2013-04-05_PERMIT FILE - C1996083A (20)

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2.04.7 Hydrology Description • (1)(a)(i)(ii)(iii) and (iv) Method of study: To establish baseline data, 13 drill holes were converted into monitoring wells during the 1982 and 1983 exploration drilling campaign. After drilling, each hole was cased with 4 -inch P.V.C., flush joint pipe from the surface to perforated pipe which was located within the strata where data was desired. See monitoring hole completion drawings for details on each hole completed presented in Volume III, Exhibit 3. Of the 13 holes completed, 5 were completed in the overburden above the "D" Seam, 5 in the "D" seam, one in the overburden above the "B" Seam, 1 in the Rollins Sandstone formation and 1 in alluvium. The aerial extent of the groundwater investigation is generally bounded by Stevens Gulch Creek on the West, Hubbard Creek on the East, and the North Fork of the Gunnison River on the South, comprising approximately 8500 acres. For actual monitoring locations see Map 9, Hydrologic Monitoring Location. The groundwater study was initiated by Coors Energy Corporation in the Spring of 1982. This investigation produced a preliminary map showing hydrologic feature locations and monitoring data for these features during • 1982 and 1983. In the spring of 1995 the preliminary map was used by the Operator to locate the existing hydrologic features and monitoring was resumed after the features were substantiated in the field. During the fall of 1997 the Operator's technical staff examined the surrounding area and identified numerous additional ponds and springs. The Operator believes these field programs were comprehensive and thorough in terms of assessing the surficial hydrologic regime of the entire permit area and the field data obtained and compiled to be accurate and reproducible, within acceptable limits. Hydrologic investigations of the western mining district began in the spring, 1983 by a previous operator of the Bowie No. 1 Mine. Color air photographs purchased from Associated Surveys (which performed the flyovers on September 22, 1982, under CMLRD contract) at a scale of 1 inch to approximately 1,000 feet were inspected for vegetative and geomorphologic indicators. Concurrently, a suitable base map depicting topography, roads, structures, etc., was enlarged to 1:12000 from U.S.G.S. 7 1/2 minute series and compiled. A preliminary map was developed in which the possibility of a hydrologic feature was to be substantiated in the field. In this fashion, every likely site for a pond, spring, etc., was identified. Subsequently, in order to verify the correct locations, search for additional features, characterize field • parameters (flow pH, temperature, and conductivity) , and ascertain beneficial use, the Operators technical staff examined the area of study on foot, where surface ownership consent was obtained. Some of the features PR -12 2.04-28- 06/10 A ppRovE/� t1/4 /jo