ADANI Australia has promised to explain why it failed to tell the Federal Environment Department key details about the environmental history of its chief executive.
But while department officials wanted answers by Friday this week, they told a Senate Estimates hearing the company instead offered to explain the discrepancy within two weeks.
The company that is behind the massive Carmichael mine proposal in central Queensland earlier this year enlisted as chief executive Jeyakumar Janakaraj.
He was previously a director of a Zambian iron ore mine that was charged in 2010 over a major pollution spill during his tenure.
But despite the department asking for a detailed environmental history of Adani Australia and three of its parent companies, public servants said Friday that information was not included.
Environment Minister Greg Hunt had approved the Carmichael mine without such details to hand, the public servants confirmed.
Departmental officers said it was not unusual for mine proponents to provide such information, rather than the department undertaking its own investigations, consistent with the environmental assessment process.
The controversy follows Mr Hunt's re-approval of the mine after it was challenged in court, with the court finding key conservation advice was not considered in the first approval.
Public servants told Senate Estimates they had since put in place new checks to ensure such information was taken into account.