Prospect Resources Confirms Two Copper Finds at Mumbezhi in One Update

Prospect Resources confirmed two significant copper finds in a single programme update on 17 September 2026, with drill holes at Nyungu Central punching clean outside the existing resource boundary and a brand-new discovery now confirmed at Sharamba across more than 3 kilometres of strike.

The intercepts tell the scale of it. Drill hole NCDD033 returned 27 metres at 0.69% copper from 102 metres, while NCDD031 hit 5.1 metres at 0.99% copper from 173 metres. Both landed entirely outside the current Mineral Resource Estimate.

Prospect holds a 90% interest in Mumbezhi, a north-western Zambian Copperbelt project that already carries a total resource of 208.1 million tonnes at 0.42% copper. Phase 3 drilling was expanding that footprint before these results even arrived.

A Copperbelt project returning high-grade extensional intercepts beyond its resource boundary and confirming a new satellite discovery on the same day is not a routine quarterly update.

What follows here unpacks what the new intercepts mean for the resource growth story at Nyungu Central, why the Sharamba discovery changes the project’s exploration scale, and what both developments signal about where Prospect Resources sits in the current Zambian copper investment cycle.

What the new Nyungu Central intercepts reveal about the eastern flank

The value in these two holes is not just the grade. It is where they landed.

Both NCDD033 and NCDD031 sit entirely outside the current Indicated and Inferred resource boundary at Nyungu Central. They are not confirming what is already counted; they are adding ground that has not yet been booked into any resource category.

Both NCDD033 and NCDD031 sit entirely outside the current Indicated and Inferred resource boundary at Nyungu Central, meaning the tonnes they represent cannot be counted in a Mineral Resource Estimate until additional infill drilling meets the confidence thresholds required for resource classification.

Here are the intercepts reported in this update:

• NCDD033: 27 metres at 0.69% copper from 102 metres downhole, infilling mineralisation westward and up-dip
• NCDD031: 5.1 metres at 0.99% copper from 173 metres, infilling westward and up-dip
• NCDD031: a second interval of 3.8 metres at 0.95% copper from 132 metres

The structural story is what makes these extensions predictable rather than lucky. An unmineralised mafic intrusive rock unit, meaning a barren body of igneous rock, has been interpreted as a body over which the mineralised ore schist was pushed eastward along a thrust plane, leaving the eastern flank dipping toward surface. That geometry is why the up-plunge direction is returning wide, moderately to highly graded copper carried by chalcopyrite and chalcocite, the two dominant copper sulphide minerals here.

The geophysical data adds weight to the drill results. The same zone hosts a shallow, high-amplitude airborne electromagnetic (AEM) anomaly that the new intercepts sit directly beneath, and that alignment between geophysics and assay data removes much of the speculative element from the extension target.

The broadest new intercept NCDD033 returned 27 metres at 0.69% copper from 102 metres, the widest new intersection reported in today’s update, and it sits outside the existing resource boundary.

There is a second signal buried in the numbers. Of the 29 diamond holes drilled so far in the Phase 3 programme at Nyungu Central, assays for 20 remain outstanding, and 16 of those are priority holes spanning both resource extension and infill.

That tells you today’s results are the leading edge of a much larger data release, not the full picture. For anyone tracking the resource growth thesis, extensional hits outside a defined resource are the raw material for a future upgrade, and with 16 priority holes pending and the structural model pointing consistently east, the forward catalyst sequence is clear.

The JORC resource classification framework establishes the standard that Australian-listed explorers like Prospect must apply when reporting Inferred, Indicated, and Measured resource categories, with an independent Competent Person sign-off required before any estimate can be disclosed to the market.

Sharamba confirmed: what a 3-kilometre copper discovery means for Mumbezhi’s scale

The second half of the announcement is a discovery in its own right.

Initial assay results from the Sharamba prospect have confirmed a new copper discovery. Sharamba was previously flagged as a key regional exploration target within the broader Mumbezhi project area; it is now a confirmed find, and that changes its standing entirely.

The scale is the headline. The mineralised sequence at Sharamba extends over more than 3 kilometres in strike length, and Prospect considers the discovery significant enough to warrant substantial additional drilling, to be planned at a future date.

How a 3-kilometre strike compares to Zambian precedents

A 3-kilometre strike confirms Sharamba as a genuinely large-scale target. It does not, on its own, tell you how long the road to a resource estimate will be. Zambian sediment-hosted copper projects at a similar stage give a realistic reference frame.

Both Luansobe and Mushima North featured roughly 3-kilometre anomalies and needed multi-year drill campaigns before the resource stage. The World Bank’s energy-transition minerals roadmap for Zambia describes the typical horizon from discovery to production as 5-6 years or more, and even that is framed as an optimistic assumption.

The read for you is a calibrated one. A confirmed copper discovery on a satellite prospect sitting next to an existing 208-million-tonne resource meaningfully expands the total footprint Prospect is working with. The open question is how quickly drilling can move Sharamba from confirmation to resource definition, and the analogues suggest patience rather than a fast conversion.

Phase 3 drilling scale and the budget expansion driving it

The size of the Phase 3 programme puts today’s partial results in context.

