Cobra Resources (LSE:COBR), the South Australian exploration and development company, said slim-line reverse circulation drilling at its Manna Hill copper project has extended the Blue Rose mineralised corridor and uncovered two previously undrilled skarn systems.
The first 23 holes of a planned campaign of up to 58 holes, covering roughly 2,000 metres, found broad copper anomalism roughly 600 metres west of known mineralisation, pushing the Blue Rose copper-bearing corridor from about 1.6km to beyond 2.2km in strike.
Drilling also identified copper mineralisation at two new prospects: Shadow Rose, roughly 300 metres south of Blue Rose, where two holes returned up to 60 metres of continuous copper anomalism each, and Neptune Rose, about 500 metres north of Blue Rose, where copper anomalism within the calc-silicate unit confirmed the fold-repeat geological model behind the target.
All three zones remain open, and the company said the programme is ongoing.
Cobra's Manna Hill project, located along the national railway and Barrier Highway between Broken Hill and Adelaide, is a copper-gold skarn and porphyry target where earlier drilling returned high-grade intersections including 74m at 1.02% copper and 0.25 g/t gold from 70m, and deeper results pointing to a larger porphyry system at depth.
The company exercised its option to acquire Manna Hill outright earlier this year, following a four-hole diamond drilling programme that intersected bornite and chalcopyrite associated with porphyry-related intrusions at Blue Rose.
The current assessment is based on visual observations of drill chips and handheld portable X-ray fluorescence (pXRF) readings, which Cobra described as preliminary and qualitative or semi-quantitative, cautioning that no reliance should be placed on them as an indication of grade, tenor or economic significance.
"We are reporting these observations ahead of assays because what they say about the scale of the systems at Manna Hill is potentially material," said Rupert Verco, managing director, adding that "the objective of this campaign is to establish a shallow mineralised footprint of the size required to support a substantial resource, and the early indications are consistent with that."
Laboratory assay results confirming grades are expected in four to six weeks.
A further 14 drillholes are planned at Blue Rose West to test extensions and infill existing drilling, while follow-up work will test strike continuity at Shadow Rose roughly two kilometres to the east.