|
Wadge mining area for the Seneca II Mine. The only significant difference between mine areas is more
<br />shaley Lennox overburden exists within the disturbance area at Seneca II-W. Approximately 78 percent •
<br />of the overburden material is classified as suitable for root growth and aquifer medium material (Tab 6,
<br />Appendix 6-5 and Tabte 6-31. All overburden and underburden strata had suitable values for salinity,
<br />sodium adsorption ratio, molybdenum, selenium, arsenic, cadmium, mercury, and lead.
<br />Unsuitable material was identified in the overburden at 9 of the 15 sample locations within the
<br />proposed disturbance area. The unsuitable parameters, pH, saturation percentage, particle size, boron,
<br />nitrate nitrogen, acid-base potential, manganese, iron, zinc, copper, and coal comprise 1.1 to 52.4
<br />percent of the overburden section (Tab 6, Appendix 6-51 at the sample sites. These parameters are
<br />discussed in greater detail in the following section.
<br />Acid- and Toxic-Forming Materials. Acid- and toxic-forming materials were identified in the Seneca II-W
<br />study area as discussed in Tab 6 and listed in Tab 6, Appendices 63 and 6-5. Appropriate mitigation
<br />measures such as avoidance, ameliorating reclamation techniques, or blending, dilution, and/or burial by
<br />normal overburden handling, will be used to replace a suitable four-foot root growth medium, including
<br />topsoil, and to prevent leachates and runoff from entering the ground water system or discharging into
<br />the surface water system. No roads will be surfaced with acid-forming materials.
<br />Mitigation of all unsuitable zones within the underburden material 117 percent of all 77 unsuitable zones •
<br />which were identified) will be by avoidance, i.e., these zones will not be disturbed by mining activities.
<br />Mitigation of all unsuitable pH, saturation percentage, boron, acid-base potential, iron, zinc, copper, and
<br />coal zones will be by overburden blending, dilution, and/or burial by normal overburden handling
<br />techniques. All of these zones comprise 15 percent or less of the overburden section ITab 6, Appendix
<br />6-51. According to Dollhopf et al. (19781, overburden zones of unsuitable quality material will, with
<br />mathematical reasoning, be acceptable material for reclamation by the spoil mixing phenomena. The
<br />degree of mixing can be ascertained by comparing the amount of unsuitable overburden to the amount
<br />present in the resultant spoils. These results generally showed that when critical parameter
<br />percentages comprise 0 to 15 percent of the overburden core, the parameter is blended and completely
<br />diluted during the course of mining.
<br />Ameliorating reclamation techniques and blending, dilution, and/or burial by typical overburden handling
<br />will be used to mitigate excessive levels of clay. Unsuitable clay percentages comprise less than 15
<br />percent of the overburden section at Sites 42-C, 1127-E, and 1129-E. Typical overburden handling by
<br />cast blasting, dragline spoiling, and dozer grading at these three sites will effectively blend, dilute,
<br />•
<br />TR-50 2 Revised 11 /04
<br />
|