After eight years of delays and uncertainty, Indian energy giant Adani is approaching crunch time on its controversial $16.5 billion Carmichael coal mine in central Queensland.

Adani Australia's chief executive Jeyakumar Janakaraj – known in the industry as "JJ" – late last year set a March 31 deadline for the company to find the remaining funds for the $6.7 billion first stage of the mega-mine, which would be the largest open-cut coal mine in Australia.