Name of the Project
Karowe underground diamond mine.

Location
Botswana.

Client
Lucara Diamonds.

Project Description
The results of a preliminary economic assessment have demonstrated the potential economic viability for the development of an underground mine at Karowe once the openpit mine is completed.

The Karowe underground project targets the South Lobe kimberlite resource below the current planned bottom of the openpit.

The Karowe mine AK06 mineral resource comprises 42.23-million tonnes grading 13.88 ct per hundred tonnes (cpht) in the indicated category and 20.57-million tonnes in the inferred category grading 14.48 cpht.

The bulk underground mining method selected to mine the AK06 kimberlite resource, measuring about 200 m in diameter, is sublevel caving (SLC). Initially, the pipe will be partially offset from the pit bottom, resulting in the top four sublevels being slightly offset from the pit bottom. 

Owing to its lower initial capital cost, SLC was considered. These top levels and two levels below the pit bottom will be mined by a derivation of sublevel openstoping daylighting into the pit bottom.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has a base case post-tax net present value, at a 5% discount rate, of $451-million and an internal rate of return of 38.9%, with a pretax payback of 2.5 years.

Value
Preproduction capital costs, including a 25% contingency, the costs of prefeasibility and feasibility studies, as well as hydrogeology and geotechnical testing and modelling costs, have been estimated at $195-million.

Duration
Not stated.

Latest Developments
Lucara expects to complete a National Instrument 43-101-compliant prefeasibility study by the second quarter of 2018.

Key Contracts and Suppliers
None stated.

On Budget and on Time?
Not stated.

Contact Details for Project Information
Lucara Diamonds, tel +1 604 689 7842, fax +1 604 689 4250 or email info@lucaradiamond.com.