Current through August 31, 2023
The following design and performance standards are intended as
the minimum criteria for protection of public health and waters. These
standards apply to all facilities unless the Department determines that other
site-specific criteria, including an alternative design approved under Section
205, are appropriate to protect
water quality and the public health. (3-24-22)
01.
Professional Engineer. Plans
and specifications for construction, alteration or expansion of any cyanidation
facility must be prepared by or under the supervision of an Idaho licensed
professional engineer and bear the imprint of the engineer's seal. Construction
must be observed by an Idaho licensed professional engineer or a person under
the supervision of an Idaho licensed professional engineer. (3-24-22)
02.
Plans and Specifications.
Final plans and specifications for the construction of a cyanidation facility
must be submitted to and approved by the Department before construction may
begin. All construction must be in compliance with the plans and specifications
approved by the Department. Within thirty (30) days of the completion of such
construction, modification or expansion, complete and accurate plans and
specifications depicting that actual construction, modification or expansion
does not deviate from the original approved plans and specifications must be
submitted to the Department. (3-24-22)
03.
Manufacturer's
Specifications. Manufacturer's specifications for materials and
equipment necessary to meet the requirements of Subsection
100.03.r. and Sections
200 through
205 for containment of process
water must be submitted to the Department with the plans and specifications
required in Subsection
200.02 before construction may
begin. (3-24-22)
04.
Siting
and Preparation. All cyanidation facilities including, but not limited
to, the process building, laboratories, process chemical storage and
containment facilities, plumbing fixtures that support process water, untreated
or treated process water ponds, tailings impoundments, ore stock piles, and
spent ore disposal areas must be appropriately sited and prepared for
construction. Siting criteria must ensure that, at a minimum, the facilities
are structurally sound and that containment systems can be adequately protected
against factors such as wild fires, floods, land slides, storm water run-on,
erosion, migrating stream channels, high ground water table, equipment
operation, subsidence of underground workings, public access and public
activities. All sites must be properly prepared prior to construction of
foundations and facilities. Vegetation, roots, brush, large woody debris and
other deleterious materials, top soil, historic foundations and plumbing, or
other materials that may adversely affect appropriate construction and long
term stability, must be removed from the footprint of the cyanidation facility
unless approved by the Department. (3-24-22)
05.
Process Water Storage Sizing
Criteria. All aspects of the cyanidation facility that entrain, utilize,
treat, discharge, pump, convey, or otherwise contain process water, treated
process water, or run-off water from any portion of the cyanidation facility
must be included in the water balance. Each pond, tailings impoundment, and
ditch containing process water must be designed to maintain a minimum two (2)
foot freeboard during storage or conveyance of the design climatic events plus
maximum expected normal operating levels. Leach pad design must provide
containment of the maximum expected operating flows plus storm flows from the
design climatic event. At a minimum, a cyanidation facility must be designed to
contain the maximum expected normal operating water balance and the volume of
run-on and run-off water associated with a climatic event that has a one
percent (1%) annual exceedance probability. Snowmelt events will be considered
in determining the maximum flow volume during the design climatic event.
Contingency plans for managing excesses of all water included as a part of the
water balance must be described in the water management strategy. Each
structure that impounds process water or process-contaminated water must
include a means of passing excess water unless otherwise approved by the
Department. (3-24-22)
06.
Minimum Plans and Specifications. Unless the Department approves
an alternative design under Section
205, the plans and specifications
for any portion of a cyanidation facility that will contain process water must
satisfy the applicable general design criteria in Subsection
200.06 and the design criteria
in Sections 201 through
204 for the type of facility
receiving process water. These provisions establish minimum pollutant control
technologies and define the site and operating conditions that must be
evaluated. (3-24-22)
a. Cyanidation facility
design must: (3-24-22)
i. Minimize releases of
pollutants into ground water or subsurface migration pathways so that any
release will not cause unauthorized degradation of waters. (3-24-22)
ii. Preclude any differential movement or
shifting of the subgrade, soil layer, liner or contained material that
endangers containment integrity as a result of the proposed range of operating
conditions for each component and anticipated seismic activity at the site.
(3-24-22)
iii. Include additional
containment of process water, as requested by the Department, in areas where
ground water is considered to be near the surface. Ground water is considered
to be near the surface if: (3-24-22)
(1) The
depth from the surface to ground water is less than one hundred (100) feet and
the top one hundred (100) feet of the existing formation has a hydraulic
conductivity greater than 10-5 cm/sec;
(3-24-22)
(2) Open fractured or
faulted geologic conditions exist in the bedrock from the surface to the ground
water; or (3-24-22)
(3) There is an
inability to document that all borings beneath the cyanidation facility have
been adequately abandoned. (3-24-22)
iv. Not locate new process component
containing process water within one thousand (1,000) feet of any dwelling that
is occupied at least part of the year and not owned by the permittee. This does
not apply to modifications at a facility that predates such a dwelling.
