MONTREAL -- Mining giant Rio Tinto has frozen the salaries of its global non-unionized workforce, including many in Canada, as it prepares to weather an expected tough year.

In a note to employees, CEO Sam Walsh said cost-cutting efforts over the last three years have not been enough to offset falling metal prices and the "very sobering" outlook for 2016.

"From the CEO down, we are implementing a salary freeze for 2016," he said.

"This decision was a very difficult one. I'm sure you are disappointed by it, as am I, but it is necessary given the market context."

It marks the first wage freeze in more than a decade for Rio Tinto's global aluminum division, which is based in Montreal.

The company's Canadian operations, which also include non-aluminum operations, have a total of about 12,000 employees. The number of non-unionized workers was not available.

Although bonuses will continue, Rio Tinto is also limiting travel by making better use of technology.

Walsh said the global economy remains sluggish as China's economic growth has fallen and demand has shifted from metals-intensive sectors like infrastructure and construction to consumer spending.

China accounts for as much as 40 to 50 per cent of global commodity demand, according to consultants PwC. Its economic growth is forecast to drop below seven per cent a year from double digits in recent years and commodity prices are tracking it lower.

Commodities prices are around the 2005 levels or lower. Rio Tinto has been particularly hit by the dramatic drop in iron ore prices, its largest commodity.

The price of copper has dropped about 30 per cent in the past year and gold 11 per cent, while the price of iron ore has about halved. Many companies have responded by cutting costs and reducing capital spending.

Anglo American announced last month that it was shedding 85,000 employees or more than 60 per cent of its workforce and reassessing its huge operations to cope.

Walsh warned that the pressure won't let up.

"This situation is not temporary and our industry is now moving into the new normal, which means we must continue to be one step ahead."

With files from The Associated Press