Kaoko Metals has intersected more than 60 metres of visible copper mineralisation in the second hole drilled at its Chalkos Copper-Silver Project in Namibia and is now drilling a third hole to test whether the mineralisation extends laterally, before two further holes test extensions to the west and south.
The rig will then move to the high-priority Donkey Hill target.
The results come from the first-ever drilling at the 800-square-kilometre Chalkos project, where the first two diamond holes at the Otniel prospect both encountered broad, shallow zones of visible copper mineralisation.
The strongest intersection was recorded in DDOT002, which encountered 60.25 metres of visible copper mineralisation from 36.65 metres to 96.90 metres down-hole, including 32.36 metres of what Kaoko described as strong visible mineralisation from 59.3 metres.
DDOT001 intersected 51.83 metres of visible copper mineralisation from 39.27 metres to 91.10 metres, including a 17.2-metre section of strong visible mineralisation from 58.37 metres.
The company identified several copper minerals in the drill core, including chalcocite, cuprite, malachite, native copper, dioptase and chalcopyrite.
However, the first two holes were drilled from a common drill pad, meaning the intersections do not yet demonstrate how far the mineralisation extends laterally across Otniel. Kaoko said the common location reflected the site’s topography and logistical constraints when drilling started, when earthworks and water access were still being established. Site access has since improved.
Next holes test the extent
DDOT003 is currently in progress and is designed to test the continuity of the mineralisation along strike from the first two holes. It is planned to reach approximately 200 metres.
DDOT004, planned to about 180 metres, will test an extension of the mineralised zone to the west, while the approximately 200-metre DDOT005 will test to the south.
Kaoko is also investigating mobilising an additional diamond rig through Optimine Exploration to support or expand the campaign.
Once the planned Otniel drilling is completed, the current rig is expected to move to Donkey Hill, where Kaoko plans to test high-grade copper mineralisation identified at surface. Project-wide fieldwork will continue at Chalkos to identify further targets for future drilling.
Despite the broad intersections, Kaoko cautioned that visual observations cannot determine the rock’s actual copper grade.
Samples from DDOT001 and DDOT002 are being processed for laboratory analysis, with assays expected within four to six weeks.
The percentages Kaoko quoted for minerals such as malachite and chalcocite are visual estimates of their abundance in drill core sections and are not copper assay grades.
“While it is still early in the program and we are waiting for results of the initial assays, we are pleased to have observed broad zones of copper mineralisation in the first two holes at Otniel,” managing director Gerard O’Donovan said.
“This is a highly encouraging start to the first ever drilling of the 800km2 Chalkos Project, and we are excited to continue drilling at both the Otniel and Donkey Hill prospects.”
Strongest copper in DDOT002
DDOT002 encountered visible copper continuously between 36.65 metres and 96.90 metres across three intervals.
The first 22.65-metre interval, from 36.65 metres to 59.3 metres, was dominated by malachite and cuprite, with Kaoko visually estimating malachite at between 1% and 5% and cuprite at between 1% and 3%.
The strongest section in either of the first two holes occurred between 59.3 metres and 91.66 metres, where 32.36 metres of mineralisation was observed across quartzite, conglomerate and siltstone.
Within parts of this interval, chalcocite and malachite were each visually estimated at between 5% and 8%, while cuprite was generally estimated at between 1% and 3%. Kaoko also identified an interval between 86.4 metres and 91.66 metres containing an estimated 4% native copper alongside malachite and other copper minerals.
A further 5.24 metres of visible mineralisation extended the main zone to 96.90 metres, while another lower-grade copper zone was observed between 107.7 metres and 125.58 metres.
Copper continues deeper in first hole
DDOT001 also encountered copper beyond its main 51.83-metre zone.
A separate 6.51-metre interval was recorded between 102.87 metres and 109.38 metres, followed by another 37.37-metre interval from 125.97 metres to 163.34 metres.
Kaoko said visible copper occurs over a vertical extent of more than 120 metres between its first and last occurrence in DDOT001, although the mineralisation is not continuous throughout that entire distance.
The company also reported trace chalcopyrite within brecciated clasts in DDOT001, which it said indicates primary mineralisation at depth.
Both holes encountered mylonite, a rock produced by intense deformation, close to some of their strongest visible copper mineralisation. DDOT002 recorded mylonitic zones from 59.3 metres to 75.05 metres, while DDOT001 encountered them from about 67.87 metres to 87.15 metres.
The holes also contain fractures, joints and quartz veining.
Kaoko said the association indicates that geological deformation may have helped create pathways for copper-bearing fluids and influenced where copper was deposited.
The copper occurs across several different rock types, including quartzite, conglomerate and siltstone, rather than being restricted to a single sedimentary layer. The company said this provides early evidence that structural controls have influenced copper deposition at Otniel and could mean mineralisation extends beyond individual favourable beds within the broader sedimentary sequence.
The laboratory assays from DDOT001 and DDOT002 are expected within four to six weeks, while drilling will continue at Otniel before the rig moves to Donkey Hill.
