NEW DELHI - India's Adani Enterprises could theoretically win environmental approval for construction of the Carmichael coal mine in Australia in the next two years, a Queensland state resources official said, despite opposition from activists concerned about its impact on the Great Barrier Reef.

The firm, which plans to start producing around 10-million tonnes of coal a year and eventually ramp up to 27.5-million tonnes, has been at loggerheads with environmental activists in the eight years since the project was first proposed.

The comment on potential approval came in an interview with Caoilin Chestnutt, Queensland's Resources Investment Commissioner, on the sidelines of the Coaltrans conference in New Delhi late on Wednesday. Her agency is not responsible for issuing environmental approvals for the project, which is regulated by Queensland's Department for Environment and Science.

Chestnutt told Reuters she believed environmental clearance for the project could in theory be given in the next several months. Carmichael is one of the world's biggest greenfield coal projects in recent years.

"I would guess, but it is an absolute mess, six months to two years," she said. "They (Department of environment) have said they (Adani) have to go back to the drawing board and draft a management plan."

The Queensland Department for Environment and Science has said two approvals were required, one relating to a plan to protect an endangered bird species, the black-throated finch, and another to identify the source aquifer of ground water in the area.

Chestnutt said protests against the mine were a "hindrance" and that there was a lot of misinformation about the mine that needed to be challenged.

Asked what she considered "misinformation", she said, "I think people just think that coal is dirty and global warming is a major issue, and people just like to blame the coal business for that, CO₂ for that."

A spokesman for Adani said the firm expected to move faster on the project in future.

"We have provided all required information data and feedback needed for this process to be completed and accordingly we expect to have these plans approved in the very near term," the spokesman said in an emailed response to Reuters.

The company last week slammed a report on the endangered bird which was reviewed by the Queensland government, calling it "an anti-Adani lobbying document, dressed up as science," and said they wanted to advance their project.