Korea’s Posco and electronics firm LG have inked letters of intent (LoI) to purchase five million and four tons of coal, respectively, while Chinese firms have signed LoI for around four million tons.

Adani spokesperson was quoted by The Economic Times as saying: "We are very excited and confident about the prospects of the coal that will be produced in the Carmichael mine in Queensland, given its high quality."

In August 2010, Adani purchased the Carmichael mine from Linc Energy for A$500m and agreed to pay the royalty stream, which was estimated at more than $2.8bn over the royalty life time.

"Our project has gone through rigorous rounds of environmental approvals and we are very conscious of our responsibilities towards preserving the local environment," the spokesperson told the paper.

Adani’s LoIs come at the time when global coal prices have been significantly declining in addition to oversupply as countries such as China and the US are taking up measures to reduce reliance on coal, to minimize carbon footprint.

In its midyear economic and fiscal outlook, Australia’s Department of the Treasury earlier said that thermal or coking coal prices will remain flat at $63 per ton until mid-2016.