Brunswick is one of the world's largest underground zinc mine. The mine is located on 1,030 hectares of property in northeastern New Brunswick, Canada, 20 kilometres southwest of Bathurst.
Zinc concentrate is shipped by rail to CEZinc, in Valleyfield, Quebec or shipped offshore either to the Xstrata Asturiana zinc smelter or to other smelters in Europe. Bulk concentrate is shipped to a variety of smelters in Europe. Lead concentrate is shipped by rail to the Xstrata Belledune lead smelter. Copper concentrate is shipped by rail to the Xstrata Horne copper smelter, in Rouyn-Noranda, Quebec.
There are 800 employees at the mine and another 400 at the Belledune smelter. Production and maintenance personnel work two shifts per day. The mine operates seven days a week.
The mine is located on 1,030 hectares of property in northeastern New Brunswick, Canada, 20 kilometres southwest of Bathurst.
Bathurst and the surrounding area have a population of about 30,000. Bathurst itself is a small city with a population of 13,000. It is well connected to the rest of the country -- by road, rail (Via Rail), and air (Bathurst Regional Airport).
The Brunswick ore body is hosted in steeply dipping volcanic and sedimentary rock units. The deposit comprises massive sulphide associated with various iron formation facies. Zinc, lead, copper and silver are the principal metals produced. The host rocks and the mineralization have undergone four significant deformation events, resulting in intense folding and faulting.
Most deposits are zoned vertically and laterally from a high-temperature, vent-proximal, Cu-Co-Bi-rich veined and brecciated core to vent-distal Zn-Pb-Ag-rich hydrothermal sediments. The vent complex is commonly underlain by a highly deformed sulphide stringer zone that extends hundreds of meters beneath deposits and consists of veins and impregnations of sulfides, silicates and carbonates that cut chloritized and sericitized volcanic and sedimentary rocks.
Exploration is taking place to find a new mineral deposit near the existing Brunswick mine site. 13,000 meters of drilling were completed in 2006. The drilling program did delineate favourable geological horizons similar to the Brunswick ore bodies.
The mining method is open stoping with pillarless, pyramid-shaped open stope sequences and end-slicing. The mine has developed significant ground-control problems, including ground support of development, failure and dilution of hangingwalls and seismicity and rockbursting. Advanced mining equipment such as the Weasel, a remotely-controlled unit, drill blast holes and load charges. Remotely controlled front end loaders and trucks remove rock from blasted areas.
Ore is crushed underground and raised to surface for transport to the nearby concentrator. Voids are filled with paste backfill. Paste backfill and binder contents of fill for fill mats have been designed to stabilize vertical heights.
Major mining equipment includes Wagner LHDs and mine trucks, Montabert hydraulic development jumbos, Tamrock pneumatic development jumbos, MTI and Cubex ITH 5200 in-the-hole drill rigs, Boart Longyear longhole drills, Secoma rockbolting jumbo, Tamrock Solo 606 top-hammer drill, Atlas Copco cable bolting rig, Atlas Copco Robbins 34RH raiseborer, JKS Boyles diamond drills.
Processing in the concentrator removes gangue and leaves commercial components: lead, zinc, copper, silver, gold, bismuth, antimony and cadmium.
Ore is ground to a powder in the semi-autogeneous grinding mill, mixed with frothing agents, followed by differential flotation, filtering and drying. The products are lead and bulk concentrates, copper concentrates and zinc concentrates.
Copper, zinc, and bulk concentrates are shipped to market while lead concentrate undergoes further refining in the company smelter at Belledune, New Brunswick, which is 30 minutes northeast of the mine, at a deep-water port on the Atlantic Ocean. The smelter separates out copper matte, antimony-lead alloys, silver-gold doré and bismuth alloys in successive steps.
Key customers of the mine are the Brunswick smelter for lead concentrate, the CEZ refinery for zinc concentrate, and the Horne smelter for copper concentrate.
Flotation tailings are sent to the paste backfill plant for recovery to produce paste backfill for the mine. Residual tailings are sent to the tailings impoundment facility.
Process water is recycled back to the concentrator while the excess runs through an effluent treatment facility before being discharged to the environment.