Low- and Medium-Voltage Diesel-Powered Electrical Generators, 77728-77739 [05-24625]
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Federal Register / Vol. 70, No. 250 / Friday, December 30, 2005 / Rules and Regulations
and hazard training for miners as
follows:
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(o) Each operator engaged in shaft or
slope construction shall have an MSHAapproved training plan, as outlined in
this section, containing programs for
training new miners, training
experienced miners, training miners for
new tasks, annual refresher training,
and hazard training for miners as
follows:
(1) In the case of an operator engaged
in shaft or slope construction on
December 30, 2005, the operator shall
submit a plan for approval by May 1,
2006, unless extended by MSHA.
(2) In the case of a new shaft or slope
construction operator after June 28,
2006, the operator shall have an
approved plan prior to commencing
shaft or slope construction.
I 7. Paragraph (d) of § 48.28 is revised
to read as follows:
§ 48.8 Annual refresher training of miners;
minimum courses of instruction; hours of
instruction.
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*
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*
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(d) All persons employed as shaft or
slope construction workers on June 28,
2006 must receive annual refresher
training within 12 months of June 2006.
*
*
*
*
*
[FR Doc. 05–24624 Filed 12–29–05; 8:45 am]
BILLING CODE 4510–43–P
DEPARTMENT OF LABOR
Mine Safety and Health Administration
30 CFR Part 75
RIN 1219–AA98
Low- and Medium-Voltage DieselPowered Electrical Generators
Mine Safety and Health
Administration (MSHA), Labor.
ACTION: Final rule.
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AGENCY:
SUMMARY: This final rule amends an
existing safety standard to allow the use
of low- and medium-voltage dieselpowered electrical generators as an
alternative means of powering electrical
equipment in underground coal mines.
The final rule eliminates the need for
mine operators to file petitions for
modification to use these portable
generators to power electrical
equipment and does not reduce the
protections afforded miners by the
existing standards, in fact it increases
protections.
EFFECTIVE DATE: February 28, 2006.
FOR FURTHER INFORMATION CONTACT:
Rebecca J. Smith, Acting Director, Office
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of Standards, Regulations and
Variances, MSHA, 1100 Wilson
Boulevard, Arlington, Virginia 22209–
3939. Ms. Smith can be reached at
smith.rebecca@dol.gov (Internet e-mail)
(202–693–9443) (voice) or (202–693–
9441) (facsimile). The final rule also is
available on the Internet at https://
www.msha.gov/REGSINFO.HTM.
SUPPLEMENTARY INFORMATION:
I. Background Information
We (MSHA) are amending § 75.901 to
permit the use of low- and mediumvoltage diesel-powered electrical
generators as a means for providing a
portable source of power to move
equipment in, out, and around the mine
and to perform work in areas where
permissible equipment is not required.
This final rule does not reduce the
protections for miners in the current
standards, but increases miner safety by
updating the electrical requirements
with new commercially-available
technology so miners may use dieselpowered electrical generators as a
source of power. The final rule provides
protective systems and testing
procedures to limit the amount of
voltage and current that miners can be
exposed to under ground fault
conditions; thus, it reduces the
possibility of a fire, shock, or burn
hazard when miners use these
generators.
Furthermore, by issuing this final
rule, we are responding to the
requirements of the Regulatory
Flexibility Act and Executive Order
12866 that agencies review their
regulations to determine their
effectiveness and to implement any
changes indicated by the review that
will make the regulation more flexible
and efficient for stakeholders and small
businesses. In accordance with the
requirements of the Mine Act,
§ 101(a)(9), this final rule does not
reduce the protection afforded to miners
by the existing standard.
Generally, power centers are the main
means of supplying electricity in an
underground mine. Power centers are
placed underground to provide power to
permanent or stationary electrical
equipment, such as belt conveyor
drives, and to mining equipment on
working sections. Power centers in areas
where permissible equipment is not
required are generally stationary. Mine
operators use various means to move
electrical equipment and to perform
work in areas where permissible
equipment is not required. In these
situations, they are unable to use power
centers to energize the machines for the
move because of the excessive length of
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cable required to reach the power
center. If longer trailing cables are
installed in order to reach remote power
centers, proper electrical protection for
these low- and medium-voltage threephase circuits may be compromised and
overheating of, or damage to the cables
may occur.
Over a 13-year period (1990–2003),
through our petition for modification
(PFM) process, mine operators have
been using low- and medium-voltage
diesel-powered electrical generators as
an efficient means for providing a
portable source of power to move and
operate electrical equipment in areas
where permissible equipment is not
required. These portable diesel-powered
electrical generators are easily taken to
areas where power centers or other
sources of electrical power are not
available to move mobile equipment or
supply power to other electric
equipment needed to do work in outby
areas. Proper electrical protection for
these low- and medium-voltage threephase circuits can safely be provided by
portable diesel-powered electrical
generators.
Existing mandatory safety standards
§ 75.701 (Grounding metallic frames,
casings, and other enclosures of electric
equipment) and § 75.901 (Protection of
low- and medium-voltage three-phase
circuits used underground), specify the
grounding requirements for electrical
equipment and low- and mediumvoltage three-phase circuits. However,
when using these generators, mine
operators are unable to comply with the
existing electrical protection
requirements of § 75.901. Currently,
§ 75.901 requires a grounding circuit to
originate from the grounded side of a
grounding resistor located at a power
center. In addition, § 75.901 does not
address the use of a generator frame for
the purpose of grounding.
To address their inability to comply
with § 75.901, mine operators file PFMs
under section 101(c) of the Federal Mine
Safety and Health Act of 1977 (Mine
Act). PFMs may be granted when the
Secretary determines that an alternative
method of achieving the result of a
standard exists that will at all times
guarantee the same measure of
protection afforded to miners under a
standard, or when the application of a
standard to the mine will result in a
diminution of safety to the miners at the
mine. The PFM process results in safety
requirements and procedures that are
applicable only to an individual mine.
Once a final written decision pertaining
to a PFM has been issued, the governing
terms and conditions contained in the
decision become the mandatory
standard at the individual mine. After
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the PFM is issued, we continue to
monitor compliance with its terms and
conditions.
During the time period January 1990
through October 2003, we granted 63
PFMs that requested the use of dieselpowered electrical generators. These
PFMs affected 56 mines.
The first petition granted for a
modification of § 75.901 was submitted
to us in 1990, requesting the use of a
diesel-powered electrical generator. In
1996, we determined that it was
necessary for a mine operator to petition
both §§ 75.701 and 75.901 to allow the
use of a diesel-powered electrical
generator in underground coal mines.
Petitioning both standards resulted in
additional expense and paperwork
burden for mine operators. To reduce
the expense and paperwork burden for
mine operators, we conducted a review
of both standards in 2003 and
determined that only a PFM of § 75.901
was necessary because conditions for
grounding contained in the petition will
satisfy the requirement of § 75.701 as an
approved method of grounding.
On June 25, 2004, we published a
proposed rule (69 FR 35992) to amend
the existing electrical standard § 75.901
(Protection of low- and medium-voltage
three-phase circuits used underground),
which specifies the safety requirements
for protecting low- and medium-voltage
three-phase circuits. This standard was
published in 1970 (35 FR 17890) and
has not been changed.
During November 2004, we held four
public hearings on the proposed rule in
Salt Lake City, Utah; Birmingham,
Alabama; Lexington, Kentucky; and
Morgantown, West Virginia. The posthearing comment period closed
December 10, 2004. In response to the
proposed rule we received three written
comments and oral testimony presented
at the public hearings.
Below is a discussion of the eight
categories of comments we received and
our general response to them.
1. Types of Diesel-Powered Generators
A commenter questioned whether
these generators would be classified as
heavy-duty diesel-powered equipment.
This issue is beyond the scope of this
rulemaking because it does not address
the electrical safety of grounding
circuits for diesel-powered electrical
generators. Examples of standards that
address the types of diesel generators
are § 75.1908(b) (Nonpermissible dieselpowered equipment; categories) and
§ 72.501 (Emission limits for
nonpermissible heavy-duty dieselpowered equipment, generators, and
compressors).
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II. Discussion of Comments and
Testimony Received
2. Diesel Emissions and Particulates
Several commenters raised concerns
that the proposed rule did not address
any limits for diesel emissions and
particulates emitted into the mine
atmosphere as a health risk to miners.
One commenter stated that the proposed
rule should include carbon monoxide
and nitrogen oxide monitoring on the
inby equipment operator while the
diesel generator was used to take
equipment in and out of the mine.
Another commented that the diesel
particulate emitted into the mine
atmosphere is detrimental to miner
health. These issues are beyond the
scope of this rulemaking which
addresses the electrical safety of
grounding circuits for diesel-powered
electrical generators. These issues are
addressed by other standards
concerning emissions requirements of
diesel-powered generators. Mine
operators are reminded that they are
still required to meet the requirements
of § 70.1900, (Exhaust Gas Monitoring);
and § 72.501 (Emission limits for
nonpermissible heavy-duty dieselpowered equipment, generators and
noncompressors).
During the public hearings, we
received many comments which were
not directly related to specific proposed
provisions of the low- and mediumvoltage diesel-powered electrical
generators standard. Most of the
comments were directed at enhancing
other health and safety issues of miners,
rather than addressing the electrical
safety of grounding circuits for dieselpowered electrical generators. These
comments are beyond the scope of this
rule and they are addressed by other
existing standards. We also received two
comments concerning the number of
PFMs granted and the purpose behind
the proposed rule.
3. Fire Hazards
One commenter stated that dieselpowered generators are fire hazards and
could be placed in areas where smoke
could overtake the miners. Another
commented that diesel-powered
generators are a fire hazard because the
proposed rule failed to require a fire
suppression system. We disagree with
these commenters that the use of dieselpowered electrical generators is a fire
hazard. We have found that any
previous safety concerns such as
explosion, fire, and shock hazards
initially associated with the use of
diesel-powered electrical generators
have been sufficiently addressed by
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advances in technology. Rather, we
recognize that diesel-powered electrical
generator equipment and circuit design
improvements in combination with
sensitive electrical circuit protections
actually reduce fire, explosion, and
shock hazards. Moreover, during the 13
years these diesel generators have been
approved through the use of PFM for
use in underground mines, and we have
received no reported incidents of mine
fires resulting from their use.
In addition, these issues are beyond
the scope of this rulemaking—electrical
safety of grounding circuits for dieselpowered electrical generators, and they
are addressed by other existing safety
standards. For example, § 75.380
(Escapeways; bituminous and lignite
mines) requires two separate and
distinct escapeways for miners to escape
during emergency situations in an
underground coal mine, to address any
smoke hazard. Section 75.1909(j)(3)
(Nonpermissible diesel-powered
equipment; design and performance
requirements) requires an automatic fire
suppression system to address fire
hazards. This fire suppression system
for diesel-powered equipment applies to
the diesel-powered equipment at issue
here. Finally, all other examination
requirements in 30 CFR part 75 for
diesel-powered equipment apply.
In a matter related to fire hazards of
diesel-powered generators, we received
a comment on safe operating
temperatures of equipment being
powered by the diesel generators. This
comment is beyond the scope of this
rulemaking because it does not concern
electrical safety of grounding circuits for
diesel-powered electrical generators and
is addressed generally by § 75.1725(c)
(Machinery and equipment; operation
and maintenance).
4. Moving Equipment
A commenter stated that when
equipment is being moved in or out of
the intake escapeway and the
equipment breaks down, it blocks the
intake escapeway, and an emergency
vehicle is needed on the outby side to
transport people in case of an
emergency or an accident. This
comment is beyond the scope of this
rulemaking because it does not concern
electrical safety of grounding circuits for
diesel-powered electrical generators and
is addressed by other existing standards.
For example, § 75.380 (Escapeways;
bituminous and lignite mines), requires
that escapeways, both primary and
alternate, be maintained in a travelable
condition.
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5. Maintenance of Equipment
A commenter stated that the dieselpowered generator ‘‘will be neglected
and cause serious problems just like all
the other outby equipment.’’ This issue
concerns every piece of underground
equipment and not just diesel-powered
generators. The comment, therefore, is
beyond the scope of this rulemaking,
because it does not specifically concern
the electrical safety of grounding
circuits for diesel-powered electrical
generators, and is addressed by other
existing standards under 30 CFR part
75.
6. Operation of Equipment
One commenter stated that leaving a
piece of diesel-powered equipment
unattended is unacceptable. We agree
with this commenter that it is
unacceptable to leave diesel-powered
equipment unattended. Section
75.1916(e) requires diesel-powered
equipment not be operated unattended.
In addition, § 75.1908(c) defines the
term ‘‘attended,’’ for diesel-powered
equipment (e.g., diesel-powered
generators). This comment is beyond the
scope of this rulemaking because it does
not specifically concern the electrical
safety of grounding circuits for dieselpowered electrical generators, and is
addressed by these existing standards.
