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The applicant has submitted detailed analysis of the geochemical characteristics of the <br />overburden and interburden found in the Seneca II-W Mine permit area. Initial drilling <br />and geochemical sampling was conducted within the baseline study area prior to <br />initiation of operations. Additional drilling and sampling was conducted within the <br />south extension area in 1991. Until approval of PR-3, in 2003, coal extraction was <br />limited to the Wadge seam, and the initial baseline studies were focused on Wadge <br />overburden assessment. Strata from the surface to immediately below the Wadge coal <br />seam were sampled. Core holes were distributed across the Wadge recovery areas in <br />both the original permit area and south extension area (Exhibits 6-6 and 6-6A). <br />PR-3 allowed for surface mining of the Sage Creek and Wolf Creek Seams, as well as <br />the Wadge, within the South Extension area. Characterization and assessment of Sage <br />Creek and Wolf Creek overburden, and Wolf Creek underburden was based on chip <br />samples collected from Monitoring Well WWCU-24, which was drilled into the Wolf <br />Creek underburden near the western boundary of the south extension area in 2001 <br />(Exhibit 7-1A). In addition to the site specific geochemical data from WWCU-24, <br />Sage Creek/Wolf Creek overburden characterization and assessment included <br />consideration of data from the adjacent Yoast Mine permit area, for the same strata. <br />Parameters sampled are listed in the permit application Volume 2, Tab 6. The permit <br />application states that these parameters were used to, "document the physical and <br />chemical properties of the overburden and underburden, to compare these properties to <br />ground water quality, and to determine potential reclamation success." <br />The data obtained from the geochemical analyses were compared to criteria derived <br />from State and Federal agencies (USDA, BLM, Wyoming DEQ, and others). The <br />criteria used for comparison and relative degrees of suitability are listed in Volume 2, <br />Tab 6, Table 6-3. Analytical data associated with Wadge overburden and immediate <br />underburden is presented in Tables 6-4 through 6-7, and Appendices 6-3 and 6-4 of <br />Tab 6. Analytical data associated with Wolf Creek and Sage Creek overburden and <br />underburden is presented in Tables 6-7A through 6-71), and Appendix 6-3 of Tab 6. <br />Summary tables and text delineating unsuitable zones and addressing mitigative <br />measures for unsuitable zones within Wadge, Wolf Creek and Sage Creek overburden <br />and underburden are included in Appendix 6-5. <br />Wadge Overburden/Underburden Assessment <br />In 4% or less of the samples analyzed, pH, acid/base potential, boron, manganese, <br />cadmium and zinc exceeded suspect levels. In general, the Division concurs with the <br />applicant's determination that normal mixing of overburden will mitigate the toxic <br />effects of these materials. D.J. Dollhopf in "Selective Placement of Strip Mine <br />Overburden in Montana" (Chapter 5, Summary Report, 1981) suggests that if the <br />Seneca II-W Findings Document 25 C1982057 <br />Permit Renewal No. 5 December 9, 2010