2015-09-18_REVISION - M1980183 - Laserfiche WebLink

Home Browse Search

Mr. Tyler O'Donnell RE: Adequacy Review Response September 18, 2015 Page 2 of 4 drain design has a 3 -foot change between A and A'. The Division believes that the gradient of the french drain should closely match the pre -mining groundwater gradient. Please lower the design elevation ofA by I foot, to 5009 feet. If the applicant lowers the design elevation ofA by I foot this will closely mimic the pre -mining groundwater gradient and elevations. The figure for Exhibit E has the correct elevation of the east end of the french drain at 5009' The text was incorrect. The following is the corrected text, with changes in bold. During review I also noted other typographical errors in this paragraph and I have added some clarification. The elevation of the french drain is shown on Exhibit E. The upgradient (east) end of the drain is at the elevation of 5009', see profile A' -A.. The down gradient end (western terminus) of the french drain, located at the southwest corner of Pit 29's North Cell and shown on A' -A, is at the elevation of 5007'. During the flooding in Fall 2014 we measured the water surface in the Einspahr pasture just south of the North Cell at 5011.1'. The low points in the pasture are approximately 5011'. Therefore, we propose to maintain the ground water level at the western terminus a minimum of 4 feet below the surface (50071). We agree with you that this will closely mimic the pre -mining groundwater gradient and elevations. EXHIBIT N — Source of legal Right to Enter: 4) The western portion of the proposed french drain crosses property owned by Adams County. Please demonstrate that the Applicant/Operator has legal right to enter the property owned by Adams County to construct the french drain. Attached is the crossing permit from Adams County. EXHIBIT L — Reclamation Costs: 5) Please see the enclosed cost estimate. The Division has accepted your cost to construct the french drain and has accepted other cost provide by you in previous permitting actions. The Divisions has also enclosed the cost estimate from AM -01. Please review the enclosed cost estimate, and provide any comments you may have. We have reviewed the cost estimate provided by the DRMS. We agree with the cost estimates you provided, with the exception of Task 004, Riprap banks (cost from AW -02). We request that this item be eliminated, resulting in a total reclamation cost of $583,821. We believe there is no need for the riprap as originally designed. We calculated the wind run up based on NOAA climate data for prevailing and wind gusts. Based on NOAA data, the prevailing wind averages 10 mph and the wind gust average is 62 mph. The run up on the