Estrella Resources Identifies Additional Copper Mineralisation at Laleno Dome

Estrella Resources (ASX: ESR) has identified copper mineralisation at five additional sites around the Laleno Dome in Timor-Leste, extending known occurrences across a 12km section of the dome’s northern flank.

The most significant observation was copper mineralisation within an intermediate to felsic igneous rock interpreted from hand specimens as porphyritic, with petrographic analysis underway to test that interpretation.

The rock is hydrothermally altered, extensively fractured, and contains quartz veinlet stockworks with traces of pyrite and malachite, supporting Estrella’s working hypothesis of intrusion-related mineralisation.

Copper was also observed in the Noni Formation at three of the five new sites and in quartz-veined serpentinite at another, adding to four previously identified copper locations around Laleno Dome.

The findings come ahead of an initial approximately 3,000m campaign combining reverse circulation drilling and diamond tails, scheduled to begin in early September.

Drill Locations Inspected

Estrella collected 11 samples from the five new sites after inspecting planned drill locations targeting high-conductivity anomalies identified by its Mobile Magneto-Telluric drone survey (Mobile MTd).

Three samples came from the interpreted porphyritic intrusion, where visual estimates indicated malachite films on fracture surfaces, although Estrella cautioned that visual observations are not a substitute for laboratory assays.

“These latest observations are a significant step forward in our understanding of the Laleno Dome,” managing director Robert Mencel said.

“Further analytical work will be conducted immediately to confirm our interpretation, but the discovery is nonetheless very pleasing and boosts our confidence in the Dome.”

“Our exploration team are on track with our September schedule, and we will look to test these emerging targets with the deepest mineral-exploration drilling completed in country to-date.”

Hydrothermal Origin Model

Estrella considers the distribution and geological setting of the new occurrences consistent with a possible common hydrothermal origin, although further analytical work is required before that interpretation can be confirmed.

Copper mineralisation observed about 85m and 150m south-southeast of the interpreted porphyritic rock occurs within the Noni Formation, which Estrella considers potentially consistent with mineralising fluids moving into surrounding rocks.

About 3km farther south, weathered ultramafic rock was found to contain quartz-vein stockwork with copper associated with the veinlets, while another sample contained magnetite that Estrella views as additional support for a hydrothermal process.

The 11 samples are being assayed to compare them with samples reported in July and to help determine whether the known copper occurrences share a common origin and whether porphyry-style copper mineralisation may be present.

Drilling and Surveys Advancing

Estrella is preparing three targets for the upcoming RC and diamond-tail campaign, with site preparation expected to finish within two weeks and drilling planned for the first or second week of September.

Ground resistivity and induced polarisation (IP) surveys have been completed across six areas, with processing continuing and additional IP work planned.

A regional helicopter magnetotelluric survey covering Estrella’s broader tenure is scheduled to start in September, with the resulting data expected to complement the Mobile MTd dataset and help generate additional drilling targets.

Assay results from the 11 new samples are expected in late September, while Estrella plans to integrate the assay, drilling and geophysical results as it tests whether surface copper occurrences correspond with larger mineralised bodies at depth.