The Sheahan Diamond Literature Reference Compilation is compiled by Patricia Sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcements called the Sheahan Diamond Literature Service that is distributed as a free pdf to a list of followers. Pat has kindly agreed to allow her work to be made available as an online digital resource at Kaiser Research Online so that a broader community interested in diamonds and related geology can benefit. The SDLRC Blog is a guest commentary by an industry expert about articles, themes and trends in recent issues of the SDLRC.
Comments by Brooke Clements
Brooke Clements is President and CEO of Craton Minerals Ltd., a Vancouver-based private diamond exploration company focused on discovering North America's next diamond district. He is also President of JBC Ventures Ltd., a consulting company specializing in mineral exploration and community and government relations. From 2007 to 2015 he was President of Peregrine Diamonds Ltd. where he led the team that discovered the Chidliak diamond district on Baffin Island in the Canadian Arctic. Before that, Brooke was Vice President, Exploration for Ashton Mining of Canada Inc. Under his leadership, Ashton and their partner SOQUEM discovered the Renard diamond district in Quebec where the Renard Diamond Mine commenced production in 2016. From 1982 to 1997, Brooke was an Exploration Geologist and Regional Manager for Exmin Corporation where he conducted diamond exploration programs throughout the United States. He holds a BSc in Geology from Indiana University and an MSc in Economic Geology from the University of Arizona.
Brooke Clements has volunteered to highlight the articles that caught his attention in the monthly reference compilations. The opinions expressed are solely his and he can be reached at .
This is an interview in Gems and Jewelry with the interim President of YoGold USA, owner of the famed Yogo sapphire mine in Montana where unique blue sapphires are mined. Unlike other sapphire mining in Montana, which exploits alluvial deposits, Yogo is focused on mining a mafic dyke. In 2020 and 2021, the dyke was mined at the surface. They are now rehabilitating the underground workings and hope to start underground mining in May with an ultimate goal of about 135 tonnes production a day. Yogold has established a cutting facility dedicated to its production in Sri Lanka.
This article in Gems and Jewelry discusses large diamonds and the increased frequency at which they are being found. Out of 88 documented diamonds weighing 200 carats or more, 36 (41%) have been found since 2015. Of those 88 stones, Letseng in Lesotho has produced 12, seven since 2015, and Karowe in Botswana 19, 17 between 2015-2020. Much credit for the recent large stone recoveries is given to x-ray transmission (XRT) which helps reduce breakage of larger stones. XRT was developed for the diamond industry by TOMRA. Letseng began using the technique in 2011 followed by Karowe in 2015.
A detailed study of the different types of coherent kimberlite found in kimberlites in the Lac de Gras kimberlite field in the NWT. Coherent kimberlite occurs as low-volume unfragmented dykes and probable sills and medium-high volume pipe-filling coherent kimberlite. The authors conclude that distinct primary melt compositions were largely responsible for the differences in emplacement styles of the coherent kimberlite. Figure 1, available for viewing at the following link, is a good map of the Lac de Gras field showing the kimberlites where coherent kimberlites samples were used for this study.
The scheduled closure of the Diavik diamond mine in 2025 will be a great loss for the economies of the NWT and Yellowknife. The mine opened in 2003 and it accounts for about 10% of GDP in the NWT. Diavik is forecasted to produce between 5 and 6 million carats of diamonds this year, or about 4% of world production.
While the USA has outlawed trade with ALROSA, there are still not official restrictions on Russian diamonds that are cut and polished outside of Russia. However, to address consumer concerns, many cutters, polishers and wholesalers are beginning to segregate their diamonds into diamonds of Russian and non-Russian origin. This will probably result in non-Russian diamonds trading at a premium to Russian goods and a reduction in the export of Russian diamonds.