Following the establishment of a joint venture in December 2013 over a 1km² exploration licence which incorporates the five hectare diamondiferous Baoulé kimberlite pipe in the Aredor region of central Guinea, Stellar commenced the treatment of weathered kimberlite ore for a 100,000 tonne trial mining evaluation programme in October 2014. During 14 months of actual production over 11,000 carats have been recovered from this large scale bulk sampling project to date. Once the target of 100,000 dry tonnes has been processed a preliminary resource estimate will be prepared which will determine the next phase for this project.
BAOULE KIMBERLITE PIPE
An in-house geological modelling exercise has been carried out using the previous drilling data which suggests a target of over 22 million tonnes to a depth of 300m (non-JORC). At the current evaluation grade of this would suggest a diamond resource of approximately 3 million carats contained within the 22 million tonnes.
An in-house geological modelling exercise has been carried out using the previous drilling which suggests a target of over 22 million tonnes to a depth of 300m (non-JORC). At the current evaluation grade of 13.4cpht (+1.25mm cut off) this would suggest a diamond resource of approximately 3 million carats contained within the 22 million tonnes.
The Baoulé kimberlite pipe comprises two lobes. The figure below highlights the west lobe:
The East lobe is depicted in the figure below:
BAOULE EVALUATION STRATEGY
Stellar believes the previous limited bulk sampling was not fully representative of such a large pipe in an area renowned for its large top gem quality stones recovered from downstream alluvial deposits. As part of the Joint Venture Agreement, the Company relocated its 100tph DMS plant with Flowsort final recovery from Mandala to Baoulé together with the crushing sections of the former Droujba bulk sampling plant which were then modified and integrated to process the weathered kimberlite as part of a trial mining exercise. The objective has been to not only determine the grade and value with confidence but also assist Stellar with cash flow for the evaluation work. Furthermore, the previous diamond value was based on a relatively small parcel which contained no recorded large diamonds, which was sold over 13 years ago.
The Baoulé kimberlite is one of the largest (5Ha) of the potentially large stone, primary sources in Guinea and in order to estimate the diamond population of the entire kimberlite a suitably large bulk sample must be extracted.
CURRENT WORK PROGRAMME
Between October 2014 and June 2015 approximately 50,000 dry tonnes were extracted and processed from the East lobe of the Baoulé kimberlite. Preparation of the west lobe commenced following a hiatus during the height of the wet season (mid 2015). By November 2015, mining and processing of the west lobe kimberlite was well underway. To date some 43,000 dry tonne has been treated from this lobe.
Photo of the West lobe during the excavation of first cut from this part of the kimberlite pipe
Over 11,000 carats have been recovered to date realising in a gross revenue in excess of US$ 1 million. The largest diamond recovered to date weighs 55 carats, which although of low quality, does indicate a large stone potential for this pipe.
SUMMARY OF DIAMOND SALES FROM THE BAOULE KIMBERLITE
Stellar has held three diamond sales totalling 8,465 carats which realised over US$1 million in revenue.
The average diamond price between the sales varies from US$92 to $156 per carat depending on the mix and presence of larger gem quality stones. Some high value gems are present, including a 10 carat fancy yellow which sold for an average price of $6,800 per carat.
A selection of the diamonds sold during the three sales events are shown in the photos below: