Rimfire operates a largely contiguous tenement package spanning 915 square kilometres within the East Lachlan Fold Belt (ELFB) of NSW. The ELFB is intersected by the crustal scale Lachlan Transverse Zone with this zone containing most of the world class deposits.
In 2010, the Company delivered a greenfields gold (+ silver) discovery within the Fifield district, named Sorpresa.. A maiden JORC 2012 compliant resource of 6.4Mt @ 0.61g/t Au and 38g/t Ag for 125kOz Au and 7.9Moz Ag was delivered in December 2014. Subsequent exploration has provided evidence that the wider Sorpresa area is now considered a significant gold mineralized district of significant promise.
Sorpresa is comprised of mainly four dominant structurally controlled discrete higher-grade zones of mineralisation referred to as Trench 31, Boundary Gate, Join Up and Roadside within a broader envelope of mineralisation. The mineralisation is present at surface and, at its deepest, point has been defined down dip to approximately 500m, which is 150m to 200m below surface where the primary mineralisation remains open in multiple directions. Mineralisation is dominantly gold with less than 10ppm silver although the Roadside zone is a gold and silver zone.
The maiden Mineral Resource Estimate utilised data from 323 drill holes for a total of 28,898m and is a mixture of high-grade oxide and primary mineralisation.
Additional details can be viewed here.
The gold at Sorpresa occurs dominantly as native free gold formed as ~2 – 50um grains, moderately high fineness. Gold also occurs at Roadside as inclusions in sphalerite or galena or pyrite. Silver mineralisation occurs in galena and tennantite – Tedrahedrite.
There is considerable potential for further discoveries of gold and silver mineralisation within a 6km radius of the Sorpresa discovery. The primary prospects currently under assessment includeNorthern Gold, Rabbers Lookout, Casuarina Valley, Fortuna, Transit and Wiggies.