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In the deeper parts of the American 'funnel (farther than approximately 2500 feet from the <br /> portal) the majority of water transmitted to the tunnel originates from a few fracture zones <br /> (Figure 10). Major permeable zones include the Washington vein (190 gpm), the Brenneman <br /> vein (200 gpm) the Sunnyside vein (180 gpm), a fracture zone at the 0700 runaround <br /> (approximately 340 gpm), and a fracture zone located 3020 to 3220 feet from the outside end <br /> of the track (approximately 400 gpm). <br /> Within approximately 2500 feet of the portal minor joints transmit a significant amount of water. <br /> The increased permeability of the minor joints is due to a decrease in overburden pressure near <br /> the portal. This zone of generalized permeability accounts for approximately 32% of the flow <br /> leaving the portal. <br /> On October 2-3, 1991 flow measurements showed 930 gpm of flow from the American Tunnel <br /> originated on SJCMV property. More than half(57%) of the discharge of the American Tunnel, <br /> amounting to 1230 gpm, entered the tunnel downstream of the property line. <br /> 4.2.2 Chemistry of Ming Waters <br /> Most of the water entering the American Tunnel is ground water draining from fractures. This <br /> ground water locally contains relatively high concentrations of lead, zinc, cadmium, iron, and <br /> manganese. The chemistry of wa er entering the American Tunnel is discussed in further detail <br /> in section 3.1.5. Water discharging from the American Tunnel has a mean field pH value of <br /> 6.4, and a mean laboratory pH value of 5.4. Mean laboratory conductivity is 1,870 micro-mhos <br /> sanjuan\sunny\11036 1\oct9 1.Rpt 41 <br /> effl s i m o n o0 0 o00000 <br />