We are keen to improve all aspects of our community including opportunities for recreationists and tourists. We are looking to our stakeholder group for recommendations of positive measures we can support as we develop this project.
Category Water & The Environment
Yes, we are looking forward to working with our conservation community to enhance the fisheries. This is an important area for cut throat restoration and we believe there are opportunities for us to assist in these important efforts. We have established a “stakeholders” group to listen to concerns of the conservation community and to get their input on conservation enhancements.
The estimated average base flow in Sheep Creek at the project is 15 cfs and at its confluence with the Smith River is 30 cfs during low flow periods of November through March. The average base flow in the Smith River during this period is approximately 90-100 cfs. Sheep Creek provides approximately 10% of the flow passing by the project and 30% of the flow in the Smith River at their confluence.
All of the water not consumed by the milling process at the mine will go through the reverse osmosis (RO) water treatment plant and then be returned immediately back to the groundwater system through an underground infiltration system. The consumptive use rate of the mine is 210 gpm; resulting in any additional water pumped being returned directly to the groundwater system (210-290 gpm).
Estimated dewatering rates pumped from the mine range from 220 gpm to 500 gpm as the mine access is developed. The dewatering rate during full operation is estimated between 420 and 470 gpm. All but the 210 gpm of water needed for use in the milling process returns back to the groundwater system via the underground infiltration system after treatment by the reverse osmosis water treatment system.
Our numeric hydrologic model shows that any water table changes affect only the area of the mine itself with noticeable drawdown only in the part of the bedrock hydrologic system containing the mine. Continuously backfilling the mine with cemented tailings reduces the extent of drawdown as mining advances. The water table will return to normal on completion of mining.
Sandfire has designed the BBCP to completely protect Sheep Creek and its fisheries, and in turn the Smith River and all the recreational uses and businesses supported by it. The operation will treat all water released from site to meet Montana’s strict non-degradation standards and return the treated water straight back into the ground water system through an underground infiltration system buried 6-8 feet in highly permeable ground.
Yes, the mining process will use nitrates as underground in explosives. The environmental will be protected by the reverse osmosis water treatment process which will ensure we are able to meet the non-degradation discharge standards set by the Montana Department of Environmental Quality by removing nitrates from the water.
Sandfire has designed the Black Butte Copper Project for quick reclamation at the end of mine life with no need to treat water in perpetuity on site. We have chosen a cemented tailings facility (CTF) because it offers the highest environmental protection and quickest reclamation of any tailings facility designs we studied. Because the CTF will have no pond of standing water during operations, once the mine closes Sandfire will cover the facility with a 100 mil HDPE liner, weld it to the lower double liner, and cover the liner with 4 or more feet of fill, top soil, and grass. The pump will remain in the CTF to treat and test the small amount of water that may seep until the facility stabilizes and monitoring will continue as long as required by the DEQ.