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Two primary concerns identified by the Division as a part of the PR -1 review were <br />in regard to potentially acid forming materials associated with the Lennox coal seam <br />and excessive clay contents associated with shale strata overlying the Lennox. The <br />Division requested SCC to prepare a spoil sampling plan and mitigation plan for <br />areas where the Lennox would be spoiled, and for areas where the Lennox would <br />potentially be exposed by highwall reduction. A more detailed mitigation plan for <br />areas of excessive clay content was also requested. <br />SCC submitted an acceptable sampling plan to be employed in areas potentially <br />affected by Lennox spoil or outcrop within the original permit area. The same <br />sampling plan was to be applied to all regraded spoil areas and graded final <br />highwalls in the south extension mining block. The plan called for samples to be <br />taken on 500 foot centers within the designated area, and analyzed for clay content, <br />pH, and acid -base potential. Mitigation was to include additional sampling to define <br />the area of concern, deep ripping of areas of unsuitable clay content and amendment <br />or burial of acid forming material with a minimum of four feet of suitable material <br />as cover. The regraded areas were sampled during reclamation as required, and all of <br />the samples indicated no mitigation would be required. <br />Nitrate - nitrogen levels were excessive in 14 % of the overburden core samples taken <br />at the Seneca II -W Mine. The locations of the holes which exhibited elevated levels <br />were distant from one another. Furthermore, the stratigraphic locations of the <br />elevated nitrate - nitrogen samples are not correlative. Due to the vertical and <br />horizontal distances between locations containing elevated nitrate - nitrogen levels, <br />percolating ground water will not be adversely affected. The dilutional effects of a <br />predicted spoils aquifer should buffer the concentration of nitrate as nitrogen by the <br />time the aquifer discharges to the surface system. <br />Wolf Creek/Sage Creek Overburden/Underburden Assessment <br />Only two parameters (iron and lead) exhibited unsuitable levels within sampled <br />increments from the one bore hole that penetrated the sequence in the south <br />extension area. Within each of four delineated intervals (Sage Creek overburden, <br />Upper Wolf Creek overburden, Lower Wolf Creek overburden, and Wolf Creek <br />underburden), composite samples were taken from each 10 foot depth increment. <br />The average value for lead within the Lower Wolf Creek overburden interval was in <br />the unsuitable range, due to a very high value within one of five sampled <br />increments. One or more sample increments within the Sage Creek and Wolf Creek <br />overburden intervals exhibited unsuitable iron levels, but the average iron level <br />within each interval was suitable. One of six sampled increments in the Upper Wolf <br />Creek overburden was in the unsuitable range for lead, but the average value for the <br />interval was marginally suitable. Concern relative to elevated levels of the two <br />metals are minimized due to the neutral to slightly basic pH range indicated within <br />each sampled increment, and the resulting low solubility of the metals. <br />Seneca II -W Findings Document 24 C- 1982 -057 <br />Permit Revision No. 6 January 6, 2012 <br />