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20 to 120 feet above the Rollins sandstone. The Chorizon contains one coal seam that occurs 50 <br />to 100 feet above the B horizon. <br />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 />Hvdrolop-ic Balance - Rules 2.04.5. 2.04.7. 2.05.3, 2.05.601, 4.05 <br />Ground Water <br />Ground water 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 ground water hydrology of the mine area and <br />a discussion of the impacts of mining on ground water, please refer to the Hydrologic Balance <br />portion and the Probable Hydrologic Consequences 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 ground water in the lenticular sandstones and <br />the Rollins Sandstone of the Mesaverde Formation. <br />