BHUBANESWAR, India, Aug. 6 -- Indian state-run National Aluminium Co Ltd sold 30,000 tonnes of alumina for $320.57 a tonne free on board this week, a company source said on Thursday.

The alumina, to be shipped this month, was purchased by Switzerland-based Glencore AG, said the source who is close to the tendering process but could not be named due to company policy.

NALCO, the tenders of which serve as an international benchmark, last sold alumina to Hong Kong-based Noble Resources, for $378 a tonne free on board in May.