Montana Resources is part of a modern generation of mine operators. We strive to innovate processes and utilize more efficient technologies that lessen the impact of mining on the environment.
Water Quality
Water is a necessary part of the Montana Resources mine operation. A pulverized rock slurry emerging from the concentrator and thickener tanks is pumped to the Yankee Doodle Tailings Pond where the flour-sized byproduct of the mill process settles out before the water is piped back to the mine operation or to the Polishing Facility for a final treatment step prior to off-site discharge. Copper is also extracted from the water pumped from the nearby Berkeley Pit, as well as other site waters, in precipitation cells. These waters then go through water treatment processes for metals removal, incorporation into the site water balance, and if needed, off-site discharge.
Berkeley Pit Water Treatment Process
Air Quality
Mining is about rock and machines and is bound to raise dust, for which every effort is made to minimize. As needed, 52,000-gallon capacity water trucks wet down all haul roads. Montana Resources has 240- and 250- ton capacity haul trucks. The large trucks move more ore per trip, using less fuel per ton than previous 170-ton haul trucks, thus creating less overall dust and diesel emissions.
In dry weather, water trucks constantly wet down haul roads in never-ending circuits.
Non-Ore Rock
Once non-ore rock is identified, it is hauled to either a rock disposal site or used in the tailings storage facility construction. All of Montana Resources’ rock disposal sites are designed to prevent generation of acid mine drainage. Any waste rock determined to contain high-sulfide materials with capability of creating acidic compounds is encapsulated inside the repository to be capped, contoured and revegetated.
Non-ore rock is the first layer, followed by pH-neutral alluvium. (For example, the reclamation plan specifies slopes less than 5% to receive 28 inches of pH-neutral cover soil with the top 6 inches being topsoil or cover soil amended to contain 1.5% organic material by weight.) The recontoured area is then seeded with a site-specific recipe of native grasses approved by the Montana Department of Environmental Quality including wheatgrass, bluegrass, fescue and wildrye.
Reclamation
Commonly, an open pit mine is active for the entire life of the pit, only reclaimed when it becomes dormant. Montana Resources practices concurrent reclamation, reclaiming as soon as possible while mining operations continue. Soil is saved and stockpile whenever it is available. Completed rock disposal sites undergo surface shaping, being recontoured to prescribed slopes in a layer thickness determined by the slope profile. The result creates grassy rolling hills inhabited by deer and other wildlife. Montana Resources also maintains an active noxious weed control program on mine property.