In conversation with David Rhys

May 17, 2023
David Rhys
David Rhys
Consulting Geologist at Panterra Geoservices

David Rhys is a Consulting Geologist based in Vancouver, Canada, who applies geological studies with a structural focus to exploration, development and mining. Dave has extensive experience in many deposit types, and especially gold deposits, having worked globally for a variety of clients including both major and junior companies. His focus is on advanced projects and active mining operations, aiding in the interpretation of mine site ore controls and applications of mine geology to local and district scale exploration activities, and training of geological teams. He is an advisor to several companies.

Brett Davis: Firstly, thanks for giving Coring the opportunity to interview you, Dave. Very few people have a career like yours, where you’ve worked across the spheres of academia, mining, and exploration, plus gained enormous respect in the geological community while you’ve been doing it. Can you tell us what interested you in a career in geology?

David Rhys: Thanks for having me, Brett, it’s an honor to be invited to contribute to this column. I grew up in Vancouver, Canada, where the wilderness and mountains begin at the city’s edge. That’s how I was able to see first-hand the effects of geological processes during outdoor trips from a young age. Geology became a career I worked towards early on, especially with the influence of the government geological surveys and the mining industry based in Vancouver at the time.

BD: Coring started as a drilling magazine, and we like to keep to our roots. So, I’ll ask you a drilling-related question. Do you do much work with oriented core? Do you have any horror stories with regard to core orientation?

DR: I frequently contribute to the set-up of data collection protocols and the review of data obtained through oriented core. In disasters, I’ve seen years of client data rendered useless even with good orientation marks from the drillers, due to poorly traced reference lines and inconsistent protocols. The latter principally occurs in inconsistencies in beta orientation collection due to the use of different tools, software, or poor training.

Another ongoing issue I see is that even where the core is well-oriented, there is often insufficient or inconsistent subdivision of structural features, and often collection of irrelevant or biased data. These issues obscure principal structural features. In general, these issues can be aided by training on both outcrops and/or core, and by the use and plotting of the data by the same people who gather the data, which allow geologists to recognize and focus on the most useful and representative features.

Geologists are also sometimes restricted to data collection with only a small number of fixed generic structure codes within the software provided to the site. This limits the effectiveness of the utility of the database. Given the associated costs and efforts of core drilling, orientation efforts and geologists’ time, this is counterproductive and based more on the ease of imposed database design and maintenance than on the reality of finding and interpreting ore deposits. The most effective databases are generally customized to the conditions and geology of the project.

Televiewer technology can work well as an alternative to oriented core under appropriate conditions. However, where imagery is obtainable and of sufficient resolution, it is most effective when the geologist logging the core correlates and tags features in the imagery for measurement, so that relevant data is obtained and not lost in a sea of uncoded data points.

BD: You’ve worked in a lot of countries and on a lot of continents. Are there any skills or mindsets that have helped you in your roles in these places?

DR: Respect and interest in the people one works with, of course, are some of the principal approaches, which bridge cultural, technical and individual divides, and bring people out of their shells to provide them with the confidence to interact, learn, and convey their ideas and observations. Respect breeds respect and enjoyment of the task and downtime with the people one works with are also generally contagious and motivating.

BD: One topic we commonly talk about but rarely put into print is of the health hazards of working in different countries and environments. Has your health ever been particularly challenged and, if so, what happened?

DR: I’ve been fortunate to avoid any dangerous health or major personal safety issues. Usually, if the water supply in an area is good, food safety is generally higher with the regular cautions. In parts of Africa and South America, I’ve found it’s often the cities after the fieldwork where one can pick up ailments more readily since in the countryside food is generally cooked more thoroughly and water is always bottled. Never underestimate the risk of malaria or dengue fever in the tropics because while there are often few mosquitos, a high proportion of them can carry it. Taking or carrying antimalarials and basic exposure prevention is important, even when passing through airports in high-risk areas where watered plants can provide a breeding site for mosquitos. But the greatest health risk is often the drive to the field or the hotel in countries where road safety is an afterthought.

BD: Who have been some of the positive influences in your career?

DR: Just after graduating from undergraduate studies, I traveled through Australia and ultimately ran out of money in Darwin. In those days, there was no internet or email, so I took a stack of coins to a phone booth and called local mining companies, ending up with two offers in the Pine Creek area. Both offers led to the first major mentors in my career, including Greg Partington and Michelle Stokes, who gave me the opportunity to run the exploration of a property package there.

