Contents of Engineering & Mining Journal - FEB 2012

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

Page 45 of 83

SAFETY
"The most dangerous situation underground is fire, and although the potential causes of fires may have changed, the critical scenario remains."
toxic gas can overcome a person faster than they can try to escape from it, the obvious—and increasingly widely used— solution is to bring safety to the miner, rather than have the miner try to reach a place of safety on his or her own. A number of companies have devel- oped mine refuges, initially for use in coal but with a rapidly accelerating take- up within hard rock mining as well. For example, the Australian company, MineARC, offers both mobile and perma- nent mine refuges that are designed to keep trapped miners alive until they can be rescued, and reports in its latest newsletter that an increasing number of mines are now installing and equipping permanent chambers that can offer secu- rity for larger numbers of people than was previously the case. MineARC's moveable hard rock mine refuge chambers are available in four, eight, 12, 16, 20 or 26-person capaci-
ties, with the company noting it can also design custom models to meet individual needs. Its refuges are built from 5-mm (¼-in.) steel plate, and are equipped with three sources of breathable air sup- ply, initially from the mine air supply- system. Should this connection be lost or contaminated, medical-grade oxygen cylinders and oxygen candles continue to supply air for a minimum of 36 hours. Air conditioning maintains a comfort- able temperature inside the chamber, with carbon monoxide and carbon dioxide being scrubbed from the air inside it by active chemicals and MineARC's patent- ed electrical scrubbing system. Digital gas monitoring constantly alerts occu- pants to the levels of dangerous gases in the chamber, which also has a back-up battery system that can power its internal life-support systems for a minimum of 36 hours should the mine's main power sup- ply be lost.
MineARC also reports it has recently seen a large rise in the number of mines world-wide that are installing its perma- nent hard rock refuge chamber technolo- gy, with seven units having been com- missioned in the past few months in Australia, Turkey and the Philippines. These refuges have been built in both new and existing excavations, and are often doubling as lunch rooms, the com- pany adds. Permanent refuge chamber offer a practical alternative to standard 'portable' refuge units, and have advan- tages where refuges do not need to be moved regularly, or where large numbers of miners might need to find safety. In this context, MineARC's permanent refuge technology can sustain up to 150 or more people in a single confined space. Recent installations include two 80-person lunch rooms at Argyle Diamond Mines' new underground opera- tion in Australia, while in Turkey, Inmet Mining has installed two 30-person sys- tems at is Cayeli base-metals mine. Other companies with MineARC refuges in- clude BHP Billiton, Newmont, Xstrata, Barrick Gold, Newcrest Mining and Freeport McMoRan Copper & Gold.
44 E&MJ; • FEBRUARY 2012
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