By: African mining market

Tertiary Minerals plc has announced the laboratory analytical results from the first two drill holes in the recent follow-up drill programme at Target A1 at its Mushima North Project in Zambia. The results extended the previously announced thick, near surface intervals of silver mineralisation (with lower grade copper and zinc) for a further 225m to the north.

Mushima North is located in the prospective Iron-Oxide-Copper-Gold region of Zambia. Target A1 is a polymetallic, silver-copper-zinc prospect located 28km to the east of the historic Kalengwa copper-silver mine which is currently under redevelopment.

Richard Belcher, Managing Director of Tertiary Minerals plc, commented:
“We are excited to report the first laboratory analytical results from the recent Phase 2 drill programme, including our highest intercepts for both silver and copper so far. These results increase the extent of the thick, near surface intervals of silver mineralisation a further 225m to the north of the previous drilling. The silver mineralisation remains open and is supported by the recently announced portable X-Ray Fluorescence results which indicate the mineralisation footprint is larger, at least approximately 350m by 300m.

“The results, albeit for only the first two drill holes of the programme, are very encouraging and provide further support for the potential of Target A1 as a primarily silver target. Wide intervals of near surface silver with higher-grade intervals, for example 73m at 32 g/t silver, including 11m at 94 g/t silver, support our bulk tonnage, open pit silver exploration model. These silver grades and widths (supported by copper and zinc values) are comparable to silver grades and widths from open pit silver deposits elsewhere in the world. As such we are also now looking at undertaking mineralogical studies as part of the initial metallurgical testing to better understand the mineralisation style and metallurgical properties and potential processing options.

“We eagerly await the additional analytical results in the coming weeks for the other drill holes and the mineralogical/metallurgical work thereafter.”

Phase 2 Drill Programme

A programme of 1,116m of combined Air Core (“AC”) and Reverse Circulation (“RC”) drilling has now been completed, with a series of east-west drill lines spaced between 100 and 250m apart (north-south). Holes were collared approximately 100m apart along the east-west lines and drilled to the maximum depth possible based on the drill rig capabilities and geological ground conditions (the bit refusal depth). The deepest drill hole in this programme was 90m and the average hole depth 70m. Combined Phase 1 and 2 drilling covers a surface footprint of approximately 1,680m by 550m.

The two holes reported here are:

• 25TMNAC-025: Located on drill line 8506925N and collared between holes 24TMNAC-005 and 25TMNAC-015 (Phase 1 drilling). This hole was drilled vertically and to a depth of 90m to test the depth of oxide-related mineralisation in this area and infill between previously reported holes 24MNAC -05 and 24MNAC-15.
• 25TMNAC-026: Located on new drill line 8507150N approximately 225m to the north of line 8506925N, the most northerly line drilled in Phase 1. Line 8507150N is made up of five holes collared over a width of approximately 400m and was designed to test the continuation of mineralisation to the north. Analytical results for the other four holes on this drill line are awaited.

Target A1

Target A1 is a large copper-in-soil anomaly (3.1km by 1.7km) with copper values up to 350ppm (per Portable X-Ray Fluorescence, “pXRF”) associated with a 1.7km by 0.5km zinc- and coincidental 1.3km by 0.3km silver-in-soil anomaly. Phase 1 drilling in 2024 over the silver- and zinc-in-soil anomaly (drill line: 8506925N) identified wide and thick, near surface silver mineralisation associated with low-grade copper and/or zinc mineralisation. Elevated bismuth (up to 991 g/t), and the critical minerals antimony (up to 824 g/t) and gallium (up to 40 g/t) are also associated with the mineralisation in places.

PXRF analyser results indicate a current extent of mineralisation over a footprint of approximately 350m by 300m and to a depth from near surface to 84m. However, zinc and copper mineralisation remains open-ended to the north and at depth, whilst the potential extent of silver mineralisation remains to be determined from the on-going laboratory analysis.