In the early 1990s, the merging of plate tectonics and metallogeny was well underway with and geochronology was providing better constraints on geological cycles and the positions of different styles of deposits within them. After returning to Canada from Australia, I was fortunate to be involved for my MSc in the first MDRU project in the Iskut area of BC. There, James MacDonald, Colin Godwin, John Thompson and Peter Lewis together helped shape my geological approach and understanding, which continues through my colleagues and co-collaborators. Despite being an independent consultant, it is important for me to often work in a team with other professionals who provide ongoing interaction and differing perspectives that continue to positively influence my professional work.

BD: Given the current multi-commodity mineral boom, are you doing a lot of work outside of the commodities and deposit styles you have traditionally worked on?

DR: No major changes yet, although I’ve done work in the past on deposits with metals which are now part of the increasing critical metals focus. As the range of deposits in this broad boom becomes better understood, I’m sure there will be practical structural aspects to define in some of these for both exploration and internal grade understanding even in deposits that don’t have obvious external structural controls.

BD: Is there a particular mineralization style or deposit type that interests you, and why?

DR: In part because of their high degrees of structural control and also with seeing a large number of them, which allows comparisons between the deposits and districts of different ages and regions, gold deposits of different types are my general focus and area of principal interest. Epithermal deposits, which are not significantly eroded, often have synvolcanic histories that may allow evaluation of the whole system scale, including the paleosurface and lithological architecture. This in turn can also influence the position and nature of the deposits. These more than other deposit styles can therefore provide a mineral systems view allowing applications to district exploration, and the opportunity to assess relationships of other associated arc-related deposit types.

BD: Leading on from the previous question – everyone has a handful of deposits that have left a mark on them, be it because of the amazing geology, the hideous conditions, the people they worked with, etc. Which deposits do you hold dear and which ones really were difficult to work on?

DR: The deposit, which was the subject of my MSc thesis, the Snip Mine, encapsulated a wide range of aspects that made for a perfect research topic, including its association with a Cu-Au porphyry system and skarns. This is an unusual occurrence in a ductile shear zone in the thermal aureole of the porphyry which formed at a critical time during the development of the Jurassic arc in BC, and consequently for a very holistic study. It was also a good place to be at the time, on a beautiful camp with great people in a spectacular setting.

In the Abitibi, I was involved during the early development of the Hoyle Pond Mine, and have been regularly going back since the mid-1990s. Following the orebody downward and seeing it evolve as mining continues to nearly 2 km (1.24 mi) depth has been particularly informative.

One of the more challenging projects I’ve recently worked on is the Yanacocha mine in Peru since – in addition to logistical challenges of the work – with more than eight million years of overprinting, telescoped alteration-mineralization events, late faults, and deep supergene alteration in an intense lithocap, the important ore controls are largely obscured.

David Rhys in the field
David Rhys in the field

BD: Do you think that there are any mineral exploration strategies or technologies that are under-employed, but could make a big difference to an exploration campaign if people used them more?

DR: Human brains to help guide, constrain and filter these technologies!

BD: We hear all about the advances and benefits of technologies, such as 3D modelling, geochemical analysis, and utilization of drones. Have you noted any negative impacts to effective exploration and mining as a result of these e.g. less people out kicking rocks?

DR: This is particularly notable in the reduction of surface and open pit geological mapping, and therefore lack of good outcrop maps and interpretations that can form a foundation for exploration and mine ore controls. There is often an incorrect perception that geophysical interpretations and drilling models can replace good maps where outcrop exposure is available, and there is a diminishing number of geologists with mapping experience through retirement attrition and fewer university training programs. As the industry relies on more data, the importance of a good base map that incorporates such field interpretation only increases and forms an essential source for modeling and targeting in many projects. Those who become proficient at geological mapping tend to be some of the best and most observant geologists: good mappers will always be in demand.

BD: Has there been any single satisfying moment in your career that rates above all the others?

DR: In the early 2000s, when conducting ongoing consulting for Placer Dome in Timmins, Greg Hall visited in his capacity as Chief Geologist. Greg involved me in both expanded regional camp scale modeling there and an exchange with the talented Kalgoorlie-based team, as well as technical sessions and mine visits. These highly productive exchanges provided the impetus for further exploration and understanding of ore controls through comparative work between the regions, and lead to many associations with colleagues that I continue to have today.

BD: I’ll ask a question on the flipside to the previous one. Many of us have interfaced with less-than-savory individuals or experienced toxic workplaces. Has there been any incident or incidents that really disappointed you?

