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• Quartz, feldspar, and clay minerals occur as primary detrital minerals in sandstones and shales. <br />Clays, shales, and organic residues commonly have higher quantities of trace metals occurring as <br />adsorbed ions than do coarser grained strata. These ions maybe released into solution as a result <br />of oxidation and low pH. Other less commonly occurring minerals found in overburden strata <br />include calcite (CaCO 3), limonite (Fe2O3) and possibly siderite (FeCO,). Small deposits of <br />copiapite (FeO,) and halotrichite (Fe or Mg SO,) may occur as crusts on the faces of coal seams <br />and associated strata along outcrops near the New Horizon 2 mine area, (Caruccio et al., 1977). <br />Coal Seam Analysis. Table 2.04.6-1, Coal Seam Analysis Data, summarizes the quality of the <br />upper Dakota and lower Dakota coal seams for exploration drill holes placed within the New <br />Horizon 2 permit area. <br />New Horizon 2 Overburden Assessment <br />Chemical analyses of overburden samples obtained from the New Horizon 2 study area were performed <br />by Peabody Coal Company to identify any acid-forming, toxic-forming, alkalinity producing, or other <br />inhibitory materials present within the proposed mine boundary. Physical properties of the overburden <br />• were determined to define compaction, stability, permeability, erodibitity, and water holding <br />characteristics. Chemical and physical analyses also reveal the most desirable overburden strata to <br />be placed at the spoil surface and in the pit base. This baseline information is required prior to mining <br />to effectively prepare a mine plan that restores landscape productivity and which also minimizes <br />environmental degradation. Cross section E-E' has been extended to include lithology in the western <br />portion of the permit revision area (see map 2.04.6-3). Anew cross section H-H' has been prepared <br />as the dip section cross section in the area added under this permit revision (see Map 2.04.6-6). <br />Revised Map 2.04.6-1 shows the location of the geologic cross sections and the overburden sample <br />locations. One of the overburden sample locations, 881 E, is used in Geologic Cross Section E-E '. <br />Revised Cross Section E-E' and the new Cross Section H-H' show that the overburden to be mined <br />within the new permit revision area is of the same stratigraphic units of similar lithology to that sampled <br />at 881 E. The characterofthe overburden in the new permit area should be essentiallythe same as that <br />previously sampled. <br />• REVISED August 2006 2.(]4.6-11 <br />