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Characteristics of the overburden aquifer determined for specific monitoring wells in the permit and adjacent areas <br />• are summarized in Exhibit 9, Aquifer Test data. The highest hydraulic conductivity values for the overburden <br />aquifer (0.4 to 0.86 ft/day) were calculated from pumping test data (Well FBR-1 and FBR-4). <br />Pumped well data from Exhibit 9 indicates that the Wadge Overburden aquifer has an average permeability ranging <br />from 0.11 to 0.32 R/day, which is consistent with the low yields observed in the monitoring wells. <br />Alluvial Aquifers <br />The locations of significant alluvial deposits in the Foidel Creek drainage in the vicinity of the permit area are <br />shown on Map 15, Alluvial Valley Floors and Surface Water Rights. <br />A cross section through the alluvial sediments near the confluence of Foidel and Middle Creeks is present in Figure <br />6T. <br />Grouud Water Quality <br />The discussion of ground water quality will be limited to the aquifer units, which influence, or may be potentially <br />affected by, the proposed mining operation. As shown in Exhibit 14, Hydrologic Monitoring, a number of ground <br />water monitoring wells completed in the significant aquifers of the Twentymile Park Basin exist in the permit and <br />adjacent areas. Ground water levels and quality in some of these wells have been monitored since 1979. <br />Bedrock Aquifers <br />Water quality data from well 001-83-106 indicates that the Trout Creek Sandstone aquifer baseline water quality if <br />of sodium bicarbonate type with moderate sulfate concentrations and very low concentrations of calcium and <br />magnesium. Total dissolved solids concentrations are in the range of 822 to 876 mgll and pH ranges between 8.7 to <br />9.0 units. Water quality in well 001-83-107 is similaz to water quality in we11001-83-106. <br />Known Uses of Ground <br />A review of the Colorado State Engineers' records indicate the existence of several adjudicated wells within the <br />general vicinity of the permit area. The wells are located within approximately a 2 mile radius of the permit area <br />(Exhibit 6H, Summary of Ground Water Rights). The location and completion information for these wells was <br />examined to ascertain whether there is any potential for adverse impacts as a result of the proposed mining <br />operation. <br />The quality data from the Wadge Overburden wells indicate that ground water in this aquifer is characteristically of <br />a sodium bicarbonate type with relatively low concentrations of calcium, magnesium, and sulfate ions. Total <br />dissolved solids concentrations are typically in the rutge of 400 to 2042 mg/I and pH concentrations are 8.3 units <br />(well FBR-1lA). The four wells presently monitored under this permit as Wadge Overburden Wells (009-79-4, <br />006-82-74C, 91M006, and FBR-11-A) have an average total dissolved solids concentration of 1952 mg/I and an <br />average pH of 8.02. The average changes to 1588 mg/I total dissolved solids and a pH of 8.18 unit if monitoring <br />well 006-82-74C (located near the portal area) is excluded from the group. Monitoring well 026-79-4, which is <br />farther upgradient and outside the permit area, has a range from 384 to 1510 mg/I total dissolved solids <br />concentration and has an average 673 mg/I total dissolved solids from 1979 to 1993. The average pH value for this <br />well is 7.98 units for the period 1979 to 1993. <br />~q~ <br />^ ~ ~.~ ~ <br />~''" <br />Permit Renewal No. 3 2.04-42 12/10/98 <br />