Information Center


Information Type FAQs

How big will the Black Butte Copper Project be underground?

Mining of the Johnny Lee deposit requires only a small underground operation by modern standards. The upper zone is 3,000 feet long in a north south direction, and 1500 feet wide in an east west direction. The Johnny Lee lower zone lies 1500 feet below the bottom of the Sheep Creek Valley, and gently rises to a depth of 1100 feet on its western end. The lower zone is 3,000 feet long in an east west direction. The surface opening (portal) for the 5,000 foot long access tunnel for the Johnny Lee deposit will lay on the south side of Sawmill Hill, well outside the Sheep Creek Valley and is 200 feet above the water table. This deposit hosts just under one billion pounds of high grade copper.

What other minerals might be mined?

Besides copper, the Johnny Lee deposit hosts important quantities of both cobalt and silver. Further metallurgical testing will determine whether we can recover these economically. There is a small amount of gold in the Johnny Lee lower zone, but not enough to be economically viable.

Are there any fault zones near the deposit?

Although there are active fault zones in Montana, the fault closest to the deposit called the Volcano Valley Fault is dormant.  This is a major fault zone passing between the upper and lower zones of the Johnny Lee deposit. Current geologic interpretations indicate that this fault is long dormant (80 million years) and poses no threat to the mining operation or environment.

What is the “Johnny Lee” deposit?

The Johnny Lee deposit at Black Butte is named for a homesteader/prospector who lived above the deposit in the early 1900s. The mineral deposit includes two sheet-like zones rich in extremely high grade copper-iron-sulfide (chalcopyrite). It is the second highest grade copper deposit currently under permit in the world. In fact, it is more than 10 times higher than in most modern surface mines.

Are there things we can do to enhance the fisheries?

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.

How much water does Sheep Creek supply to the Smith River?

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.

What happens to the water once it is pumped out of the mine workings?

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).

How much water will be pump from the mine?

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.

Will our “cone of depression” extend to the Sheep Creek alluvium?

The cone of depression over the mine area extends slightly into the Sheep Creek alluvium with the largest drawdown near the western and southwestern edge of the alluvium. The drawdown in the alluvium adjacent to Sheep Creek is one foot. This indicates that the drawdown in the alluvium has the potential to slightly deplete flows in Sheep Creek. The numerical model shows that the potential maximum depletion in Sheep Creek is approximately 0.45 cfs (~200 gpm). The base flow (lowest yearly flow) of Sheep Creek is 6700 gpm, so our maximum effect on Sheep Creek could be 3% of its flow. We will be replacing more than this with our mitigation plan.

Read More