Between a rock and a well-informed place

Advancing technology is elevating the industry’s systematic approach to rock wall analysis.

The topography and materials of mine sites can vary greatly in complexity and mines are bigger nowadays, with faster production than ever. This means the pace of design and geotechnical engineering work must accelerate to keep up. In this article, Cartledge Mining and Geotechnics Associate Geotechnical Engineer Tom Lynch explores the steps to conducting crucial rock wall analysis and how ever-advancing technology is changing the face of this critical work, with safety at the core of it all.

Mining in Australia operates on a larger scale and at a much faster pace than ever before. This demands a rapid speed from all stakeholders to power production and meet targets.

Improved safety is the impetus for geotechnical engineers to keep up and rapidly advancing technology is optimising our crucial rock wall analysis, advice and ultimately the safety of personnel on the ground across a mine site.

Working faster should never be at the risk of quality and attention to detail, however, and by following a rules-based approach, armed with the right tools, a geotechnical engineer’s complex task of analysing material and wall strengths, modelling and providing recommendations to mines can become better-informed, and executed more efficiency and accurately.

Crucial steps: Assessment, modelling, reporting, recommendations

Stability assessments underpin all safe site work and are a crucial first step in rock wall analysis.

Reviewing proposed or existing walls should always capture the geometry – the foundation materials, wall profile, geotechnical strata materials, sheer strength and parameters of it all – in analysis software. Often the material parameters are already known, in other cases we may have to derive them from site investigation and lab test results.

Depending on the complexity and size of a wall, this assessment produces a 2D or 3D model, which then provides a factor of safety.

Knowing the forces at play and meeting required factors of safety – either 1.2 for active mining conditions, or 1.5 for long-term stability – is pivotal to the ability to model and ultimately, safely mine an area.

For a mine’s technical services division and engineers to be able to get to work, they rely on our reports and recommendations that this modelling produces.

When all results meet the factor of safety, and no real recommendations are needed, work can begin or continue. When the factor of safety isn’t achieved, our recommendations guide how to improve or change the design to meet mining targets.

Challenges to climb

As with most data-driven work, the result is only as reliable as the initial input. It’s therefore critical that the information obtained from the source is as well-grounded and complete as possible.

It’s often a fluid process, with data updates ongoing, so it’s important to be agile in response and re-modelling throughout, to ensure safety, always.

This is often steeped in complexity, as we found in our work in Papua New Guinea at a complex mine site, with difficult topography. Ultimately, obtaining accurate data enabled us to accurately model, using 3D software, to provide best-practice recommendations and ensure the safest approach as the mine’s initial personnel engaged in site setup.

At any one time, a single geotechnical engineer could be working on half a dozen or more rock wall analyses – so it’s important we uphold communication with all stakeholders, manage expectations on delivery and any extenuating circumstances.

Technology driving service delivery

Through working faster and harder, as the industry demands, we must also work smarter – which is where the latest technology comes in.

Delivering recommendations with confidence hinges on accurate modelling and software advancements are powering our abilities.

While CAD programs are not new in the industry, they are constantly improving and developing.

And as computer hardware improves, the ability to run more RAM-intensive and graphics card-intensive software also rises, allowing us to produce more detailed, more advanced analysis faster.

Up to five years ago, a laptop wasn’t capable of running more complex 3D software, which now can be run on the portable PCs, opening up the ability to work from any location and enhancing speed to delivery.

Where to from here?

As technology advances, and pressures on our already under-resourced sector continue, the reliance on 3D modelling will increase.

While nowadays we run 2D as standard, we will find in the not-too-distant future, enhanced computing power will shift the ‘norm’ to 3D modelling, simply because we can.

As this modelling becomes more complicated, the focus on geotechnical data acquisition must become sharper, and it is only through a strategic approach, including clear and focused data entry, analysis, and robust recommendations, that we will be able to meet rising needs and ensure safety across mine sites.