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minimizing the adverse effects of mining on ground water flow. The New Horizon 2 mining area is <br />located in a climate which generates less than 15 inches of precipitation annually. <br />Evapotranspiration rates in the vicinity are relatively high (see Section 2.04.7, Hydrology <br />Description). Textural analyses performed on potential spoil materials generally indicates that <br />sandy clay loam materials will be replaced in the pits (see Section 2.04.6, Geology Description). <br />Consequently, infiltration rates in reclaimed areas are expected to be slow to moderate, It follows <br />that contributions to spoil resaturation and subsequent recharge to surrounding aquifers from <br />precipitation will be slow. However, the upland and adjacent irrigation ditches and laterals will <br />eventually provide a more rapid source of recharge to spoils. Seepage from the irrigation network <br />has provided an artificial source of recharge to the undisturbed shallow ground water system. The <br />resaturation and recharge of replaced spoils will also be augmented by the irrigation. This is <br />discussed in more detail <br />Overburden and topsoil handling, reconditioning, and revegetation methods outlined in Sections <br />2.05.4(Z)(d), Topsoil (Redistribution), and 2.05.4(Z)(e), Revegetation,) will maximize the potential <br />for establishing reclaimed areas that will exhibit infiltration rates and capacities adequate for <br />insuring at least premining rates and capacities. Timely reseeding and mulching of redistributed <br />topsoil will augment the retention and eventual downward infiltration of soil moisture. Textures of <br />topsoil material will generally range from sandy loam to loam, and topsoil material will exhibit <br />• moderate infiltration rates. Deep ripping of regraded spoil, followed by topsoil placement, chisel <br />plowing, and 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 <br />prescribed volume for the 10-year, 24-hour storm. Design criteria for all ponds is addressed in <br />Section 2.05.3(3), Mine Facilities, and includes plans for storage of additional volumes pumped <br />from pits or sumps. Maintenance of available storage capacity in the ponds involves dewatering <br />and sediment 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 />Horizon 2 mining areas. The current ground water monitoring plan employed to monitor the extent <br />and magnitude of any mining impacts is also discussed in Sections 2.04.7 and Section 2.05.6(3)(V), <br />Hydrologic Reclamation Plan. The ground water monitoring wells will be maintained for the life of <br />the mining operations or until such time as the CDMG may agree that they are no longer necessary. <br />. (REVISED 6/01) 2. X5.6 (3) - 4 <br />