Following on from its recent announcement of the best drill intersection to date on 15 September 2026, Tertiary Minerals plc is now pleased to announce the highest grade silver-copper intersection to date from the recent Phase 4 drill programme at the Discovery Zone in Target A1, Mushima North Project in Zambia. The new results follow the Company’s news releases regarding the laboratory analytical results on 1, 7 and 15 September 2026, and are from a further four drill holes.
All four holes intersected near surface, silver-copper-zinc mineralisation, with two holes ending in mineralisation and so both increase the known depth of mineralisation beyond the exploration target boundary and confirm that it remains open at depth. These results also include the highest grade individual assay result for silver to date on the Project.
Mushima North is located in the prospective Iron-Oxide-Copper-Gold region of Zambia and is located 28km to the east of the historic Kalengwa copper-silver mine which is currently under redevelopment.
Target A1 is a polymetallic, silver-copper-zinc prospect, where the Company has previously reported a near surface Exploration Target of 15-30 million tonnes at 40-60 g/t silver equivalent at the Discovery Zone.
Richard Belcher, Managing Director of Tertiary Minerals plc, commented:
“We are thrilled to report additional exceptional results for this Project with our highest-grade silver-copper mineralised intersection to date, returning 82m at 107 g/t silver equivalent from only 8m and including silver and copper assays of up to 659 g/t and 0.94%, respectively.
“These results released today, along with the results over the last few weeks, are incredibly compelling for the potential to expand the current known extent of mineralisation at the Discovery Zone. With multiple, shallow, higher-grade silver-copper intersections that extend the mineralisation beyond the current Exploration Target boundary. The true depth extent of mineralisation below the higher-grade zone is yet to be tested.
“Additional laboratory results for the remaining drill holes submitted for analysis are expected in the coming weeks and we look forward to updating our shareholders in due course”.
Drill programme and results
A total of 39 (3,639m) Reverse Circulation (“RC”) drill holes were drilled as part of the Phase 4 drill programme. For the drilling at the Discovery Zone, holes were collared along a series of east-west drill lines spaced approximately 100m apart (north-south) and 50m apart along the east-west lines and drilled to vertical depths of up to 128m. This was the maximum depth capability of the drill rig under the drilling conditions, in particular the higher-than-expected water table and resultant wet samples. Drilling was completed in two passes to allow the updating of the Company’s geological model as new data became available and to enable the programme to be more dynamic.
The aim of the drill programme is to provide additional drilling data to increase confidence in the continuity of the mineralisation to the level required to report a JORC-compliant Mineral Resource Estimate. Further information on the drill programme can be found in Company’s announcement on 8 June 2026.
The results in this announcement are for four holes only. Including these four holes, results for a total of 29 holes have now been released from across the Exploration Target. This total includes infill holes, expansion drilling around the Exploration Target mineralisation margin and drilling targeting the higher-grade mineralisation zone.
Accessory minerals such as bismuth, antimony and cobalt have also been intersected in these holes as well as being present in holes in previous drill phases. While the potential for these metals has yet to be evaluated, they are classified as critical, and, in some cases, strategic raw materials (e.g. by the European Commission). If it’s economically feasible to extract these accessory minerals along with the main silver-copper mineralisation, there could be a positive impact on future Project economics.
