2014-05-12_PERMIT FILE - C2010089 (5)

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Water in the surrounding undisturbed ground water system exhibits a relatively high degree of mineralization, (see Section 2.04.7, Hydrology Description). Well yields are low. Recharge to the local undisturbed ground water system is directly from both the 2nd Park Lateral irrigation ditch (and associated laterals) and excess irrigation water runoff from flood irrigation. The irrigation ditch water and runoff infiltrate and percolate into the weathered zone of the bedrock. Prior to mining at NHN, the 2nd Park Lateral ditch will be diverted through a HDPE pipeline in order to prevent disrupting water delivery to down stream 2 "d Park Lateral shareholders. The diversion of the 2nd Park lateral will also result in a "drying up" of the overburden zone prior to mining which will reduce water inflows into the pit. After mining, backfilling, and reclamation has advanced far enough north, the HDPE diversion pipeline will be moved to the original 2nd Park Lateral right -of -way. The structural attitude of the strata, strike northwest — dip southwest, (see Section 2.04.6 Geology Description), will result in post mine irrigation water percolating through the backfill material and migrating to the south along the top of the under - burden (path of least resistance) to the toe of backfill where it will issue as springs tributary to Tuttle Draw (area south of Meehan Draw) and as springs tributary to Meehan Draw (area north of Meehan Draw) as shown in Figure 2.05.6(3) -1 presented later in this Section. This situation is illustrated by the effects of the old Peabody Nucla Mine (see Section 2.04.7 Hydrology Description). Due to the self draining effect resulting from the structural attitude only relatively small areas (rolls in the floor of the LDx Seam, etc.) of backfill material may be partially saturated. The springs issuing from the toe of the old Nucla Mine (SS #1 and SS #2, see New Horizon 1 permit) backfill material have a calcium magnesium sulfate type water quality with an average TDS of about 3,650 and average pH of about 7.0. The normal mixing that takes place as overburden is shot, loaded and placed in the backfill and the overall high degree of neutralization potential of the spoil material will minimize changes in ground water quality. See following discussion on Probable Hydrologic Consequences. Based on the mining experience at the adjacent New Horizon Mine, the physical character of the overburden, and the chemical analyses performed on samples taken from the lithologic units to be affected by mining (see Section 2.04.6, Geology Description), the backfill material is classified as either suitable or non - suitable. The weathered bedrock which is located immediately below the soil horizons (referred to as suitable or free dig material) has been oxidized and is both physically and chemically altered from the parent bedrock. The physical alteration of weathering, (to depths of 25 or 30 ft.), weakens the original bed rock material to the point that it can be loaded directly into trucks (free dig material) without the time and expense of drilling and blasting it. This weathered overburden material is typically light brown in color and sharply contrasts with the underlying un- weathered much stronger light gray siltstones and sandstones to the gray and dark brown to black shale and carbonaceous shale. The un- weathered material is referred to as un- suitable material. The suitable and un- suitable material is handled separately at New Horizon Mine and this method is planned for NHN Mine. The un- weathered or un- suitable material is blast casted and dozer pushed across and into the bottom of the pit. The weathered suitable material is loaded and hauled around the ends of the pit and is placed on the unsuitable material as a cap, (see Sections 2.05.4(2)(c) Backfilling and Grading and Section 2.05.6(3) Page 2 November 2011