2019-05-29_GENERAL DOCUMENTS - C1981018

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4 Sandstone. The Williams Fork Formation is further divided into upper and lower members. The Lower Williams Fork Member contains coal bearing seams "A" through "H." The "B" and "D" seams will be recovered at the Deserado Mine. The B seam is presently being mined; the D seam is no longer being mined. The dip of the Mesaverde Group within the permit area is controlled by the asymmetric Red Wash Syncline, which strikes northwest southeast. Dips vary from 7 degrees in the southern part of the permit area, horizontal at the synclinal axis, to as much as 70 degrees on the north flank of the syncline. The coal and sandstone beds outcrop along this steep northern flank. Structure and local topography are the main factors that control ground water movement in the area. The Williams Fork Formation is divided into three hydrologic units: The Sandstone Facies, which underlies the "A" coal seam and is generally equivalent to the Trout Creek Sandstone and the upper portion of the Iles Formation; the Siltstone and Coal Facies, which consists of the interbedded coal, siltstone, and shale strata of the Lower Williams Fork Formation; and the upper Sandstone Facies of the Upper Williams Fork Formation. A fourth hydrologic unit is the alluvium of the White River and its tributaries. The maximum thickness of the White River Alluvium near the permit area was found to be 37 feet. Groundwater in the alluvium occurs in an unconfined condition. No major usage of groundwater in or adjacent to the permit area has been defined by the permittee. Due to the generally low yield and poor quality of aquifers in the region, high groundwater usage would be unusual. Recharge of the bedrock aquifers occurs primarily at higher elevations north of the permit area through infiltration of precipitation in outcrop areas. Discharge is primarily through seeps where aquifers are erosionally exposed along the White River. The operator had originally developed an alluvial well field near the confluence of Scullion Gulch and the White River to supply water for mine operations. In 1984, Kenney Reservoir was completed above Rangely, Colorado. Kenney Reservoir impounds the White River through the southern portion of the permit area, inundating much of the alluvial well field. Because the alluvial surface is almost completely submerged by the reservoir, recharge to the alluvium is now instantaneous. Due to inundation of the well field by the reservoir, and due to high salinity of the alluvial well water, the operator now pumps water directly from the White River into an adjacent lagoon, and from there, water is pumped to the mine’s raw water storage tank. Only one alluvial well, Qal-5, located at the mouth of Scullion Gulch, remains in use as a monitoring well. The Red Wash Syncline and associated major fracture zones located along the Red Wash, Scullion Gulch and the White River control movement of the Mesaverde groundwater. Groundwater in the northwest part of the permit area moves down dip to the Red Wash Syncline. Within the central and southern portion of the permit area, groundwater flows south to the White River. Surface water drainage patterns in the area are incised and dendritic. Scullion Gulch and Red Wash flow primarily in response to direct precipitation. The White River is a perennial stream