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H 1 ~, III I I I IIII III STATE OF COLORADO DIVISION OF MINERALS AND GEOLOGY Department of Natural Resources 1313 Sherman St., Room 215 Denver, CO 80203 Phone: 13031 866-3567 FAX; (303) 812-8106 January 14, 1993 Lawrence J. Corte Slurco Corporation P.O. Box 281304 Lakewood, Colorado 80228-9304 of COQ Fe •~/BT6~• Roy Romer Governor Michael B. Long Dinsion Dneclor Re: Annual Hydrology, Reclamation, and Rill and Gully Survey Reports, Canadian Strip Mine, C-81-026 Dear Mr. Corte: I have reviewed the annual hydrology report (AHR), annual reclamation report (ARR) and the rill and gully survey submitted by the Canadian Strip 1~Tme for monitoring year 1992. I have only one concern, and that is with the minor problems found during the fourth quarter pond inspections. I identify my concerns in the latter part of this review. Annual Reclamation Report The only reclamation activity conducted at the mine in 1992 was the seeding of drill pads and a portions of a road. No concerns were noted with this report. This report is in compliance with the reporting requirements of this Rule 2.04.13. Rill and Gully Survey The annual rill and gully survey, a permit requirement committed to on pages 65 c&d of the permit application, contained the information required in this section. During the 1992 annual survey no gullies were noted. No concerns were noted with this report. Annual Hydrology Report I have reviewed the 1992 AHR, with past AHRs, the Division's AHR review documents and with Canadian's statement of probable hydrologic consequence (PHC). The 1992 AHR contained the annual water level measurement for well No. 7. This well monitors water levels in the reclaimed spoils in the Pit No. l azea. The spoils water table continued to rise for the second straight year. The Canadian's AHR attributed the rise to wetter years. I graphed the water level and precipitation (enclosed). There appeared to be some correlation, but with some lag time. Only in 1988 did annual precipitation correlate well with water level. 1986 was a very wet year but this did rtot show up as a rise in the water table. Complicating the AHR's hypothesis was the reclamation of Canadian's Pit No. 2 and the open pit at the Marr Strip Mine located within 500' of the well. In the future, the influences of the Marr pit on water levels in well 7 will probably become more pronounced as the backfilling of Marr's 720 pit progresses. The backfilling in this pit will displace the water. The cone of depression caused by the pit will become a recharge mound as the water level rises.