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7. Petitions for Modification
One commenter stated that a
difference exists between the number of
PFMs that were granted as shown in the
preamble to the proposed rule and the
number the commenter received under
his Freedom of Information Act (FOIA)
request. We understand that a difference
exists between these numbers stated in
the preamble and the answer to his
FOIA request. This difference is not
significant for the rulemaking because
we determined the number of petitions
for this rulemaking by retrieving the
files and hand-counted the number of
granted PFMs. We stand by the number
in the proposed rule and the final rule
as the number of granted PFMs that this
rulemaking concerns.
8. Purpose of the Rule
One commenter stated that it appears
that we are more concerned about cost
savings for the operators than safety for
miners. We do not agree with this
comment. This final rule does not
reduce protections for miners
concerning the use of electrical
equipment, e.g., diesel-powered
electrical generators. In fact, this final
rule enhances miner safety by its
required design systems and testing
procedures that limit the amount of
voltage and current to which miners can
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be exposed under ground fault
conditions. These enhancements reduce
the possibility of fire, shock, or burn
hazards.
Furthermore, while this final rule will
eliminate the need for underground coal
mine operators to file PFMs if they
choose to use diesel-powered electrical
generators, it does not reduce
protections for miners. Some of the
protections in this final rule involve the
use of sensitive ground fault devices in
conjunction with a grounding resistor
that limits the ground fault current to
0.5 amps and trips the neutral
grounding resistor when a fault current
of not more than 90 milliamps is
detected by the system. These
requirements reduce the potential for
shock hazards and prevent the neutral
grounding resistor from overheating and
becoming a fire hazard.
III. Section-by-Section Discussion of the
Final Rule
Section 75.901 Protection of Low- and
Medium-Voltage Three-Phase Circuits
Used Underground
Existing § 75.901contains the
requirements for low- and mediumvoltage three-phase alternating-current
circuits used underground.
Final paragraph 75.901(b)(1) through
(12) is new and is being added to
§ 75.901 to permit the use of dieselpowered electrical generators as an
alternative to power centers for the
purpose of moving equipment in, out,
and around the mine, and for
performing work in areas where
permissible equipment is not required.
Paragraphs 75.901(b)(1) through (12) are
electrical safety standards applicable to
low- and medium-voltage dieselpowered electrical generators and
circuits.
In the proposed paragraph (b), we
inadvertently omitted the word ‘‘and’’
from the phrase ‘‘for the purpose of
moving equipment in, out, and around
the mine,’’ in the introductory
paragraph for proposed paragraphs
(b)(1) through (b)(12) as published on
June 25, 2004 (69 FR 35998). The final
rule corrects this omission and the final
paragraph now reads correctly. We did
not receive any comments on the
proposed paragraph. Therefore,
paragraph (b) of § 75.901 is finalized as
corrected.
Final paragraph (b)(1) requires the
diesel engine powering the electrical
generator to satisfy the requirements of
30 CFR part 7, subpart E. The
regulations in part 7 set out the
requirements for diesel engines
intended for use in underground coal
mines. We did not receive any
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comments on paragraph (b)(1).
Therefore, paragraph (b)(1) is
unchanged from the proposed rule.
Final paragraph (b)(2) requires a
grounding resistor which is rated for the
phase-to-phase voltage of the system to
be provided to limit the ground-fault
current to not more than 0.5 amperes.
To meet these requirements, operators
must use grounding resistor(s) in one of
the three methods provided in (b)(2)(i),
(ii) and (iii), and as illustrated in
Appendix A to subpart J. The grounding
resistor required by (b)(2)(i) must be
located between the wye-connected
generator neutral and the generator
frame; or the grounding resistors
required by (b)(2)(ii) must be located
between the wye-connected generator,
the transformer secondary and the
transformer frame, when an isolation
transformer is used; or the grounding
resistor required by (b)(2)(iii) must be
located between the wye-connected
generator neutral and the generator
frame when an auto-transformer is used.
Requiring a grounding resistor rated
for the phase-to-phase voltage of the
system will ensure that adequate
insulating properties are provided for
the grounding resistor. This is especially
important when using autotransformers. When using an autotransformer, the grounding resistor is
required to be located between the
neutral of the wye-connected generator
and the generator frame, and it must be
rated for the highest output voltage of
the auto-transformer. A wye connection
provides a neutral grounding point in
the system for the purpose of inserting
a predetermined value resistor that
would limit the current and voltage
under a phase-to-ground fault condition.
A phase-to-ground fault occurring on
the secondary side of the autotransformer would subject the
grounding resistor to the output voltage
of the autotransformer. This is because
auto-transformers have only one
winding-per-phase and do not provide
the electrical isolation characteristics
necessary to re-establish a different or
new system voltage. A resistor that is
subjected to a voltage higher than its
rating can potentially explode, causing
serious injury or death to persons
nearby, or it can open from overcurrent,
leaving the system ungrounded.
Limiting the ground-fault current to
not more than 0.5 amperes, and
providing the sensitive ground-fault
protection set forth in paragraphs (b)(3)
and (b)(4) (discussed below), provides
increased protection against explosion,
fire, and electrical shock. Because the
voltage from a diesel-powered electrical
generator may be increased or decreased
by an isolation transformer, an
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additional grounding resistor limiting
the ground-fault current to 0.5 amperes
would be required. The additional
resistor is needed to re-establish the
grounding circuit for the new power
circuit derived by the isolation
characteristics of the transformer.
For the purpose of establishing an
acceptable grounding method for
(b)(2)(ii) when an isolation transformer
is used in conjunction with a generator,
grounding resistors must be connected
between the generator wye connection
and the generator frame, and between
the isolation transformer wye
connection and the transformer frame.
The location of the grounding resistor
is critical to prevent fire and shock
hazards. Our experience has shown that
the grounding resistor has been
misplaced in some instances. Final
paragraph (b)(2) addresses this concern.
One commenter stated that
§ 75.901(b)(2), which limits the ground
fault current to 0.5 amperes, was too
restrictive and that the requirements for
diesel operation should be the same for
low- and medium-voltage electrical
equipment.
We disagree with the commenter. We
acknowledge that under § 75.901, the
present standard for low- and mediumvoltage electrical equipment typically
limits the ground fault current to 15
amps. However, when § 75.901 was
published in 1970 (35 FR 17890, Nov.
20, 1970), these sensitive ground fault
devices were not available. We have
chosen to update our electrical
standards by requiring the use of these
sensitive ground-fault devices because
the technology permits an enhanced
level of safety compared with current
standards. Also, this technology is
commercially available and used widely
in the mining industry and is an
approved grounding method under
§ 75.701.
Since the mid-1980s, the mining
industry has used grounding resistors in
resistance grounded systems to limit the
level of ground fault current in a circuit
without any reported problems. The use
of the sensitive ground fault limitation
(0.5 amps) and tripping (90 milliamps)
neutral grounding resistor in
conjunction with the ground-fault
devices specified in the proposed
standard reduces the potential for shock
hazards and prevents the neutral
grounding resistor from overheating and
becoming a fire hazard.
Under the granted PFMs, we have
required these diesel-powered
generators to have a resistor that limits
the ground fault current to 0.5 amps and
tripping at 90 milliamps. To the best of
our knowledge, mine operators are able
to acquire this technology. In addition,
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we have required that all PFMs granted
for high voltage continuous miners, high
voltage longwalls, and diesel-powered
generators have the required sensitive
ground fault limitation and tripping.
In addition, the requirements for a
sensitive ground fault limitation and
tripping in neutral grounding systems
were included in the final rule for the
installation, use, and maintenance of
high-voltage longwall mining systems
used in underground mines (67 FR
11002), and it is a requirement in the
high-voltage continuous miner proposed
rule (69 FR 42835). We have evaluated
the comment and determined that the
technology is available, is used by the
mining industry, provides enhanced
safety protection, and does not reduce
the protections afforded miners under
the current standards. Therefore, we do
not believe that the requirement is too
restrictive and the final rule retains the
proposed language except for the
following grammatical changes.
We changed the word ‘‘and’’ to ‘‘or’’
in subparagraph (b)(2)(i), ‘‘Between the
wye-connected generator neutral and
the generator frame; (see Figure I in
Appendix A to subpart J of this part), as
published on June 25, 2004 (69 FR
35998) to clarify our intent that three
methods exists to comply with the
requirements in paragraph (b)(2). With
this change, we are also changing
subparagraph (b)(2)(ii) to ‘‘Between the
wye-connected generator neutral and
the generator frame and between the
wye-connected transformer secondary
and the transformer frame when an
isolation transformer(s) is used and the
generator is supplying power to other
equipment;’’ (see Figure II in Appendix
A to subpart J of this part). These
changes are necessary to clarify our
intent that two resistors are required for
isolation transformers as stated in the
proposed rule and illustrated in the
Figure II of the proposed and final rules.
Also, in subparagraphs (b)(2)(i), (ii),
and (iii), we added hyphens between
the words ‘‘wye’’ and ‘‘connected’’ to
clarify modifiers in the placement of the
grounding resistor as published on June
25, 2004 (69 FR 35998).
Paragraph (b)(3) of the final rule
requires each three-phase output circuit
of the generator to be equipped with a
sensitive ground fault relay set to cause
the circuit interrupting device that
supplies power to the primary windings
of each transformer to trip and shut
down the diesel engine when a phaseto-frame fault of not more than 90
milliamps occurs. This maximum
current of 90 milliamps reduces the
amount of voltage to which a miner is
exposed under ground fault conditions
because the miner is in parallel with the
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grounding circuit conductors. When a
transformer is used to increase or
decrease the voltage provided by the
diesel-powered generator, the circuit
between the generator and the
transformer would be required to be
provided with grounded-phase
protection. When used in conjunction
with the grounding resistor required by
paragraph (b)(2), the increased
protection against electrical shock
assists in providing a grounding system
that satisfies the requirements of
§ 75.701.
One commenter stated that the
requirement for activation of ground
fault protective devices at 90 milliamps
fault current is too restrictive. We
disagree with the commenter. Our
response to this comment is the same as
our response above in (b)(2). The
requirement is not too restrictive; the
final rule retains the proposed language.
Final paragraph (b)(4) requires each
three-phase output circuit that supplies
power to equipment have an
instantaneous sensitive ground-fault
relay that will cause its respective
circuit interrupting device(s) to trip and
shutdown the diesel engine when a
phase-to-frame fault occurs. The rule
requires the grounded-phase protection
to be set at not more than 90 milliamps.
This protection would be provided for
all three-phase equipment circuits. This
applies to equipment receiving power
directly from the diesel-powered
electrical generator and from
transformers used to change the
generator voltage. When used in
conjunction with the grounding
resistor(s) addressed in paragraph (b)(2),
the increased protection against
electrical shock provides a grounding
system that satisfies the requirements of
§ 75.701.
The final rule also requires a single
window-type current transformer to
encircle the three-phase conductors for
ground-fault protection. The equipment
safety grounding conductors would be
prohibited from being passed through or
connected in series with the groundfault current transformers. This
configuration could defeat the groundfault protection and result in hazardous
voltages on equipment frames which
could potentially cause fatal electrical
shocks.
We did not receive any comments on
this proposed paragraph. Therefore,
paragraph (b)(4) is unchanged from the
proposed rule.
Final paragraph (b)(5) requires each
three-phase circuit interrupting device
to have a means to provide short-circuit,
overcurrent, grounded-phase,
undervoltage, and ground wire
monitoring protection. When connected
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to a piece of equipment, the
instantaneous trip unit for the circuit
interrupting device must be adjusted to
trip at not more than 75 percent of the
minimum available short circuit current
at the point where the cable enters the
equipment or the maximum allowable
instantaneous settings specified in
§ 75.601–1, whichever is less. To
determine the available short circuit
current, calculations would be required
which take into account all circuit
parameters, including the size and
length of the equipment cable. The
minimum available short circuit current
would be at the end of the maximum
length cable where it enters the
equipment. Small capacity generators
may cause the minimum available short
circuit current at the end of the
maximum length cable to be lower than
the maximum allowable settings
specified in § 75.601–1. These
requirements will ensure that proper
protection is provided for all threephase output circuits, whether at the
generator, distribution box, or at a
separate power center that receives its
primary power from a diesel-powered
electrical generator. We did not receive
any comments on the proposed
paragraph. Therefore, paragraph (b)(5) is
unchanged from the proposed rule.
Final paragraph (b)(6) requires that
the equipment portable cable length(s)
not exceed the length(s) specified in 30
CFR part 18, Appendix I, Table 9,
Specifications for Portable Cables
Longer than 500 Feet. The purpose of
this requirement is to limit the cable
length, which ensures that the short
circuit capacity of the generator is great
enough to cause the circuit interrupting
device to open, thereby preventing
damage to the cables. We did not
receive any comments on the proposed
paragraph. Therefore, paragraph (b)(6) is
unchanged from the proposed rule.
