Impact Minerals (ASX: IPT) is fast tracking exploration to identify drill targets at its Apsley prospect in New South Wales’ Lachlan Fold Belt after new data has pointed to the potential for a “very large” porphyry copper-gold complex.
According to the company, new soil geochemistry and airborne magnetic data from the prospect, located within its wholly-owned Commonwealth project, have defined “near-textbook” examples of the zonation expected around major alkalic porphyry copper-gold complexes.
The zones are defined over an area of about 5sq km and three priority areas have been highlighted for follow-up work.
Zones of similar scale to world-class PNG copper-gold deposit
A highlight of the data included a core 2,000m by 500m zone of anomalous gold-copper-palladium-platinum, interpreted to lie within a “zinc doughnut” defined by a very large outer halo of anomalous zinc-lead-manganese covering at least 3sq km.
Such doughnuts are characteristic of major porphyry copper-gold deposits and attests to the “very large scale” of the alteration system present at Apsley, Impact reported.
Furthermore, within the outer halo are two more areas, each about 1sq km in size, that contain variably overlapping, discrete zones of metal assemblages related to the lower phyllic, upper phyllic and advanced argillic zones expected around and above porphyry deposits.
The company particularly compared the scale of the combined zones to that at Newcrest Mining’s (ASX: NCM) world-class Wafi-Golpu deposit in Papua New Guinea, which is also characterised by a “textbook” zinc doughnut.
Alternatively, Impact said the zones may represent parts of one very large porphyry system that has been broken up by later faulting and is also common globally.
Fast tracked exploration program
Impact managing director Dr Mike Jones said the results have “far exceeded” the company’s expectations.
“The zonation we see, in particular the gold-copper-palladium-platinum association so characteristic of alkalic systems like Cadia and North Parkes, is almost textbook in nature and we now need to define specific targets using IP (induced polarisation),” he added.
The IP ground geophysical survey will help identify zones of disseminated sulphide at depth that may represent ore zones. It will focus on the three priority areas identified as potential centres of porphyry copper deposits.
Impact said the survey is scheduled to start at the end of August with results anticipated by the end of September.
“Any targets identified will be fast tracked for drilling as quickly as practicable,” Dr Jones said.