An Australian court on Wednesday revoked approval for a project to build one of the world's biggest coal mines.

"The Federal Court has formally set aside the approval of the Carmichael Coal Mine and Rail Project," Australia's Environment Department said in a statement.

The 11.7 billion US dollar mine had been approved by the Australian government in 2014, but conservationists challenged the approval.

Environmental pressure groups argued the government's go-ahead for the project was wrong because of the amount of greenhouse gases it would create and because of its potential impact on vulnerable species. They had also said the transport of the coal to a port could have a negative effect on the Great Barrier Reef, one of the world's most biodiverse areas.

Bad news for Adani

The Mackay Conservation Group, which had brought the legal challenge, said not enough consideration had been given to advice on two vulnerable reptiles, the yakka skink and the ornamental snake. Both are only found in Queensland, the state where the Carmichael project was to take off.

Wednesday's court ruling is the latest setback for the Indian firm Adani, which owns the mine. Major European and US banks had ruled out providing funds for parts of the development costs over ecological concerns.

The mine had been forecast to produce about 60 million tons of thermal coal a year for export and was to provide electricity for up to 100 million people in India, while creating thousands of jobs in Australia.

Adani called the ruling "regrettable," saying it was committed to ensuring its mine, rail and port projects in Queensland were developed and operated in accordance with Australian laws.

hg/bea (AFP, LUSA, dpa)