The mineralisation at Target A1 is associated with a massive, haematitic and carbonaceous silty-sandy conglomerate. Where visible, copper mineralisation is in the form of secondary copper minerals malachite and chrysocolla. The mineralogical speciation of silver and zinc is yet to be determined.

Drilling results from the Phase 1 drilling programme undertaken in late 2024 included:

• 65m at 23 g/t Ag, 14% Cu, 0.27% Zn from 9m downhole (24TMNAC-005).
  – Including: 5m at 73 g/t Ag, 16% Cu, 0.31% Zn from 69m downhole.
• 66m at 26 g/t Ag, 13% Cu, 0.26% Zn from 13m downhole (24TMNAC-006P).
  – Including: 20m at 40 g/t Ag, 21% Cu, 0.40% Zn from 23m downhole.
• 57m at 25 g/t Ag, 2% Cu, 0.16% Zn from 14m downhole (24TMNAC-004).
  – Including: 26m at 36 g/t Ag, 20% Cu, 0.20% Zn from 45m downhole.

Mushima North Project

The Mushima North (silver-copper-zinc) Project (Licence 27068-HQ-LEL) is held through Group company Copernicus Minerals Limited, which is 90% owned by Tertiary Minerals (Zambia) Limited and 10% owned by local partner, Mwashia Resources Limited.

The Project’s western boundary lies 20km to the east of the Kalengwa copper-silver mine in northwest Zambia, one of the highest-grade copper deposits ever to be mined in Zambia (approximately 4 million tonnes at 5.2% copper and 40-80 g/t silver). In the 1970s, high-grade ore, reportedly averaging approximately 11% copper, was trucked for direct smelting at other mines in the Copperbelt. The Kalengwa mine is currently under redevelopment and is expected to produce 15,000 tonnes of copper annually.

Several prospective targets have been defined thus far within the Project based on reviews of historic geochemical and geophysical survey data against the current exploration model developed by Tertiary (Targets A1, A2, B1, B2, B3, C1 and C2). At the end of the summer 2024, Tertiary completed an initial (Phase 1) 25 AC drill hole programme (1,274m) to test parts of geochemical (copper-in-soil) anomalies at Targets A1 and C1. This limited and shallow drilling indicated wide downhole intervals of largely coincidental copper, zinc and silver mineralisation at Target A1. Numerous other geochemical and/or geophysical targets (A2, B1, B2, B3, C2) are yet to be drill tested.

The Project is held under a technical cooperation agreement with First Quantum Minerals Limited (“FQM”), which allows Tertiary to benefit from FQM’s historic exploration data in the area, as well as FQM’s geological team’s extensive experience and understanding of the area’s geology. The agreement is non-binding to any further agreement and there are no commercial restrictions for Tertiary, nor does FQM have a right of first refusal over the Project.

Sampling, Analysis and QAQC

Sampling from the drilling programme was undertaken at 1m intervals and two subsamples were collected from each interval using a riffle splitter: one for potential laboratory analysis, the other for future reference.

Samples have been initially analysed on site using a pXRF analyser for zinc and copper. Analysis protocol included multiple point (three) analyses per sample (unprepared sample analysed through a thin plastic sample bag) and the inclusion of Certified Reference Material, blanks and duplicate samples as part of an internal Quality Assurance (“QA”) procedure. Given the nature of the unprepared sample and point analysis, this method is used as a preliminary exploration technique to provide an approximate quantitative measure of copper and zinc mineralisation only.

Samples from selected drill holes based on the initial pXRF results will now be sent to the independent laboratory ALS Global in South Africa for analysis for a range of elements using a four-acid digest, method code ME-ICP61 (including silver, copper, zinc, bismuth, antimony and gallium). QA samples (Certified Reference Material, duplicates, blanks) will be inserted and monitored as part of the Quality Assurance Quality Control (“QAQC”) protocol.

Reported drill hole intersection thicknesses are downhole thicknesses and true thicknesses are unknown. Intersections are weighted averages based on silver, using a cut-off grade of 10 g/t Ag with up to 3m consecutive internal dilution and intervals starting and ending with ≥10 g/t Ag.