Glencore chief executive Ivan Glasenberg has denied the commodities giant profits from using child labour.
A BBC Panorama programme will tonight claim children as young as 10 are working in the Tilwezembe concession in the Democratic Republic of Congo. Glencore owns the concession but stopped running it in 2008.
Speaking in his first television interview, Mr Glasenberg, pictured, told Panorama: "We definitely do not profit from child labour in any part of the world. This is adhered to strictly."
He said the children were from an artisanal group that "raided our land in 2010 against all of our authorisation", adding that the company was "pleading with the government to remove the artisanal miners from our concession".
The programme also accuses Glencore of polluting a river in the country with raw acid for three years. Mr Glasenberg said it "has spent vast amounts of money to get rid of this problem, to ensure clean water in two weeks' time will be discharged into that river".
Last week Glencoreadmitted shareholders will have to wait a month longer to receive documents regardings its proposed £23bn merger with miner Xstrata, giving them longer for discussions with the European Commission over the deal.
A number of major investors want the terms to be improved, but according to the Sunday Times Qatar has told Xstrata boss Mick Davis that it will back the plans.