DR: Early in my career especially, during work for a minority of junior clients, I’ve been exposed to some questionable promotional tactics, and in one case suspicious activity, which ultimately proved to be fraudulent. In the latter case, the lack of correlation between assays, assay intervals and geology in one project I worked on was sufficiently concerning to seek legal advice, although there was no clear proof of fraud at that stage.  After a couple of consultants subsequently provided reports on the project which appeared to validate the company data, my concerns diminished. However, a third group later determined that assays had been indeed manipulated and the single perpetrator in the company was ultimately found guilty. My initial report, which documented the inconsistencies I observed, was used in the legal proceedings.

In retrospect, I’m sure that my requested presence at the site was to provide credibility and cover without anticipating that I’d complete as much review as I could. I’d hope that under the current regulatory regime and higher expectations for QA/QC that this may not have occurred or could have been detected earlier.

BD: You are one of the rare breeds of geologists who work in the industry but manage to maintain a publishing career. What inspires you to publish and how do you overcome the challenges, such as finding the time?

DR: While it’s a bit of an arduous task at times, especially during the writing and editing process, publishing is ultimately quite satisfying. It takes the consulting work to a higher technical standard that involves further research and learning and allows the dissemination of otherwise invisible internal work to the broader geoscience community. As many of my projects are long-term and advanced, there is the opportunity to develop concepts and make for substantive contributions. I’ll often set aside a month or two a year for this process, which benefits from already having a base for the papers from what has been written and illustrated in my consulting reports. Ultimately, the papers, as well as short courses I’ve given that benefit from reference to the published material, make up for the voluntary time and elevate my profile, leading to more new work opportunities and added value and demand from my long-term clients.

BD: Are you undertaking any active research now?

DR: I’m fairly steady on that front working towards a series of papers as time and field projects continue. While also doing work for clients in areas of research interest, I’ll often set aside some personal time to conduct traverses and visit adjacent mines to place the deposits or districts into a better context. As my wife does petrographic work, we can also address the paragenetic, textural and microstructural aspects on most of our projects. She has connections with the local university for more rigorous analytical and geochronological work, together contributing to the research aspects.

With these approaches, I’m currently continuing work on the understanding of the structural controls and setting of the Carlin gold deposits in Nevada, USA, and finishing up a major multidisciplinary review of the Fosterville deposit with the mine team that will lead to a paper addressing its deposit structure and vein evolutionary history. I am also working on papers based on my many years of ongoing work in the Timmins area and other deposits in the Abitibi Belt. I have planned a collaboration to provide review papers on the structure of orogenic gold deposits with Stephen Cox, and orogenic gold diversity with Rich Goldfarb. We will continue to flesh out both papers during an upcoming SEG short course in London. While these projects may seem quite ambitious, I treat them as multi-year objectives which I work toward as time permits.

David Rhys in the %eld
David Rhys in the field

BD: Do you think that geological societies, such as the Society of Economic Geology (SEG), have adapted to the times in terms of being useful entities for their members? Or are there basic things that such societies should be providing and/or promoting?

DR: The SEG and other societies are doing their best to adapt to changing commodity demands, technologies, demographics and social concerns, as it is illustrated by many of the themes in the upcoming conference in London. But while there is a paid staff at the larger societies that run the business and administration and oversee the editorial aspects of their publications, the technical and educational offerings are determined and provided by volunteers and the financial support of the fees and company contributions. These societies are therefore dependent on the time we in the industry, who have technical, educational and/or management skills, are willing to provide to make them successful and relevant. So, as a community, I’d encourage your readers with the time and skills to offer to give back to these societies. This could be through volunteering, presentation of courses, by publishing scientific contributions, or by participation in community outreach.

Participation could also be by simply attending conferences and courses provided by the societies, to be part of the overall community and exchange of ideas, as well as through the fees generated from these events and membership which provide funds for the societies to function. As we are facing a diminishing pool of young geologists, and a need to train international geologists within their home countries, educational outreach is also becoming increasingly important to support the industry. Education can only be provided by those of us who volunteer our time or participate.

BD: Finally, any concluding comments or words of wisdom from an industry veteran?

DR: For early career geoscientists, I’d encourage obtaining as much field experience as possible, even if it means some sacrificed time away from family and friends. Regardless of the ultimate path you may follow in the industry, this initial base can give you the diverse experience and context to draw from in the future, as well as the immersion in the culture and camaraderie of a worksite or project. Try to practice and encourage critical thinking, observation and good evidence-based interpretation in your work, especially with the introduction of so many new technologies. You were trained to be a geologist, not a technician. This is often one of the more satisfying parts of the job.

For more information get in touch with David Rhys on LinkedIn