Laserfiche WebLink
Unsuitable material was identified in the overburden at 9 of the 15 sample locations • <br />within the proposed disturbance area. The unsuitable parameters, pN, saturation <br />percentage, particle size, boron, nitrate nitrogen, acid-base potential, manganese, iron, <br />zinc, copper, and coal comprise 1.1 to 52.4 percent of the overburden section (Tab b, <br />Appendix 6-5) at the sample sites. These parameters are discussed in greater detail in <br />the following section. <br />Acid- and Toxic-Forming Materials. Acid- and toxic-forming materials were identified in <br />the Seneca I[-W study area as discussed in Tab 6 end listed in Tah 6, Appendices 6-3 and <br />b-5. Appropriate mitigation measures such as avoidance, ameliorating reclamation <br />techniques, or blending, dilution, and/or burial by normal overburden handling, will be <br />used to replace a suitable four-foot root growth medium, including topsoil, end to prevent <br />leachates and runoff from entering the ground Mater system or discharging into the surface <br />water system. No roads will be surfaced with acid-forming materials. <br />Mitigation of aLL unsuitable zones within the underburden material (17 percent of all 77 <br />unsuitable zones which were identified) will be by avoidance, i.e., these zones will not <br />be disturbed by mining activities. Mitigation of all unsuitable pM, saturation • <br />percentage, boron, etid-base potential, iron, zinc, copper, and coal zones will be by <br />overburden blending, dilution, and/or burial by normal overburden handling techniques. <br />(1 <br />All of these zones comprise 15 percent or less of the overburden section (Tab 6, Appendix <br />b-5). According to Dollhopf et al. (1978), overburden zones of unsuitable quality <br />material will, with mathematical reasoning, be acceptable material for reclamation by the <br />spoil mixing phenomena. The degree of mixing can be ascertained by compering the amount <br />of uns uita6le overburden to the amount present in the resultant spoils. These results <br />generally showed that when critical parameter percentages comprise 0 to 15 percent of the <br />overburden core, the parameter is blended and completely diluted during the course of <br />mining. <br />Ameliorating reclamation techniques and blending, dilution, and/or burial 6y typical <br />overburden handling will be used to mitigate excessive levels of clay. Unsuitable clay <br />percentages comprise Less than 15 percent of the overburden section at Sites 42-L, 1127-E, <br />and 1129-E. Typical overburden handling by cast blasting, dragline spoiling, and dozer <br />grading at these three sites will effectively blend, dilute, and/or bury the unsuitable <br />clay strata. Typical overburden handling operations are described in Tab 12, Coal • <br />Resource Recovery Plan and Tab 20, gackf illiny and Grading. <br />2 <br />