The proposed Adani coal mine, which will be Australia's biggest, has been granted unlimited access to groundwater by the Queensland government in a move farmers fear will drain huge amounts of water from the Great Artesian Basin.

According to a copy of Adani's water licence signed last Wednesday and obtained by Fairfax Media, the $16 billion Carmichael mine merely needs to monitor and report the amount of water it extracts under a permit that runs until 2077.

The mine – one of nine proposed for the Galilee Basin west of Rockhampton – can conduct its own review of its groundwater model without independent or government oversight.

There are also no impact levels specified that will trigger a halt to mining, and the company is able to offset any significant water loss elsewhere, the licence shows.