Cohiba Minerals gets back to drilling at Horse Well Copper Prospect after wet weather delays, South Australia

Cohiba Minerals (ASX:CHK) reports drillhole HWDD08 has been completed to a depth of 1,509.9m following a 3 week delay due to flooding at the Horse Well Copper Prospect in South Australia.

The company says it is preparing samples for assaying, and assay results for HWDD01 and HWDD02 are expected soon along with the infill assay results for PSDDH01 where Cohiba is following up on the anomalous zinc, lead and silver results reported in July.

It has also submitted 474 samples from hole HWDD07 drilled from July to September at Horse Well located within the Olympic Domain for assay. 

Cohiba Minerals CEO Andrew Graham said the Horse Well Prospect remains a priority exploration area for Cohiba with multiple IOGC target zones being identified.

“We are committed to investigating it to the fullest extent possible and applying the best technical rigour to maximise the likelihood of exploration success.

“We are committed to investigating it to the fullest extent possible and applying the best technical rigour to maximise the likelihood of exploration success”

We have identified some significant structures and IOCG characteristics with persistent low-level copper mineralisation across significant strike lengths.

We have also spent considerable time reviewing the geophysics data to further assist our drillhole target selection process. We are building a solid IOCG story in the Horse Well Prospect and are confident of further good results.”

Cohiba reports hole HWDD07 reached basement at 930.35m and was completed to a total depth of 1,519m targeting the southern extension of the Blue Bush Fault previously identified in holes HWDD05, HWDD05 and HWDD05W1, aiming to gain further confidence in the exact orientation of the fault and to test the strike extensions to the south in a region of magnetic low.

The identification  of the Blue Bush Fault as a structure of interest came about while mapping strip logs of the previous drilling, and holes HWDD04, HWDD005, and HWDD05W1 had generated interest due to broad zones of copper mineralisation generally in the form of quartz-magnetite-chalcopyrite-pyrite veining.

In each of these holes, the company says ‘significant’ fault features were found, and although the presentation of the fault is different from hole to hole, the faults were presumed to be the same fault based on a ‘unique’ orientation to the fault and fault features over 30cm at Horse Well tend to be rare and as a result related to pervasive structures.

The company says although 3 intersection points were identified, there still remains a variety of possible orientations consistent with the data, and the intersection of the Blue Bush Fault at the predicted location is a ‘strong’ indication that the fault actually exists and will enable further more aggressive step-out drilling.

Cohiba considers the Blue Bush Fault was considered to have IOGC affinity based on brown earth and grey hematite matrix breccia with disseminated chalcopyrite identified in HWDD05, the oxidation of magnetite to hematite in HWDD05, crackle and clast supported breccia in HWDD05 and HWDD04, crackle breccia with siderite-disseminated chalcopyrite-pyrite seen in HWDD04 and patchy elevation of lanthanum and cerium in all holes.

Additionally ‘very high’ supergene gold and silver were encountered at the basement contact in holes HWDD04 and HWDD05, which the company considered a ‘good’ indicator for mineralisation.

It notes hole HWDD04 intersected 1.1m @ 4.79ppm Au and 3.51ppm Ag from 948.21m to 949.31m, and hole HWDD05 intercepted 2m @ 5.2ppm Au and 1.05ppm Ag from 928m to 930m.

Cohiba reports HWDD07 intersected the Blue Brush Fault slightly higher in the hole than the north to south strike orientation predicted and the strike of the fault was revised to 020º, and individual readings on the upper Blue Bush fault gave dip directions of 270 degrees still indicating north to south strike orientation but with a jog.

It says reconciling readings at a core scale with the large scale orientation of a major fault will always be a challenge and will limit the extend that any step-out drilling can be conducted without real risk of missing the target entirely, however the strike orientation is distinct enough from other rock features to be confident they are related to the Blue Bush Fault.

Dips of 60 degrees to 70 degrees are consistent with those expected from previous drilling, and orientation on the Lower Blue Bush Fault was not possible as linear features are not present, however the fault style was consistent enough with HWDD04 to correlate these 2 features.

The company states Blue Bush has low level IOCG affinity and IOCG mineralisation which is considered both uncommon as a regional alteration and has the potential to expand into ‘significant’ mineralisation if a positive feedback loop or structural preparation and fluid flow is present.

A possible structural controlled IOCG is envisaged, as occurs in IOCG deposits in South America and the Cloncurry block, and constraint to a structure bound feature may also promote ‘higher grades’ as seen at Prominent Hill where the mineralised horizon is restricted by strata, as opposed to a non-focused breccia pipe overprinting a granite.

This may increase the economic potential for mining, despite the increased depth although it remains a hindrance for exploration.

The company says the current model is to expand exploration to the south into the magnetic low area, following the model that oxidising ground waters will convert magnetite to hematite.

Cohiba will also be searching for a 2 fluid system of oxidising ground waters and less oxidising deep seated magmatic fluid mixing as a precursor for IOCG, and drilling should be centred on 400m spaced step-outs, however this will need to be planned around confidently hitting the target.

Exploration to the north, into the magnetic high area is not precluded, following the Prominent Hill model where ‘significant’ magnetite is introduced into the system.

Cohiba Minerals is an ASX-listed development company with a focus on investing in the resource sector through tenement acquisition, joint ventures, farm in arrangements and new project generation.

The company has projects located in South Australia, Western Australia and Queensland with a key focus on its Olympic Domain tenements located in South Australia.

Images: Cohiba Minerals Ltd
Written By Harry Mulholland
Hailing from the Central Coast region of NSW, Harry is a passionate journalist with a background in print, radio and ESG news. When not bashing away on his keyboard, he can be found brewing a coffee or playing with his dog.