Prospect is targeting approximately 26,000 metres of total drilling across Nyungu Central, West Mwombezhi, and regional prospects. That breaks down as follows:

• Roughly 60 diamond core holes
• Around 30 RC (reverse circulation) holes, a faster rotary drilling method used to sample broad zones
• About 320 scout aircore holes for shallow reconnaissance

Nyungu Central alone is allocated 16,000 metres of diamond drilling. That is a near 70% increase over the entire Phase 1 diamond total of 9,516 metres, which puts the scale of the step-up beyond incremental tinkering. On top of that, a further 6,000 metres of infill diamond drilling was planned to begin at Nyungu Central in late July 2026, specifically to upgrade Inferred resources to Indicated status, meaning to raise the confidence classification of the existing tonnes.

The bottleneck now is not the drill rigs. It is the laboratory.

Laboratory throughput constraints have become one of the most consistent bottlenecks across junior copper exploration programmes in 2025-2026, with assay queues at third-party facilities extending timelines that were already stretched by high drill-rig utilisation across the Copperbelt.

Drill results have been coming back faster than the assay laboratories can process them. To address this, Prospect has developed an accelerated testing route for the highest-priority extensional and infill holes at Nyungu Central and Kabikupa, which should reduce the lag between drilling and usable data.

The forward catalyst to watch As of 17 September 2026, assays for 20 Phase 3 holes remain outstanding, with 16 designated as priority. That volume of resource-defining data is the next material information release.

The read here is that the rate-limiting factor on resource growth at Mumbezhi has shifted from drilling capacity to laboratory throughput. If Prospect resolves that constraint, future result releases could accelerate materially, and the 16 outstanding priority holes are the first test of whether that acceleration arrives.

Zambian Copperbelt context and what it means for projects like Mumbezhi

A discovery is only as valuable as the market that wants it. Right now, the macro backdrop for Zambian copper is doing Prospect no harm.

The demand case is structural, not cyclical:

• Global copper demand is projected to rise 50-70% over the next two decades
• An expected global copper mine supply shortfall of around 10 million tonnes per year by 2034
• Only about 49-55% of Zambia’s mineral-rich land has been geologically mapped, leaving substantial ground untested

That combination, rising demand against constrained supply in an underexplored jurisdiction, is what makes new Zambian discoveries structurally significant rather than locally interesting.

The Zambian investment climate in 2025-2026

The Zambian government has moved to pull capital in. It has attracted approximately US$12 billion in mining investment commitments since 2022, launched a nationwide high-resolution airborne geophysical survey in August 2024, and rolled out the Zambia Integrated Mining Information System in February 2025 to digitise licence management.

The Zambian mining investment climate has shifted materially since 2022, with regulatory reforms, digitised licence management, and government-backed geophysical survey programmes collectively reducing the administrative friction that historically deterred institutional capital from committing to exploration-stage projects.

Institutional capital is following. Ivanhoe Mines allocated US$50 million to its 2025 Zambian exploration programme, covering 102,000 metres of diamond drilling and 18,000 metres of RC drilling, a clear signal that major producers now treat Zambia as a priority exploration jurisdiction.

For a reader weighing Prospect’s position, the concentration of institutional capital and the volume of unmapped ground mean Mumbezhi operates in a jurisdiction where discovery risk is high but the structural conditions for a major find are genuinely present. A confirmed discovery with 3-kilometre strike, sitting alongside an established 208-million-tonne resource, is entering the market at a point when institutional appetite for exactly this kind of exposure is near its strongest in years.

What today’s results change, and what still needs to be proved

Two threads run through this announcement, and it is worth separating what is now established from what remains to be demonstrated.

What is established: high-grade copper mineralisation is extending beyond the Nyungu Central resource boundary in a structurally coherent direction, and a new discovery at Sharamba covers more than 3 kilometres of strike. Against a current total Mumbezhi resource of 208.1 million tonnes at 0.42% copper, of which Nyungu Central contributes 154.4 million tonnes at 0.42% copper, both developments expand the total project footprint.

Two forward catalysts now define the near term:

1. The release of the 16 outstanding priority assay results from Phase 3 extensional and infill drilling, which will either confirm or complicate the eastern flank extension case.
2. The scoping of a dedicated drill programme at Sharamba to begin converting more than 3 kilometres of strike into a maiden resource estimate.

The risk sits between confirmation and conversion.

For readers wanting to understand how extensional intercepts translate into upgraded resource categories, our complete guide to Mineral Resource Estimates covers the geostatistical modelling process, confidence thresholds, and the drilling density standards that separate Inferred from Indicated tonnes.

The structural caveat Reactivated faults in Copperbelt thrust systems can segment ore lenses, producing abrupt thickness and grade changes where drill density is insufficient. The current spacing outside the existing resource boundary is not yet enough to confirm whether the extensions are continuous or episodic.

The read you should take is measured. Today’s results are a strong positive signal, but they are not yet proof of a larger continuous resource. The 16 pending priority assays are the next concrete data point, and they will either strengthen the extension narrative or reveal the grade variability that would force the resource model to be revised.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions.

Past performance does not guarantee future results. Financial projections are subject to market conditions and various risk factors. Forward-looking statements regarding future drilling and resource estimates are speculative and subject to change based on market developments and company performance.