Final paragraph (b)(7) requires that
permanent label(s) listing the maximum
circuit interrupting device setting(s) and
maximum portable cable length(s) be
installed on each instantaneous trip unit
or be maintained near each three-phase
circuit interrupting device. This final
rule requires that the permanent label(s)
be maintained legibly. Because the
maximum short circuit current is
calculated using the minimum length
cable allowed; the label ensures that
adequate short circuit protection for
each circuit is provided. In addition,
other existing standards (§ 75.601 Short
circuit protection of trailing cables and
§ 75.904 Identification of circuit
breakers) require the circuit breaker,
plug, and receptacle to be labeled to
identify the equipment receiving power.
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We did not receive any comments on
the proposed paragraph. Therefore,
paragraph (b)(7) is unchanged from the
proposed rule.
Final paragraph (b)(8) requires that
only one circuit interrupting device at a
time be used when equipment is being
moved in, out, and around a mine. This
does not prevent the use of more than
one circuit when equipment is used to
perform work in areas where
permissible equipment is not required.
When multiple pieces of equipment are
used, care must be taken to ensure that
the circuit interrupting device settings
are properly adjusted to protect the
generator and the equipment being
operated.
We did not receive any comments on
the proposed paragraph. However, the
term ‘‘device’’ was inadvertently
omitted from the phrase ‘‘circuit
interrupting device’’ in proposed
paragraph (b)(8) as published on June
25, 2004 (69 FR 35998). The final rule
corrects this omission and final
paragraph (b)(8) now reads correctly.
Therefore, paragraph (b)(8) is finalized
as corrected.
Final paragraph (b)(9) refers to
existing § 75.902 (Low- and mediumvoltage ground check monitor circuits).
Section 75.902 requires the grounding
system to include an MSHA-accepted
ground wire monitor system, or other no
less effective device approved by the
Secretary or an authorized
representative of the Secretary, to assure
ground continuity between the frame of
the generator and the equipment being
moved or used, or have a No. 1/0 or
larger external grounding conductor to
bond and ground the frames of all
equipment to the frame of the generator.
The final paragraph also requires
bonding the frame of transformers and
metallic cable coupler shells back to the
frame of the generator. Grounding
equipment in this manner limits the
amount of voltage and current to which
a miner would be exposed under an
electrical fault condition and provides a
good path for current flow to activate
protective devices.
A commenter stated there was
nothing in the standards that requires
checking for loose ground connections
during the shift the generator is used.
We disagree. The final rule, like the
proposed rule, requires the use of an
MSHA-accepted ground wire monitor
system that would detect a loose ground
and cause the circuit breaker to open the
circuit and shut down the generator.
Another commenter stated that an
electric shock hazard exists in
grounding to the frame if the ground
wire to the equipment became open. We
disagree. No hazard exists because the
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proposed standard requires the use of an
MSHA-accepted ground wire monitor
system that would detect an open
grounding conductor, cause the circuit
breaker supplying power to that circuit
to open, and shut down the generator.
Lastly, two commenters stated that
while the system is a closed circuit
system, it is not a grounded system
since it is not grounded to earth. We
recognize that the system is not
intentionally connected to earth.
However, additional safety features have
been incorporated, such as sensitive
ground fault systems and ground wire
monitoring that provide equivalent
protection to assure that the standard
would provide at least the same
measure of protection as the existing
standards.
Based on the above discussion, no
changes have been made to paragraph
(b)(9). Therefore, paragraph (b)(9) is
unchanged from the proposed rule.
Final paragraph (b)(10) requires all
trailing cables extending from the
generator to equipment to comply with
§ 75.907 (Design of trailing cables for
medium-voltage circuits). Section
75.907 specifies the trailing cable design
requirements for medium voltage
circuits and also specifies that on
equipment employing cable reels, cables
without shields may be used if the
insulation is rated 2000 volts or more.
Both type cables have been used in the
coal mining industry for over 30 years
and have been proven to provide the
required protection when properly
maintained.
A commenter recommended revising
proposed § 75.901(b)(10) to allow the
use of un-shielded trailing cables from
the generator to supply approved low
voltage permissible pumps because the
packing glands the pumps were
approved with would not accommodate
the shielded cables. The final rule, as
well as the proposed rule, does not
permit diesel-powered electric
generators to be used where permissible
equipment is required. To do so could
reduce the protections afforded miners
under the current standards. Therefore,
paragraph (b)(10) is unchanged from the
proposed rule.
Final paragraph (b)(11) requires a
strain relief device on each end of the
trailing cable(s) that extends between
the generator and the piece of
equipment being powered. Although
requirements for strain relief or
clamping of cables are covered by other
standards, they are specifically required
here because the cables are likely to be
pulled to the extent of their length
during movement of equipment. This
final paragraph also applies to the
cable(s) between the diesel-powered
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generator, transformer, distribution box
and equipment. Some mobile
equipment may be capable of pulling
the distribution box when the limit of
the cable has been reached and further
pulling would strain connections of the
generator cable. This could result in
electrical arcs and faults which may
result in flash burns, or fire. We did not
receive any comments on this proposed
paragraph. Therefore, paragraph (b)(11)
of § 75.901 is unchanged from the
proposed rule.
Final paragraph (b)(12) requires that,
prior to moving each piece of equipment
or performing work, a functional test of
each ground fault and ground wire
monitor system be performed by a
qualified electrician who meets the
requirements of § 75.153 (Electrical
work; qualified person). The groundfault circuit is tested without subjecting
the circuit to an actual grounded phase
condition. This paragraph requires a
record of each test to be maintained by
the mine operator and made available to
authorized representatives of the
Secretary and to the miners in the mine.
This paragraph requires that functional
tests be performed before the equipment
begins its move from the surface to
underground, and from underground to
the surface, and movement from one
area of a mine to another, and before
work is performed by equipment in
other areas of the mine where
permissible equipment is not required.
It does not require a functional test after
momentary or incidental stoppage
during the moving process, or
repositioning of equipment while
performing work. Manufacturers of
ground fault relay devices already
provide circuitry and test methods for
their devices that allow testing to be
conducted without subjecting the power
system to an actual ground fault
condition. This method of testing
enhances safety by preventing miners
from being exposed to energized circuits
while performing the test. The
functional tests required by this
paragraph do not relieve the mine
operator of responsibility for performing
examinations and tests required by
other sections of 30 CFR part 75.
Two commenters stated that a
functional test as required by
§ 75.901(b)(12) would be necessary only
at the start of each project even if there
was a shift or multiple shifts break
before starting to use the generator again
and would be no different than a
momentary stoppage. They further
stated that the generator will be checked
on a weekly basis and required to be
maintained in a safe operating
condition. Therefore, they commented
that we should change the paragraph to
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require a functional test at the start of
each project.
We disagree with these comments.
Testing the protective devices prior to
moving equipment, except for
momentary stoppages, ensures that the
devices are functioning properly. If the
movement of the equipment is halted
for a period of time (multiple shifts), the
project has stopped and the protective
devices should be tested again when the
project is resumed. These tests take a
minimal amount of time to conduct
(minutes) and delays are negligible
when compared to the shifts or days
that the equipment has been idled. This
requirement assures that any problems,
e.g., loose grounding wire, which may
arise during movement or stoppage will
be identified and corrected so that
miners are not exposed to hazards.
Further, paragraph (b)(2) updates the
electrical requirements by providing
these protective devices to provide an
enhanced level of safety. As part of our
longstanding policy to require these
sensitive ground-fault devices, we have
included requirements to use the
manufacturers’ installed test equipment
each time these devices are activated
prior to movement of equipment or
performing work. Reducing the number
of functional tests would reduce the
protections afforded miners under the
current standards.
For these reasons, we made no
changes to paragraph (b)(12) and the
paragraph is unchanged from the
proposed rule.
Appendix A to subpart J consists of
three figures applicable to
§ 75.901(b)(2)(i), (ii) and (iii). Figure I,
applicable to § 75.901(b)(2)(i), shows the
neutral grounding resistor connected
between the wye-connected generator
neutral and the generator frame; Figure
II, applicable to § 75.901(b)(2)(ii), shows
the neutral grounding resistors
connected between the wye-connected
generator and the transformer secondary
and the transformer frame when an
isolation transformer is used. We did
not receive any comments on Figures I
and II in the proposed appendix;
therefore, Figures I and II in Appendix
A to subpart J are unchanged from the
proposed rule. Figure III, applicable to
§ 75.901(b)(iii), shows the neutral
grounding resistor connected between
the wye-connected generator neutral
and the generator frame when an autotransformer is used. We discovered an
error in Figure III, in Appendix A to
Subpart J, after the proposed rule was
published in the Federal Register.
However, this final rule corrects the
error and Figure III is correct. We did
not receive any comments on proposed
Figure III and therefore, Figure III in
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Appendix A to Subpart J is finalized as
corrected.
IV. Executive Order 12866 (Regulatory
Planning and Review and Regulatory
Flexibility Act)
Executive Order (E.O.) 12866 as
amended by E.O. 13258 requires that
regulatory agencies assess both the costs
and benefits of intended regulations. We
have fulfilled this requirement for the
final rule, and have determined that the
final rule will not have an annual effect
of $100 million or more on the
economy. Therefore, it is not an
economically significant regulatory
action pursuant to section 3(f)(1) of E.O.
12866.
The final rule will eliminate the need
for underground coal mine operators
who choose to use diesel-powered
electrical generators to file PFMs and
thereby will generate cost savings.
From January 1990 to October 2003,
63 petitions were filed to modify
§§ 75.701 and 75.901 (Grounding
requirements and protection of low- and
medium-voltage three-phase circuits
used underground). On average,
approximately five petitions were filed
during each of these years.
Mining Sectors Affected
This final rule applies to all
underground coal mines. However,
based on already filed PFMs under
§ 75.901 and § 75.701, we estimate that
an average of five underground coal
mines per year would choose to use
diesel-powered electrical generators in
their mines.
Benefits
Diesel-powered electrical generators
provide an efficient portable source of
power to move electrical equipment.
These diesel-powered electrical
generators are easily taken to areas
where power centers or other sources of
electrical power are not available to
move mobile equipment or to supply
power to other electrical equipment
needed to do work in outby areas. The
likelihood of electrical accidents will be
decreased by (1) the protective design
features associated with the dieselpowered electrical generator protective
devices, such as requiring the grounding
resistor to limit ground fault current to
0.5 amperes under a ground fault
condition; (2) requiring the sensitive
grounded phase protection device to
cause the circuit interrupting device
protecting the electrical circuits to open
and shut down the diesel-powered
generator when a fault current of not
more than 90 milliamperes is detected
by the system; and (3) equipment testing
devices and procedures that are
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designed to facilitate safe testing of the
diesel-powered electrical circuit. Miner
safety is increased with the protective
systems and testing procedures required
by the rule because they limit the
amount of voltage and current that
miners can be exposed to under a
ground fault condition and also because
they reduce the possibility of a fire,
shock, or burn hazard. Finally, the rule
contains all the necessary electrical
safety requirements developed in the
PFMs to use diesel-powered electrical
generators.
Compliance Cost Savings
Annual cost savings from the final
rule will accrue to underground coal
mine operators who choose to use
diesel-powered electrical generators
because they will no longer have to file
an average of five PFMs per year. We
project that all five affected mines will
employ between 20 to 500 workers.
The annual cost savings were derived
by using the following: a mine
supervisor, earning $57.70 per hour,
taking 8 hours to prepare a petition; a
clerical worker earning $21.82 per hour
taking 0.1 hours to copy and mail a
petition; photocopying five pages per
petition at a cost of $0.15 per page; and
postage of $1 to send the petition to
MSHA. Based on the above,
underground coal mine operators will
incur cost savings of $2,328. These
savings are derived as follows:
5 petitions × 8.0 hrs. × $57.70 per hr. .........................................................................................................................................
5 petitions × 0.1 hrs. × $21.82 per hr. .........................................................................................................................................
5 petitions × (($0.15 photocopy cost per page × 5 pages) + $1 postage per petition) ..............................................................
Feasibility
MSHA has concluded that the
requirements of the proposed rule are
both technologically and economically
feasible.
This final rule is not a technologyforcing standard and does not involve
activities on the frontiers of scientific
knowledge. The requirements of this
rulemaking are based on the terms and
conditions in granted petitions.
This rulemaking provides an annual
cost savings of $2,328 to underground
coal and metal and nonmetal mine
operators whose yearly revenues are in
the billions of dollars.
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V. Regulatory Flexibility Act
Certification
Pursuant to the Regulatory Flexibility
Act (RFA) of 1980 as amended by the
Small Business Regulatory Enforcement
Fairness Act (SBREFA), we have
analyzed the impact of the final rule on
small businesses. Further, we have
made a determination with respect to
whether or not we can certify that the
final rule will not have a significant
economic impact on a substantial
number of small entities that are
covered by this rulemaking. Under the
SBREFA amendments to the RFA, we
must include in the rule a factual basis
for this certification. If the final rule will
have a significant economic impact on
a substantial number of small entities,
we must develop a regulatory flexibility
analysis.
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Definition of a Small Mine
Under the RFA, in analyzing the
impact of a rule on small entities, we
must use the 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. We have not taken such an
action and hence are required to use the
SBA definition.
