Litchfield Minerals geophysics chases huge sulphides at NT poly-metals play
- Doug Bright
- Aug 12
- 4 min read
Recently ASX-listed critical minerals explorer Litchfield Minerals (ASX: LMS) is on track to this week finish a combined electromagnetic and magnetic geophysical survey of its entire Oonagalabi poly-metallic project in the Northern Territory’s Harts Range.
With a $500,000 capital raise under its belt and its disciplined “fail fast or succeed quickly” approach, Litchfield aims to unlock a 3-kilometre-long polymetallic system rich in copper, zinc and, potentially, gold, silver, bismuth and cobalt.
Litchfield launched a 1015-line-km helicopter-borne VTEM Max electromagnetic and magnetic survey two days ago over its Oonagalabi licence area under a contract with UTS Geophysics. It is using a 200m line spacing over 819-line-kilometres, which is being narrowed to a 100m infill spacing over 196-line-kilometres of high-priority zones.
The survey is targeting conductive massive sulphide mineralisation at depth and is already 21 per cent complete. It is designed to detect copper-zinc-rich sedimentary exhalative (SEDEX) or skarn-style systems, which often host chalcopyrite and pyrrhotite.
SEDEX deposits are a type of metal ore deposit primarily known for their rich concentrations of lead, zinc and silver. They form when metal-rich, hydrothermal fluids are discharged onto the sea floor, precipitating sulphide minerals, which often layer within sedimentary rocks.
Litchfield expects to receive the survey results in September. These will guide a program to drill high-priority conductors, the project’s intriguing priority Bomb Diggity magnetic anomaly/interpreted intrusive body and other potential gold-bearing intrusions.
The VTEM survey is a major step forward for Oonagalabi. We already know from drilling that we have copper-zinc sulphides in the system and VTEM gives us the ability to see the bigger picture - both laterally and at depth. The potential for Oonagalabi to be either a SEDEX or skarn system is exciting, as both are known to host high-grade massive sulphide zones, which VTEM is ideally suited to detect.
Litchfield Minerals Managing Director Matthew Pustahya
Pustahya said the survey would also deliver full airborne magnetic coverage, sharpening the company’s geological models and enabling it to target the project’s most prospective zones with greater confidence.
Litchfield finalised its acquisition of a strategic copper-gold-base metals portfolio, including Oonagalabi, in October last year as part of a strategy to invest fresh capital in the NT.
The deal expands the company’s footprint in an under-explored area ripe with large-scale copper-zinc opportunities, which it wants to quickly advance with disciplined drilling supported by modern geophysics.
Oonagalabi is about 130km northeast of Alice Springs, within the Strangways Metamorphic Complex in the Harts Range, where it is hosted within metamorphosed Palaeoproterozoic sedimentary rocks.
It appears to be a geological analogue of the Jervois zone, which is the NT’s largest base metals deposit hosting more than 10 prospects. Both Oonagalabi and the Jervois zone lie in the territory’s highly prospective Arunta region.
Oonagalabi was first explored in the 1970s, with Russgar Minerals completing 14 percussion holes and extensive mapping and geophysics, followed by Amoco Minerals Australia which put in six reverse circulation drill holes in the early 1980s.
The historical work was not followed up by more recent exploration, leaving Litchfield a tantalising opportunity for acquisition.
The Oonagalabi exploration licence encloses a largely rectangular, east-west oriented area of about 24 square kilometres. It incorporates a 3km-long by 0.5km-wide mineralised corridor identified through historical and modern work, which shows significant promise.
Since its acquisition, Litchfield has undertaken remote sensing and other work, including gravity, induced polarisation (IP) and mineral gas surveys, to identify anomalies at the project.
It has also completed detailed mapping and soil geochemistry across 4km of strike, and has also flown drone magnetics, undertaken 3D data inversions and re-processed the historic IP geophysical results to target the system’s core.
The integrated geophysics has revealed two parallel chargeability highs over 1km strike to more than 500m depth, with coincident magnetic and gravity anomalies at Bomb Diggity, which point to a pipe-like intrusive or breccia target.
To target the high-chargeability IP anomalies, Litchfield kicked off a six-hole, 1646m phase one reverse circulation drilling program at Oonagalabi in early April. The program confirmed a large, disseminated copper-zinc system and highlighted a magnetite–gold-silver-bismuth system indicating a deeper driver near the Bomb Diggity anomaly.
Drilling intercepted copper-zinc sulphide mineralisation in all six holes, with one intercept including 14m at 1.32 per cent copper, 0.86 per cent zinc, 7.17 grams per tonne (g/t) silver and 0.13g/t gold from 104m depth, accompanied by 140m of visual sulphides.
One metal-rich zone delivered 1m assaying 2.86g/t gold, alongside bismuth and silver, linked to magnetite alteration and a potential intrusive body near the Bomb Diggity magnetic anomaly.
Two distinct mineral systems identified by the phase one program include a copper-zinc +/- lead hosted in calc-silicate units, and a gold-silver-bismuth-style mineralisation associated with intense magnetite alteration.
Enhancing the company’s prospectivity appeal, Litchfield has a tight structure with 40 million shares on issue, a low market capitalisation, a lean exploration model and an experienced leadership team.
It has just raised $500,000 through a placement at $0.10 per share, with one free attaching option at an exercise price of $0.10 per two shares.
The company will also offer a $1 million security purchase plan on the same terms, subject to shareholder approval in mid-September. Encouragingly, the board and team have subscribed for 21 per cent of the placement, for a total $105,000, signalling their high level of confidence.
The additional funds will support Litchfield’s year-end drilling campaigns targeting the Bomb Diggity anomaly and VTEM-identified conductors and provide the company with working capital.
Litchfield listed on the ASX in March last year to capitalise on the NT’s untapped potential, where modern datasets and record exploration spending highlight potentially large-scale opportunities. The NT’s prospectivity, supported by federal datasets, positions Oonagalabi as a frontier polymetallic play.
Oonagalabi’s scale and complexity, potentially hosting SEDEX or skarn-style base metals and intrusive-related gold, mirrors deposits such as South Australia’s Prominent Hill project.
While its heavy mineral sands content, of up to 44.9 per cent, may add further upside, the company’s focus remains strongly on copper and zinc, which are long-term critical for the global energy transition.
With its VTEM results due in September 2025 and the next round of drilling slated to kick off this quarter, Litchfield is well poised to test the Bomb Diggity anomaly and its new VTEM conductors.
The company’s data-driven approach, backed by fresh capital and government support, positions Oonagalabi as a compelling polymetallic story in one of Australia’s most prospective regions.
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