
weekly examination, the operator shall examine that seal daily until
the seal is outgassing, unless the seal does not outgas. In this
circumstance, an alternative protocol must be developed to effectively
evaluate the atmosphere in the sealed area and submitted to the
District Manager for approval. Although the ETS does not specify the
length of time that the seal must be examined to determine if it will
outgas, MSHA intends to require mine operators to develop the
alternative protocol within a reasonable timeframe. The District
Manager may approve different sampling frequencies and locations in the
ventilation plan or approve the use of atmospheric monitoring systems
in lieu of weekly sampling. The mine operator shall revise the protocol
in the ventilation plan if repeated sampling indicates that a seal is
not likely to outgas.
MSHA expects that the certified person will conduct sampling
required under the ETS as part of the examinations of seals required in
existing Sec. 75.360 and Sec. 75.364 and base the time of these
examinations on the barometric conditions to the extent possible. All
seals and the strata around them will leak air, resulting in an air
exchange near the seal during barometric changes. MSHA does not expect
the air leakage to significantly impact the atmosphere in a large
portion of the sealed area, but it may affect the atmosphere at a
sampling location when the seal is ingassing. Therefore, it is
important that samples be representative of the atmospheric conditions
in the larger portion of the sealed area, rather than just the area
immediately inby the seal.
The certified person must take at least one sample at each set of
seals during the weekly examination. Each newly constructed seal must
be equipped with two sampling pipes. In accordance with the ETS, MSHA
expects that most mines will need to take only one sample from a seal
in each set of seals. However, the number of seals that need to be
sampled will be determined from the results of the 14-day sampling
period specified in paragraph (b)(5)(iii) of this section.
If the seal is ingassing during the examination, the certified
person must attempt to take a sample during the next weekly
examination. After a second attempt is made and the seal is still
ingassing, attempts must be made daily until the seal outgasses. If
repeated sampling indicates that a seal is not likely to outgas, then
the mine operator must submit an alternative protocol to the District
Manager. The alternative protocol must address a means to effectively
evaluate the atmosphere in the sealed area. The alternate protocol may
address various means such as: (1) The use of a borehole or previously
installed sampling line to obtain samples, (2) pressure balancing of
the ventilation system to make the seals outgas, or (3) the use of
inert gas injection.
The District Manager may approve different sampling frequencies and
locations in the ventilation plan. This is intended to address those
instances when the atmosphere in the sealed area is unstable, close to
the explosive range, or subject to other hazardous conditions, such as
a history of spontaneous combustion, which make it necessary to sample
at a greater frequency. However, a less frequent sampling strategy may
be approved in the ventilation plan if the atmosphere in the sealed
area is stable and not at all close to explosive range. For example,
the oxygen must be significantly below 10 percent, and methane far less
than 3 percent or far greater than 20 percent.
Sampling requirements also addresses instances when an adequate
evaluation of the atmosphere in the sealed area cannot be obtained with
the sampling pipes located 15 feet inby the seal and into the center of
the first connecting crosscut inby the seal. In some sealed areas, the
District Manager may find it necessary to require in the ventilation
plan that samples be obtained at additional locations to determine that
the atmosphere is inert. Additional samples may need to be taken at
mines with sealed areas that are very large, have multiple sets of
seals, connect with another mine, have flooded areas, have capped
shafts, or in other circumstances which may cause samples of the
atmosphere taken near the seals not to be representative of the entire
sealed area.
The ETS also allows the use of an Atmospheric Monitoring System
(AMS)
[[Page 28803]]
in lieu of a person physically taking samples on a weekly basis. The
use of AMS is discussed more fully under paragraph (b)(5)(vi) of this
section.
MSHA believes that the sampling strategy in this ETS will yield
results that reflect a reasonable representation of the atmosphere in a
sealed area. MSHA is requesting comments addressing the sampling
approach in this ETS. The agency is particularly interested in comments
concerning sampling, and the sampling frequency, including sampling
only when a seal is outgassing. The Agency requests comments on whether
another sampling approach is more appropriate for a final rule, such as
when the seal is ingassing. MSHA also requests comments, information,
and experiences of the mining community concerning sampling sealed
areas.
