Heat stress is a serious occupational health problem across mining – and with climate change increasing the regularity of hot weather events, is only becoming more and more of an issue. Andrea Valentino chats with Glen Kenny of the University of Ottawa, and Kristin Yeoman of the National Institute for Occupational Safety and Health (NIOSH), to learn more about the challenges the mining industry faces over protecting workers from rising temperatures, how the so-called ‘buddy system’ might prove more successful than mere rules – and why climate change means the problem of heat stress is only going to continue.
Heat stress is a serious occupational health problem across mining. (Credit: 652234 from Pixabay)
When Paul Fogarty started his day on 14 October 2017, he probably didn’t expect it to be his last. All he and his two colleagues were expected to do was go on a walk – and as a senior field technician, aged just 49, Fogarty was probably confident he could manage the exploration reconnaissance required of him. But, as he began his trek, through the red and dusty outback of Pilbara, things quickly went wrong. The distance was bad enough. A 16km hike is tough at the best of times, let alone over rugged terrain across the thinly populated wastelands of Western Australia (WA). But what really doomed the Rio Tinto employee was the temperature, peaking at 37°C even in early autumn. Perhaps exacerbated by leg cramps from the previous evening, Fogarty soon collapsed, and couldn’t be resuscitated.
After the event, Rio Tinto was forced to pay an A$80,000 fine, as well as costs of A$7,500, for failing to protect their employee – a situation apparently exacerbated by the fact that Fogarty and his colleagues weren’t aware that they had to complete heat stress assessments before setting out that fateful October day. But what’s really remarkable about Fogarty’s tragedy is how common it is. In 2015, for instance, Adam Perttula, another miner in WA, died during a night shift underground, likely due to heatstroke and exhaustion. Two years later, yet another Australian mine worker suffered a similar fate, succumbing to a cocktail of overheating and diesel fumes. Not that the Land Down Under is unique here. According to work by the Mine Safety and Health Administration (MSHA), 150 US miners suffered from ‘nonfatal heat-related illnesses’ in 2014 alone.
In a grim way, the toll is unsurprising. Both due to the regions where mining often occurs – hot, arid places like Australia and South Africa – and the specific conditions of mining as an industry – underground and physically demanding – ensuring miners stay cool has been an industry focus for decades. How you actually manage it, however, is another challenge entirely. For if technology, in the form of cooling and refrigeration systems, can certainly help keep workers safe underground, it hardly helps people like Fogarty. No wonder, then, that keeping miners genuinely secure means much more than staring at the thermometer, instead requiring careful teamwork, strict work policies – and even an understanding of a person’s specific health vulnerabilities.
Cool it
It’s hard to overstate how hot mines can get. Temperatures of 38°C are not uncommon, even as indicators can sometimes soar to over 50°C. And if Fogarty succumbed largely thanks to an Australian heatwave, dangers also lurk elsewhere. As Kristin Yeoman explains, that’s true even if the conditions “might not be considered excessively hot” – for instance, depending on the wind speed, or the location of the sun, or even if an individual is standing near an active piece of machinery. “Additionally,” continues the medical officer in the Spokane Mining Research Division of the National Institute for Occupational Safety and Health (NIOSH), “the metabolic heat generated by mineworkers conducting work tasks of varying physical intensities, as well as clothing and personal protective equipment, will add to their heat load.”
In theory, sweating is the way the body copes with such strain. But push it too hard and things start to go wrong. In the first place, you’ll start to get dehydrated, even as your heart rate rises and your blood pressure falls. That, in turn, can quickly lead to more serious problems. Fainting and muscle cramps are two of the milder consequences here, the latter perhaps explaining Fogarty’s complaints the day before he died. From there, heat exhaustion and heat stroke can sometimes follow. Neither bodes well. Heat exhaustion brings a range of symptoms, including headaches, nausea and vomiting. Heat stroke is arguably even more worrying, not least given it can lead to confusion and fainting, hardly ideal around heavy mining equipment. At worst, these illnesses can permanently damage the heart and kidneys, and ultimately cause death. Nor are these necessarily remote threats, especially in developing countries.
