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~~ Summdry The Review Process The Division received a complete application for Permit Renewal No. 02 on October 4, 1992. Acknowledgement of this was made to the operator. Public notification began October 14, 1992 for four consecutive weeks in the Pagosa Springs Sun newspaper. Staff comments generated in regard to adequacy issues identified during review of the proposed revision were conveyed to Greystone Development Consultants in a letter dated December 9, 1992. All adequacy issues were resolved; therefore, the Division is proposing to approve the application for Permit Renewal No. 02. Description of the Environment The Chimney Rock operation is located in southwestern Colorado approximately 22 miles southwest of Pagosa Springs. The permit area lies in the upper rim of the San Juan Basin at an elevation of approximately 6,400 feet. The San Juan Basin is an asymmetric structural basin in northwestern New Mexico and southwestern Colorado. Rocks in the area are sedimentary, of marine and non-marine origin. Sedimentary rocks were formed through the transgression and regression of an epicontinental sea. Mined coal seams are located in the Lower Fruitland Formation. This formation is composed of interbedded sandstone, siltstone, shale, carbonaceous sandstones, and coal. Three coal seams of economic importance were found in this formation; mining operations removed coal from all three seams. Ground water occurs in the sandstones of the Fruitland Formation, the Pictured Cliffs Formation, and in the alluvium associated with Stollsteimer Creek. The permit and adjacent areas of the mine are located within the Stollsteimer Creek Drainage Basin, which is tributary to the Piedra River. Small intermittent and ephemeral tributaries drain the permit and adjacent areas. The yearly amount of precipitation received at the mine site can be expected to range from 15 to 20 inches. Rainfall accounts for 15 to 45 percent of the precipitation, with the majority occurring during the late spring (May) and during late summer (August and September). Mean annual temperatures range between 45°F and 48°F. Maximum mean temperatures occur between May and September and average 73°F. The average minimum mean temperature during the same period is 43°F. Frost-free days range from 75 to 115 days. Average summer relative humidity is estimated to be 34 percent. This is associated with increased rainfall received during the warmer months. The average annual relative humidity is 20 percent. Wind direction is predominantly from the southwest. Soil types within the permit area include the following mapping units: Carracas variant - Peney variant, Celacy variant loam, Munn variant loam, and -3-