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Section 2.04.7 <br />Hydrology Description <br />New Horizon 1 and 2 Mine is the old Peabody Coal Company Nucla and Nucla East Mine which operated <br />under the same permit number. Peabody performed detailed hydrologic studies at the New Horizon I and <br />2 mine areas (formerly called the Nucla and Nucla East mine areas respectively). New Horizon refers the <br />reader to the original Peabody permit application: Volumes D, E, F, and G for hydrology data related to <br />New Horizon I (NHI) Mine. Much of the NHI area, as defined by discussion in this section, has been <br />freed from the permit due to final bond release in 2002. Therefore, the discussion below will refer to areas <br />both within and outside the permit. <br />Site Specific Ground Water Information and Baseline Data <br />Introduction <br />Regional and site specific geology and physiography pertinent to the discussion of ground water resources <br />at the New Horizon 2 area are discussed in Section 2.04.6. Maps 2.04.6-2 through 2.04.6-6 (Geologic <br />Cross Sections A -A' through H -H') graphically illustrate the site specific geology at the New Horizon 1 <br />and 2 mining areas. In order to locate the monitoring wells cited in the following discussion, please refer <br />to Map 2.04.7-1A. <br />Baseline Ground Water Levels <br />New Horizon maintained and operated a ground water monitoring network at the New Horizon 1 and 2 <br />mining areas that consisted of 35 monitor wells. Each monitor well was measured for static water level on <br />a monthly basis. Some of these wells are still being monitored under the currently approved hydrological <br />monitoring program. <br />The wells at New Horizon 1 (GW -N1, GW-N1P1, GW -N3, GW -N4, GW -N5, GW -N6, GW -N8, GW -N9 <br />and GW -N11) were monitored since September of 1979. Monitor Well GW-NIO was measured for water <br />levels since January of 1981. Three additional spoil wells (GW -N26, GW -N27 and GW -N28) and one <br />replacement coal well (GW-N4R) were installed in August and September, 1987. Measurements for static <br />water levels began at these wells immediately after they were completed and developed. <br />In order to obtain specific baseline water level information at New Horizon 2 a total of 22 monitor wells <br />were drilled and completed. In June of 1986,16 monitor wells (GW -N13, GW -N14, GW -N15, GW -N16, <br />GW-N16PI, GW -N17, GW-N17P1, GW -N18, GW-N18P1, GW -N19, GW -N20, GW -N21, GW -N22, <br />GW -N23, GW -N24 and GW -N25) were installed. During August and September of 1987, six additional <br />monitor wells were installed, (GW -N29, GW -N30, GW -N31, GW -N32, GW -N33 and GW -N34). <br />Measurements for static water levels began at these wells immediately after they were completed and <br />developed. All of the water level data are presented in tabular and graphic form in Appendix D of <br />Attachment 2.04.7-5 Hydrological Monitoring Plan. Five more wells (GW -N36, GW -N37, GW -N38, <br />GW -N39 and GW -N40) were added in May 1993. The first three wells were drilled in the north-east <br />corner of the permit area. The last two wells were drilled along the Calamity Draw. <br />Page 2.04.7-3 March 2017 JR -77) <br />