One in the eye: Mining’s cyclone peril

In the summer of 2007, Cyclone George formed in the Top End of the Northern Territory before tearing a path through Western Australia’s Kimberley coast, eventually reaching a peak at Port Hedland and carrying on into the Pilbara.

One of the worst tropical cyclones in Australian history, the Category 5 ripped through Fortescue Metals Group’s mining camp (which was only designed to withstand up to a Category 2 cyclone), flipping several dongas.

The incident resulted in the deaths of two workers and injured many more. Fortescue was cleared by the Supreme Court of Western Australia in 2012, but it brought into stark relief the overwhelming danger and damage that cyclones could cause.

Mine sites in vulnerable areas, such as coastal and inland Queensland and the north coast of Western Australia (the area between the towns of Broome and Exmouth is considered of the most cyclone-prone regions of Australia) have to be aware of the risks.

This is particularly the case in summer; the 2018–19 cyclone season officially commenced last November and will run until the end of April, though tropical cyclones can form at any time of year.

According to Neil Bennett, Western Australia media and communication manager at the Bureau of Meteorology, mine sites on both the coast and inland have to prepare not just for the punishing gusts that can reach in excess of 220 kilometres per hour, but another elemental danger as well.

“The wind is the thing everybody looks at and thinks, ‘Oh, that’s really bad,’ but it’s also the water as well,” he explains.

“Flooding is a major issue. These systems, even as they transition as we call it and weaken from tropical cyclone status to tropical low status, can still produce some very heavy rainfall and that will lead to flooding.”

Bennett suggests that mine sites need to ensure the structural integrity of buildings on site to make sure they are compliant with safety regulations. Sites should also ensure they monitor the warning signs of impending winds and have an evacuation plan in place should a cyclone be on the way.

As cyclones travel inland they weaken and develop into an ex-tropical cyclone (called ‘post-tropical cyclones’ in the United States). These ex-tropical cyclones (or post-tropical cyclones) are generally divided into two types; extratropical cyclones and remnant lows.

Though ex-tropical cyclones are weaker than full cyclones — tropical lows have a maximum wind speed of 34 knots, or about 63 kilometres per hour — they can still be damaging, especially if they result in heavy rainfall.

“We are constantly monitoring the weather and we do use the Bureau of Meteorology’s information, such as their cyclone watch and warning system, to determine the severity of a cyclone, which assists in how we respond,” Anglo American executive head of underground operations, Glen Britton says.

Anglo American’s underground operations make use of surface infrastructure such as coal handling and processing plants (CHPP), gas drainage systems and ventilation equipment that is vulnerable to exposure and needs to be secured.

The company’s coal output suffered in the wake of 2017’s Category 4 Cyclone Debbie, which had a significant impact on Queensland’s rail network. This resulted in delays to processing and railing stocks.

BHP faced similar issues related to the rail network, affecting its Bowen Basin operations, while Glencore had to temporarily suspend its Collinsville and Newlands mines due to flooding.

Anglo American takes extensive measures during tropical cyclones to make sure its workers remain safe.

During Cyclone Debbie, the company worked closely with its suppliers to ensure sufficient food was available at its camp. The company also opened the camp to employees and their families due to local power supply disruption to local power supplies.

Following the cyclone, the team then worked to restock perishable items and help the community with clean up operations.

“In severe cases, like cyclone Debbie [in 2017], we convened our crisis response team and activated our trigger action response plan,” says Britton.

“The team met regularly to review the situation, assess risks and impacts and adjust our approach as required.

“In that situation we decided to ensure our people were safe so suspended operations early so they didn’t have to travel to work or could travel home to their families if they lived in affected areas.”

This is the type of preparation that is needed once again with cyclone season in full swing.

This article also appears in the January – March edition of Safe To Work.