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American Tunnel). Measured flow from the Terry Tunnel now varies from 82 gpm in autumn <br /> to at least 1400 gpm during spring runoff. <br /> Drainage from both the American Tunnel and the Terry Tunnel is slightly acidic and contains <br /> elevated concentrations of metals. Although some of the metals content of the discharge from <br /> the American Tunnel is the result of sulfides exposed within the underground workings, much <br /> of the dissolved metals load is due to the natural metals content of ground water entering the <br /> tunnel. Much of the total metals content in the American Tunnel discharge originates from water <br /> entering the tunnel downstream of the SJCMV property line. Most, but not all, of the acid and <br /> metals content of drainage from the Terry Tunnel is a direct result of surface water reacting with <br /> sulfides exposed by mining. <br /> Drainage from both access tunnels is presently being treated with lime which both increases the <br /> pH and precipitates heavy metals. The resulting sludge is transported in tanker trucks to the <br /> tailings facility near the Mayflower Mill. <br /> sanjuan\sunny\110361\oct91.Rpt 3 <br />