Paragraph (b)(2) requires that certified persons shall be trained
in sampling procedures included in the protocol at paragraph (b)(5) of
this section prior to conducting sampling. This requirement would
ensure that certified persons conducting the sampling have the training
necessary to use the sampling devices and knowledge of the sampling
protocol requirements in the mine's ventilation plan.
This training shall be conducted by persons with knowledge of the
requirements in paragraph (b)(5) of this section. Training may be
conducted by a variety of people, including a manufacturer's
representative, ventilation engineer or a certified person at the mine.
MSHA expects the operator to utilize appropriate people to conduct the
training.
At a minimum, this training should include:
1. Relevant information in the mine's ventilation plan;
2. Sampling procedures including equipment and methods to be used;
3. Location of sampling points and sampling pipes;
4. The baseline analysis of oxygen and methane concentrations in a
sealed area over a 14-sampling day period;
5. Frequency of sampling for each set of seals;
6. Recording procedures required in paragraph (b)(6) of this
section;
7. Sampling frequency in the mine's ventilation plan, if an AMS is
used; and
8. General information concerning mine gases present in sealed
areas.
Training should include specific actions to take in implementing
the operator's ``action plan'' when methane concentrations are at one
of three different ranges and oxygen concentrations are 10.0 percent or
greater.
MSHA recognizes that the amount of time required to train a
certified person will vary. For this reason, MSHA is not specifying a
minimum amount of time for training, but instead a requirement that is
performance-oriented. MSHA anticipates that mine operators will adjust
the time required for this training based on the complexity of sampling
procedures, sampling protocol, and existing knowledge and skill level
of the certified person. MSHA also expects operators will include
``hands-on'' training during this session to assure that the certified
person demonstrates the necessary skills and abilities to perform the
tasks. Hands-on training would mean that a certified person
demonstrates to the trainer the necessary skills and abilities to
perform the testing for oxygen and methane. Hands-on training includes
practical application of the type of sampling equipment and the methods
to be used at the mine. Examples of this type of training include
calibration of sampling equipment, setup of equipment, and recognition
of the proper functioning of equipment.
All certified persons shall receive refresher training annually to
ensure that they maintain the competence necessary to effectively
perform the requirements in paragraph (b)(5) of this section. Annual
retraining shall be required within 12 months of the person receiving
initial or annual training. For example, a certified person receiving
initial training in May 2007 is expected to complete annual retraining
no later than the end of May 2008. The month that the refresher
training is completed establishes the anniversary month for the next
annual retraining. This is consistent with other MSHA training
requirements.
This ETS also requires mine operators to certify the date and
content of the training provided to the certified person. Operators are
required to retain these certifications for one year from the time
training was conducted. This provision is similar to other
certification requirements in part 75 in which the operator certifies
by signature and date that training was provided.
ETS Sec. 75.335(b)(3) states that the atmosphere in the sealed
area is considered inert when any of the following conditions occur:
(1) The oxygen concentration is less than 10.0 percent;
(2) The methane concentration is less than 3.0 percent; or
(3) The methane concentration is greater than 20.0 percent.
This ETS provision is consistent with MSHA guidance published in
the July 2006 PIB. The explosive range of methane is 5 to 15 percent
when the oxygen level is 12 percent or more (IC 9486, 2007 NIOSH Draft
Report). To allow for the inaccuracy of methane and oxygen detection
equipment and potential contamination of the samples, oxygen less than
10.0 percent, methane concentration less than 3.0 percent and methane
concentration greater than 20.0 percent were used to determine an inert
atmosphere.
ETS Sec. 75.335(b)(4) requires that when oxygen concentrations are
10.0 percent or greater and methane concentrations are from 3.0 percent
to 20.0 percent in a sealed area, the mine operator shall take two
additional gas samples at one hour intervals. If the two additional gas
samples are from 3.0 percent to 20.0 percent methane and oxygen is 10.0
percent or greater, then the mine operator shall initiate actions
required in ETS Sec. 75.335(b)(4)(i) or (ii). The ranges for methane
and oxygen in this paragraph include a margin of safety, account for
errors in instrumentation or sampling methods (NIOSH IC 9486), and
allow the mine operator to obtain confirming samples before
implementing the actions outlined in (b)(4)(i) and (b)(4)(ii). However,
because the atmosphere in the sealed area is critical to the safety of
miners, the ETS requires that samples be taken at one-hour intervals
under Sec. 75.335(b)(4).
