Surefire Resources has identified nine new drilling targets from reinterpreted IP geophysics data, structural interpretations and re-logging at its Yidby gold project in Western Australia’s Mid West region.
Management says the work significantly complements its understanding of the mineral system and controls on gold mineralisation previously intersected by its drilling and points to potential depth extensions for the porphyry-hosted system.
The company’s fully-owned Yidby gold project sits about 350km north-east of Perth, where it is also following up recently-discovered, broad-scale, coherent copper-zinc anomalism it identified in initial geochemical soil sampling at its Phat Boy target in the contiguous Yidby East ground.
With Phat Boy lying just 50km south along strike from 29Metals’ renowned Golden Grove copper-lead-zinc-gold-silver operation – and with its own demonstrated copper-zinc anomalism and other nearby volcanogenic-hosted massive sulphide deposits north and south of its property in the same belt – Surefire is now ramping up its exploration for possible Golden Grove-style analogues at the target.
The coherent base metal anomalism has been outlined along the margins of an inferred shear zone through a strike distance of about 3km and sits hard up against an outcropping folded banded-iron formation (BIF).
Following a short program of confirmatory follow-up soil sampling, Surefire revealed just over a week ago that it had been granted approval to kick off its proposed 11-hole, 2200m maiden drilling campaign at Phat Boy to test its four most prospective copper anomalies.
Back at the adjacent Yidby gold project, the nine new targets emerged from work undertaken by independent consultants commissioned by the company to review old geophysical data, along with structural interpretations from available diamond-core and from drill-chip relogging.
In 2005, a dipole-dipole induced-polarisation (IP) survey was undertaken by Gindalbie Metals over Yidby. Surefire commissioned geophysical and geological consultants Terra Resources to reinterpret the data, with the goal of identifying potential extensions of gold mineralisation and to pick out new targets. In a possibly serendipitous coincidence, the IP survey had been run over the same area where Surefire discovered gold four years ago.
Terra’s data reprocessing, coupled with 2D and 3D inversion modelling, outlined four high-chargeability anomalies with north-west/south-east trends corresponding to low resistivity zones. When the anomalies are superimposed on Surefire’s 2020 gold discoveries, the mineralisation can be seen to trend along the contact of the high chargeability lens.
A second high chargeability anomaly was noted north of the trend and is believed to be similarly coincident with its north-west/south-east contacts. Additionally, a deeper chargeable zone was noted and will require remodelling to properly define before being incorporated into in the company’s future planning.
The final suite of targets have been assigned as priorities for drilling and all coincide with structural trends identified in examination of diamond drill core.
Structural interpretation of the drill core was undertaken by CSA Global, which was commissioned to review structural data from five diamond drill cores and revealed that two different styles of gold mineralisation are most likely at play. They include gold hosted by quartz veins and stockworks associated with biotite wall-rock alteration and are observed to have two orientations – a north-trending stockwork vein system with high-grade gold mineralisation and a west/north-west-trending system with lower-grade gold mineralisation.
The second style of mineralisation intersected in the diamond core features a felsic porphyry carrying disseminated gold in porphyry-associated quartz-sulphide veining.
Based on structural observations from the drill core and on gold grades, CSA proposed six drill targets, with four high-priority drill locations targeting potential extensions of high-grade gold-bearing quartz veins.
Surefire also commissioned Dr Nigel Maund to re-log selected reverse-circulation (RC) drill chips from the Yidby gold project. He concluded that at least four mineralogically distinct phases of stockwork vein development exist and that porphyry dykes were focal points for more intense stockwork development.
Management says the logging indicates that the local porphyry-hosted stockwork vein system most likely evolved through a succession of early quartz-dominated stages.
Most significantly, the conclusions point to potential for a bigger mineralised system at depth, below the current shallow drilling to date that has not tested below 200m vertical depth. Surefire is now planning a drill program for all of the nine recommended high-priority targets at Yidby and will soon submit a program of works (PoW) for approval.
And with the additional four targets at Phat Boy in the adjacent Yidby East ground, the company is looking at a more extended drilling program that will work through all 13 – and possibly more – targets in a single campaign.
Perhaps, before the rig departs the project, Surefire might have refined its other deeper mystery IP target, too.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Doug Bright
