Zimplats has reintroduced open-pit mining operations for the first time in years, responding to operational challenges from a shortage of trackless mobile machinery (TMM) and a decline in underground output.
By Ryan Chigoche
The decision to resume open-cast mining in January 2025 helped mitigate a drop in production volumes, with the open pit contributing 76,000 tonnes, or 4.3% of total mined volumes during the quarter.
Underground mining volumes saw a significant decline, falling by 11% year-on-year and 4% compared to the previous quarter. The shortfall in TMM availability forced Zimplats to adjust its operations, leading to the strategic shift. However, the lower-grade ore from the open pit had an impact on the company’s overall ore quality, with the 6E head grade improving by 1% year-on-year but falling by 1% from the previous quarter.
In addition, milled volumes dropped 17% compared to the same period last year and 8% from the previous quarter due to inconsistent ore supply. This decline in milled volumes led to a 20% drop in 6E concentrate production, with total adjusted output reaching 135,172 ounces, 15% lower than the prior quarter.
Despite these challenges, final metal production was slightly stronger, with Zimplats reporting 139,506 ounces of 6E produced—a 16% decline year-on-year but an 8% increase compared to the previous quarter. This recovery was driven by the smelting of 60,000 tonnes of previously accumulated concentrate inventory, although the company noted that around 12,100 ounces remained tied up in furnace reverts and matte. Another 16,000 ounces are expected to be released in the upcoming quarter.
The financial side of the business also reflected rising operational costs. Operating cash costs increased by 3% year-on-year due to higher energy demands from the new 38MW smelter and additional expenses tied to restarting open-pit operations and replacing key components. However, the cost per ounce of 6E metal produced climbed to US$1,026, reflecting a 25% year-on-year increase and a 10% rise from the previous quarter, driven by lower production volumes.
While the decision to resuscitate open-pit mining is seen as a short-term fix, it reflects Zimplats’ ability to adapt in the face of operational hurdles. The company continues to navigate significant challenges, including equipment shortages and declining volumes, while positioning itself for future stability and growth.
Meanwhile, exploration efforts remained active during the quarter. Zimplats drilled eight exploration holes totalling 2,178 metres at its Bimha and Mupani mines. These focused on guiding decline development and mapping geological structures within the five-year mining footprint, critical for long-term operational stability and mine planning.
In parallel, several major capital projects continued to progress. The development of Mupani Mine, set to replace the depleted Rukodzi and Ngwarati operations, remains on schedule for full production in the first half of FY2029. To date, US$342 million has been spent out of a total budget of US$386 million.
Zimplats’ Smelter Expansion and SO₂ Abatement Plant Project also showed significant progress, with a combined US$452 million spent to date against a US$544 million total budget. Phase 1, which includes smelter expansion and initial SO₂ off-gas handling, is technically complete. Phase 2, covering wet gas cleaning and a sulphuric acid plant, is ongoing.
Additionally, the 35MW solar plant, commissioned in August 2024, has reached full generation capacity as of December and was completed within the US$37 million budget, strengthening the company’s energy resilience. Progress also continues on the Base Metal Refinery refurbishment, with US$33 million spent to date out of a total budget of US$190 million.
Despite these strategic developments, the quarter was financially challenging. Operating cash costs rose 3% year-on-year due to increased energy usage from the new smelter, open-pit mining expenses, and delayed equipment replacement. However, lower variable costs from reduced volumes led to a 2% quarter-on-quarter improvement.
The 6E unit cost of production rose sharply to US$1,026 per ounce—up 25% year-on-year and 10% quarter-on-quarter—highlighting pressure on profitability from falling volumes.
As Zimplats looks ahead, its focus will remain on stabilising underground operations, unlocking in-process inventory, and executing capital projects that promise long-term efficiency and growth. The revival of open-pit mining may be temporary, but it reflects a broader theme: the company’s readiness to adapt and deliver, even in tough quarters.
