Ruth Well Ni-Cu
The Company entered the Option Agreements on 14 October 2021 to acquire 100% interest in the Ruth Well Project. The Ruth Well Project is covered by four exploration licences and a prospecting licence.
The Ruth Well nickel–copper deposits were discovered by Whim Creek Consolidated in 1971. Mineralisation comprises violaritised pentlandite, pyrrhotite, gersdorffite, niccolite, chalcopyrite, and magnetite within serpentinised extrusive peridotite of the Ruth Well Formation. This association suggests that the deposits are of a similar type to the extrusive Kambalda nickel deposits of the eastern Yilgarn Craton. The mineralisation however probably lies within a tectonic slice of the Andover Intrusion that has been faulted into the Ruth Well Formation of the Roebourne Group on the northern side of the major, approximately 300 km long Sholl Shear Zone.
Figure 1: Local Geology at Ruth Well Project (Source GSWA 1:500,000 Digital geological map with units modified to simplify legend. MGA94 Zone 50 coordinates)
The most significant work to have been completed in the Ruth Well area was by Westfield NL between 1969 and 1975, Titan Resources NL (Titan) between 1989 and 2002 and Fox between 2004 and 2015. These companies carried out a series of open hole percussion, RAB, RC and diamond drilling programs.
Titan completed a TEMPEST AEM survey in 2000 and Fox completed an airborne VTEM HEM survey in 2006. These surveys provided coverage over the broader Ruth Well Project area, however given the high base frequency utilised (25 Hz) these surveys were unable to resolve highly conductive EM targets amongst broader, more extensive stratigraphic/formational conductive units. Fox completed a ground-based SQUID EM survey in 2007.
Previous drilling in and around Ruth Well comprised 426 drill holes including open hole percussion, RAB, RC and diamond drilling for a total of approximately 18,827 metres. Artemis drilled another 37 RC drill holes and one diamond drill hole for an additional 2,923 metres in 2018. Figure 2 shows a cross section of the shallow nickel-copper mineralisation intersected in the Artemis drilling.
Figure 2: Ruth Well Cross Section (looking west). Drill holes colour coded by Ni grade.
Prospectivity and work plan
The intrusion related model for Ruth Well offers exploration opportunities given its proximity and similarity to Radio Hill and Mount Scholl, both known intrusive-hosted Ni sulphide deposits. It is planned that a detailed whole rock geochemical study for major oxide, trace and rare earth elements between fresh rock samples from Ruth Well, Radio Hill and Roebourne Group volcanic rocks to help clarify what magmatic affinity Ruth Well holds with respect to the surrounding mafic-ultramafic lithologies.
Artemis’ geophysical consultants, Southern Geoscience, stated that “broader high-resolution SAM surveying has presented several clear, discrete, shallow level GSEM targets and detailed structural information. Subsequent optimised follow-up FLTEM surveying has been very successful in delineating highly conductive bedrock targets in the vicinity of widespread, historic Ni/Cu sulphide mineralisation and presenting compelling, robust drill targets” (Artemis, 10 April 2018).
A review of a previous VTEM survey has highlighted 7 priority target areas for selective ground geophysical surveys, soil sampling and drill testing. Based on follow-up FLEM surveys three conductor plates have already been modelled associated with these targets. GreenTech will also undertake surface geochemical sampling over the broader project area to assist with identifying anomalous areas for additional geophysical and drill follow up (Figure 3).
As a priority, GreenTech will systematically drill all the priority conductors identified in the FLTEM survey at the Ruth Well project and complete DHEM surveys on all holes to search for potential off-hole conductors. Based on drill success and the ongoing review of Artemis’ geophysical surveys, additional deeper searching FLTEM will be utilised over the larger project area where GSEM has previously identified numerous other targets and trends.
Figure 3: Ruth Well VTEM Targets ranked by priority