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Rule 2.04 <br />• Principal groundwater bearing zones in the general mine area are recent alluvial deposits and the <br />coals and mazsive sandstones of the Williams Fork and Iles formations. Typically, the <br />moderately permeable sandstone units are separated by low permeability shales which act as <br />aquitards. Groundwater in the region generally moves to the nonh as the Cretaceous <br />sedimentary units dip to the north. Near the mine permit area, groundwater moves to the <br />northeast following the dip of strata toward the axis of the Watering Trough syncline which <br />runs north-south just to the northeast of the mine permit area. Both the 20 Mile and Trout <br />Creek sandstones of the Mesa Verde formation constitute significant regional aquifers and are <br />present below the coal seams at Hayden Gulch. Regional wells in the alluvium reportedly <br />produce up to 1500 gpm and Mesa Verde wells reportedly produce up to 300 gpm. <br />A total of 18 spring and seep areaz were located within one mile of the mine permit boundary. <br />Analysis of water quality data, geology and spring flow data indicated that all bu[ four of the <br />springs or seeps originated from water bearing zones below the mining zone. <br />2.04.6 Site Geology Description <br />r1 <br />U <br />• <br />The original permit application described both regional and site specific geology with respect to <br />physiography, structure, stratigraphy and aquifers in Section 2.04.6 of Volume /. A detailed <br />discussion of site and regional geology waz also prepared by the CMLRD as part of the 1987 <br />permit renewal and is included in Appendix E, January 1987 Proposed Decision and Findings <br />of Compliance. <br />Nature of Coal and Overburden <br />The Hayden Gulch mine property contained five coal seams that dipped at approximately 5 to <br />10 degrees in a northeasterly direction. The seams varied in thickness from 1.2 - 7.0 feet with <br />a combined average of approximately 2.2 feet. The average overburden and interburden ranged <br />from approximately 9.0 - 50.0 feet between coal seams. <br />Coal quality was characterized by medium Btu and low sulphur content. Table 2.041 presents <br />weighted average proximate analyses results for "typical" H-G coal. <br />TABLE 2.04-1 <br />PROXIMATE ANALYSES <br />les received) <br />Element or Compound Average Range <br />Moisture - 17.51 16.42 - 19.59 <br />Ash 6.24 5.14 - 8.74 <br />Volatile Matter 33.31 32.40 - 34.03 <br />Fixed Carbon 42.93 41.96 - 43.93 <br />Sulphur 0.43 0.34 - 0.79 <br />Btu/Ib 9978 9642 - 10172 <br />H: ~B]]\PEAM R\R ULE2~01. HG <br />ll/39/959:~4am WP51/cmc 2.04-5 Revised - 11/28/95 <br />