An estimated $22.5 million was spent on exploration for minerals other than petroleum in the year to March in trend terms, the Australian Bureau of Statistics said.

That included quarterly spending of $6 million or more in the two most recent quarters.

Quarterly spending had not hit $6 million since 2014.

The annual spend of $22.5 million was well ahead of the $13.1 million spent in the previous year, but well behind the $40.7 million spent in the year to March 2013.

Savage River iron ore miner Grange Resources recently committed $10 million for studies into potential  underground mining.

Its plans included “sustaining its current operations by reinvesting into key areas of production, as well as future development plans to undertake feasibility studies for Centre Pit, Long Plains and underground access to the ore body in North Pit,” chief executive Honglin Zhao said.

“We believe the success of these plans will create additional long-term value in the company and to our shareholders.”