(3-24-22)
v. Include measures for
preventing wildlife contact with process water having a WAD cyanide
concentration in liquid fraction exceeding fifty (50) mg/L. The Department may
require additional measures if wildlife mortality is observed.
(3-24-22)
vi. Implement measures to
protect birds, other wildlife and livestock from adverse effects of cyanide
process water and other pollutants. (3-24-22)
vii. Include a quality assurance/quality
control plan for the construction of containment systems that provides a
process for documenting owner acceptance of all underlying components of the
containment system prior to construction of the overlying components.
(3-24-22)
b. Liner
systems must: (3-24-22)
i. Have a structurally
stable subgrade for the overlying components and contained material. The
subgrade should be constructed to resist consolidation, excessive differential
settlement that compromises liner performance, and uplift resulting from
pressures inside or outside the containment unit to prevent distortion of
overlying components. (3-24-22)
ii.
Have a smooth rolled and compacted soil layer, or equivalent layer approved by
the Department, in intimate contact with the overlying geomembrane liner with
the following characteristics: (3-24-22)
(1) A
minimum thickness of twenty-four (24) inches compacted to ninety-five percent
(95%) of maximum dry density according to Standard Proctor Test ASTM D698 or
Modified Proctor Test ASTM D1557; (3-24-22)
(2) Soil placed in a minimum of four (4)
lifts that each have a compacted thickness of six (6) inches and a hydraulic
conductivity less than or equal to 10-6 cm/sec;
(3-24-22)
(3) An uppermost lift of
soil that does not contain particles in excess of point seven five (0.75)
inches (nineteen (19) mm) in largest dimension unless larger particles are
consistent with the manufacturer's specifications for the overlying liner and
approved by the Department; (3-24-22)
(4) No putrescible, frozen, or other
deleterious materials. (3-24-22)
(5) No angular, sharp material regardless of
diameter; and (3-24-22)
(6) Soil
placed within two percent (2%) of optimum moisture content to achieve the
specified compaction and hydraulic conductivity. (3-24-22)
iii. Include the following if an equivalent
layer replacing the soil layer described in Subsection
200.06.b.ii. is proposed:
(3-24-22)
(1) A layer that is not a
geomembrane and has a liquid flow rate no greater than that of twenty-four (24)
inches of compact soil with a hydraulic conductivity less than or equal to
10-6 cm/sec; (3-24-22)
(2) Materials with appropriate chemical
properties and sufficient strength and thickness to prevent failure due to
pressure gradients (including static head and external hydrogeologic forces),
physical contact with the waste, process water, or process-contaminated water
to which they are exposed, climatic conditions, the stress of installation, and
the stress of daily operation; (3-24-22)
(3) Materials that provide appropriate shear
resistance of the upper and lower component interface to prevent sliding of the
upper component including on slopes; (3-24-22)
(4) Certification from an Idaho licensed
professional engineer that the liquid flow rate per unit area through the
equivalent layer is no greater than the liquid flow rate through two (2) feet
of compacted soil with a hydraulic conductivity less than or equal to
10-6 cm/sec, considering the maximum hydraulic head
anticipated on the liner system and the thickness of the equivalent layer
replacing the two (2) feet of compacted soil; and (3-24-22)
(5) Plans and specifications for an
equivalent layer that substantially reflect the manufacturer's specifications
and standards for construction, operation and maintenance unless otherwise
approved by the Department. (3-24-22)
iv. Include geomembrane liners consisting of
high density polyethylene, linear low-density polyethylene, or equivalent,
rated as having a resistance to the passage of process water equal to or less
than a hydraulic conductivity of 10-11 cm/sec. Each
geomembrane liner will be constructed of materials with appropriate chemical
properties and sufficient strength and thickness to prevent failure due to
pressure gradients (including static head and external hydrogeologic forces),
physical contact with the waste or leachate to which they are exposed, climatic
conditions, the stress of installation, and the stress of daily operation and
permanent closure. (3-24-22)
v. Be
constructed according to manufacturer's standards, or Department-approved
design standards, and protect against damage from cracking, sun exposure, ice,
frost penetration or heaving, wildlife, wildfires, and damage that may be
caused by personnel or equipment operating in or around these facilities.
(3-24-22)
vi. Have an appropriate
coefficient of friction against sliding plus a factor of safety for each
interface constructed on a slope. (3-24-22)
vii. Have minimum factors of safety, and the
logic behind their selection, for the stability of the earthworks and the
lining systems. (3-24-22)
viii.
Include redundant systems for failures in primary power or pumping systems.
(3-24-22)
ix. Have liner material
that meets the manufacturer's quality assurance/quality control performance
specifications. (3-24-22)
07.
