Boliden has opened a new leaching plant and underground repository at its Rönnskär operations in Sweden as it looks to extract additional metal from residual materials at the smelter and store any remaining waste in a sustainable way.

For many years, residual materials from smelting processes containing copper, zinc and lead, among other elements, have been stored temporarily at the Rönnskär site.

These residual materials, together with future residues from production, will from this point pass through the newly built leaching plant where further metal extraction will take place. The remaining material will then be transported straight down to the underground repository, which is located about 350 m below the site.

This will see Rönnskär become the only copper smelter in the world with a long-term, sustainable on-site storage solution, according to Boliden.

Investments in the two facilities have amounted to SEK 1.4 billion ($160 million), Boliden says.

Daniel Peltonen, President Boliden Smelters, says: “Our aim is to extract as much metal as possible from our raw materials while ensuring the best achievable environmental and climate performance. The investments we have now made represent a new chapter in Rönnskär’s history in both of these areas.”

Rönnskär produced 226,000 t of copper, along with 33,000 of zinc clinker, 28,000 t of lead, 506,000 t of sulphuric acid, 524,000 kg of silver and 14,000 kg of gold last year, according to Boliden.