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is believed .that the spoil in the New Horizon #2 Mine area will remain relatively dry until <br />irrigation is resumed from the West Lateral Ditch. Once this irrigation is resumed, recharge <br />will rapidly infiltrate into the spoil, move to the southwest according to the basal gradient and <br />develop a spring at the low point of the lowwall crest, as was experienced at the New Horizon #1 <br />Mine. This point can be seen on Map 2.04.7-1A, near the northwest corner of the permit area near <br />Tuttle Draw. This point was calculated in CAD using the entire excavated area for the mine <br />compared to the surface topography. If any spring develops here, it would discharge into Tuttle <br />Draw. The Morgan property should not experience any spoil springs. <br />Although a large diameter HDPE pipe will be used to carry the ditch water through the permit area, <br />infiltration will begin when the permanent HDPE pipe will be used in re-establishing irrigation in <br />the reclaimed area. This will occur in 2003 for the area east of 2700 Road and will occur after 2010 <br />for the remainder of the mine area west of 2700 Road. It is estimated that full irrigation of <br />the reclaimed area will take place by year 2013. Although the pipe will be used to carry the ditch <br />flow until the end of its useful life in 30-50 years, its use is not relevant to the prediction of <br />irrigation recharge since this recharge will occur over 99% of the area even when the permanent <br />pipe is in place. <br />From soil information, knowledge of the irrigation practices, discussions with USGS, and the rainfall <br />date for the site, the following recharge data has been calculated: 2" from rain and snowmelt, 13" <br />from irrigation and I" from underburden recharge and overburden recharge at the uphill <br />spoil/overburden contact. Total long-term recharge is therefore 16" per year. These predictions are <br />approximate but suffice in predicting the behavior of the groundwater in the spoil. <br />The total affected area is roughly 768 acres. The volume of the reclaim spoil to be recharged below <br />the 5580 spoil spring elevation equals 2,778 ac.ft. as determined from D.T.M. modeling of the spoil <br />area and the pit bottom. Spoil porosity of 15% is determined for the overburden. This yields a pore <br />volume of (0.15)(2778 ac.ft.) = 416 ac.ft. <br />Worst Case Discharge <br />With a pore volume of 416 ac.ft. and assuming a total recharge of 16" per year from all sources <br />over the 768 acres of spoil, annual recharge equals (16/12)(768) = 1024 ac.ft. per year after full <br />irrigation in 2013. It should be noted that a portion of the reclaimed area will be restored to dry land <br />pasture and will therefore will not contribute irrigation recharge, however, other areas will have a <br />greater recharge than 16" total, therefore, the average of 16" over the reclaimed area is <br />reasonable. From the year 2003 to 2013, the expected recharge should only be 10% of this <br />amount, since irrigation will not be used on the majority of the area and the fresh -placed spoil will <br />be relatively dry. <br />Spoil spring discharge = (Spoil Spring Recharge) — (Seepage into Low Wall) <br />July 2016 (TR -74) 2.05.6(3)-16 <br />