JOHANNESBURG—With few new gold strikes around the world that can be turned into profitable mines, South Africa’s gold miners are planning to dig deeper than ever before to get access to rich veins.
The plans raise questions about how to safely and profitably mine several miles below the surface. Success would mean overcoming problems such as possible rock falls, flooding and ventilation challenges and designing technology to overcome the threats. Deep mining isn’t easy, nor pleasant. The deeper a mine goes, the more at risk it is from underground earthquakes, rock bursts, gas discharges and flooding. And for workers, conditions themselves get progressively more uncomfortable from heat and cramped spaces.
Mark Cutifani, chief executive officer of AngloGold Ashanti Ltd., has a picture in his office of himself at one of the deepest points in Africa, roughly 4,000 meters, or 13,200 feet, down in the company’s Mponeng mine south of Johannesburg. Mr. Cutifani sees no reason why Mponeng, already the deepest mining complex in the world, shouldn’t in time operate an additional 3,000-plus feet deeper. Not every gold mine can operate at 16,500 feet below the surface, as AngloGold wants to do, but Mr. Cutifani has pulled together a team from about 30 companies, including General Electric Co. and 3M Co., to research technology to allow workers at Mponeng to mine that deep.
South Africa is at the forefront of deep mining. Agnico-Eagle Mines Ltd.’s LaRonde mine in northwestern Quebec, one of the deepest mines outside South Africa, operates at about 7,260 feet below the surface. Before closing in 2002, Homestake Gold Mine in South Dakota was considered the deepest mine in the Western Hemisphere at about 8,045 feet. Nowhere else do mines go so deep as in South Africa, and lessons learned there from attempts to extend the life spans of mines will be applicable globally, not just for gold but for extracting other minerals underground.
South Africa, once the leader, began to slip in the global gold-production rankings in 2006 and continues to do so, as mining companies have used up higher-grade reserves in their mines. The country fell a further notch in 2009, this time to fourth behind China, the U.S. and Australia. Local executives expect the trend to continue.
The country’s two biggest gold companies, AngloGold and Gold Fields Ltd., have plans to fight back and expect to maintain output levels in the years ahead—by digging downward and outward.
For AngloGold and Gold Fields, the world’s third- and fourth-largest producers of the metal, this has meant bidding for assets in other parts of Africa, South America and elsewhere when opportunities arise. And in their home country, it means looking for ways to access gold they are sitting on.
Abstract from The Wall Street Journal, dated February 18, 2011, article by Robb M Stewart, http://online.wsj.com