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To: DRMS Den Page 5 of 6 2018-04-25 20:42:34 (GMT) 13032008630 From. Ben Langenfeld <br />Gold veins in igneous rock on the south side of Hoosier Pass and in the upper basin of the South <br />Platte drainage are the origin of the Park County placers through thousands of years of glacial <br />activity during the last ice age and subsequent erosion. Due to the fineness of gold at the site <br />(0.833 line), the gold placer has been traced to bold from North Star Mountain in the <br />Montgomery Deadwood area in the upper reach of the basin. <br />Past mining history shows sigi- ficant gold placer deposits are found in dips or depressions in the <br />bedrock within the permit area. Good concentrations can also be found in previous locations of <br />the South Platte River channel, Seismic testing (2002) of the exact bedrock location shows <br />sporadic dips and an older channel location near the west edge of the permit area. Based on <br />seismic test results and past operations, this horizon will be targeted for placer mining. Seismic <br />cross section locations are shown on Map G3. Cross sections showing the bedrock to gravel <br />contact as well as the current surface are given on Map C-3. <br />Topsoil, overburden, and separated waste fines will be stockpiled and used to backfill the slopes <br />of mined out areas to a 311A V slope during Reclamation us shown on Map P -l. 1t is expected <br />that 15 to 25 feet of overburden gravel will be excavated and placed in previous pit excavations <br />to access the lower 5-15 feet of gravel above bedrock that is known to contain high gold <br />concentrations. In unmined areas, topsoil will be salvaged and stockpiled as shown on Map C-2. <br />The expected average depth of topsoil is 4.5" based on existing cuts in the pen -nit area. To <br />prevent erasion of topsoil and overburden stockpiles, piles will be seeded within 180 days of <br />establishment with the rangeland seed mix or quick oats. Stockpiles will be constructed to <br />2.511.1 V slopes for topsoil and overburden. <br />Gold placer mining will occur in cuts of approximately 300 feet long by 150 feet wide with <br />214.1 V side slopes to access bedrock at an average maximum depth of 30 feet. Cuts will be <br />completed within lettered mining areas shown on Map G-2 with a general mining direction from <br />the northwest to the southeast. Mining in each area includes: topsoil and overburden stripping, <br />placer gold mining, and backfilling. <br />Prior to any mining for this amendment, a berm with a minimum 8 foot height, 211:1V side <br />slopes will be created along the Highway 9 ROW (right of way) for at least 600 feet around the <br />active mining area. This will visually shield the operation from the Ilighway/Main Street, as well <br />Alma Placer Mine XC tqg U..ck and A, -v!iir : J 9 <br />December 2017 D-2 <br />