Newfield Resources continues to hit paydirt at its Tongo concessions in eastern Sierra Leone. The Perth-based budding diamond producer has unearthed more “gem-quality” diamonds in the Peyima kimberlite located only 5 kilometres southeast of the current mine development on the Kundu and Lando kimberlites where production is slated to commence in the early months of 2022.
The Tongo diamond project covers approximately 134 square kilometres in eastern Sierra Leone, an area renowned for high quality diamonds. To date, 11 diamond bearing kimberlites have been identified at the project, of which only 5 have been incorporated into the current JORC-compliant, 8.3 million carat diamond resource estimate.
With a maiden mineral resource reported on the Panguma kimberlite earlier this year, Newfield quickly turned its attention to the previously discovered Peyima kimberlite.
The Peyima kimberlite has historically been subject to artisanal mining and is therefore known to be diamondiferous.
According to the company, the Peyima kimberlite has been mapped along surface over a distance of more than two kilometres. A limited drilling programme conducted in 2010 resulted in three holes from a four-hole programme intersecting kimberlite, with the deepest intersection being 130 metres vertical depth from surface.
Newfield previously reported it had undertaken a bulk sampling exercise of the Peyima Kimberlite for a first-pass assessment on the diamond grade and quality of the body.
The initial evaluation programme was completed through the collection and processing of a 108 dry tonne sample which yielded 110 carats of diamonds, for an encouraging sample grade of 102 carats per hundred tonnes – or “cpht”.
Encouragingly, over 70 per cent of the recovered diamonds were categorised as gem or near-gem quality with the largest stone weighing in at a handsome 5.07 carats.
Overall, Tongo has 63 per cent gem content compared to 20 per cent for average worldwide diamond mines according to diamond specialist Ray Ferraris in a 2019 report prepared for Newfield.
Newfield Resources Executive Director Karl Smithson said:
“This first assessment of the Peyima Kimberlite diamond grade and quality is highly encouraging and supports the further work which will include the processing and analysis of a 182kg microdiamond sample to better assess the grade potential of the kimberlite. Initial independent valuation of the recovered diamond sample confirmed diamond value consistent with the Kundu and Lando Kimberlite in the smaller sieve classes.”
The company says the results are only a preliminary grade estimate based on a small sample and are not sufficient to plug into a mineral resource estimate at this stage. To establish a JORC compliant mineral resource, further drilling, bulk sampling and microdiamond analysis is needed.
Newfield’s 8.3 million carat resource is hosted in just 5 of the known 11 kimberlites on its Tongo concessions. As the company lays plans to systematically explore and drill test each of the kimberlites, market observers will be keen to see if it can add more gems to a purse already brimming with diamonds.
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By Matt Birney