The SBA defines a small entity in the
mining industry as an establishment
with 500 or fewer employees. All mines
affected by this rulemaking fall into this
category and hence can be viewed as
sharing the special regulatory concerns
which the RFA was designed to address.
We have looked at the impacts of our
rules on a subset of mines with 500 or
fewer employees—those with fewer
than 20 employees, which we 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, their costs of
complying with MSHA rules and the
impact of MSHA rules on them will also
tend to be different. It is for this reason
that ‘‘small mines,’’ as traditionally
defined by MSHA, are of special
concern to us.
This analysis complies with the legal
requirements of the RFA for an analysis
of the impacts on ‘‘small entities’’ while
continuing our traditional definition of
‘‘small mines.’’ We conclude that we
can certify that the final rule will not
have a significant economic impact on
a substantial number of small entities
that are covered by this rulemaking. We
have determined that this is the case
both for mines affected by this
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$2,308
$11
$9
=
There are no substantive changes in
the final rule that apply to underground
coal mines that choose not to use dieselpowered electrical generators. Thus,
such mines will not incur costs nor
generate cost savings as a result of the
final rule.
=
=
=
$2,328
rulemaking with fewer than 20
employees and for mines affected by
this rulemaking with 500 or fewer
employees.
Factual Basis for Certification
Our analysis of impacts on ‘‘small
entities’’ begins with a ‘‘screening’’
analysis. The screening compares the
estimated compliance costs of a rule for
small entities in the sector affected by
the rule to the estimated revenues for
those small entities. When estimated
compliance costs are less than one
percent of the estimated revenues or are
negative (i.e., cost savings) we believe 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, it
tends to indicate that further analysis
may be warranted. Since underground
coal mine operators employing fewer
than 20 workers have not filed for a
petition to use low- and medium-voltage
diesel-powered electrical generators, we
do not expect the final rule to have any
impact on them. Therefore, the analysis
of the final rule on small entities is
based only on SBA’s small mine
definition (those having 500 or fewer
employees). Using SBA’s definition of a
small mine (those having 500 or fewer
employees) the final rule results in cost
savings of $2,328. We therefore
conclude that the final rule will not
have a significant economic impact on
a substantial number of small entities.
VI. Paperwork Reduction Act of 1995
The amendments to § 75.901 do not
introduce new paperwork requirements
on the mine operator; however, the
existing information collection
requirements are still subject to Office of
Management and Budget (OMB)
approval under the Paperwork
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Reduction Act (PRA), 44 U.S.C.
3502(13)(A). As a result of this rule, all
PFMs for § 75.901 will be superseded,
and the information collection request
for petitions for modification approved
by OMB under 1219–0065 will be
reduced. We will submit to OMB a new
information collection request for this
rule and transfer the recordkeeping
paperwork burden hours and costs.
Burden Reduction
Due to this rulemaking, mine
operators will no longer have to petition
for modification of existing § 75.901 in
order to use diesel-powered electrical
generators. Existing OMB paperwork
package 1219–0065 includes annual
burden hours and costs related to the
time it takes mine operators to prepare
and file petitions with us, including
petitions for modifications to use dieselpowered generators. As a result of this
rulemaking, the burden hours and costs
in OMB paperwork package 1219–0065
that relate to the time it takes operators
to prepare and file petitions will need
to be reduced to reflect the fact that
PFMs to use diesel-powered electrical
generators will no longer be needed.
Therefore, the burden hours and costs in
OMB paperwork package 1219–0065
should be reduced by 40.5 hours and
77735
$2,328 annually. This reduction was
derived in the following manner.
On average, five underground coal
mines are estimated to begin to use
diesel-powered electrical generators
annually. A mine supervisor, earning
$57.70 per hour, is estimated to take 8
hours to prepare a petition. On average,
a clerical worker, earning $21.82 per
hour, is estimated to take 0.1 hours to
copy and mail a petition. Each petition
is estimated to be five pages in length,
photocopy costs are $0.15 per page, and
postage is $1 for each petition. The
annual burden hour reduction and cost
savings related to preparing and filing
petitions are:
Burden Hour Reduction:
5 petitions × 8 hrs. per petition ....................................................................................................................................
5 petitions × 0.1 hrs. per petition .................................................................................................................................
=
=
40.0 hours
0.5 hours
=
40.5 hours
Burden Cost Savings:
40 hours × $57.70 wage per hr. ....................................................................................................................................
0.5 hrs. × $21.82 wage per hr. ......................................................................................................................................
5 petitions × ((5 pgs. × $0.15 per page) + ($1 postage) ...............................................................................................
=
=
=
$2,308
$11
$9
....................................................................................................................................................................................
=
$2,328
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Burden Transfer
Also included in existing PFMs of
§ 75.901 to use diesel-powered electrical
generators are operators’ recordkeeping
requirements related to performing
ground fault and ground wire monitor
system tests and making a record of
these tests. Such tests must be
conducted and records made prior to
moving each piece of equipment or
performing work. The burden hours and
costs related to such tests and records
are also included in OMB paperwork
package 1219–0065. There are 38
burden hours and $1,064 of burden
costs in the first year, 42 burden hours
and $1,176 of burden costs in the
second year, and 46 burden hours and
$1,289 of burden costs in the third year
that would be related to these tests and
records which would need to be
removed from OMB paperwork package
1219–0065 and transferred to the
paperwork package related to this rule.
The burden hours and costs were
derived as follows.
There were 16 mines operating in
2003 that have petitions to use dieselpowered electrical generators. We
assume that although five mines
annually are estimated to begin using
diesel-powered generators, there would,
on average, be three existing mines
using such equipment that would close.
Thus, each year there would be a net of
two more mines using diesel-powered
electrical generators. A mine electrician
earning $28.01 per hour, is estimated to
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take 0.25 hours to perform the ground
fault and ground wire monitor system
tests. Such tests are estimated to be
conducted six times annually. On
average, it is estimated to take the mine
electrician 0.1 hours to make a record
each time tests are conducted.
The first year burden hours and costs
related to performing ground fault and
ground wire monitor system tests and
making a record are:
18 mines × (0.25 hrs. + 0.1 hrs. for tests
and record) × 6 times per year = 38
hours
38 hours × $28.01 wage per hour =
$1,064
The second year burden hours and
costs related to performing ground fault
and ground wire monitor system tests
and making a record are:
20 mines × (0.25 hrs. + 0.1 hrs. for tests
and record) × 6 times per year = 42
hours
42 hours × $28.01 wage per hr. = $1,176
The third year burden hours and costs
related to performing ground fault and
ground wire monitor system tests and
making a record are:
22 mines × (0.25 hrs. + 0.1 hrs. for tests
and record) × 6 times per year = 46
hours.
46 hours × $28.01 wage per hr. = $1,289
VII. Other Regulatory Considerations
A. The Unfunded Mandates Reform Act
This final rule does not include any
Federal mandate that may result in
increased expenditures by State, local,
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or tribal governments; nor does it
increase private sector expenditures by
more than $100 million annually; nor
does it 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. The Treasury and General
Government Appropriations Act of
1999: Assessment of Federal
Regulations and Policies on Families
This final rule has no affect on family
well-being or stability, marital
commitment, parental rights or
authority, or income or poverty of
families and children. Accordingly,
section 654 of the Treasury and General
Government Appropriations Act of 1999
(5 U.S.C. 601 note) requires no further
agency action, analysis, or assessment.
C. Executive Order 12630: Government
Actions and Interference With
Constitutionally Protected Property
Rights
This final rule does not implement a
policy with takings implications.
Accordingly, Executive Order 12630,
Governmental Actions and Interference
with Constitutionally Protected Property
Rights, requires no further agency action
or analysis.
D. Executive Order 12988: Civil Justice
Reform
This final rule was written to provide
a clear legal standard for affected
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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 final rule
meets the applicable standards provided
in section 3 of Executive Order 12988,
Civil Justice Reform.
E. Executive Order 13045: Protection of
Children From Environmental Health
Risks and Safety Risks
This final rule has no adverse impact
on children. Accordingly, Executive
Order 13045, Protection of Children
from Environmental Health Risks and
Safety Risks, as amended by Executive
Orders 13229 and 13296, requires no
further agency action or analysis.
F. Executive Order 13132: Federalism
This final rule does not have
‘‘federalism implications,’’ because it
does 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, Executive Order 13132,
Federalism, requires no further agency
action or analysis.
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G. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
This final rule does not have ‘‘tribal
implications,’’ because it does 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, Executive Order 13175,
Consultation and Coordination with
Indian Tribal Governments, requires no
further agency action or analysis.
H. Executive Order 13211: Actions
Concerning Regulations That
Significantly Affect Energy, Supply,
Distribution, or Use
We have reviewed this final rule for
its impact on the supply, distribution,
and use of energy because it applies to
the underground coal mining sector.
Because this final rule will result in
yearly cost savings to the coal mining
industry, this final rule will neither
reduce the supply of coal nor increase
its price.
This final rule is not a ‘‘significantly
energy action,’’ because it is not ‘‘likely
to have a significant adverse effect on
the supply, distribution, or use of
energy (including a shortfall in supply,
price increases, and increased use of
foreign supplies). Accordingly,
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Executive Order 13211, Actions
Concerning Regulations That
Significantly Affect Energy Supply,
Distribution, or Use, requires no further
agency action or analysis.’’
I. Executive Order 13272: Proper
Consideration of Small Entities in
Agency Rulemaking
We have thoroughly reviewed this
final rule to assess and take appropriate
account of its potential impact on small
businesses, small governmental
jurisdictions, and small organizations.
We have determined and certified that
this final rule will not have a significant
economic impact on a substantial
number of small entities. We solicited
public comments concerning the
accuracy and completeness of this
potential impact when the rule was
proposed. We took appropriate account
of comments received relevant to the
rule’s potential impact on small entities.
Accordingly, Executive Order 13272,
Proper Consideration of Small Entities
in Agency Rulemaking, requires no
further action or analysis by us.
VIII. Petitions for Modification
On the effective date of this final rule,
all existing PFMs for diesel-powered
electrical generators granted under
§ 75.901 and/or § 75.701 will be
superseded.
List of Subjects in 30 CFR Part 75
Mine safety and health, Underground
coal mining.
Dated: December 23, 2005.
David G. Dye,
Acting Assistant Secretary of Labor for Mine
Safety and Health.
For the reasons set out in the
preamble, and under the authority of the
Federal Mine Safety and Health Act of
1977, we are amending chapter I,
subchapter O, part 75 of title 30 of the
Code of Federal Regulations as follows:
I
PART 75—MANDATORY SAFETY
STANDARDS—UNDERGROUND COAL
MINES
1. The authority citation for part 75
continues to read as follows:
I
Authority: 30 U.S.C. 811.
SUBCHAPTER O—[AMENDED]
2. Section 75.901 is amended by
adding paragraph (b) to read as follows:
I
§ 75.901 Protection of low- and mediumvoltage three-phase circuits used
underground.
*
*
*
*
*
(b) Diesel-powered electrical
generators used as an alternative to
power centers for the purpose of moving
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equipment in, out, and around the mine,
and to perform work in areas where
permissible equipment is not required,
must comply with the following:
(1) The diesel engine powering the
electrical generator must be approved
under 30 CFR part 7, subpart E.
(2) A grounding resistor rated for the
phase-to-phase voltage of the system
must be provided to limit the groundfault current to not more than 0.5
amperes. The grounding resistor(s) must
be located:
(i) Between the wye-connected
generator neutral and the generator
frame; (see Figure I in Appendix A to
subpart J of this part) or
(ii) Between the wye-connected
generator neutral and the generator
frame and between the wye-connected
transformer secondary and the
transformer frame when an isolation
transformer(s) is used and the generator
is supplying power to the other
equipment; (see Figure II in Appendix A
to subpart J of this part) or
(iii) Between the wye-connected
generator neutral and the generator
frame when an auto-transformer is used.
(see Figure III in Appendix A to subpart
J of this part)
(3) Each three-phase output circuit of
the generator must be equipped with a
sensitive ground fault relay. The
protective relay must be set to cause the
circuit interrupting device that supplies
power to the primary windings of each
transformer to trip and shut down the
diesel engine when a phase-to-frame
fault of not more than 90 milliamperes
occurs.
(4) Each three-phase output circuit
that supplies power to equipment must
be equipped with an instantaneous
sensitive ground-fault relay that will
cause its respective circuit interrupting
device(s) to trip and cause shutdown of
the diesel engine when a phase-to-frame
fault occurs. The grounded-phase
protection must be set at not more than
90 milliamps. Current transformers used
for the ground-fault protection must be
single window-type and must be
installed to encircle all three phase
conductors. Equipment safety grounding
conductors must not pass through or be
connected in series with ground-fault
current transformers.
