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REVETT MINERALS 3- to 6-in. on each pass until the lift reaches 10 ft. The impoundment is divid- ed into four cells. "One of the biggest issues we have with the tailings impoundment is tails blowing off the lifts in dry summer season," Miller said. "We use various means to control the dust." Water pumped from the mine is fed by gravity to a set of sprinklers that irrigate and reduce the dust. The impoundment is not lined. In- stead, Miller refers to it as a huge sand fil- ter. Lake Creek, which sits 300 to 400 ft away is one of the premier Bull Trout ecosystems. "We have never had any impact on that ecosystem," Miller said. With each 10-ft lift, the mine places 6- to 8-in. topsoil (growth media) on the tailings and seeds it. Wheat and barley are planted in the inactive cells. "Every couple of lifts, we plant some trees," Miller said. "We now have trees in excess of 20 ft tall. At final closure, this tailings facility would become a wildlife habitat." Water sampling above and below the impoundment and at many locations around the mine show healthy amounts of macro-invertebrates or in fly fisherman speak, stoneflies and mayflies. "They are more sensitive than the fish and we have had no issues in 25 years of sampling," Miller said. The Rock Creek Project The Rock Creek ore body was discovered by Bear Creek Mining (Kennecott) in the early 1960s, and was later optioned to Asarco. As with Troy, Rock Creek was held 75% by Asarco and 25% by Kennecott. In addition to the Rock Creek claims, Revett also acquired some contiguous claims which were held 100% by Kennecott. Asarco explored the property from 1974 through 1983, expanding on the work pre- viously started in 1966 by Kennecott. The permitting process commenced in 1987 when a plan of operations was sub- mitted to the U.S. Forest Service (USFS) and the Montana Department of Environmental Quality (DEQ). The Rock Creek deposit is situated on USFS land, specifically within the Kootenai National Forest, and under the Cabinet Mountain Wilderness Area, and as such required fed- eral, as well as state approvals to develop. The project, as proposed, is to be developed in two phases: (1) the con- struction and development of the Evaluation Adit and (2) the development of the mine and construction of the mill facilities. Revett recently won an appeal in the 9th Circuit on a ruling on its 2003 Record of Decision (RoD) and, with a few more permitting approvals and a revised RoD in hand, it will be in a position to construct the Evaluation Adit. The evalu- ation program will take 18 to 24 months to complete. Assuming the company can complete a positive feasibility study, gain the necessary construction permits and find the project financing, Revett intends to develop Rock Creek as a 10,000 tpd, room-and-pillar mine similar to Troy with conventional crushing and grinding of the ore followed by bulk sulphide flota- tion, producing a copper/silver-based concentrate that would be shipped to a smelter by rail. The Evaluation Adit will serve several functions, Miller explained. "There would be a 3,000-ft decline to get to the ore body," Miller said. "Then miners would drive a 4,000-ft drift through the ore body with additional exploratory drill sites, proving up the resources. In addi- tion to the exploratory drilling, a lot of 70 E&MJ; • JUNE 2012 www.e-mj.com