HudBay Minerals has initiated full construction of its planned 3,500-mt/d Lalor underground mine in the Snow Lake district of Manitoba (E&MJ, November 2009, p. 4). The project’s estimated capital cost of $560 million is expected to fund full project development, including extension of power and water facilities to the site; a 300-person camp; surface and underground construction at the mine site, including completion of the access ramp, a production shaft and a ventilation shaft; an upgrade to the existing tailings facility; and a comprehensive upgrade of the Snow Lake concentrator.
As of July 26, 2010, HudBay had driven the Lalor access ramp approximately 800 m. Upon reaching the deposit, the ramp and ventilation infrastructure are expected to enable production of up to 1,200 mt/d of ore from the Lalor base metal zone. Initial production from the access ramp is scheduled for the second quarter of 2012, and full production from the 985-m production shaft is anticipated in late 2014.
The predominant mining method at Lalor will be post pillar cut and fill. Longhole stopes may be opened in some mine sections, depending on the thickness of the deposit. Current planning calls for production of 100,000 mt of ore in 2012; 535,000 mt in 2014; 1 million mt in 2015; and 1.24 million mt in 2016 and later years.
The upgrade of the Snow Lake concentrator will include construction of a new gold leach plant and installation of new copper and zinc flotation cells and concentrate dewatering equipment. Upon completion of the upgrade, the concentrator will be capable of processing 3,500 mt/d and will principally produce zinc and copper concentrates and gold doré bars. Metallurgical characterization of the Lalor ore is on-going; however, concentrator recoveries are currently expected to be 95% for zinc, 90% for copper, 80% for gold and 75% for silver.
Operating costs for the mine and concentrator are estimated at about $80/mt once the project reaches full production.
Based on mineralization identified to date, Lalor mine life is estimated at 15 years. The Lalor resource remains open, and HudBay is continuing to drill from surface to explore the periphery of the deposit for additional orebodies, including one drill that is targeting a copper-gold intersection recently discovered down-plunge from the base metal zone. Drilling is also ongoing down-plunge of the copper-gold zone identified in September 2009. HudBay intends to conduct extensive underground exploration at Lalor starting in 2012 when ramp access to the deposit has been completed.