(5) Each three-phase circuit
interrupting device must be provided
with a means to provide short-circuit,
overcurrent, grounded-phase,
undervoltage, and ground wire
monitoring protection. The
instantaneous only trip unit for the
circuit interrupting device(s) in use
must be adjusted to trip at not more
than 75 percent of the minimum
available short circuit current at the
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circuit(s) to the equipment being
powered must be limited to the use of
only one circuit interrupting device at a
time when equipment is being moved
in, out, and around the mine.
(9) The grounding system must
include an MSHA-accepted ground wire
monitor system that satisfies the
requirements of § 75.902; or have a No.
1/0 or larger external grounding
conductor to bond and ground the
frames of all equipment to the frame of
the generator.
(10) All trailing cables extending from
the generator to equipment must comply
with § 75.907.
(11) A strain relief device must be
provided on each end of the trailing
cables that extends between the
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generator and the piece of equipment
being powered.
(12) Prior to moving each piece of
equipment or performing work, a
functional test of each ground fault and
ground wire monitor system must be
performed by a qualified electrician
who meets the requirements of § 75.153.
The ground-fault circuit must be tested
without subjecting the circuit to an
actual grounded phase condition. A
record of each test must be maintained
and made available to authorized
representatives of the Secretary and to
the miners in such mine.
3. Appendix A to subpart J is added
to read as follows:
I
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point where the portable cable enters
the equipment or the maximum
allowable instantaneous settings
specified in § 75.601–1, whichever is
less.
(6) The equipment portable cable
length(s) must not exceed the length(s)
specified in 30 CFR part 18, appendix
I, table 9, Specifications for Cables
Longer than 500 Feet.
(7) Permanent label(s) listing the
maximum circuit interrupting device
setting(s) and maximum portable cable
length(s) must be installed on each
instantaneous trip unit or be maintained
near each three-phase circuit
interrupting device. The permanent
label(s) must be maintained legibly.
(8) The circuit interrupting device
that supplies three-phase power
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BILLING CODE 4510–43–C
Agencies
[Federal Register Volume 70, Number 250 (Friday, December 30, 2005)]
[Rules and Regulations]
[Pages 77728-77739]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-24625]
-----------------------------------------------------------------------
DEPARTMENT OF LABOR
Mine Safety and Health Administration
30 CFR Part 75
RIN 1219-AA98
Low- and Medium-Voltage Diesel-Powered Electrical Generators
AGENCY: Mine Safety and Health Administration (MSHA), Labor.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This final rule amends an existing safety standard to allow
the use of low- and medium-voltage diesel-powered electrical generators
as an alternative means of powering electrical equipment in underground
coal mines. The final rule eliminates the need for mine operators to
file petitions for modification to use these portable generators to
power electrical equipment and does not reduce the protections afforded
miners by the existing standards, in fact it increases protections.
EFFECTIVE DATE: February 28, 2006.
FOR FURTHER INFORMATION CONTACT: Rebecca J. Smith, Acting Director,
Office of Standards, Regulations and Variances, MSHA, 1100 Wilson
Boulevard, Arlington, Virginia 22209-3939. Ms. Smith can be reached at
smith.rebecca@dol.gov (Internet e-mail) (202-693-9443) (voice) or (202-
693-9441) (facsimile). The final rule also is available on the Internet
at https://www.msha.gov/REGSINFO.HTM.
SUPPLEMENTARY INFORMATION:
I. Background Information
We (MSHA) are amending Sec. 75.901 to permit the use of low- and
medium-voltage diesel-powered electrical generators as a means for
providing a portable source of power to move equipment in, out, and
around the mine and to perform work in areas where permissible
equipment is not required. This final rule does not reduce the
protections for miners in the current standards, but increases miner
safety by updating the electrical requirements with new commercially-
available technology so miners may use diesel-powered electrical
generators as a source of power. The final rule provides protective
systems and testing procedures to limit the amount of voltage and
current that miners can be exposed to under ground fault conditions;
thus, it reduces the possibility of a fire, shock, or burn hazard when
miners use these generators.
Furthermore, by issuing this final rule, we are responding to the
requirements of the Regulatory Flexibility Act and Executive Order
12866 that agencies review their regulations to determine their
effectiveness and to implement any changes indicated by the review that
will make the regulation more flexible and efficient for stakeholders
and small businesses. In accordance with the requirements of the Mine
Act, Sec. 101(a)(9), this final rule does not reduce the protection
afforded to miners by the existing standard.
Generally, power centers are the main means of supplying
electricity in an underground mine. Power centers are placed
underground to provide power to permanent or stationary electrical
equipment, such as belt conveyor drives, and to mining equipment on
working sections. Power centers in areas where permissible equipment is
not required are generally stationary. Mine operators use various means
to move electrical equipment and to perform work in areas where
permissible equipment is not required. In these situations, they are
unable to use power centers to energize the machines for the move
because of the excessive length of cable required to reach the power
center. If longer trailing cables are installed in order to reach
remote power centers, proper electrical protection for these low- and
medium-voltage three-phase circuits may be compromised and overheating
of, or damage to the cables may occur.
Over a 13-year period (1990-2003), through our petition for
modification (PFM) process, mine operators have been using low- and
medium-voltage diesel-powered electrical generators as an efficient
means for providing a portable source of power to move and operate
electrical equipment in areas where permissible equipment is not
required. These portable diesel-powered electrical generators are
easily taken to areas where power centers or other sources of
electrical power are not available to move mobile equipment or supply
power to other electric equipment needed to do work in outby areas.
Proper electrical protection for these low- and medium-voltage three-
phase circuits can safely be provided by portable diesel-powered
electrical generators.
Existing mandatory safety standards Sec. 75.701 (Grounding
metallic frames, casings, and other enclosures of electric equipment)
and Sec. 75.901 (Protection of low- and medium-voltage three-phase
circuits used underground), specify the grounding requirements for
electrical equipment and low- and medium-voltage three-phase circuits.
However, when using these generators, mine operators are unable to
comply with the existing electrical protection requirements of Sec.
75.901. Currently, Sec. 75.901 requires a grounding circuit to
originate from the grounded side of a grounding resistor located at a
power center. In addition, Sec. 75.901 does not address the use of a
generator frame for the purpose of grounding.
To address their inability to comply with Sec. 75.901, mine
operators file PFMs under section 101(c) of the Federal Mine Safety and
Health Act of 1977 (Mine Act). PFMs may be granted when the Secretary
determines that an alternative method of achieving the result of a
standard exists that will at all times guarantee the same measure of
protection afforded to miners under a standard, or when the application
of a standard to the mine will result in a diminution of safety to the
miners at the mine. The PFM process results in safety requirements and
procedures that are applicable only to an individual mine. Once a final
written decision pertaining to a PFM has been issued, the governing
terms and conditions contained in the decision become the mandatory
standard at the individual mine. After
[[Page 77729]]
the PFM is issued, we continue to monitor compliance with its terms and
conditions.
During the time period January 1990 through October 2003, we
granted 63 PFMs that requested the use of diesel-powered electrical
generators. These PFMs affected 56 mines.
The first petition granted for a modification of Sec. 75.901 was
submitted to us in 1990, requesting the use of a diesel-powered
electrical generator. In 1996, we determined that it was necessary for
a mine operator to petition both Sec. Sec. 75.701 and 75.901 to allow
the use of a diesel-powered electrical generator in underground coal
mines. Petitioning both standards resulted in additional expense and
paperwork burden for mine operators. To reduce the expense and
paperwork burden for mine operators, we conducted a review of both
standards in 2003 and determined that only a PFM of Sec. 75.901 was
necessary because conditions for grounding contained in the petition
will satisfy the requirement of Sec. 75.701 as an approved method of
grounding.
On June 25, 2004, we published a proposed rule (69 FR 35992) to
amend the existing electrical standard Sec. 75.901 (Protection of low-
and medium-voltage three-phase circuits used underground), which
specifies the safety requirements for protecting low- and medium-
voltage three-phase circuits. This standard was published in 1970 (35
FR 17890) and has not been changed.
During November 2004, we held four public hearings on the proposed
rule in Salt Lake City, Utah; Birmingham, Alabama; Lexington, Kentucky;
and Morgantown, West Virginia. The post-hearing comment period closed
December 10, 2004. In response to the proposed rule we received three
written comments and oral testimony presented at the public hearings.
II. Discussion of Comments and Testimony Received
During the public hearings, we received many comments which were
not directly related to specific proposed provisions of the low- and
medium-voltage diesel-powered electrical generators standard. Most of
the comments were directed at enhancing other health and safety issues
of miners, rather than addressing the electrical safety of grounding
circuits for diesel-powered electrical generators. These comments are
beyond the scope of this rule and they are addressed by other existing
standards. We also received two comments concerning the number of PFMs
granted and the purpose behind the proposed rule.
Below is a discussion of the eight categories of comments we
received and our general response to them.
1. Types of Diesel-Powered Generators
A commenter questioned whether these generators would be classified
as heavy-duty diesel-powered equipment. This issue is beyond the scope
of this rulemaking because it does not address the electrical safety of
grounding circuits for diesel-powered electrical generators. Examples
of standards that address the types of diesel generators are Sec.
75.1908(b) (Nonpermissible diesel-powered equipment; categories) and
Sec. 72.501 (Emission limits for nonpermissible heavy-duty diesel-
powered equipment, generators, and compressors).
2. Diesel Emissions and Particulates
Several commenters raised concerns that the proposed rule did not
address any limits for diesel emissions and particulates emitted into
the mine atmosphere as a health risk to miners. One commenter stated
that the proposed rule should include carbon monoxide and nitrogen
oxide monitoring on the inby equipment operator while the diesel
generator was used to take equipment in and out of the mine. Another
commented that the diesel particulate emitted into the mine atmosphere
is detrimental to miner health. These issues are beyond the scope of
this rulemaking which addresses the electrical safety of grounding
circuits for diesel-powered electrical generators. These issues are
addressed by other standards concerning emissions requirements of
diesel-powered generators. Mine operators are reminded that they are
still required to meet the requirements of Sec. 70.1900, (Exhaust Gas
Monitoring); and Sec. 72.501 (Emission limits for nonpermissible
heavy-duty diesel-powered equipment, generators and noncompressors).
3. Fire Hazards
One commenter stated that diesel-powered generators are fire
hazards and could be placed in areas where smoke could overtake the
miners. Another commented that diesel-powered generators are a fire
hazard because the proposed rule failed to require a fire suppression
system. We disagree with these commenters that the use of diesel-
powered electrical generators is a fire hazard. We have found that any
previous safety concerns such as explosion, fire, and shock hazards
initially associated with the use of diesel-powered electrical
generators have been sufficiently addressed by advances in technology.
Rather, we recognize that diesel-powered electrical generator equipment
and circuit design improvements in combination with sensitive
electrical circuit protections actually reduce fire, explosion, and
shock hazards. Moreover, during the 13 years these diesel generators
have been approved through the use of PFM for use in underground mines,
and we have received no reported incidents of mine fires resulting from
their use.
In addition, these issues are beyond the scope of this rulemaking--
electrical safety of grounding circuits for diesel-powered electrical
generators, and they are addressed by other existing safety standards.
For example, Sec. 75.380 (Escapeways; bituminous and lignite mines)
requires two separate and distinct escapeways for miners to escape
during emergency situations in an underground coal mine, to address any
smoke hazard. Section 75.1909(j)(3) (Nonpermissible diesel-powered
equipment; design and performance requirements) requires an automatic
fire suppression system to address fire hazards. This fire suppression
system for diesel-powered equipment applies to the diesel-powered
equipment at issue here. Finally, all other examination requirements in
30 CFR part 75 for diesel-powered equipment apply.
In a matter related to fire hazards of diesel-powered generators,
we received a comment on safe operating temperatures of equipment being
powered by the diesel generators. This comment is beyond the scope of
this rulemaking because it does not concern electrical safety of
grounding circuits for diesel-powered electrical generators and is
addressed generally by Sec. 75.1725(c) (Machinery and equipment;
operation and maintenance).
4. Moving Equipment
A commenter stated that when equipment is being moved in or out of
the intake escapeway and the equipment breaks down, it blocks the
intake escapeway, and an emergency vehicle is needed on the outby side
to transport people in case of an emergency or an accident. This
comment is beyond the scope of this rulemaking because it does not
concern electrical safety of grounding circuits for diesel-powered
electrical generators and is addressed by other existing standards. For
example, Sec. 75.380 (Escapeways; bituminous and lignite mines),
requires that escapeways, both primary and alternate, be maintained in
a travelable condition.
[[Page 77730]]
5. Maintenance of Equipment
A commenter stated that the diesel-powered generator ``will be
neglected and cause serious problems just like all the other outby
equipment.'' This issue concerns every piece of underground equipment
and not just diesel-powered generators. The comment, therefore, is
beyond the scope of this rulemaking, because it does not specifically
concern the electrical safety of grounding circuits for diesel-powered
electrical generators, and is addressed by other existing standards
under 30 CFR part 75.
6. Operation of Equipment
One commenter stated that leaving a piece of diesel-powered
equipment unattended is unacceptable. We agree with this commenter that
it is unacceptable to leave diesel-powered equipment unattended.
