The commodities producer (AWC) reported net profit of $US122.0 million for the six months through June. It recorded a loss of $US47.4 million in the same period a year earlier.

Alumina said its profit margin widened as it reduced its cost of making alumina by $US30 a tonne, while at the same time the price it received from customers rose to $US321 a tonne from $US300.

A year earlier, it also faced one-off costs from the closure of the Point Henry smelter in Victoria.

Alumina’s key asset is a 40 per cent stake in the Alcoa World Alumina and Chemicals venture with Alcoa, the world’s largest alumina producer.

The company said it would pay an interim dividend of 4.5 cents a share. It didn’t offer a midyear payout in 2014, and gave shareholders a final dividend of 1.6 cents.