Oregon Administrative Rules
Chapter 340 - DEPARTMENT OF ENVIRONMENTAL QUALITY
Division 43 - CHEMICAL MINING
Section 340-043-0150 - Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Guidelines for Heap-Leach and Tailings Disposal Facility Closure
Current through Register Vol. 63, No. 3, March 1, 2024
(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:
(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.]
To view tables referenced in rule text, click here to view rule.
Statutory/Other Authority: ORS 468.020
Statutes/Other Implemented: ORS 468.020 & 517.770