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iii iiiiiiiiiiiii iii <br />999 <br />DEPARTMENT OF NATURAL RESOURCES <br />David H. Getches, Executive Director <br />MINED LAND RECLAMATION DIVISION <br />DAVID C. SHELTON, Director <br />Richartl D. Lamm <br />Governor <br />DATE: March 28, 1984 <br />T0: Bob Liddle <br />FROM: P. C. Saletta ~ ~ / <br />RE: Colorado Westmoreland, Inc. <br />Annual Hydrology Report (1983) for the Orchard Valley Mine <br />As per your request, I reviewed a]1 data submitted by CWI for the Orchard <br />Valley Mine AHR. The report specifically responds to all the requirements of <br />Stipulations No. 2, 3 and 4 of the Orchard Valley Mine Findings Document. In <br />addition, subsidence survey and monitoring data is submitted. <br />The report has a narrative which discussed 1983 hydrologic impacts and <br />hydrologic balance and projected impacts for 1984. In the section entitled <br />"Hydrologic Impacts", the author discussed mine inflow which were the result <br />of small seeps from paleochannel sandstones overlying the coal seams. <br />Reported inflow is from small weeps or dripping conditions which generally <br />discontinue after 60 days. There was no apparent injury or diminution of <br />surface water or springs due to mining 1n 1983. Geochemical analysis of grab <br />samples indicate that these are sodium-bicarbonate rich waters, with low <br />concentrations of metals. <br />Presently, in the area being mined, ground water inflow is not a problem. <br />This is also indicted by the deep monitoring well, DH-70 which has a depth to <br />water of greater than 475 feet below the surface. Sample analyses from this <br />well correlate well with analyses of mine inflows. The relatively dry <br />conditions of this mine are also evident in the water consumption (8-10 <br />million gallons) for dust suppression and fire prevention during 1983. <br />The report included a comp11at1on of all measurements and analyses of samples <br />taken at surface sample sites. This reporting could be specifically Improved <br />upon in terms of the measurements. Values submitted to the Division should be <br />flow rates, not just the measured depth 1n the flume. Although the monitoring <br />stations results are low flow, less than 15 gpm, I believe to maintain <br />consistency, flowrates should be submitted. <br />Geochemical results from samples indicated no degradation of water quality <br />from 1982 to 1983. Data is compiled in table form in the report by sample <br />area location and can easily be followed for review. <br />423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. (30~! 866-3567 <br />