OAR 340-043-0130
Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Guidelines for Disposal of Mill Tailings

(1)

Mill tailings shall be treated by cyanide removal, reuse, or destruction prior to disposal to reduce the amount of cyanide introduced into the tailings pond to the lowest practicable level. The permittee shall conduct laboratory column tests on mill tailings to determine the lowest practicable concentration to which the WAD cyanide (weak-acid dissociable cyanide as measured by ASTM Method D2036-82 C) can be reduced. In no event, shall the permitted WAD cyanide concentration in the liquid fraction of the tailings be greater than 30 ppm.

(2)

The permittee shall determine the potential for acid-water formation from the tailings by means of acid-base accounting and other suitable laboratory static and dynamic tests. If acid formation can occur, basic materials shall be added to the tailings in the amount of three (3) times the acid formation potential or to give a net neutralization potential of at least 20 tons of CaCO3 per 1,000 tons of tailings, whichever is greater, before placing tailings in the disposal facility.

(3)

The disposal facility shall be lined with a composite double liner consisting of a flexible-membrane synthetic top liner in tight contact with an engineered, stable, soil/clay bottom liner (maximum coefficient of permeability of 10-7 cm/sec) having a minimum thickness of 36 inches. Construction of the liner shall generally follow the principles and practices contained in EPA/600⁄2-88⁄052, Lining of Waste Containment and Other Impoundment Facilities, September, 1988.

(4)

The disposal facility shall be provided with a leachate collection system above the liner suitable for monitoring, collecting and treating potential acid drainage.
[Publications: Publications referenced are available from the agency.]

Source: Rule 340-043-0130 — Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Guidelines for Disposal of Mill Tailings, https://secure.­sos.­state.­or.­us/oard/view.­action?ruleNumber=340-043-0130.

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 340-043-0130’s source at or​.us