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The Upper Coal Bearing (Paonia) member consists of 200 to 500 feet of gray shales, interbedded, <br /> buff-colored, lenticular sandstones, and coals. The top of this member usually grades into a <br /> massive, cliff-forming sandstone. However, like the similar sandstone at the top of the Lower <br /> Coal member, this sandstone is not a single persistent bed. <br /> Three coal horizons have been identified in the Upper Coal member - the D (Oliver) horizon, the <br /> E (Hawk's Nest) horizon, and the F horizon. The D horizon occurs directly above the "massive" <br /> sandstone of the Lower Coal Bearing member and contains three seams. This horizon was mined <br /> in the Bowie No. 1 Mine. The E horizon occurs about 130 feet above the D horizon and contains <br /> two coal seams. The F horizon contains two coal seams. Coal seams of the F horizon do not exist <br /> to the north of the North Fork of the Gunnison River in thicknesses sufficient for mining. <br /> The Barren(Undifferentiated)member of the Mesaverde Formation consists of up to 1,500 feet of <br /> terrestrial sedimentary rocks. This unit consists of fine-grained, buff-colored, lenticular <br /> sandstones, gray shales and thin, lenticular coal beds. The sandstones predominate and are highly <br /> lenticular, discontinuous and of limited lateral extent in outcrop. <br /> The Mesaverde Formation is unconformably overlain by the Tertiary Age Rudy or Wasatch <br /> Formation. This formation consists of red to buff-colored shales, red sandstones, and red to gray <br /> conglomerates. The sediments of this formation are weathered volcanic rocks. The Ohio Creek <br /> conglomerate is the basal unit within the formation and is 100 to 200 feet thick. <br /> Tertiary igneous intrusive rocks exist within the North Fork drainage basin. A diorite plug about <br /> 1,000 feet in diameter outcrops along Hubbard Creek in the SE 1/4 of Section 7, Township 13 <br /> South, Range 91 West of the 6th P.M. This may represent the erosional remnants of a volcanic <br /> flow feeder. Sills have injected the Lower Coal Bearing member, particularly the B and C seams. <br /> These sills consist of diorite and appear to have their source to the northwest of Terror Creek. <br /> Hydrologic Balance - Rules 2.04.5, 2.04.7, 2.05.3,2.05.6(3), 4.05 <br /> Groundwater <br /> Groundwater information can be found Sections 2.04 and 2.05.6 of Volume 1 of the PAP. Water <br /> quality documentation may be found in Volume 4 and is supplemented by annual hydrologic <br /> reports prepared since 1982. For a description of the groundwater hydrology of the mine area and <br /> a discussion of the impacts of mining on groundwater, please refer to the Hydrologic Balance <br /> portion of Section B of this Document. <br /> Three categories of potential aquifers occur in the general area. These are alluvial and terrace <br /> deposits associated with the North Fork of the Gunnison River, the localized shallow <br /> alluvial/colluvial areas in the stream drainages, and groundwater in the lenticular sandstones and <br /> the Rollins Sandstone of the Mesaverde Formation. <br /> The most significant occurrence of groundwater in the general area is associated with the alluvium <br /> of the North Fork of the Gunnison River, located approximately two miles southeast of the mine <br /> 8 <br />