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MINItJG AND RECLAPIATION PLAN III III'llllllllllll January 1986 MT. GUNCIISON NO. 1 MINE 999 Revised April 1989 Revised October 1989 2.7 Geology • 2.7.1 Data Collection Since 1967, when the first lease was purchased, 112 exploration hales have been drilled across the block. Ninety-one of these holes have been drilled since 1972. Since 1982, additional wells have been drilled for various types of data collection. Below is a listing of the well numbers, purpose and appendix where additional information can be found. Well No. 1982 Drill Holes 2&3* 1984 A 1-3 1984 GP 1-5 1984 SOM l0A 1985 SW 1-6 1985 SOM 38-H-3 1986 SOM 4A 1987 SOM 122-126 1988 SOM C-72, A,B,H SOM 127-H Purpose Appendix Coal Quality B-2 AVF Monitoring D-5 Refuse Pile Monitoring B-9 Coal Quality A-7 Subsidence Hydrology A-19 Subsidence Hydrology A-19 Coal Quality A-24 Coal Quality/Hydrology A-27 Coal Quality/Hydrology A-29 Coal Quality/Hydrology *4 holes were permitted, but only Holes 2 and 3 were drilled. Generally, the drill holes are rotary drilled with air, foam, or • mud and cored for quality and/or geotechnical analyses. Lithologic and other logs of the drill holes may also be obtained. The logs, drill hole location map(s), and completion data are submitted to the regulatory authority, as required. The monitoring wells are completed and abandoned in accordance with all applicable regulations of the Division and of the State Engineer's office. Well completion data and test results are submitted with the Annual Hydrology Report. Permits will be obtained from the surface landowner, as necessary, prior to preparation of the drill pad or road(s). Approximately five holes per sectiop at the Mt. Gunnisop No. 1 Mine area have been cored on the best spaced pattern obtainable considering topography and access. Since 1973, the drilling procedure has been to rotary drill to a projected point 250 feet above the E seam. At this point, casing was set and the hole was cored from there to the top of the Rollins sandstone, usually a distance of about 550 feet. Upon completion of drilling, a package of geophysical logs was run on each hole. This package included various combinations of gamma ray, neutron, density, resistivity, self-potential and temperature logs. These holes are designated SOM for those drilled over Federal coal and MG for those drilled over private coal. In addition, four holes were drilled on the lease area by the U.S. Bureau of Mines (BOM) in the 1940's which were given a G destination. Location, • elevations, and total depths of holes are shown on Exhibit 2.7.1.A. In addition to core drilling, extensive surficial and aerial photo work has been completed to supply basic geologic data. 2-283