Selenium Concentrations in Mine Refuse and Mist Mountain Rocks; Evaluation of Variations Laterally and Over Time

The distribution of Selenium (Se) in the Jurassic-Cretaceous Mist Mountain Formation of southeastern British Columbia was documented in a previous study by Ryan and Dittrick (2001). As part of that study, complete sections of rock types, including coal seams were sampled, as well as various materials segregated by mining such as coarse refuse and solid tailings from tailings ponds. Preliminary results indicate that coal seams of the Mist Mountain Formation have Selenium concentrations similar to the world average for coal seams. The interburden rocks of the Mist Mountain Formation generally contain more Se than expected based on their composition but this is a function of their association with coal seams, which concentrate Se above the crustal average value. Selenium concentrations, within the Mist Mountain Formation, were higher in rocks with higher clay content and those closely associated with coal seams such as hanging wall, footwall and in-seam splits.