2011-08-11_REVISION - M1977256 - Laserfiche WebLink

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EXHIBIT D MINING PLAN (carer) disturbed areas. When topsoil or growth medium is encountered on newly stripped area, it will be stored on the setback areas or the mine floor for use in reclamation. If the stockpiles remain undisturbed for more than a year the piles will be seeded with 3# PLS of Western Wheatgrass per 200 square feet to prevent erosion. The growth medium piles will be kept within 500 feet of the seedbed to reduce the haul distance where it will be needed during reclamation. As mining progresses thru the site and additional stripping is done the material will either be stock- piled for later use or moved directly to the areas needing resoiling. We expect to continue to mine into the working face now located in the central part of the existing permit area. The Mining Plan Map shows how this looks when approximately 20% of the area has been mined. The estimated direction of mining is shown as a series of arrows on the Mining Plan Map. The slopes will be created as mining progresses around the mine perimeter according to this revised sloping plan. Cur- rently, the exterior sloping plan requires that the exterior slopes be graded 3:1. This was established in the reclamation recommendations presented in the Soil Conservation Service and shown on the Reclamation Plan Map. In all of our mines we use 2:1 slopes to maximize gravel extraction so we are changing the approved sloping plan so the slopes around the exterior of the mine will be no greater than 2:1. On the slopes along the Powerline ROW they will be no- steeper than 3:1. Review of the Pre - Mining Map show the slopes, where mining is complete, are graded approximately 2:1. If Options #2 and #3 are exercised there will be no slopes left in those areas. In the new area we will have 2:1 slopes on the east and south sides, so more flat area will be created. We realize the 2:1 slopes are harder to revegetate but the increased gravel obtained from them and the larger flat area will offset the additional reclamation costs. When the mine is active the working face is worked as near vertical as possible. When mining ends during a season the face is graded to 2:1 or less so it is stable. Please see MAP EXHIBIT C -1 for how the area may look as mining progresses through it. As much as possible, the surface drainage will be maintained in the same direction as it now exists. We have not had a problem with surface water entering or leaving the existing site since mining began in 1977. We do not expect this to be a problem and the proposed sloping plan for the excavated area should eliminate any concerns of erosion occurring on the site. We have not experienced any unusual dust control problems on the site to date. One can only estimate the amount of water needed for dust control at this time, but since there is no water on the site we will be hauling it into the site from a source approved for that use. Most of the water used for dust control will be used on haul roads. In a typical year we use 3 to 5 ac- ft per year. Please refer to EXHIBIT G -WATER (1996) for the discus- sion of how water will be used at the site. 5 (revised 8 -8 -11)