QUEBEC – Toronto-based IAMGOLD has completed a feasibility study that examined the use of paste backfill in its wholly owned Niobec niobium (columbium) mine 15 km northwest of Chicoutimi. The story concludes that paste fill and other optimization projects will double the amount of mineralized material included in reserves.
Currently, ore grade material is left behind as support pillars in the mining sequence, said the company. As mining moves to deeper levels, the pillar size will need to increase. The use of a paste backfill system would allow for more complete extraction of ore-grade material from these pillars. Mining without fill is designed to extract less than 40% of the ore, while mining with paste fill will push extraction rates above 90%. The additional costs for cement and operating the new backfill system will be offset by reduced development costs and the additional mine life. Other benefits include reduced environmental impact with a smaller footprint for surface tailings containment and reduced requirements for effluent treatment as well as lower future construction costs associated with tailings disposal and management.
IamGold estimates that the project will cost $8 million. The paste fill plant and other changes could be completed in mid-2010, coincide with the start of mining on the lower levels.
Additional information about the Niobec mine is available at www.IamGold.com.