The Wilandra Corridor is a 75km stretch of the Koonenberry Belt which is prospective for polymetallic mineralisation. The Corridor hosts a number of zones of copper mineralisation which include the largest copper rich massive sulphide zone identified to date in far Western NSW.
A HeliTEM2 (EM) survey was completed over the Wilandra Corridor, identifying high priority targets along its strike. EM results confirm a higher magnitude anomalism along strike, highlighting the potential association with increased sulphide mineralisation. The company sees significant potential in expanding the mineralisation as proven by recent CSAMT and Geochemistry work.
CSAMT Survey
Zonge Engineering and Research Organization Australia (Zonge) conducted field surveys for G11 Resources on the Wilandra prospect, South Australia. Data was collected over fifteen lines and consisted of combined Controlled Source Audio-Frequency Magneto Telluric (CSAMT) and Natural Source Audio-Frequency Magneto Telluric (AMT).
Five CSAMT lines were completed over areas of known copper mineralisation in order to determine a baseline geophysical signature corresponding to established copper mineralisation based on drilling results. This baseline geophysical signature was then applied to the interpretation of the remaining CSAMT survey lines.
These lines were designed as follows:
- To test for geophysical signatures along strike of known mineralisation.
- To test targets parallel to the known mineralisation, featuring anomalous surface geochemistry with coincident HeliTEM geophysical features
The CSAMT survey was successful in both of these aims, and the resulting geophysical signatures on each line will be the target of upcoming drilling campaigns.
Geochemical Survey
A district Scale Geochemical Survey, the first of its scale and extent at Wilandra has been completed with <5000 samples being analysed. The survey was designed to target evidence of mineralisation within the known VMS trends and the geochemical anomalism identified is being applied in conjunction with geophysical survey results to focus and accelerate drilling. Further surveys continue.
Historic Geology/Mineralogy
Massive sulphides in the Wilandra Corridor are hosted by the Grasmere formation. The massive mafic units of the Bittles Tank Volcanics outcrop to the northeast of the deposit.
The sequence hosting the massive sulphide zone includes:
- Thinly bedded metamorphosed carbonaceous shales and siltstones with minor fine grained feldspathic sandstones
- These have been metamorphosed to a quartz–chlorite–brown biotite–pale carbonate assemblage reflecting upper greenschist facies metamorphism.
- Fine-grained, generally foliated, plagioclase–rich mafic rocks with some zones containing remnant roughly aligned plagioclase laths suggesting that some rocks were flow banded basalts.
- These mafic units are now partly to pervasively epidote– carbonate–actinolite altered with chlorite and magnetite
- Un-mineralised breccia zones that include clasts of broken quartz veins/filled fractures fragments, silicified fragments and deformed meta-shale/siltstone fragments/zones.
Distal to the massive sulphide zone, the host rock package preserves a pervasive schistose foliation with only very minor sulphide bearing veinlets present. These veinlets crosscut the penetrative fabric and contain a quartz–adularia–(±chlorite) assemblage with minor pyrite and trace chalcopyrite; they are followed by Fe-carbonate and coarse pyrite; with a final stage of stage of calcite–pyrite–chalcopyrite–sphalerite with rare marcasite. The veins have been boudinaged and deformed by later deformation events.
Mineralised zones are developed within dilational zones/shear zones that crosscut stratigraphy, extending to over 350m below surface. This massive sulphide zone is ~4 km long and offset by later faulting.
Wilandra Copper Corridor – Multi Kilometre Trends
- HeliTEM magnetics displays regional trends of the Koonenberry Belt
- Phased geochemical programs have revealed multi element base and precious metal anomalism
- CSAMT survey has defined structures over 12kms of strike coincident with the widespread metal anomalies
- Geophysics, mapping and geochemistry have defined targets from the initial 4kms to now over 30kms of strike
- Numerous drill ready targets defined in the central and northern parts of the Corridor
- A further 35kms of this Corridor extends to the south, sitting under colluvium and alluvium cover within the broader Koonenberry Belt
- Known mineralisation over
4.5kms within a 75km long belt - Copper-Lead-Zinc-Silver soil anomalies over 30km strike – remains open
- Structures over 12kms of strike with coincident geophysical and geochemical anomalies
- High priority drill targets defined and ready to be tested
- Ongoing structural interpretations and extensional soil programs continue to define further targets
