It said four reverse circulation drill holes had been assayed, showing mineralisation was open in multiple directions (to the north, east and west) from the surface.
The intersections included 20m at 1.31% copper equivalent (0.25% copper and 0.097% cobalt); 25m at 1.24% CuEq (0.48% Cu and 0.062% Co); 26m at 1.1% CuEq (0.31% Cu and 0.072% Co) and 27m at 0.84% CuEq (0.28% Cu and 0.051% Co).
Arc executive chairman Nick von Schirnding said the early results "clearly demonstrate the large tonnage and commercial grade potential of the Kalaba prospect".
Arc has so far completed 14 RC holes for more than 1,000m.
It has also completed 19 diamond drill holes over 2,800m and expects those assay results soon.
The overall drilling programme aims to show large scale potential at Kalaba and includes a total 4,400m of diamond and 6,600m of RC drilling.
Arc's shares slipped 0.52% after the news Tuesday to 4.92p (US6.4c).
