Geotechnical Engineering or Geomechanics?
Part II: Putting This Dilemma to Rest

Several years ago, I wrote an article asking why the term geotechnical engineering is used in mining.

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At the time, I concluded that geotechnics and geomechanics could largely be treated as interchangeable terms in a mining context. 

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I would refine that conclusion today.

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The two terms describe closely related areas of work, and different companies, countries and professional communities use them differently. There is no single naming convention across the mining industry.

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However, there is a distinction.

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Geomechanics is concerned with how the ground behaves as mining progresses.

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This includes the behaviour of rock and soil, the influence of geological structures and groundwater, and the response of the ground to excavation. This broad interpretation is consistent with the Australian Geomechanics Society, which defines geomechanics around the behaviour of ground and groundwater and its application in civil, mining, offshore and environmental engineering.[1] 

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In mining, geomechanics therefore deals with questions such as:

• How will the ground respond when material is excavated?

• How will stresses and deformation change as mining progresses?

• Where might instability or failure occur?

• How do geological structures, material properties and groundwater influence that behaviour?

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These questions are relevant to open pits, underground mines, waste dumps, tailings facilities and other mining-related structures.

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Geotechnical engineering applies this understanding to the investigation, design, monitoring and management of mining excavations and related facilities.

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This is close to the way AusIMM defines the professional discipline. Its current Chartered Professional framework states that a Geotechnical (Mining) professional investigates, plans, designs and monitors mining excavations and associated facilities. The listed areas of practice include site characterisation, geological structures, rock properties, rock and soil conditions, water, analytical and numerical methods, ground control, monitoring and risk management.[2] 

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In practical terms, geotechnical engineering deals with questions such as:

• How steep can a pit slope be?

• How large can an underground excavation or stope be?

• What ground support is required?

• Where can mine infrastructure be located?

• What monitoring is needed?

• What conditions should trigger action?

• How should geotechnical uncertainty be reflected in mine planning and operations?

 

The distinction is therefore straightforward:

     > Geomechanics helps us understand ground behaviour.

     > Geotechnical engineering uses that understanding to support engineering decisions.

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The boundary between the two is not rigid.

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A mining geomechanics specialist may perform much of the same work as someone called a geotechnical engineer. Other operations may use titles such as rock engineer, ground-control engineer or strata-control engineer.

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This is why job titles vary considerably across commodities, jurisdictions and companies. But the work itself is easier to understand than the terminology.

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A modern mining geotechnical function may bring together:

• geological and structural interpretation

• rock-mass and soil characterization

• hydrogeology

• geomechanical analysis

• numerical modelling

• slope and excavation design

• ground-support design

• monitoring

• geotechnical risk management

• mine-planning input

• review of actual ground performance

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Geomechanics is an essential part of this work, but it is not the whole of it.

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This is why I prefer geotechnical engineering when referring to the overall mining engineering function. The term covers more than analysis of how the ground behaves. It includes the process of turning geological and geomechanical understanding into designs, controls and operating decisions. 

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This becomes particularly clear when geotechnical engineers work with other mining functions.

A mine planner does not only need to know how the ground may deform. The planner needs to know what that means for slope geometry, mine access, sequencing, reserves and schedule.

Operations do not only need a prediction of ground response. They need practical operating limits, monitoring requirements and clear actions when conditions change.

Project teams need to understand how geotechnical conditions affect mine layouts, infrastructure and development choices.

Management needs to understand the uncertainty, the potential consequences and the available options before major decisions are made.

This is where geotechnical engineering connects ground behaviour with the wider mining system.

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The terminology used by professional organizations illustrates why the distinction can appear confusing.

AusIMM established its Geomechanics Society in 2025 specifically to support the growing community of geotechnical engineers working in mining and resources. Its scope includes open pit and underground mining, tailings, rock mechanics, soil mechanics, slope stability and ground support.[3] 

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This is not a contradiction. It reflects how the terms overlap in practice.

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The distinction between mechanics and its engineering application also has a useful precedent in rock engineering. In 2017, the International Society for Rock Mechanics added “and Rock Engineering” to its name. The Society explained that the change reflected its involvement not only in the theoretical and academic aspects of rock mechanics, but also in their practical application in engineering. [4] 

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For mining, a similar working distinction is useful:

   > Geomechanics describes the field concerned with ground behaviour.

   > Geotechnical engineering describes the engineering practice that applies this knowledge to real mining problems.

The terminology will continue to vary across commodities and countries, and substantial overlap will always exist. That is not a problem.

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The more important question is whether the function is doing what the mine needs: understanding the ground well enough to support safe, practical and economically sound decisions.

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For that broader function, geotechnical engineering remains the clearest term.

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References:

[1] Australian Geomechanics Society. About Us. Definition and scope of geomechanics as the application of engineering and geological principles to ground and groundwater behaviour. 

[2] AusIMM. Chartered Professional Regulations and Guidelines — Geotechnical (Mining). Current competency framework defining the scope and areas of practice of a mining geotechnical professional. 

[3] AusIMM. 2025. Welcome to the AusIMM Geomechanics Society. Description of the Society, its purpose and technical scope. 

[4] International Society for Rock Mechanics and Rock Engineering. 2017. ISRM Name Change — International Society for Rock Mechanics and Rock Engineering. Explanation of the distinction between rock mechanics and its practical engineering applications.