THE TECH EDGE MMRW at Stilfontein, January 2025

The Buffelsfontein mine tragedy at Stilfontein, where at least 87 people lost their lives, underscores the complexities of illegal mining in South Africa. Nevertheless, the rescue of 246 individuals from the same perilous shaft in less than three days is a testament to South African engineering prowess.  78 bodies were recovered.

This remarkable rescue was enabled by the Tech Edge Ultra Deep Level Mobile Mines Rescue Winder – the MMRW.

Tech Edge designed and manufactured the rescue solution to be able to respond immediately to emergency situations.  The winder is mounted on an all-terrain vehicle that can move quickly from mine to mine, shaft to shaft, and be deployed without delay.

It is equipped with the world-first capability of operating to a depth of 3km.

“The Mobile Mines Rescue Winder (MMRW) performed flawlessly at Buffelsfontein and offers a glimmer of hope amidst the devastating loss,” says Russell Moore, the executive chairperson of Gauteng-based Tech Edge Group.

“The loss of life at Stilfontein is a profound tragedy that left us deeply saddened,” he says.

“Our Tech Edge MMRW demonstrated South Africa’s capacity to contribute to a safer mining future globally.”

The Rescue

On Friday, January 10, the Gauteng High Court ordered the rescue of miners who had been trapped for over three months in the vicinity of shafts 10 and 11 of the former Buffelsfontein Gold Mine at Stilfontein. The mine had closed in 2013 when its operations were no longer financially viable. The shafts had been plugged, but the ventilation shaft was reopened by the miners and access was gained in this way.

Mines Rescue Services (MRS) South Africa, the owner and operator of a Tech Edge MMRW, led the rescue operation.

Tech Edge MD Bannister Erasmus’s phone rang just before 20:00 on Sunday, January 12. On the line was MRS’ CEO Mannas Fourie, asking Erasmus to have a team on-site at Stilfontein early the next morning.

Erasmus says the ground around the shaft had been somewhat cleared over the weekend and that after on-site tests of the MMRW, the first capsule of people was brought to the surface at about midday from a depth of 1.4km.

The MMRW’s live camera feeds, from below the cage, inside the cage and on top of the cage, gave the surface team three different views of the interior of the shaft, while the communication system allowed messages to be relayed between the miners and the rescue team.

Two courageous volunteer illegal miners who had escaped many weeks ago, and who had the trust of the people underground, went down to start the retrieval.

Although the cage’s recommended passenger count is six, Erasmus says that most of the miners were so emaciated that around 11 people could be accommodated per trip.

“The relief on the faces of the miners brought to the surface was humbling,” he says.

Emergency workers were on-site to treat the rescued miners. Those healthy enough were arrested while the frail were sent to hospital under police guard.

Both Moore and Erasmus say that had it not been for the MMRW, and its ability to move on both national roads and extremely rough terrain, the rescue would not have been possible.

Despite site preparation being done over the weekend, the area remained rugged. “For any other machine to have operated on the site, a concrete foundation would first have had to be laid,” says Moore.

Tech Edge support staff – including a mechanical and an electrical engineer – were on site 24/7 to monitor the rescue system.

“The immense time spent on research and development in bringing the MMRW to fruition paid off – it worked seamlessly,” says Erasmus.

The rescue operation ended late on Wednesday, January 15.

The conception of the MMRW

The MMRW’s development was inspired by the 2010 Chilean mining disaster, where a lengthy rescue operation highlighted the need for more efficient and mobile rescue equipment.

When Moore became involved in Tech Edge in 1992, it had been manufacturing custom-made winders for the mining industry for more than 60 years. In 1993, the company’s focus shifted to pioneering solutions for the mining industry.

When 33 miners were trapped in Chile’s San Jose mine after a massive rockfall 700m underground, a standard Tech Edge winder was airlifted to the disaster site as part of Murray & Roberts’ response to the Chilean government’s call for assistance.

“Despite several countries with expert mining skills being involved in the rescue operation, it took 69 days to eventually retrieve the miners, who initially survived on emergency rations and water from a spring and radiators.

“The incident got me thinking about how a comparable situation would be handled in South Africa. I realised we needed to develop better equipment and that this equipment would need the capabilities to go anywhere – and to do so quickly,” says Moore.

“The idea for the MMRW germinated.”

Once Moore’s ideas were fleshed out by Tech Edge’s team, he took the design to MRS, who commissioned the company to complete the MMRW project.

Years were invested in perfecting the unit, prioritising unwavering reliability. Moore emphasises that the winder operates under extreme conditions, and human lives depend on its flawless performance. “To mitigate any risk, every component is designed with redundant systems.”

The winder was tested and commissioned at one of the world’s deepest mines, Gold Fields’ South Deep Twin Shafts near Johannesburg in January 2021. It was then licensed by the Department of Mineral Resources and Energy (DMRE).

Subsequently, Tech Edge developed another winder for shallower mines (1km depth capabilities), which MRS also acquired. “A similar machine was delivered to a company sinking a diamond mine in Botswana,” says Moore.

