Pathfinder Exploration Techniques Targeting Porphyry and Epithermal Alteration SystemsiIn the Temora Copper-Gold Belt

Abstract

The Temora project is a key exploration target for Sandfire to discover an economic copper-gold deposit in the Lachlan Fold Belt, NSW. The district contains an Ordovician Volcanic centre that has been explored over many years and hosts a number of defined porphyry and epithermal deposits. The availability of historical drill holes meant pulps could be re-analysed for multi element geochemical data and Short Wave Infrared analysis (SWIR) data to be collected across the district. Spectral data from the white micas defined the areas of higher temperature alteration associated with mineralisation across the district. Analysis, logging and re-interpretation of the data led to the definition of a number of new targets where the systems were poorly or untested. A high priority target was defined at the Donnington prospect to the north of a small known porphyry resource on the margins of the Rain Hill intrusive complex. The target showed a potential porphyry zonation systems in the interpreted geology, alteration, SWIR analysis, geochemistry and geophysics. Drilling in the first field season intersected 120m @ 0.3 % Cu and 0.5 g/t Au from 250m with follow up drilling intersecting 77m @ 0.3 % Cu and 0.5 g/t Au from 250m around a small porphyry intrusive. Mineralisation is hosted in quartz-magnetite-feldspar-pyrite-chalcopyrite veins associated with a chlorite-magnetite-carbonate alteration. A later quartz-sericite-pyrite alteration postdates the mineralisation causing a demagnetised zone surrounding a weak magnetic high that has been used in defining the mineralisation. The mineralisation is still open and further drilling is required.