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.. , .... <br /> <br />ZORICH - ERKER ENGINEERING, INC. <br />Page 4 <br />There has been reported occurrnnce of small amounts of water <br />in the Burro Canyon formation in this area. However, due to the <br />presence of the upper Nbrrison formation shales and mnrlstones underlying <br />the Burro Canyon formation, the water occurrence in the Burro Canyon <br />is isolated from the proposed mule area and will not be affected b}' any <br />of the proposed mining operations. <br />' The Nbrrison formation in the study area is divided into two <br />memibers; the Brushy Basin member and the Salt Wash m~nber. The Salt <br />Wash member is the predoanix~ant source of the ore in this area. The <br />Salt Wash member underlies the Brushy Basin member, the average thickness <br />of the two members on a regional basis being 300 and 350 feet respectively. <br />The Brushy Basin member is oorrq~osed predominantly of shales <br />and mudstones with lenses of conglomerate and sandstone. This formation is <br />generally an aquitard with only minor amounts of water in isolated sand- <br />stone lenses. The Brushy Basin member is approximately 100 to 150 feet <br />thick in the area of the proposed pit mine. This member acts as a deter- <br />ent to direct recharge via surface infiltration to the sandstone lenses of <br />the Salt Wash m3nber. <br />The Salt Wash member is composed predominantly of gray to white, <br />very fine to miedium grained friable sandstone occurring in massive, but <br />lenticular beds interlayered with red shale and gray-green mudstone. The <br />shale and mudstone layers are sufficiently thick, as much as 50 feet, <br />and intertongue with the sandstone beds, producing isolated sandstone beds <br />therefore, forming a discontinuous aquifer. It has been noted from drill <br />