Laserfiche WebLink
For a 100 foot length of the 400 foot armoring stretch, we <br />will not build up the existing dike. Rather the dike will <br />simply be armored on the river side and the pit side. This <br />depression will direct the rising flood waters of the river <br />into the pit in a controlled fashion. <br />2. The dike between Cells A and B will have a 1.5 foot <br />depression in it to direct flood flows from Cell A to Cell <br />B. Waste concrete will be cut into the top of the dike to <br />serve as a cutoff wall and prevent erosion of the dike at <br />this point. <br />3. Flood waters will exit Cell B down river by simply <br />overflowing at the north end of Cell B. There will be no <br />raised berm or levy here and the waters can simply spread <br />out at a low velocity and flow down the floodplain. <br />Groundwater <br />The proposed mining will intercept alluvial groundwater from the <br />Valley Fill Aquifer along the South Platte River. Depth to the <br />groundwater varies from 0 to 8 feet below the surface. The <br />impacts from the mining operation will mainly occur during <br />dewatering operations. There will be some drawdown on the <br />aquifer in the immediate vicinity. Well owners could see some <br />reduc;tion in their water table. <br />Accompanying this exhibit is a list and map of nearby wells. <br />Many of these wells are shallow and have a junior appropriation. <br />Due 'to the dewatering operation, we do expect the groundwater in <br />the immediate vicinity of the mine to drop. In order to mitigate <br />these: impacts on nearby wells, the applicant has proposed the <br />following measures. <br />1. The most significant mitigation measure is the sealing of <br />the side slopes to prevent groundwater infiltration. As <br />stated earlier, the final land use of the mine is as a water <br />storage reservoir. In order to accomplish this, the side <br />slopes will be sealed with a clay liner to prevent any <br />leakage of groundwater. This clay liner will be installed <br />as the mining progresses each year. Each year the mining <br />will involve from 6 to 10 acres. We estimate this will <br />generate from 800 to 1,500 linear feet of shore line to seal <br />with clay. Thus, only a small part of the pit sides will be <br />allowing groundwater seepage. <br />G-2 <br />