Name of the Project
Karowe diamond mine underground project (UGP).

Location
Karowe diamond mine, north-central Botswana.

Project Owner/s
Canadian diamond mining company Lucara Diamond Corp.

Project Description
Lucara is developing a UGP at Karowe to extend the mine’s life and continue the production of large, high-value Type IIa diamonds. The UGP is focused on the highest-value domain of the South Lobe of the AK6 kimberlite, which remains open at depth. The project has a diamond reserve grade of 12.2 carats per hundred tonnes.

The project is designed to support a 2.85-million-tonne-a-year underground mine and processing plant to recover an estimated 4.5-million carats of diamonds over the UGP’s ten-year mine life. 

Mining will use a hybrid method, comprising longhole shrinkage drill-and-blast bulk mining, transitioning to block/free caving at higher elevations where unassisted caving is expected. 

The underground mine will use a combination of existing and newly built infrastructure at the mine. All current and planned surface installations have been designed to fully support the long-term operation of the underground mine and the processing plant.

Run-of-mine material will be handled by an underground jaw crusher and conveyor system to shaft skips, with surface conveying and rehandling to the plant and waste facilities.

The openpit is expected to terminate in the first half of 2026. Surface stockpiled reserves will be processed as required while the underground mining operations ramp up to commercial production.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has an after-tax unlevered net present value, at an 8% discount rate, of $432.1-million.

Capital Expenditure
Preproduction capital costs to production are estimated at $779-million (over an eight-year preproduction construction and commissioning period), of which more than $436-million has been spent to date. The remaining preproduction capital costs of $343.2-million will be funded through a combination of operating cash flow, as well as new equity/debt financing. 

Planned Start/End Date
Production is planned to start in the first half of 2028, with full-scale output thereafter.

Latest Developments
Lucara has reported that 2025 was a key delivery year for the Karowe UGP, but that additional funding will be needed to complete the underground expansion.

The project reached a major construction milestone during 2025, with the production shaft (776 m) and ventilation shaft (729 m) sunk to final depth. Lateral development advanced on multiple levels and the project exceeded 2 000 lost-time injury-free days.

Operationally, the project mined about 1.9-million tonnes of ore and processed about 2.8-million tonnes in 2025, broadly consistent with 2024, while unit processing costs decreased to $27.15/t. In the fourth quarter, it processed 705 513 t at an average grade of 12.2 ct/100 t, producing 86 110 ct from direct ore feed.

Lucara has further indicated the continued recovery of large stones at Karowe in 2025, including 772 “specials” (diamonds larger than 10.8 ct), 31 stones larger than 100 ct, and three stones of more than 1 000 ct (among them a 2 036 ct near-gem diamond and a 37.42 ct pink Type IIa stone).

For the UGP, Lucara has reported 2025 capital expenditure of C$75.8-million (including C$20.3-million in the fourth quarter), focused on shaft sinking and developing the 245 m, 285 m, 310 m and 335 m levels to connect the shafts and start lateral development. A lateral development contract was awarded in December to Group R Mining and Exploration Botswana to advance underground infrastructure towards the kimberlite orebody.

Key Contracts, Suppliers and Consultants
JDS Energy & Mining Inc and leading independent consultants (updated feasibility study). Matthew Moss (P.Eng) (project manager and independent qualified person; and Lucara’s VP mineral resources and qualified person Dr Lauren Freeman.

Contact Details for Project Information
Lucara Diamond Corp. Tel: +1 604 674 0272. Email: info@lucaradiamond.com.