The world’s biggest mining companies saw their profits crushed and their stock market values plunge by a combined total of $280 billion in 2013, in one of the toughest years in memory, according to a report by PwC.

The accounting and consulting firm said Thursday that the top 40 mining companies in the world saw their collective stock market value drop 23 per cent last year as they booked $57 billion in writedowns, led by weakness from the gold miners.

Meanwhile, combined profits at the big firms totalled $20 billion, the lowest level in a decade.

“The industry is adjusting to tough times in the short-term with strategies in place to regain confidence,” John Gravelle, global mining leader at PwC said in statement.

“For example, we’ve seen new faces at the helm of almost half of the largest 40 mining companies in the last two years.”

Gold miners were hammered especially hard last year as the price of gold fell 27 per cent, its biggest plunge in over 30 years.

The sector accounted for $110 billion of the drop in market capitalization and five gold companies fell out of the Top 40 in 2013. Gold miners also accounted for $27 billion or nearly half of the impairment charges recorded by the top 40 companies.

The report also found that companies in emerging markets fared better as they earned a combined $24 billion, compared with a loss of $4 billion by those in developed countries.

Gravelle said the question remains on which firms will be able to thrive in difficult times.

“Merger and acquisition activity, which was surprisingly subdued in 2013, seems to have started to pick up in early 2014,” said Gravelle.

“And backed by a stronger U.S. economy and continued strong demand from China, the market is impatient to see demonstrable returns from recent strategic choices to deliver against the mantra of lower costs and higher productivity.”

The PwC report noted that nearly half of the top 40 companies changed chief executives over the last two years, with seven firms switching leadership in 2013.

The report said companies have pursued what it called “traditional quick-fixes” to falling commodity prices including cutting workers, slashing costs and deferring capital spending. Others made more fundamental shifts in strategy.

PwC said some companies also looked to simplify and focus on extracting value from higher quality assets as well as share mining infrastructure as a means to reduce costs and risk.