British Columbia Mine Reclamation Symposium

Post closure mine dewatering and treatment of contaminated waters at the Sullivan Mine in Kimberley, B.C. Tarasoff, Dan; Ramdin, Zoe

Abstract

The Sullivan Mine has been operated by Cominco Ltd. since 1909, and is scheduled for closure in December of 2001. The Sullivan ore body is acid generating but operated for many decades before the need to control acid rock drainage (ARD) was recognized. Presently, the generation of ARD can not be prevented, only mitigated. The main sources of ARD include drainage from the underground mine workings, run off and seepage from mining and milling wastes and discharges from the operating tailing ponds. The generation of ARD is expected to continue for an indefinite period after closure. While several projects have been undertaken to minimize the generation of ARD in the last 20 years of mine and concentrator operation, a plan to deal with the on-going generation of these contaminated waters after closure was required. Components of the existing ARD mitigation system will continue to function with some modifications to account for the reduction in ARD volumes generated due to reclamation efforts and the cessation of mining and milling operations. The Drainage Water Treatment Plant (DWTP), which utilizes lime to increase pH and remove metals from ARD into a high-density chemically stable sludge, is the key to current and long-term treatment of contaminated waters. Collection and storage of ARD prior to treatment at the DWTP is another important aspect of ARD control. The DWTP cannot operate continually at design capacity with the expected reductions in post closure ARD flows. For post closure operation, safe storage of contaminated waters is required until the volumes will allow the treatment plant to operate at design levels for a reasonable period of time. A two-reservoir system utilizing the under-ground mine and a surface pond has been designed for contaminated water storage. Three deep-well underground pump stations will be located within the mine. The mine will be allowed to fill to a predetermined level, after which, mine water will be pumped to the above-ground ARD reservoir and subsequently to the DWTP for treatment and discharge to the St Mary River. The DWTP will operate on a campaign basis during periods when the impact on the receiving water, the St Mary River, is minimized.

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