Structural Geology—a forgotten discipline in mineral exploration

The link below is to a video of a talk by Orefind structural geologists Brett Davis and me—Jun Cowan. This talk was given on the 21st of May, 2018, at the Australian Resources Research Centre, Perth, for the Applied Multi-scale Structural Analysis in Mineral Exploration Workshop organised by TeamWA and Geoconferences, and sponsored by Orexplore. We thank Brendan Hardwick and the organisers at TeamWA and Geoconferences for the invitation to give a talk at this workshop. 

At this workshop, these speakers gave talks but only ours was recorded:

• Fariba Kohanpour (University of Western Australia) on her PhD research on the structural control of gold and nickel deposits of the east Kimberley.
• Sarah Jones (Gold Fields) on the deformation and mineralisation history of the Agnew District.
• Russell McChesney (Orexplore) on ‘GeoCore X10’—a new 3D core x-ray scanning technology from Sweden.
• Stanislav Ulrich (AngloGold Ashanti) on structural permeability and fluid pathways in orogenic gold deposits.
• Jun Cowan and Brett Davis (Orefind) on Structural Geology—a forgotten discipline in mineral exploration.

More than 100 people—mostly young working geologists—attended the talks. After our talk, Brett and I ran an afternoon workshop (attended by 22 people) on how to interpret structural architecture from drilling assay data. 

A casual talk with a very serious message

It’s difficult to focus on a full day of jargon-filled technical talks, so in our hour-long talk we tried to minimise this as much as possible and have some fun—we didn’t want it to be so technical that you miss our important message about structural geology. We want you understand what we are getting at.

Just from a few seconds into the video, you’ll realise that our talk is not overly technical, so regardless of your level of experience in structural geology, you should have no problems following it. However, although our presentation is casual, our talk is about a serious topic and one we’re both passionate about—the decline of applied structural geology in the mineral exploration and mining industry.

Structural geology is effectively a forgotten discipline in the mining exploration industry in 2018. Since I had graduated from university in the 1980s, there’s been a rapid decline in university-level field geology courses, and we’ve seen a corresponding staggering decline in the basic knowledge of structural geology in the industry. This lack of knowledge is affecting the way we explore for mineral deposits.

I was discussing this issue with a structural geology professor at a leading Australian university, who is close to retirement. He was lamenting that his department had recently stopped offering the traditional fieldwork course at the end of first year; this field work is where the basic principles of structural geology are taught. Why? Because the recently hired young academic geological staff were not confident with field work, so they could not assist undergraduates. The university had no choice but to discontinue the course.

My first thought when I heard this was “What the …??!”

We are now seeing young graduates, who have no field experience, yet are potential future professors of geology who may eventually end up advising the mining industry. If this trend continues, university-level field courses will not be taught and will disappear completely, and with them, the practical skills of structural geology. This is a tragedy for the profession. We believe that structural geology is the cornerstone geological subdiscipline that has a major impact on mineral exploration success. If young geologists cannot conduct structural geological investigations, then the mineral industry will suffer as a consequence, and no amount of machine learning algorithms on drilling data will allow us to recover from this decline in knowledge. We will be looking into the abyss of total ignorance.

In this talk, I open by asking why this severe decline in field emphasis and structural geology has occurred. Because this decline has been happening since the 1960s, every geologist currently working in the industry has been taught during this period of gradual decline in structural knowledge. I also point out that this world-wide ignorance has spawned pseudo-structural geological concepts, which are readily accepted without question by working geologists, academics, and academic journal editors. Although these pseudo-scientific concepts can be easily proved incorrect, they are propagated as factual because of the decline in basic structural knowledge. I discuss some of these concepts in my segment of the talk.

One major result of this ignorance is the overreliance by geologists in using published mineral deposit models developed by academics, who are inexperienced at examining mineral deposits sampled by drilling. Many ore deposit models are completely conceptual in nature, with no physical basis that can be readily demonstrated either in the field or by analysing drilling data. This makes them ineffective exploration tools, yet ore deposit models are often accepted as fact, resulting in a blindness in the exploration approach. We illustrate this point by summarising what we found at a well-known VMS deposit in Kazakhstan, which is not an isolated case that we’ve come across in our years of consulting work. Again, this is an unfortunate consequence of industry-wide ignorance of structural geology. We believe we’re not just looking into the abyss of total ignorance, but, as an industry, we appear to be well inside the abyss.

Since the 1960s, the ignorance of structural geology has resulted in geologists not knowing how to interpret mineralisation geometries from their own drilling data. In the talk, I show some fundamental deposit-scale mineralisation patterns, which clearly point to structural controls that can be seen in grade data sampled from drilling. These patterns and their structural controls are simply unrecognised by the geologists at most sites we’ve visited. Brett then discusses the importance of integrating structural geological observations into all other geological observations so as to fully apply structural analysis to mineral exploration at all scales.

I hope you enjoy our talk. Constructive feedback is always appreciated and we welcome considered discussion.

Acknowledgements:

We thank Dr Mirek Benes, Executive Director Exploration of Kazzinc (Glencore company), for allowing Orefind to mention our observations and findings from the Maleev massive sulphide deposit in this presentation.

Many thanks to my LinkedIn connection Stephen Munro to introducing me to Google Book’s Ngram Viewer search tool which is featured in our talk. I’ve found Ngram to be endlessly entertaining and informative!