Intrusive Related Gold
Fine grained, variably weathered monzonite
“Gold discoveries associated with felsic to intermediate intrusions (as evidenced by the recent De Grey Mining Hemi discovery) are gaining significant momentum within Western Australia. The Warriedar West project is well placed towards targeting such systems and maximising their economic potential.”
– Dr Anthony Morey, Technical Advisor
The Warriedar West Project is an outstanding gold exploration project with high grade gold discovered within a 15km x 3km altered target zone. The project is located within the Murchison region of Western Australia only 4 hours north of Perth.
The area was previously considered to be ‘barren granite’ and was consequently ignored by many explorers – despite the fact that the area has been a prolific source of gold for the prospecting community over the past thirty years. Through fieldwork conducted over the past two years Tempest has identified that the project represents a section of a larger ‘intrusion related gold system’. Rock chips from the project have yielded up to 8gpt gold and in April 2020, Tempest announced initial surface geochemistry results indicating large polymetallic anomalies within this target zone.
Historical gold production for the Warriedar Mining Centre over the period 1913-1935 was 148 kg recovered from 13,900t of ore at an average grade of 10.7g/t Au. Ore was processed at the numerous state batteries that operated in the region, one of which operated at Warriedar until ~1940.
The Warriedar region has a history of base metal production with the Warriedar Mine producing copper between 1958-1969 at a grade of 9.83% Cu.
The historical mining on the Warriedar Goldfield was undertaken by syndicates on a campaign basis with limited access to capital.
In more modern times, prospectors have gleaned gold from the Warriedar Project area through dry blowing and artisanal workings. This activity drew the interest of Tempest Minerals who have been conducting exploration campaigns since 2016 studying the source of this gold.
“The Warriedar Project is a fascinating gold bearing system previously not well defined. We are very excited about progressing the Warriedar West Project.”
– Don Smith, Managing Director
The Warriedar West prospect is a zone of porphyritic monzonite – the Walganna Suite which is a highly argillic to potassic altered fine grained, weathered intrusion with intermittent intense shearing and silicification. Within the Walganna are a number of known sources of gold mineralization including in-situ primary quartz veins, shear zones, laterites and alluvial gold.
The geological model indicated by the evidence at the Warriedar Project places the mineralisation in that of an Intrusion Related Gold System (IRGS). Due to the relatively new classification IRGS are not widely explored for, though this is changing. Many contemporary examples of this kind of deposit include the Timbarra4 deposit in northern New South Wales (0.5Moz Au), Kidston in northern Queensland (5.3Moz Au) and the high profile Northern Star Resources Pogo Mine (10Moz Au) in Alaska.
These types of deposits are often hosted within small plutons like the host rock at Warriedar (the Walganna Suite) and are typified by an array of sheeted quartz veins with associated argillic and sericitic alteration halos. Another definitive feature of many IRG systems is the affinity to certain trace elements such as Arsenic, Antimony and Tungsten. Several multi-square-kilometer anomalous areas are visible at Warriedar for a number of these indicator elements.