Process Buildings, Process Chemical
Storage Containment Areas and General Facility Criteria. Storage,
handling and use of all process chemicals, process wastes, process water and
pollutants associated with the cyanidation facility must be conducted within a
clean, safe and secure work space to prevent unauthorized discharges to soils,
ground water or surface water. The plans and specifications must contain
sufficient detail, including pump capacity and plumbing for evacuation of
collection sumps, triggering systems for sump evacuation, and monitoring and
reporting requirements and, where appropriate, provide for: (3-24-22)
a. Structural integrity of the foundation,
walls and roof for process and process chemical storage buildings;
(3-24-22)
b. Restriction of public
access; (3-24-22)
c. Protection of
wildlife; (3-24-22)
d. Internal
sumps and spill cleanup plans; (3-24-22)
e. Grouted and sealed concrete stemmed walls
and floors in the process buildings and process chemical storage and
containment facilities; (3-24-22)
f. Vapor barriers and frost protection;
(3-24-22)
g. Segregation of process
chemicals according to compatibility; (3-24-22)
h. Communication systems; (3-24-22)
i. Fire suppression systems, internal and
external; and (3-24-22)
j. Quality
assurance/quality control for construction activities and construction
materials. (3-24-22)
08.
Cap and Cover Criteria. Caps and covers used as source control
measures for facilities must be designed and constructed to minimize the
interaction of meteoric waters, surface waters, and ground waters with wastes
containing pollutants that are likely to be mobilized and discharged to waters.
Caps and covers designed for permanent closure must demonstrate permanence
applicable to the permittee's designed and approved permanent closure plan.
(3-24-22)
09.
Plumbing and
Conveyance Criteria. Plumbing and conveyance systems must: (3-24-22)
a. Be structurally sound and chemically
compatible with the materials being conveyed; (3-24-22)
b. Provide adequate primary and secondary
containment; and (3-24-22)
c. Be
protected against heat, cold, mechanical failures, impacts, fires, and other
factors that may cause breakage and result in unauthorized discharges.
(3-24-22)
10.
Operation and Maintenance Plans. Operation and maintenance plans
must be submitted to the Department for review and approval. Operation and
maintenance plans must include, but are not limited to: (3-24-22)
a. An overall plan that includes techniques
for evaluating the integrity and performance of all containment systems;
(3-24-22)
b. Schedule for
inspections of all containment systems; (3-24-22)
c. Schedule for inspections on piping and
conveyance systems that carry process water; (3-24-22)
d. Response plans that detail specific
actions that will result in mitigation of compromised or damaged containment
systems; and (3-24-22)
e. Response
plans that detail specific thresholds identified under Subsection
200.11, the locations and
frequency at which the thresholds will be monitored, and actions that will
result in mitigation of an exceedance of any threshold.
(3-24-22)
11.
Water
Quality Monitoring and Reporting. The water quality monitoring plan
submitted with the application must be reviewed and, if appropriate, approved
by the Department. The approved water quality monitoring plan must: (3-24-22)
a. Provide for physical, chemical and
biological monitoring, including measurements of surface water flow, wildlife
and bird mortality, and aquatic indicator species in potentially affected
surface and ground water, as appropriate; (3-24-22)
b. Provide for sampling locations and
frequency; (3-24-22)
c. Provide an
assessment of the existing surface and ground water conditions prior to
construction of the proposed cyanidation facility; (3-24-22)
d. Be site specific and dependent on
location, design and operation of the cyanidation facilities included in the
overall operating plan; (3-24-22)
e. Specify compliance points and associated
water quality compliance criteria; (3-24-22)
f. Specify monitoring points and threshold
concentrations that provide for early detection of discharges of pollutants;
(3-24-22)
g. Provide analytical
methods and method detection limits for chemical analysis used in the
determination of water quality; (3-24-22)
h. Provide a quality assurance quality
control plan for data collection and analysis; (3-24-22)
i. Provide for appropriate and timely
analytical data analyses including evaluations of water quality and quantity
trends; (3-24-22)
j. Provide an
annual environmental monitoring and data analysis report of water quality and
quantity trends; (3-24-22)
k.
Provide for the reporting and re-sampling of monitoring locations where
detectable and statistically significant changes in water quality are found.
The permittee must propose a statistical method to determine the significance
of the changes in water quality; and (3-24-22)
l. Provide for anticipated changes or
modifications to monitoring plans, which may be the result of a phased approach
to cyanidation facility construction, operations and permanent closure.
(3-24-22)
12.
