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• 'ven th~-t these horizons have very similar depositional and physical <br />Gi <br />characteristics, they have been mapped as a single undifferentiated unit. <br />colluvial/Alluvium deposits cover most bedrock outcrops in the mine area, <br />with depositional thicknesses ranging from 5 to over 100 feet. The <br />colluvium~/alluvium consists primarily of boulder and cobble size material <br />dominated by gneiss, schist, and sandstones derived from erosion and mass <br />wasting of the Wet Mountain uplift to the south and west. The boulder and <br />cobble materials are unconsolidated to moderately consolidated with a clay <br />matrix. <br />The stratum to be affected in the Southfield loadout area is limited to <br />the colluvial/alluvial deposits typically present throughout the Canon <br />City Basin. These materials are generally less than 20 feet thick in the <br />loadout area. No footings, excavations or foundations will penetrate the <br />colluvial/alluvial materials to impact the underlying Pierre Shale. <br />• Characteristics of Coal and Overburden <br />Southfield has utilized geologic data from various sources obtained <br />between 1956 and the present to evaluate physical and chemical <br />characteristics of coal and non-coal strata within the Southfield permit <br />area. The majority of this data is the result of extensive exploration <br />drilling, geophysical logging and laboratory analyses of coal, roof, and <br />floor sartiples. <br />Location of Subsurface Water. The initial circulation medium for several <br />exploration coreholes within the mine permit area was compressed air. The <br />return air provided a rapid and reliable indication of the existence of <br />subsurface water. The only significant subsurface water encountered <br />within the strata to be affected by current and proposed mining <br />activities, is associated with abandoned mine workings. <br />Numerous perched groundwater reservoirs have been encountered throughout <br />• the Raton and Vermejo Formations. Perched groundwater has been found in <br />various locations and aut varying elevations throughout the permit area. <br />