Section 75.1916(e) requires diesel-powered equipment not be operated
unattended. In addition, Sec. 75.1908(c) defines the term
``attended,'' for diesel-powered equipment (e.g., diesel-powered
generators). This comment is beyond the scope of this rulemaking
because it does not specifically concern the electrical safety of
grounding circuits for diesel-powered electrical generators, and is
addressed by these existing standards.
7. Petitions for Modification
One commenter stated that a difference exists between the number of
PFMs that were granted as shown in the preamble to the proposed rule
and the number the commenter received under his Freedom of Information
Act (FOIA) request. We understand that a difference exists between
these numbers stated in the preamble and the answer to his FOIA
request. This difference is not significant for the rulemaking because
we determined the number of petitions for this rulemaking by retrieving
the files and hand-counted the number of granted PFMs. We stand by the
number in the proposed rule and the final rule as the number of granted
PFMs that this rulemaking concerns.
8. Purpose of the Rule
One commenter stated that it appears that we are more concerned
about cost savings for the operators than safety for miners. We do not
agree with this comment. This final rule does not reduce protections
for miners concerning the use of electrical equipment, e.g., diesel-
powered electrical generators. In fact, this final rule enhances miner
safety by its required design systems and testing procedures that limit
the amount of voltage and current to which miners can be exposed under
ground fault conditions. These enhancements reduce the possibility of
fire, shock, or burn hazards.
Furthermore, while this final rule will eliminate the need for
underground coal mine operators to file PFMs if they choose to use
diesel-powered electrical generators, it does not reduce protections
for miners. Some of the protections in this final rule involve the use
of sensitive ground fault devices in conjunction with a grounding
resistor that limits the ground fault current to 0.5 amps and trips the
neutral grounding resistor when a fault current of not more than 90
milliamps is detected by the system. These requirements reduce the
potential for shock hazards and prevent the neutral grounding resistor
from overheating and becoming a fire hazard.
III. Section-by-Section Discussion of the Final Rule
Section 75.901 Protection of Low- and Medium-Voltage Three-Phase
Circuits Used Underground
Existing Sec. 75.901contains the requirements for low- and medium-
voltage three-phase alternating-current circuits used underground.
Final paragraph 75.901(b)(1) through (12) is new and is being added
to Sec. 75.901 to permit the use of diesel-powered electrical
generators as an alternative to power centers for the purpose of moving
equipment in, out, and around the mine, and for performing work in
areas where permissible equipment is not required. Paragraphs
75.901(b)(1) through (12) are electrical safety standards applicable to
low- and medium-voltage diesel-powered electrical generators and
circuits.
In the proposed paragraph (b), we inadvertently omitted the word
``and'' from the phrase ``for the purpose of moving equipment in, out,
and around the mine,'' in the introductory paragraph for proposed
paragraphs (b)(1) through (b)(12) as published on June 25, 2004 (69 FR
35998). The final rule corrects this omission and the final paragraph
now reads correctly. We did not receive any comments on the proposed
paragraph. Therefore, paragraph (b) of Sec. 75.901 is finalized as
corrected.
Final paragraph (b)(1) requires the diesel engine powering the
electrical generator to satisfy the requirements of 30 CFR part 7,
subpart E. The regulations in part 7 set out the requirements for
diesel engines intended for use in underground coal mines. We did not
receive any comments on paragraph (b)(1). Therefore, paragraph (b)(1)
is unchanged from the proposed rule.
Final paragraph (b)(2) requires a grounding resistor which is rated
for the phase-to-phase voltage of the system to be provided to limit
the ground-fault current to not more than 0.5 amperes. To meet these
requirements, operators must use grounding resistor(s) in one of the
three methods provided in (b)(2)(i), (ii) and (iii), and as illustrated
in Appendix A to subpart J. The grounding resistor required by
(b)(2)(i) must be located between the wye-connected generator neutral
and the generator frame; or the grounding resistors required by
(b)(2)(ii) must be located between the wye-connected generator, the
transformer secondary and the transformer frame, when an isolation
transformer is used; or the grounding resistor required by (b)(2)(iii)
must be located between the wye-connected generator neutral and the
generator frame when an auto-transformer is used.
Requiring a grounding resistor rated for the phase-to-phase voltage
of the system will ensure that adequate insulating properties are
provided for the grounding resistor. This is especially important when
using auto-transformers. When using an auto-transformer, the grounding
resistor is required to be located between the neutral of the wye-
connected generator and the generator frame, and it must be rated for
the highest output voltage of the auto-transformer. A wye connection
provides a neutral grounding point in the system for the purpose of
inserting a predetermined value resistor that would limit the current
and voltage under a phase-to-ground fault condition. A phase-to-ground
fault occurring on the secondary side of the auto-transformer would
subject the grounding resistor to the output voltage of the
autotransformer. This is because auto-transformers have only one
winding-per-phase and do not provide the electrical isolation
characteristics necessary to re-establish a different or new system
voltage. A resistor that is subjected to a voltage higher than its
rating can potentially explode, causing serious injury or death to
persons nearby, or it can open from overcurrent, leaving the system
ungrounded.
Limiting the ground-fault current to not more than 0.5 amperes, and
providing the sensitive ground-fault protection set forth in paragraphs
(b)(3) and (b)(4) (discussed below), provides increased protection
against explosion, fire, and electrical shock. Because the voltage from
a diesel-powered electrical generator may be increased or decreased by
an isolation transformer, an
[[Page 77731]]
additional grounding resistor limiting the ground-fault current to 0.5
amperes would be required. The additional resistor is needed to re-
establish the grounding circuit for the new power circuit derived by
the isolation characteristics of the transformer.
For the purpose of establishing an acceptable grounding method for
(b)(2)(ii) when an isolation transformer is used in conjunction with a
generator, grounding resistors must be connected between the generator
wye connection and the generator frame, and between the isolation
transformer wye connection and the transformer frame.
The location of the grounding resistor is critical to prevent fire
and shock hazards. Our experience has shown that the grounding resistor
has been misplaced in some instances. Final paragraph (b)(2) addresses
this concern.
One commenter stated that Sec. 75.901(b)(2), which limits the
ground fault current to 0.5 amperes, was too restrictive and that the
requirements for diesel operation should be the same for low- and
medium-voltage electrical equipment.
We disagree with the commenter. We acknowledge that under Sec.
75.901, the present standard for low- and medium-voltage electrical
equipment typically limits the ground fault current to 15 amps.
However, when Sec. 75.901 was published in 1970 (35 FR 17890, Nov. 20,
1970), these sensitive ground fault devices were not available. We have
chosen to update our electrical standards by requiring the use of these
sensitive ground-fault devices because the technology permits an
enhanced level of safety compared with current standards. Also, this
technology is commercially available and used widely in the mining
industry and is an approved grounding method under Sec. 75.701.
Since the mid-1980s, the mining industry has used grounding
resistors in resistance grounded systems to limit the level of ground
fault current in a circuit without any reported problems. The use of
the sensitive ground fault limitation (0.5 amps) and tripping (90
milliamps) neutral grounding resistor in conjunction with the ground-
fault devices specified in the proposed standard reduces the potential
for shock hazards and prevents the neutral grounding resistor from
overheating and becoming a fire hazard.
Under the granted PFMs, we have required these diesel-powered
generators to have a resistor that limits the ground fault current to
0.5 amps and tripping at 90 milliamps. To the best of our knowledge,
mine operators are able to acquire this technology. In addition, we
have required that all PFMs granted for high voltage continuous miners,
high voltage longwalls, and diesel-powered generators have the required
sensitive ground fault limitation and tripping.
In addition, the requirements for a sensitive ground fault
limitation and tripping in neutral grounding systems were included in
the final rule for the installation, use, and maintenance of high-
voltage longwall mining systems used in underground mines (67 FR
11002), and it is a requirement in the high-voltage continuous miner
proposed rule (69 FR 42835). We have evaluated the comment and
determined that the technology is available, is used by the mining
industry, provides enhanced safety protection, and does not reduce the
protections afforded miners under the current standards. Therefore, we
do not believe that the requirement is too restrictive and the final
rule retains the proposed language except for the following grammatical
changes.
We changed the word ``and'' to ``or'' in subparagraph (b)(2)(i),
``Between the wye-connected generator neutral and the generator frame;
(see Figure I in Appendix A to subpart J of this part), as published on
June 25, 2004 (69 FR 35998) to clarify our intent that three methods
exists to comply with the requirements in paragraph (b)(2). With this
change, we are also changing subparagraph (b)(2)(ii) to ``Between the
wye-connected generator neutral and the generator frame and between the
wye-connected transformer secondary and the transformer frame when an
isolation transformer(s) is used and the generator is supplying power
to other equipment;'' (see Figure II in Appendix A to subpart J of this
part). These changes are necessary to clarify our intent that two
resistors are required for isolation transformers as stated in the
proposed rule and illustrated in the Figure II of the proposed and
final rules.
Also, in subparagraphs (b)(2)(i), (ii), and (iii), we added hyphens
between the words ``wye'' and ``connected'' to clarify modifiers in the
placement of the grounding resistor as published on June 25, 2004 (69
FR 35998).
Paragraph (b)(3) of the final rule requires each three-phase output
circuit of the generator to be equipped with a sensitive ground fault
relay set to cause the circuit interrupting device that supplies power
to the primary windings of each transformer to trip and shut down the
diesel engine when a phase-to-frame fault of not more than 90 milliamps
occurs. This maximum current of 90 milliamps reduces the amount of
voltage to which a miner is exposed under ground fault conditions
because the miner is in parallel with the grounding circuit conductors.
When a transformer is used to increase or decrease the voltage provided
by the diesel-powered generator, the circuit between the generator and
the transformer would be required to be provided with grounded-phase
protection. When used in conjunction with the grounding resistor
required by paragraph (b)(2), the increased protection against
electrical shock assists in providing a grounding system that satisfies
the requirements of Sec. 75.701.
One commenter stated that the requirement for activation of ground
fault protective devices at 90 milliamps fault current is too
restrictive. We disagree with the commenter. Our response to this
comment is the same as our response above in (b)(2). The requirement is
not too restrictive; the final rule retains the proposed language.
Final paragraph (b)(4) requires each three-phase output circuit
that supplies power to equipment have an instantaneous sensitive
ground-fault relay that will cause its respective circuit interrupting
device(s) to trip and shutdown the diesel engine when a phase-to-frame
fault occurs. The rule requires the grounded-phase protection to be set
at not more than 90 milliamps. This protection would be provided for
all three-phase equipment circuits. This applies to equipment receiving
power directly from the diesel-powered electrical generator and from
transformers used to change the generator voltage. When used in
conjunction with the grounding resistor(s) addressed in paragraph
(b)(2), the increased protection against electrical shock provides a
grounding system that satisfies the requirements of Sec. 75.701.
The final rule also requires a single window-type current
transformer to encircle the three-phase conductors for ground-fault
protection. The equipment safety grounding conductors would be
prohibited from being passed through or connected in series with the
ground-fault current transformers. This configuration could defeat the
ground-fault protection and result in hazardous voltages on equipment
frames which could potentially cause fatal electrical shocks.
We did not receive any comments on this proposed paragraph.
Therefore, paragraph (b)(4) is unchanged from the proposed rule.
Final paragraph (b)(5) requires each three-phase circuit
interrupting device to have a means to provide short-circuit,
overcurrent, grounded-phase, undervoltage, and ground wire monitoring
protection. When connected
[[Page 77732]]
to a piece of equipment, the instantaneous trip unit for the circuit
interrupting device must be adjusted to trip at not more than 75
percent of the minimum available short circuit current at the point
where the cable enters the equipment or the maximum allowable
instantaneous settings specified in Sec. 75.601-1, whichever is less.
To determine the available short circuit current, calculations would be
required which take into account all circuit parameters, including the
size and length of the equipment cable. The minimum available short
circuit current would be at the end of the maximum length cable where
it enters the equipment. Small capacity generators may cause the
minimum available short circuit current at the end of the maximum
length cable to be lower than the maximum allowable settings specified
in Sec. 75.601-1. These requirements will ensure that proper
protection is provided for all three-phase output circuits, whether at
the generator, distribution box, or at a separate power center that
receives its primary power from a diesel-powered electrical generator.
We did not receive any comments on the proposed paragraph. Therefore,
paragraph (b)(5) is unchanged from the proposed rule.
Final paragraph (b)(6) requires that the equipment portable cable
length(s) not exceed the length(s) specified in 30 CFR part 18,
Appendix I, Table 9, Specifications for Portable Cables Longer than 500
Feet. The purpose of this requirement is to limit the cable length,
which ensures that the short circuit capacity of the generator is great
enough to cause the circuit interrupting device to open, thereby
preventing damage to the cables. We did not receive any comments on the
proposed paragraph. Therefore, paragraph (b)(6) is unchanged from the
proposed rule.
