VANCOUVER, BC — January 5, 2026 — Leads & Copy — Lucara Diamond Corp. has announced the results of an updated technical report for the updated Feasibility Study on its Underground Project at the Karowe Diamond Mine in Botswana.
The report, titled “Karowe Mine – Botswana 2025 Feasibility Study Technical Report,” has an effective date of September 30, 2025, and was prepared for Lucara by JDS Energy & Mining Inc. It will be available under the Company’s profile on SEDAR+ and from the Company’s website within 45 days of this news release.
Karowe is located in north-central Botswana, a diamond producing area, and is a producer of large, high value Type IIa diamonds. The UGP at Karowe is expected to extend the mine life and generate revenue and cashflow to 2038, benefitting the Company, its employees, shareholders, communities surrounding the mine, and Botswana. The Report provides an update to the 2023 FS and 2021 financed base case to reflect changes to capital expenditure, project schedule, and applied mining technical solutions for the Project.
The underground mine life is projected to be 10 years, with total Life of Mine diamond recoveries of 4.5 million carats. Operational highlights include approximately 28.5 million tonnes of ore to be mined and approximately 37.3 million tonnes of ore to be processed.
The highest value EM/PK(S)1 unit of the South Lobe is the dominant rock type to be mined over the LOM of the UGP. This area has historically produced large high-value diamonds, including the 2,488 carat Motswedi diamond, the 1,109 carat Lesedi La Rona, the 549 carat Sethunya, and the 2,035 carat and 1,019 carat diamonds recovered in July and August 2025, respectively.
Pre-production capital costs for the UGP until production starts in H1 2028 are estimated at $779 million, with more than $436 million already spent on the Project over five and a half years. Karowe is expected to generate more than $1.3 billion in net income, and the after-tax unlevered NPV8% is $432.1 million, excluding the impact of interest deductibility on tax and costs incurred to date.
The updated report incorporates project construction progress to September 30, 2025, a revised economic model with updated exchange rates and diamond prices, re-baselining of the UGP schedule, re-estimation of current operations budgets and project capital and operating cost projections, geological model updates, hydrogeological and geomechanical model updates, mine design updates, advancement of detailed engineering designs, and groundwater management on the surface.
The UGP is focused on the highest value domain of the South Lobe of the AK6 kimberlite, designed to support the operation of a 2.85 million tonnes per annum underground mine and processing plant. An 8.5 metre diameter production shaft and a 6.0 metre diameter ventilation shaft have been successfully sunk to final depths.
Bulk mining will be conducted by Long Hole Shrinkage drill and blast mining methods from 310 metres above sea level to 490 masl. Run of Mine material will be transferred to an underground jaw crusher and conveyor system, then to the surface via conveyors and rehandling equipment.
The Company anticipates that the remaining pre-production capital costs of $343.2 million will be funded through a combination of operating cash flow, as well as new equity/debt financing.
Key operational projections include 28.5 million tonnes of underground ore to be mined, 37.3 million tonnes processed, diamond reserve grade of 12.2 cpht, 4.5 million carats recovered, and diamond revenue of $3,365 million over a mine life of approximately 10 years.
William Lamb, President and CEO of Lucara, said the updated Feasibility Study reinforces the strategic decision to extend mine life and continue to generate benefits for stakeholders. Lamb added that Karowe is a world-class mine, and the company looks forward to recovering large, exceptional diamonds from the underground project.
Mine operating costs are estimated based on actual cost data, reference projects, and budgetary quotes. The capital cost estimate was prepared using a combination of first principles, benchmarking, and vendor/contractor quotes.
The main economic assumptions include a BWP:US$ FX rate of 14.0 and a ZAR:US$ FX rate of 17.5. Baseline diamond prices are $695/ct for EM/PK(S), $520/ct for M/PK(S), and $304/ct for LOM & Mixed Stockpiles.
A sensitivity analysis shows that the Project is most sensitive to diamond prices and least sensitive to capital costs.
The 2025 Mineral Resource Estimate for Karowe utilizes back-captured and recompiled daily open pit production data. The 2025 mineral resources for Karowe have been classified as either Indicated or Inferred Mineral Resources, according to CIM Definition Standards for Mineral Resources and Mineral Reserves (CIM, 2014).
All Mineral Reserves are classified as Probable Mineral Reserves. The QP has not identified any legal, political, or environmental risks that would materially affect potential Mineral Reserves development.
Extensive geotechnical field programs and studies (2018-2025) have been conducted, with both empirical and state-of-the-art numerical modelling applied to assess the cavability of the kimberlite pipe. Detailed hydrogeological models have been prepared to reflect site conditions, taking into account observed groundwater inflows recorded from the two mine shafts. Preliminary and confirmatory XRT testing demonstrated that the Tertiary XRT sorter can accurately distinguish liberated diamonds from main host rocks at the Karowe underground deposit.
The open pit at Karowe is expected to terminate in H1 2026. The modified hybrid mining method described in the 2025 FS provides several technical and operational advantages over the 2023 FS.
The UGP at Karowe will utilize a combination of existing and newly constructed infrastructure at the Karowe 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.
Karowe completed its latest Environmental Impact Assessment/Environmental Management Plan in 2020 and received approval from the Botswana Department of Environmental Affairs during the same year. The mining license was renewed in 2021 for a period of 25 years and expires on January 3, 2046.
The QPs conclude that the 2025 FS summarized in this news release contains adequate data and information to support a FS.
On December 30, 2025, the Company reached an agreement with the lenders under its Project and Working Capital facilities to waive all events of default. Under the agreement, certain deadlines have been extended.
For further information, contact:
William Lamb
President and Chief Executive Officer
Source: Lucara Diamond Corp.
