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Description of t~Environment • <br />The Red Canyon Mine is located approximately five miles northwest of <br />Cedaredge, Colorado (Figure 1). The 610 acre permit area lies on the lower <br />south facing slope of the Grand Mesa, which is on the southern flank of the <br />Piceance Creek Basin. Grand Mesa lies north of the mines and rises over 4,000 <br />feet above the elevation of the portal area in less than 4 1/2 miles. The <br />combination of rising topography and dipping coal beds results in rapidly <br />increasing overburden thickness to the north. <br />The mine elevation is approximately 6,400 feet. The climate is semi-arid with <br />an annual precipitation of 12-14 inches. Predominately south and west <br />exposures in the surface disturbance area combined with the low precipitation <br />have resulted in poorly developed soils and sparse vegetation in the portal <br />area. <br />The permit area is within the Tongue Creek watershed, a tributary of the <br />Gunnison River. Ward Creek, a perennial stream, and Williams Creek, an <br />intermittent stream are the major drainages within the permit area. The <br />facilities area is located on an ephemeral tributary of Ward Creek. Both Ward <br />and Williams Creek are calcium bicarbonate waters with low salinities (TDS <br />ranging from 100-300 mg/1). A number of irrigation ditches operated by the <br />Granby Ditch and Reservoir Company supply water to orchards and pastureland in <br />the Williams and Ward Creek Valleys, and adjacent to the permit area. <br />Alluvial valley floors, currently supporting irrigated agriculture, have been <br />identified in the permit and adjacent area. <br />The Red Canyon Mine plan called for mining of two coal seams (the D and the E) <br />which occur near the base of the Upper Cretaceous Mesa Verde formation, a <br />300-350 foot section of non-marine siltstone, claystone and channel sandstone <br />deposits above the Rollins Sandstone. Only a portion of the E seam was mined; <br />it averaged six (6) feet in thickness and dipped 3-5 degrees to the northeast. <br />Overburden thickness ranges from less than 100 feet near the portals to <br />approximately one thousand feet at the northern permit boundary. <br />A surficial "glacial-alluvial" deposit mantles a major portion of the permit <br />area. The deposit is fully saturated in most areas and is a regionally <br />significant aquifer. The only other aquifer of significant regional extent in <br />the permit or adjacent area is the Rollins Sandstone, which is approximately <br />300-350 feet stratigraphically below the proposed "D" seam workings. <br />Potential impacts from underground mining could involve drawdowns in the <br />glacial-alluvial deposit from subsidence. Grand Mesa has designed their mine <br />plan to prevent subsidence, performs detailed monitoring of the aquifer, and <br />has adequate water rights to supplement the aquifer if repair measures proved <br />unsatisfactory. <br />-4- <br />