In the world's #1 mining jurisdiction sits Brunswick 12, the world's largest underground zinc mine slated to close in 2013, near Bathurst, New Brunswick. Operational since 1964, it has hosted a cumulative output (up to 2005) of over 110 Mt of ore.
With approximately 800 employees, Brunswick treats 3.6 Mt of ore per year from 10 separate massive sulphide lenses containing zinc, lead, pyrite and copper zones, and including gold, silver and other metals.
If the familiarity of the geological structures doesn't get your ears ringing, the reserves might:
At the end of 2009, proven reserves totalled 6.2 Mt grading 0.4% copper, 8.4% zinc, 3.4% lead and 104g/t silver. The probable reserves stood at 2.2Mt grading at 7.6% zinc, 3.0% lead, 0.3% copper and 84g/t silver.
Improved extraction technology has lengthened the productivity of the mine, which is good news for explorers and future operators in the area. Originally expected to be depleted by 2010, the implementation of a zinc circuit stabilization project leading to a 4% increase in zinc in concentrate has made it economic to continue the Brunswick 12 project into 2013.
Other advances there which have increased production economics are an upgraded mill to increase grinding performance and the commissioning of a paste backfill plant to simplify the backfilling process underground.
The company ships the copper and zinc concentrates to worldwide markets as raw concentrates. Lead and bulk concentrates undergo further refining in the company smelter at nearby Belledune, a deep seaport. The smelter separates out copper matte, antimony-lead alloys, silver-gold doré and bismuth alloys in successive steps.
The Brunswick 12 mine is located 35 km southwest of the town of Bathurst.
Active in the area are Trevali Mining Corp., a current zinc-lead-silver-copper producer at its Halfmile Mine, which is ramping up production rates to 2000 tonnes per day this year, and Votorantim Metals, currently developing the Murray Brook deposit.