Final paragraph (b)(7) requires that permanent label(s) listing the
maximum circuit interrupting device setting(s) and maximum portable
cable length(s) be installed on each instantaneous trip unit or be
maintained near each three-phase circuit interrupting device. This
final rule requires that the permanent label(s) be maintained legibly.
Because the maximum short circuit current is calculated using the
minimum length cable allowed; the label ensures that adequate short
circuit protection for each circuit is provided. In addition, other
existing standards (Sec. 75.601 Short circuit protection of trailing
cables and Sec. 75.904 Identification of circuit breakers) require the
circuit breaker, plug, and receptacle to be labeled to identify the
equipment receiving power.
We did not receive any comments on the proposed paragraph.
Therefore, paragraph (b)(7) is unchanged from the proposed rule.
Final paragraph (b)(8) requires that only one circuit interrupting
device at a time be used when equipment is being moved in, out, and
around a mine. This does not prevent the use of more than one circuit
when equipment is used to perform work in areas where permissible
equipment is not required. When multiple pieces of equipment are used,
care must be taken to ensure that the circuit interrupting device
settings are properly adjusted to protect the generator and the
equipment being operated.
We did not receive any comments on the proposed paragraph. However,
the term ``device'' was inadvertently omitted from the phrase ``circuit
interrupting device'' in proposed paragraph (b)(8) as published on June
25, 2004 (69 FR 35998). The final rule corrects this omission and final
paragraph (b)(8) now reads correctly. Therefore, paragraph (b)(8) is
finalized as corrected.
Final paragraph (b)(9) refers to existing Sec. 75.902 (Low- and
medium-voltage ground check monitor circuits). Section 75.902 requires
the grounding system to include an MSHA-accepted ground wire monitor
system, or other no less effective device approved by the Secretary or
an authorized representative of the Secretary, to assure ground
continuity between the frame of the generator and the equipment being
moved or used, or have a No. 1/0 or larger external grounding conductor
to bond and ground the frames of all equipment to the frame of the
generator. The final paragraph also requires bonding the frame of
transformers and metallic cable coupler shells back to the frame of the
generator. Grounding equipment in this manner limits the amount of
voltage and current to which a miner would be exposed under an
electrical fault condition and provides a good path for current flow to
activate protective devices.
A commenter stated there was nothing in the standards that requires
checking for loose ground connections during the shift the generator is
used. We disagree. The final rule, like the proposed rule, requires the
use of an MSHA-accepted ground wire monitor system that would detect a
loose ground and cause the circuit breaker to open the circuit and shut
down the generator.
Another commenter stated that an electric shock hazard exists in
grounding to the frame if the ground wire to the equipment became open.
We disagree. No hazard exists because the proposed standard requires
the use of an MSHA-accepted ground wire monitor system that would
detect an open grounding conductor, cause the circuit breaker supplying
power to that circuit to open, and shut down the generator.
Lastly, two commenters stated that while the system is a closed
circuit system, it is not a grounded system since it is not grounded to
earth. We recognize that the system is not intentionally connected to
earth. However, additional safety features have been incorporated, such
as sensitive ground fault systems and ground wire monitoring that
provide equivalent protection to assure that the standard would provide
at least the same measure of protection as the existing standards.
Based on the above discussion, no changes have been made to
paragraph (b)(9). Therefore, paragraph (b)(9) is unchanged from the
proposed rule.
Final paragraph (b)(10) requires all trailing cables extending from
the generator to equipment to comply with Sec. 75.907 (Design of
trailing cables for medium-voltage circuits). Section 75.907 specifies
the trailing cable design requirements for medium voltage circuits and
also specifies that on equipment employing cable reels, cables without
shields may be used if the insulation is rated 2000 volts or more. Both
type cables have been used in the coal mining industry for over 30
years and have been proven to provide the required protection when
properly maintained.
A commenter recommended revising proposed Sec. 75.901(b)(10) to
allow the use of un-shielded trailing cables from the generator to
supply approved low voltage permissible pumps because the packing
glands the pumps were approved with would not accommodate the shielded
cables. The final rule, as well as the proposed rule, does not permit
diesel-powered electric generators to be used where permissible
equipment is required. To do so could reduce the protections afforded
miners under the current standards. Therefore, paragraph (b)(10) is
unchanged from the proposed rule.
Final paragraph (b)(11) requires a strain relief device on each end
of the trailing cable(s) that extends between the generator and the
piece of equipment being powered. Although requirements for strain
relief or clamping of cables are covered by other standards, they are
specifically required here because the cables are likely to be pulled
to the extent of their length during movement of equipment. This final
paragraph also applies to the cable(s) between the diesel-powered
[[Page 77733]]
generator, transformer, distribution box and equipment. Some mobile
equipment may be capable of pulling the distribution box when the limit
of the cable has been reached and further pulling would strain
connections of the generator cable. This could result in electrical
arcs and faults which may result in flash burns, or fire. We did not
receive any comments on this proposed paragraph. Therefore, paragraph
(b)(11) of Sec. 75.901 is unchanged from the proposed rule.
Final paragraph (b)(12) requires that, prior to moving each piece
of equipment or performing work, a functional test of each ground fault
and ground wire monitor system be performed by a qualified electrician
who meets the requirements of Sec. 75.153 (Electrical work; qualified
person). The ground-fault circuit is tested without subjecting the
circuit to an actual grounded phase condition. This paragraph requires
a record of each test to be maintained by the mine operator and made
available to authorized representatives of the Secretary and to the
miners in the mine. This paragraph requires that functional tests be
performed before the equipment begins its move from the surface to
underground, and from underground to the surface, and movement from one
area of a mine to another, and before work is performed by equipment in
other areas of the mine where permissible equipment is not required. It
does not require a functional test after momentary or incidental
stoppage during the moving process, or repositioning of equipment while
performing work. Manufacturers of ground fault relay devices already
provide circuitry and test methods for their devices that allow testing
to be conducted without subjecting the power system to an actual ground
fault condition. This method of testing enhances safety by preventing
miners from being exposed to energized circuits while performing the
test. The functional tests required by this paragraph do not relieve
the mine operator of responsibility for performing examinations and
tests required by other sections of 30 CFR part 75.
Two commenters stated that a functional test as required by Sec.
75.901(b)(12) would be necessary only at the start of each project even
if there was a shift or multiple shifts break before starting to use
the generator again and would be no different than a momentary
stoppage. They further stated that the generator will be checked on a
weekly basis and required to be maintained in a safe operating
condition. Therefore, they commented that we should change the
paragraph to require a functional test at the start of each project.
We disagree with these comments. Testing the protective devices
prior to moving equipment, except for momentary stoppages, ensures that
the devices are functioning properly. If the movement of the equipment
is halted for a period of time (multiple shifts), the project has
stopped and the protective devices should be tested again when the
project is resumed. These tests take a minimal amount of time to
conduct (minutes) and delays are negligible when compared to the shifts
or days that the equipment has been idled. This requirement assures
that any problems, e.g., loose grounding wire, which may arise during
movement or stoppage will be identified and corrected so that miners
are not exposed to hazards.
Further, paragraph (b)(2) updates the electrical requirements by
providing these protective devices to provide an enhanced level of
safety. As part of our longstanding policy to require these sensitive
ground-fault devices, we have included requirements to use the
manufacturers' installed test equipment each time these devices are
activated prior to movement of equipment or performing work. Reducing
the number of functional tests would reduce the protections afforded
miners under the current standards.
For these reasons, we made no changes to paragraph (b)(12) and the
paragraph is unchanged from the proposed rule.
Appendix A to subpart J consists of three figures applicable to
Sec. 75.901(b)(2)(i), (ii) and (iii). Figure I, applicable to Sec.
75.901(b)(2)(i), shows the neutral grounding resistor connected between
the wye-connected generator neutral and the generator frame; Figure II,
applicable to Sec. 75.901(b)(2)(ii), shows the neutral grounding
resistors connected between the wye-connected generator and the
transformer secondary and the transformer frame when an isolation
transformer is used. We did not receive any comments on Figures I and
II in the proposed appendix; therefore, Figures I and II in Appendix A
to subpart J are unchanged from the proposed rule. Figure III,
applicable to Sec. 75.901(b)(iii), shows the neutral grounding
resistor connected between the wye-connected generator neutral and the
generator frame when an auto-transformer is used. We discovered an
error in Figure III, in Appendix A to Subpart J, after the proposed
rule was published in the Federal Register. However, this final rule
corrects the error and Figure III is correct. We did not receive any
comments on proposed Figure III and therefore, Figure III in Appendix A
to Subpart J is finalized as corrected.
IV. Executive Order 12866 (Regulatory Planning and Review and
Regulatory Flexibility Act)
Executive Order (E.O.) 12866 as amended by E.O. 13258 requires that
regulatory agencies assess both the costs and benefits of intended
regulations. We have fulfilled this requirement for the final rule, and
have determined that the final rule will not have an annual effect of
$100 million or more on the economy. Therefore, it is not an
economically significant regulatory action pursuant to section 3(f)(1)
of E.O. 12866.
The final rule will eliminate the need for underground coal mine
operators who choose to use diesel-powered electrical generators to
file PFMs and thereby will generate cost savings.
From January 1990 to October 2003, 63 petitions were filed to
modify Sec. Sec. 75.701 and 75.901 (Grounding requirements and
protection of low- and medium-voltage three-phase circuits used
underground). On average, approximately five petitions were filed
during each of these years.
Mining Sectors Affected
This final rule applies to all underground coal mines. However,
based on already filed PFMs under Sec. 75.901 and Sec. 75.701, we
estimate that an average of five underground coal mines per year would
choose to use diesel-powered electrical generators in their mines.
Benefits
Diesel-powered electrical generators provide an efficient portable
source of power to move electrical equipment. These diesel-powered
electrical generators are easily taken to areas where power centers or
other sources of electrical power are not available to move mobile
equipment or to supply power to other electrical equipment needed to do
work in outby areas. The likelihood of electrical accidents will be
decreased by (1) the protective design features associated with the
diesel-powered electrical generator protective devices, such as
requiring the grounding resistor to limit ground fault current to 0.5
amperes under a ground fault condition; (2) requiring the sensitive
grounded phase protection device to cause the circuit interrupting
device protecting the electrical circuits to open and shut down the
diesel-powered generator when a fault current of not more than 90
milliamperes is detected by the system; and (3) equipment testing
devices and procedures that are
[[Page 77734]]
designed to facilitate safe testing of the diesel-powered electrical
circuit. Miner safety is increased with the protective systems and
testing procedures required by the rule because they limit the amount
of voltage and current that miners can be exposed to under a ground
fault condition and also because they reduce the possibility of a fire,
shock, or burn hazard. Finally, the rule contains all the necessary
electrical safety requirements developed in the PFMs to use diesel-
powered electrical generators.
Compliance Cost Savings
Annual cost savings from the final rule will accrue to underground
coal mine operators who choose to use diesel-powered electrical
generators because they will no longer have to file an average of five
PFMs per year. We project that all five affected mines will employ
between 20 to 500 workers.
The annual cost savings were derived by using the following: a mine
supervisor, earning $57.70 per hour, taking 8 hours to prepare a
petition; a clerical worker earning $21.82 per hour taking 0.1 hours to
copy and mail a petition; photocopying five pages per petition at a
cost of $0.15 per page; and postage of $1 to send the petition to MSHA.
Based on the above, underground coal mine operators will incur cost
savings of $2,328. These savings are derived as follows:
5 petitions x 8.0 hrs. x $57.70 per hr................ = $2,308
5 petitions x 0.1 hrs. x $21.82 per hr................ = $11
5 petitions x (($0.15 photocopy cost per page x 5 = $9
pages) + $1 postage per petition)....................
------------
= $2,328
There are no substantive changes in the final rule that apply to
underground coal mines that choose not to use diesel-powered electrical
generators. Thus, such mines will not incur costs nor generate cost
savings as a result of the final rule.
Feasibility
MSHA has concluded that the requirements of the proposed rule are
both technologically and economically feasible.
This final rule is not a technology-forcing standard and does not
involve activities on the frontiers of scientific knowledge. The
requirements of this rulemaking are based on the terms and conditions
in granted petitions.
This rulemaking provides an annual cost savings of $2,328 to
underground coal and metal and nonmetal mine operators whose yearly
revenues are in the billions of dollars.
V. Regulatory Flexibility Act Certification
Pursuant to the Regulatory Flexibility Act (RFA) of 1980 as amended
by the Small Business Regulatory Enforcement Fairness Act (SBREFA), we
have analyzed the impact of the final rule on small businesses.
Further, we have made a determination with respect to whether or not we
can certify that the final rule will not have a significant economic
impact on a substantial number of small entities that are covered by
this rulemaking. Under the SBREFA amendments to the RFA, we must
include in the rule a factual basis for this certification. If the
final rule will have a significant economic impact on a substantial
number of small entities, we must develop a regulatory flexibility
analysis.
Definition of a Small Mine
Under the RFA, in analyzing the impact of a rule on small entities,
we must use the 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. We have not taken such an
action and hence are required to use the SBA definition.
