Kiwi case
In New Zealand, Solid Energy’s Huntly East, which utilizes continuous miner development with secondary extraction, has adopted a comprehensive escape system. The mine also has three permanent refuge chambers – called changeover stations – with dedicated boreholes to the surface and compressors to provide breathing air. It also integrated a portable 20-person MineARC refuge chamber into its escape system. “Similar to the United States, the Huntly East miners are equipped with one hour duration SCSR.
The decision to purchase a refuge chamber was to ensure a practical self-escape plan from workings 3 miles from surface. It was felt that it would be unlikely that a worker could escape in impaired visibility with the limitation of 1 hour of oxygen in the reasonably steep changeable grades worked in,” MineARC Systems America manager James Rau said.
The mine runs lifelines the full length of the mine’s main intake and returns with directional cones to get miners to each of the three permanent changeover stations and the portable MineARC chamber.
MineARC’s refuge chamber is located in the non-restricted areas of the mine, one reason being that it is not intrinsically safe.
It is generally located 500 feet from the face but regulations would allow 300ft back from the last cross-cut.
Huntly East advocates an “escape if possible” strategy via normal transport.
However, once miners encounter impaired visibility, the escape is staged via the three chambers provided on the main traveling road. They are spaced at approximately half a mile to a mile apart. The chambers allow rest, communication with surface (via normal communication network or a direct independent feed to surface up the borehole) and a safe environment to changeover a self rescuer for a new one.
Poised to supply
Many refuge chamber design and manufacturing firms are currently waiting in the wings with their products for the Mine Safety and Health Administration to issue guidelines so their chambers can be certified for underground coal mines.
MineARC Systems are one of these companies that have made several trips this year to safety symposiums, conventions and meetings in order to ascertain US requirements. MineARC has also been using its 12-year history in the business to advise industry leaders and promote its range of refuge chambers.
Currently few guidelines exist for refuge chambers, however, the Australian metalliferous industry has one of the most comprehensive in the Western Australian Refuge Chamber Guideline 2005. The guideline was developed after industry acceptance of standards already set by mining companies and manufacturers.
According to Rau, “it seems that the US industry will follow a similar pattern with industry acceptance than a guideline to follow”. This has already commenced with numerous mining companies enquiring after MineARC’s Refuge Chambers with specific options and modifications to suit the US mining regulations. Many metal and non-metal mines and some coal mines are taking a proactive safety stance by requesting information and pricing on refuge chambers whilst some have already committed to purchasing.
MineARC’s refuge chambers are the only system to have scrubbing for both carbon dioxide and carbon monoxide. The carbon monoxide is a patented system for endogenously produced carbon monoxide from cigarette smokers who exhale quantities of carbon monoxide when in a sealed environment.
The chamber’s control system allows a one-touch emergency operation, programmable maintenance functions and the ability to remotely monitor the refuge chamber from the surface with photographic imaging and real-time readouts (using data cable and access codes over the internet).
The company is currently supplying chambers to the US hard rock mining industry from its new Dallas manufacturing facility and is a leading supplier to the industry in Australia as well as Europe, Canada, Chile, Indonesia, Ireland, Turkey and Hong Kong.
