Following the establishment of a joint venture with a local company in December 2013 over a 1km² exploration licence incorporating the five hectare diamondiferous Baoulé kimberlite pipe in the Aredor region of central Guinea, Stellar commenced the treatment of weathered kimberlite ore in October 2014. By June 2016 and 14 months of actual production, Stellar’s local company, Ressources Tassiliman Baoulé (RTB), completed the targeted 100,000 dry tonne trail mining programme recovering some 11,808 carats and realising $ 1.2M in revenue from diamond sales.
In July 2016, negotiations began with Dubai based Citigate Commodities Trading culminating with the signing of a new JV Agreement in October 2016 (announced on 9th November 2016) whereby Citigate through phased incremental investments of up to $ 8.5M aims to bring the deposit to the level of Pre-Feasibility commencing with the continued trial mining of the East Lobe (50,000 tonnes) where the better results were derived.
BAOULE KIMBERLITE PIPE
An in-house geological modelling exercise was carried out in 2014 using the previous drilling, suggesting a target of over 22 million tonnes to a depth of 300m (non-JORC). At an evaluation grade of 13.4cpht (+1.25mm cut off) this would suggest a diamond resource of approximately 2.88 million carats. 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 needed to be extracted.
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 took the view that 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 original Joint Venture Agreement, the Company relocated its “in country” 100tph DMS plant (with Flowsort final recovery) and modified it to process the weathered kimberlite as part of a trial mining exercise.
While a previous diamond value was based in 2000 on a relatively small parcel, which contained no recorded large diamonds, the current work aimed at determining with confidence the grade and diamond value of the deposit.
COMPLETED WORK PROGRAMME & RESULTS
Trial mining evaluation of the Baoulé kimberlite pipe was completed, through the mining, extraction and processing of over 100,000 dry tonnes of kimberlite, in June 2016. The geology of the pipe is complicated in parts with what seem to be multiple intrusions and brecciated contact zones in both the East and West Lobe, with the western lobe in particular hosting a number of late stage and cross-cutting kimberlite dykes. For the purposes of evaluation it was not possible to separate and process separately each kimberlite lithology. However, the east and west lobes were sampled and processed separately, which did confirm a difference in grade between the two.
From some 46,561 tonnes processed from the eastern lobe and 56,555 tonnes processed from the western lobe, a total of 11,808 carats were recovered from the initial trial mining with a +1.25mm cut off, giving an average grade of 11.4cpht. However, it is clear that the eastern lobe has a higher grade at 13.3cpht than the western lobe at 9.8cpht. This could be a consequence of different kimberlite types or processing efficiencies, since it was noted that the western lobe did yield a fewer percentage of -7 sieve stones (<1.83mm) compared to the eastern lobe.
A total of 929 stones greater than 1 carat were recovered including numerous high value gem and fancy coloured (yellow) diamonds of up to 12 carats in size. Additionally a one 55 carat stone was recovered, which confirms the Company’s belief that the Baoulé pipe is a source of large diamonds. The results show a clear difference in grade and diamond quality between the eastern and western lobes, with the volumetrically larger eastern lobe being of higher grade and quality.
The table below sets out the diamond processing results to date from Baoulé:
|Sample||Diluted Dry Tons||Carats||+1.25mm Grade (cpht)||Number of Diamonds||Diamonds greater than
|Diamonds greater than
|Largest Diamond (carats)|
SUMMARY OF DIAMOND SALES FROM THE BAOULE KIMBERLITE
Export 1 & 2:
- 8 cts of better quality Baoulé goods were sold for an average of $ 266 / carat
- A RoM average price of $ 110.5 / carat was derived solely from the East lobe
- The rough market was considered weak at the time of sales with prices down by 15 – 20%
- 4,439.3 carats were auctioned following viewings in Antwerp & Dubai
- A RoM average price of $ 156 / carat derived solely from the East lobe
- Rough market was considered to have been robust at the time of sale
- 3,291.5 carats were auctioned following viewings in Antwerp
- A RoM average price of $ 91.05 / carat was derived mostly from West lobe goods
- Sentiment in the rough market was considered to subdued at the time of sale
- 3,137 carats were auctioned following viewings in Antwerp
- A RoM average price of $ 72.65 / carat was derived mostly from West lobe goods
- Sentiment in the rough market was considered to be negative due to lack of confidence with banks and liquidity issues in the midstream diamond processing
Some 11,602 carats have been sold to date generating revenues of approximately $ 1.2M.
JOINT VENTURE WITH CITIGATE COMMODITIES TRADING
A heads of terms was signed between Stellar Diamonds Plc and Citigate Commodities Trading in July 2016 culminating in the signing of a new Joint Venture between local company, Tassiliman sarl, Stellar Diamonds plc and Safa Afrique Ltd (Citigate’s African subsidiary company) in late October 2016. This was announced on 9th November 2016. The terms of the JV are detailed below:
Highlights of the Baoulé Joint Venture:
- Staged earn-in by Citigate’s subsidiary company SAFA Afrique Ltd. of up to 75% of Baoulé;
- Phase-1 expenditure of US$1.5 million for a 25% shareholding
- Phase-2 expenditure of US$2 million for a further 25% shareholding
- Phase-3 fund a pre-feasibility study for a further 25% shareholding
- Stellar to be paid a Phase-1 management fee of US$150,000
- Stellar to receive 56% of gross revenues from Phase-1 trial mining
- Citigate awarded off-take rights on goods exported during the Citigate earn-in process
PHASE I OBJECTIVE
Following the encouraging results determined from the East Lobe, the joint venture partners have agreed to extract a further 50,000 dry tonnes from the more interesting of the two lobes, i.e. the East Lobe as part of the Phase I programme. While the grade has been successfully determined at 13.34 cpht during the initial trial mining, it is hoped that additional large high value stones will be recovered from this work which will greatly enhance the viability of this deposit and perception of the project.
The remaining phases intend to achieve the following:
Phase 2 will involve drilling and microdiamond sampling at the Property in order to deliver an Indicated Resource of the Baoulé kimberlite pipe to a depth of at least 300m but up to 500m in order to target a Resource of between 3 and 5 million carats. The programme will commence concurrently after Phase I and is anticipated to last for a period of 2 years and will require an expenditure of $ 2M.
Phase 3 will be dependent upon the work completed during Phase 2, and will entail the work required for and the delivery of a report prepared by an internationally recognised independent consultant which will take the project to the level of a Pre-Feasibility Study. Phase 3 will commence upon the completion of Phase 2 and will take up to a period of 3 years with a budget of $ 5M.