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basis of formation thicknesses, However, he points out that such estimates . may not always be accurate because of displacements by faults. Table 2.04.5-2 shows data on wells within an approximate one mile radius of the permit area (See also Figure 2.04.5-5 for well locations). The deepest well is 200 feet and almost all of the rest are under 100 feet. Recorded water levels range between 22 feet and 150 feet, There is no indication of the aquifers which these wells penetrate, Records on additional wells in the area are given under Section 2.04.'](1). Inflow of appreciable ground water is reported to have hindered underground coal mining at deeper levels, particularly in the mines nearer to the valleys of the Cucharas River, Bear Creek and Santa Clara Creek, Table 2,04.5-3 from McLaughlin's report shows the amount of water stored in these abandoned mines. Mines below and nearer to valleys reportedly had higher yields because of the direct recharge into the coal bearing formations from saturated valley fills, Most of the valleys in the general area of the permit have steep gradients and shallow alluvial deposits. The thickest alluvial deposit in Huerfano County is about 50 feet and is found along the Huerfano Valley. For • Santa Clara Creek, which is closer to the permit area the maximum thickness is estimated to be 30 feet (McLaughlin, 1966). Within the permit area, the unconsolidated sediments in the Pryor Canyon are 20 feet thick, In adjacent Black Hawk Canyon the alluvial deposit is estimated to be between 20 to 25 feet thick. The quality of ground water in sedimentary rocks generally decreases with depth. In Huerfano County the groundwater from the sedimentary formations at depth as well as from alluvial aquifers is highly mineralized (McLaughlin, 1966). Mine water is low to very high in sodium absorption ratio (SAR) and medium to very high in salinity (Figure 2.04.5-6). Alluvial water is low to medium in SAR and medium to very high in salinity (Figure 2.04.5-7). Water from the Trinidad Sandstone, however, is classified as low in SAR and medium to high in salinity (Figure 2.04.5-8). • JFSA- 8 ~ O a ,. 1 E SAtQ & ASSOGATFS. INC.