(TheNewswire)
Highlights
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Diamonds retrieved by caustic fusion of drill core fromthe Sequoia kimberlite show a relatively abundant presence of lownitrogen diamonds, some of which contain deep, high-pressure mineralinclusions.
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Recent research globally, by academia, demonstratesthat most of the world’s larger high-priced diamonds arenitrogen-free (Type II) and are deep-sourced (400 km).
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This study adds to the lines of evidence that justifiesacquisition of a bulk sample, large enough to give a “window” intowhat the run of mine would be valued at. Information required tounderstand the economic potential.
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Research reported here, carried out at the Universityof Alberta, is to be presented at the upcoming Kimberlite Conferencebeing held in Yellowknife, in July.
June 27 th, 2024 – TheNewswire - Vancouver, British Columbia– Arctic Star Exploration Corp. (“Arctic Star” or the “Company” ) (TSXV: ADD)(Frankfurt: 82A2) (WKN: A2DFY5) (OTC: ASDZF) is pleased to announcethat it has received results from research carried out at theUniversity of Alberta by Dr. Luisa de Carvalho under the guidance ofThomas Stachel and Graham Pearson. The interpretation of the resultsare of soley the opinion of the company, however the authors agreeit’s a possible indication that larger gemstones will bepresent.
The diamonds recovered by caustic fusion from severaldrill holes were transferred to the University from the SRClaboratories in Saskatoon under an unbroken chain of custody.
Seventy-three (73) of these diamonds were selected forfurther study based on their size (>700 µm; n = 51) or thepresence of visible mineral inclusions (n = 22). The diamonds wereanalyzed for their nitrogen content and aggregation state and fortheir C and N isotope compositions. Mineral inclusions from 224diamonds were also analyzed.
Of the studied diamonds, 27% are fragments, 26% areaggregates/twins, 18% are octahedra, 18% are roundeddodecahedra/resorbed, and 11% are macles.
The colors of monocrystalline diamonds are mainly white(43%), pale yellow (48%), or brown (9%). Six of the diamonds arefibrous, highly resorbed, and black/dark grey (n = 4), white (n = 1),and yellow (n = 1) in color.
Figure 1 shows pie graphs comparing the FTIR resultsfrom this study on Sequoia diamonds to published data on diamonds fromother Lac de Gras kimberlites.
Figure 1: Distribution of diamondtypes for the Sequoia kimberlite compared to the Lac De Graskimberlite field (Central Slave), as determined bymicro-Fourier-transform infrared spectroscopy (µ-FTIR). Figure fromCarvalho et al. (2024). See reference below.
Study of the mineral inclusions shows that Sequoiakimberlites tapped both lithospheric and sub-lithospheric mantlesources of diamonds beneath the Slave Craton, with peridotite beingthe principal diamond-bearing substrate. Five of the diamonds belongto the sub-lithospheric suite based on the presence of ferropericlase± olivine, breyite, or larnite ± olivine, mineral associations thatonly form under intense pressure. The mineral inclusions were analyzedby Raman Spectroscopy. All of the diamonds classified assub-lithospheric are either Type IaB or IIa.
For the complete parcel of Sequoia diamonds studied,the analyses have revealed that 37% of the diamonds aresub-lithospheric in source, 26% are Type IIa (no detectable nitrogen),and 11% are Type IaB. Figure 1 compares the population of stonesstudied from Sequoia with the published distribution of diamond typesfor the Lac De Gras kimberlite cluster.
Mr. Buddy Doyle, VP Exploration of Arctic Star,commented, “ Recent work by the diamondresearch community has revealed that many of the larger than 10ctdiamonds of exceptional quality found around the world are deeplysourced ( hundreds of kilometers ),nitrogen - free stones,classed as Type IIa. Figure 1 illustrates that Sequoia contains a highproportion of these stones in comparison with other kimberlites in theCentral Slave kimberlite province. When compared to the total diamondsmined and studied globally, they are even rarer, making up only a few percent of the total.Also present is a significant population of Type IaB low - nitrogen diamonds which are alsorelatively rare and sourced from great depths. Studying inclusions in these diamonds revealsminerals that only form under ultra-high pressure, confirming they arecoming from great depths. ”
Mr. Doyle continues, “ There arealso further layers of evidence that hint that the Sequoia kimberlitecomplex may harbor large exceptional diamonds. These are : (1) The diamonds liberated by the causticfusion from the drill core to date demonstrate a population size frequency curvethat has a relatively low gradient, meaning the ratio of larger stonesto smaller stones is higher than the average. If this relationshipholds strong as we increase the sample size, it predicts that largerstones will be encountered.
(2) The relative lack of recovered boart material when compared withcaustic fusion diamond results from other kimberlites in the Lac deGras field . Here, only afew percent are boart , whereas on average the boart dominates at >50 percent .
