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The Dakota coal aquifers and the overburden aquifer in the New Horizon 2 mining area yielded <br />groundwaterthatexceededoneormoreofthelivestockdrinkingwaterstandards. The coal aquifer <br />in the New Horizon 2 mining area has poor quality with regard to agricultural water use. <br />A comparison of TDS values for the New Horizon wells indicates that 3 wells exceeded the 5,000 <br />mg/I limit, 12 wells yield water that could only be used for tolerant plants on permeable soils with <br />careful management practices, and 2 wells yielded waterthatmight have adverse effects on crops <br />and requires careful management practices. Shallow ground water aquifers at New Horizon were <br />unsuitable for irrigation use. Plots of SAR's versus conductivity for each of the wells showed that <br />the ground waterfell into one oftwo categories. Itwas either a high to very high salinity hazard and <br />a low sodium hazard (12wells) ora high to very high salinity hazard and a very high sodium hazard <br />(2 wells). <br />Wells yields and aquifercharacteristics ofthe shallow aquifers atthe New Horizon Mine were also <br />considered when evaluating potential water uses. Transmissivity values ranged from 77 to 1.1 <br />ft2/day and pumping rates above 1.5gpm could notbe maintained forany significant period of time. <br />Where short term, pumping withdrawal tests (McWhorter's analyses) were performed specific <br />capacities ofonly 0.1 to 0.6 gpm/ft could only be maintained overshorttime periods. Aquiferyields <br />were too low for irrigation purposes and only poor to fair for domestic purposes. Assuming yields <br />necessary for livestock water would be similar to domestic needs, the aquifer yield potential for <br />livestock use was also fair to poor. <br />In conclusion, the shallow aquifer chemistry atthe New Horizon Mine is unsuitable fordomestic and <br />irrigation purposes. Only the New Horizon 1 overburden, the underburden aquifer at both mining <br />areas and the spoils and alluvial aquifers appear to be chemically suitable for use as livestock water. <br />Aquiferyields are too low for irrigation use and can only be considered marginal to poorfordomestic <br />or livestock uses. Considering the combined criteria, only certain aquifers (underburden, spoils and <br />alluvium) would be marginally suitable for use as livestock drinking water. <br />REGIONAL SURFACE WATER CHARACTERISTICS <br />The New Horizon 1 and New Horizon 2 mining areas are drained by Tuttle and Calamity Draws, <br />respectively. Both draws are perennial tributaries of the San Miguel River which in turn flows into <br />(REVISED 6/28/01) 2.04.7-19 <br />