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Karowe mine

17th October 2014

  

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Name: Karowe mine.

Location: The Karowe mining licence is located in north-central Botswana, 25 km south of the Orapa diamond mine and 23 km west of the Letlhakane diamond mine.

Controlling Company: Lucara Diamond Corp, through its 100%-owned subsidiary Boteti Mining.
Brief History: De Beers discovered the AK6 kimberlite in 1969; however, the project was not pursued until 2000, when further drilling and geophysical surveys indicated that the pipe was larger than previously estimated. De Beers released the project to a joint venture (JV) in April 2004.

Detailed exploration from 2004 to 2006 resulted in applying for a mining permit in September 2007, with the mining licence granted in October 2008. Boteti Exploration was a JV between De Beers, African Diamonds and Wati Ventures.

Following the completion of a feasibility study in October 2008, De Beers sold its interest in the project to an indirect wholly owned subsidiary of Lucara Diamond Corp. In the interim, Boteti commissioned the feasibility study, which was subsequently completed and accepted by the Boteti board of directors in June 2010. In November 2010, a formal decision was taken to proceed with the construction of the mine. Later that year, Lucara secured a 100% interest in the AK6 project.

In December 2011, the AK6 project was renamed the Karowe mine. Construction of the mine was substantively completed by the end of March 2012 and the first production diamonds were recovered in April. Full commercial production at the Karowe mine was declared on July 1, 2012 and, by August 2012, the mine had ramped up to full production.

Brief Description: The Karowe mine is an openpit diamond mine with associated key components, including mining infra- structure, an access road, power supply and water supply.

Geology/Mineralisation: The Karowe mine is based on the AK6 kimberlite pipe, which is part of the Orapa kimberlite field.

AK6 is a north-south elongate kimberlite body with a near- surface expression of about 3.3 ha and a maximum area of about 7 ha at an estimated 120 m below surface. The body comprises three geologically distinct, coalescing pipes that taper at depth into discrete roots. These pipes are referred to as the North, Centre and South lobes.

The AK6 kimberlite is an opaque mineral-rich monticellite kimberlite, texturally classified primarily as fragmental volcanic- lastic kimberlite, with lesser macrocrystic hypabyssal facies kimberlite of the Group 1 variety.

Reserves: Total probable mineral reserves as at December 26, 2013, were estimated at 33.13-million tonnes grading 15.5 carats per hundred tonnes.

Resources: Total indicated mineral resources as at October 21, 2013, were estimated at 48.07-million tonnes, containing about 7.61-million carats. Inferred mineral resources were estimated at 21-million tonnes, containing about 3.04-million carats.

Products: Diamonds.

Mining Method: Openpit.

Major Infrastructure and Equipment: The current flow sheet consists of primary crushed run-of-mine ore being processed through a single autogenous grinding mill, with the +35 mm mill product crushed in a single pebble crusher and then recirculated to the mill. The +1.5, –35 mm mill product is processed through a dense-media separator (DMS), with the DMS sinks reporting to an X-ray recovery circuit comprising a single-pass coarse X-ray circuit and double-pass fines and middles X-ray circuits. The –1.5 mm material is pumped to a degrit circuit, where the grits report with the DMS tailings to the tailings dump. The slimes are pumped to a thickener and then to a tailings storage facility.

The increase in the orebody hardness has required several modifications to the comminution circuit so that the process plant can maintain a throughput of 350 t/h. The comminution circuit upgrade comprises a new secondary gyratory crusher, a bleed circuit ahead of the autogenous grinding mill, new auto- genous grinding-mill discharge grates, the installation of turbo pulp lifters in the autogenous grinding mill and the inclusion of a bleed screen after the pebble crusher.

The mining fleet is owned and operated by Kalcon.

Prospects: Karowe’s plant optimisation project to modify the process plant to treat the harder material at depth and improve the recovery of exceptional diamonds is advancing. Orders have been completed for long-lead items, and the project is scheduled for completion by early 2015.

Contact Person: Investor relations, Sophia Shane.

Contact Details:
Lucara Diamonds,
tel +1 604 689 7842,
fax +1 604 689 4250,
email sophias@namdo.com, and
website http://lucaradiamond.com.

Edited by Samantha Herbst
Creamer Media Deputy Editor

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