The Luele kimberlite mine (previously Luaxe), which Angola inaugurated in November, will, upon expansion of its plant, become the largest diamond mine in the country. The Luele resource is estimated to have 628 million carats and a lifetime of 60 years.
Catoca, which is set to be dethroned by Luale as the biggest mine in Angola, produces between 6 million and 7 million carats annually.
Paul Zimnisky, an independent diamond expert, estimated that Luele's initial output will be approximately 4 million carats, with the capacity potentially doubling in the future. He said Luele is the only large-scale diamond mine in the world, producing millions of carats annually, that is anticipated to begin operations this entire decade.
“Economic diamond deposits, especially ones as large as this, are exquisitely rare,” said Zimnisky.
“There are other large diamond deposits that have been discovered in places such as Siberia; however, for one reason or another, the mining economics are not robust enough to justify a mine-build investment, for example, because of the depth of the resource or other engineering challenges.”
Exploration
Because Luele is the only significant large-scale diamond mine that has been uncovered during the past decade, the difficulty of locating mines of this magnitude is avowed. Furthermore, the paucity of investors ready to support exploration is unfortunate.
Botswana Diamonds chairperson John Teeling informed investors in December that the lack of investor interest in the London AIM market had harmed all explorers.
“Mines have finite, often short lives, so it is highly likely that a future scarcity of many minerals, including diamonds, will occur,” he said.
“The surviving producers should benefit. Botswana Diamonds has a loyal but dwindling cohort of investors.”
Botswana Diamonds is conducting diamond exploration in Botswana, Zimbabwe, and South Africa.
This year, the company plans to initiate operations at the Thorny River project. The estimated ore content of the Thorny River ranges from 1.2 million to 2.1 million tonnes, with a grade of 46 to 76 carats per hundred tonnes.
This is considerably smaller than the Luele.
In the past 15 years, Lucapa Diamonds and its Angolan partners Endiama and Rosas & Petalas have been searching Lulo for primary kimberlite diamond deposits. Last year, a minimum of 560 geophysical anomalies were identified. From the 152 that were drilled, 132 were discovered to be kimberlite bodies. Two rough diamonds with a total weight of 15 carats were identified while evaluating the diamond potential of 14 kimberlite bodies.
Lucapa Diamonds and its associates are positive about the discovery of a substantial primary diamond deposit.
Additionally, Rio Tinto and De Beers are performing exploration operations in Angola. Rio Tinto returned to Angola in 2021 to investigate the Chiri kimberlite deposit in Lunda South. Rio Tinto has entered into a 35-year agreement with Endiama, whereby it will receive 25% of the project and 75% from the latter. Endiama is eligible for 49%.
After a decade-long absence, De Beers returned to Angola in 2022, where it entered into investment agreements with the government for 35 years of exploration and mining in two licenced regions in the northeast with Endiama.
In December 2019, a joint venture was formed between Alrosa and the Zimbabwe Consolidated Diamond Company (ZCDC) to investigate undiscovered diamond reserves within Zimbabwe.
Alrosa Zimbabwe, which is 70% controlled by the Russian corporation, was granted 40 exploration rights. The provinces of Manicaland, Masvingo, and North Matabeleland held the majority of the concessions.
In Sierra Leone, Newfield Resources is also constructing the Tongo mine.
Zimnisky remarked that despite the mine's annual output being in the hundreds of thousands of carats rather than millions, it is comprised of a series of kimberlite dykes containing diamonds of extraordinary quality.
Furthermore, he stated that the Beenchime/Khatystakh and Mayskaya projects in Russia could be sources of new supply.
Star Diamond and De Beers, respectively, possess the capacity to establish mines of moderate scale in the Canadian provinces of Nunavut and Saskatchewan.
Underground
An increasing number of mining corporations are allocating resources to migrate from open-cast mining operations to underground projects.
Following a $2.3 billion investment in 2012, underground production commenced at De Beers’ Venetia Mine in Limpopo, South Africa, last year. Venetia will have the capability of penetrating underground mine orebodies containing K01 and K02 orebodies to a maximum depth of 1,000 metres.
With an annual production average of 3.5 million carats from an estimated 4.5 million tonnes of material, K01, a substantial ore body spanning 550 by 120 metres, will serve as the primary source of output. An annual extraction of one million carats will occur from 1.5 million to 2.5 million tonnes of material contained within the K02 orebody, which spans an area of 200 meters by 300 metres.
"The investment in moving the world-class Venetia Mine underground increases De Beers Group's long-term global production and demonstrates our dedication to South Africa," said De Beers Managed Operations managing director Moses Madondo in July 2023.
"Our great team of employees and contracting partners have collaborated magnificently to reach this significant milestone of the first underground production. We anticipate this high-performing team to continue the good work as we ramp up production over the next few years, bringing significant advantages to our workforce, our host communities, and our commercial partners, as well as to South Africa as a whole."
Debswana, in which De Beers has a 50% stake, has just authorised a $1 billion investment for a critical phase of underground project development at Jwaneng, the company disclosed. This development will facilitate the transfer of the most precious diamond mine in the world from an open pit to an underground operation. De Beers said that preliminary operations will begin in May 2024, after the effective conclusion of feasibility investigations.
“Jwaneng stands proudly as the world’s greatest diamond mine. It is a central pillar of both the Botswana economy and the De Beers Group business,” said De Beers chief executive and Debswana deputy board chairperson Al Cook.
“The global supply of natural diamonds is falling, so moving forward with the Jwaneng Underground Project creates new value for investors, brings new technology to the country, creates new skills for our workforce, and provides new gems for customers around the world.”
Since it began operations in 1982, Jwaneng has generated an approximate yearly average of 11 million carats each year.
The Jwaneng underground project, according to De Beers, will safeguard the mine's long-term viability, generate employment opportunities in Botswana, and maintain Debswana's substantial economic contribution to the nation.
Additionally, in Botswana, in September 2021, Lucara Diamond approved the Karowe underground project (UGP), which is anticipated to prolong the mine's life. Preliminary underground carat production is anticipated to be primarily derived from the highest-value EM/PK(S) unit and, assuming conservative diamond prices, is projected to generate an additional $4 billion in revenue.
The feasibility study for the underground project was concluded in November 2019. Lucara said in July 2023 that the project was delayed by a year and a half, while the capital cost to complete it went up by $136 million. The underground project was allocated a pre-production capital cost of $514 million.
The UGP, which was once projected to be finalised in the latter part of 2026, will now not be finished until the initial six months of 2028.
These three underground initiatives serve as a conspicuous indication of the trajectory that miners will pursue in the absence of new substantive diamond deposits and when open-pit mining supplies run dry. It, however, remains a matter of time to establish if more underground mines will come onstream or if fresh diamond deposits like Luele will be opened shortly.
Mathew Nyaungwa, Editor in Chief of the African Bureau, Rough&Polished