2009-05-22_GENERAL DOCUMENTS - C1981044

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within the study area exhibit artesian flows at the surface. The operator conducted aquifer tests to determine the hydraulic properties of the aquifers (see permit application). Bedrock Ground Water Quality. Ground water in the Trout Creek Sandstone and Williams Fork Formation is predominantly calcium and sodium bicarbonate types. Water in contact with coals is a calcium sulfate type and can contain fluoride, iron, manganese, selenium, and sulfate concentrations in excess of U.S. Public Health Service drinking water standards, with the water contained in the coals and thin discontinuous sandstones generally being of poorer quality than that from the massive regional sandstone aquifers. Alluvial Ground Water Occurrence. The Yampa River alluvium and the Williams Fork River alluvium both contain alluvial ground water. These alluvial water-bearing units may store and release water used by the overlying vegetation, and may sustain a component of baseflow to the associated river systems. These alluvial units may provide recharge to rock aquifers and also are recharged by rock aquifers within the ground water study area. Alluvial Ground Water Quality. Alluvial water quality is variable, depending on the underlying rock and source of alluvial material. Ground water from the Yampa River alluvium is primarily sodium sulfate type. Dissolved solids average 4,586 mg/l with a maximum measure of 8,810 mg/l. Ground water for the Williams Fork alluvium is primarily of the sodium bicarbonate type. Total dissolved solids average 1,009 milligrams per liter (mg/1) with a maximum measured value of 1,510 mg/l. Maximum primary and secondary drinking water standards are exceeded in both aquifers for many parameters including barium, cadmium, chloride, chromium, pH, sulfate, and selenium. In addition, average concentration values for chloride, total dissolved solids, iron, lead, manganese, and sulfate exceed EPA primary and secondary standards. Natural Springs and Seeps There are six springs within the permit area and adjacent areas. The North Spring, also referred to as the Lippard No. 1, originates at the head of a small drainage near its junction with old Highway 13 along the base of a thin Pleistocene or Quaternary gravel that caps many terraces in the area. The East Spring flows from the base of a highway fill and appears to be a man-made situation. The South Spring is located on a hillside west of the Williams Fork River approximately one mile south of the No. 5 Mine portal where water discharges from a sandstone lens within the Iles Formation. A small seep is found at the No. 9 Mine face-up. This spring flows only in the spring and dries up in the summer. The Haxton Spring originates in a weathered, brown-gray, very fine-grained sandstone. A pipe has been set in the ground at the spring, but no flow has been observed. Aggregate flow from the springs is less than 20 gpm. The springs that were surveyed do not appear to be discharge zones for any of the regional bedrock aquifers and are not considered significant water sources. Spoil Springs Water seeps from the base of the old Williams Fork Strip Pit No. 1 and drains into the Williams Fork River. Presumably the water percolates through the regraded spoils of the pit. Flow has ranged between 4 gpm and 198 gpm. Total dissolved solids have averaged around 1,000mg/1. Soil Types The permit area is occupied by three soil orders: Aridisols, Entisols, and Mollisols. These soil orders are characteristic of fairly steep, semi-arid regions of northwestern Colorado. They represent soils that grade from recently developed soil bodies with minimum horizon development (Entisols) to older soils with well-defined diagnostic horizons (Mollisols). Eagle Mine Complex 8 Permit Renewal 05 C-1981-044 May 22, 2009