Estrella Resources Limited (ASX: ESR) has intersected further nickel sulphides in the completion of Phase 3 RC drilling as well as in diamond drilling at depth at the Carr Boyd nickel project, located approximately 80km north of Kalgoorlie in Western Australia.
Phase 3 Above the T5 Discovery
Ten RC holes were drilled above the T5 Discovery Zone to close off mineralisation above an interpreted fault intersected in previous drilling. Most of the holes intersected sulphides on or just above the basal contact. CBP048 intersected 4m of semi-massive sulphides (50%) with visual pentlandite and chalcopyrite.
The company believes that this is the very upper edge of the T5 mineralisation that has been fault-offset 80m to the west. The plunge direction above the fault appears to mirror that of the T5 Discovery mineralisation and strongly suggests (along with previous Phase 3 drilling) that the real potential lies at depth where the sulphide accumulations appear to be thickening.
Managing Director, Chris Daws, said core studies showed this potential to increase in a direction perpendicular to the shallow, south plunge of mineralisation.
I along with the board and management are pleased that the highly successful Phase 3 drilling has now been completed,” Mr Daws said.
“This programme was instrumental not only in intersecting further nickel sulphides but also in providing the company valuable knowledge about the controls on the mineralised zone.
“Phase 4 is set to commence shortly with the objective of conducting step-out drilling to improve Estrella’s understanding of the project’s potential scale as well as identify additional areas of interest which may contain further Carr Boyd style opportunities.
“This is an exciting stage in Estrella’s exploration program at Carr Boyd and I look forward to updating the market as we progress with Phase 4 in further unlocking a world-class, high quality nickel sulphide resource.”
Seismic Targets: Deep Diamond Hole CBDD052 Intersects Remobilised Nickel Sulphide Clasts
Diamond hole CBDD052 targeted a Priority 1 Seismic Survey Anomaly which arose out of a “Point Source Anomaly” of very high acoustic impedance.
This type of anomaly is potentially generated by massive sulphides and lies upon an arc perpendicular to the seismic line. This anomaly has the potential of being generated from the nearby Carr Boyd pipes-style mineralisation. As such, CBDD052 targeted the arc where it intersects the T5 Basal Contact as this is postulated as the most prospective geological target area.
The Basal Contact was hit without the hole intersecting an obvious seismic anomaly. However, the T5 Pyroxenite at depth on the contact was mineralised with rip-up clasts containing nickel-sulphides.
The company interprets that massive sulphides likely formed at depth on the contact.
However, just prior to solidification of the magma, crystal growth and settling enabled the cooling melt to scour the contact clean and remobilise sulphides further “downstream”. This was discovered in the close-spaced Phase 3 drilling, particularly at the leading edge of the T5 mineralisation where similar scouring was identified.
The remaining seismic targets will be addressed by further exploration drilling in due-course. However, the T5 mineralisation and Basal Contact (where the vast majority of economic Intrusive-style nickel is found) remains the priority for Phase 4. Holes will be set aside in Phase 5 to test the extensive seismic targets.
Downhole Electromagnetics (DHEM) was performed on CBDD052 leading to the generation of off-hole anomalies relating to the known Carr Boyd mine.
A large anomaly (300m x 300m off-hole DTEM plate) below and to the north was identified which the company believes is either related to a footwall sedimentary sequence or potentially an embayment or trap-site of massive sulphides that lies below the basal contact. The company has completed a pre-collar and will test the large off-hole DHTEM plate and basal contact area at depth shortly with CBDD056.
Deep Diamond Hole CBDD056 CBDD056 will be drilled to test the T5 Basal Contact 200m to the north of the CBDD052 position where sulphides may have accumulated on the contact. This position also coincides with the projected plunge of the T5 Mineralisation.
Phase 4 100m North and South Step-out Sections at T5 A series of RC pre-collared DHEM platform holes and wedged daughter holes are being collared to enable the company to incrementally grow the T5 mineralised zone.
The close-spaced Phase 3 drilling enabled the Company to understand the many controls on mineralisation and also the variable DHEM responses generated from known mineralisation which failed to give an EM anomaly.
These learnings and drill techniques will be used to increase the size of the T5 Zone in combination with additional DHEM and the Seismic Survey so as to accurately target the Basal Contact, known plunge direction and also test for further, parallel lodes generated by the perpendicular flow direction.
The RC portion of this phase has already commenced and the diamond tails and DHEM will be completed after the drilling of CBDD056.