2003-12-02_REVISION - M1989120 - Laserfiche WebLink

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, . Final reclamation of the site will include backfillirig the pit area closest to the South Platte River. At final reclamation, the backfilled portion of the pit will extend at least 400 feet from the river. Under,the current permit conditions, mining has been allowed to within 100 feet of the river. In areas where mining has occurred to within 100 feet of the river, the operator will backfill the pit to at least 200 feet from the river by April 2004. 18. Groundwater impacts of the current mining operation have been addressed with adjacent groundwater users. Modeling to predict.groundwater.impacts from pit dewatering was also performed results were submitted to the Division on August 2, 2002. The modeling effort .included both the current operation and activities under the proposed amendment: A copy of the modeling report is attached. The model results indicate that dewatering will lower surrounding groundwater elevations approximately two feet at a distance of 1;500 feet from the pit. The modeling effort also characterized the alluvial aquifer, which is highly transmissive and supports wells producing up to 1,000 gallons per minute. Thus, small amounts of pit dewatering induced drawdown should not have significant adverse impacts on the ability of most wells to maintain their pumping rates. Since wells do occur within the modeled pit dewatering induced drawdown area, the operator has, and will continue to address adjacent well owner concerns. Previous concerns with the current- operation have been addressed to the satisfaction of the Division and the State - Engineer's Office (SEO). If dewatering operations create future injury to surrounding wells, the applicant will continue to take all necessary actions to remedy the injuries. Mitigation measures may. include, but are not limited to: 1. Modify existing wells to operate under lower groundwater conditions. This would include re-drilling existing wells to deeper depths or lowering the pumps. All work would be done at the applicants expense with the exception of replacing equipment that was non-functional prior to mining. 2. If existing wells cannot be repaired, the applicant will drill anew well for the owner to replace the damaged well. The new well will produce water of the same quantity and quality to support the historic use. 3. Provide an alternative source of water to support the historic well water use. 19. Please see response to Item #18. 20. The proposed amendment area was investigated with a qualified environmental specialist to . . evaluate the presence of wetlands and endangered species habitat. No jurisdictional wetlands or potential endangered species habitat was identified in the proposed amendment area and the amendment azea is not located in the South Platte River riparian zone. Additionally, in _ conjunction with permitting the property directly on the west side of the South Platte River.