The month-long pilots involved haul truck drivers who did day and night shifts. Among the key findings were that day-shift workers hit their highest level of fatigue on the last day of their work week. Night-shift workers, however, experienced high levels of fatigue as early as their second work day through to the last day of their work week.
"Fatigue is a term used to describe a wide variety of conditions," explained Justin Tueller, industrial hygiene specialist at Cortez. "We summarise it as the feeling of being tired or weary because of insufficient sleep, lengthy periods of mental or physical work, or prolonged episodes of stress or anxiety."
Cortez identified fatigue as a key risk to worker safety and said the pilot projects are a proactive way to address the issue. A person struggling with fatigue will show slower reaction time, make more errors and experience decreased cognitive ability. The type of shift, number of breaks, consecutive shifts and hours worked per shift influence the risk level in the workplace.
One of the projects, the Predictive Safety pilot, involved short two-minute tests on tablets conducted before and after shifts at the Cortez open pit. Each shift, 20-25 participants filled out a sleep questionnaire and took an ‘alert monitoring' test, which calculated reaction time based on how quickly participants completed the questionnaire. The results were entered into an algorithm that produced each employee's fatigue level. There were three levels: guarded (low fatigue), significant or high.
The second project called Smartcap used Bluetooth technology to connect haul truck systems to specialised headbands worn by operators. The headbands monitored the fatigue levels of 20-25 open-pit operators per shift by taking electroencephalography (EEG) readings.
The device, which fit into a standard hard hat or cap, is similar to an echocardiogram (EKG), but it monitors electricity emitted from the forehead rather than the heart. The EEG results appeared on a monitor mounted inside the cab of the open-pit haul trucks every 2-3 minutes. Drivers experiencing high levels of fatigue would be notified by alerts from the system. If a driver received three high-fatigue alerts without taking a break, the system would flag this for a supervisor who could then intervene and assess a driver's fitness for duty.
According to Barrick, the projects helped employees self-manage their fatigue and determine when they may experience a fatigue ‘wall'. Seeing the results and acknowledging how their fatigue progressed throughout their shifts helped employees identify the most opportune time to counter fatigue by drinking a glass of water or taking a quick walk.
"Many participants have acknowledged an increased awareness when it comes to their personal fatigue management," Tueller said. "This awareness will help minimise fatigue-related incidents."
Cortez is evaluating data from the projects and determining whether to proceed to a site-wide implementation. This would see the Smartcap system expanded to more equipment such as loaders and graders, and the use of the Predictive Safety testing tool in other divisions, such as the Cortez Underground. The tool may also be adopted at the Goldstrike mine.
