“The industry uses caustic fusion microdiamond results to determine if the kimberlite is diamond bearing and use the number of stones per tonne, or frequency, and the size distribution to prioritise further work. If there are sufficient sample, grades can be predicted. Usually, the higher the number of stones per weight equates directly to high grades. Also important for grade is how quickly the diamond counts decay from the smaller sieve size to the next largest. In this batch of results, we see the decay flattening with and unexpected larger number of stones >0.3mm. With two 0.6mm stones reporting. The Arbutus kimberlite could well be of economic interest if this trend continued, into larger stone sizes. The only way to determine this is to fetch more sample by future drilling.” The laboratory also provided descriptions of all diamonds 0.3mm in diameter and greater, of which there were 8. Of these, 2 are grey and translucent, 5 are white to off white, and 1 is yellow. All are described as aggregates or fragments. Please note these stones are too small to be consider gem, economic stones are >1.18mm in diameter.
Table 1. Caustic Fusion Results: All Diagras Discoveries descending order of stones per 100/kg
| Kimberlite | 0.105 mm | 0.15 mm | 0.212 mm | 0.3 mm | 0.435 mm | 0.6 mm | 0.85 mm | 1.18 mm | Weight Kg | Total Stones | Stones/ 100kg |
| Sequoia | 282 | 117 | 39 | 23 | 10 | 6 | 1 | 1 | 505.3 | 499 | 99.8 |
| Arbutus | 29 | 19 | 5 | 2 | 4 | 2 | 0 | 0 | 143.05 | 61 | 43 |
| Birch | 10 | 7 | 7 | 3 | 1 | 1 | 0 | 0 | 141.5 | 29 | 20 |
| Alder | 3 | 6 | 1 | 2 | 1 | 0 | 1 | 0 | 223.72 | 14 | 6 |
| Cedar | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 90.6 | 1 | 1 |
A chain of custody protocol was used. Sample weights are dry weights. A total of 143.05 kg of half NQ core, from drill hole 8 and full core from drill hole 9 consisting of 18 samples weighing on average 7.9kg, where sent to the Saskatchewan Research Council laboratory, in Saskatoon. There they undergo a caustic fusion process where the samples are fused in kilns under heat for 24 hours to form a residue. The residue is then further chemically treated, the final product is then hand-picked for diamonds utilizing a microscope. Each sample is spiked with distinct artificial diamonds to ensure good recovery. The Laboratory is SCC accredited, (ISO/IEC 17025).
The Arbutus Kimberlite is adjacent and to the south of the Finlay kimberlite discovered in the 1990’s. Previous workers drilled serval holes into Finlay but never made the results public. With Arbutus proving diamond positive the JV now plans to test Finlay for diamonds.
The JV awaits the diamond results from the Spring drilling program on Sequoia these should become available over the next weeks. Once these diamond results are in hand the JV will be able to scope further work and Sequoia. The JV also plans to continue to explore for new kimberlites on the property in 2023
arctic-star-announces-diamond-results-for-the-arbutus-2022-kimberlite-discovery