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Hydrogeological assessment for mitigation of groundwater discharge to a creek in a confined valley : part 1 of 2 case study from the former Sullivan mine, Kimberley, BC

British Columbia Mine Reclamation Symposium; University of British Columbia. Norman B. Keevil Institute of Mining Engineering

The former Sullivan Mine, one of the world's largest producers of lead, zinc and silver, officially closed in 2001 after 92 years of active production. Two large waste rock dumps exist in the incised Mark Creek valley, in what is called the Lower Mine Yard. This area underwent remediation in the 1990s, with an engineered and vegetated cover, isolation of the stream from the rock dump seepage and partial collection of seepage for treatment. Investigations and monitoring of groundwater and surface water in the Lower Mine Yard have been occurring since the early 1990s. Two aquifers were identified, one a shallow perched aquifer and the second a deep aquifer that is constrained in the valley by a low permeability basal till. Both aquifers have been affected by acid rock drainage and metal leaching from the adjacent waste rock dumps, with vertical groundwater flow from the shallow aquifer affecting the deep aquifer. A hydraulic interception system was installed in the deep aquifer to collect and transmit affected groundwater to Teck’s drainage water treatment plant. In 2012, seepage thought to be from the shallow aquifer was identified in two locations on the south bank of Mark Creek and temporary mitigation measures were implemented to recover affected water. Between 2012 and 2015, intensive investigations took place to understand the cause of the discharges. The investigations showed that the hydrogeology of the shallow aquifer is complex, and the discharges are related to two different types of perching. The first is a classically perched groundwater unit overlying a lower permeability silt unit, but there no clear mechanism could be identified for the second perched unit. These two types of perching, combined with the interplay of influences from low-elevation snowmelt in March/April and freshet in May/June, required intensive monitoring of groundwater and surface water. Results from the investigations were used to provide a basis for assessment of remedial options and subsequent design of an interception trench to improve the capture of shallow groundwater in this area and to further mitigate the potential for discharge to Mark Creek.

Conference Paper

eng

Vancouver : University of British Columbia Library

10.14288/1.0391936

Non UBC

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