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Only small ephemeral drainages cross the site. All surface runoff from disturbed areas is either <br />directed to a sedimentation pond or approved for exemption (small areas) from treatment through <br />a sedimentation pond. <br />Groundwater <br />Hydrogeological field studies, including the establishment of a groundwater monitoring system <br />of the NCIG Permit Area, began in late 1981. These studies included spring and seep surveys, <br />alluvial, colluvial, and bedrock groundwater monitoring, water quality and quantity analyses, <br />aquifer testing, and geologic mapping. <br />Potential water - bearing zones were identified in the Rollins, Middle and Upper Sandstone and <br />the Wheeler Coal. The first three units have been recognized as regional aquifers where the <br />hydrogeologic conditions are suitable. Ground water occurs in both bedrock and alluvial deposits <br />in the vicinity of the proposed mining operation. The potential for groundwater within the area of <br />the mine is greatly limited by the extreme dip of the rock strata which results in prohibitive <br />drilling depths within a short distance. <br />All water from the three sandstone zones is of a sodium - bicarbonate water type. Total dissolved <br />solids range from 575 to 1,340 mg/1. This water type and range of concentrations are very similar <br />to analyses from the same geologic units taken from other locations along this structure and <br />stratigraphy sequence. <br />Climatology <br />The climate is semi -arid with an annual precipitation of 16 inches. Average monthly <br />precipitation varies little throughout the year. Precipitation varies little seasonally, averaging one <br />to two inches per month. Snowfall can reach up to 60 inches in higher elevations. <br />Summers are hot, marked by very low humidity and cool nights. Winters are cold, generally <br />snow -free, but with frequent blizzard conditions. The mine site has a typical alpine climate, <br />experiencing long, cold winters, averaging from low teens at night to 30 degrees Fahrenheit in <br />the day, and moderate summers. "Mountain top" air flow of cold night air drains from the <br />mountain sides down to the Colorado River Valley. Prevailing winds blow from west and <br />northwest to the southeast with an average velocity of 5.3 mph. <br />Soils <br />Soils in the area are characterized as moderately deep to deep, well- drained loams with a dark <br />colored surface layer. Variability in the characteristics of the soil in the area is primarily due to <br />slope and topography. Deeper soils are located in the valley bottoms and at the foot of slopes <br />while the shallower soils occupy the steeper side slopes. <br />Two soil types have been identified at the mine site. These are the Heldt silty clay, found on the <br />lower slopes, and the Nihil stony loam found on the steeper slopes. <br />The Heldt silty clay occurs on alluvial fans and side slopes of the mountain valleys. The clay is <br />fine, slightly montmorillic and is grayish -brown in color. It varies from 10 to 60 inches in depth <br />Coal Ridge No. 1 Mine <br />Permit Renewal 6 6 31 October 2011 <br />