The SBA defines a small entity in the mining industry as an
establishment with 500 or fewer employees. All mines affected by this
rulemaking fall into this category and hence can be viewed as sharing
the special regulatory concerns which the RFA was designed to address.
We have looked at the impacts of our rules on a subset of mines
with 500 or fewer employees--those with fewer than 20 employees, which
we 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, their costs of complying with MSHA rules and the
impact of MSHA rules on them will also tend to be different. It is for
this reason that ``small mines,'' as traditionally defined by MSHA, are
of special concern to us.
This analysis complies with the legal requirements of the RFA for
an analysis of the impacts on ``small entities'' while continuing our
traditional definition of ``small mines.'' We conclude that we can
certify that the final rule will not have a significant economic impact
on a substantial number of small entities that are covered by this
rulemaking. We have determined that this is the case both for mines
affected by this rulemaking with fewer than 20 employees and for mines
affected by this rulemaking with 500 or fewer employees.
Factual Basis for Certification
Our analysis of impacts on ``small entities'' begins with a
``screening'' analysis. The screening compares the estimated compliance
costs of a rule for small entities in the sector affected by the rule
to the estimated revenues for those small entities. When estimated
compliance costs are less than one percent of the estimated revenues or
are negative (i.e., cost savings) we believe 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, it tends to indicate that further
analysis may be warranted. Since underground coal mine operators
employing fewer than 20 workers have not filed for a petition to use
low- and medium-voltage diesel-powered electrical generators, we do not
expect the final rule to have any impact on them. Therefore, the
analysis of the final rule on small entities is based only on SBA's
small mine definition (those having 500 or fewer employees). Using
SBA's definition of a small mine (those having 500 or fewer employees)
the final rule results in cost savings of $2,328. We therefore conclude
that the final rule will not have a significant economic impact on a
substantial number of small entities.
VI. Paperwork Reduction Act of 1995
The amendments to Sec. 75.901 do not introduce new paperwork
requirements on the mine operator; however, the existing information
collection requirements are still subject to Office of Management and
Budget (OMB) approval under the Paperwork
[[Page 77735]]
Reduction Act (PRA), 44 U.S.C. 3502(13)(A). As a result of this rule,
all PFMs for Sec. 75.901 will be superseded, and the information
collection request for petitions for modification approved by OMB under
1219-0065 will be reduced. We will submit to OMB a new information
collection request for this rule and transfer the recordkeeping
paperwork burden hours and costs.
Burden Reduction
Due to this rulemaking, mine operators will no longer have to
petition for modification of existing Sec. 75.901 in order to use
diesel-powered electrical generators. Existing OMB paperwork package
1219-0065 includes annual burden hours and costs related to the time it
takes mine operators to prepare and file petitions with us, including
petitions for modifications to use diesel-powered generators. As a
result of this rulemaking, the burden hours and costs in OMB paperwork
package 1219-0065 that relate to the time it takes operators to prepare
and file petitions will need to be reduced to reflect the fact that
PFMs to use diesel-powered electrical generators will no longer be
needed. Therefore, the burden hours and costs in OMB paperwork package
1219-0065 should be reduced by 40.5 hours and $2,328 annually. This
reduction was derived in the following manner.
On average, five underground coal mines are estimated to begin to
use diesel-powered electrical generators annually. A mine supervisor,
earning $57.70 per hour, is estimated to take 8 hours to prepare a
petition. On average, a clerical worker, earning $21.82 per hour, is
estimated to take 0.1 hours to copy and mail a petition. Each petition
is estimated to be five pages in length, photocopy costs are $0.15 per
page, and postage is $1 for each petition. The annual burden hour
reduction and cost savings related to preparing and filing petitions
are:
Burden Hour Reduction:
5 petitions x 8 hrs. per petition............ = 40.0 hours
5 petitions x 0.1 hrs. per petition.......... = 0.5 hours
-----------------
= 40.5 hours
Burden Cost Savings:
40 hours x $57.70 wage per hr................ = $2,308
0.5 hrs. x $21.82 wage per hr................ = $11
5 petitions x ((5 pgs. x $0.15 per page) + = $9
($1 postage)................................
-----------------
= $2,328
Burden Transfer
Also included in existing PFMs of Sec. 75.901 to use diesel-
powered electrical generators are operators' recordkeeping requirements
related to performing ground fault and ground wire monitor system tests
and making a record of these tests. Such tests must be conducted and
records made prior to moving each piece of equipment or performing
work. The burden hours and costs related to such tests and records are
also included in OMB paperwork package 1219-0065. There are 38 burden
hours and $1,064 of burden costs in the first year, 42 burden hours and
$1,176 of burden costs in the second year, and 46 burden hours and
$1,289 of burden costs in the third year that would be related to these
tests and records which would need to be removed from OMB paperwork
package 1219-0065 and transferred to the paperwork package related to
this rule. The burden hours and costs were derived as follows.
There were 16 mines operating in 2003 that have petitions to use
diesel-powered electrical generators. We assume that although five
mines annually are estimated to begin using diesel-powered generators,
there would, on average, be three existing mines using such equipment
that would close. Thus, each year there would be a net of two more
mines using diesel-powered electrical generators. A mine electrician
earning $28.01 per hour, is estimated to take 0.25 hours to perform the
ground fault and ground wire monitor system tests. Such tests are
estimated to be conducted six times annually. On average, it is
estimated to take the mine electrician 0.1 hours to make a record each
time tests are conducted.
The first year burden hours and costs related to performing ground
fault and ground wire monitor system tests and making a record are:
18 mines x (0.25 hrs. + 0.1 hrs. for tests and record) x 6 times per
year = 38 hours
38 hours x $28.01 wage per hour = $1,064
The second year burden hours and costs related to performing ground
fault and ground wire monitor system tests and making a record are:
20 mines x (0.25 hrs. + 0.1 hrs. for tests and record) x 6 times per
year = 42 hours
42 hours x $28.01 wage per hr. = $1,176
The third year burden hours and costs related to performing ground
fault and ground wire monitor system tests and making a record are:
22 mines x (0.25 hrs. + 0.1 hrs. for tests and record) x 6 times per
year = 46 hours.
46 hours x $28.01 wage per hr. = $1,289
VII. Other Regulatory Considerations
A. The Unfunded Mandates Reform Act
This final rule does not include any Federal mandate that may
result in increased expenditures by State, local, or tribal
governments; nor does it increase private sector expenditures by more
than $100 million annually; nor does it 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. The Treasury and General Government Appropriations Act of 1999:
Assessment of Federal Regulations and Policies on Families
This final rule has no affect on family well-being or stability,
marital commitment, parental rights or authority, or income or poverty
of families and children. Accordingly, section 654 of the Treasury and
General Government Appropriations Act of 1999 (5 U.S.C. 601 note)
requires no further agency action, analysis, or assessment.
C. Executive Order 12630: Government Actions and Interference With
Constitutionally Protected Property Rights
This final rule does not implement a policy with takings
implications. Accordingly, Executive Order 12630, Governmental Actions
and Interference with Constitutionally Protected Property Rights,
requires no further agency action or analysis.
D. Executive Order 12988: Civil Justice Reform
This final rule was written to provide a clear legal standard for
affected
[[Page 77736]]
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 final rule meets the applicable
standards provided in section 3 of Executive Order 12988, Civil Justice
Reform.
E. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
This final rule has no adverse impact on children. Accordingly,
Executive Order 13045, Protection of Children from Environmental Health
Risks and Safety Risks, as amended by Executive Orders 13229 and 13296,
requires no further agency action or analysis.
F. Executive Order 13132: Federalism
This final rule does not have ``federalism implications,'' because
it does 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, Executive Order 13132, Federalism, requires
no further agency action or analysis.
G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This final rule does not have ``tribal implications,'' because it
does 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, Executive
Order 13175, Consultation and Coordination with Indian Tribal
Governments, requires no further agency action or analysis.
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy, Supply, Distribution, or Use
We have reviewed this final rule for its impact on the supply,
distribution, and use of energy because it applies to the underground
coal mining sector. Because this final rule will result in yearly cost
savings to the coal mining industry, this final rule will neither
reduce the supply of coal nor increase its price.
This final rule is not a ``significantly energy action,'' because
it is not ``likely to have a significant adverse effect on the supply,
distribution, or use of energy (including a shortfall in supply, price
increases, and increased use of foreign supplies). Accordingly,
Executive Order 13211, Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use, requires no
further agency action or analysis.''
I. Executive Order 13272: Proper Consideration of Small Entities in
Agency Rulemaking
We have thoroughly reviewed this final rule to assess and take
appropriate account of its potential impact on small businesses, small
governmental jurisdictions, and small organizations. We have determined
and certified that this final rule will not have a significant economic
impact on a substantial number of small entities. We solicited public
comments concerning the accuracy and completeness of this potential
impact when the rule was proposed. We took appropriate account of
comments received relevant to the rule's potential impact on small
entities. Accordingly, Executive Order 13272, Proper Consideration of
Small Entities in Agency Rulemaking, requires no further action or
analysis by us.
VIII. Petitions for Modification
On the effective date of this final rule, all existing PFMs for
diesel-powered electrical generators granted under Sec. 75.901 and/or
Sec. 75.701 will be superseded.
List of Subjects in 30 CFR Part 75
Mine safety and health, Underground coal mining.
Dated: December 23, 2005.
David G. Dye,
Acting Assistant Secretary of Labor for Mine Safety and Health.
0
For the reasons set out in the preamble, and under the authority of the
Federal Mine Safety and Health Act of 1977, we are amending chapter I,
subchapter O, part 75 of title 30 of the Code of Federal Regulations as
follows:
PART 75--MANDATORY SAFETY STANDARDS--UNDERGROUND COAL MINES
0
1. The authority citation for part 75 continues to read as follows:
Authority: 30 U.S.C. 811.
SUBCHAPTER O--[AMENDED]
0
2. Section 75.901 is amended by adding paragraph (b) to read as
follows:
Sec. 75.901 Protection of low- and medium-voltage three-phase
circuits used underground.
* * * * *
(b) Diesel-powered electrical generators used as an alternative to
power centers for the purpose of moving equipment in, out, and around
the mine, and to perform work in areas where permissible equipment is
not required, must comply with the following:
(1) The diesel engine powering the electrical generator must be
approved under 30 CFR part 7, subpart E.
(2) A grounding resistor rated for the phase-to-phase voltage of
the system must be provided to limit the ground-fault current to not
more than 0.5 amperes. The grounding resistor(s) must be located:
(i) Between the wye-connected generator neutral and the generator
frame; (see Figure I in Appendix A to subpart J of this part) or
(ii) Between the wye-connected generator neutral and the generator
frame and between the wye-connected transformer secondary and the
transformer frame when an isolation transformer(s) is used and the
generator is supplying power to the other equipment; (see Figure II in
Appendix A to subpart J of this part) or
(iii) Between the wye-connected generator neutral and the generator
frame when an auto-transformer is used. (see Figure III in Appendix A
to subpart J of this part)
(3) Each three-phase output circuit of the generator must be
equipped with a sensitive ground fault relay. The protective relay must
be set to cause the circuit interrupting device that supplies power to
the primary windings of each transformer to trip and shut down the
diesel engine when a phase-to-frame fault of not more than 90
milliamperes occurs.
(4) Each three-phase output circuit that supplies power to
equipment must be equipped with an instantaneous sensitive ground-fault
relay that will cause its respective circuit interrupting device(s) to
trip and cause shutdown of the diesel engine when a phase-to-frame
fault occurs. The grounded-phase protection must be set at not more
than 90 milliamps. Current transformers used for the ground-fault
protection must be single window-type and must be installed to encircle
all three phase conductors. Equipment safety grounding conductors must
not pass through or be connected in series with ground-fault current
transformers.
(5) Each three-phase circuit interrupting device must be provided
with a means to provide short-circuit, overcurrent, grounded-phase,
undervoltage, and ground wire monitoring protection. The instantaneous
only trip unit for the circuit interrupting device(s) in use must be
adjusted to trip at not more than 75 percent of the minimum available
short circuit current at the
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point where the portable cable enters the equipment or the maximum
allowable instantaneous settings specified in Sec. 75.601-1, whichever
is less.
(6) The equipment portable cable length(s) must not exceed the
length(s) specified in 30 CFR part 18, appendix I, table 9,
Specifications for Cables Longer than 500 Feet.
(7) Permanent label(s) listing the maximum circuit interrupting
device setting(s) and maximum portable cable length(s) must be
installed on each instantaneous trip unit or be maintained near each
three-phase circuit interrupting device. The permanent label(s) must be
maintained legibly.
(8) The circuit interrupting device that supplies three-phase power
circuit(s) to the equipment being powered must be limited to the use of
only one circuit interrupting device at a time when equipment is being
moved in, out, and around the mine.
(9) The grounding system must include an MSHA-accepted ground wire
monitor system that satisfies the requirements of Sec. 75.902; or have
a No. 1/0 or larger external grounding conductor to bond and ground the
frames of all equipment to the f