Idaho Administrative Code › Title IDAPA 58 - Environmental Quality, Department of › Rule 58.01.13 - RULES FOR ORE PROCESSING BY CYANIDATION › Section 58.01.13.200 - REQUIREMENTS FOR WATER QUALITY PROTECTION

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)