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2.0 GROUNDWATER MONITORING WELL M -14 <br />i <br />Well M -14 is part of the groundwater quality monitoring system for the LTF and collection pond <br />which consists of a network of monitoring wells and lysimeters to ensure that the system remains <br />protective of downgradient water resources. Well M -14 is approximately 80 feet west from the <br />toe of the main embankment of the tailing pond and approximately 60 feet south of the LTF <br />collection ditch as shown in Figure 1. The LTF groundwater quality monitoring system also <br />includes six (6) additional groundwater monitoring wells (M -12, M -13R, M -6, M -7, M -8 and M- , <br />9) and six (6) lysimeters (LIS, LID, L2S, L2D, L3S and L3D) which are also shown in Figure 1. <br />These wells and lysimeters are constructed in the various horizons of the unsaturated and saturated <br />Santa Fe Formation in order to identify potential fluid loss from the LTF and collection pond. <br />2.1 Well Construction i <br />Groundwater monitoring well M -14 was constructed in October 1993 and is a 4 -inch diameter well <br />completed in the saturated zone of the Santa Fe Formation. The well was constructed from 150 <br />feet of Schedule -40 flush - threaded polyvinyl chloride (PVC) risers and 30 feet of slotted well <br />screen (0.010 -inch) with a bottom cap, for a total well depth of 180 feet. Silica Sand 10 -20 filter <br />pack was installed to above the well screen and a bentonite pellet seal was installed above the filter <br />pack. A continuous bentonite grout seal is installed from the pellet seal to a concrete surface seal <br />three (3) feet below the ground surface. The surface completion includes a lockable 6 -inch steel <br />protective casing. <br />2.2 Geologic and Hydrogeologic Conditions <br />The geologic log of well M -14 indicates sequences of clays and sandy clays with coarser grained <br />sands and gravel lenses, which is typical of the interbedded nature of the Santa Fe Formation, with <br />thin layering of coarser material throughout sandy clays. Given the layered nature of the Santa Fe <br />Formation and the relatively low permeability of the sediments, the preferential flow path near M- <br />14 and the LTF is believed to be mainly lateral rather than vertical. A large volume of water would <br />need to be present to overcome specific retention of the unsaturated materials and reach the <br />groundwater table. <br />TR -32 M -14 TDS Response Plan Report AES, Inc. <br />Battle Mountain Resources — San Luis, CO 2 January 2015 (Update) <br />