A pilot project to treat more up to 26.5 million L/d (7 million gal/day) from the Berkley Pit in Butte, MT is on track to begin five years ahead of schedule.
The Montana Standard reported that Montana Resources has begun laying the groundwork at the mine site for the impending pilot project to begin.
Montana Resources has been busy fusing and laying down pipe around the mine. The pipe will carry the initial 11.3 Million L/d (3 million gal), later to become 26.5 million L/d (7 million gal/day) of water each day through a complex system of treatment and usage before any water makes its way down to Silver Bow Creek.
Montana Resources is waiting on six custom-built pumps that are due to arrive this fall. Two pumps will go into the pump house near the pit’s edge. The other four will be close to the Horseshoe Bend Water Treatment Plant.
Mark Thompson, Montana Resource's vice president of environmental affairs said two years ago that the companies spent $1 million upgrading Horseshoe Bend Water Treatment Plant, which plays a crucial role in the process.
A polishing plant has yet to be built. That will be the final step the water will go through before it hits the creek.
A mini plant that was set up as a mini-version of Horseshoe Bend Water Treatment Plant to test the water and apply different scenarios.
Once the Berkeley Pit water begins pumping and treatment, that should prevent significant sloughing, Thompson said.
The last major sloughing event took place in February 2013. Roughly 800 kt (850,000 st) of sediment fell into the pit. As a result, the water rose .6 feet, according to Pitwatch.org.
Once the treatment begins, the pit water will twist around the mine in a complex system. A pump house will pump the water out of the pit and send it to the precipitation plant, which will recover the copper out of the water. The water will then travel to Horseshoe Bend Water Treatment Plant, where it will go through treatment, before it is routed through the mine workings.
From the mill, the water will then head to Yankee Doodle Tailings Pond, where copper and molybdenum are removed. The water settles out to the north side of the pond.
Another pipe will route water at the back of the pond, which is relatively clean water, back down the hill to the polishing plant.
The Berkeley Pit is a former large open pit copper mine that was in operation from 1955 to 1982, when Atlantic Richfield ceased operations and shut off the industrial-sized groundwater pumps. The pit generates acid and the water in it is loaded with a cornucopia of heavy metals.
The treated discharge water is expected to add 10 cubic feet per second of flow to the creek. Montana Fish, Wildlife and Parks Fish Biologist Jason Lindstrom said recently that the added water to the stream can impact the creek in a variety of ways.
“I’m mostly worried about temperature,” Lindstrom said.
“It’s a deep reservoir, 100 feet deep. It’s kind of like the water coming out of other reservoirs, which are typically cooler than a small stream,” he said.