Lucara Diamond Corp. announced the filing of a technical report for the updated Feasibility Study prepared in accordance with National Instrument 43- 101 - Standards of Disclosure for Mineral Projects ("NI 43-101") on its Underground Expansion Project ("UGP" or "Project") at the Karowe Diamond Mine ("Karowe") located in Botswana. The Report is titled "Karowe Mine - Botswana 2023 Feasibility Study Technical Report", with an effective date of June 30, 2023, and was prepared for Lucara by JDS Energy & Mining Inc. Karowe is located in north-central Botswana, one of the world's most prolific diamond producing areas, and is a producer of large, high value type IIa diamonds and the only diamond mine to have produced four diamonds in excess of 1,000 carats in size.

The underground expansion at Karowe is expected to double the mine life, and to generate significant revenue and cashflow out to 2040, extending benefits to the Company, its employees, shareholders, communities surrounding the mine, and Botswana. The Report provides an update to the 2019 underground feasibility study ("2019 FS") and 2021 financed base case to reflect changes to project duration, capital expenditure, and technical updates to the Project. All amounts are in U.S. dollars unless otherwise noted.

Combined Open Pit/Underground Highlights: Extending mine life by 15 years; Total life of mine (LOM) diamond recoveries of 6.8 million carats; Operational highlights include ~42.4 million tonnes of ore mined and ~52.2 million tonnes of ore processed; Highest value EM/PK(S) unit of the South Lobe is the dominant rock type mined over the LOM of the underground; a significant source of many large high value diamonds, including the 1,109 carat Lesedi La Rona, the 549 carat Sethunya, and more recently the 1,080 carat Type IIa white stone recovered in August 2023; Pre-production capital costs for the UGP totalling $683 million, to be expended over an eight-year pre-production construction and commissioning period until H2/2027, of which three and a years have already been successfully completed; The UGP is projected to generate $1.1 billion in cash flow; Fully financed project as announced on January 9, 2024 (link to Press Release), when the Company amended its debt package that was originally entered into in 2021; and 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 (the WCF) which is used to support ongoing operations along with operating cash flow from the Karowe open pit. Project Description: The UGP is focused on the South Lobe of the AK06 kimberlite; The UGP is designed to support operation of a 2.7 million tonnes per annum underground mine and processing plant; 8.5 metre finished internal diameter Production Shaft approximately 767 metres deep equipped to hoist a nominal 7,400 tonnes per day of ore and additional development waste; 6 metre finished internal diameter unequipped Ventilation Shaft with a planned final depth of 729 metres; Extraction of approximately 400 vertical metres of the South Lobe of the AK06 kimberlite from 310 metres above sea level ("masl") (700 metres below surface) to the bottom of the depleted open pit (approximately 710 masl or 300 metres below surface). Feasibility Study Approach: The FS has been prepared following Canadian Institute of Mining Guidelines for the development of an underground mine.

Production from the underground is planned after open pit operations have been completed and the Company will rely on the processing of stockpiled material during the latter part of the underground development and ramp- up to full production in first quarter, 2028. The results of the FS represent forward-looking information that are subject to a number of risks, uncertainties and other factors that may cause results to differ materially from those presented here. Mineral Resources: The 2023 mineral resource estimate for Karowe incorporates drilling and sampling data obtained prior to 2018, and additional drilling and sampling information obtained in 2018/2019 which targeted delineation of the deep extension of South Lobe (deeper than approximately 600m from surface).

In 2019, the geological data were used to develop an updated internal geology model for the South Lobe and to update the external contacts for the South, Centre and North Lobes. The 2023 update also includes geological information and production data derived from open pit mining to the end of June 30, 2023.