Kaoko Metals has expanded drilling at the Otniel prospect in Namibia to at least 15,000 metres after its first holes encountered broad zones of visual copper mineralisation, while a second diamond rig has started drilling at Donkey Hill after discovering additional surface copper mineralisation.
The two-pronged programme means Kaoko is now drilling the two prospects at its Chalkos Copper-Silver Project concurrently, with five diamond holes completed at Otniel and a sixth, DDOT006, in progress.
The expansion at Otniel comes before laboratory assays from the first two holes, DDOT001 and DDOT002, which Kaoko expects within two to three weeks.
Kaoko said the decision to increase drilling to at least 15,000m was underpinned by the visual copper mineralisation encountered in those first two holes and the need to systematically determine the geometry, continuity and extent of the mineralised system.
All holes drilled to date have reached their planned depths, and the company is progressively submitting samples for laboratory analysis, seeking expedited assay turnaround across the programme.
At Donkey Hill, meanwhile, new fieldwork has extended the known surface copper mineralisation by more than 700 metres, taking the total mapped surface expression to more than 1.5 kilometres.
One selected rock-chip sample, Z2516, returned more than 50% copper, exceeding the assay method’s upper reporting limit.
Kaoko cautioned that the rock-chip results are from selected surface samples and are not representative of the average grade of mineralisation across the mapped footprint. They should also not be interpreted as evidence of subsurface grade or continuity.
The expanded Otniel programme will test both down-dip continuity and lateral extensions of the known mineralisation.
Kaoko said the drilling is intended to progressively establish the three-dimensional geometry of the mineralised system, including its orientation, thickness, structural controls and continuity beyond the areas tested by the initial holes.
Managing director Gerard O’Donovan said the initial drilling had provided the basis for increasing the programme.
“The expansion of our drilling program at Otniel to at least 15,000 metres reflects the outstanding progress from our initial drilling campaign and the opportunity to systematically test the mineralisation identified to date,” he said.
“At Otniel, five holes have now been completed to evaluate the geometry and continuity of the mineralised system, with each hole utilised to refine subsequent drill targeting. We are also working closely with the laboratory to expedite assay results for all holes completed to date so that we can communicate technical results to the market as soon as possible.”
Kaoko’s earlier announcement on 2 September confirmed that its first two Chalkos holes had encountered broad zones of visual copper mineralisation. The company cautioned at the time that visual observations cannot substitute for laboratory assays to establish copper grades.
While drilling continues at Otniel, Kaoko has mobilised a second diamond rig to Donkey Hill, where drilling commenced this week.
New fieldwork at Donkey Hill East has extended the mapped surface copper mineralisation by more than 700m beyond the initial 800m footprint Kaoko reported in July.
Kaoko said Donkey Hill’s total mapped surface expression now exceeds 1.5km.
At Donkey Hill East, mineralisation has been traced along two trends extending approximately 600m and 400m respectively.
Recent fieldwork has also identified stockwork copper veining within laterally extensive quartz arkose units, relict sulphide mineralisation now expressed at surface as pitting and malachite following oxidation, and dioptase mineralisation filling cavities and joint planes.
Kaoko said the combination of stockwork veining, relict sulphide textures and cavity-infill dioptase points to structural and hydrothermal controls operating across a broad area.
“The discovery of significant additional surface copper mineralisation at Donkey Hill East is a particularly encouraging development as it expands the potential scale of the mineralised system,” O’Donovan said.
“This development reinforces Donkey Hill as an important exploration target within the broader Chalkos Project.”
Kaoko’s managing director and chief geologist are expected on site from next week to oversee the next phase of drilling.
The company now has two active drilling fronts at Chalkos: an expanded programme of at least 15,000m at Otniel and newly commenced drilling at Donkey Hill.
The immediate milestone at Otniel will be the laboratory assays from DDOT001 and DDOT002, expected within two to three weeks, while drilling at Donkey Hill will begin testing whether the copper mineralisation mapped at the surface continues below ground.
