Laserfiche WebLink
Hydro Investigation Results <br /> Santa Fe Formation-West Pit Battle Mountain Resources Inc. <br /> The Santa Fe Fm aquifer within the study area is a semi-confined system. The lithology of the <br /> Santa Fe Fm is variable,ranging from a claystone to a sandstone.The Santa Fe Fm aquifer typically <br /> underlies the alluvial aquifer. The Santa Fe Fm is typically separated from the underlying <br /> Precambrian gneiss/granite complex by a weathered clay unit. The average saturated thickness of <br /> the Santa Fe Fm aquifer is approximately 30 feet in the vicinity of the alluvial window of the West <br /> Pit. <br /> The investigation included the drilling, installation, and development of one well, conducting a <br /> pumping test of that well, and analysis of those test results. <br /> Results of the test analyses indicate that the consolidated sediments of the Santa Fe Fm aquifer <br /> have very low transmissivity, less than 0.12 fl/d, and hydraulic conductivity of approximately <br /> 0.003 ft/d. These values are consistent with estimates from previous investigations and are more <br /> than three orders of magnitude lower than estimates for the alluvial aquifer. <br /> The Santa Fe aquifer discharge into the West Pit along the eastern perimeter is calculated as <br /> approximately 0.022 gpm, much less than the 173 gpm previously estimated for the alluvial <br /> aquifer. The results of the WP-6 pumping test of the Santa Fe Fm aquifer are consistent with the <br /> conceptualization that the alluvial aquifer discharge into the West Pit accounts for the bulk of water <br /> that is currently being extracted from well BF-5. <br /> The hydrologic data collected and analyzed from this investigation will be incorporated into the <br /> West Pit groundwater models for further evaluation of the feasibility of remedial alternatives to <br /> reduce the volume of West Pit groundwater that must be treated prior to discharge. <br /> 6.0 REFERENCES <br /> Engineering Analytics,2022. Technical Memorandum,Hydrologic Investigation Results,Alluvial <br /> Window, Southeast Portion of the West Pit, Battle Mountain Mine. Prepared for Battle Mountain <br /> Resources, Inc. May 20, 2022. <br /> HydroSOLV, 2007. Aqtesolv Professional, Version 4.5-for Aquifer Test Analysis. Developed by <br /> G. Duffield. <br /> Neuman, S.P., 1972. Theory of flow in unconfined aquifers considering delayed gravity response <br /> of the water table, Water Resources Research,vol. 8,no. 4,pp. 1031-1045. <br /> Theis, C.V., 1935. The relation between the lowering of the piezometric surface and the rate and <br /> duration of discharge of a well using groundwater storage, Am. Geophys. Union Trans., vol.16, <br /> pp.519-524. <br /> LIST OF TABLES <br /> Table 1 Well Information,Santa Fe Formation Hydrologic Investigation,West Pit,San Luis <br /> Mine, Battle Mountain Resources, Inc. <br /> Table 2 Depth to Water, Total Well Depth, and Saturated Thickness, West Pit Hydrologic <br /> Investigation, San Luis Mine, Battle Mountain Resources, Inc. <br /> February 2023 8 Engineering Analytics,Inc. <br />