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IV. Geology (2.04.5, 2.04.6) The operation lies on the northwestern rim of the San Juan Basin, within the Colorado Plateau Province. Structurally, the area is characterized by slight southerly dips away from the LaPlata mountains to the north. Mining operations will extract the upper seam of the Menefee formation which is the middle member of the Mesa Verde group. The upper Menefee seam is approximately six feet thick, dips 3.4o south and strikes S35oW. Overlying the Menefee formaticn is the Cliff Xouse formation and underlying it is the Point Lookout formation. The Cliff House formation is of marine origin and composed of fine to medium grained sandstone, muds tone and silty shale. The basal formation of the Mesa Verde group is the Point Lookout sandstone. The Point Lookout sandstone is divided into two members: The upper member is a massive sandstone consisting of even-textured, medium-grained sandstones; the lower member consists of thin sandstone beds interspersed with shale. This is a transitional zone above the Mancos shale which underlies the Mesa Verde group. Sampling of the roof and floor material, as well as the coal, has been performed by the operator. Based on these analyses, the Division has determined that the only possible acid- or toxic-forming material will be the coal itself, due to its sulfur content. Since the workings are essentially dry, however, no impact is projected. (See X - Hydrologic Balance - of this findings document for a more detailed discussion of this issue.) Lptails of the chemical character- istics of the roof, floor, and coal, as well as greater detail on the geology of the area, can be found in Sections 2.04.5 and 2.04.6 of the permit application. The proposed operation is in compliance. V. Ground Water Hydrology (2.04.5, 2.04.7, 2.05.6(3), 4.05) Within the potentially affected area of the mine, ground water occurs within an alluvial aquifer and a bedrock aquifer. The alluvial aquifer is Hay Gulch, lying adjacent to the existing surface facilities. The bedrock aquifer is the Point Lookout sandstone, Iying strati graphically 275 feet below the seam being mined. The geologic strata above and immediately below the mine workings appear to be dry. The operator has not encountered ground water in the mine workings during over 40 years of operation. In addition, no water was encountered during the applicant's drilling program, in which one hole was drilled, penetrating the coal seam and found to be dry. Ground water use in the vicinity of the mine appears limited. Within a one-mile radius of the proposed permit area, one spring and two water wells were encountered. The spring occurs as a seep in the Hay Gulch alluvial aquifer and lies hydro- logically above the proposed permit area. The water wells are used by the mining operation and located in or adjacent to Hay Gulch on the existing mine bench. Both wells are registered with the Colorado Division of Water Resources and completed in alluvial gravels or terrace deposits of Hay Gulch. There are no known users of bedrock ground water within the vicinity of the mine.