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1. The applicant will conduct monitoring of ground water in a manner <br /> approved by the Division. The ground water monitoring plan is listed <br /> in Tables l and 3 of this document. (4.05.l3(1)). <br /> 2. The applicant will conduct monitoring of surface water in a manner <br /> approved by the Division. The monitoring plan was submitted under <br /> 2.05.6(3)(b)(iv) and is listed in Tables 2 and 4 of this document. <br /> (4.05.13(2)). <br /> F. Probable Hydrologic Consequences <br /> Probable hydrologic consequences of the proposed Yoast mining operations <br /> are discussed in Tab 17 of the permit application package. A summary of that <br /> discussion is presented here. <br /> Groundwater <br /> The probable hydrologic consequences to groundwater resulting from coal <br /> extraction at the Yoast Mine include drawdowns to aquifers from pit inflows, <br /> and subsequent pit dewatering and production well pumping as well as <br /> impacts to groundwater quality resulting from flow through mine spoil. <br /> Seneca's predictions of the magnitude of these impacts are discussed below. <br /> Groundwater Inflows to Pits and Associated Drawdowns <br /> The Yoast Mine will intercept the following hydrologic units: the Wadge <br /> Overburden, Wadge Coal, Wolf Creek Overburden, and Wolf Creek Coal. <br /> Seneca Coal Company used two models to predict pit inflows as a result of <br /> mining activities. The models were the McWhorter(1982) method and the <br /> Theis equation, both of which are described in detail in Tab 17 of the PAP. <br /> The Theis equation, which was also used to predict drawdowns, consistently <br /> predicted higher discharges for each aquifer with the exception of the Wolf <br /> Creek Coal than did the McWhorter method. <br /> The more conservative estimates of pit inflows from each aquifer in cubic <br /> feet per day are 365 for the Wadge Overburden, 160 for the Wadge Coal, 745 <br /> for the Wolf Creek Overburden, and 499 for the Wolf Creek Coal. Variability <br /> in aquifer characteristics in the Grassy Creek and Sage Creek drainages cause <br /> variation in the predicted drawdowns. The radial distance to a one foot <br /> drawdown in the Wadge Overburden was predicted to be 401 feet in the <br /> Grassy Creek drainage and 564 feet in the Sage Creek drainage. The one foot <br /> drawdown radius in the Wadge Coal was predicted to be 369 feet in the <br /> Grassy Creek drainage and 468 feet in the Sage Creek drainage. Radial <br /> distances to the one foot drawdowns in the Wolf Creek Overburden and Wolf <br /> Creek Coal in the Sage Creek drainage were predicted to be 452 and 491 <br /> Ymt Mine 74 October 19, 1999 <br />