Work is continuing following sloughing and seepage issues at the tailings pond on the old HB Mine site near the Village of Salmo. The tailings pond is owned by the Regional District of Central Kootenay as part of their central landfill area.
Heavy rainfall, particularly Tuesday, and inflow from creeks and streams caused sloughing and ongoing seepage to the dam structure and road surface. The problems were identified as part of a regular monthly inspection of the dam.
An improvement in weather conditions and the installation of additional high capacity pumps to draw down the pond has reduced the pressure and lowered the water level considerably in the past 24 hours. Siphoning hoses and other equipment is also being sent from the East Kootenay and Alberta to assist with reducing the pressure on the dam.
Environmental monitoring and sampling is taking place daily at three on-site locations: at the top end of the tailings pond, at the top of the spillway and downstream at the culvert crossing Highway 3 and 6.
The surface water being pumped and flowing down the spillway and a natural drainage area on the other side of the dam is relatively clean. There is some cloudiness from sediment and turbidity caused by erosion and sloughing from the dam itself. The tailings are particulate and ordinarily do not dissolve, although minute amounts could be suspended particulate as a result of lowering the water levels. Pumps have been strategically placed to ensure there is no disturbance of tailings.
All water being pumped is flowing downstream in the channels as intended. The two flow streams join and enter a culvert at the highway and then into a drainage ditch before entering the Salmo River. There have been no impacts on the few residents in the immediate area.
Engineers on site from the RDCK and assisting agencies will develop a longer term remediation plan once the pond has been lowered to a more manageable level. This will involve examining piping and other refinements made to the tailings pond and dam over the years. Once the exact sources of seepages are identified and the structure is determined safe for heavy equipment and operators, in-filling, shoring and rock replacement will begin.
The HB mine site tailings pond is located approximately 0.5 kilometres east of the Crowsnest Highway (3 & 6). It is about 7 kilometres south of the Village of Salmo in the West Kootenay Selkirk Mountain range. The tailings pond has a surface area of approximately 6 hectares.