When one hears about a mine collapse in Ghana, it’s usually a galamsey operation – deaths in an illegal small-scale mine dug by impoverished semi-skilled amateurs. Ghana is riven by galamsey, with about a third of its sizable gold production clawed by hand from shallow pits.

The collapse that killed six men and injured four others last week at an Ahafo gold mine was anything but galamsey. Newmont Mining Corporation, the world’s second-largest gold producer, has a $20 billion market capitalization and mines more than 150 tons of gold every year. The Ahafo mine alone produces about 350,000 ounces annually.

Would the availability of drones have been able to help mitigate this disaster?

Ghanaian mining officials are still investigating the cause. Two men were pouring concrete at a reclaim tunnel while eight others worked in the tunnel when everything collapsed. John-Peter Amewu, minister for lands and natural resources, described the accident as a “complete structural failure” the day after the disaster.

“You realize that during the process of casting the concrete, the concrete caved in. Investigations are still going on but it’s clear that the prop that supports the slabs might not be well placed and that could trigger stresses that enabled this slab to cave in,” he said.

The Ahafo Mill Expansion project meant to restore the depleted mine to productivity. Instead, for now the expansion project sits idle amid calls for increased regulation, unannounced inspections and compensation for the families of the dead.

Here, it is certainly worth investigating how drones become useful tools to help prevent future similar incidents from taking place. Swedish manufacturer Inkonova produces a specialized drone for underground scanning in dark, cramped spaces. It records and transmits a 3D laser pointcloud map as well as video footage. The pointcloud map can be used as it is, converted or processed to extract vital information for the mine or facility managers. In Switzerland a new firm, Flyability, makes a flying drone with a thermal camera built for underground use. It flies in a geodesic roll cage, allowing it to be recovered after a crash.

Systems like these could be used to inspect the supports for a shaft, allowing a skilled remote operator to take the place of an inspector. A drone in a mine might take snap-shots of the mine’s walls weekly, daily or even multiple times a day. Software might then analyze the images to see if any changes are noticed that can be a symptom preceding collapse.

Some of the power of unmanned surveillance and autonomous vehicle use depends on the general competence and technical proficiency of the enterprise. Consider that Brazilian miner Samarco had been using aerial drone surveillance to watch a tailings dam, which subsequently broke, sending an avalanche of toxic mud to destroy a village, killing 19 and displacing hundreds. Mud reached the Rio Doce river, killing livestock and poisoning the water supply. Police charged 22 people with crimes ranging from environmental damage to homicide.

Samarco’s problem wasn’t the quality of its electronic monitoring. Samarco claims that the collapse could not have been predicted. Prosecutors alleged recklessness. In either case, the use of drones alone would have been insufficient – powerful observational technology and analytical tools must be backed up by rigorous incident planning to be effective.

At Ahafo, Newmont notes that it has site-based personnel trained to handle emergency response management and procedures on site, working on a 12-hour shift system. As the roof of Newmont’s mine collapsed, the men below found themselves in a pool of quick-setting concrete spilling from above.

Newmont’s local contractor, Consar Limited, immediately dispatched an emergency recovery team after the accident, rescuing two of the eight workers below when the collapse occurred, said Okeyere Yaw Ntramah, acting general manager of the Newmont mine at Ahafo. It took another 14 hours to recover the bodies of the remaining six miners.

Other unmanned technology might be employed in a rescue. For example, Montana Tech is developing a rescue drone for mining. Military bomb-handling robots from Remotec and research universities in Australia have also been developing autonomous vehicles for mine rescue. Coal mines present greater rescue challenges than non-coal mines because of the presence of hazardous gasses, but the principles would be the same – an unmanned vehicle that can perform search operations in the dark, detecting possible hazards and looking for the injured and the dead.  

Drones and autonomous vehicles allow for fast searches without increasing the risk for the rescuers or victims, note researchers from the National Institution of Technology Karnataka in India. A rescue robot could create a real-time 3D image of the space in a mining collapse, to be transmitted to mobile devices used in tandem by human rescuers. Equipped with thermal and laser sensors, a drone could also find an optimal path through debris and warn of additional instability, and more easily find personnel. The Gemini Scout robotic rescuer under development at Sandia National Laboratories fits this profile.

A paper by Accenture published at the World Economic Forum last year estimated that about 120 miners lives would be saved and approximately 7,000 injuries avoided over the next decade with the use of autonomous vehicles.

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