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Ground Water <br /> Aquifers of particular interest in the permit area include the coal and interbedded units of the <br /> Williams Fork Formation Middle Coal Group as well as the overlying Twentymile Sandstone <br /> and the underlying Trout Creek Sandstone. Bedrock groundwater is confined except in <br /> outcrop areas. Baseline studies showed that the Lennox Overburden and Coal units are <br /> artesian flowing aquifers. The Wadge Overburden occurs under confined and unconfined <br /> conditions as does the Wolf Creek Coal. No significant faulting is known to occur within the <br /> permit area. Alluvial aquifers in the permit area include the Sage Creek alluvium, Annand <br /> Draw alluvium and Grassy Creek alluvium. Groundwater occurs under unconfined conditions <br /> in the alluvial aquifers. Movement of groundwater in the alluvial aquifers is controlled by the <br /> characteristics of the stream drainages within which they occur. <br /> Impacts to surface water and ground water continue to be monitored. Surface runoff from all <br /> disturbed areas is channeled to one of several sedimentation ponds. Ponds 010, 011, 011A, 012, <br /> 012A, 013, and 014 exist at the site. Surface water is monitored upstream and downstream of the <br /> site on Grassy Creek, Armand Draw, and Sage Creek. Ground water is monitored in the Trout <br /> Creek aquifer,in spoils aquifers, natural springs, and in the alluvium of Sage Creek, Grassy <br /> Creek, Armand Draw, and Grassy Creek tributaries. <br /> Climate <br /> The average annual precipitation of the town of Hayden, Colorado, 8.5 miles northwest of the <br /> mine site, is approximately 15.9 inches. Precipitation for Hayden is relatively uniform <br /> throughout the year. The mean annual temperature is 42°F, with an average maximum and <br /> minimum temperature of 66°F and 17°F, respectively. The predominant wind direction at the <br /> Seneca IIW Mine, located west of the Yoast Mine, is from the east southeast. This direction is <br /> in conformance with the topography of the site and therefore may not be indicative of expected <br /> wind directions at the Yoast Mine. The average wind speed at the Seneca IIW Mine is 3.5 knots, <br /> with an average maximum of 15.4 knots, and an average minimum of 17 knots. <br /> Vegetation <br /> All vegetation types within the permit are characterized by cool season species. Five major <br /> vegetation community types occur within the Yoast permit area. These major vegetation <br /> community types are: <br /> o Mountain Brush <br /> o Sagebrush <br /> o Aspen <br /> o Steep Mountain Brush <br /> o Western Wheatgrass/Alkali Sagebrush. <br /> Additional community types occur within the permit area, but are considerably smaller <br /> acreages and include: <br /> o Upland and sub-irrigated improved pasture Mesic drainage <br /> o Lands in the Conservation Reserve Program <br /> o Cropland <br /> o Alkali Sagebrush/Greasewood,and Alkali Meadow. <br /> The majority of soils found within the permit area are suitable for topsoil salvage to a depth of <br /> 0.5 to 3.5 feet. Loams and clay loams are the soil types most commonly found throughout the <br /> permit area. <br /> 6 <br />