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feed line extends from the metering pumps in the Electrical Control Building to the east cell of the <br />impoundment, near the outlet of the borehole pump discharge line. An aerator has been placed downstream <br />of the inlet into the pond so that the sodium hydroxide is dispersed throughout the cell, promoting the <br />precipitation of iron from the mine discharge water. <br />The water flow through the cells was modified to take advantage of additional retention time in the system. <br />The original flow path focused on using hvo of the three cells at any one time. Presently, all three cells are <br />used and this required installation of a new inter-pond line behveen the center and western cell. The baffles <br />in the cells reduces the potential for short-circuiting, increasing the efficiency of the pond. The final <br />component added to the system was placement of an aerator in the western cell. This aerator may be turned <br />off after the one in the eastern cell is turned on. <br />Due to the fact that the pH is being elevated, it was decided to have sulfuric acid available in the event a pH <br />adjustment was needed prior to the efFluent discharging from the system. The chemical and equipment for <br />[his procedure is house in the chemical storage building located on the west side of the west cell as shown on <br />Map 32. This system will be used only if the efFluent approaches the pH discharge limitation of 9.0. <br />Eastern Mining District - Dewaterin2 Borehole <br />The dewatering system will be divided into hvo components: 1 j dewatering borehole and control building, <br />and 2) treatment facility. The dewatering borehole will be constructed above and into the sump developed <br />off of the 10 Right entry. Please refer to Map 23, Mine Plan, for the proposed location of the sump. Alight <br />duty road will be constructed into the site beginning at the treatment facility and terminating at the borehole. <br />The beginning 1,600 feet of this road will require new construction while the remainder of the road will see <br />the upgrading of an existing ranch road. The location of the access road is shown on Maps 17 and 18. As is <br />shown on the maps, the overall length is approximately 4,600 feet. This proposed road location differs <br />• slightly from the original proposal in order to allow for an entrance that has greater visibility, thus increasing <br />the safety for those using the road. The beginning 1,600 feet of the access and light dup~ road is the segment <br />that differs from the original proposal. <br />During construction of the road, approximately 6,815 CY of topsoil will be windrowed to the side of the <br />road. This volume is based on constructing a road 4,600 feet long, 20 feet wide and salvaging topsoil to a <br />depth of 24 inches. The topsoil will be stockpiled adjacent to or windrowed to the side of the road. The <br />stockpiled topsoil will be seeded with the pastureland seed mixture applied at the appropriate rate. The <br />finished width of the road will be approximately 12 feet and it will be covered with approximately 9 to 12 <br />inches of 6" pit run and 3 to 4 inches of 11/2" road base or crushed rock. It is planned to install culverts <br />along [he road. For definition purposes, the beginning 700 feet is an access road and the remaining 3,900 <br />feet is a light-duty road. The design calculation for these culverts, numbered EMD-1 through EMD-4, is <br />presented in Exhibit 8a, Culvert Sizing -EMD Dewatering Facility Access Road. <br />• <br />APP1tOVEID APR 1 4 2000 <br />TR 00-35 2.05-77.1 03/28/00 <br />