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t~ <br />the tested materials are compositionally appropriate for the tests they are being used <br />in to characterize behavior of this type of Cresson overburden material. <br />Meteoric Rinse Tests on Historic Waste Duma 5amoles <br />The test data on the seven samples of waste dump materials from the vicinity of the <br />Cresson project are interesting mostly in terms of their relationship to how materials <br />generally similar to the Cresson overburden materials have responded to weathering in the <br />natural environment. <br />Comparison of the meteoric rinse water pH and trace metals levels in these tests with <br />eazlier tests on Cresson materials and with the humidity cell test data in this report seems <br />to confirm the postulate that these materials are behaving in a manner similaz to that of <br />Cresson materials under somewhat similar conditions. <br />The meteoric rinse water testing of these materials adds weight to the arguments for <br />what we can expect the Cresson overburden materials of similar composition to do <br />in a similar environmental exposure. Without more information on the specific <br />composition of the waste rock materials and on how historical weathering has <br />impacted composition and minerals reactivity, any more exact comparison and <br />projection of behavior is probably not warranted. The authors of the report appear <br />to have included this data as a source of general supporting information and I do <br />not see any major emphasis placed on the results for reasons other than increased <br />perspective on materials weathering in the Cresson project vicinity. <br />Humidity Cell Test Dafa <br />The humidity cell test data for the 22 samples which have been in testing for periods <br />ranging from 6 to 60 weeks represents the data which is probably closest to a simulation <br />of likely weathering reactions of these materials in whatever area they aze deposited at the <br />Cresson project site. <br />The two major issues addressed by the humidity cell test data are the generation of acid <br />and the mobilization of trace metals from these Cresson materials when they are exposed <br />to water and air in a cyclic contact test which is aimed at simulating exposure in the <br />natural environment. I have had the opportunity to review some of the humidity cell test <br />data for these materials as the tests were reported in earlier reports on the Cresson project <br />and some of the shorter term tests present data I have not yet seen. <br />In reviewing the acid release data for the various humidity cell samples, as reflected in the <br />pH of the effluent as a function of time, I have replotted the data in the reviewed report to <br />reflect the initial and current pH for each of the sample effluents in a bar graph format. <br />This plot is shown in Figure 3. For the sake of direct comparison with the reviewed <br />report and with the later discussion of the groups into which these materials are classified <br />by the authors of the report, the bar graph shows samples broken into these 5 groupings. <br />OMI,R951DEH <br />