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data, the study concludes that contamination from the use of ash in roadway subsoil can be avoided by careful planning, on a site-specific basis. It would appear that no direct conclusion can be drawn from this study, as to how it pertains to the Trapper Mine, since the results would depend upon site-specific conditions. Further study would be required at the actual site, as it pertains to ground water hydrologX and near surface soil permeability, before the Division can approve such a plan. This study presented data from five sites, located in Georgia, Arkansas, Pennsylvania, Kansas and Arizona. It would seem logical that the data from Arizona and Kansas would be more relevant to Colorado than would the other sites. It would appear that the data at these two sites have some problems. On page 6-15 of the study it is stated that there is no downgradient well at the Arizona site. Also, the statistical conclusions from the Arizona site were described, on page 6-17 of the report, as "tentative because of the scarcity of the data." At the Kansas site, the study was somewhat hampered by local variations in native chemical constituents, as reported on pages 5-15 and 5-16. However, the study found, as stated on page 5-16, that limited leaching of ash constituents is occurring down to a depth of about three feet. This was after six years of fly ash use. The Division believes that it should not base its decision, for this kind of a project, on data from just two sites, when one of the two sites, in Arizona, has inconclusive evidence. The other site, in Kansas, did show some leaching of fly ash constituents, but levels were below regulatory standards (see No. 3 below), except for sulfate, which the study concludes is due to native sulfates, not fly ash (see page 5-19). The Division could not find any reference in this report as to how EPA classifies fly ash. Also, there does not seem to be a clear explanation of which regulatory standards are being used in the analyses. Each analyses section for each of the five sites in this report contains a table which lists the regulatory levels for eight chemical ions. There are two regulatory levels listed. One is TCLP (toxicity characteristic leaching procedure) and the other is MCL (maximum contaminant level). For example, Table 6-5, on page 6-11, lists TCLP and MCL levels for the Arizona site, both in mg/L. On page 6-10 there is a discussion of the results of Table 6-5. The eight metals listed in the table are RCRA metals so, it is assumed, all of the regulatory standards used in this study are related to RCRA, and, therefore, are from the EPA.