Perth-based explorer Estrella Resources has uncovered another manganese prospect in Timor-Leste, with portable x-ray fluorescence (pXRF) grades from float going as high as 27.9 per cent manganese.
The company’s new Sauro prospect is just 12km south-east of its Lalena prospect that just last week threw up pXRF results from grab samples going up to 57.2 per cent and 48.1 per cent manganese.
Management says the host formation for the manganese, known as the Noni formation, has already been identified at the Lalena prospect through an impressive strike length of 27km. Fieldwork will now focus on identifying the same formation at Sauro.
Estrella has secured 2019 vintage helicopter-borne magnetics and radiometric data flown at a 400m spacing across its ground and is using the data to home in the Noni formation, which is overlain by a younger limestone package of rock. The company says magnetic data is an ideal tool for imaging areas of high manganese prospectivity under cover, as mineralisation noted in the area to date has been coincident with the presence of iron.
Interestingly, the magnetics data shows a series of large-scale anomalous features coincident with Estrella’s manganese prospects. It suggests the enrichment may be regionally extensive in what appears to be a big south-west to north-east-trending set of magnetic anomalies.
Today’s news follows on from the revelation by Estrella earlier this month of a manganese rock chip, taken from outcrop, which assayed at a massive 60.8 per cent manganese. That chip was taken from the Lalena prospect in the north of the company’s ground where the Noni Formation outcrops.
Estrella Resources managing director Chris Daws said: “The identification of the Sauro prospect is significant as it sits a great distance away from the manganese identified at Lalena and the source of this mineralisation is yet to be discovered. With new discoveries emerging as well as the recent acquisition of magnetic and radiometric data, I look forward to providing further updates as we continue to progress our exploration campaigns across our tenure”.
Following a trip to Timor Leste – and the identification of rocks that looked as though they contained a whole lot of manganese – Estrella applied for and was awarded three exploration and evaluation licences covering 121.5 square kilometres of ground in the Lautém region in the country’s north-east.
An additional 382sq km of ground was also awarded to Estrella in the form of reconnaissance permits. The company says its managing director Chris Daws has been cultivating relationships in Timor-Leste since 2009, anticipating the passing of critical minerals legislation to enable foreign investment.
Following the passing of a draft mining code in 2016 and an updated code in 2021, things were looking good for Australian companies to start seriously assessing the budding mining nation as potential elephant country.
Fieldwork by Estrella revealed multiple areas of outcropping manganese across Lautém where very little modern exploration has been undertaken to date. Subsequent fieldwork confirmed what the company’s geologists had thought, with that super high-grade manganese rock chip raising some eyebrows.
Interestingly, manganese is mined at grades sufficient to feed directly into smelters in West Timor, which is the western part of the same landmass that hosts Timor-Leste. Estrella says the bulk of rock chip samples taken by geologists working for the Timor-Leste Government across Lautém assayed at well above the 40 per cent manganese mark.
Now, with a 60 per cent manganese rock chip of its own and further tantalising pXRF manganese hits from the distant hills, the puzzle seems to be coming together.
Estrella’s exploration concessions will be run as a joint venture (JV) between it and State-owned resource company Murak Rai Timor (MRT). Estrella will take a 70 per cent ownership and MRT will be free-carried for the remaining 30 per cent through to the release of a definitive feasibility study (DFS).
The reconnaissance permits will be 100 per cent-owned by Estrella. All of the tenements are near the north coast of Timor-Leste, about 150km east of the capital Dili.
Estrella is just one of four companies to be awarded mining leases in the country and plans to leverage its position as the first mover to mature its ground and the budding mineral industry simultaneously – with a high level of government cooperation expected.
But the company is not alone in its bid to explore Timor-Leste, as its ground sist alongside operations run by Beacon Minerals, Peak Everest Mining and Melbourne-based Iron Fortune.
The idea of a mining industry in Timor-Leste takes some digestion, but the 85-minute flight from Darwin could mean the local workforce is propped up by Australian mining expertise. Access to the Lautém mining concessions is via 170km of sealed road from Dili, followed by 10km of unsealed all-weather roads.
Estrella says training of its new in-country geological team is underway as detailed mapping and sampling aimed at identifying mineral occurrences on the surface within the concessions has begun.
Additionally, the company is mobilising crushing and other laboratory equipment to Timor-Leste to give it the ability to test and report multi-element pXRF results quickly from within the country. And that is giving the market a close to real-time look at the geochemistry.
Not interested in being delayed by lab assay wait times, the company will also deploy a portable gold detection system, which enables same-day analysis of field samples.
Back in Western Australia, Estrella is also forging ahead with its Carr Boyd and Spargoville projects near Kalgoorlie and Kambalda, respectively.
In August last year, the company deployed a world-first helicopter-borne TargetEM electromagnetic survey with the aim of identifying sulphide material capable of hosting nickel, copper and platinum group elements (PGE) at Carr Boyd.
The 253-square-kilometre survey identified multiple bedrock-conductor anomalies, including one through more than 5km in strike length and related to the Colreavy Komatiite. A new 3km-long linear zone was also revealed under cover to the south of the main Carr Boyd intrusion.
Management says on-ground investigation of the anomalies reveal many of them relate to areas of interest identified by the recent exploration review, which combined multiple data sets with research conducted by the CSIRO in 2022. Further processing of the dataset is underway to refine the targets.
At Spargoville, things are little more mature for Estrella, which says the prefeasibility study (PFS) for its 5A nickel deposit outlined the potential of a small-scale mining operation of a high-grade resource body through an underground mine.
The ore reserve at Spargoville is 1043 tonnes of nickel and 24 tonnes of copper from a total of 28,000 tonnes of contained material. Despite the solid resource, the company says it has redirected funds away from Spargoville in light of the global nickel price deterioration in favour of a Timor-Leste-focussed business.
After gaining independence in 2002, Timor-Leste may now be maturing into a global mining mecca for companies searching for metals critical to the clean energy transition. The new Timor-Leste mining code allows for a four-year "exploration and evaluation" period that can be extended with three more two-year periods.
That means plenty of opportunity for Estrella to get boots on the ground and samples collected and assessed.
It is not often a rank exploration endeavour takes the spotlight – the last rush into the wild we can remember was the James Bay lithium land grab of last year, although the Timor-Leste Government seems a little more controlled with their allocation of turf.
Estrella has indicated that fieldwork completed since the concessions were granted suggests the high-grade manganese host formation could be laterally extensive – up to 20km, in fact, and extending into its reconnaissance tenements.
To add some flavour to the mix, historic Portuguese maps assessed by the company suggest there is also copper and gold enrichment within its concession, which warrants further investigation. Management says field mapping has already homed in on the copper-gold host formation as the search for mineralisation continues.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Andrew Duffy
