The survey, funded by the Australian Research Council and the Construction Forestry Mining and Energy Union, is an attempt to measure the growing impact of mental health issues on mining sites.

In the first part of the survey, Griffiths University’s Professor David Peetz, Associate Professor Georgina Murray and Dr Olav Muurlink gathered data from close to 4500 survey participants, including 2566 CFMEU members and 1915 partners.

The survey showed 50% of employees who took part were working more hours than they would prefer, even after taking into account how that would affect their income and other activities.

“The findings in the [first] report are very much preliminary,” Prof Peetz said. “Wave two will be important as it will examine the same population in 2013 and give us better information on how things change over time – and therefore, what causes what.

“However, we can say at this stage that for those workers who clearly want and are unable to attain fewer hours of work, there appears to be a significant upward impact on depression, and a greater use of sleeping tablets, antacids and antidepressants.

“The respondents showed sleeping difficulties. And when you had lack of control combined with wanting to work fewer hours, it not only made mining and energy workers more likely to feel unsafe, it also had negative health effects, including on psychological health.”

CFMEU general secretary Andrew Vickers said: “The researchers have kept at arm’s length from the union and we’re happy that this has been the case.

“It helps ensure the independence and integrity of the findings. And it helps us to objectively identify some important issues the union must face.”

Mining and energy workers, and their partners, were less satisfied with their free time or with how much they felt part of their community than were the broader Australian population, Prof Peetz said.

“Workers with no say over their hours and shifts seemed to have more difficulty sleeping, and be more likely to feel unsafe at work, or on their way to or from work,” he said.

“They were more likely to feel too tired or emotionally drained to do things they should at home.

“The lack of say had a flow-on effect. Their partners often confirmed that their spouses were indeed too tired or emotionally drained to function properly and that it affected them.”