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Site Descriptions <br />Surface Water Table 15-2, Summary of Surface Water Monitoring Sites, Yoast Mine, provides a <br />description of all historic and current surface water and spring monitoring sites. <br />Ground Water Table 15.3, Summary of Ground Water Monitoring Sites, Yoast Mine, provides a <br />summary of all historic and current ground water monitoring sites. Wells with USGS numbers on <br />Table 15-3, Summary of around Water Monitoring Sites, Yoast Mine, were drilled and completed in <br />the summer of 1980 by the USGS. 411 remaining wells were drilled and completed in the summer of <br />1990 by PWCC. Well construction summaries and lithologic logs are found in Appendix 7-1, Well <br />~. Completion Summaries, Well Construction Diagrams, and Lithologic logs. <br />'I Development procedures for the 1980 USGS wells were not documented. However, the act of <br />purging water for water quality samp~ing will have developed these wells by the removal of sediment <br />in the well casing, screen, and gravel pack. Development procedures for the 1990 PWCC wells <br />consisted of air surging, bailing, and/or pumping. <br />• <br />Aquifer tests were performed on most wells completed in 1990 and also for selected USGS wells Isee <br />i Table 7-9, Site Specific Aquifer Characteristics for Yoast Minel. Aquifer tests were not performied on • <br />Wells YOV29 and YWCU31 due to a lack of water. Aquifer test data is discussed in Tab 7, <br />Hydrologic Description and is presented in Appendix 7.3, Aqufer Test Data. <br />Monitoring Frequencies <br />The current monitoring program was established after a review of the hydrologic data presented in the <br />Hydrologic Description (Tab 7, Hydrologic Description) and the Probable Hydrologic Consequences <br />ITab 17, Probable Hydrologic Consequencesl. Data in those two tabs indicated that mining will have <br />little impact on water-bearing bedrock strata (i. e.. Wadge coal, overburden, and underburdenl do~xndip <br />of mining. These bedrock sVata typically have poor water quality and yields. Also, better aquifers ~ <br />II li.e., the Twentymile and 1-rout Creek Sandstones) exist both above and below the Wadge coal (see ' <br />I, Geologic Description in Tab 6, Geology and Overburden Assessmenth and will remain undisturbed for <br />i potential future use. More significant will be the impacts on the alluvial aquifers and streams, and <br />i therefore, monitoring of those systems will be emphasized. <br />CJ <br />20 Revised 2,'99 <br />