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Probable Hydrologic Consequences <br />Ground Water <br />1. Interruption of ground water flow and <br />drawdowns <br />SUMMARY <br />2. Removal of wells and ponds by mining. <br />3. Impact of replaced spoil material on ground <br />water flow and recharge capacity. <br />4. Containment of pit inflow pumpage and <br />impacts on water quality. <br />TABLE 2.05.6.(3) -2a <br />OF CONSEQUENCES OF THE UFE-OF -MINE MINING PLAN <br />FOR THE NEW HORIZON NORTH MINING AREA <br />Analysis Results Significance <br />Maximum projected pit inflow rates will be <br />approximately 3840 ft /day during year 1 of mining at <br />the New Horizon North mining area. The maximum <br />extent of the 1 foot drawdown contour is estimated to <br />be about 760 feet from any point in the pit <br />Two water righted wells (Well Permits #253229 and <br />#163178) will be mined through, (see Table 2.04.7 -4 <br />and Map 2.04.7 -8). The Meehan Well is under an <br />option to purchase and the Glassier Land is under <br />lease. Both of these wells are Morrison Fm. wells and <br />will be plugged appropriately prior to mining. <br />Horizontal hydraulic conductivities will be higher in the <br />spoil as a result of higher percentages of <br />interconnected porosities. Existing and reclaimed <br />topsoil infiltration rates are similar except for some <br />loss of soil structure in the reclaimed topsoil. Vertical <br />hydraulic conductivities in the overburden are <br />principally limited to interconnected fractures. Flow <br />impeding ledges of consolidated rock are absent in <br />the spoil but there is poorer sorting of grain sizes. <br />Only one exceedence of an NPDES standard has <br />occurred as a result of pond discharges since 1979. <br />Pit pumpage impacts to San Miguel water quality are <br />projected at an .08 percent increases in TDS. <br />Short term impact of minimal significance. Any injury to <br />surface water rights will be mitigated according to the <br />surface water augmentation plan. Wells proximate to <br />mining areas are completed in deeper units and are not <br />likely to be injured (little significance). Ground water <br />rights mitigation plan addresses alternative ground or <br />surface water sources should they be needed. No <br />short or long term significant impacts. <br />No impact. <br />Short term impact to topsoil structure but of little <br />significance as far as infiltration rate changes because <br />of plowing and disking practices in the reclamation. <br />Vertical hydraulic conductivities in the spoil will improve <br />because they are no longer dependent on fracture flow. <br />Horizontal hydraulic conductivities should also be <br />higher. However, structural attitude will result in <br />draining of the backfill with relatively little saturation. <br />There is very little chance of federal or state receiving <br />stream water quality standards being exceeded in any <br />pond discharges. If any problem were to occur, the <br />discharge could be stopped from the pond and the <br />problem could be remediated. Pit pumpage impacts in <br />terms of TDS increases in Calamity Draw and the San <br />Miguel River will be very slight No short or long term <br />significant impacts affect water rights downstream. <br />