Weir’s ENDURON HPGRs Target Hard-Ore Bottleneck at Akyem

Weir PLC has won a contract to supply two ENDURON high-pressure grinding rolls to Zijin Mining Group’s Akyem gold mine in Ghana, a deployment built to break a grinding bottleneck caused by ore that has simply become too hard for the existing circuit to handle at an efficient cost.

Akyem is not a short-life asset. The mine runs a conventional carbon-in-leach plant processing 8.5-8.6 Mtpa and carries a stated mine life extending to 2042. As the orebody deepens and the rock grows more competent, the SAG and ball mill circuit that built the operation is struggling to keep pace, and the HPGR order, recorded in Q3 2026, signals Zijin is treating this as a decades-long infrastructure question rather than a quick fix.

The Akyem contract offers a concrete case study in where the mining industry’s grinding technology choices are heading. Here is what the deployment reveals about the shift toward high-pressure grinding at long-life, hard-ore operations, and why more announcements of this type are likely to follow.

Two HPGRs ordered to crack a hard-ore bottleneck at Akyem

The problem came first, and it is a familiar one for ageing open pits. As Akyem’s pit has deepened, the ore feeding the plant has become harder and more competent, and a conventional SAG and ball mill circuit processes that kind of rock less efficiently and at higher cost.

Zijin’s response, executed through its Golden Ridge operation at the site, was to bring in high-pressure grinding rolls rather than rebuild the circuit from scratch. High-pressure grinding rolls, or HPGRs, crush ore by squeezing it between two counter-rotating rolls under intense pressure, a more energy-efficient method than the tumbling action of conventional mills.

The two ENDURON units, supplied by Weir and recorded in Q3 2026 with public announcements following in early September 2026, are configured for pebble processing. In practice, that means they target a specific choke point inside the existing circuit rather than replacing it.

Here are the core contract facts:

• Mine: Akyem open-pit gold mine, Ghana
• Operator: Zijin Mining, via its Golden Ridge operation
• Equipment: Two Weir ENDURON high-pressure grinding rolls
• Function: Pebble processing to relieve grinding bottlenecks in the SAG and ball mill circuit
• Recorded: Q3 2026, announced early September 2026
• Mine life: Extending to 2042

This is a brownfield optimisation programme, not a greenfield rebuild. The goal is higher throughput and improved ore recovery from infrastructure that already exists.

Bjorn Dierx, Weir’s director of HPGR and process engineering The advantages of ENDURON HPGRs, including reduced energy consumption, lower carbon output and superior grinding efficiency compared with conventional tumbling mills, are well established. The Akyem project highlights the equipment’s value in circuit debottlenecking and pebble crushing scenarios.

What this tells you is that HPGR adoption does not always demand a full circuit redesign. An operation can slot the technology in at a single bottleneck, which lowers the capital barrier and explains why these orders keep turning up at existing mines rather than only new builds.

The Platreef HPGR deployment by Ivanhoe Mines represents another high-profile vote of confidence in Weir’s ENDURON platform, with that project similarly prioritising energy efficiency and processing performance at a large, long-life hard-rock operation.

Specific roll dimensions, installed motor power and commissioning timelines for Akyem have not been publicly disclosed.

Why harder ore is forcing a rethink of conventional grinding circuits

The logic behind the Akyem choice is playing out across the industry. As near-surface deposits are exhausted, miners are digging into deeper, harder and more competent rock, and conventional SAG and ball mills grind that material less efficiently and burn more power doing it.

That energy gap is where HPGR earns its place. Industry data shows HPGR installations deliver grinding-circuit energy savings of 20-30%, reaching up to 40% for particularly hard ores, against conventional tumbling mills. Weir puts its own ENDURON figure at up to 40% total power reduction, roughly 25% in direct comminution and a further 15% downstream.

The historic objection to HPGR in hard-rock gold and copper work was roll wear, since abrasive ore chewed through the surfaces too quickly. Modern wear-resistant materials, tungsten carbide and nanocomposite roll linings, have largely resolved that constraint, which is what opened the technology to applications like Akyem.

Advanced comminution technologies, spanning HPGR, vertical roller mills, and stirred media grinding, are collectively reshaping how the industry approaches size reduction, with each offering different trade-offs between capital cost, energy draw, and ore-type suitability.

The decarbonisation case alongside the efficiency case

The energy argument carries a second payoff. Comminution accounts for roughly 25% of on-site energy consumption at a mine, so cutting its power draw moves the whole site’s carbon profile, not just one circuit.

