2014-10-06_INSPECTION - M1985029

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Report on discharge of suspended clay from Alma Placer Mine RECFIuED James R. Murray, Managing Partner, High Mountain Mining Co., LLC O('.T 06 ?_014 October 5, 2014 DIVISION OF RECLAMATION MINING AND SAFETY Background High Mountain Mining Co., LLC (HMMC) is the owner operator of the Alma Placer Mine which is fully permitted gold placer mine and gravel operation adjacent to the town of Alma, Co. The Middle Fork of the South Platte River is located on the western edge of the mining property. The mine utilizes water taken from the river at its designated diversion point via a turbine pump located in a pump house adjacent to the mine entrance road at the river. The mine process uses gravity concentration to segregate and wash the placer material consisting of sand, gravel, and clay/silt thus separating the gold from the material and leaving sand and gravel as a saleable byproduct. No chemicals or reagents are used in the mining and processing operation, although the mining permit allows use of a flocculent to settle solids and current plans call for reinstituting its use. The water used to accomplish the gravity concentration and gravel washing is recycled and reused via 4 settling ponds with Pond 1 receiving most of the fine sand from the plant not captured in the sand recovery system. The discharge from Pond 1 flows to Pond 2 where finer suspended solids settle. The discharge from Pond 2 then flows to Pond 3 and then to Pond 4 where it is pumped back to the process plant. During normal operation, the water quality in Pond 4 is clarified but somewhat murky with most of the still suspended solids being clay with a particle size smaller than 200 mesh. Makeup water and fresh water used in the process is pumped from the river either directly to the process plant or to Pond 4. The sediment from Ponds 1 and 2 are periodically mechanically cleaned out via track mounted backhoe excavators with the solids being either stockpiled or directly applied in lieu of topsoil on mined areas being reclaimed. Ponds 3 and 4 however are too large and the solids content too low to allow mechanical removal of the sediments from the banks of the ponds via conventional earth moving equipment. As a result, Ponds 3 and 4 are full of clay sediment and HMMC has acquired a floating dredge to remove the sediments. All of the necessary components have been acquired within the last few days and this work will commence during the next few days. Recent Events On Friday, Oct 3, an employee of Jerry Miller, contract miner for HMMC, notified Jerry at approximately 8:00 a.m. that the stream below the Alma Placer Mine appeared to be cloudy and carrying suspended solids. Jerry arrived on sight shortly after that, verified 1