The Liberal National Government has approved the expansion of Rio Tinto's Silvergrass iron ore mine, near Tom Price in the Pilbara.
State Development Minister Bill Marmion said capital expenditure on the project was expected to be $441 million.
"This project will create about 500 jobs during construction and an additional 25 operational positions once the expanded mine is fully operational," the Minister said.
"Expanding production from Silvergrass will allow Rio Tinto to sustain the quality of their Pilbara blend product and maintain current production levels.
"The expansion provides a significant boost to the Western Australian resources sector and shows our State continues to be an attractive place for large-scale investment."
The Silvergrass proposal was approved under the existing State Agreement between Rio Tinto and the State Government. The construction phase of the project is expected to start immediately.
This evening, Mr Marmion will open Rio Tinto's annual Colours of our Country Aboriginal art exhibition.
"This event provides the people of Perth with a snapshot of the art, stories and customs of traditional owners in the Pilbara region," he said.
"The exhibition is part of Rio Tinto's commitment to delivering substantial benefits to Western Australian communities.
"Last year, exhibition sales generated more than $245,000 for the artists, art groups and communities involved. Since 2006, Colours of our Country has raised more than $2 million."
Western Australia's iron ore exports were valued at $49.8 billion in 2015
Rio Tinto celebrated 50 years of iron ore exports from the Pilbara in August this year
The Colours of our Country exhibition runs from Monday, September 5, 2016 to Friday, September 16, 2016 in the foyer of the Central Park building, 152-158 St Georges Terrace, Perth
Minister's office - 6552 6800