The figures back that up. Avoided emissions from a single HPGR installation can reach 12,000-16,000 tonnes of CO2 per year, and because HPGR reduces or eliminates the need for steel grinding media, it strips out embodied carbon as well.

Mine-site decarbonisation strategies increasingly treat comminution as the highest-leverage intervention point, given that grinding typically accounts for a larger share of site energy than any other single process and represents a cost that compounds over a multi-decade mine life.

For a mine running to 2042, those savings are structural rather than marginal. The decarbonisation benefit compounds over decades, and with ESG reporting and emissions regulation tightening, it reinforces the purely economic case rather than competing with it.

A verified deployment shows what this looks like in practice. Australia’s Tropicana Gold Mine reached 95% availability and hit its 5.8 Mtpa throughput target within six months of start-up, a useful benchmark for what a well-executed HPGR ramp-up can deliver.

What Akyem signals for brownfield HPGR adoption, and what to watch next

Shift the frame from this one contract to the pattern it represents, and a clearer picture emerges. Zijin’s long-term throughput target at Akyem is more than 13 Mtpa, well above current capacity, which suggests these two HPGRs are a step in a longer capacity ramp rather than a standalone repair.

That scale of integration is already proven elsewhere. Large hard-rock HPGR installations at Cerro Verde in Peru and Grasberg in Indonesia operate at mine sizes substantially larger than Akyem, so the engineering risk here sits within a well-tested envelope.

Brownfield integration does come with real constraints, and they are worth stating plainly:

• Feed top-size control, requiring closed-circuit secondary crushing and screening to protect the rolls
• Moisture sensitivity, with optimal feed moisture at 2-4% and degraded performance above 5%
• Wear-part logistics, since roll tire life of around 12,000 hours for certain ores still depends heavily on ore type, and remote sites face longer downtime if replacements are not managed
• Capital and circuit integration, since matching capacities and adding screening or conveying infrastructure carries upfront cost

None of these is a dealbreaker given the track record at comparable operations, but each shapes whether a given site is a realistic candidate.

For readers tracking how this unfolds, two indicators matter most:

1. Commissioning confirmation, since no delivery or commissioning date has been publicly disclosed at this stage
2. Throughput expansion updates, specifically any Zijin announcement moving Akyem toward the 13 Mtpa target

Zijin’s production numbers frame the stakes. Akyem produced 6.4 tonnes of gold in 2024 before Zijin’s acquisition, and post-acquisition output in 2025 reached approximately 5.1 tonnes (164 koz), which the company reported as exceeding its annual plan. Anyone with exposure to mining equipment, gold production or West African mining will want the next capacity update to gauge how quickly this investment converts into measurable throughput.

Zijin’s Akyem project page confirms the April 2025 acquisition and reports gold output of 5.1 tonnes on a 100% basis from mid-April through year-end, the production baseline against which the HPGR-driven capacity expansion will be measured.

Bjorn Dierx, Weir’s director of HPGR and process engineering Choosing ENDURON HPGRs for an operation with an extended horizon effectively future-proofs the grinding circuit, delivering energy efficiency, adaptability to hard and variable ore feeds and a reduced environmental footprint over the long term.

What the Akyem contract tells the industry about where grinding technology is heading

Pull the three threads together and the position is clear. Akyem presents a named engineering problem, harder ore defeating an existing circuit; a quantified fix, energy savings of 20-40% and avoided CO2 of 12,000-16,000 tonnes a year; and an adoption pattern, brownfield pebble crushing layered into a long-life operation targeting more than 13 Mtpa.

The constraints are genuine. Brownfield integration is complex, moisture sensitivity is unforgiving above 5%, and remote logistics can stretch downtime. Yet the verified record at comparable sites, and Tropicana’s 95% availability and six-month ramp-up, shows those hurdles are surmountable with sound execution.

The future-proofing thesis is not really a supplier slogan; it is operational arithmetic. A mine running to 2042, facing harder rock and rising energy costs, has a compounding incentive to grind at lower energy over the remaining life.

Those same conditions, long mine life, hard ore, an existing SAG and ball circuit under strain, and expansion ambition, exist at dozens of operations worldwide. Akyem is the clearest recent evidence that brownfield pebble-crushing HPGR is the near-term growth vector, and its ramp-up results will be closely watched.

A brownfield optimisation strategy of this type, layering capital-efficient technology into existing infrastructure rather than commissioning new capacity, has become a dominant playbook across the resources sector as permitting timelines lengthen and greenfield development costs rise.

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. Financial projections are subject to market conditions and various risk factors, and forward-looking statements are speculative and subject to change based on market developments and company performance.