ASX- and JSE-listed Orion Minerals’ analytical results for the Ayoba prospect, which is 5.3 km from its flagship Prieska project, have confirmed the discovery of a new volcanogenic massive sulphide (VMS) zinc/copper-bearing body.
The new mineralisation find validated Orion’s expectation that there is potential to discover a cluster of VMS deposits around the Prieska project.
Ayoba’s drilling intersected 9.5 m at 0.93% zinc, 0.63% copper, 0.22 g/t gold and 2 g/t silver from a down-hole depth of 654 m.
The mineralisation included a high-grade zone of 1.5 m grading 4.98% zinc, 0.89% copper, 0.26% gold and 3 g/t silver, from a down-hole depth of 654.5 m.
The discovery came at a time when Orion’s near-mine exploration programme continued to ramp up, with the completion, in December, of a helicopter-borne magnetic and electromagnetic suvery over the prospecting rights of the Repli, Doonies Pan, Vadocube and Bartorax areas, all situated in the Northern Cape.
The Ayoba discovery hole marked the first hole to be tested for new mineralisation surrounding the historical Prieska copper mine in more than 36 years. It was also the first hole to be drilled as part of the company’s near-mine exploration programme.
The Prieska project’s mineral resource estimate currently stands at 30-million tonnes, grading 3.7% zinc and 1.2% copper.
Orion reported that historical exploration in the area had stopped prematurely after the discovery of the Annex deposit, which is 1.6 km to the east of Prieska, which had a best intersection of 4.28 m at 0.34% zinc and 2.88% copper, drilled in 1979.
The company on Wednesday stated that the current structural interpretation of the drilling results showed that the newly discovered mineralisation, as well as the Annex and Prieska deposits, occur on the same stratigraphic horizon.
“This conforms to Orion’s exploration model of VMS deposits clustering around giant VMS deposits such as the Prieska deposit, to form VMS camps,” the company said.
The company has planned additional surveys and drilling to explore the lateral and depth extensions of the mineralisation.
Further, Orion will prioritise the found anomalies and integrate them with existing geological data, and do detailed field mapping to confirm the geological setting – taking into account the characteristics of VMS deposits, including spatial association with the paleo-seafloor, presence of alteration and structural setting.