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Whirlwind Mine Groundwater Characterization Report <br /> 6.2 Groundwater Hydrology <br /> Multiple investigations have consistently identified several hydrostratigraphic units in the project <br /> area as described in Section 4.2. These include the Burro Canyon aquifer and up to three zones <br /> within the Brushy Basin Member. There is no consistent evidence that the Salt Wash Member is <br /> water bearing; however, it is suspected that the Salt Wash Top Rim sandstone may be <br /> saturated in places but yields groundwater slowly due to its low permeability. <br /> 6.2.1 Burro Canyon <br /> The Burro Canyon aquifer has been documented in Umetco Borehole BM00-1, Cotter <br /> exploration holes, EFR exploration holes, and the Dolores Point water supply well. Other water <br /> sources include the two Cherokee water supply wells and Willow Spring. Information from <br /> borehole BM00-1 shows that groundwater was encountered at about 90 ft near the interpreted <br /> base of the Burro Canyon but was a minor amount and could not be tested. The interpreted top <br /> of the Brushy Basin was at 105 ft. An open-hole test was conducted from 93 to 140 ft. Also, the <br /> Dolores Point well log shows some water was encountered at a 70-foot depth and a hard <br /> limestone bed was present at 75-80 ft; the main water zone at 105 to 115 ft was in sandstone of <br /> the Burro Canyon. The well was drilled another 35 ft into shale of the Brushy Basin. The Dolores <br /> Point well log confirms that the main aquifer was in the interpreted Burro Canyon. Of the seven <br /> exploration holes drilled by Cotter in 1996, groundwater was encountered in only one hole, with <br /> a yield of less than 2 gpm. <br /> Exploration drilling by Cotter in 1996 (see Table 1) showed a drill hole yield of less than 2 gpm <br /> from the Burro Canyon in hole JB-96-1 and only damp conditions in the Burro Canyon in hole <br /> JB-96-2. Five other drill holes did not report groundwater encountered in the Burro Canyon. <br /> Two of 14 exploration holes drilled by EFR in 2007 on Dolores Point required injection at <br /> 120 and 150 ft, indicating the presence of Burro Canyon groundwater. These holes were <br /> located at the southern and northern ends of the 14 holes drilled by EFR. <br /> Spring discharge of Burro Canyon groundwater occurs at DP Springs and Willow Springs. <br /> These springs occur at the base of the formation and within Quaternary-age landslide and <br /> slump deposits. Spring discharge is common in this type of setting. Slope failures often occur <br /> where the slope material has become saturated and weakened. DP Spring may be related to <br /> Western Water& Land, Inc. 35 <br />