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since; 1. No intermittent or perennial streams cross the retreat mining area or are adjacent to the <br />area, and 2. Discharges to surface waters will be in compliance with NPDES/CPDES permit <br />requirements. <br />Mountain Coal Company water withdrawals from the North Fork are not expected to cause any <br />impact since they are a small percentage of stream flow even during low flow conditions. <br />No U.S. Forest Service water resources are located in the permit area projected to be retreat <br />mined. Resource No. 131 is located over the projected B-Seam main entries;: but is not expected <br />to be impacted. See the additional discussions of mitigation measures in Section 2.05.6(6)(f) and <br />in Exhibit 19C. <br />The Mountain Coal Company Water Augmentation Plan was adjudicated in February, 1987, in <br />, . Division 4, State of Colorado Water Court. A copy of the Adjudicated Water Augmentation Plan <br />is included in Exhibit 52. The water augmentation plan covers mitigation of potential impacts <br />from mining in the Minnesota Creek Basin. The water augmentation plan is based on worst case <br />conditions where mining in the basin depletes the Dry Fork of Minnesota Creek and requires <br />augmentation by Mountain Coal Company water rights up to 10.96 cubic feet per second (4919 <br />gallons per minute) maximum headgate diversion. <br />The plan is not in effect during development mining in the basin. However, there is a provision <br />to implement the plan should circumstances warrant, such as large inflows into the mine <br />workings in the Minnesota Creek Basin. <br />Mountain Coal Company provides in the Annual Hydrology Report (AHR) a detailed assessment <br />of minting impacts of the past water year as well as potential mining impacts and an estimate of <br />production for the upcoming water year. A map is included in the Annual Hydrology Report <br />showing the piezometric surface of the colluvial aquifer in the area of the Lower Refuse Pile, if <br />one develops. An assessment of the impacts of the Lower Refuse Pile to the hydrology balance <br />during the previous year is included in the report. Also included in the report are the analyses of <br />hydrologic data gathered during the year to assess the impacts of mining on the quality and <br />quantity of streams, springs, groundwater aquifers, mine inflows and mine discharges (water <br />balance) which may exist in the permit area. Mine maps showing the locations of mine inflows <br />are provided in the Annual Hydrology Reports along with estimates of the quantity, quality and <br />duration. Water quality samples will be taken as close to the inflow source as safely possible, to <br />properly characterize the water quality. Estimates of water imported for use within the mine and <br />mine discharge are also provided in the reports. The Annual Hydrology Report will include <br />seasonal measurements of spring flows, streamflows, well levels, and water quality analyses of <br />selected parameters for each monitored resource. Mountain Coal Company also evaluates the <br />adequacy of the current monitoring plan in the report. The Annual Hydrology Report will also <br />include an anion and cation balance on all water analyses. This will provide a quality <br />assurancelquality control check on the laboratory data. <br />2.05-~ Revised Dec. 1997 MR208; Revised Jvn. 1999 TR90 <br />~1~ Revised May 2003 MR-294 <br />