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1) Alluvium: These Quaternary deposits include all sediments associated directly with the active <br />portions of the various stream channels and alluvial fans. <br />2) Terraces: Sediments associated with the inactive portions of the stream channels, particularly <br />those at much higher levels, have been categorized as Quaternary Terraces. <br />3) Colluvium: Colluvial deposits are considered to be loose, heterogeneous rock masses composedof <br />soils and rock fragments which have been deposited chiefly by mass -wasting, usually at the base <br />of steep slopes. <br />Surface Water <br />The Coal Ridge No. 1 Mine permit area is located in the Upper Colorado River Basin, in portions of <br />three watersheds: the Colorado River, Alkali Creek, and South Canyon Creek. Proposed mining <br />operations beneath portions of the Alkali and South Canyon Creek watersheds did not occur. <br />Water from the Colorado River is of good quality and is used for domestic and irrigation purposes. <br />Salinity concerns have resulted in the establishment of standards for the upper and lower Colorado <br />River basin (including the Colorado River and Alkali Creek). Water has been monitored since 1981 on <br />Alkali Creek and 1983 on the Colorado River. The Colorado Department of Public Health and <br />Environment receiving stream standards for some metals have occasionally been exceeded in both the <br />Colorado River and Alkali Creek, but the elevated metals were not determined to be mine related. See <br />PAP pages 3-40 through 3-49 for more information on surface hydrology. <br />Only small ephemeral drainages cross the site. All surface runoff from disturbed areas used to be <br />either directed to a sedimentation pond or approved for exemption (small areas) from treatment <br />through a sedimentation pond. In the fall for 2015 Sediment Pond A (the last remaining pond on the <br />site) was reclaimed. A NPDES Stormwater Permit was issued for the Coal Ridge Mine, see Part <br />H. 2. On page 14 of this document for more details. <br />Groundwater <br />Hydrogeological field studies, including the establishment of a groundwater monitoring system of the <br />Coal Ridge Permit Area, began in late 1981. These studies included spring and seep surveys, alluvial, <br />colluvial, and bedrock groundwater monitoring, water quality and quantity analyses, aquifer testing, and <br />geologic mapping. <br />Potential water -bearing zones were identified in the Rollins, Middle and Upper Sandstone and the <br />Wheeler Coal. The first three units have been recognized as regional aquifers where the hydrogeologic <br />conditions are suitable. Ground water occurs in both bedrock and alluvial deposits in the vicinity of the <br />proposed mining operation. The potential for groundwater within the area of the mine is greatly limited <br />by the extreme dip of the rock strata which results in prohibitive drilling depths within a short distance. <br />All water from the three sandstone zones is of a sodium -bicarbonate water type. Total dissolved solids <br />range from 575 to 1,340 mg/l. This water type and range of concentrations are very similar to analyses <br />Coal Ridge Mine <br />Permit Renewal No. 7 6 December 5, 2016 <br />