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• neutralized, while at the other site sufficient basic cations were present to <br />neutralize the acidity generated by the oxidization of pyrites in the coal. <br />Examination of their data suggests that EC, Ca, Mg and SAR's were <br />somewhat correlated by changes in pH. The highest EC, Ca and Mg and <br />lowest SAR values seemed to be associated with the lower pH areas. <br />Early reclamation research in North Dakota, (Wall and Freeman 1973) <br />demonstrated that one of six sites studied was considered to be acidic (pH <br />5.4j on a sRe mined 23 years earlier. Working in the San Juan Basin of <br />Northwestern New Mexico, where the average annual precipitation is less that <br />8 inches Gould et. al. (1975b) reported that regraded spoils mined one year <br />earlier had pH values as low as 5.1 and that the average pH values on some <br />areas was as low as 6.2. In a study looking at several copper and uranium <br />mill tailings sites in the various western states, Nielson and Peterson (1972) <br />reported that pH values as low as 1.9 were not uncommon in areas of very <br />low precipitation. Tailings at the Kennecott Magma tailings near Satt Lake <br />City were reported to drop from a pH value of 7 in June to a pH value of 3 <br />the following September. Working in southeastern Montana, Schafer et. al. <br />(1979) reported that coal fragments mixed in regraded spoil reclaimed seven <br />years earlier had oxidized sufficient pyritic sulfur to yield pH values as low <br />as 2.1. The corresponding SAR values on acidic "orphan spoils" were lower <br />than any other areas sampled. Barth and Martin (1982) reported that two of <br />the thirteen mines they evacuated in the Northern Great Plains possessed acid <br />• mine spoil. These sites had pH values of 3.6 and 4.3 respectively. The SAR <br />of these acidic spoils was less than 4.9. No ages of these materials were <br />reported. <br />Working at the Dave Johnston Mine in the southern end of the Powder <br />River Basin, Harvey and Dollhopf (1986) conducted what is undoubtedly the <br />most intensive characterization of western acid coal mine spoils that has been <br />completed to date. Data from their study are summarized in the following <br />comparison. <br />Relative % Relative % Relative 9'0 <br />iS~ge off SAR Pyritic-S Organic-S Sulfate-S <br />1 week 5.5 .48 22.6 39.1 38.3 <br />3 years 3.3 .25 15.6 35.2 49.8 <br />12 years 2.9 .24 13.2 29.8 57.1 <br />18 years 2.7 .12 7.4 26.1 66.0 <br />These data are particularly meaningful in that they clearly document the <br />processes normalcy associated with the acidification of these materials. The <br />• relative hydrogen ion concentration is dramatically increasing over time. This <br />decrease in pH is undoubtedly the result of oxidization of pyrites and organic <br />sulfur. Both of these constituents decreased over time, white the relative <br />percentage of sulfate sulfur, the by product of oxidization, progressively <br />increases as the pyrites and organic sufur oxidize. It is also noteworthy that <br />7 <br />