Laserfiche WebLink
RULE 2 PERMITS <br />from Wilson, Goodspring or Taylor Creeks. Instead, the Williams Fork flows into the Yampa River near <br />the town of Hamilton. This location is far above the confluence of 'the Yampa River with Milk Creek, the <br />immediate receiving system of water from Goodspring, Wilson and Taylor Creeks. <br />Surface and groundwater resources in the general area of the mine are limited. There is little development <br />of resources. Those resources which are developed are limited in scope and in quantity. A few wells have <br />been constructed into the fine grain sandstones of the Williams Fork Formation or into fractured parts of <br />the Mancos Shale. These wells typically yield less than five gallons per minute (gpm) and their uses are <br />limited to domestic and/or livestock supplies. Surface water development in the region is limited to <br />irrigation and consists of both direct flow and storage rights. Most of the surface water development <br />occurs in the valley of the Yampa River east of Craig, Colorado. However, this general area of the <br />development is many miles from the mine property. <br />Permit Area <br />Groundwater on the Colowyo Mine property occurs under perched conditions in the interbedded and <br />lenticular sandstones of the Williams Fork Formation above the coals to be mined. There is no <br />continuous, regional groundwater system on the property within the stratigraphic section to be mined. <br />Only below the floodplains of Goodspring Creek are the sandstones fully saturated. The sandstones on the <br />property that store and transmit limited amounts of groundwater above the coals are lenticular and exhibit <br />little lateral continuity. Water stored in these sandstones percolates in a downdip direction by gravity and <br />is discharged to the land surface high in stream cuts as small seeps and springs. The general direction of <br />the groundwater flow on the property is controlled by the geologic structure. No connection between <br />groundwater on the mine property above the mine and surface and groundwater flows in Goodspring and <br />Taylor Creeks has been observed or documented. <br />The lack of a regional groundwater system on the property was documented 111 a report prepared by <br />Leonard Rice Consulting Water Engineers (LRCWE, 1979). That report described an investigation <br />undertaken to determine the impact of mining on the region's water quality. To complete the study, 57 <br />springs and seeps discharging from isolated perched aquifers were located and sampled. The study area <br />included the existing mine faces and pit at the time of mining, and wells and springs that were visited in <br />earlier years. <br />Flows from the springs and seeps were estimated during the site visit. Most of the flows were observed to <br />be less than one or two gpm. The highest spring discharge was estimated to be five gpm. All of the water <br />flow in, or adjacent to, the mine permit area at the time of the study was observed in Goodspring, Taylor, <br />and Wilson Creeks. The springs and seeps occurred at random elevations on the mine permit property and <br />their discharge was consumed by evapotranspiration on the valley sides and on the mine face floor. There <br />was no discharge from the seeps and springs to a natural body of water such as Goodspring or Taylor <br />Creeks. <br />During the investigation for the LRCWE report, the cut made by the Colowyo Mine into the Williams <br />Fork Formation was estimated to be 450 feet deep. The mine face consisted of a series of steps or benches <br />and exposed many interbeds of sandstones and shales. At no time during the excavation or mining <br />processes was an appreciable quantity of water ever encountered by the Colowyo Mine. In parts of the <br />mine face, where the mining process cut into a sandstone containing water, the water drained from the <br />sandstone onto the mine face or into the mine pit. The discharges of water from these seeps were so small <br />that the water was consumed from the face or the floor of the pit by evaporation. This condition has <br />continued to persist over the past twelve years as the mine advances. <br />Rule 2 Permits 2.04.7-2 Revision Date: 6/23/08 <br />Revision No.: MR-91