Mining company Rio Tinto Exploration has been fined $80,000 and ordered to pay $7,500 in costs after three workers were exposed to extreme heat conditions without proper training.
The company pleaded guilty in the Perth Magistrates Court for failing to ensure the safety of employees.
On 14 October 2017, two workers and a supervisor were searching for proposed drill sites in rugged terrain while working at Mount Windell in the remote Pilbara region of Western Australia.
The work took place over two days in temperatures estimated to be higher than 37°C.
Workers walked more than 16km in heat
On each occasion, the trio were required to walk more than 16km each day in harsh conditions, carrying equipment and supplies.
According to the WA Department of Mines, Industry Regulation and Safety, Rio Tinto Exploration had various policies and procedures in place concerning the risks associated with exposure to extreme conditions, including hydration monitoring, recognition of heat stress symptoms and appropriate management.
However, the workers conducting the reconnaissance did not understand they were required to complete heat-stress assessments, a procedure which indicates muscle cramps and dehydration are symptoms of heat stress that can lead to life-threatening conditions such as heat exhaustion or heat stroke if not appropriately managed.
At the end of the second day, one of the workers collapsed and later died after complaining of leg cramps and that he felt dehydrated the day before.
“While other factors contributed to the worker’s death, it is difficult to predict an individual’s susceptibility to heat stroke and it can occur very suddenly. A person suffering heat stress must receive immediate treatment with appropriate cooling,” the department said in a statement.
Temperatures were likely above 37 degrees
The exact temperature of the work site is unknown, although the nearest weather station at Wittenoom, 48kms from the incident, recorded temperatures of 37.8°C on the day of the employee’s death and 37.4°C the day before.
Acting Mines Safety Director at the department, Sally North, said employers must ensure workers understand that exposure to extreme conditions – including hot, humid temperatures, while undertaking demanding work – can lead to heat stroke.
“The company had written procedures in place, but they were not well known or understood by some workers or enforced by some supervisors,” North said.
“As at October 2017, the company did not provide these workers with a specific training program to educate them about the causes, symptoms and treatment of thermal stress.”