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described in the Permit. Ash importation ceased in April 2016. During active surface coal <br />extraction, the Number 7 seam of the Laramie formation was mined. <br />3.2.4 Geology, Soils and Topography <br />The permit area is located on level to gently rolling topography consisting of fine sand, which is <br />wind -deposited material overlying weathered residual shale. The sand varies in depth from <br />about 5 feet to 20 feet, is highly to moderately permeable, and is highly susceptible to wind <br />erosion. The flat -lying Number 7 coal seam was overlain by 60-180 feet of overburden <br />consisting of yellow-brown and gray to blue gray soft carbonaceous shale and clay interbedded <br />with sandstone and shaley sandstone. At the base of the Laramie formation is the Fox Hills <br />member, a cross -bedded gray to buff sandstone, which is slightly or well cemented. <br />3.2.5 Surface and Ground Water <br />Because of the low relief and deep, well -drained soils, there is virtually no surface runoff. No <br />streams, springs or seeps exist in the area. All water flows subsurface through aeolian deposits <br />to Ennis Draw, a topographic swale (ephemeral drainage) located along the eastern boundary of <br />the permit area. Ennis Draw appears to be a complex, braided, ancient stream bed that has been <br />covered by windblown sand. The draw discharges several miles to the north into Box Elder <br />Creek. <br />Ground water moves laterally toward the northeast, and apparently discharges into the sands and <br />stream deposits in Ennis Draw. <br />At the time the mine was originally permitted, ground water in neither the coal nor overburden <br />was known to provide a water supply for any purpose in the vicinity of the mine. Since that <br />time, ground water is being drawn for industrial uses at the mine, and a number of other wells <br />have been drilled in the vicinity of the mine (review of State Engineer Records). However, no <br />adverse impact from the mine is expected, due to the geologic and hydrologic conditions of the <br />site. <br />3.2.6 Climate <br />The Keenesburg mine site is situated in an area which has a "continental" type of climate, <br />characterized by low relative humidity, a large amount of sunshine, light rainfall, moderately <br />high winds, and large daily range in temperature. The average annual mean temperature is 48.4° <br />F. The average precipitation over 32 years was 13.11 inches, as measured at the mine site. For <br />the years 2003 through 2016, average annual precipitation ranged from 9.89 to 18.13 inches. <br />3.2.7 Vegetation, Wildlife and Land Use <br />0 <br />