Australia’s mid-tier miners are doing their best to remain afloat in a tough operating environment but efforts to boost productivity are yet to make an impact on their bottom lines, with ­combined losses for the financial year up 60 per cent to $1.6 billion.

The annual Aussie Mine series by PwC has examined the annual results of the largest 50 miners listed on the ­Australian Securities Exchange with market capitalisations of less than $5 billion. That eliminates the big global miners such as BHP Billiton and Rio Tinto.