Lucara Diamond Corp. has filed a technical report for the updated feasibility study on its underground expansion project at the Karowe Diamond Mine in Botswana, prepared by JDS Energy and Mining Inc.

The study, prepared in accordance with National Instrument 43-101—Standards of Disclosure for Mineral Projects (NI 43-101), offers comprehensive insights into the anticipated outcomes of the underground expansion initiative.

Karowe Diamond Mine, located in north-central Botswana, is renowned for its production of large, high-value type IIa diamonds. It holds the distinction of being the only diamond mine globally to have yielded four diamonds exceeding 1,000 carats in size.

The underground expansion is expected to double mine life and generate significant revenue and cash flow until 2040, benefiting the company, employees, shareholders, surrounding communities, and Botswana. The 2019 feasibility study and 2021 financed base case have been updated, reflecting changes in project duration, capital expenditure, and technical updates.

William Lamb, President and CEO of Lucara Diamond, commented:

“Lucara is excited to share the updated feasibility study for the Karowe Underground Expansion Project, which reinforces our strategic decision to extend mine life and continue to generate benefits for our stakeholders. Karowe is a world-class mine, and we look forward to continuing to recover large, exceptional diamonds from the South Lobe at Karowe.”

This report is updated from the original  2019 UGP FS and  2021  financed base case and highlights significant modifications such as project construction progress to June 30, 2023, revised economic modelling with updated diamond prices and exchange rates, re-baselining the UGP schedule, re-estimating operations budgets and project capital and operating cost projections, modifying mine design, fine tailings storage and management, and re-modeling hydrogeological conditions.

The report also includes changes to underground dewatering and grouting methodology and groundwater management on the surface.

Underground highlights

• The mine has been extended by 15 years, with 6.8 million carat diamond recoveries and approximately 42.4 million tonnes of ore mined and processed.
• The South Lobe’s highest-value EM/PK(S) unit is the primary underground rock type, a significant source of high-value diamonds like Lesedi La Rona, Sethunya, and Type IIa white stone, recovered in August 2023.
• Pre-production capital costs for the UGP total $683 million, to be expended over an eight-year pre-production construction and commissioning period until H2/2027, of which three and a half years have already been successfully completed.
• The UGP, a fully financed project, is expected to generate $1.1 billion in cash flow, as announced on January 9, 2024, following an amendment to its debt package.
• The amended facilities consist of a project finance facility (“project loan”) of $190.0 million (previously $170.0 million) to fund underground development and a $30.0 million (previously $50.0 million) senior secured working capital facility (“WCF”), which is used to support ongoing operations along with operating cash flow from the Karowe open pit.