Estrella Resources (ASX:ESR) reports copper mineralisation in porphyritic rock at its Laleno Dome project in Timor-Leste. Petrographic analysis confirmed hydrothermally altered porphyritic diorite.
The company collected 11 samples from five new sites around the northern part of the dome, with rock chip assays returning up to 0.66% copper (Cu) from outcropping porphyritic intrusive rock.
Sample ESR006494 returned 0.66% Cu at 6,561 parts per million (ppm), while ESR006498 returned 0.53% Cu at 5,334ppm.
Selected rock chip samples from previous work have returned ‘high’ copper values, including 60.34% Cu from ESR006095 and 33.22% from ESR006491. Gold has now been identified at grades up to 1.3 grams per tonne in ESR006492.
Copper mineralisation has been identified at nine locations around the dome. This includes five newly identified occurrences associated with targets generated by the Mobile Magneto-Telluric drone survey.
Petrographic analysis of six samples confirmed the rock texture is consistent with a sub-volcanic intrusive of intermediate composition, containing abundant plagioclase feldspar with minor hornblende and traces of biotite and quartz.
The mineralised rock is a variably porphyritic diorite to microdiorite affected by chlorite-sericite alteration, including quartz-carbonate veinlets and localised silica flooding with patchy disseminated pyrite.
“We have now identified copper mineralisation in porphyritic rock at Laleno Dome, which supports further testing of our geological model for a potential porphyry copper system along the Dome margin,” Managing Director Robert Mencel says.
Geologists investigated about 1.2km north-northwest of the sampled outcrop and found a larger exposure of intrusive igneous rock. Four samples were collected for polished thin-sections, displaying a dioritic composition and texture ranging from fine to medium grained and variably porphyritic.
Estrella’s exploration concept suggests that during the late Miocene, as the main collisional event shaping Timor-Leste waned, magmatic activity coincided with deformation and regional metamorphism.
This intruded diorite and led to magmatic-hydrothermal processes creating porphyry mineralisation within the intrusions.
A regional airborne Magneto-Telluric and Magnetic survey is scheduled for October 2026, with results expected before the end of the year to assist in defining additional drill targets.
The company awaits Timor-Leste Government approval to commence drilling at priority Laleno Dome targets. It is separately planning a 4,000m combined reverse circulation and diamond drilling program at the Sagadate limestone project, subject to approval.
Estrella Resources is an Australian explorer advancing a portfolio of emerging manganese, copper, and critical minerals discoveries.
Write to JC Villarba at Mining.com.au
Images: Estrella Resources
