The mistakes of the past, which result in the unfortunate legacy issues people know from historic mining areas, reflect the past lack of knowledge and understanding of the long-term impacts on water of various discharges. A great many of today’s standard practices were not available to our predecessors; they simply didn’t have the scientific research results nor technology now available to us. This lack of knowledge and foresight also resulted in insufficient bonding amounts. Many legacy issues in Montana are related to open pit mines with much larger volumes of rock, huge waste piles and unlined tailings disposal facilities located directly in waterways. At Black Butte Copper, we have looked at every legacy issue that has occurred and initiated a solution to make sure that our environment is protected so that those issues cannot happen here.
Proactive initiatives include:
- In order to keep water from leaving the mine and mixing with creek water, all planned openings or entry points to the mine (including air ventilation and escape routes) are located far above the water table and the tunnel entry location was specifically chosen because it is almost 200 feet above the water level. Water cannot run uphill out of the mine so nothing can ever drain/flow out of the mine. This ensures that legacy accidents cannot happen again.
- All ground water from the mine and surface water from precipitation will be collected, monitored, tested, and treated before being placed back into the ground water system through an underground infiltration system buried 6-8 ft. below the surface. There is zero discharge to surface waters.
- A reverse osmosis (RO) water treatment plant will be constructed on-site for the duration of the mining operation and will remain there for as long as it’s needed.
Additionally, the Johnny Lee deposit is completely encased by rocks having a high concentration of carbonate, which acts as a buffering (or neutralizing) agent against acid. In our intensive test work, these minerals have successfully neutralized the acidity that has been produced by sulfide oxidation. Sandfire is taking every measure to minimize acid production, and the large volumes of carbonate in the mined rock and its host rocks are expected to be a great help in managing potentially acid generating rock (PAG). Mine operations around the world developed in carbonate host rocks are very successful in protecting the environment.
Sandfire takes protecting all the water resources incredibly seriously. Montana law requires that in order to secure a MOP, neither water QUALITY nor QUANTITY can be degraded.