Commodities major Glencore’s Horne Smelter has shelved its Aeris project, citing technical and operational challenges, and is now proposing a revised approach to reduce arsenic emissions while safeguarding the long-term viability of the Canadian plant.

Launched in 2024, the Aeris project feasibility study aimed to evaluate the copper smelter’s path to achieving a yearly arsenic concentration of 15 nanograms per cubic meter (ng/m³) in ambient air. However, Glencore said on Tuesday that the project, in its original form, was not feasible.

“Given the complexity of the Aeris project, implementing it fully would compromise the operational stability, as well as long-term viability of the plant,” the company said in a statement. “It would have extended the timeframe to achieve our emissions targets.”

The main factors that led to the abandonment of the Aeris plan include complex construction challenges owing to existing infrastructure and ground conditions, a larger-than-anticipated overhaul of the production system and technical limitations in integrating new technologies without affecting copper output.

Instead, Horne Smelter is advancing what it calls an “optimised approach", focused on encapsulating the smelting zone – covering major equipment such as the reactor, Noranda converter, and anodes – paired with high-performance purification systems. These technologies, already proven and compatible with the current process, are expected to improve air quality more predictably.

"I'm extremely proud of the rigorous work carried out by our teams,” said Vincent Plante, Glencore Canada executive general manager, North America copper value chain. “Thanks to their commitment, we've found a solution that will allow us to deliver results with more predictability than Aeris.”

The Horne Smelter, located in Rouyn-Noranda, has already made progress in cutting emissions. According to Glencore, average arsenic concentrations in ambient air at the government monitoring station dropped 46.5% from 2022 levels, reaching 39.1 ng/m³ in 2024 - below the regulatory limit of 45 ng/m³. The company added that 99% of the urban area of Rouyn-Noranda now registers arsenic levels at or below the 15 ng/m³ target.

“The team and I look forward to engaging with our stakeholders regarding this optimised approach,” Plante said.

Glencore said implementation of the new strategy would require government approval. The Horne Smelter produces 210 000 t/y of copper and precious metals and employs over 650 people, with additional downstream workers at its CCR refinery in Montréal.