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calibrations are performed by using the pH 7 and pH 10 buffer solutions, since the pH of <br /> most waters sampled at the Nucla and Nucla East Mines range between 7 and 9 pH units. <br /> However, the lower buffer solution (pH 4) is used for two point calibrations prior to <br /> measuring water historically known to exhibit pH values less than 7 pH units. One-point <br /> calibrations involve using the pH 7 buffer solution. <br /> Table 3 presents the current parameter list for surface water sample analysis at the Nucla <br /> Mine. As requested by CMLRD in a letter from Mr. John Doerfer submitted to Peabody on May <br /> 4, 1987, Peabody has revised the parameter list to include total recoverable analysis of <br /> metals instead of total analyses. Total recoverable analysis for the parameters listed in <br /> Table 3 have been performed since March 25 of 1987. This revised surface water parameter <br /> list also applies to analyses performed on samples obtained at all Nucla East monitoring <br /> sites. <br /> Silver and chromium were analyzed for twice during the 1987 water year in samples obtained <br /> from both surface and ground water samples taken from monitors at both the Nucla and Nucla <br /> East mining areas. The results of these analyses can be found in Appendices D, E, and J. <br /> Upon further perusal of the data, Peabody will submit a formal request to the MLRD for a <br /> variance from sampling for silver and chromium in both surface and ground water. <br /> Baseline Monitoring Program - Nucla East. Surface water monitoring activities conducted <br /> since July of 1986 at monitoring sites established in and around Peabody's proposed Nucla <br /> East mining area have been consistent with the approved baseline monitoring program. This <br /> program was proposed and outlined in a letter submitted to Mr. Steve Renner from Peabody <br /> personnel on April 21, 1986. Approval of the baseline monitoring program for the Nucla <br /> _ East mining areas was issued, with minor amendments, in a letter received by Peabody from <br /> Mr. Peter O'Connor of CMLRD on May 6, 1986. The locations of each surface water <br /> monitoring site in the Nucla East area is presented on Exhibit 1. Table 4 lists each <br /> Nucla East surface water monitoring site, location and type of measurement performed. <br /> Data Summary. Surface water data (including NPDES monitoring data) collected at the Nucla <br /> Mine and Nucla East mining area during the 1987 water year are presented in Appendices B <br /> through E (see List of Appendices, Table of Contents). Nucla East data collected since <br /> July of 1986 are included in these attachments. Two sets of water quality data are <br /> provided, as the first set includes reports of analyses performed for total metals, and <br /> the second set includes reports of analyses for total recoverable metals, which began in <br /> March of 1987. <br /> 8 <br />