1989-12-01_REVISION - M1988112 (4)

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14. Pg. D-23: "The tailings disposal site is located immediately adjacent to a topographic saddle near the midpoint of a dry drainage tributary to Culebra Creek." This 192 acre site is located in a sandy loam area subject to contamination of the aquifer due to percolation of solutions. Further, the site IS IN THE RITO SECO DRAINAGE which eventually leads into the Culebra Creek. BMIG must provide monitoring wells in the groundwater, with frequent testing. Several wells should be placed downgradient, with at least one 'baseline' well above the mine site. 15. Pg. D-24: The drainages in the 192 acre tailings disposal site will, upon reclamation, be rerouted across the reclaimed tailings surface. This plan will cause the possibility of leaching of metals and other substances by surface runoff. In the long term, the concentration of heavy metals and other pollutants will increase in the San Luis community. This is a dangerous legacy for the town to be saddled with forever. Surface waters should be permanently diverted around the tailings site to prevent heavy metals, pollutants, and silt from washing into the Rito Seco drainage. A long-term monitoring program should be required at the mine site after completion of the mining and closure of the operation. This should include surface and groundwater testing, and a plan for corrective action if acid or toxic leakage develops. Guaranteed funding for these steps should be required before the MLRB grants this permit. This is to insure that neither the community nor the state be burdened with the costs of cleaning ~p after the mining company is gone. These funds are above and beyond the reclamation bond which BMG has agreed to. 16. [D.6.4.3] What amount of volatilization of cyanide can occur at the "tailings beach"? What will be the cyanide forms which can be expected to remain or be evolved? 17. Pg. D-29: What are the results of cyanide volatilization as per "The results of this testing program will be submitted within two to three weeks to the MLRD for incorporation in the document review process"? 18. Pg. D-31: The Liner System is inadequate as only a single liner is provided. A double or triple liner system should be required. Water from the tailings drainage constitutes an imme~iiate danger to the community should a spill or leak occur. In the ling term, the leaching of substances into and under the community i~ of grave concern. 19. Pg. D-32: "Limited leakage" due to installation of t.ie geomembrane must not be allowed to occur. The "level of redund:3ncy which reduces the risk of leakage" is not sufficient. The chan~:es of liner rupture due to road traffic are almost a certainty. Tie plan is too dangerous for this community to accept. -3-