According to one 2018 study by the Annals of Global Health, for instance, 78.4% of underground workers at one Tanzanian mine suffered from ‘moderate’ heat illness, with nearly 70% of their open-pit colleagues struggling too.
With these statistics in mind, mining operators have obviously felt obliged to act. Click on the BHP website, for instance, and you’ll soon find promises to deploy a range of ‘heat management strategies’ to ensure workers stay safe. In the first instance, that involves machines to physically keep underground tunnels cool. Simple air conditioners are one option here, as are cooling towers that dissipate excess heat via water evaporation. But such solutions come with problems all their own. For one thing, they obviously don’t help people struggling with temperatures out in the open. For another, says Glen Kenny, are the environmental impact of such devices. As the professor of physiology at the University of Ottawa puts it: “From a greenhouse gas emission side of things, it certainly raises a lot of questions about using refrigeration to cool [mines].” Fair enough: air conditioning already accounts for about 20% of the electricity used in buildings today, resulting in 4% of all global emissions.
Buddying up
With these technical limitations in mind, it makes sense for operators to develop robust work policies. Especially with the impact of climate change – experts warn that mine-heavy regions like Northern Australia could have dangerously high temperatures most days by 2100 – that increasingly encompasses a whole list of regulations. At BHP, staff are expected to take regular cool showers, while the MSHA encourages miners to drink a cup of water every 15 minutes. That’s echoed by the need to take strenuous tasks slowly, even as workers should gradually increase their tolerance to extreme temperatures.
All the same, experience shows that mere rules, or even practical experience, are far from sufficient here. When Fogarty collapsed in 2017, after all, Rio Tinto technically had heat policies in place – they just weren’t enforced. More generally, Kenny points out that broad regulations risk clashing with the infinitely subtle circumstances of individual workers. Imagine, he says, two otherwise healthy workers – but one is diagnosed with diabetes. You may not be able to notice at first glance, but once you reach a certain temperature the “person with diabetes may collapse”, Kenny explains. The same goes for if a worker is older, and therefore more naturally susceptible to exhaustion, or if they’re just too young and inexperienced to know better, and instead rush ahead to complete their work quickly, whatever the consequences for their bodies.
With this in mind, it’s no wonder operators are gradually moving away from universal heat stress rules towards a more holistic approach. To an extent, that involves measuring internal and external temperatures – all the better to catch heat stress before it becomes too dangerous. However, if this is increasingly possible using new technology – think sensor-based safety helmets – both Kenny and Yeoman are also enthusiastic advocates of the so-called ‘buddy system’. Pairing two colleagues together, Yeoman explains they can monitor “each other for signs and symptoms of early heat illness”. It goes without saying, moreover, that such close contact makes it far easier to spot diabetes and other hidden ailments before it’s too late.
Feeling the heat
Together with regular training sessions – Yeoman argues both supervisors and workers should be refreshed each year – and it’s easy to be optimistic about the future of mining heat stress. That’s doubly true when you consider recent advances in cooling technologies. Rather than needing to lean on grumbling engines, some insiders are instead making use of the local environment. One option involves borrowing cold water from the bottom of a lake. Another encompasses storing winter snow in a pit, or even mixing water with cold air, using the ice that results to keep mine shafts cool. Nor is this just a theoretical solution. In Ontario, to give one example, miners used this approach at the Frood-Stobie facility, which produced nickel from 1955 until 2017.
Of course, such tricks are harder to pull in the Australian outback – particularly unfortunate when you remember that climate change is only going to get worse through the rest of the century. “The reality,” Kenny says, “will be we are going to see these temperature extremes, we’re going to see rising temperatures – that means the underground is going to get warmer.” Yeoman makes a similar point about what that’ll mean in practice. “Heat stress will likely be a bigger issue over time,” she warns, adding it could “affect mine efficiency because of the inability of humans to tolerate working in very hot areas for prolonged periods.” Ironically, that last point might kindle the sector to hunt for further solutions. For if Rio Tinto’s treatment of Fogarty suggests workers can sometimes be treated as expendable by this industry, profit never is, no matter how hard the sun is shining.
This article first appeared in World Mining Frontiers magazine.