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bedrock at the deepest. As seen on Map C-3, the sediment pond will then discharge into the <br />north fork of the Gunnison River. An NPDES discharge permit will be acquired for this <br />operation. Since the existing groundwater level is so close to bedrock, the pit pump will not <br />always be below the mining level. When the pump is at bedrock, it will be surrounded by a 30 <br />foot wide gravel berm to clean the water prior to pumping. The discharge will be via a 10 inch <br />diameter HDPE pipe for a distance of 225 feet into the river. The pipeline discharge will have 24 <br />inch to 36 inch boulders in place as armoring along the river embankment. <br />2. Ranch Dike Repair <br />In 2004, the north fork of the Gunnison River breached the Ranch dike along the north side of <br />mining phase 1. Engineering consultants Crane & Associates designed a new dike structure that <br />was then installed on the northeastern section of the dike. As part of the technical revision, Tri <br />County Gravel will complete the repair of the Ranch dike to the specifications laid out in the <br />Crane & Associates design. The dike design can be seen in Appendix B - Dike Design. <br />After the initial breach of the dike in 2004, Tri County Gravel replaced the upper portion of the <br />dike with compacted overburden and boulders. The dike at this end is currently approximately <br />130' wide across the top with 3H:1 V slopes along both sides. The river side slope is armored <br />with boulders. <br />The remainder of the dike, as seen on Map C-3, will be a minimum of 120' wide across the top, <br />with 3H:1 V minimum slopes. The river side slope of the dike will be armored with boulders. <br />Also, the gully along the northeastern edge of the dike that flows into the pit will be armored <br />with large rocks. Since phase 1 is already excavated, the remaining 3H:1 V slopes will be <br />constructed entirely of fill. Some overburden for the dike is already available in a approximately <br />3000-5000 cubic yard pile located on the western side of phase 1, just south of the current dike <br />opening. As mining progresses, available overburden will be added to the dike until it is <br />complete. The dike slopes at the upstream end will be watered to encourage vegetation growth <br />for added slope stability. <br />Tri County Technical Revision Sept 07 4