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The Orchard Valley mine lies oa the southeast margin of the Piceance Basin. <br />Sedimentary rocks ranging from late Cretaceous to early Tertiary age, and <br />• dipping 5 degrees north, are exposed is the mine areas. <br />Three categories of potential aquifers occur is the general area. There are <br />alluvial and terrace deposits associated with the North Fork of the Gunnison <br />River, and the localized shallow alluvial/colluvial areas in the stream <br />drainages, and ground water is the lenticular sandstones and the Rollins <br />sandstone of Hesaverde Formation. The most significant occurrence of ground <br />water in the general area is associated with alluvium of the North Fork of the <br />Gunnison River, located approximately 2 miles southeast of the mine portals <br />and 1,500 feet lower in elevation. <br />The recharge to the Steven's Gulch well field area is through flow from the <br />adjacent colluvial deposits and from a leaky pipeline aqueduct. The ground <br />water flows through the colluvium downslope to the alluvium, where it becomes <br />trapped or temporari]y stored. <br />Water quality analysis for the Steven's Gulch well water indicates good <br />quality water, with none of the parameters exceeding the recommended standards <br />of the U.S. Public Health Service. <br />Alluvial/colluvial deposits in the Terror Creek drainage~aear the Horrell Cow <br />Camp are also being utilized for water supply purposes. However, no impact is <br />predicted for these areas. <br />Occurrences of ground water have Deen noted in the Hesaverde Formation from <br />• inforoation obtained from drilling, experience is the mine and from the <br />presence of springs and seeps in the permit area and hydrologically adjacent <br />area. This information indicates that the only potential regional aquifer in <br />the area is the continuous Rollins sandstone, located stratigraphically <br />approximately 200 feet below the "D" coal seam. Due to the steepness of the <br />topography in the outcrop areas (i.e. sandstones are cliff formers) and the <br />narrowness of the stream valleys, the Rollins sandstone receives little <br />recharge. <br />Ground water occurrences in the stratigraphic interval of the Hesaverde <br />Formation above the "D" seam are a function of the depositional environment <br />and are characterized by saturated horizons of localized lateral and vertical <br />extent, separated by low porosity, unsaturated intervals. These saturated <br />horizons do not appear to contribute significantly to overall regional ground <br />water flow. <br />Impacts to the Environment <br />Based oa information submitted by CWI, analyses conducted by the MLRD and OSM <br />and consultation With other Federal agencies, there will be ao additional <br />impacts other than those that have been identified in previously cited <br />documents to the following resource categories: topography, geology, climate, <br />air quality, soils, vegetation, wildlife, cultural resources, land use, <br />transportation, esthetic, anise or health and safety. Therefore, these <br />resource categories will not be discussed further. Resource areas which could <br />• potentially experience additional impacts are hydrology, socioeconomic, <br />subsidence and fish and wildlife (threatened and endangered species and <br />raptors). <br />4 <br />