Estrella Resources has received some stunning assay results from rock chip sampling from two new in-situ supergene manganese discoveries at the company’s Lautém project in Timor-Leste, with grades up to a striking 58.6 per cent manganese.
The company also reported a bulk determination for detrital material that has accumulated on the valley floor at the Sica prospect, with assays from 48 large grab samples collected from this transported material averaging 40.1pc manganese. The result is high by anyone’s standards.
The in-situ supergene manganese outcrops at Sica and Estella’s neighbouring Ira Miri project lie on either side of a river valley and are about 4.5 kilometres apart.
The samples have low levels of the contaminants boron, arsenic, phosphorus and silica, making the manganese marketable to the steel industry. Steel quality is improved with the addition of high-grade manganese ores, and it allows for more control when creating specific steels.
Estrella Resources managing director Chris Daws said: “Recent assays from the Ira Miri discovery area and the Sica prospect have confirmed the significant potential for high-grade manganese mineralisation, reinforcing the value of this project. We are also pleased with the systematic sampling of detrital material on the Sica valley floor, which further supports the broader manganese mineralisation across the region.”
Environmental surveys of Estrella’s drilling locations are now complete and applications to develop access tracks and for drilling later this year are being drafted. The company will begin community consultation and education as soon as possible.
Estrella is targeting three different manganese deposit types at Lautém, including primary manganese within a chert formation and a higher-grade secondary manganese in overlying supergene rocks. Natural processes have eroded and transported rock to also accumulate unconsolidated tertiary manganese-rich deposits in current and historic valley areas.
These accumulations could be as significant as at its Sica project and may form a supplementary feed for any future mining operation.
Estrella was one of the first companies to pick up an exploration licence in Timor-Leste (formerly East Timor) in December 2023, as the country marched away from its war-ravaged history. The area is sparsely populated and minimally farmed, which the company says enhances its suitability for exploration.
The region is also well endowed with infrastructure to support a mining operation, is close to major roads and power infrastructure and offers direct access to ports.
Estrella’s nearby Ira Miri prospect includes a striking 3m-high outcropping bed of manganese that the company interprets to be secondary supergene mineralisation derived from underlying manganese-rich cherts of the Noni Formation.
Although the black mineralisation is commonly covered by scree from the overlying limestones, the mineralised trend can be followed over a whopping 4km with primary, secondary and tertiary manganese occurrences. Estrella believes the presence of manganese oxide clasts in the scree hints at supergene mineralisation lying only a few metres below the soil cover.
Estrella sent five samples from the reconnaissance mapping at Ira Miri to ALS’s laboratory in Australia for geochemical analysis.
The secondary supergene outcrop samples have more than 58pc manganese – 75pc manganese oxide - and are very low in the deleterious elements boron, phosphorus and silica. Additionally, the underlying source rock for the manganese graded up to a stellar 20pc manganese.
At the Sica prospect, which was only identified in August last year, is also progressing at pace. Samples of in-situ secondary mineralisation returned manganese levels from a pleasing 46pc to 49.3pc manganese. This secondary supergene area is a flat oxide layer now partially exposed through erosion. The erosion is responsible for concentrating tertiary manganese on the Sica valley floor.
Estrella’s decision to pivot to Timor-Leste is looking to be a shrewd move, especially given its government is looking to diversify the nation’s tax revenue stream away from its richly endowed petroleum minerals base and has a newly enacted mining code for metals exploration.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
