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RULE 2 PERMITS <br /> =r mss.. :•:.:: ,..•,,.,•„...,..:.........:..r�r:, ••«f rsa-.a .r.w. <br /> a!+`kw�rv`A=,?�.'N'a+ R',''diPbao.eN`A`.'�.a&:'M'd'£a,•,,.,i\ekk�P«Y..'tt:..o'p.a.aR9.}#•>"�.`.�'"R.E'#..4i a5ck'7'AFN!l}. ..., <br /> mined. Only below the floodplains of Goodspring Creek are the sandstones fully saturated. The <br /> sandstones on the property that store and transmit limited amounts of groundwater above the coals <br /> are lenticular and exhibit little lateral continuity. Water stored in these sandstones percolates in a <br /> downdip direction by gravity and is discharged to the land surface high in stream cuts as small <br /> seeps and springs. The general direction of the groundwater flow on the property is controlled by <br /> the geologic structure. No connection between groundwater on the mine property above the mine <br /> and surface and groundwater flows in Goodspring and Taylor Creeks has been observed or <br /> documented. <br /> The lack of a regional groundwater system on the property was documented in a report prepared <br /> by Leonard Rice Consulting Water Engineers (LRCWE, 1979). That report described an <br /> investigation undertaken to determine the impact of mining on the region's water quality. To <br /> complete the study, 57 springs and seeps discharging from isolated perched aquifers were located <br /> and sampled. The study area included the existing mine faces and pit at the time of mining, and <br /> wells and springs that were visited in earlier years. <br /> Flows from the springs and seeps were estimated during the site visit. Most of the flows were <br /> observed to be less than one or two gpm. The highest spring discharge was estimated to be five <br /> gpm. All of the water flow in, or adjacent to, the mine permit area at the time of the study was <br /> observed in Goodspring, Taylor, and Wilson Creeks. The springs and seeps occurred at random <br /> elevations on the mine permit property and their discharge was consumed by evapotranspiration <br /> on the valley sides and on the mine face floor. There was no discharge from the seeps and springs <br /> to a natural body of water such as Goodspring or Taylor Creeks. <br /> During the investigation for the LRCWE report, the cut made by the Colowyo Mine into the <br /> Williams Fork Formation was estimated to be 450 feet deep. The mine face consisted of a series <br /> of steps or benches and exposed many interbeds of sandstones and shales. At no time during the <br /> excavation or mining processes was an appreciable quantity of water ever encountered by the <br /> Colowyo Mine. In parts of the mine face,where the mining process cut into a sandstone containing <br /> water,the water drained from the sandstone onto the mine face or into the mine pit. The discharges <br /> of water from these seeps were so small that the water was consumed from the face or the floor of <br /> the pit by evaporation. This condition has continued to persist over the past twelve years as the <br /> mine advances. <br /> The 1979 LRCWE report documented the absence of groundwater on the property. This report is <br /> attached in Exhibit 7, Item 1. <br /> Whereas most of the sandstones on the Colowyo Coal Company property are lenticular and <br /> interbedded with shales,the Trout Creek Sandstone is a regional geologic unit that can be mapped <br /> across the mine property and regionally. This sandstone occurs approximately 800 feet beneath <br /> the lowestmost coals to be surface mined. It is exposed to the surface north of the mine property <br /> because of the uplift in the Axial Basin. The sandstone is 75 feet thick and consists of white, fine- <br /> grained and well sorted sand, cemented with calcareous materials. The sandstone is relatively <br /> uniform across the area and can be correlated throughout most of northwestern Colorado. <br /> Rule 2 Permits 2.04-13 Revision Date: 12/20/19 <br /> Revision No.: TR-135 <br />