Rio Tinto Group agreed to pay a $28 million fine to settle a six-year investigation by the US Securities and Exchange Commission into its disastrous acquisition of a coal mining business in 2011.

The company said it would pay the penalty without admitting or denying the charges against it. Rio will also retain an independent consultant to advise on its impairment and discourse policies.

The SEC filed fraud charges against London-based Rio and two executives in 2017, claiming they inflated the value of Mozambique coal assets acquired in 2011 for $3.7 billion. The unit was sold for $50 million in 2014 following impairments of about $2.9 billion in 2013 and $470 million a year later.

The SEC alleged that Rio executives had sought to hide the setbacks and their impact on the true value of the assets from the company’s board of directors, audit committee and investors.

Former Rio Chief Executive Officer Tom Albanese also reached a settlement with the SEC and will pay a $50,000 penalty, without admitting to or denying the allegations, the company said Wednesday.