Detailed geophysical magnetic and gravity survey results acquired to date are high quality and show detailed information that will be used for target selection to identify other potential mafic-ultramafic intrusions.
Figure 1: Regional gravity image showing the extension of the important gravity corridor into the company's tenure, Albany-Fraser Range Province.
Many such targets have been identified from the geophysical data and remain to be tested (Figure 2). Of the limited number tested so far, three have identified magmatic nickel-copper sulphides hosted in varitextured mafic-ultramafic intrusive bodies with geochemical signatures characteristic of the other intrusive suites identified elsewhere within the Fraser Zone that host magmatic nickel-copper sulphides, including Nova. These data sets offer a powerful first pass prioritisation tool for exploration for this type of deposit.
Each of the targets will be progressively field checked with an appropriate combination of air core and diamond drilling and deep penetration ground electromagnetic surveys. The company is utilising ground based high-powered moving and fixed loop electromagnetic surveys, as well as borehole electromagnetic surveys, over high priority targets as this represents the best proven technique to detect magmatic nickel-copper sulphide accumulations.
While maintaining primary focus on the core nickel-copper sulphide potential, the area is also considered prospective for Broken Hill-type Lead-Zinc deposits, and although of a lesser priority exploration should remain opportunistic to gold. The regional gneissic country rock sequences that host the mafic-ultramafic intrusive bodies share many similarities with terranes around the world that host Broken Hill style mineralisation. Base metal prospectivity is interpreted to be greatest at the transition from magnetically complicated areas to areas that are magnetically quiescent on the flanks of the central gravity high feature, as this may represent the transition from active rifting to sag-phase sedimentation analogous to the Broken Hill orebody setting in NSW. Exploration activity will test this prospectivity alongside the high-priority nickel-copper sulphide exploration program.