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LO Introduction system. Three USGS springs have been identified in the canyon and appeaz out of fractures between sandstones and shales which outcrop on the surface. Cover is comprised mostly of woodland. Grazing and wildlife aze the major land uses. Mining was also a land use with an exhaust shaft and a power substation located in the canyon. Longwall mining panels perpendicular to the direction of flow underlie the canyon. During 1989, a determination was made that the canyon does not meet alluvial valley floor criteria (see Exhibit 30 of the Golden Eagle Permit Document). The geologic setting is an important factor when analyzing hydrology of an azea. Stratigraphy in the region ranges in age from Pre-Cambrian to Quaternary. However, only portions of the Raton Formation (see Figure 1.1-1) and recent alluvial deposits are exposed in the azea of the mine. Most of the formation consists of very fine to medium grained sandstone interbedded with siltstone and shale. Coal that was mined at the Golden Eagle is located near the middle of the Raton Formation. The outcrop of the formation in the area may be chazacterized as stream deposits including channel-point baz facies, floodplain deposits and swamp deposits. Alluvial deposits along the Purgatoire River are complex. The headwaters of the river are underlain by volcanic rocks and sediments. As it flows to the east, the river cuts its way through many different geologic formations including Pleistocene glacial-fluvial sediments, foothills belt of Paleozoic-Mesozoic strata, terestrial sediments of the Tertiary, and marine deposits of the Pierre Shale. Chazmel shape and structure of the Purgatoire vary within each of these formations as does the water quality. Alluvial deposits in the area of the mines range from their curent location to older terraces of forty to fifty feet above the Purgatoire. Buried channels which aze incised into the underlying Raton Formation have also been fouhd. Purgatoire River alluvial deposits support typical hydrophytic vegetation chazacteristic of floodplains and contain groundwater hydrologically connected to the Purgatoire River. The Picketwire Valley of the Purgatoire River alluvial deposits has been designated as an alluvial valley floor and is classified as a renewable resource. Soils are generally shallow and coarse-grained. They aze derived from the underlying sandstones and shales. Bedrock exposures are common and scattered throughout the area. The valley bottoms are characterized by alluvial and colluvial deposits which aze also coarse-grained and deeper than soils of the mountain slopes. Vegetation vanes from riparian and blue grama complexes in the valley bottoms to pinion juniper, oak brush, and pine cover on the side slopes. Vegetation cover ranges from 100 percent in the valley bottoms to none on the steeper side slope rock outcrop areas. The neazest weather station to the mine site is located at the Trinidad Airport (elevation 5,746 feet) approximately 30 miles east. Over a recording period from 1961 to 1990, total annual precipitation averaged 13.5 inches. The majority of this precipitation (65%) occurs from May to September. July usually has the most rainfall. The mean annual temperature is 51.8 °F. January is the coldest month with a mean temperature of 32.9 ° F, and July is the warmest month, showing a mean of 60.2 ° F (Owenby and Ezell, 1992). The project area is approximately 1650 feet higher in elevation than the Trinidad Airport and can be considered to have 5 ° Flower mean temperatures and higher average precipitation. Surface water availability is drrectly related to precipitation received in the drainage. The climate summary, as described in the mine pernut document, projects a mean annual precipitation near the mine of 16.92 inches. 29234 Golden Eagle Mine Rpt (5.10.06).doc 1-2