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Ms. Erica Crosby Division of Minerals and Geology April 5, 2006 Page 7 of 21 18. Please explain how water from dewatering of the Wattenberg West Pit will be managed to protect against pollution of surface of groundwater both during and after the mining operation (rule 6.4.7(2)(c)). As discussed in item 11 above, temporary trenches and sumps will be created to direct dewatering water away from the mining area, and/or to provide a settling area for sediments prior to discharge. Asphalt Paving Company will obtain a State CDPS discharge permit prior to off-site discharge. The reservoir operator will also obtain the necessary discharge permits to fill to and release from the reservoirs prior to their use as a reservoir. (The following additional response is from Martin and Wood Water Consultants, Inc.) The mining operations at the Wattenberg West pit will fall into two categories, those being dewatered mining and mining within slurry walled enclosures. For the former case, with respect to the proposed Phase 1 mine area, there will be local dewatering around the perimeter of the mine area in an area of the alluvial aquifer where the saturation is minimal, being less than six feet. This minimal dewatering is expected to be maintained by pumps discharging back to the alluvial aquifer via a location remote enough from the mine area to allow for minimal recycling, or via off-site discharge. The only likely concern from this operation would be the silt loading of the discharged water which can easily be managed via settlement enclosures or filter bags at the point of discharge. As the water being pumped is aNuvial water, there is no differentiation between surtace or ground water in this instance. It is our understanding that no hazardous chemical will be utilized on site and that the normal precautions with respect to machinery used at the site will be in place to prevent any hydrocarbon-related spills. When the mining operations enter the subsequent phases, Phase 2 and Phase 3, slurry walls will be installed prior to the start of mining, fully enclosing the mine areas. Under these conditions, and noting that the Division of Water Resources requires strict proof of the pertormance of such slurry walls, there will be no connection between the water inside the slurry walls and the water in the alluvium outside the walls. Once again, the usual constraints on the fuel and oil for machinery within the mined area will be in place. It is thus our conclusion that there will be no connection between the mined area within the slurry walls and the surrounding alluvial aquifer. Following the mining operations, Phase 1 will be reclaimed and the slurry walled phases will be converted into water storage vessels. Thus, there will be no future connection between the water in the storage reservoirs and the surrounding alluvial aquifer. As the water that is placed into storage will likely be pumped from the South Platte River, that being the source of water for the alluvial aquifer, in the extremely unlikely event of a failure of the slurry wall at one of the pits, the water coming in contact with the alluvial aquifer will be South Platte river (alluvial) water and no pollution issues will exist.