In many industries, machines are taking over jobs that humans used to do. Hands-on human involvement in mining is however here to stay and can guarantee improved mine safety.

Quite apart from socio-economic and political factors, some mining environments simply do not support automation of all processes, and mine workers are needed to perform critical tasks such as blasting and removing rock from the rock face.

Extremely dangerous jobs, such as working in the stopes, require technology that keeps mine workers out of harm’s way. A team from the Faculty of Engineering on the Potchefstroom Campus has been digging deep in the platinum mining industry, seeking technology solutions that simultaneously improve mine safety and productivity.

This is no easy task, says project leader Prof Johann Holm. “One has to deal with extreme conditions underground and electronic equipment is subjected to extreme heat, shock, vibration and abuse.”

The art of designing effective safety solutions lies in the engineer’s ability to understand all aspects of operations, especially the human side, he says. “Humans are known to cause more than 90% of all failures. This makes South African mines a particular challenge for a safety product developer, and any methods and techniques that can assist in building more robust products will add value.”

Warning system secures safe crossings

One of the most robust products introduced in recent times is a particularly successful winch signalling system used in the stope environment where the rock face is blasted and worked on daily. Prof Holm’s team did the research behind the new signalling system, which was developed in conjunction with V&S Mining Supplies. It is used to warn miners before scraping commences in a centre gully from which strike gullies emanate.

“Miners remove platinum-bearing ore from the strike gullies to the centre gully and sometimes have to cross these gullies,” he explains. “Crossing a gully without prior warning is a daunting affair since the winch operator does not have a view of the gully when scraping. The miner must have a means to signal to the winch operator before a crossing and must be able to trip the scraper winch in emergency conditions.”

The signalling system fits the bill because its warning signals can be seen and heard, it is effective in emergencies and it makes use of highly robust electronics, cabling and mechanical devices capable of withstanding the extreme conditions underground.

“The impact of a blast is incredible, and the sensitive electronic equipment has to withstand shock waves from blasts that are sometimes less than 20 m away,” Prof Holm says. “Added to this are high levels of humidity, temperature and corrosion.”

Communicate well

The winch signalling system has been dubbed Khuluma Kanjaan, which means “speak” or “communicate well”, and has been well accepted in the mining industry. What makes it so effective in underground communication is the depth of research that went into its development. “It was developed following a systems engineering approach with the focus on activity-based risk,” says doctoral student Rossouw van der Merwe, who is writing system.

“Using this activity-based risk framework, we simulated various system scenarios and determined the risk impact – for both production and safety risk – of each activity. This made the high-risk activities visible, which in turn allowed us to address these activities in the system design.”

The methods and techniques used in this study have since been successfully applied to develop more systems, including systems outside the mining environment. Tried and trusted in the extreme conditions found in mines, it’s a safe bet that such systems are on solid ground.

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