Indian billionaire Gautam Adani's Australian mining firm has bagged approvals to build a railroad for a $15bn coal project in Queensland, bringing it a step closer towards taking a final decision on whether to proceed with the venture.

The state of Queensland has approved the A$2.2bn ($2bn, €1.5bn, £1.2bn) North Galilee Basin Rail project, a 300 kilometre (186 mile) railway line to connect the Carmichael mine and potentially other mines in the Basin to the Abbot Point port on the east coast, reports said.

Adani has already mandated South Korea's Posco Engineering & Construction to build the railroad.

Adani Mining's Australian venture will fuel India's coal-starved power plants and could provide electricity to some 100 million people in Asia's third-largest economy. Coal could also find its way to China.

At full export capacity, the project is expected to contribute almost A$930m to the Mackay region's gross regional product (GDP) and A$2.97bn to the Queensland economy each year for the next 60 years.

Operations are subject to strict conditions to protect groundwater and the environment, Australia's environment minister Greg Hunt has said.

However, environment groups like Greenpeace have voiced their concerns about the likely damage the mining and export operations will inflict on the local environment and on the Great Barrier Reef.

"Adani looks forward to continuing to work with our project partners and all levels of government to see this through," Adani Mining said in a statement, Reuters reported.