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2.04.7 (1) (z) <br />Figures 2.04.5-2, 2.04.5-2a, 2.04.5-3, 2.04.5-3a, 2.04.5-4, 2.04.5-4a, 2.06.5-5, and <br />2.04.5-Sa, only the saTrQle from F-1 (which is very shallow and very near a surface <br />•nediarge source) has a Sodium Absorption Ration (S.A.Rr.) acceptable for <br />irrigation. According to the U.S. Salinity Laboratory of Standards, <br />and S.A.R. value of 18 or more is considered high and can develop <br />excess sodium in the soil resulting in damage to crops. Both samples <br />from t`~e "D" and "E" coal seams would be considered extremely high <br />S.A.R. values for irrigation use. <br />ALLi:~'IAL GLACIAL OUTY]?1SH AQUIFER <br />The major ground water source in this area is the surficial <br />glacial outwash and alluvial deposits which, as shown on the ~ ~, <br />Geology Map, 2.04.5- h oovers:a large percentage of the surface <br />above the mine permit area. This aquifer consists of basalt <br />boulders, cobbles, sand and clays derived ..through glacial erosion <br />of the volcanic materials capping Grand tdesa to the north. Accurnte <br />geologic data is not available because sampling of this material <br />is extremely 3ifficult due to the nature of the formation during <br />drilling. As can be seen on the Isopach Map-?llluvial Aquifer, <br />• 2.04.5-3, however, the thickness of this aquifer ranges up to ' <br />i <br />approximately 250 feet in the vicinity of the permit area. Although <br />no specific alluvial aquifer monitoring stations have been established, <br />it is concluded that the static water level in this formation is very ~' <br />near the surface. Evidence for this are the perennial streams <br />crossing the formation and the shallow reported static levels in <br />several wells in tine area. The Zsopac*~ Map-Alluvial Aquifer, 2.09.5=3, ar~cl Figures <br />2.04.5-1, 2.04.5-2, 2.04.5-2a, 2.04.5-3, 2.04.5-3a, 2.04.5-4, 2:04.5-4a, 2.04.5-5, <br />2.04.5-Sa, 2.04.5-Sb, 2.04.5-Sc, 2.04.5-6, axed 2.04.5-15, illustrate this evidence. ~ <br />Production capacity of wells completed in this alluvial aquifer can ' <br />only be estimated. ~o specific data is currently available from ~ <br />any wells fully penetrating the alluvium and having Seen tested <br />for an extensive period of time. The permeability and porosity <br />of this glacial outwash material, although high when compared ~ <br />with the coal seams and sandstone in this area, is not going to <br />be extremely high due to the glacial scour and clay material ' <br />• interspersed in the boulders and cobbles. It is estimated that <br />_ I <br />I <br />i <br />REVISED May 8, 1981 58 <br /> <br />