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NUCLA PR NO. 2 <br /> Nucla East mining area with hydrologic consulting firms and a number of <br /> experienced hydrologists. The general consensus was that rubber <br /> formation packers have little or no influence on the quality of the <br /> water samples. The following are a few reasons as to why the water <br /> quality is not influenced by the rubber formation packers : <br /> 1. Rubber is inert and will not leach or become soluble to any extent <br /> in a neutral or slightly alkaline pH environment. A very alkaline <br /> or very acidic solution would be necessary to cause any chemical <br /> reaction with the rubber. None of the Nucla monitoring wells are <br /> completed in water exhibiting such pH extremes. <br /> 2. Any leaching or dissolution of chemical constituents would involve <br /> organic constituents rather than inorganic ones. <br /> The only other possibility of contamination would be corrosion from the <br /> metal hose clamps (stainless steel ) used to hold the packer in place or <br /> possibly the cement baskets (carbon steel ) . The following table lists <br /> the typical alloys found in the types of steel that may be in contact <br /> with the monitor well water. <br /> Table 1 <br /> Chemical Constituent Carbon Steel Stainless Steel-Type 304 <br /> Carbon 0.30% max 0.08% <br /> Manganese 0.30-1.0% 2.06% max <br /> Phosphorus 0.04% max 0.040% max <br /> Sulphur 0.05% max 0.030% max <br /> Silicon 0. 12% max 0.75% max <br /> Chromium -- 18.0-20.0% <br /> Nickel -- 8.0-12% <br /> It is very likely that the metal clamps or cement baskets have little or <br /> no influence on the water quality of the monitor wells. By employing <br /> proper sampling techniques (removing stagnant bore water and achievin <br /> pH, temperature and conductivity stability prior to obtaining samples <br /> the possibility of trace element contamination should be negligible. <br /> Comment: <br /> 5. Peabody Coal Company presents two models in the Probable Hydrologic <br /> Impact section which were used to calculate pit inflows: The 1982 <br /> McWhorter model and the USGS finite difference model , MODFLOW. <br /> Were either of these models used to predict pit inflows at Nucla? <br /> How did actual pit inflow compare with the predicted flow? <br /> Response: <br /> Neither the 1982 McWhorter model or the USGS finite difference model , <br /> MODFLOW were used to predict pit inflows at the Nucla Mine. A <br /> 6 <br />