Cost-Saving Water Management Strategies for the Control of Runoff from Mine Developments

Abstract

Sediment-laden runoff from mining activities in British Columbia is potentially detrimental to fish and wildlife populations in nearby streams and rivers. B.C. Ministry of Environment Guidelines require the construction of ditches to collect contaminated runoff from mine areas and waste dumps. The collector ditches connect to sedimentation ponds which settle out suspended solids before discharge to a natural stream. The guidelines recommend a return period for peak flows on collector ditches of 1 in 200 years.The construction of a drainage and sedimentation pond system to protect downstream water courses can result in significant capital costs for a new mine. Several design strategies have been developed which reduce capital costs while still providing environmental protection. The application of these methods to the Teck Bullmoose Coal Mine in Northeast British Columbia is illustrated.Water management strategies used at the Teck Bullmoose Mine have included designing a flow-through rock drain to avoid a costly stream diversion around a waste dump, modifying standard roughing pond design to eliminate an additional spillway and incorporating competent rockfill material in flood protection dykes to reduce riprap costs.