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Chapter IV <br /> Sediment ponds were designed and constructed to according to the requirements of <br /> • 4.05.6 (8). <br /> All sediment ponds will be examined quarterly by the company for the following: <br /> — Seepage from the downside side of the embankment, <br /> especially around the discharge pipe. <br /> — Erosion of embankment slopes. <br /> — Obstructions to emergency and/or principal spillways. <br /> — Properly cleaned and maintained dewatering devices. <br /> — Sediment storage volume. <br /> — Sloughing, tension cracks, piping, etc. <br /> The quarterly inspection reports will be submitted to the regulatory authority. <br /> Sedimentation ponds will be removed after disturbed areas have been restored and <br /> revegetated, following mine closure, in accordance with the post-mine reclamation plan. <br /> Each pond will be removed, unless approved for retention as part of the post mining <br /> land use, and the area disturbed by the pond will be regraded, topsoiled and <br /> revegetated. <br /> Reclamation of sedimentation ponds will be accomplished following mine <br /> abandonment, although ponds approved for retention in support of the post mine land <br /> use plan will remain. They will be removed after the disturbed areas have been <br /> . restored and revegetated in accordance with.the post mine reclamation plan. The <br /> reclamation of the ponds will be accomplished when the drainages meet applicable <br /> water quality standards. When the sedimentation pond is removed, the disturbed area <br /> will be regraded, topsoiled and revegetated. <br /> Secondary sedimentation control structures have been utilized, in accordance with <br /> 4.05.5, using the best technology currently available. Dugout ponds were constructed <br /> to control erosion by reducing overland flow velocity and runoff volume, and to trap <br /> sediment from several disturbed areas. These ponds were constructed in conformance <br /> with the U.S. Soil Conservation Service Practice Standard 3784 for "Ponds" (October, <br /> 1978). The design consists of an embankment less than 3 feet above the original <br /> ground. Table IV-C-1 indicates the B.A.T. ponds. <br /> 7. Discharge Standards. <br /> The sedimentation ponds have been designed to provide a minimum sediment storage <br /> of 0.1 acre feet of sediment per acre of disturbed land, or designed to contain the 3 <br /> year sediment storage from the disturbed area using the Universal Soil Loss Equation <br /> (USLE). The designed retention time of the ponds is 24 hours, with dewatering devices <br /> of either a valve activated or T-culvert discharge system or unlined impoundment <br /> ._natural filtration. <br /> 20 <br />