The world's biggest mining companies saw their results crushed last year and their stock market values slashed in one of the toughest years in memory, a report by PwC says.

The report says the top 40 mining companies in the world saw their collective stock market value drop $280 billion or 23 per cent in 2013 as they booked $57 billion in writedowns.

2013 saw commodity prices, led by gold's greatest annual decline in 30 years, fall significantly. Miners are also finding the ability to operate in all corners of the world difficult, as governments pushing to get a bigger piece of the pie in the form of royalties and taxes.

The industry saw profit fall by 72 per cent to $20 billion, the lowest it's been in a decade.

One Canadian miner that has been particularly hard-hit is Barrick Gold, which reported a $2.83 billion loss in the last quarter of 2013.

Barrick has been struggling, with production at its Pascua-Lama mine on the border of Argentina and Chile halted last year. It has recently struck a deal with opponents of the mine that may allow it to resume production.

The miner also unloaded a pair of Australian mines in hopes it can return to profitability.

But the industry isn't standing still during these tough times, according to John Gravelle, PwC's global mining leader and author of the report, who says "the industry is adjusting to tough times in the short-term with strategies in place to regain confidence."

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

Canada is one of the largest mining nations in the world and mining accounts for about 19 per cent of Canadian exports.​ The TSX and TSX Venture exchange list more than 1600 mining firms, the most of any exchange in the world.

with files from the Associated Press