Laserfiche WebLink
Each mining cut is approximately 300' long x 150' wide. Overburden will average approximately 20' <br />depth while the gold bearing gravel will average approximately 7.5' depth. Therefore, the overburden <br />to remove for each cut is 300'x150'x20' = 33,333 cy. The gold gravel is 300'xl50'x7.5' = 12,500 cy. <br />Since approximately 15% of the gravel is greater than 5" size, 85% or 10,625 cy will be sent to the <br />plant for each cut. Therefore, the plant operation for each cut will take approximately 11 days. Due <br />to other operations such as topsoil removal and replacement, overburden removal and regrading, <br />pump setup and other items, it is assumed that each cut will take approximately 45 days or 1.5 <br />months. Therefore, approximately 10,625 cy of gold bearing gravel will be processed in the plant <br />every 45 days which is equivalent to 43,000 cy per year. This is equivalent to 64,000 tons per year. <br />This amount less 6% for fines loss, is the amount available for the gravel operation per year = 60,000 <br />tons per year. This amount may increase if the overburden amount is less, or if plant efficiency <br />increases. <br />Cut 1 has no topsoil, therefore, its overburden will be moved northeast to the previously disturbed <br />area and regraded. The original Pond A has been excavated to remove silt buildup and has been re- <br />stored to its original size and volume. The new excavation was split into 2 ponds now called Pond 3 <br />and Pond 4, as shown on Map C -2. These ponds are exactly where Pond A was located. After Cut 2, <br />a dewatering pump will be placed at the bottom of the cut to deliver water to Pond 4. The operation <br />will then shift to the area immediately south of the existing access road in Cuts 3, 4 and 5. The <br />dewatering pump in these cuts will also deliver the water to the new Pond 4. All subsequent cuts will <br />deliver water to the South Ponds #3 and #4 at the south end of the permit area. These ponds are dif- <br />ferent from the ponds that settle the discharge water from the plant. <br />At any one time, three cuts will be active. The one in advance of the active cut will be stripped of <br />topsoil and will also have overburden removal activity. The active pit will have overburden removal <br />and gold bearing gravel mining. The cut behind the active pit will have overburden placement, re- <br />grading and topsoil placement. Reclamation plan details are described in Exhibit E. <br />Alma Placer Mine 1115 16 <br />