Moore and Erasmus believe South Africa needs more licensed mobile rescue units.

Design challenges

To ensure rapid deployment, the rescue winder needed to be easily transportable, capable of navigating diverse terrains, and road-legal without requiring special permits. In addition, it needed to be a self-contained system, with a power supply and sheave wheel deployment.

The winder drive and control systems are considerably more complex and sophisticated because of the significantly increased depth of wind. Rope dynamics (the movement, tension and material properties) at extreme depths necessitate sophisticated control and feedback systems. 

The end result – the MMRW – made news headlines because no mobile rescue winder in the world was able to operate at a depth of 3 000 metres.

Because it is a mobile winder, getting it licensed by the DMRE was challenging. It had to comply with the Mine Health and Safety Act Chapter 16, with some exemptions that were approved by the department.

Interesting facts and figures

• The winder is fitted with 19mm non-spin rope, and the drum allows for 12 layers of rope on top of each other.
• The sheave wheel deployment system is so novel that Tech Edge patented it.
• Because it is self-contained, no additional headgear or on-site rigging is required, saving valuable hours in rescue.
• The winder and cage are mounted on a 4×8 heavy-duty, multi-axle truck that weighs 35 tons and is 9.9 metres long.
• The rescue unit offers a choice of a one- or six-man cage, which allows rescue efforts to start before the shaft is widened, if necessary, to send down essential supplies without delay.
• The cage descends at a speed of about 1.5 metres per second.
• Although the MMRW can tap into a mine’s electricity supply, it is fitted with a 250KVa generator.

Erasmus, who himself developed another South African first, the Tech Edge mobile rope reeling system, says:

“We are extremely proud that our equipment played a huge role in the success of the Stilfontein rescue operation and are honoured to work closely with MRS, which is a top-notch organisation. The MMRW stands as a testament to South Africa’s capacity to develop world-class solutions and contribute to a safer future for miners worldwide.”

The catalyst for the design of this innovative equipment was the 2010 mining accident at Chile’s San Jose gold mine.

MMRW: A Game-Changer in Rapid Underground Rescue

South Africa was one of the countries to contribute to the relief efforts, including airlifting a Tech Edge standard winder to San Jose to act as standby to the efforts of the Chilean authorities. This incident brought together some of the best global mining safety experience from South Africa, Latin America, Australia, the United States and Canada, but also highlighted critical issues in the technology available to speedily mobilise and implement relief efforts. .

This prompted us to design a mobile, go-anywhere, self-contained rescue winder specifically designed to address the need for rapid response, deployment, and resolution of underground mining emergencies; the MMRW.

We offered the concept to South African Mines Rescue Services, who contracted Winches & Winders to bring our MMRW design to life.  

We started development of the MMRW as soon as we could following the events in Chile in 2010, and it has taken 9 years of design finessing and testing for us be totally satisfied with the product. Research and development of a revolutionary new product is expensive and time-consuming and had to fit in with our regular winder manufacture. We also wanted to hone the design parameters to ensure that, when completed, the MMRW would be world class.

Realising the urgent need for increased mine safety, we stuck to our task as good engineers do.

Unique considerations or challenges:

The design brief was specifically engineered to improve mobilisation and efficacy of rescue efforts, including: 

• Rough terrain capability for off-road and rural access
• A self-contained system, including power supply and sheave wheel deployment
• Normal height vehicle so no additional road permits are required 
• All normal statutory requirements for man-riding mining conveyances.
• Length of wind allowing first responder teams to carry out rescue operations to depths of 3km.

This is the greatest depth, by far, to which any rescue winder can operate, worldwide.

The developed specifications were, at times, difficult to resolve in one design. Our aim was to design a solution that will give rescuers an advanced, efficient, widely applicable solution. This meant developing ideas that balanced engineering invention and solid pragmatism.

One of the most exciting elements of the MMRW is the sheave wheel deployment system, which is so novel we patented it. The self-contained sheave wheel means that no additional headgear or on-site rigging is required at the rescue site, saving valuable hours in rescue operations. 

The MMRW needed to be deployable in most terrains, including normal roads, so we needed a non-permit vehicle. This was a challenge as there is some serious equipment mounted on the truck, but our engineers managed it through careful truck selection, balanced loads, and persistent design evolution. 

Also included in the design are the one- or six-man conveyances (the cage that attaches to the end of the rope). This means rescuers can select their conveyance depending on the size of the rescue shaft and can begin rescue efforts with the much narrower conveyance before the rescue shaft is widened. Again, this saves valuable time when retrieving people trapped underground or delivering essential supplies and equipment during rescue operations.

The winder drive and control systems are considerably more complex and sophisticated because of the significantly increased depth of wind. Rope dynamics (the movement, tension, and material properties) at extreme depths necessitate extremely sophisticated control and feedback systems. 

With more than 80 years of operation in the international mining industry, we pride ourselves on our innovation and excellence in engineering. Our Mobile Mines Rescue Winder or MMRW, is truly the culmination of those ideals.

We continue to work on engineering solutions to improve health and safety in mines.