| Summary: | In 1991, Environment Canada and the British Columbia (B.C.) Acid Mine Drainage Task Force
initiated a project with the goal of compiling information for closed and abandoned mine sites
throughout British Columbia. The ultimate objective of the study is to assess the current and
potential impacts caused by acid rock drainage (ARD) on surface water quality throughout the
province. In addition, in the Fraser River basin, non-mining sources of ARD (such as natural
weathering, railway and road cuts and municipal developments) are also being considered. This
paper presents the results of the evaluation with respect to the regional distribution of closed and
abandoned mines throughout B.C. and the regional ARD potential based on a derived ranking
scheme.
Three regions of the province were identified as having a high potential for ARD. There are
several acid-producing mines in the Smithers and Stewart regions and Vancouver Island, and
other mines are in geological settings which could allow ARD to be produced. The Kootenay
region has seen extensive historical mining activity, but there is a lack of environmental data for
individual mines. The presence of limestone and calcite in the mine sequences limits ARD
potential in the Kootenays, although this mineral is not always closely associated with ore
minerals.
In general, the Fraser River basin has less historical mining activity than the rest of B.C, partly
as a result of glacial drift cover. The potential for ARD in the basin also appears lower than
elsewhere due to the common occurrence of calcite-bearing volcanic rocks.
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