Iron ore exports at Australia's largest bulk commodity port have increased 28 per cent on a year ago as the nation's biggest iron ore miners increase volumes.

The relentless cost drive dominating the iron ore industry entered its latest downward spiral yesterday, with the first 100 of an expected 800 Rio Tinto workers laid off across some of the giant's biggest minesites.

Woodside Petroleum's proposed US$3.75 ($4.8) billion acquisition of a portfolio of Apache assets cleared a key hurdle this morning when it won approval from Australia's competition regulator.

The local bourse has opened in the red following losses from market heavyweights BHP Billiton and Rio Tinto.

Iron ore miner Fortescue Metals Group is looking to refinance US$2.5 ($3.20) billion of its debt.

Three tiny rocky outcrops discovered 300km off Western Australia's north-west coast have become the world's most valuable real estate, worth at least $5 billion to state coffers in gas royalties.

A legal technicality and Western Australia's Labour Day public holiday has left the receivers and creditors of Griffin Energy facing a $150 million shortfall on the sale of its Collie coal business to Lanco Infratech four years ago.

Macmahon Holdings has laid off another 50 workers under measures to restructure the business in the wake of losing its biggest contract.

Liquefied Natural Gas Limited has signalled its intention to seek dual listing in the US once it begins construction on its Magnolia LNG project in Louisiana.

The world's peak energy security body is urging Australia to build a massive system of underground oil tanks to insulate itself against the increasing risks of a disruption to supplies.

Mining billionaire Andrew Forrest has revealed an ambitious plan to join forces with Chinese investors to open up vast tracts of northern Australia for irrigated agriculture.