Labour market issues were also reflected in increased staff turnover and absenteeism.
The average sales price for rare earths oxide during the half was $48.60/kg.
Roy Hill chairwoman Gina Rinehart says mining is an industry to be proud of.
NRW is set to continue its purple patch with a strong pipeline of work in the order books.
Ellison said 2020 had been the most extraordinary year in the company's history.