Indian energy giant Adani is weeks away from pulling the trigger on its controversial Carmichael mine in Central Queensland after scaling back its size and scope to convince banks to finance the project.

While many industry experts doubted the economics of the original $16.5 billion Carmichael project - which planned to export 60 million tonnes of thermal coal each year making it the biggest coal mine in Australia - the project has now been scaled back to a capital cost of less than $2 billion for the first stage.