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Ground Water Quantity <br />Typical backfilling methods largely involve the use of dozers and trucks (see Section 2.05.4(2)(c), <br />Backfilling and Grading). Replaced spoil materials exhibit greater porosities and hydraulic <br />conductivities because of increased void values, regardless of how the spoil material is replaced <br />in the pits. <br />Spoil replacement (backfilling) using methods outlined in Section 2.05.4(2)(c), Backfilling and <br />Grading, will ensure the eventual resaturation of the disturbed areas (pits), minimizing the adverse <br />effects of mining on ground water flow. The New Horizon 2 mining area is located in a climate <br />which generates less than 15 inches of precipitation annually. Evapotranspiration rates in the <br />vicinity are relatively high (see Section 2.04.7, Hydrology Description). Textural analyses performed <br />on potential spoil materials generally indicates that sandy clay loam materials will be replaced in <br />the pits (see Section 2.04.6, Geology Description). Consequently, infiltration rates in reclaimed <br />areas are expected to be slow to moderate. It follows that contributions to spoil resaturation and <br />subsequent recharge to surrounding aquifers from precipitation will be slow. However, the upland <br />and adjacent irrigation ditches and laterals will eventually provide a more rapid source of recharge <br />to spoils. Seepage from the irrigation network has provided an artificial source of recharge to the <br />undisturbed shallow ground water system. The resaturation and recharge of replaced spoils will <br />also be augmented by the irrigation. This is discussed in more detail in sub - section 6.0. <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 />for establishing reclaimed areas that will exhibit infiltration rates and capacities adequate for <br />insuring at least pre- mining 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 water to 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 />Revised September 2014 JR -64) 2.05.6(3) -6 <br />