Name of the Project
Karowe underground project.

Location
Botswana.

Project Owner/s
Lucara Diamond Corp.

Project Description
The Karowe mine is an existing conventional drill-and-blast openpit operation, with diesel excavators and trucks providing an average of 2.6-million tonnes a year of kimberlite feed for the mill. The openpit mine operation is expected to terminate in mid-2026, ending at an elevation of about 700 m above sea level.

The project is expected to extend the mine life to at least 2040, with underground carat production coming predominately from the highest-value EM/PK(S) unit.

Longhole shrinkage underground bulk mining has been selected to provide early access to higher-value ore and allow for a short payback period.

The underground project is designed to access the South Lobe kimberlite resource below the current planned bottom of the openpit, which is expected to be at about 700 m above sea level, to a depth of 310 m above sea level.
 
Access to the South Lobe underground will be through two vertical shafts.

A 767-m-deep production shaft, 8.5 m in diameter, driven from surface, will be equipped with two 21 t skips for production hoisting and a service cage for man-and-material movement through the mine. This shaft will also serve as the main fresh-air intake to the mine.

A second shaft, 6 m in diameter, driven 733 m deep from surface, will form the main ventilation exhaust pathway.

All underground mined kimberlite will be processed at the existing Karowe processing plant over a 13- to 15-year period following the cessation of the current openpit operations, which is expected to occur in 2026.

Life-of-mine production (remaining openpit and underground) is estimated at 7.4-million carats.

The underground expansion is expected to extend Karowe’s mine life by 13 years.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has an after-tax net present value, at a 5% discount rate, of $750-million, with a payback of about three years, for the combined openpit and underground mine.

Capital Expenditure
Lucara has updated the estimated capital cost, reporting an increase from $534-million to $547-million to reflect expected pricing changes following the execution of the main sink contract. The underground expansion is expected to extend Karowe’s mine life by 13 years.

Planned Start/End Date
The company will complete shaft sinking in 2024 and the ramp-up is scheduled for the first quarter of 2026, with full production from the underground mine expected in the second half of that year.

Latest Developments
Lucara has started sinking the main shaft at its Karowe diamond mine expansion project, although the transition from presinking has taken longer than planned.

The miner has also stated that it has identified opportunities to decrease the main sink cycle times, which should limit the impact on the project’s schedule.

“Momentum on the underground expansion continues to ramp up as we began the transition towards the main shaft sinking phase; Lucara maintains access to ample liquidity to support its growth plans,” CEO Eira Thomas has said.

During the second quarter, $29.2-million has been invested in the Karowe underground project, which is focused on the transition to the main sink activities and the construction of the upgraded transmission line and related substations.

Key Contracts, Suppliers and Consultants
UMS Botswana (presink construction contract); UMS South Africa (shaft sinking equipment procurement); UMS subsidiary METS International (shaft engineering contract); and JDS Energy & Mining (engineering, procurement and construction management) for the execution of the Karowe underground project.  

Contact Details for Project Information
Lucara Diamond Corp investor and public relations, tel +1 604 674 0272 or email info@lucaradiamond.com.