Consistency and Accuracy when Describing Geological Structures and Rock Fabrics

Graham Banks, Senior Principal Geologist, WSP Canada.

Sarah Cox, Senior Geotechnical Consultant, WSP USA.

Steve Rogers, Senior Principal Geoscientist WSP Canada.

Luca Zorzi, Principal Geologist, WSP Canada.

Scot Foster, Senior Vice President, Global Mining Client Program, WSP Global Inc. (USA).

Geologists and engineers on mineral exploration and mining projects often assign different words or modes of rock deformation to the same rock feature. The consequences of this variety can be significant for evaluating the stability of a mine. By implementing rigorous guidelines and accurate vocabulary, the mining industry can mitigate the risks and failures caused by these inconsistencies, and deliver more reliable interpretations.

If you are a geologist, geotechnical engineer or rock mechanics specialist, test yourself with the questions below and compare your answers with your colleague’s:

·???????What’s the difference between a fracture, a joint and a discontinuity?

·???????Is an infilled joint a vein?

·???????Is a fault a portion of a rubble zone or vice versa??

·???????What are the criteria scientists use when they distinguish “Fault” from “Shear zone”?

·???????Why do people categorize a rock fracture as “healed” when broken rocks cannot self-repair or alleviate stressful emotions?

·???????How big and influential is a “major” or “primary” fault for a mine’s stability?

·???????Which of the many structural data gathering guidelines is rigorous enough?

Would you label the curviplanar structures as fractures, joints, faults, shears, veins or discontinuities?

Accurate terminology and description of rock mass structures and fabrics is crucial to the mining industry due to the unique and distinctive challenges that demand collaboration across multiple practice areas.?Clear communication of rock mass structures and fabrics is essential for: rock mass characterization, mine stability predictions, structural geology models, mineral resource estimates, geotechnical assessments, hydrogeology studies and geohazard analyses. A shared, correct vocabulary is also crucial to communicate the implications of rock features to mining economists, risk analysts and investors.

Would you categorise these geological structures as joints, fractures or discontinuities?

Unfortunately, the terminology and methods used to describe geological and human-induced rock structures often lack consistency. Even seemingly straightforward terms like "fracture" have become misused and confusing. Some geological dictionaries and textbooks are also inconsistent, or their definitions are not appropriate for industry applications. This variety creates biases, uncertainties, doubts, disagreements, and even project failures. Using our preferred words reduces our ability to objectively describe and compare rock mass features. Yet, this variety and incoherence is unnecessary, for example a rock joint has characteristics that clearly distinguish it from a fault and a tension gash.

To address this issue, the mining community would benefit from a standardized document that accurately defines vocabulary and techniques for describing rock structures and fabrics. Industries such as healthcare, aviation, and petroleum geology rely on precise and consistent language usage across organizations. It's time for the mining industry to have the same. Mining geoscientists and engineers can then be as consistent with deformed rock vocabulary as doctors and airline pilots are with their technical vocabulary.

At WSP Mining, we are taking the lead and compiling an up-to-date glossary of rock fabrics, geological structures and their networks. These definitions are derived from peer-reviewed glossaries created by scientists known for their accuracy and rigour. The glossary also contains a recommended sequence to observe, describe and then model rock mass fabrics and structures. Let's enable consistency and accuracy in mining vocabulary and techniques when describing rock mass structures and fabrics. Together, we can improve communication, reduce uncertainties, and ultimately increase the chance of success in mining projects.

Reach out to us if you’d like to know or discuss more.

#structuralgeology #geotechnicalengineering #rockmechanics #exploration #mining #WSPMining