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sii iuiiiiiiiiii iii GRAND VALLEY COAL COMPANY P.O. Box 70 Loma. Colorado 81524-0070 (970) 858-3608 FAX (970) 858-7690 ,; RECEIVED October 11, 1997 Mr. Dan Mathews Division of Minerals & Geology 2148 Broadway; #C-5 Grand Junction, CO 81503 Re: Munger Canyon Mine; CO-81-020 Response to Permit Stipulations Dear Mr. Mathews, r. `; ~p~7 ti~ ~ - ~N~wnGrand Junction logy The following responses are submitted to address the Division's Permit renewal stipulations for the Munger Canyon Mine. Simulation 24 - Requires GVC to submit revised permanent channel designs with 0.3 feet freeboard and rip rap specifications. The designs submitted on Table 3.9-3 have been revised to show a uniform channel depth of I.5 feet. All channels will have about 1.3 feet of freeboard. Other designs, shown in Table 3.9-5 include provisions for adequate freeboard. A new Table 3.9-3 is being submitted to replace the previous Table 3.9-3. The design of the channels utilized the velocity limiting method to ensure non erosive velocities within the channels. Therefore, no rip-rap will be necessary to ensure channel stability. Figures 3.9-6, 7 & 8 have been revised to indicate that no rip rap is necessary. Simulation 25 - A textural analysis was conducted on the coal that is stored at the Loma Loadout. The analysis is included and should be added as Page 15 of Table 3.9-4 . The analysis was performed on a composite sample collected from about 50 locations and indicated that only about 11.4 % of the coal is less than 0.25 mm. No revision the material strength parameters used to calculate slope stability is necessary. Also included with this revision is the road compliance statement that should be added to Appendix O. Please advise me if you have questions or if I can be of assistance. ~~ John M. Walters Manager of Mine Services