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Date:  November 4, 2008
Contact:  Greg Albright (406) 896-5260 or
                David Williams (406) 533-7655

Proposed Mine Expansion Approved

The Montana Department of Environmental Quality and the Bureau of Land Management have issued Records of Decision approving the proposed M Pit Expansion at the Montana Tunnels Mine near Jefferson City. 

The agencies evaluated three alternatives and selected one that provides for improved reclamation and a more natural modification for Clancy Creek around the north side of the expanded pit.  The proposed mine expansion would extend operations for about five years beyond the current operating plan. An estimated 24 to 28 million additional tons of ore would be removed.

Under the proposed expansion, Montana Tunnels would increase the permitted pit disturbance area, deepen the mine pit, expand waste rock disposal areas, raise the tailings storage facility embankment, realign a segment of the Jefferson County mine access road, divert two stream channels, and construct new soil stockpiles. Clancy Creek would be diverted around the expanded pit during operations using a combination of a pipe and an open-flow channel. 

Upon cessation of mining, the M-Pit would be reclaimed as a pit lake, as is allowed under the existing reclamation plan, with steep highwalls above the water level. Clancy Creek adjacent to the mine pit would flow in a constructed channel. No water from Clancy Creek would be diverted into the pit. Additional storm water would be routed to the mine pit to help form the pit lake. The pit lake would reach equilibrium about two centuries after mining ceases at elevation 5,625 feet, or about 25 feet below the elevation of Clancy Creek, and would not have a surface discharge.

The Record of Decision is available at both the DEQ website at www.deq.mt.gov and the BLM Website at http://www.blm.gov/mt/st/en/fo/butte_field_office.html.

Questions can be referred to Dave Williams or Joan Gabelman at (406) 533- 7600.



Last updated: 06-28-2012