Aim-listed Tertiary Minerals has reported further encouraging silver, copper and zinc drilling results from its Mushima North project in Zambia, with mineralisation extending beyond the previously defined exploration target and remaining open at depth.
The company announced on November 9 that final laboratory assay results from its Phase 4 reverse-circulation (RC) drilling programme had confirmed significant near-surface polymetallic mineralisation at the Discovery zone, while additional drilling had identified copper mineralisation at the Western zone.
The latest results cover eight additional RC holes, six of which were drilled at the Discovery zone. Three of the six holes ended in mineralisation, extending the known depth of the mineralised system beyond the existing exploration target boundary.
Among the significant intersections, drill hole 26TMNRC-078 returned 70 m grading 31 g/t silver, 0.29% copper and 0.25% zinc from 10 m downhole. The intersection included a higher-grade section of 6 m at 84 g/t silver, 0.32% copper and 0.29% zinc.
A second hole, 26TMNRC-079, intersected 68 m grading 27 g/t silver, 0.15% copper and 0.52% zinc from 17 m downhole. This included 17 m grading 53 g/t silver, 0.13% copper and 0.52% zinc.
Tertiary cautioned that the reported intersections represent downhole lengths and that their true widths have not yet been established.
At the Western zone, two scout drilling holes confirmed the presence of shallow copper mineralisation. One returned an intersection of 24 m grading 0.29% copper from 19 m downhole, including a higher-grade interval of 5 m at 0.60% copper.
Mushima North is situated within Zambia’s prospective iron-oxide-copper-gold geological belt, approximately 28 km east of the historic Kalengwa copper-silver mine, which is currently undergoing redevelopment.
The Discovery zone forms part of Target A1, a polymetallic silver-copper-zinc prospect for which Tertiary has previously outlined a near-surface exploration target of 15-million to 30-million tonnes grading between 40 g/t and 60 g/t silver equivalent.
The Phase 4 campaign comprised 39 RC holes totalling 3 639 m, making it the largest drilling programme undertaken at the project to date. Its objectives included increasing drilling density to support a maiden mineral resource estimate, extending known mineralisation beyond the exploration target and investigating the newly identified Western zone.
Tertiary managing director Richard Belcher described the combined drilling results as compelling, saying the latest assays marked the completion of the company’s largest exploration drilling campaign at Mushima North.
He said the company was particularly encouraged by the evidence of mineralisation extending beyond the existing exploration target and was looking forward to investigating its depth potential.
Meanwhile, Tertiary has commenced its Phase 5 diamond drilling programme, which began on November 8. The programme comprises four planned diamond drill holes designed to investigate mineralisation beneath the Discovery zone and assess the potential for primary sulphide mineralisation at depth.
The deeper drilling will also improve understanding of the deposit’s geological and structural characteristics and provide drill core samples for additional metallurgical and technical studies.
Initial metallurgical testwork results are expected shortly and will help inform the preparation of a maiden mineral resource estimate, which the company aims to deliver before the end of 2026.
The latest results represent an important step in advancing Mushima North from an exploration target towards a defined mineral resource, although further drilling, metallurgical work and resource modelling will be required to establish the deposit’s full extent and economic potential.
