Cobra Resources (LSE:COBR), a South Australian mineral exploration and development company, has exercised its option to acquire the Manna Hill copper project following encouraging results from a four-hole diamond drilling programme.
The company secured the option last August, and the decision to trigger it now rests on geological observations from 1,465 metres of core drilling designed to test extensions of shallow, high-grade mineralisation at the Blue Rose prospect.
Drill hole MHDD002 found chalcopyrite from 169m to 209m, consistent with earlier reverse circulation results, and bornite mineralisation from 220m to 257m within a schist enveloping porphyry intrusions.
Bornite, a high copper-to-iron sulphide that forms at elevated temperatures, is associated with the potassic zones of porphyry systems and here coincides with a modelled magnetic anomaly, giving Cobra a direct geophysical vector for further targeting.
A separate hole, MHDD003, intersected a large fault-bound anhydrite breccia zone between 190m and 220m, interpreted as a structural pathway linking a parent porphyry to the Blue Rose skarn.
"Intersecting a bornite-rich zone associated with a porphyry intrusive sequence is a positive indicator of a potentially higher-grade porphyry system," said Rupert Verco, Cobra's managing director.
Assay results are expected starting next month, with follow-up reverse circulation drilling targeting further magnetic and skarn extensions planned for September.
