The psychology of slope stability radar use: What operators need to know

Slope stability radars have progressed to become integral, valuable and widely used pieces of diagnostic, decision-making equipment across mine sites. While expertise in technical application is essential, geotechnical engineers must also look beyond to consider the psychology around their use – from the perspective of all mine site stakeholders – to ensure safety of themselves and the operators on the ground.

Cartledge Mining and Geotechnics Director, Tim Cartledge, explains.

It’s often said, you don’t know what you don’t know. But in geotechnical engineering, deep knowledge builds safer working conditions so it should always be our mission to keep all stakeholders informed.

When it comes to the use of slope stability radars on mine sites, as geotechnical engineers we are well versed in the critical equipment’s capabilities in strategic and tactical monitoring and decision-making around safety. We also understand the powerful tool’s limitations – knowledge others working in the field may not necessarily have.

To enhance our risk-informed decision making, and ultimately the safety of everyone affected by these decisions, we need to extend our understanding of potential knowledge shortfalls across other site personnel. People’s lives are in our hands, and we must effectively communicate radar findings, plans and any remaining risk to people when in the field, even with radars in use.

Understanding the psychology

Radars have become almost second nature across maintaining and determining safe operations, and increasing productivity.

Nowadays, much trust is placed in radars’ use, and rightly so, because they enhance our confidence to work in certain environments and get people in and out safely.

It is the operators and supervisors on the ground, whose lives are at the greatest risk. When mine workers see a radar on site, a common assumption is, “We’ve got a radar there. It’s monitoring everything and we’re safe. If anything goes wrong, it will alert and alarm us, and we’ll have lots of time to get in and out, when the wall moves.”

While this can be true, people tend to feel safer and more protected than they should because of a lack of knowledge.

Just another hard hat?

Elimination, substitution, isolation, engineering, administration, PPE ... when you break it down, the radar is simply personal protective equipment (PPE). In terms of the hierarchy of hazard controls, this means it sits at the bottom of the triangle, the least effective tool. When working in the field, operators are not necessarily paying attention to the wall to decipher, “Are there signs of movement? Are there things we’ve got to be looking for?” The assumption is, because the radar is there, “it’s going to tell us everything”, but that’s not entirely the case.

Operators and supervisors don’t necessarily know the nuanced limitations around line of sight, for example, that unless a radar is perpendicular to the direction of movement, it is unable to measure true movement and true deformation. Or if a wall moves too quickly, it won’t measure accurately. Or, if there is too much activity in front of a wall – an excavator in front of a small bench, for instance – the radar cannot detect movement.

As geotechnical engineers, data and knowledge underpin all we do, and we don’t assume without evidence. Likewise, it would be unwise to automatically expect operators to understand these limitations, and others, including:

• Scan time sequencing (phase ambiguity)

• Atmospheric artefacts

• Alarm thresholds

• Rockfall detection

The two-part solution

The ‘human factor’ is an ever-present reality, so a key part of our role and responsibility is to continue to train and communicate, using the tools at our disposal.

With training, it is vital to inform production personnel on how the radars operate, what they’re doing and what they’re capturing.

With communication, especially around the more strategic, long-term monitoring, this can be a weekly update, detailing what is being measured, an update on monitoring, movement, and current plans of action.

When work is under way on a wall, the approach becomes more tactical. Then, it is vital to inform operators and supervisors daily so they can report to their teams about what the tactical monitoring system is doing, and what they should be aware of.

It may take extra time and effort, but this is critical to safety, as well as meeting production goals.

Building trust: Why getting it right is vital

Because radars have become so heavily integrated into the systems and processes, in some coal mines, for example, mining is not allowed without a radar operating and monitoring a wall where work is under way.

So, if the radar goes down due to communication issues or malfunction, runs out of fuel, or myriad other issues, then mining can grind to a halt. That can cost a few million dollars a day in lost productivity.

If there’s a failure developing, we need to ensure the radar identifies that failure, triggers the way it’s supposed to and the equipment and personnel can get out of the way, the way they are supposed to.

Getting it right takes diligence, time and persistence. But when lives are in our hands, there must be no shortcuts.