Canadian Mining Journal


SIX Safety Systems outlines how mining companies can manage fatigue-related risks

Being awake is not enough

Imagine this…

One of your top haul operators, John, is rubbing his eyes, yawning and moving slowly. You know that John still has 4 more hours on shift.

You ask him how he is and he responds, “I’m fine, just a little tired”.

What do you do? Do you get him a cup of coffee? Do you make him take a break? Or, do you tell John to “just be safe out there”? What actual written procedures do you have in place? I’ve posed this question to senior managers, supervisors, and safety personnel hundreds of times, and more often than not, I’m met with stony silence.

You may think, well, it depends on his job. A valid point, but only if you’ve assessed the job to determine how fatigue can impair work performance.

Fatigue is not simply being tired. It is not about being lazy, and it is certainly not about just keeping your eyes open. At some point, we have to start looking at the flaws in the system, and not just the flaws in behaviour.

Safety professionals recognize that the most important question in their arsenal is to simply ask, “why”? Why are they tired? Didn’t get enough sleep? Why? Put in overtime? Why? Because the crew was shorthanded? Why? You get my point.

Workplace fatigue factors

The science is clear. Workplaces need to understand their role in the promotion and mitigation of fatigue. While there will always be personal reasons as to why an individual may be struggling to stay awake, there are three primary fatigue influences that organizations have some control over.


Simply put, the longer it’s been since your last sleep period, the more sleep pressure builds due to the accumulation of adenosine in the brain, a depressant. After being awake for 14 hours, sleepiness starts to set in. At 17 hours, you are the equivalent of .05 blood alcohol impairment (BAC). At 18 hours, you will be struggling to stay awake. At 20 hours, you are equivalent to .08 BAC, and your cognitive abilities drop by up to 40%.

What level of risk is tolerable for your organization? How does your schedule stand up?

Circadian rhythms

Every body function and organ has its own body clock based on the 24-hour rotation of the planet. These clocks tell us when to be awake, when to sleep, when certain hormones should be released, when our body can best digest food, etc. The maestro controlling everything is our “master clock” in the brain. It’s controlled by the amount of light entering our eyes, even when they are shut. This master clock is what all the other clocks try to synchronize with.

Based on our circadian rhythms, humans are a day-oriented (diurnal) species. This means we will always perform better and be more alert and safe when working during daylight hours and get our best sleep during dark night time hours. We are at our worst between midnight and 6 a.m. when we are programmed for sleep. There is also a dip in our rhythms in the early afternoon (the siesta period), which can also affect alertness and performance.

Task demands

The more demanding our work tasks, the more fatigue accumulates.

From a cognitive perspective, it has been demonstrated that mental tasks longer than 30 minutes deteriorate if tasks are monotonous or tedious. This means sustained vigilance tasks such as operating machinery or more commonly, the commute home after work, is when we are often in jeopardy for something to go wrong.

Fatigue impairs our ability to perform. How do these impairments affect the safety of your mining operations?

  • Loss of situational awareness
  • More time on task
  • Under-estimation of risk and more of a “it’s good enough” attitude
  • Flawed logic
  • Hindered visual perceptions
  • Slowed information processing
  • Reduced reaction time

Fatigue incident trajectory

The mining sector has been a world leader in the utilization of fatigue detection and monitoring technology, and in many cases, with much success at identifying fatigue before it hits a critical point. But such technology is not a solution in and of itself. In essence, technology does not ask why fatigue is occurring in the first place.

Fortunately, a lot of smart people have been asking why, and it has led to an understanding of how a fatigue related incident develops.

Level 1 Assessment – Sleep opportunity

It doesn’t matter what John does if the schedule he works does not allow him enough time for recuperative sleep in addition to his commuting and meal times. Science has recognized that all adults require between somewhere between 7 and 9 hours of sleep to physically and mentally recuperate every 24 hours.

What can you do?

  • Review work hours including extra-work, on-call, and overtime assignments;
  • Perform a workload analysis; and
  • Review commuting and travel management factors.

Many industries and regulators have viewed fatigue as a linear function based on a result of total hours of work/rest within a schedule and ignoring how complex it really is. One of the tools SIX Safety uses is FAID biomathematical modelling software to evaluate work schedules for fatigue related risk.

Initially developed specifically for the mining sector, it allows us to evaluate the start and end of work assignments, duration of work and breaks, previous work history, and of course, circadian factors. While it can be used to declare whether a schedule complies or not with prescriptive hours or recommended standards, a better approach is to use it to identify at what point in the schedule risks for errors or incidents climb to intolerable levels. Then, we can work with the company to determine the best ways to mitigate that risk within the schedule.

Level 2 Assessment – Sleep obtained

The next step in the incident trajectory is to evaluate whether or not the employees are capable of getting the sleep they require. This can be achieved in a variety of ways.

  • Worker survey
  • physiological monitoring (actigraphy)
  • Sleep disorder screening
  • Evaluation of task lighting Light exposure needs to be optimized to both increase alertness while not eliminating the production of melatonin, out body’s natural sleep hormone which helps fall asleep and stay asleep. There are a variety of lighting strategies that exist.

Level 3 Assessment – Fatigue related behaviours

Remember tired John? How many of your supervisors have been trained in how to identify an at-risk worker? How do you want them to react? Consider the following.

  • Training workers in sleep hygiene and shift work lifestyles;
  • Training Supervisors in identifying and intervening with fatigue;
  • Onsite rest/recovery options; and
  • Detection/monitoring technologies.

Here at SIX Safety Systems, we utilize our LUCI Eye Gaze technology designed to provide feedback first to the worker if they cross a threshold so they can take action. If their risk level continues to increase, then notice is given to a supervisor or dispatcher so they may intervene. The aggregate data can then provide guidance to ensure informed decision-making.

Level 4 Assessment – Fatigue related errors

If you have weaknesses in the first three levels, errors will result.

Now what? It’s time to evaluate what procedures you have in place both when an error occurs, and before it occurs.

  • Completion of cognitive analysis of work tasks;
  • Review of shift handover protocols and communication structures; and
  • Implementation of an error analysis system that includes fatigue.

Level 5 Assessment – Fatigue related incidents

Not all incidents are the result of fatigue, but it could be a contributing factor. Now is the time to redesign your investigation protocols by incorporating:

  • Fatigue Investigation Checklists (post incident); and
  • Performance Impairment Checklists.

In the end, it’s about understanding where your fatigue related risks are, and not relying on workers to simply show up with their eyes open. Being awake is not enough!

MIKE HARNETT is the vice-president of human factors for SIX Safety Systems, a consulting firm that specializes in fatigue management solutions. He can be reached at mharnett@

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