Significant Botswana Copper Targets Identified
Sydney, Dec 16, 2020 AEST (ABN Newswire) - Cobre Limited (ASX:CBE) is pleased to provide the following update on Kalahari Metal Limited's (KML) exploration activities in Botswana through KML's wholly owned Kitlanya East (KIT-E) project.
KML is subject to an agreement between Cobre and the existing shareholders of KML under which Cobre Kalahari Pty Ltd (a wholly owned subsidiary of Cobre) will acquire up to a 51% interest in KML (Transaction). Completion of the Transaction is subject to a number of conditions precedent being satisfied, including shareholder approvals at an Extraordinary General Meeting to be convened early next year.
A stratigraphic drilling programme consisting of 5 diamond drill holes (KITE01-05) totalling 1,709m has been completed along with additional phases of soil sampling. The field programmes have been designed to target geological settings analogous to neighbouring Sandfire Resources' T3 and A4 deposits along the northern margin on the KIT-E project (North Target). These results have been tied in with recently identified historical core which has been relogged. Airborne electromagnetic (AEM) data covering the target has been reprocessed to extract further structural information. Results from this phase of field work have been used to identify several compelling areas for follow-up drill testing.
Highlights from the exploration programmes include:
- Stratigraphic drilling programmes have confirmed the presence of D'Kar Formation stratigraphy including dark carbonaceous siltstones often used as markers in the lower part of the D'Kar stratigraphy which correlate with conductors in the AEM data;
- Trace Cu, Pb and Zn mineralisation has been identified on thrust/shear planes and in underlying extensional zones associated with dilational quartz-carbonate veins (KITE-02 and KITE-05);
- Sericite, albite and haematite alteration often associated with the distal portions of mineral deposits in the Kalahari Copperbelt has been identified in proximity to several thrust zones (KITE-02 and KITE-05)
- Soil sampling programmes have identified significant Cu and Zn anomalies demonstrating a distinct correlation with thrusts interpreted from high-resolution magnetic data
- Remodelling of the AEM data has provided significant additional information on fold geometry which has been correlated with stratigraphic drill results to prioritise 'dome' targets for followup drilling.
Results from the recent phase of exploration support the potential for shallow Cu-Ag mineralisation in a similar setting to the neighbouring Sandfire Resources A4 deposit.
A total of 1,709m of diamond drilling was carried out in two phases due to lockdown restrictions by OreZone Drilling. Five holes (KITE-01-05) were drilled along the northern margin of the KIT-E project using AEM conductors as a guide. Two of the five holes (KITE-01 and KITE-03) were abandoned due to poor intersection angles (being replaced by KITE-02 and KITE-04). Drill collar positions are illustrated in Figure 2*.
Results from the stratigraphic drilling are summarised as follows:
o Intersects package of siltstones, sandstones and marls of the lower D'Kar Formation.
o Includes intersections of carbonacaeous siltstone unit, corresponding with the position of AEM conductors
o Intersection of several zones of shearing and dilational veining (quartz-carbonate) often with trace Cu-Pb-Zn mineralisation.
o Higher proportion of siltstone to sandstone, low magnetic susceptibility, carbonaceous siltstone units, and abundant pyrite and pyrrhotite suggests this is lower in the D'Kar Formation stratigraphy than other holes.
o Intersects package of sandstones and siltstones in the middle D'Kar Formation o Several shear zones and mylonitic thrusts were intersected with extensive associated hydrothermal alteration.
o High magnetic susceptibility, sandstone composition and dominance are more indicative of transition zone to middle D'Kar Formation.
o Intersects a package of sandstones and siltstones probably in the lower portion of the middle D'Kar Formation.
o Extensive pyrite and pyrrhotite with several intersections of trace Cu, Pb, Zn associated with quartz-carbonate veining.
o Low magnetic susceptibility and higher proportion of siltstones vs KITE-04 and minor carbonaceous siltstone intersections suggest this hole is located lower in stratigraphy (although probably higher than KITE-02).
In addition to the recently completed holes, drill core from historical drilling was located and relogged.
Of particular interest are holes NH01-07D which, combined with KITE-05, provide a NW-SE section across the main structure of interest. Results are summarised as follows:
- All holes are located in the D'Kar Formation
- NH01D and NH02D are likely in the lower portion of the middle D'Kar Formation
- NH03D - NH06D intersect units in the middle D'Kar Formation
- NH07D is likely in the upper portion of the D'Kar Formation
These results describe a broad anticlinorium with superimposed doubly plunging anticlines and synclines. The presence of mid to lower D'Kar Formation stratigraphy, abundant pyrite, pyrrhotite and carbonaceous siltstones provides encouragement that the stratigraphic position in the D'Kar Formation, host rocks and trap-sites are analogous to neighbouring T3 and A4 deposits. Intersection of thrusts with hydrothermal alteration, dilational quartz-carbonate veining and associated trace Cu-Pb-Zn mineralisation provide evidence for the development of appropriate fluid pathways.
A total of 1,101 soil samples were collected over the North Target, providing infill to an earlier phase of regional soil sample traverses. Samples were screened to -90 um fraction and analysed using a Niton pXRF along with appropriate blanks and standard reference samples. The pXRF results provide a useful first pass review prior to sending samples for laboratory assay.
Soil sampling results have identified distinct Cu and Zn anomalies which correlate with historical Terraleach TL1 Cu sampling results on the western portion of the North Target. Of particular interest is the relationship between Cu anomalies and interpreted thrusts suggesting the metal source may be introduced along thrust faults.
Reprocessing of AEM Data
AEM data collected over the north target area in 2019 using NRG's XCite system has been reprocessed and inverted using GALEI software which has extracted additional structural information vs previous results. Interpretation of results has aided identification of anticline hinge zones which present targets for Cu-Ag mineralisation.
Stratigraphic drilling has confirmed the potential for shallow structurally controlled Cu-Ag mineralisation associated with anticlines in the North Target. Given the proximity to the T3 and A4 deposits and recent high-grade drill results released by Sandfire Resources (ASX SFR 1 December 2020), the area is considered a priority for follow-on drill testing.
Priority areas for drill testing have been identified using a Knowledge-driven Mineral Systems Analysis approach using the A4 deposit as a guide. Essentially key vectors to mineralisation relating to trapsite geology (stratigraphy, proximity to conductive carbonaceous siltstones, anticlines and local fold hinges), pathways for hydrothermal fluid movement (thrusts, shears, faults, fault jogs, WNW trending structures and dislocations) and evidence for alteration (breaks in AEM conductors) and Cu mineralisation (Cu and Zn soil anomalies) have been combined to create a prospectivity map highlighting priority areas.
Michael McNeilly, Chief Executive Officer of Metal Tiger, commented:
"We are excited to report that the work at the KML Kitlanya East Project, located in the highly prospective Kalahari Copper Belt, has with the integration of analysis of the stratigraphic drilling interpretation, reprocessed airborne geophysics and soil sampling data, identified multiple stratigraphic dome targets that we consider highly prospective for hosting copper-silver mineralisation. Given its proximity to the Sandfire T3 development project and A4 resource and prospect, this is of significant value".
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About Cobre Limited
Cobre Limited (ASX:CBE) is a copper and base-metals explorer with projects in Western Australia and Botswana. The Company recently discovered a new high-grade VMS deposit enriched in Copper, Gold, Zinc and Silver in Western Australia, and is currently exploring approximately 8,100 km2 of tenements within the Kalahari Copper Belt (KCB) in Botswana.
Sandfire Resources Ltd
Metal Tiger plc