Stillwater Mining gets go-ahead for new tunnel
18 September 2015USA - The US Forest Service and Montana Department of Environmental Quality signed off on September 1 on construction of the Benbow Exploration Portal and Support facilities for Stillwater Mining Co. (SMC), at Custer National Forest, near Dean, Montana.
The Benbow Exploration Portal is part of SMC's Blitz project at the Stillwater Mine. A TBM will be used to mine an approximately 20ft (6m) diameter tunnel for exploring ground and rock characterization, and evaluating mine feasibility. Following the drive, if feasible the approximately 23,000ft tunnel will be used long-term for underground ventilation, secondary underground egress, and limited mine resupply.
Under existing approved operations, SMC is currently developing underground mine workings from the Stillwater Mine (i.e. west to east) using a refurbished 5.5m-diameter main beam TBM from The Robbins Company, which had previously been used on New York's East Side Access project. SMC's intent is to drive mine workings approximately 25,000ft to the eastern extent of the J-M Reef. As of June the TBM has progressed 7,800ft. The Benbow tunnel will be developed from the north and would eventually link into these mine workings.
SMC operates two underground mines along the J-M Reef, the world's richest known deposit of platinum group metals, located in the Beartooth Mountains in south-central Montana.
