September 18, 2012

High Diamond Grade and Large Diamonds from Bulk Sampling of the Katcha Dyke in Guinea

18 September 2012

AIM: STEL

Stellar Diamonds plc

(“Stellar” or the “Company”)

High Diamond Grade and Large Diamonds from Bulk Sampling of the Katcha Dyke in Guinea

Stellar Diamonds plc, the London listed (AIM: STEL) diamond development company focused on West Africa, is pleased to announce final bulk sampling results from the Katcha Dyke at the Company’s Droujba kimberlite project in Guinea.

Highlights:

  • 482 carats recovered from 299 tonnes of kimberlite for grade of 161cpht (+1mm)
  • Diamonds recovered of 15.8ct, 10.45ct, 5.5ct and 4.85ct, with 44 stones greater than 1ct
  • Two kimberlite samples weighing a total of 296kg submitted for microdiamond analysis
  • Resource to be calculated on initial 500m section of 5km long Katcha Dyke
  • Katcha is adjacent to the Droujba Pipe which has a JORC Compliant resource of 2,474,000cts

Chief Executive Karl Smithson commented:

“The high grades from bulk sampling at the Katcha Dyke demonstrate its potential to enlarge the Droujba project resource base. The presence of several large near gem quality diamonds up to 15.8 carats in size from this relatively small diamond parcel is further cause for encouragement.

“Bulk sampling is on-going at the Droujba Pipe in order to obtain a 2,000 carat parcel for valuation. We remain on track to complete this programme this month in order that an independent resource statement can be prepared which will include the 500m drilled section of the Katcha Dyke.

“Considerable progress has been made in recent months on our priority Tongo and Droujba kimberlite projects and we look forward to updating shareholders as we progress.”

Katcha Bulk Sampling and Results

As announced on the 6th August 2012, a series of bulk samples were collected from a 100m strike length of the Katcha Dyke located some 600m to the northwest of the Droujba Pipe. All these samples have now been processed and the results collated (see table below).

A total of five samples comprising 299.14 tonnes of in-situ kimberlite material have been collected and processed by the Company’s on-site 5 tonne per hour DMS plant with diamond recovery being by X-Ray Flowsort under observation from the Government mines observer. These samples were collected from the same section of the Katcha Dyke at approximately 20m intervals over a total distance of 100m. The kimberlite dyke varied in average width from 41cm to 141cm over the five 20m sections that were sampled. Each sample was carefully measured and its density and moisture content calculated so that the in-situ kimberlite tonnage could be accurately determined.

The processing yielded a total of 482.45 carats from the 299.14 tonnes of kimberlite to give an in-situ kimberlite grade of 161.28cpht (+1mm) for the composite five samples. Some 44 stones of greater than one carat were recovered, with 14 of these weighing in excess of two carats. The largest stones weigh 15.8ct (near gem), 10.45ct (rejection), 5.5ct (gem), 4.85ct (rejection). The diamonds will be exported to Antwerp in the near future for valuation.

Sample Dry Tonnes processed Carats Recovered +1mm dry grade (cpht)
Katcha Bulk Sample KBS-1A 21.22 47.50 223.84
Katcha Bulk Sample KBS-1B 29.41 53.25 181.06
Katcha Bulk Sample KBS-1C 41.36 72.15 174.44
Katcha Bulk Sample KBS-1D 86.66 118.65 136.91
Katcha Bulk Sample KBS-1E 120.49 190.90 158.44
Totals and average grade 299.14 482.45 161.28

Microdiamond Sampling

Processing of two sets of microdiamond samples is ongoing at the Saskatchewan Research Council laboratory in Canada, with results expected in the near future. These samples comprise 250kg (wet weight) of kimberlite collected from the surface trench of the bulk sampling and 46kg (wet weight) of kimberlite core collected from the seven drill holes that intersected the Katcha Dyke.

Updated Resource Statement

CAE Mining Africa has been retained to provide an updated resource statement for the Droujba project taking into consideration the additional bulk sampling information for both the Droujba Pipe and Katcha Dyke, and in terms of Katcha the drilling information and the microdiamond analysis.

As announced on the 2nd April 2012, the Droujba project currently has a JORC compliant inferred resource of 2.474 million carats for the Droujba Pipe only to a depth of 360m, with a modeled resource grade of 70cpht and average modeled diamond value of $60 per carat.

In accordance with the AIM Rules for Companies, the information in this announcement has been reviewed by Karl Smithson, Chief Executive of Stellar, a qualified geologist and Fellow of the Institute of Materials, Metals, Mining, with 23 years’ experience.

About Stellar Diamonds plc

Stellar is a London (AIM: STEL) listed West African focussed diamond mining and exploration company which is advancing the Droujba kimberlite pipe in Guinea and the Tongo kimberlite dyke project in Sierra Leone, which combined have a JORC Compliant, inferred diamond resource of 3.1 million carats. The Company recently announced a dispute with the Ministry of Mines in Sierra Leone over its two Kono licences.

For further information please contact the following or visit the Company’s website at www.stellar-diamonds.com.

Stellar Diamonds plc

Karl Smithson,Chief ExecutiveTel: +44 (0) 20 7257 2930

Northland Capital Partners Limited

(Nominated Advisor and Broker)

Gavin Burnell, Edward Hutton Tel: +44 (0) 20 7796 8800

Daniel Stewart & Company plc

(Co-Broker)

Martin Lampshire, Antony Legge Tel: +44 (0) 20 7776 6550

Pelham Bell Pottinger

James MacFarlane, Joanna Boon Tel: +44 (0) 20 7861 3232