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An Insight into the Discovery of the Argyle Diamond Mine

Mineral exploration is a complex and evolving field that has undergone significant advancements over the years. It involves a meticulous process of discovery, as exemplified by projects like Olympic Dam, which required almost two decades of planning and a decade of execution. The understanding of geology and manually handling exploration techniques, which was once laborious and time-consuming, is rapidly becoming obsolete.

one noticeable trend in the exploration industry is the decline of diamond exploration, Photo by Sabrianna, Unsplash | Samso Insights  | Samso
one noticeable trend in the exploration industry is the decline of diamond exploration

In the rapidly evolving landscape of decarbonisation and clean energy, it's understandable that investors and geoscientists may prioritise exploring commodities like lithium and more recently, rare earth elements.

The field of mineral exploration has undergone significant changes since I entered it in 1992. The methods and technologies we use have evolved dramatically over time. However, one noticeable trend in the exploration industry is the decline of diamond exploration.

In this episode of Samso Insight 113, we delve into a captivating discussion with Thomas Reddicliffe about the extensive search for the largest diamond mine. It's a topic that has intrigued many over the years, and we're excited to bring you this insightful conversation. If you've been following Samso, you might recall our previous discussion on the discovery of Olympic Dam. That was quite a journey in itself, and now we have the opportunity to explore the world of diamond exploration with Thomas Reddicliffe.

Thomas joined the scene in 1976, towards the end of the discovery process. He provides us with a fascinating narrative of the glory days of diamond exploration and brings us up to speed on recent developments, from even just a few years ago. It's truly a remarkable journey that he shares with us. Of course, there are many other thought leaders who could have contributed to this Samso Insight, and these will come in time. For now, we are lucky to have Thomas with us, so we hope you enjoy this episode and gain valuable insights into the world of diamond mining.

The inspiration to get Samso Insight Episode 113 completed is my appreciation of what it took to discover Argyle. The book by Stuart Kells entitled "Argyle - The Impossible Story of Australian Diamonds" which you can purchase on Amazon or Melbourne University Press (MUP) , was the impetus for my eagerness to try and document as much as I can to make sure the story is on the Samso Platform.

Samso's Conclusion

Diamond exploration is a specialised form of mineral exploration that is facing challenges and changes that involve non-geological factors, particularly in "developed" jurisdictions. Diamonds have long captivated people of all ages and are widely recognised as one of the most well-marketed commodities in the world.

Diamonds are crystalline forms of carbon that are created deep within the Earth under high temperatures and extreme pressures. At surface air atmospheric pressure (one atmosphere), diamonds are less stable than graphite, and therefore, the thermodynamic conditions favour the decay of diamond (δH = -2 kJ/mol). Historical records indicate that diamonds were known to burn during Roman times (Magill School of Computer School). It is worth noting that the marketing efforts of De Beers have played a significant role in establishing and sustaining the diamond market.

Diamonds, regardless of scientific knowledge, are cherished and adored today as a beautiful crystal that brings joy to everyone. From the perspective of a geoscientist, the search for diamonds holds great excitement and intrigue.

I consider myself fortunate to have entered the field during a time when diamond exploration was at its peak. In the 1990s, the quest for diamonds was in its final decade of glory, and the expertise of many experienced practitioners has since become scarce. The individuals who had mastered the art of diamond exploration are now approaching the end of their careers, and I worry that their valuable skills will be lost.

While new geoscientists will undoubtedly acquire the necessary knowledge and techniques through a structured learning process, there are certain intangible skills that can only be honed through years of practice. It is these skills that I fear may be forgotten, and relearning them would be akin to reinventing the wheel.


00:00 Start

00:20 Introduction

02:10 Diamond exploration - a discussion

03:19 Rundown of the search in 1973

10:04 Pragmatic approach to exploration

11:27 Treating indicator minerals for analysing

13:12 Ellendale discovery

16:27 Lamproites and Kimberlites

19:26 Discussion about the economic side

22:06 The situation after Ellendale

24:12 Was there a difference between indicator minerals?

26:05 The last 10 years of active diamond exploration

27:15 Would the technology today help with the exploration cost?

28:19 Was stream sampling more effective?

29:25 Is there still an “Argyle” today?

34:36 Discussion about Argyle

42:21 The future of the diamond industry

53:17 Conclusion


About Thomas Reddicliffe

BSc (Hons) Geology University of Queensland, 1974

MSc Ore Deposit Geology University of Western Australia, 1999

Mr Tom Reddicliffe has over 40 Years of largely Australian focused exploration, evaluation and feasibility experience over a range of commodities but with a focus on diamonds.

He commenced his career as a field geologist with Ashton Mining Ltd and was involved in the early Kimberley (Aust) diamond exploration with the AEJV (Ashton Exploration Joint Venture) which led to the discoveries of the Ellendale and Argyle diamond deposits, and was also involved in the early evaluation of both deposits.

Subsequently he became the Australian Exploration Manager for Ashton Mining Ltd and held this position for 16 years until Ashton was taken over by Rio Tinto in 2001. During this time he conceived and implemented the exploration which resulted in the discovery of the Merlin kimberlite field and was responsible for the initial evaluation of the diamond deposit.

Mr Reddicliffe was a senior executive of Striker Resources/North Australian Diamonds Ltd, was appointed to the Board as Technical Director in 2004 and became CEO in 2007, a position he held until 2011. NADL, later to be renamed Merlin Diamonds, was focused on the evaluation of the Merlin diamond pipes.

In 2007, he also assisted in the spinout and successful listing of NADL subsidiary company Top End Uranium and subsequently became CEO. Striker Resources/North Australian Diamonds (NADL) provided 10 years of small company corporate experience inclusive of promotion, capital raising, investor relations, new floats, and defending the company from takeover bids.

In 2012 Mr Reddicliffe joined GeoCrystal Limited, an unlisted public company, as Technical Director and directed the company’s diamond exploration activities which were focused on the newly discovered Webb kimberlite field located in central Australia. He stepped down from the board in 2022.

Mr Reddicliffe joined the Sorrento Resources group in 2019 to manage their diverse range of gold, iron ore, nickel, diamond and mineral sand projects.

He joined the board of Errawarra Resources Limited (ASX: ERW) as a non-executive director upon its listing in late 2020 and was appointed Executive Chairman in 2022. Errawarra is a gold and nickel focused explorer.

He is a foundation Executive Director of GreenTech Metals Limited (ASX: GRE) which listed in early 2022 and which is focussed on the exploration for battery minerals He is also a non-executive Director of Gibb River Diamonds in early 2020.



The information or opinions provided herein do not constitute investment advice, an offer or solicitation to subscribe for, purchase or sell the investment product(s) mentioned herein. It does not take into consideration, nor have any regard to your specific investment objectives, financial situation, risk profile, tax position and particular, or unique needs and constraints. Read full Disclaimer.

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