All carbonate produced at the plant has been sold or is ready to be sold, with 27 tonnes trucked across the Western Australian-Northern Territory border to Darwin earlier this week.
Meanwhile, company management suggested it would be continuing to progress various financing and development initiatives that have been in train for some time.
Northern Minerals aims to be the "principal supplier of ethically produced rare earth metals" within 10 years.
The Browns Range deposit was discovered 10 years ago.
Shares in Northern Minerals were down 8% to A2.2c in afternoon trade, capitalising it at 58.5c.
The stock was at levels around 8c 12 months ago.
