Encounter Resources Ltd (ASX:ENR) has refined targets for drilling to commence in April 2023 with geophysical modelling at the Aileron Cu-REE project (100% ENR) in the West Arunta region of WA.
Encounter has completed major gravity, magnetics and radiometric surveys at Aileron. These surveys have defined three priority drill targets,” Managing Director, Will Robinson, said.
“The Crean, Worsley and Caird targets are exceptional, large scale magnetic and gravity anomalies in an unexplored emerging critical minerals province.
These anomalies have similar geophysical characteristics to the IOCG deposits in South Australia, such as Prominent Hill, and the recently discovered mineralised carbonatites in the West Arunta. The drill targets have been modelled as sub-vertical features at explorable depth. Diamond drilling will commence in April 2023.”
Background
Aileron is located in the West Arunta region of WA ~600km west of Alice Springs. To date, only one diamond hole, EAL001, has been drilled within the project which targeted a discrete magnetic anomaly at the Worsley target. EAL001 was partially completed to a depth of 158m and drilled through 5m of shallow cover followed by a brecciated hydrothermal hematite-chlorite-altered granite with a narrow mafic intrusion.
Assays from EAL001 include zones of anomalism in copper (up to 0.1% Cu), gold (up to 48ppb Au), molybdenum (up to 155ppm Mo), niobium (up to 773ppm Nb) and highly elevated rare earth elements (up to 0.8% TREO) consistent with the IOCG deposit model.
The presence of highly anomalous copper-gold-REE in the first hole at Aileron and the recent mineralised carbonatite discoveries by WA1 indicate that an alkaline magmatic hydrothermal system has been active in the region. Such systems are known to play an important role in the formation of both IOCG and carbonatite-hosted REE deposits.
Encounter completed large gravity, magnetic and radiometric surveys at Aileron during 2021 and 2022. These surveys have defined three priority drill targets for 2023: Caird, Crean and Worsley.
Caird
Caird is a ‘bullseye’ coincident magnetic and density anomaly on the Endurance fault, five km north- west of WA1’s recent mineralised carbonatite discovery at Luni.
Geological reconnaissance noted that the gravity high was covered by aeolian sand and was surrounded by a semi-circular series of low lying ferruginous duricrust hills.
Gravity and magnetic modelling have defined the first hole to test Caird. Additional drill sites have been heritage cleared for follow up drilling.
Crean
Crean is a regional scale magnetic anomaly at a key structural location on the major Elephant Island fault which has an offset gravity anomaly, a similar geophysical footprint to the Prominent Hill IOCG deposit in South Australia.
Two holes will be drilled to test both the magnetic and gravity anomalies at this target.
Worsley
Worsley is the region’s standout magnetic and coincident gravity anomaly. The upcoming diamond drill program will extend drill hole EAL0001 that was terminated at a depth of 158m without testing the magnetic-gravity anomalies. EAL0001 was ineffective and ended prior to designed depth due to a mechanical failure on the drill rig. Assay results later confirmed highly anomalous Cu, Au, Mo, Nb and REE (up to 0.8%) in the top of the hole.
Upcoming Activity
Diamond drilling at Caird, Crean and Worsley will commence in April 2023.
In addition, a track will be established to the Shackleton target located ~12km west of Caird. Shackleton is a gravity anomaly over which no outcrop was identified during geological reconnaissance. In the northern part of Shackleton there is a low lying quartzite outcrop, containing iron alteration where a single reconnaissance rock chip sample of the iron rich material returned 0.5% REE. Geological mapping and systematic geochemical sampling are planned at Shackleton in April-June 2023.
A 3,300 line km airborne Falcon gravity survey will be completed in May 2023 to extend detailed gravity over the entire project. This 300m spaced survey will be a fundamental dataset for the targeting of IOCG and carbonatite-hosted REE deposits in the West Arunta.