HWDD03 Technical Review
Melbourne, May 8, 2023 AEST (ABN Newswire) - Cohiba Minerals Limited (ASX:CHK) (CHKMF:OTCMKTS) is pleased to announce the results of the detailed technical review completed for HWDD03 drilled at the Horse Well Prospect (Figure 1*).
- HWDD03 has sufficient indicators for proximity to an IOCG system to warrant further investigation.
- IOCG indicators include a HEMQ altered fault, the presence of disseminated chalcopyrite, and extensive chlorite alteration.
- HWDD03 adds to the Bluebush Fault Prospect and Horse Well Fault Prospect for a total of three prospective sites from the initial five locations selected for grass-roots drilling at Horse Well tenements.
HWDD03 completed drilling in October 2020.
HWDD03 was drilled on Horse Well prospect from 12 September 2020 to 22 October 2020 to a total depth of 1179.7m. The target was the magnetic portion of a coincident residual magnetic - gravity high (Figure 2*).
The drill hole is 4.5 kilometres east of BHP's Oak Dam IOCG (Iron Ore Copper Gold) deposit. Initial logging of HWDD03 combined with the open gravity high portion of the geophysical target led to the follow up hole of HWDD06 (completed as HWDD06W1). This hole was poorly altered and mineralised, however it appears to have been drilled immediately south of the Horse Well Fault, discovered in subsequent drill hole HWDD08 with +600m of vertical throw. The diorite dyke at the base on HWDD06W1 matches the orientation and expected extent of the Horse Well Fault. This leaves the residual gravity high largely untested.
HWDD03 reached basement at 989.6m and intersected Donington Granite and a pre-Donington Gneiss that both share the same foliation history (Figure 8*). A pervasive minor sericite alteration was overprinted by red feldspars carrying minor copper mineralisation in the form of disseminated chalcopyrite (and accessory pyrite) (Figure 4*), particularly strongly adjacent to the granite-gneiss contact. At 1044m is a 2m (true thickness) fault of reddish-brown hematite-silica infill, carrying clasts of white quartz and with a weak sericite overprint (Figure 5, Figure 6*). This mineralogy is typical of barren HEMQ which is commonly the core alteration zone of a mature IOCG system. Chlorite alteration which is texturally destructive of the prior alterations (Figure 7*) and mineralisation is predominant in the granite and an east dipping fault at the base of the hole (Figure 9*). The chlorite is inferred to be an outer alteration halo to the faults but may be a more widespread feature.
The barren HEMQ fault is enigmatic in that this alteration is generally found in the central portion of an IOCG breccia system immediately adjacent to the high-grade chalcocite zone. The recognition of barren HEMQ has been of importance in the discoveries of IOCG systems. It is possible that this fault controlled HEMQ has similar geometry to the stratiform HEMQ at Prominent Hill mine, implying that parts of this fault may be layered with mineralisation.
Disseminated copper mineralisation such as chalcopyrite is rarely observed in the Olympic Domain outside of the IOCG environment, and at Horse Well tenements has nearly always been accompanied by brecciation, and evidence for IOCG preparation. In contrast vein style mineralisation may be widespread.
Substantial chlorite alteration is not observed in the other Horse Well holes (outside of the paleo-weathering horizon). Strong chlorite is one of the alteration styles commonly encountered on the margins of IOCG systems.
Taken in conjunction these three items support the proximity to an IOCG system, and further exploration work is warranted.
Previous selected sampling of HWDD03 returned low assay results. Resampling was conducted to better cover the mineralised areas and give generally more coverage of the hole. Awaiting assay results.
Cohiba's CEO, Andrew Graham says, "The Horse Well Prospect now comprises three significant IOCG target zones which we are committed to investigating to the fullest extent possible. Due to the depth and complexity of these environments we have spent considerable time ensuring that we extract as much information out of the drilling data as possible. This technical report provides further evidence of the technical rigour applied to our exploration efforts as we seek to make a major IOCG discovery. The results to date are highly encouraging and we remain confident that our systematic and detailed approach will maximise exploration success."
*To view tables and figures, please visit:
About Cohiba Minerals Limited
Cohiba Minerals Limited (ASX:CHK) is listed on the Australian Securities Exchange with the primary focus of investing in the resource sector through direct tenement acquisition, joint ventures, farm in arrangements and new project generation. The shares of the company trade under the ticker symbol CHK.
The Company recently acquired 100% of the shares in Charge Lithium Pty Ltd, which holds exploration licences in Western Australia.