Encounter shares shot to an 11-year high in June after intersecting niobium-REE mineralised carbonatites at Aileron in the West Arunta region, an emerging critical minerals province which also hosts neighbour WA1 Resources' recent niobium-REE discoveries.

Aileron is one of Encounter's key 100%-owned projects, along with the Sandover copper and Junction lithium projects in the Northern Territory and the Lamil copper-gold project in the Paterson Province.

The experienced explorer also has four major copper farm-in projects with three leading miners, BHP and South32 in the NT and IGO in Western Australia, with their focus reflecting the world's forecast shortage of the red metal.

"It's an exciting time to be in exploration generally," Encounter managing director Will Robinson said.

"I think most of these commodities, that are going to be required over the next 50 or 100 years, are constrained by the lack of discovery success and we think we have a pretty important role to play.

"Our partners have major exploration programs in progress and the West Arunta project is our priority 100%-owned project."

West Arunta winner after thwarted start

Encounter had identified the opportunity about five years ago at Aileron, in WA's West Arunta near the NT border, and secured the tenure in 2019.

It established a 30km track to open up the area in 2020 and got 158m into the first drill hole, EAL001, co-funded by the WA government, before a mechanical failure meant the team had to demobilise, Robinson explained. 

Undeterred, the company conducted gravity and magnetic-radiometric surveys in 2021 and 2022, followed by the project-wide Falcon airborne gravity survey earlier this year which highlighted a suite of additional high-quality targets.

"This Falcon survey was a major undertaking and one of the biggest privately funded belt-scale gravity surveys completed by a junior," Robinson said.

Drilling returned to the project in May and resumed hole EAL001 at the Hoschke target, recently renamed after geophysicist Terry Hoschke who had identified the magnetic anomaly.

That first diamond drillhole returned 16m at 0.6% niobium pentoxide and 0.2% total rare earth oxides from 350m.

Two additional holes over a strike extent of 3.5km also intersected niobium-REE mineralised carbonatites.

Robinson said the strike length indicated pretty significant mineralisation.

"We're just getting started," he said.

An RC rig was booked for a 10,000m program between August and October, to follow up the results and test new targets identified by the Falcon gravity survey.

"It's a region of completely unexplored paleoproterozoic geology under shallow cover," Robinson said.

"Geology of this age hosts some very large ore bodies in a whole suite of commodities including the major IOCG copper deposits in South Australia.

"I've got the feeling that this is shaping up as a new mineral province.

"It's remote but the shallow cover makes it readily explorable and we've just scratched the surface."

He said Encounter was keen to apply conventional technologies, such as surface geochemistry, gravity and magnetics to target the opportunities.

He also pointed out the benefit of the targets being under shallow cover.

"Particularly from an IOCG copper perspective, the industry has been targeting similar packages under 500m of cover in South Australia for the last 40 odd years," he said.

"We've got this similar geological package coming close to surface, within 5-10m."

Drawing on experience

Robinson said Encounter's success was due to its exploration team, including having two very high calibre and respected geologists on the board, Peter Bewick and Dr Jon Hronsky and experienced exploration managers Sarah James and Mark Brodie.

"We're very disciplined in our approach to capital and making decisions to partner projects where appropriate and test targets ourselves where we can," he said.

"And we've got a terrific team of geologists who've been able to explore in remote locations … and continue to generate and test new ideas." 

Robinson said Encounter had also been quick to move on new government data sets and had been one of the first into the Paterson Province, acted swiftly in the NT after the government's Exploring for the Future program and was an early mover in the West Arunta.

"We've very much targeted these frontier areas, that are under-explored in the tier one jurisdiction of Australia," he said.

"We think central Australia is vastly underexplored and has the potential to be a major source of many of the metals that the world's going to require in the next 50 to 100 years."

Partner progress

Encounter's business model is based on a hybrid partnership and 100%-owned model, with the goal to have A$5-$10 million a year going into the ground by partners to provide a baseline of exploration activity, Robinson said.

Encounter had about $12 million in the bank mid-year and Robinson said the company's partners were set to spend around $7 million again this financial year on the farm-in projects.

"All up, we've got a sizable investment in exploration across the portfolio," he said.

IGO began drilling at the Yeneena farm-in project in the Paterson Province in July, to follow up on results of up to 1% copper from a 2016 campaign.

IGO is funding the program under a $15 million earn-in agreement.

In the NT, South32 has started drilling at the Jessica copper project, which was recently expanded by about 60% to circa 10,300 square kilometres along key structural corridors east of Tennant Creek, prospective for sediment-hosted and IOCG-style copper.

Drilling would then shift to the Carrara copper-zinc project.

South32 can earn an initial 60% of both projects by spending $15 million and $10 million respectively on exploration within 10 years, under a deal struck last year.

Also in the NT, BHP began the first diamond drilling project in October at the Elliott copper project, under a $25 million earn-in agreement.

Gearing up for 2024

Back in the West Arunta, Robinson said the objective was to gather as much information as possible before November to help design the exploration program for next year. 

A plethora of drill results are anticipated in the coming months.

"We need to build our team to be able to deliver what's hopefully going to be a major program in 2024," he said.

"Having a project that's advanced so rapidly in the space of six months, everything else has had to take a bit of a backseat.

"But the other projects haven't gone backwards as a result of the success that we've had in the West Arunta.

"Instead, it might provide us with the catalyst that enables us to go faster elsewhere as well.

"We're gearing up for what's going to be a very, very big 2024."