OAR 340-043-0150
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Guidelines for Heap-Leach and Tailings Disposal Facility Closure


(1)

The waste disposal facilities shall be closed under these rules in conjunction with the reclamation requirements of DOGAMI (Oregon Department of Geology and Mineral Industries).

(2)

An updated closure plan and post-closure monitoring and maintenance plan shall be submitted to the Department by the permittee at least 180 days prior to beginning closure operations or making any substantial changes to the operation. The closure plan must be compatible with DOGAMI’s reclamation plan and may be part of it.

(3)

Chemical conveyances (ditches, troughs, pipes, etc.) not necessary for post-closure monitoring shall be removed. The secondary containment systems shall be checked before closure for process-chemical contamination, and contaminated soil or other materials, if any, shall be removed to an acceptable disposal facility.

(4)

Closure of the heap-leach facility:

(a)

The heap shall be detoxified over a suitable period of time prior to closure, using rinse/rest cycles of rinsing and chemical oxidation, if necessary. The WAD cyanide concentration in the rinsate shall be no greater than 0.2 ppm;

(b)

Following detoxification as defined in subsection (a) of this section, the heap shall be closed in place on the pad by covering the heap with a cover designed to prevent water and air infiltration. The cover should consist, at a minimum, of a low-permeability layer and suitable drainage and soil layers to prevent erosion and damage by animals and to sustain vegetation growth, in accordance with DOGAMI’s reclamation rules;

(c)

The ponds associated with the heap shall be closed by folding in the synthetic liners and filling and contouring the pits with inert material. Residual sludge may be disposed of in one of the on-site waste disposal facilities, provided it meets the criteria for such wastes in these guidelines. The process chemical collection system of the heap shall be maintained in operative condition so that it can be used to monitor the amount and quality of infiltrated water, if any, draining from the heap.

(5)

The tailings disposal facility shall be closed by covering with a composite cover designed to prevent water and air infiltration and be environmentally stable for an indefinite period of time. Maximum effort shall be made to isolate the tailings from the environment. Construction of the cover shall generally follow the principles and practices contained in EPA/530-SW-89-047. Technical Guidance Document — Final Covers on Hazardous Waste Landfills and Surface Impoundments.
[NOTE: View a PDF of EPA Guidance Document by clicking on “Tables” link below.]
[ED. NOTE: To view attachments referenced in rule text, click here to view rule.]

Source: Rule 340-043-0150 — Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Guidelines for Heap-Leach and Tailings Disposal Facility Closure, https://secure.­sos.­state.­or.­us/oard/view.­action?ruleNumber=340-043-0150.

340‑043‑0000
Purpose and Policies
340‑043‑0010
Definitions
340‑043‑0020
Permit Required
340‑043‑0025
Permit Conditions on Assumption of Liability
340‑043‑0030
Permit Application
340‑043‑0040
Plan and Specifications
340‑043‑0050
Design, Construction, Operation and Closure Requirements
340‑043‑0060
Exemption from State Permit for Hazardous Waste Treatment or Disposal Facilities
340‑043‑0070
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Purpose
340‑043‑0080
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: General Provisions
340‑043‑0090
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Control of Surface Water Run-On and Run-Off
340‑043‑0100
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Physical Stability of Retaining Structures and Emplaced Mine Materials
340‑043‑0110
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Protection of Wildlife
340‑043‑0120
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Guidelines for Design, Construction, and Operation of Heap-Leach Facilities
340‑043‑0130
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Guidelines for Disposal of Mill Tailings
340‑043‑0140
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Guidelines for Disposal or Storage of Wasterock, Low-Grade Ore and Other Mined Materials
340‑043‑0150
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Guidelines for Heap-Leach and Tailings Disposal Facility Closure
340‑043‑0160
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Post-Closure Monitoring
340‑043‑0170
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Land Disposal of Wastewater
340‑043‑0180
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Guidelines for Open-Pit Closure
Last Updated

Jun. 8, 2021

Rule 340-043-0150’s source at or​.us