Paragraphs (b)(4)(i) and (b)(4)(ii) of the ETS require the mine
operator to implement the action plan specified in the protocol or to
withdraw all persons from the affected area when the specified
concentrations are encountered. Historically, when methane levels
reached 4.5 percent in active areas of mines, miners were withdrawn
from the areas that were dangerous due to high concentrations of
methane. However, withdrawal of miners is not required if, under
paragraph (b)(4)(i), the operator chooses to implement the action plan
to address the actions to be taken by mine operators when the specified
concentrations in Sec. 75.335(b)(4) are reached; these concentrations
provide a margin of safety. However, the action plan must be approved
in the mine's ventilation plan and must provide protection to miners
equivalent to withdrawal under paragraph (b)(4)(ii). MSHA requests
comments on this approach and whether it provides adequate protection
for miners. Commenters are encouraged to submit specific language, with
supporting data for MSHA to consider for development of a final rule.
ETS Sec. 75.335(b)(5) establishes the elements that must be
addressed in a mine operator's sampling protocol and
[[Page 28804]]
actions to be taken when sampling results indicate that the atmosphere
behind the sealed area is not inert. Paragraph (b)(5)(i) requires that
the mine operator specify sampling procedures, including the type of
equipment and methods to be used by the mine operator for the sampling
program. MSHA believes most mine operators will use hand-held methane
and oxygen detection equipment that they currently have at the mine
site. Other operators may need to purchase detectors capable of
measuring high levels of methane. Although the mine operator may
collect samples in containers to be analyzed by a gas chromatograph,
the operator must specify in the protocol when the sample will be
analyzed and the procedures that will be followed when the sample
results indicate action levels are reached. The methods to be used
should include the physical connections to the sample pipes as well as
the length of time the detector or pump should be operated to collect
the sample. The length of time will be dependent on the length of the
sampling pipes.
ETS Sec. 75.335(b)(5)(ii) requires that the mine operator specify
in the sampling protocol the location of sampling points used for the
sealed area in a set of seals. The sampling points should be identified
on a mine map, or the operator should have a narrative description of
the location of the sampling points that can be readily identified on a
mine map.
ETS Sec. 75.335(b)(5)(iii) requires that the mine operator specify
procedures in the protocol to establish a baseline analysis of oxygen
and methane concentrations at each sampling point over a 14-day
sampling period. For existing seals, the mine operator must begin this
sampling upon the effective date of this rule. For newly constructed
seals, the mine operator must begin this sampling upon completion of
the seal construction.
The baseline shall be established after the atmosphere in the
sealed area is inert or the trend reaches equilibrium. These samples
would be taken by approved hand-held gas detectors or equipment that
collects samples in containers to be analyzed by gas chromatograph.
These samples need to be collected over a consecutive 14-day sampling
cycle to establish a baseline for a future sampling cycle at each
sampling point. Samples need only be taken when the seals are
outgassing during the baseline period to ensure samples are
representative of the larger area inby the seals. If the seals are not
outgassing during any of the days of sampling, the baseline sampling
period needs to be extended until 14 samples are taken. Once a baseline
is established, the seals need to be sampled at least weekly. MSHA is
requesting comments on this sampling approach. The agency is
particularly interested in comments concerning the establishment of a
baseline, including sampling only when a seal is outgassing and whether
it is appropriate to sample the atmosphere in sealed areas during
ingassing. MSHA also requests comments, information, and experiences
with sampling sealed areas, including data, analytical information,
establishment of equilibrium, and trends.
ETS Sec. 75.335(b)(5)(iv) establishes the frequency of sampling at
each seal or set of seals. Once a baseline is established, the seals
must be sampled at