(3) The indicator mineral chemistry presented by Dr. Chuck Fipke , where he reports an abundance oflherzolitic and deep - sourced indicator minerals from Sequoia. ”
Due to their exceptional value, even getting one +10ct‘special’ stone per 100,000 tonnes of kimberlite can significantlyaffect mine economics. Arctic plans to take a bulk sample ofapproximately 3000t, timed for winter 2026. Even at this size ofsample, some luck would have to be involved to “see” such largestones. This size sample, limited by cost and logistics, is designedto give a good first estimate of the average value of the “run ofmine” stones. If the economics from this sample prove robust on therun of mine stones alone, then every time a larger stone reports, itwould be welcome bonus. The size distribution of the diamonds from theproposed bulk sample, and any variation in the quality of the stonescompared from different size classes, will allow us to gain a greaterunderstanding.
Sequoia is part of the large Lac de Gras kimberlitecluster (Central Slave group), a geographic grouping of over 200separate kimberlites that all erupted in a 20-million-year timeperiod, centered around 55 million years before present. Of these,about a dozen are mined or considered for mining, and there is publicinformation on their economics. They vary in their realized averagerun of mine aggregate diamond values, with prices ranging from /ct to 420/ct (2014 prices). Assuming the Sequoia kimberlitecomplex has an average grade of circa 0.3 ct/t (estimated byprojecting the size distribution of the caustic fusion recovered smallstones into commercial stone space, an estimate that will be refinedand become more certain as we take more samples). Sequoia would needto demonstrate it contains diamonds averaging > 200/ct in valueto trigger a feasibility study. There are kimberlites in the clusterwith these grades and valuations, so it is not unreasonable toconsider Sequoia may have this potential.
The next planned step is to complete the first passdelineation of the Sequoia kimberlite complex with HQ size drilling tofurther understand the diamond distribution and geology. Approximatelyfifteen, 200m holes are planned for spring 2025. The delineation workso far (8 holes) has revealed several different kimberlite varieties,each with the potential to have different diamond populations.Completion of this work will help in the design of the bulksample.
Of note, in a previous news release, Arctic reported asample containing 51% Type IIa diamonds, a higher percentage thanreported here. This may be due to a number of reasons. First, theoriginal study looked at diamonds down to 0.3mm in size, and second,only looked at diamonds from the first two holes. This study looked atmaterial from all drill holes and only stones >0.7mm. Third, thefirst two holes had a different mix of kimberlites to the other drillholes; there might be a kimberlite type that has an enhanced Type IIapopulation. This requires further work to gain understanding.
Mr. Doyle concludes, “Diamonds are the ultimatesampling challenge in the mining industry. Taking a bulk sample is anexpensive hurdle; however, once that hurdle is crossed, the pathway toproduction is usually less capital-intensive than that of othercommodities, especially if we can leverage the existing mininginfrastructure in this world-class diamond district.”
Dr. Carvalho will present the work reported here at theQuadrennial Kimberlite Conference, being held in Yellowknife, thisJuly 2024. At which core from the Sequoia Kimberlite complex will beon display. The reference for the extended abstract is givenbelow.
Carvalho, L.D.V., Doyle, B., Stachel, T., Pearson, G.(2024). A first look at diamonds and their inclusions from the SequoiaKimberlite Complex, Northwest Territories, Canada. Extended Abstract(150), 12th International Kimberlite Conference, Yellowknife.
Arctic Star thanks the University of Alberta for thisinteresting contribution and looks forward to continuing studies andfurther collaboration.
About Arctic Star
Arctic Star is predominantly a diamond explorer,recently discovering 5 new kimberlites in the prolific Lac De Graskimberlite field that supports 2 multi-billion dollar kimberlitemining complexes. The Company also has a 958 Ha Exploration permitcontaining several diamond-bearing kimberlites on its Timanttiproject, Kuusamo Finland. The Company continues to look forappropriate diamond opportunities elsewhere.
ON BEHALF OF THE BOARD OF DIRECTORS OF
ARCTIC STAR EXPLORATION CORP.
“Patrick Power”
Patrick Power, President & CEO
+1 (604) 218-8772
ppower@arcticstar.ca
This news release contains“forward-looking statements” including but not limited tostatements with respect to the Diagras Joint Venture. Forward-lookingstatements, while based on management’s best estimates andassumptions, are subject to risks and uncertainties that may causeactual results to be materially different from those expressed orimplied by such forward-looking statements. There can be no assurancethat such statements will prove to be accurate, as actual results andfuture events could differ materially from those anticipated in suchstatements. Accordingly, readers should not place undue reliance onforward-looking statements. Arctic Star undertakes no obligation or responsibility to updateforward-looking statements, except as required by law.
Neither the TSX Venture Exchange norits Regulation Services Provider (as that term is defined in thepolicies of the TSX Venture Exchange) accepts responsibility for theadequacy or accuracy of this release.
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