A Vale spokesman confirmed that at this stage the company had advised employees of its intentions and started a consultation process with employees, their representatives and key external stakeholders.

The company, which has been trying to sell the Glennies Creek underground and Camberwell open cut mines that form part of the Integra complex, said the decision was due to the unsustainable financial losses of the operation due to the current market conditions.

Construction, Forestry, Mining and Energy Union district secretary Peter Jordan told AAP it would be meeting at the mine on Wednesday.

“The workers are all in shock at the moment and the anger is starting to set in, there's no doubt about that,” he reportedly said.

“Integra's telling the employees that it's due to lower coal prices and the high Australian dollar.

“We've got 350 members engaged at both the mines and when you add support staff to that you’re talking about 500 Integra jobs.”

In the first quarter of 2014, Integra Coal output was 8.6% lower than in the 2013 fourth quarter but 76.4% higher than in Q1 2013.

In Q4 2013 the company accessed better geological sections of the mine.

Integra coal production totalled 379,000 tonnes of metallurgical and 48,000t of thermal coal.

Vale is in negotiations to sell at least 15-25% of its coal portfolio across Australia and Mozambique to focus more on its core iron ore business.

“We are looking to sell a stake of between 15 [and] 25% but we are flexible, depending on the proposal,” Vale coal and fertiliser division head Roger Downey said in a London press conference, according to Reuters.

Vale’s efforts to diversify into coal ramped up in 2007 when it advanced the Moatize project in Mozambique and established its Australian coal business by purchasing stakes of the Carborough Downs, Isaac Plains and Integra coal mines plus exploration assets from private company AMCI for $A835 million.

With its slice of the global iron market slipping since, Vale’s strategy is to expand its iron ore production capacity from 306 million tonnes in 2013 to 450Mt in 2018.