British Columbia Mine Reclamation Symposium

Selenium concentration and loading in the vicinity of Bullmoose mine during post-closure phase Liu, Wenying; Baldwin, Susan A.

Abstract

Selenium release from mine waste materials triggers significant environmental and social problems. This article reports results of a case study of concentrations and loads of selenium in the vicinity of the closed Bullmoose coal mine located in northeastern British Columbia. To illustrate what has been happening in the post-closure phase, we analyzed historical data on total selenium concentrations at the discharge point (SP-2) and in the receiving stream over an eight-year period after the mine was closed. It was found that selenium concentrations in the receiving Bullmoose Creek exceeded the current water quality guideline of 2 μg/L. The highest selenium loads were discharged at SP-2 in June (65%). A linear regression analysis showed a slight downward trend in June selenium loads discharged. Correspondingly, the stream received the highest proportion of selenium in June, and June stream selenium loads also showed a slight downward trend. Dilution was thought to be the major factor in dictating stream selenium concentration in the high-flow period. Even though the stream received minimal loads of selenium in September, consistent monitoring on stream selenium concentrations in this low-flow period was important due to low dilution and possible selenium desorption via hyporheic exchange.

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Attribution-NonCommercial-NoDerivatives 4.0 International