Alcoa refineries safe from WA bushfire

Metals giant Alcoa says its West Australian alumina refining operations have not been affected by the Waroona bushfire but its Farmlands business has sustained some damage.

The Farmlands offices, comprising two buildings south of Hamel, have been destroyed and there has been some damage to fencing.

The company said it was not aware of any livestock loss.

Alcoa evacuated a skeleton staff of up to 15 people from its Willowdale facility before midday on Thursday.

The Australian Manufacturing Workers Union raised concerns that staff had been requested to attend work at the Willowdale mine in Pinjarra on Thursday morning.

An Alcoa spokeswoman said four fire crew staff had been asked to assemble in Pinjarra, but had been stood down before arriving.

An emergency bushfire warning for Waroona, south of Perth, was extended on Thursday to Harvey and surrounding areas including Preston Beach in the state's Peel and South West regions.

The fast-moving fire, which was sparked by lightning on Wednesday morning, had so far burnt 11,000 hectares, the Department of Fire and Emergency Services said.

The US-based aluminium producer operates three refineries in the region at Kwinana, Pinjarra and Wagerup, with a combined capacity of 8.8 million tonnes a year.

It also manages 19,000ha of rural landholdings at Pinjarra, Wagerup and Boddington.

The Alcoa Farmlands unit mainly produces about 2000 tonnes of beef annually, but also supports a cattle backgrounding enterprise, an 800ha cropping program and grazing of 3000 sheep.