Commodities group Glencore is putting two copper mines, in Australia and Chile, on sale.

The company said Monday it is initiating the sale process for the Cobar mine in Australia and the Lomas Bayas mine in Chile in response to "a number of unsolicited expressions of interest for these mines from various potential buyers."

It invited bids for one or both mines and the process "may or may not result in a sale."

On Friday, Glencore said it is slashing its zinc production by a third in response to a sharp fall in the price of that metal. The company's shares have been under pressure as investors worry about the impact of falling commodity prices on earnings and its ability to meet its debt repayments.