The hunger for metals and minerals, driven by a growing global economy and the digital and renewable energy sectors, is insatiable. Meeting the surging demand for resources like copper, cobalt, lithium, and gold may require Africa to dig even deeper than it already is.
In terms of natural resources, the African continent without a doubt is one of the most well-endowed regions in the world. It therefore has some of the deepest mines.
Extending a whopping 3.9 km beneath the earth’s surface, over ten times the height of the Empire State Building, AngloAshanti’s Mponeng underground mine in South Africa tops the list. Situated on the country’s West Rand, the site – together with tailings dump-retreatment operations and rock dump reclamation and processing activities – accounts for 13% of AngloGold Ashanti’s total annual production.
Next on the list are Harmony Gold’s Kusasalethu (3.38 km), Driefontein owned by Sibanye-Stillwater (3.3 km) and Moab Khotsong (3.1 km), also owned by Harmony Gold. These are followed by Gold Fields’ South Deep underground mine operations (3 km) near Johannesburg.
As the term suggests, underground mines like the ones mentioned above go deep into the ground. Open pit operations, on the other hand, involve digging the ore from the open ground in quarry-like sites on the surface. Some open pit mines, when exhausted, may be extended underground depending on the type and grade of the resource. This is done by sinking vertical shafts, with their visible headgear above ground, or by building spiral tunnels that circle around the reserves. Sometimes, adits or horizontal excavations are created into the side of an ore-containing mountain to access the deposits.
Whilst gold dominates the world’s deepest mine spectrum, other resources are catching up. Take copper. The Mindola copper mine on the Zambian Copper Belt is one of the deepest of its kind in southern Africa. Plans exist to increase its depth from 1330 m to 1590 m. In the meantime, there is the Mufulira Deeps by Mopani Copper Mines, which is currently under construction. Once the shaft reaches its design depth of 2 km, the site will be the world’s second deepest single-shaft underground copper mine in the world, after Resolution Copper Mine (2.1 km) in the USA.
The latter development will help Zambia increase its annual copper output by a predicted 4.5% per year between now and 2027. “As a result, we expect the country to jump from the tenth-largest refined copper producer in the world to eighth largest over the same period,” a recent BMI Research report shows.
Michal Kotzé, head of PwC South Africa’s Africa Energy, Utilities and Resources division, is not surprised. “The growth of the global economy and high levels of industrialisation require copper. Copper is here to stay, also because there are no substitutes for the metal. Zambia will remain a key supplier of finished copper,” he says.
The growth of the global economy and industrialisation require copper. Copper is here to stay
This growing demand may result in deeper copper mining operations. This, however, depends on several things, including the characteristics of the specific ore body and the grade of the resource. This determines the value. “The deeper you go, the more expensive it is to mine,” Kotzé says. “It needs to remain financially viable.”
Going to greater depths to reach valuable metal and mineral reserves is, however, not without risk. Mining companies in Africa, Zambia included, are aware of the risks of deep mining and are trying as hard as they can to rule out accidents. In July this year, copper mining company Konkola launched its Safety Stand Down campaign to address accidents in relation to their commitment to increase production to 400 tonnes a day. “Even when we are pushing to achieve that production target of 400+ tonnes, the first thing on my mind, as a priority for KCM, is safety. It should also be the first thing in your minds. We cannot have production if it does not come safely. When there is a fatality, it hurts and devastates everyone,” CEO Deshnee Naidoo said during the campaign’s launch.
Kotzé notes that mining companies’ awareness of the risks associated with deep mining is changing the face of the sector. This awareness, coupled with the unique challenges linked to deep mining, mean new projects are looking at smarter mining methods and at using innovative technology to assist in the mining process.
This drive for the newest technology is no exception in Zambia. The country is already showing promise to boast world-class machinery in its deep mines. Upon completion of Mufulira Deep, the headgear will be able to hoist 10 000 tonnes of copper ore to the surface every day, in a lift travelling at 18 metres per second. That’s six times faster than an average commercial office lift, and nearly twice as fast as the ultra-rapid passenger lift in the Burj Khalifa, the world’s tallest building, in Dubai.
Mines in the region are also spending time and resources on installing sophisticated air circulation and cooling systems in their mines, ensuring proper working conditions at even the deepest levels. The reason is simple: the deeper you go, the less oxygen there is and the warmer is gets. Ambient temperatures can reach 55C at 3km below the surface.
Institutions like the South African Centre for Scientific and Industrial Research (CSIR) are developing solutions to enhance mine safety. They have designed “Monster”, a robot that is able to assess and identify risks for underground mines, such as rock fall, without needing human beings to go into the mine.
“Mines are becoming more modern. Automation is taking many safety risks out of play,” Kotzé explains. That said, deep mining will never become people-free. With the increased use of technology and automated mining methods in Zambia’s deep mines, the need for specialist skills will increase. With new investments and expansions on Zambia’s deep mines, these specialist skills are being developed locally, setting Zambia up to reap the full potential of deep mining in the future.
See also: Underground at Konkola Deep