Embattled Indian miner Adani plans to develop and run its contentious Carmichael mega coal project in Australia on its own after parting ways Monday with mining services giant Downer.

The massive US$16 billion mine, destined to be one of the world's largest, has been beset with problems, encountering numerous regulatory and legal hurdles, leading to seven years of delays.

A lease was finally granted last year, but environmentalists have maintained a high-profile campaign against it, claiming it will harm the nearby Great Barrier Reef, which is already threatened by climate change.

Adani has struggled to secure funding for the first stage, with a number of global banks choosing to avoid the project, given growing opposition to investment in fossil fuels.