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• (mean 0.071 mmhos/cm, t=2.01, p < 0.05). The parameters related to <br />sodicity were sampled on the sites but not discussed in the narrative. <br />However, data are presented documenting that the sodium content of the <br />new refuse (mean =1.68 meq/100g) was greater than that associated with the <br />old refuse (mean=0.28 meq/100g). The t statistic comparing the old and <br />new refuse sodium levels equals 2.097, which means that these means are <br />signficantly different at the 0.10 level. Sodium adsorption ratio values were <br />also collected from 16 sites but these data were not analyzed or discussed <br />in this report. A t-test comparison of these data reveals that the mean SAR <br />of the new refuse is signficanty higher (mean =1.31) than the mean of the old <br />refuse (mean=0.32, t=2.336, p < 0.05). They concluded that as a whole the <br />refuse materials 'appeared to be a suitable medium as a plant growth <br />medium". <br />Research on an abandoned coal refuse pile 38 years old in Montana (Gift <br />and Dollhopf 1987) revealed that this refuse material was highly acidic (pH <br />2.8), with high levels of iron, sulfate, and extractable aluminum. Salinity and <br />sodicity related parameters were quite low (EC=3.59, and ESP= < 0.01). <br />The results of a five year study involving the refuse materials at a large <br />underground mine site in Utah were recenty summarized by Crofts and <br />Grimes (1988). Refuse ranging in age from fresh to eighteen years old was <br />evaluated. The refuse materials were found to have lower pH, calcium, <br />calcium carbonate, sift and clay levels than undisturbed soils but higher EC, <br />• saturation percentage, selenium, boron, sulfur, and sand levels. Upon <br />applying the topsoil suitability criteria to these refuse materials it was found <br />that the refuse was inferior to the native soils with respect to EC, selenium <br />and acid base potentials while the native soils were inferior with respect to <br />alkaline pH, texture, and high clay content. Since the limiting factors of the <br />soils were Mixed' while the limiting factors of the refuse were readily <br />correctable, it was determined that as measured by the existing topsoil <br />suitability criteria, the refuse materials were of higher quality than the native <br />soils. The lowest pH value observed was 6.5. There was a very poor <br />correlation between the calculated acid base potential values and field acidity <br />as measured by pH, after 18 years of weathering. <br />IMPACTS OF COAL CLEANING ON WESTERN COAL WASTE <br />MATERIALS <br />Avery common conception regarding the mixing of coal with waste rock <br />materials or soil is that the resuking mixture will be high in trace elements and <br />of lower overall quality. This is documented by the OSM and CMLRD <br />regulations in defining 'coal processing wastes' wherein it is automatically <br />assumed that all such materials are considered to be toxic and acid forming. <br />As simple as this concept is, it is poorly supported by available scientific <br />I'derature which describes the properties of western coal refuse materials. <br />Fortunately, abundant research has been conducted on the fate of various <br />• parameters during the coal benefication process. Much of this research has <br />been conducted by the EPA in hopes of reducing the airborne emissions <br />resuRing from the combustion of coal in coal fired power plants. The resuk <br />of these studies have direct application in understanding the processes <br />involved with the processing of western coals. Spaite et. at. (1979) <br />5 <br />