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sampled on a 300 foot grid for sodium. Exposed sodic material, as identified <br />by the sampling program, will either be buried in the final pit or covered by <br />two to three feet of suitable spoil material. <br />Peabody Coal Company currently samples the Wolf Creek spoil on a 300 foot grid <br />pattern for laboratory geochemical analysis. The analysis indicates that the <br />success of mitigating excessive concentrations of certain geochemical <br />parameters varies over the Wolf Creek area. Therefore, Peabody Coal Company <br />has committed to an ongoing monitoring and evaluation program to determine <br />re vegetation success on the spoil material. <br />Peabody Coal Company has determined that Acid Base Potential (ABP), rather <br />than pH, is a more useful tool for determining the possibility of future acid <br />production in the spoil. The Division concurs with this determination and <br />concurs with the assessment that an ABP value of -5 should be used to separate <br />suitable from unsuitable spoil materials. <br />Based upon this criteria, Peabody Coal Company has identified three areas <br />which exhibit critical ABP values in the Wolf Creek mining area. These areas <br />are the sites of samples WC-60, WC-64 and WC-65 (Exhibit 9-4). In order to <br />mitigate the potential impacts to reclamation success, Peabody Coal Company <br />has committed to covering these acid spoil areas with two to three feet of <br />suitable spoil material. This material will be transported from the vicinity <br />of sample sites WC-56, WC-57 and WC-62 (Exhibit 9-4), where analysis indicates <br />that this material is suitable for this purpose. Otherwise, sufficient <br />quantities of agricultural grade limestone will be added to the spoil to raise <br />the pH of the upper 12 to 24 inches of spoil to between pN 5.5 and pH 7.0. <br />In order to identify potential acidity problems in previously reclaimed <br />portions of the Wolf Creek mining area, Peabody Coal Company is monitoring <br />reestablished vegetation at sample sites WC-1 through WC-5, WC-29, WC-31, <br />WC-33, WC-35, WC-36, WC-42 and WC-45 (Exhibit 9-4). <br />Potential revegetation problems associated with high manganese levels at sites <br />WC-25, WC-26, WC-27, WC-29 and WC-3 (Exhibit 9-4) are currently being <br />investigated, as is the upward migration of spoil acidity into the reapplied <br />topsoil. The investigation will continue into the 1987 field season, however, <br />Peabody Coal Company will submit the preliminary results to the Division by <br />February, 1987. <br />The original permit document indicated excessively high nitrate concentrations <br />from portions of the overburden at the Seneca II t4ine site. Peabody Coal <br />Company has determined that a percentage of the excess was due to improper <br />sample handling. To determine if a nitrate toxicity problem exists, Peabody <br />Coal Company evaluated spoils aquifer discharges from the mine site to check <br />for excessive nitrate concentrations in the water. Water discharging from the <br />mine spoils does not exhibit elevated nitrate/nitrogen levels; however, to <br />further evaluate the potential for nitrate toxicity, Peabody Coal Company has <br />committed to collecting and analyzing spoil samples for N03 and NH4-N from <br />representative vegetation transects in the Wadge mining area. <br />The operation is in compliance with the requirements of this section. <br />-10- <br />