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-13- <br />Colorado Westmoreland mines the D seam of the Upper Coal member of the Mesa <br />Verde formation. The seam ranges in thickness from two (2) to twenty-two (22) <br />feet in the permit area, with one split ranging in thickness from 15 1/2' to <br />several inches. The coal dips 4-7 degrees to the northeast. Two high angle, <br />normal fault zones are found in the area with displacement ranging between one <br />(1) and fifty (50) feet (Map 2-8 ). The earliest fault system trends N65°E and <br />dips 70°-80° with displacements of two (2) to six (6) feet. The other fault <br />system trends N35 W and dip 70°-80° to the northeast. The geology is further <br />modified in the northeast corner of Lease ~C-37210 where coked coal gives <br />evidence of igneous activity associated with the Miocene Iron Point pluton. <br />CWI is constructing a waste rock pile for underground development waste. <br />During the first nine months of 1987, 23,395 cubic yards were placed in the <br />pile. A total of fifteen (15) roof, floor, coal, and interburden samples from <br />existing areas within the Orchard Yalley Mine have been collected and analyzed <br />according to the Division's Guidelines. The sampling locations are depicted <br />on Map 6A-8 and results of the chemical analyses are presented in the Waste <br />Disposal section of Yolume 6A. A limited number of samples show high levels <br />of boron and zinc while SARs of all samples are high. SARs range in <br />concentration from 18.5-136 and average 49.4. <br />In order to monitor the material exposed in the mine on a continual basis, CWI <br />has committed to collecting additional samples of roof, floor, interburden and <br />coal samples at locations depicted on Map 25, and at other supplemental <br />locations where inordinate concentrations of waste rock are encountered (i.e.: <br />roof falls, rockwork, etc.). The results of these geochemical analyses will <br />be reported annually in conjunction with the Annual Subsidence and fydrology <br />Report (page 32, Section 2.04.6 of the permit application). <br />This on-going sampling program will serve to satisfy concerns to the quality <br />of waste rock refuse pile material and verify predictions of impact to <br />post~nining ground water quality. The permit application is in compliance <br />with the requirements of this section. <br />Y. HYDROLOGIC BALANCE: (2.04.5, 2.04.7, 2.05.3, 2.05.6(3), 4.05) <br />Ground Water <br />Ground water information can be found on pages 27-41 of Section 2.04 and on <br />pages 114-135 of Section 2.05.6 of Volume 1. Water quality documentation many <br />be found in Volume 4 and is supplemented by annual hydrologic reports prepared <br />since 1982. Fora description of the ground water hydrology of the mine area <br />and permit revision area and a discussion of the impacts of mining on ground <br />water, please refer to the Regional Geology and Ground Water Fydrology portion <br />of Section IX, Probable Iydrologic Consequences and Cumulative Impact <br />Assessment of this document. <br />CWI monitors twenty-six springs monthly during the field season for <br />temperature, conductivity, pH and flow and quarterly monitoring of major <br />cations and anions. In addition, there are multiple deep bedrock wells, fill <br />piezameters, alluvial-colluvial sites and alluvial wells which are monitored <br />regularly. ~ <br />As discussed in the Probable Hydrologic Consequences section, dewatering from <br />fracture flow, whether natural or subsidence-induced, is a potential impact of <br />