Sydney: India’s Adani Group could walk away from its $16.5 billion Carmichael coal project in Australia unless a royalties deal can be reached with the state government, according to federal resources minister Matthew Canavan.

The Queensland government’s failure to agree the terms of the royalty regime for the mine may jeopardize the development in the state’s Galilee Basin, Canavan said in a phone interview on Wednesday. Adani was due to make a final investment decision on 29 May for the Carmichael mine, but deferred that on Monday citing uncertainty over royalty payments.

Adani’s approval for the project “is contingent on the Queensland government coming to a decision on their royalties policy", Canavan said. “You can’t expect Adani to make a multi-billion dollar decision if they don’t know what tax they will pay. The ball is now in the Queensland government’s court."

Australia’s largest coal project—which could fuel power generation for 100 million Indians and create 10,000 jobs in Queensland—has been delayed several times since first being proposed in 2010 due to protests and court claims from green groups concerned about its environmental impact. Westpac Banking Corp. barred lending for the project in April due to a new policy on coal emissions. Gautam Adani, the billionaire chairman of Adani, said in March it could start mining coal from Carmichael in 2020.

An earlier royalties deal proposed by the state in March would see Adani pay less in the early years of the project but the same overall sum over the 60-year life of the development, Canavan said.

The office of Annastacia Palaszczuk, premier of Queensland, didn’t immediately respond to a voicemail request for comment. Bloomberg