Toronto-listed Lucara Diamond, along with its partner in the project, mining and mineral processing project services provider United Mining Services (UMS), on September 4 hosted a final production shaft blast ceremony and safety milestone celebration for Lucara’s Karowe diamond mine, in Botswana, as it readies for the next stage of mine development.

The last blast for the 770-m-deep production shaft took place in late July, and the event was held to celebrate this milestone, as is common practice in the industry owing to the unpredictable and risky nature of shaft sinking, Lucara president and CEO William Lamb explained.

He highlighted that this was achieved with a ”remarkable” 2 000 lost time injury- (LTI-) free days, since work began four years ago, and nearly 5.72-million LTI-free hours.

Lamb acclaimed that, simultaneously, the company was able to achieve sinking through difficult conditions including two aquifers, sandstone and mud stones to reach the bottom of the shaft.

“The 2 000 hours that you see – start as you mean to finish. . . . Two thousand hours is how we’ve started. This is how we have to carry on. It is not just an achievement, it is now the foundation on which we will drive the rest of the project,” he emphasised.

The safety performance was attributed to an emphasis on implementing a safety culture that included all stakeholders, as well as myriad of initiatives, campaigns, supervisions and systems being implemented, UMS CEO Digby Glover said.

This included, but was not limited to, an 11-member unit to respond to any underground incidents, investment in the identification of hazards and the implementation of mitigation and control measures and testing these.

UMS’s mine hoists and lashing gear have modern and advanced control and safety systems, UMS technical director Murray Macnab highlighted.

The company also invested in a large crew of hoist experts to ensure consistent quality and knowledge-retention on hoist-specific shaft sinking programmable logic controller safety systems, designed in-house by the company.

UMS also provided a ‘mock-up’ on-site training unit to undertake initial and refresher training of operators.

Karowe’s current openpit reserve is expected to be fully depleted by year-end and the underground project (UGP) is designed to extend the life of the mine and access the highest-value portion of the orebody.

Access to the underground mine will be from the 770-m-deep production shaft, which is 8.5 m in diameter. A second shaft will serve as the main exhaust route and secondary egress for the mine.

UMS’s involvement in the project entailed the twin shaft sinking, equipping and infrastructure work for the mine. It had been involved in the project since the final stages of the feasibility stage, in 2019, with the initial role of reviewing the shaft component, preparing designs for early works and initiating long-lead procurement, Glover explained.  

He highlighted that completion of shaft sinking was delivered ahead of contractual schedule, and notably, without a single LTI, as alluded to.

First blast for the production shaft occurred on September 27, 2021, and the last on July 28 this year at 770.29 m.

“This shaft is not only vital to the future of the Karowe mine – it holds significance for many stakeholders. It has created employment for people from Letlhakane and across Botswana, but it has also fostered high-performing teams with rare and valuable shaft sinking skills.

“These skills can serve ongoing operations or can contribute to the broader growth of Botswana’s mining economy by being deployed on future underground projects,” Glover acclaimed.

Achieving this means that the next stage of development can proceed, that is, shaft equipping, Glover informed, noting that this was already under way with steelwork to arrive soon.

A lengthy process, he said that milestones being targeted in this process included commissioning and licensing the conveyances to allow for people to be transported legally down the shaft; as well as commissioning the materials handling system to allow for underground material to start being brought to surface.

An operational-readiness programme is also underway for when the mine is operational, with this slated to be brought online in the first quarter of 2028.