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Exhibit D - Minin.¢ Plan <br />3. Afrer the WSF design has been approved by the State Engineer, the WSF will be deepened to <br />achieve final design depth and for reclaiming the Expansion Area North as shown in <br />Reclamation Plan B. A Technical Revision describing this plan and bonding changes will be <br />submitted before the WSF is deepened. <br />4. Expansion Area Soutlt will be mined afrer Expansion Area North. Before this area is mined, a <br />Technical Revision will be submitted to include associated operational, hydrologic, and <br />bonding changes to this permit. <br />Should a liner be constructed to isolate the WSF from ground water, the liner will be designed <br />and constructed per the guidelines of the Colorado Department of Natural Resources, Division of <br />Minerals and Geology Guide to Specification Preparation For Slurry Walls and Clay Liners as a <br />Component of A Colorado Mined Land Reclamation Permit, September 2000. The liner <br />construction will be approved by the State Engineer's Office. All permanent pit lake <br />embankments will be graded to a maximum 3H:1V slope with a top elevation to match <br />surrounding topography. Because the liner will ensure minimal infiltration of ground water, the <br />impacts to local ground water wells will be negligible. <br />Pit Lakes 1 and 2 will be dewatered prior to additional extraction of sand and gravel and <br />construction of the liner. Dewatering is allowed under the existing permit, but we have chosen to <br />limit dewatering during the summer months. Dewatering operations would occur for <br />approximately six months or until slopes for the liner are built. When the liner is completed, <br />minimal affects to the local ground water wells will occur and dewatering of the WSF will begin. <br />Afrer approval by the State Engineer's Office that the WSF has been properly constructed, the <br />WSF will be deepened to finish reclamation of the Worthing Pit and Expansion Area Nortlt. <br />Much of the material removed to deepen the WSF will be gravel, inert shale and clay. <br />Existing Pit Lake 3 at the Worthing Pit has been reclaimed as a pond and is currently used for <br />fishing. Pit Lake 3 will not be disturbed by the proposed operations. <br />Should a liner be constructed to isolate the WSF from groundwater, there will be minimal <br />infiltration of groundwater. if this is done, there will be no reason to limit dewatering during <br />summer months, so dewatering may take place year round If all of both Pit Lakes 1 and 2 are <br />converted to a WSF, there will be no groundwater exposed to evaporation. Should the WSF not <br />use all of Pit Lakes 1 and 2, no more than the pre-1981 total surface area of 28 acres will be left <br />exposed to evaporation at closure of the amended permit area (Worthing Pit and the Expansion <br />Areas) without an approved water augmentation plan. <br />Expansion Area North <br />Mining in Expansion Area North will be conducted from north to south using the typical box cut <br />technique consistent with open pit sand and grave] mining activities. Because of the small size of <br />the operation, the total 21 acres of disturbance will occur in the first year. Working pit slopes will <br />be nearly vertical (O.SH:1 V). A haul road will extend into the pit as mining progresses from north <br />to south. It will be maintained at a slope of no greater than 10 percent with side wall slopes no <br />greater than 2H:1 V. <br />1898-Frei 112 Exhibits_(4.20.05).doc D-3 <br />