Billionaire businesswoman Gina Rinehart has dramatically scaled back plans for the country’s next major iron ore mine as part of efforts to overcome concerns from environment regulators and native title custodians about heritage protection, vegetation clearing and carbon emissions.

The Mulga Downs mine that Mrs Rinehart’s private companies plan to build in the Pilbara region will now produce 40 per cent less iron ore than was expected two years ago, according to documents filed with the Western Australian government this week.