HudBay Minerals reported in early July 2011 it will build a new 4,500-mt/d concentrator to process ore from the Lalor underground mine it is developing in the Snow Lake district of Manitoba. This change in planning results from an optimization study of Lalor development and replaces an initial plan to refurbish and upgrade the company’s existing Snow Lake concentrator to a capacity of 3,500 mt/d (E&MJ, September 2010, p. 8). The new concentrator will add C$144 million to estimated capital spending for Lalor development, bringing total estimated capital cost for the project to C$704 million.
The new concentrator will be built adjacent to the previously planned 985-m Lalor production shaft. Both the concentrator and the shaft are scheduled for completion in late 2014. While metallurgical characterization is ongoing, concentrator recoveries are currently expected to be 95% for zinc, 86% for copper, 66% for gold and 60% for silver. Construction of a gold plant, which could significantly enhance precious metal recoveries, is still under consideration.
The Lalor mine plan continues to contemplate an initial phase of production from the base metal zones beginning in the second quarter of 2012, following completion of an access ramp from HudBay’s Chisel North mine. As of early July 2011, the ramp had been advanced approximately 2,300 m and was expected to intersect the base of the ventilation shaft, also currently under construction, by the first quarter of 2012. Up to 1,200 mt/d of ore are expected to be mined from the base metal zones and hoisted through the ventilation shaft. This initial production will be processed at the Snow Lake concentrator, where it will replace production from the Chisel North mine, which is expected to reach the end of its mine life in 2012.
HudBay President and CEO David Garofalo said, “The new concentrator, with a higher production rate and related efficiencies, together with a paste backfill plant, is expected to allow for an extended mine life and to enhance the economics of the Lalor project.” On-site operating costs are now estimated at C$52/mt (C$36/mt for mining and C$16/mt for milling), down from C$80/mt under previous planning. Lalor ore production is scheduled to build up progressively from 100,000 mt in 2012 to 1.625 million mt/y from 2018 onward.
HudBay said it is optimistic that currently unclassified mineralization from the Lalor gold and copper-gold zones will be upgraded to resources following completion of exploration from underground drilling platforms that will become available following completion of the ramp from Chisel North mine and that such material will enable the extension of Lalor mine life beyond 2030.