The company reported varying concentrations of coarse grained and fine grained rare earth element mineralisation observed "in multiple domains" during core logging of the 1,020m hole.

Speaking to reporters on the sidelines of Diggers & Dealers in Kalgoorlie, vice president upstream Kam Leung said there was a lot of work to do yet but "I can just tell you our guys are very excited".

The company last week reported record sales of A$185.9 million for the June quarter and total REO production of 3778 tonnes. 

It has A$680 million in the bank and has earmarked $500 million for a new processing plant in Kalgoorlie, which Leung said would become one of the pillars of its business and provide a platform to expand production.

Leung said the plant had to be built by mid-2023.

"We're focused on meeting that timeline," he told reporters.

He expected environmental approval by year-end.

In terms of further growth, Leung did not rule out merger and acquisitions activity.

"I think we've got all the fundamentals in place for strong growth," Leung told the conference.

Lynas is the only significant producer of separated rare earths outside of China.

It has a processing plant in Malaysia and signed a contract with the US government in January to build a light rare earths processing plant in Texas.

It has also separately submitted detailed engineering and design work to the US government for a heavy rare earths facility.

Lynas shares have trebled over 12 months and were up slightly in afternoon trade to $7.36, valuing it at $6.6 billion (US$4.8 billion).