1992-06-16_REVISION - M1988112 - Laserfiche WebLink

Home Browse Search

• III IIIIIIIIIIIII III r BATTLE MOUNTAIN NORTH AMERICA iNC. A NDRE I. DOUCHANE rarsini~~r By Facsimile Message June 12, 1992 Dr. Harry Posey Mined Land Reclamation Division 1313 Sherman St. 215 Centennial Building Denver, CO 80203 Dear Dr. Pendleton: ILE MOIRJiAIN D COMPANY ~~N i s 1992 `~unEC ~erla,.,,, ~gi1L •inn n• '`''n Additional responses to comment #3 and #9 by Dr. David Hyatt are listed below: Comment #3 To expand and clarify our response to keeping the pond active, there are also other valid reasons for maintaining the processing. Cessation of tailings deposition will result in a stagnation of the system, greatly minimizing cyanide degrada- tion of the existing tailings. During active tailings deposi- tion, the pond and tailings flow will be maintained which will enhance mixing and the mass transfer of cyanide from the solid tailings to the liquid pond. If tailings deposition ceases, the pond will slowly evaporate and in effect "dry out" the tailings. This drying effect will retard the detoxification of cyanide trapped within the solid material. continued 3eposi- tion with hydrogen peroxide-treated tailings will lead towards a cyanide equilibrium between the solid and liquid phases in the impoundment. Additionally, liquid entering the impoundment with the tailings slurry will be detoxified with hydrogen peroxide. The detoxified liquid will migrate through the existing tailings and in effect rinse cyanide trapped in the solid material. All solutions passing though the solid tailings will be collected in the drain layer and gravity flow to the seepage collection pond. From the seepage collection pond, the liquid will be returned to the mill for re-use in the process. The recycling of tailings solution through continued milling and tailings deposition will hasten the flushing action 5670 GREEN WOOD PLAZA BLED. SUITE 106 ENGLEWOOD,CO 80111 (30J)72Ifi744 FAX (30J)72I {g l3