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in the pits. Spoil replacement (backfilling) using methods outlined in Section 2.05.4(2)(c), Backfilling <br />and Grading, will ensure the eventual resaturation of the disturbed areas (pits), minimizing the <br />adverse effects of mining on ground water flow. The New Horizon 2 mining area is located in a <br />climate which generates less than 15 inches of precipitation annually. Evapotranspiration rates in <br />the vicinity are relatively high (see Section 2.04.7, Hydrology Description). Textural analyses <br />performed on potential spoil materials generally indicates that sandy clay loam materials will be <br />replaced in the pits (see Section 2.04.6, Geology Description). Consequently, infiltration rates in <br />reclaimed areas are expected to be slow to moderate. It follows that contributions to spoil <br />resaturation and subsequent recharge to surrounding aquifers from precipitation will be slow. <br />However, the upland and adjacent irrigation ditches and laterals will eventually provide a more rapid <br />source of recharge to spoils. Seepage from the irrigation network has provided an artificial source <br />of recharge to the undisturbed shallow ground water system. The resaturation and recharge of <br />replaced spoils will also be augmented by the irrigation. This is discussed in more detail <br />Overburden and topsoil handling, reconditioning, and revegetation methods outlined in Sections <br />2.05.4(2)(d), Topsoil (Redistribution), and 2.05.4(2)(e), Revegetation,) will maximize the potential <br />forestablishingreelaimed areas thatwill exhibit infiltration rates and capacities adequate forinsuring <br />at least premining rates and capacities. Timely reseeding and mulching of redistributed topsoil will <br />augment the retention and eventual downward infiltration of soil moisture. Textures of topsoil <br />material will generally range from sandy loam to loam, and topsoil material will exhibit moderate <br />infiltration rates. Deep ripping of regraded spoil, followed by topsoil placement, chisel plowing, and <br />disking will improve the infiltration potential of the reclaimed medium. <br />Significant ground water inflow to the pits will be removed by pumping the waterto a sediment pond <br />that will, at the time of pumping, have a sufficient available storage capacity, including the prescribed <br />volume for the 10-year, 24-hour storm. Design criteria for all ponds is addressed in Section <br />2.05.3(3), Mine Facilities, and includes plans forstorage ofadditional volumes pumped from pits or <br />sumps. Maintenance of available storage capacityinthepondsinvolvesdewateringandsediment <br />removal. <br />Ground Water Monitoring <br />Since 1979, Peabody (New Horizon Mine's predecessor) progressively installed an extensive <br />network of 35 wells to monitor the shallow aquifers beneath both the New Horizon 1 and the New <br />Horizon2miningareas. Thecurrentgroundwatermonitoringplanemployedtomonitortheextent <br />and magnitude ofany mining impacts is also discussed in Sections 2.04.7 and Section 2.05.6(3)0, <br />Hydrologic Reclamation Plan. The ground water monitoring wells will be maintained forthe life of <br />(REVISED 6/01) 2.05.6 (3) - 9 <br />