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s- be an interim measure for waste rock control, field results from which were to have provided information on the possible need for overburden capping in the post-mining setting. Whether the 0.390 S presumption was used in calculatibns of overall NNP predictions is not evident from the text. Unless the presumption that rock with G0.39o sulfur was etsed to characterize NNP calculations for surface or groundwater, it could be removed from the text. If the Operator has used the assumption itt any ARD predictive context, the statement should be verified. 2. Page 22. The AGP formula indicates that 6790 of the sulfur was sulfide sulfur. The footnote, indicates 6990. Please clarify x•hich sulfide sulfur value is the correct percentage of total sulfur. Please indicate how the 6790 (or 693'0) value was derived. 3. Page 21-26. The articulated comparisons between blast-hole NNP, humidity cell, and static test NNP results are confusing and in cases are not accurately reflected in the accompanying diagrams. It appears that the 38 humidity cell tests are interpreted to represent the AGP & ANP data provided by the more than 100,000 samples from the currently mined area, but as the average NNP's of the two data sets differ, this presumption seems questionable. It is presumed for purposes of this comment that blast hole test results would provide more representative information on C:S ratios of the mined interval. The discussion in the top paragraph of page 25 does little to clarify the explanations. (a) The discussion on page 23 (3'" paragraph) refers mostly to Figures 4-2a and 4-2b and indicates that, based on the final pH of the humidity cell tests, "the AGOSA can be expected to generate circum-neutral leachates" The text indicates that the "average characteristics" would indicate a neutral pH, even though only about I/3 of the samples have a pH greater than 5. (b) The discussion on page 23 apparently projects the NNP for all of the waste rock, but the figure does no[ distinguish between AGOSA waste rock and SGOSA waste rock. Evidently, data in Figure 4-2a were meant to be repeated in 4b, but about 15 of the sample results appear to be missing from 4-2b. (aJ Please clanfi~ how it x•as concluded that the overburden "can be expected to generate circum-neutral leachates. " if clarificatiau or corrections ojfigures 4-2a and/or 4-2b are necessary to explain the conclusion, please include those. (b) Please distutgi« sh on figures 4-2a and 4-26 x•hich samples represent AGOSA and which represent SGOSA. Please indicate x hetlter these are representative of the rock that xil(be encountered in future mining. (cJ Please explain the possible discrepancies between Figures 4-2a grid 4-26 or submit corrected figures. A. Pale 25-26; Vol. II. Figure 4-4; page ?6-,7.