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Hydro Investigation Results <br /> Santa Fe Formation-West Pit Battle Mountain Resources Inc. <br /> Aquifer properties that were estimated from the hydrologic test data include transmissivity (T), <br /> and hydraulic conductivity (K). Although storativity (S) can be estimated from pumping tests <br /> conducted in confined aquifers, for unconfined systems, it is generally equal to the drainable <br /> porosity of the aquifer matrix and is not reliably estimated from pumping tests. Also, storativity <br /> cannot be reliably estimated from drawdown data from the pumping well. Each of the aquifer <br /> properties listed are defined as follows: <br /> Transmissivity - Ability of an aquifer to transmit water - defined as the hydraulic <br /> conductivity multiplied by the vertical saturated thickness of the aquifer. Transmissivity is <br /> reported in this analysis as feet squared per day (ft2/d). <br /> Storativity- The amount of water released from an aquifer for a decline in hydraulic head <br /> (change in water level). For a confined aquifer, storativity is related to the compressibility <br /> of water and the compressibility of the aquifer matrix. For an unconfined aquifer, <br /> storativity is equal to the amount of water released due compressibility of water, the <br /> compressibility of the aquifer matrix and the specific yield (release of water stored in <br /> interstitial openings by gravity drainage). Water released as a result of aquifer <br /> compression and water expansion in a water-table aquifer yield are relatively minor <br /> compared to the amount derived from gravity drainage. The specific yield, also called <br /> drainable porosity or effective porosity, can never be more than the porosity of the aquifer <br /> matrix. <br /> Hydraulic Conductivity-A measure of the volume of water that can be transmitted through <br /> a unit cross-sectional area of an aquifer under a unit hydraulic gradient in a specific unit <br /> of time-essentially the permeability of the aquifer relative to water. Hydraulic conductivity <br /> is reported in this analysis as feet per day (ft/d) <br /> 3.2 Analysis of Pumping Test <br /> The Santa Fe Fm aquifer in the vicinity of the West Pit is best described as a semi-confined aquifer <br /> system. The top of casing for well WP-6 is approximately 5 ft above ground surface. The pre- <br /> pumping depth to water in WP-6 is approximately 27.4 ft btoc(or 22.4 ft bgs). This depth is similar <br /> to the depth to water in several of the surrounding alluvial monitor wells. Based on the total depth <br /> of the well at 90 ft bgs and the alluvium/Santa Fe Fm contact at 55 ft bgs,the saturated thickness <br /> of the Santa Fe aquifer in WP-6 is estimated at approximately 35 feet although the water level <br /> extends over 30 feet above the contact. It is unclear if there is a true confining layer between the <br /> alluvium and the Santa Fe Fm (possibly the weathered clay zone) that provides some degree of <br /> hydraulic separation between the two aquifers, or if the contact merely marks a transition from the <br /> highly transmissive alluvial aquifer into the much lower transmissivity of the Santa Fe Fm aquifer. <br /> Application of the Theis analytical method for the recovery data from the WP-6 pumping test <br /> yielded a transmissivity estimate of 0.119 feet3/day (ft3/d) (Figure 4). Based on a saturated <br /> thickness of 35 feet, the hydraulic conductivity estimated from that analysis is 0.0034 ft/d. <br /> February 2023 6 Engineering Analytics,Inc. <br />