Identifying the diamond potential of a kimberlite is both an academic and an economic challenge. Research into diamond formation could have “major implications for identifying areas where high-value type II diamonds are located,” says Richard Price, group mineral resource manager at Lucapa Diamond Company.
At the university level, a study published in November 2023 established a link between the presence of diamonds in a given kimberlite, and the ratio of magnesium to iron in the olivine the kimberlite contains. This provides a “new tool in diamond exploration,” says the study’s lead author, Dr. Andrea Giuliani, a senior scientist at ETH Zürich — though he’s quick to point out that it does not serve as conclusive proof. Fast, inexpensive analyses of olivine’s major elements are only indicators of diamond potential. “It must be included within exploration programs that employ other well-established geochemical methods,” he explains, adding that diamond is one of the hardest commodities to hunt.
Global diamond mining companies are following these academic studies closely to assess their practical applications. However, cost-benefit considerations remain. As Lucara Diamond Corp. CEO William Lamb notes, “the challenge with diamonds is [that] the probability of finding an economic kimberlite could cost $150 million in exploration, and you may come up empty-handed.”
Brownfield expansion
Access to capital and the uncertainty of exploration mean many miners, Lucara included, are focusing on brownfield expansion — working with sites that have already been mined, as opposed to new ones. Lucara’s Karowe underground expansion project in Botswana is expected to extend the mine’s life until at least 2040 and generate approximately $4 billion in additional revenue. The project ensures access to the highest-value portion of the Karowe ore body, where the company has recovered many large, high-value diamonds, including the 1,109-carat Lesedi La Rona.
Lucapa, meanwhile, is considering vertical-pit mining (VPM) for its smaller deposits, notably the Merlin diamond project southeast of Darwin in Australia’s Northern Territory. “The narrow, conical shape of the deposits means that using VPM instead of open-pit mining from a certain depth is more economical, as you don’t have to strip out so much waste rock,” explains Price.
Others are looking beyond dry land. Since 2018, Burgundy Diamond Mines has been developing an underwater remote mining (URM) system, in conjunction with maritime technology specialist IHC Mining, to extend the life of Burgundy’s Ekati deposit in Canada’s Northwest Territories. Consisting of an underwater mining crawler, a launch and recovery (LARS) platform, and a shore-based dewatering plant, the URM system is “intended to economically extract kimberlite from sub-economic kimberlite pipes and from deep extents of completed open pits,” says Burgundy CEO and managing director Kim Truter.
The crawler, which the company expects to receive at Ekati in 2025, will excavate kimberlite ore in small layers at depths of up to 500 meters, eliminating the need for removing surrounding rock or using explosives. “The URM crawler will be equipped with the latest underwater control, imaging and positioning equipment to ensure we target only the economic kimberlite ore to minimize environmental impact and maximize successful extraction,” says Truter.
Successful sorting
In conjunction with its URM project, Burgundy is using X-ray transmission (XRT) sorting to identify and collect large stones more effectively. Lucara was one of the earliest adopters of this technology, which it uses at the Karowe mine to ensure that large type IIa diamonds emerge intact.
“XRT machines detect carbon particles, such as diamonds, and separate these materials from waste rock,” Lamb explains. And the results speak for themselves: Lucara recovered the Lesedi La Rona within weeks of the first installation. In August 2023, it unearthed its fourth diamond of 1,000 carats or more. This focus on processing efficiencies and maximizing mine output is also evident in Lucara’s autogenous milling technology, which allows for high volume and quicker processing by combining multiple stages of crushing, screening and grinding into one.
Artificial intelligence
Although brownfield expansion is in focus, the potential use of artificial intelligence (AI) in diamond exploration is an exciting new frontier. At Ekati, machine-learning AI “draws on multiple datasets supplemented with human input to target the most beneficial exploration targets on site, including a new kimberlite, which was previously unidentified,” says Truter.
Similarly, this past April, Botswana Diamonds announced plans to apply AI to its database, which includes data on 95,000 square kilometers of land, 228,000 soil sample results, and airborne geophysical surveys covering 375,000 kilometers.
“Our mineral database in Botswana is simply vast, too big for timely analysis by humans,” explains executive chairman John Teeling.
“It is early stages in both our work and the use of the technique in mineral exploration, but the future potential is huge.”
Image: Underground diamond mining at the Ekati deposit. (Burgundy Diamond Mines)
This article is from RDI Diamond’s Welcome to the Future special report. View other articles from the supplement here.
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