South32, which was spun out of BHP Billiton, is cutting more than 600 jobs and preparing for a $1.7 billion write-down.
The mining group, which mainly operates in Australia and South Africa, has endured a brutal inauguration as an independent company since it was floated on the London, Sydney and Johannesburg markets last year.
It took its first solo steps into a market where the prices of the manganese, coal and nickel it produces were plunging. The company has halved in value in its first nine months, leaving it worth £3 billion, or about a third of the valuation mooted in the City a year ago.
The company said it was significantly cutting the output of its manganese joint venture in response to lower prices.