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West Elk Mrne <br />~~ 2.04.6 Geology Description <br />Introduction <br />The following geologic description of the West Elk Mine permit azea is based on publications by <br />C.R. Dunrud (1976), W.R. Junge (1978), Ellis, Gaskill, and Dunrud (1987) and C. Richard Dunrud <br />(1989); unpublished reports by V. H, Johnson (1948), Geo-Hydro Consulting (1980), Dames & <br />Moore (1983) and Intraseazch, Inc. (1993); considerable subsurface and surface investigations by <br />ARCO (now Mountain Coal Company [MCC]) staff geologists, aerial photo and low altitude aerial <br />and field reconnaissance studies by C.R. Dunrud and J.W. Rold (1994 to 1996), and results from <br />more than 238 drill holes on or near the property. The location of these drill holes is shown on Map <br />8. ~ <br />Holes are designated "SOM" for those drilled over Federal coal and "MG" for those drilled over <br />private coal. Four holes were drilled on the lease azea by the U.S. Bureau of Mines (USBM) in the <br />1940's which were given a G designation. Twenty-five (25) holes were completed in 1963 by the <br />U.S. Steel Corporation and designated with the "CSM" prefix. Five additional holes were drilled <br />by Grand Mesa Properties in 1981 and designated "MG-***=81." Grand Mesa Properties <br />completed another hole (CP-82-1) in 1982. In 1992 and 1993, Mountain Coal Company completed <br />13 drill holes through the B-Seam and were given the designation "JMB," Three holes were drilled <br />to the southwest of the mine site in 1994 and were designated "So. W." (These holes shouid not be <br />confused with the shallow wells completed for the subsidence monitoring program and designated <br />I~ as "SW-1" through "SW-6"). Holes drilled from 1993 to 1995, to the east of the mine site, towazd <br />or on Raven Mesa have been designated "RAV". In 1996, 17 holes were drilled and completed <br />through the B-Seam. They are designated as 96-*-*. The fast entry indicates the yeaz that the hole <br />was drilled. The second entry indicates the section in which the hole was drilled, and the third entry <br />indicates the numbered hole in that section. <br />Subsurface control; coal distribution, coal thickness, and quality; overburden and interburden <br />thickness and chemical characteristics; structural geology and stratigraphy have been derived by <br />using all of the drill holes. More than 64 holes have been drilled on or within a quarter mile of the <br />Apache Rocks and Box Canyon permit revision azeas. The location of those drill holes are <br />included on Map 8. All holes were drilled with permission of landowners and pemuts from <br />appropriate state and federal regulators. Monitoring wells shown on Map 34 and other holes shown <br />on Map 8 were completed or abandoned and reclaimed in accordance with all applicable <br />regulations of the Colorado Division of Minerals and Geology (CDMG) and the State Engineer's <br />Office (SEO) in place at the time. Well completion data and test results have been submitted to the <br />CDMG with Annual Hydrology Reports. Completion data aze also; provided in Exhibit 12. <br />Normal practice from 1973 through 1991 entailed rotary drilling io approximately 250 feet above <br />the E-Seam where casing was set and coring continued downward through the B-Seam. Since <br />1992, procedures typically only included spot coring of the E and B-Seams and immediately <br />adjacent strata. The typical suite of geophysical logs run on each hole consisted of various <br />. combination of gamma ray, neutron, density, resistivity, self-potential, temperature logs, and <br />caliper. <br />I.04-I S November 2004 PRlI <br />