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Inspection and Maintenance of Shafts and Mine Cages are Essential

Mining companies specializing in underground mining know that each mine is unique as each deposit has its own set of geologic, geochemical, and geophysical characteristics. The same holds true for mine shafts and mining cages and, though they are built in accordance to applicable standards and regulations, they are ultimately designed to meet the needs of the operation and the site.

Mine Cages

Lack of Inspections can Result in Lost Revenues

Regardless of how shafts and cages are built, they are subject to the forces of gravity, corrosion, and age. Ignoring the effect of these elements can cause an unplanned shutdown, which can have a negative economic impact on an underground mining operation.

A Mullan, Idaho mining site, for example, was ordered to be closed a few years ago after the discovery of an accumulation of dirt and concrete material in the shaft. The site was on maintenance status for a year, and the mining company responsible had to spend over US$30 million on shaft rehabilitation alone. The company also lost an estimated US$135 million due to unrealized silver, lead, and zinc revenues.

“Chairing the Cage”

Only recently, a Canadian mining company was ordered by the Ministry of Labour to incorporate daily mining cage inspections. In their decision released in April, the Ministry ruled that inspections of the safety catches on mining shaft elevators must be done daily, a process often called “chairing the cage”. Failing to do so compromises the safety catches, or the dogs, rendering them unable to spin or bite into the wooden timbers found in the shaft and stop any free-fall.

The same requirement for mining sites has also been declared by the Occupational Health and Safety Act, which requires these dogs “to be examined for any defects on a daily basis.” This is due to the fact that a dog can seize in less than a week, endangering workers and creating higher risk for an unplanned shutdown.

More Streamlined Inspections

Some companies have been utilizing technology for more streamlined inspection processes. One particular inspection system made use of lasers, Global Positioning System, and Inertial Navigation System, to allow for the inspection of mine shafts without interfering with production.

Such technologies can further ensure that mine operations are continuously operating efficiently. It’s also important for mining companies to work with equipment manufacturers, like Wabi Iron & Steel Corp., to ensure that they acquire customized mine cages to suit their individual needs.

Scaling-up Shaft Safety, Engineering and Mining Journal
Mining company loses fight to skip daily cage inspections, Northern Life