This is the first drill hole designed to test one of several SkyTEMTM geophysical anomalies identified within the Okiep Project
Locality of Targets 3 (right) and 4 (left) SkyTEMTM anomalies on Nous Prospect outside Nababeep. (Credit: Orion Minerals Limited)
Orion Minerals Limited (ASX/JSE: ORN) (Orion or Company) is pleased to advise that it has made a significant new copper discovery within its Okiep Copper Project in the Northern Cape Province of South Africa (Okiep Copper Project).
The first diamond drill hole completed to test a coincident magnetic and electromagnetic (EM) anomaly at the Nous Prospect has intersected mafic-intrusive-hosted copper sulphide mineralisation over a drill width of 10m from 31.72m down-hole in drill hole OND001.
This is the first drill hole designed to test one of several SkyTEMTM geophysical anomalies identified within the Okiep Project from an extensive SkyTEMTM survey flown last year.
The mineralisation intersected occurs as blebs, veins and massive sulphide (80-100%) lenses of pyrrhotite–chalcopyrite over widths of 1-25cm in drill core within the magnetite rich, mafic intrusive host (see Figure 1 below).
Orion’s Managing Director and CEO, Errol Smart, commented:
“This exciting discovery at the Nous Prospect provides early validation of our exploration methodology for the Okiep district. Remarkably, this is the first discovery in the district in more than forty years – and it is directly attributable to the use of modern geophysics, followed by mapping and detailed ground surveys.
“Our early exploration success underscores the huge potential upside in the Okiep region, where geological records and mining history show that many orebodies either have no outcrop or have only minor showings at surface, as in this case.
“The significant chalcopyrite-pyrrhotite mineralisation intersected in the hole is exactly what we had targeted with the SkyTEMTM survey. From the historic records, we know that the predominant copper mineralisation in the district is bornite and magnetite-rich and will therefore, not respond well to EM detection. However, we also recognised that all of the largest bodies that were mined at Okiep had recorded the presence of pods of pyrrhotite rich sulphides, which will react strongly to EM survey techniques.
“The value of modern EM surveying, which allows us to more accurately model the depth of targets is demonstrated by the fact that Newmont’s Okiep Copper Company had identified this magnetic target and tested it with a 104.85m deep vertical drill hole, which was stopped above the EM target that we have modelled as commencing from a depth of 290m at Target 3.
“Targets 3 and 4 have now been re-ranked by Orion to top priority and fast tracked for drilling due to the discovery of copper oxides at Target 4, together with other key structural and alteration indicators on surface over the entire Nous Prospect area.
“What is really exciting, however, is that a further eight selected high priority SkyTEMTM targets are currently being followed up with systematic ground surveys at the Okiep Copper Project and will be drilled over the next 12-24 months. The potential for new discoveries and significant additions to what is already an area with enormous copper endowment, is huge.”
The mineralisation was drilled down dip of an outcrop of mafic rocks partly obscured by gneiss scree with of green and blue copper oxide staining. The outcrop is located in a steep gully, in rocky, mountainous terrain incised by deep crags (Figure 3). The dominant outcrop in the area is the host Nababeep Gneiss country rock with small inliers of ferruginous schist and meta-quartzite.
The Nous Prospect was initially selected for follow up after two relatively strong EM conductors contained within a large magnetic anomaly were identified by the SkyTEMTM helicopter borne EM survey completed in September 2021 (refer ASX/JSE release 28 October 2021).
Historic records show that Newmont had also identified a magnetic anomaly at this site, three shallow vertical holes (ranging in depth from 104.8m to 238.0m) were drilled by Newmont, with no intersections of mafic rocks or mineralisation were recorded in the holes and no copper mineralisation was mapped in the prospecting area.
The SkyTEMTM geophysical data has been supplemented by high resolution drone magnetics and ground gravity surveys, all of which revealed coincident anomalies over the same target area (Figure 5). The two SkyTEMTM EM targets have cores located 570m apart and are modelled at 290 – 510m depth at Target 3 and 70 – 237m at Target 4 (Figure 6).
Source: Company Press Release