1. Mutanda, DRC
Glencore’s (LON: GLEN) Mutanda copper-cobalt mine in the Democratic Republic of the Congo (DRC) topped the list, weighing in with proven and probable reserves of 245 million tonnes of 1.52% copper and 0.6% cobalt, for a total of 3.7 million tonnes copper and 1.5 million tonnes cobalt.
The mine, which has operated since 2007, produces 200,000 tonnes copper and 24,000 tonnes cobalt a year.
Glencore bought the other 31% interest in the operation from the private investing firm Fleurette Group in February for US$922 million.
Mutanda is in the DRC portion of the central African copper belt, an arcuate-trending package of rocks known to contain some of the world’s largest sedimentary-hosted copper deposits. The deposits formed in the early Proterozoic, when metal-rich, oxidizing brines migrated and reacted with horizons in the region’s stratigraphy.
2. Tenke Fungurume, DRC
China Molybdenum and BHR Partners’ Tenke Fungurume copper-cobalt mine in the DRC ranks as the second-largest cobalt reserve in the world. The deposit contains 144.4 million proven and probable tonnes of 2.36% copper and 0.36% cobalt, for a total of 3.4 million tonnes copper and 521,260 tonnes cobalt.
The operation, 40 km east of Glencore’s Mutanda copper-cobalt mine, produced 215,940 tonnes copper and 16,050 tonnes cobalt in 2016.
International miners Freeport-McMoRan (NYSE: FCX) and Lundin Mining (TSX: LUN) recently sold their stakes in Tenke to Chinese firms. China Molybdenum bought a 56% stake in the operation from Freeport for US$2.65 billion last November, while Lundin sold its 24% interest to BHR Partners for US$1.14 billion in April. A Congolese state mining company owns the other 20% interest.
3. Mashamba East, DRC
Katanga Mining’s (TSX: KAT) open-pit Mashamba East copper-cobalt mine, 80 km west of Tenke Fungurume, stands as the world’s third-largest cobalt reserve, with 32.1 million proven and probable tonnes of 2.13% copper and 0.6% cobalt, for 683,730 tonnes copper and 192,600 tonnes cobalt.
The historic mine produced 9.8 million tonnes ore at 4.96% copper and 0.35% cobalt over its 13-year mine life, before closing in 1988 due to lack of funds.
Mashamba East is a satellite deposit to Katanga’s larger Kamoto copper-cobalt operation, which it owns with its 25% joint-venture partner, the Congolese state mining company.
Under the joint venture, Kamoto began commercial production in 2008 but stopped in 2015 so the company could build a processing plant while metal prices were low. The US$880-million upgrade included commissioning a new leach plant, which will replace the oxide concentration process.
Katanga intends to restart the operation this September, and has already begun waste stripping at Mashamba East and another oxide open-pit resource called the KOV. Production is pegged at 300,000 tonnes copper and 22,000 tonnes cobalt a year.
In February, Glencore raised its interest in Katanga from 75% to 86% for US$38 million.
4. Murrin Murrin, Western Australia
Glencore’s Minara Resources is one of Australia’s top nickel and cobalt producers. The company’s Murrin Murrin nickel-cobalt mine in the northeastern goldfields of Western Australia produced 35,300 tonnes nickel and 2,800 tonnes cobalt last year.
Murrin Murrin is a laterite nickel deposit, which forms when nickel and cobalt collect in clays due to extensive weathering of olivine-rich ultramafic rocks at surface.
The open-pit mine hosts the fourth-largest cobalt reserve on the planet, with 237.9 million proven and probable tonnes of 0.94% nickel and 0.06% cobalt, for a total 2.2 million tonnes nickel and 142,740 tonnes cobalt.
5. Ambatovy, Madagascar
The Ambatovy laterite nickel-cobalt mine — 80 km east of Madagascar’s capital Antananarivo — is the fifth-largest cobalt reserve, with 186 million proven and probable tonnes of 0.85% nickel and 0.07% cobalt for 1.6 million tonnes nickel and 137,600 tonnes cobalt.
The open-pit operation is jointly owned by Toronto-based Sherritt International (TSX: S), which holds 40%. Sumitomo has 30% and Korea Resources has 27.5%. The US$5.3-billion mine reached commercial production in 2014, and produced 75,033 tonnes nickel and 6,967 tonnes cobalt in 2016.
In May, Sherritt struck a deal with its Korean partners to lower its stake in Ambatovy from 40% to 12%, in a bid to eliminate US$1.4 billion in debt.