Monitoring Wells Siting and Construction Plans. The applicant is
encouraged to submit a report describing the purpose, objectives, location and
proposed construction of monitoring wells to the Department for review and
comment during the initial stages of site characterization. A monitoring well
siting and construction plan must be provided upon submittal of the preliminary
design report under Subsection
050.02. (3-24-22)
a. Monitoring well siting and construction
plans must provide for the following. (3-24-22)
i. A quality assurance/quality control plan
for well construction. (3-24-22)
ii. A minimum of three (3) monitoring wells
with one (1) located up gradient and two (2) located down gradient of primary
components of the cyanidation facility to determine ground water flow
direction. (3-24-22)
b.
Siting and planning for additional wells or replacement wells may be required
in the permit application and final permit. Specifically, additional wells may
be required for: (3-24-22)
i. Large areas with
multiple potential sources for pollutants; (3-24-22)
ii. Areas with complex geology, fractured
bedrock; and (3-24-22)
iii. Areas
with insufficient background hydrogeology. (3-24-22)
c. All monitoring well construction must also
conform to the well construction rules listed in IDAPA 37.03.09, "Well
Construction Standards Rules." (3-24-22)
d. Record diagrams including well
construction details, well elevation and a detailed geologic log must be
provided to the Department for each monitoring well.
(3-24-22)
13.
Land
Application. Plans and specifications must include: (3-24-22)
a. An operation and maintenance plan
including: (3-24-22)
i. Water balance for the
land application site; (3-24-22)
ii. Pretreatment requirements and procedures;
(3-24-22)
iii. Operating season for
land application; (3-24-22)
iv.
Seasonal closeout procedures; (3-24-22)
v. Special soils or vegetative amendments;
(3-24-22)
vi. Storm water
run-on/run-off controls; (3-24-22)
vii. Best management practices for all areas
impacted by the land application system; and (3-24-22)
viii. A topographic map of the land
application site and adjacent affected areas, of sufficient scale to facilitate
site-specific analysis of soils, vegetation, surface water, and ground water;
(3-24-22)
b. Chemical,
physical, and volumetric characteristics of the material to be land applied;
(3-24-22)
c. A complete description
of the chemical and physical characteristics of the soils and applicable
geology of the land application site; (3-24-22)
d. Methods of process water treatment,
distribution and disposal; (3-24-22)
e. Hydraulic loading capacity of the soils;
(3-24-22)
f. Constituent loading
capacity of the site; (3-24-22)
g.
Attenuation capacity of the vegetative covers and soils; (3-24-22)
h. Evapotranspiration capacity of the site;
(3-24-22)
i. Testing and analytical
procedures for water quality and soils samples prior to, during, and following
the land application process; (3-24-22)
j. Trend analysis of the constituent loading
in the affected soils, vegetation, and water quality of the affected surface or
ground water systems; (3-24-22)
k.
Reporting requirements including both frequency and form; and
(3-24-22)
l. Standby power and
pumps sufficient to maintain all treatment and distribution works.
(3-24-22)
14.
Temporary or Seasonal Closure. Temporary and seasonal closure
plans for the entire cyanidation facility must be submitted by an applicant to
the Department for review and approval prior to issuance of a final permit.
Temporary and seasonal closure plans may, subject to Department approval
pursuant to Section 750, be
modified to provide for changes in operating conditions of the facilities and
must incorporate a water management plan for the period of inactivity as well
as during shut down and reactivation. (3-24-22)
a. Prior to seasonal closure, process
buildings, process chemical storage, process water ponds, tailings
impoundments, spent ore disposal areas and other ancillary facilities must be
stabilized and/or conditioned to prevent any emergency or unauthorized
discharges to surface or ground water. (3-24-22)
b. Subsequent to seasonal closure, process
buildings, process chemical storage, process water ponds, tailings
impoundments, spent ore disposal areas and other ancillary facilities must be
maintained to prevent any emergency or unauthorized discharges to surface or
ground water. Cyanidation facilities must be conditioned and maintained to
provide: (3-24-22)
i. Material stabilization
for all solids affected by process waters; (3-24-22)
ii. Optimum freeboard in all ponds, as
dictated by the water management plan; (3-24-22)
iii. Fully functional power and pumping
systems that are ready for use; both power and pumps are to incorporate
redundant systems to allow for failure of either power or a pumping system. A
failed power supply or pump is not an acceptable reason for an unauthorized
discharge; (3-24-22)
iv. Protection
of all containment; and (3-24-22)
v. Sufficient availability of qualified staff
to restrict public access, fully implement the water quality monitoring plan,
and initiate the emergency and spill response plan.
(3-24-22)
15.
Employee Education Program. Operators and staff of facilities must
be properly oriented and trained to operate, maintain, and protect containment
systems; waste disposal and discharge systems; and to implement monitoring and
emergency and spill response plans. An applicant must submit an employee
orientation and continuing training plan to the Department for review prior to
issuance of a final permit. The plan must provide the format and contents for
training, the general qualifications of the person(s) responsible for training
and testing, and the person(s) or positions who must receive such training.
(3-24-22)
