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cm/s. This conclusion is supported by laboratory testing that measured horizontal and <br />vertical permeabilities of less than 9.7 E -10 cm/s. For all practical purposes, this low <br />permeability value indicates that the Summerville Formation is an aquiclude - rock <br />incapable of transmitting groundwater. <br />Peel Environmental Services (1993) conducted hydraulic tests of the Kayenta Formation <br />using packer tests that showed the formation did not take water at a pressure of 745 psi. <br />Based on these tests, the report estimated that the permeability of the portions of Kayenta <br />Formation is 3.8E -08 cm/s - basically impermeable. The test interval was in a shale unit <br />of the Kayenta Formation and is not representative of the entire formation. However, the <br />lowest permeability unit controls flow for the entire formation. <br />For mining to impact the regional groundwater system, mobilized constituents would <br />have to migrate from the upper sandstone unit of the Salt Wash Member through the <br />lower sandstones and bentonitic shales of the lower portion of the Salt Wash, through the <br />impermeable Summerville Formation, the unsaturated Entrada and fine- grained Carmel <br />Formations, and the well- cemented siliceous sandstone and shales of the Kayenta <br />Formation before reaching groundwater in the Wingate Formation. This is an unlikely <br />scenario that indicates mining in the LP -21 area has no impact to groundwater resources. <br />8.3.4 Recharge <br />With the lack of well information, it is difficult to determine the upper -most aquifer in the <br />area. If the Wingate Formation is assumed to be the upper -most aquifer underlying the <br />LP -21 mine workings, based on well data from the Club Mesa area located approximately <br />four miles to the north, then this assumption is contingent on the additional assumption <br />that recharge for the Wingate Formation occurs along the flanks of the Paradox Valley. <br />While the literature indicates that there is insufficient precipitation to recharge the aquifer <br />in the exposed rock outcrops along the Paradox Valley walls, there are numerous faults <br />that run parallel to the valley that may collect the available precipitation and recharge the <br />aquifer. The LP -21 mine is located a little over a mile from a series of normal faults <br />associated with the breached anticlinal structure of the Paradox Valley. These series of <br />parallel faults result in rotational slump block where the surfaces of the blocks generally <br />tilt toward the fault directing the limited runoff from precipitation to the faults that <br />provide a pathway for recharge of the underlying formations. <br />As noted in Section 8.3.1, the Burro Canyon Formation forms the highlands above the <br />mine site and the exposed bedrock across the surface provides significantly more area for <br />recharge compared to the canyon walls for the lower stratigraphic units. Springs at the <br />Burro Canyon/Brushy Basin contact indicate limited quantities of groundwater are <br />isolated from the underlying mine by the impermeable shales of the Brushy Basin. <br />8.4 Groundwater Monitoring <br />Monitoring groundwater quality to specifications of the Resource Conservation and <br />Recovery Act (RCRA) or requirements of the DRMS is difficult. Simple concepts of up- <br />gradient and down - gradient monitoring wells at locations that could provide an early <br />O'Connor Design Group Inc. U - 14 <br />