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Ms. Christine E. Johnston 1992 AHR Response August 25, 1994 Pagz 6 5. In 1992, imported water and inflow was 68.2 acre feet, while mine inflows were 5 acre feet on production of 1.38 million tons of coal. The Probable Hydrologic Consequences was written to accommodate the permitted production and estimated inflows of approxitna[ely IS acre-feel from 2.8 million tons/year production from the B seam, therefore, as the pretlic[ion of inflow roughly approximates the observed inFlow, MCC declines to modify thz PHC. 6. There appears to be no question for number 6. 7. There appears to be no question for number 7. 8A. MCC is proposing a modified monitoring program in conjunction with this submittal which would result in the acquisition of one full suite sample per sift, pzr year. With this changz in the monitoring program, the listing of the extremes as well as the means are no longer a part of the program and will be deleted from future AHRs. This was used for the indicator species and will be replaced by the revised monitoring plan. Appendix E was designed to pzrmit a comparison of the year's water monitoring data with baseline values, to ensure compliance with the monitoring commitment to reanalyzz samplzs that fell outside the range of extremes. MCC declines to list the mean value, as there would be no justification for it within [he context of Appendix E. 8B. MCC does not believz that any measurable diffferences or meaningful data can be obtained by establishing a Flow monitoring gage on the North Fork of the Gunnison at the lower station, given the size of the river. Furthermore, i[ is not economically feasible to establish such a gage. Thz monitoring plan was designed assuming that the Flows at the two sites wire adequately similar [o allow the use of [he upper station's flows at the lower site. 8C. Appendix E is restricted to reporting the results from the three surface water sites on [he north side of the Minnesota Cteek drainage divide. Mining has not occurred below the arias reFlected by the other surface water monitoring sites. The silts south of the divide art still collecting baseline data. 8D. Appendix E for the 1993 AHR has been revised and is enclosed herein for replacement of the existing Appendix E. It currently includes the dates the minimum and maximum values were recorded. 8E. Please refer to [he revised Appendix E for the minimum and maximum TSS values for GP-1. 8F. The minimum and maximum values reported in Appendix E of the 1993 AfiR are based on pre-disturbance baseline data. In some cases this consists of data acquirzd prior to [Wining or dis[urbancz, and in other situations it consists of the first twelve months of data collected at the site. The source of all data points have been extensively documented. Thz minimum and maximum values presented in Appendix E, Comparison of Baseline Minimum and Maximum Values for Surface Water, Spring, and Groundwater monitoring Parameters with 1993 Values, for the Water Year 1993 report, art those minimum and maximum values recorded during associated baseline monitoring periods as reported in the Annual Hydrology Report, Mt. Gunnison No. I Mine, Water Year 1989 (as supplemented by information provided in Appendix E of the Water Year 1993 Report).