2009-01-08_INSPECTION - M1988048

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We will establish a stormwater detention "pond" on the eastern boundary of the amendment area; because during and after mining, the amendment area will be slightly lower than the Phase 1 area to its east. The majority of the time, there will not be water in the "pond," but in the case of a storm event, the "pond" will be of an adequate size to hold any excess water from sheet run-off. Stormwater detention ponds should be able to hold 900 cubic feet of water per acre. We are mining 83 acres, so the pond will be constructed to hold at least 74,700 cubic feet. The pond will not be lined, to allow for percolation of stormwater into the soil. We will maintain the pond after mining is completed. We have a similar detention pond on the currently permitted area, which is part of our Stormwater Management Plan, and which has worked well for detaining water in the rare storm events. From our experience in this area, we have found that the surface topsoil and overburden are very permeable. Our experience with large storm events for the past ten years of operation has been that sheet run-off is minimal. Much of the rain water penetrates directly into the soil it initially contacts during storm events. If there is any excess sheet flow, it follows the contours of the area to the detention pond, where it remains until soaking into the ground. In regards to the fiber optic cable along the western edge of the amendment area, we will maintain a minimum of a 2:1 set-back. In other words, for every 1 foot of depth of excavation, we will stay 2 feet distance from the cable. We will flag it prior to any mining operations in the area to ensure that it not be affected in any way. If you have any questions, or need more details on the reclamation, please call me. Si9c y, Lynn E. er Regulato Compliance cc: R. A. Everist, Andesite Rock Company Kim Ogle, Weld County Planning LM/C-vIreclmrev-0 50200