Laserfiche WebLink
~II IIIIII'll"I"II <br />RECEIVED <br />MINING PLAN MAY 0 8 ~ggg EXHIBIT D (coop <br />Division of MinerdIS 8 Geology <br />Using this sediment delivery ratio and the other parameters described above, the calculations for the <br />RUSLE are as shown below for the initial 10 year operation: <br />Sits 8 ~ 1.,~ ~ ~ SDL Tons/Ac Acres Tons/vr <br />Initial 10 Yrs 10 .36 .83 .90 1.0 .SO ].34 29.20 39.26 <br />The 3 year sediment erosion is therefore 39.26 tons x 3 = 117.8 tons. <br />Using a typical sediment density of 85 lb/cubic ft., this results in a 3 year sediment volume of .064 <br />acre-feet. The total volume of the pond is the 100 year storm inflow volume + three year sediment <br />erosion volume. This volume is 1.55 ac-ft + 0.064 ac-ft = 1.61 ac-ft. <br />The pond will be excavated at the lowest pout of the pit azea, as shown on Figure 4. The pond will <br />be approximately 100 ft wide x 500 ft long and will have a minimum depth of 2.0 feet, resulting in <br />a volume of 2.30 ac-ft. The pond dimensions may change due to constant excavation in the pit, <br />however, the volume required (l.61 ac-ft), will always be maintained If some unexpected sediment <br />delivery to the pond occurs, it will be cleaned out to maintain the required volume. <br />The only portions of the disturbed area which will not drain to the sediment pond are the lower <br />reaches of the access road. For this area, which is no greater than 0.2 acres in size, hay bales will <br />be placed along the access road ditch and a small sump of approximately 30 cubic yards will be <br />constructed at the bottom of both sides of the access road to further contain sediment. This sump <br />will be cleaned periodically to maintain its sediment trapping efficiency. <br />30 <br />