Extractive waste and slag

By their nature, mining and smelting operations have the potential to impact natural environments, ecosystems, and biodiversity – both directly and indirectly. Therefore, internal waste storage facilities, such as landfills, waste rock piles and tailings facilities, which are required for our operations, mean that land, ecosystem, and biodiversity management must be prioritized. Besides industrial waste, our operations produce large quantities of extractive waste (such as tailings and waste rock) and smelter waste (such as slag and sludge), which is managed in a responsible and safe way. Our operations also generate waste in water and gas purification processes, which is managed according to local requirements.

Tailings are a common by-product of the mining process, and tailings management is a critical element in the development, design, operation, and closure planning of mines. The latest global dam safety guidelines known as the Global Industry Standard on Tailings Management (GISTM) have been issued on the initiative of the International Council on Mining and Metals (ICMM), the United Nations Environmental Program (UNEP) and the Principles of Responsible Investments (PRI) industry organization. The standard strives to achieve the goal of zero harm to people and the environment. It also focuses on tailings management and contributes to greater global transparency and uniformity. We aim to complete the implementation of the standard by August 2023 for facilities with "Extreme" or "Very high" consequences in the event of potential dam failure (according to the standard's classifications system) and for remaining facilities by August 2025.

Two of Boliden’s Mines are rated as facilities with very high consequences. A high-level structure for the site-specific implementation was ongoing during 2022. Implementation will also occur at smelter sites at landfills that have dams covered by GISTM (Kokkola and Harjavalta). Boliden Smelters’ dams are currently managed and controlled according to national dam safety regulation.

During 2022, large investment projects related to tailings management commenced and continued – both to enhance our operations and minimize risk. For example, Boliden’s mine sites increased their tailings storage capacity with planned dam uplifts and risk assessments have been performed in accordance with current standards to minimize risks. We have worked on the development and implementation of a strengthened governance model for tailings management. The objective is to ensure a life-cycle approach for all tailings facilities by evaluating innovations and technologies as an integrated part of our sustainable waste management research program.

We work continuously to identify opportunities for internal and external recycling or landfill solutions for any process waste generated. We receive significant amounts of waste from external parties for recycling, construction purposes or safe deposition in landfill. The export of waste to landfill or for recycling is extensively regulated. We have also developed procedures for monitoring and following up on the receiving party’s processing operations to ensure that their waste processing is acceptable from a health and environmental perspective.

As there are no significant waste losses in the production processes at Boliden’s units, the waste Boliden generates is considered the same as waste that is either diverted or directed for disposal, as presented in the tables on page 40.

Each unit is responsible for reporting the waste they consider most significant in their waste streams. The waste indicators in the following table were established in 2021, hence no comparative data is available for 2020.

Each unit is responsible for reporting the waste they consider most significant in their waste streams. The waste indicators in the following table were established in 2021, hence no comparative data is available for 2020.

Mining and smelting operations generate residual waste consisting of waste rock, tailings, slag, and sludge. We extract and process several different minerals and metals that are potentially both toxic and environmentally harmful. For example, some of the tailings and waste rock generated are potentially acid generating, which requires adequate management to minimize the generation and release of acid rock drainage. There is considerable awareness of the importance of waste issues within the Boliden Group, and we conduct selective waste management, waste sorting, recycling of process residues and scrap, reporting procedures and ongoing waste R&D projects. Our waste streams are managed in accordance with the EU Directive on the Landfill of Waste and the Extractive Waste Directive. At Smelters, the quality of landfilled waste is analyzed frequently according to an approved monitoring program approved by authorities to ensure that all set criteria for landfilled waste (e.g. dissolution) are met. Progressive reclamation is applied where suitable, for example waste rock facilities are covered and re-vegetated progressively to minimize weathering and leaching. Our extractive waste is handled in accordance with all applicable environmental permits that specify how and where it may be stored and how it shall be covered and reclaimed.

We follow international guidelines on dam safety and we implement the GISTM as a member of the ICMM. We are responsible for operative and closed tailings facilities in Sweden, Finland and Ireland. Boliden is also responsible for various dams used for water management. The GISTM will be implemented not only at mines but also at Boliden smelters that have landfills with dams, that could be under the scope of this standard (Kokkola and Harjavalta).

In underground mining operations, tailings and waste rock are used as backfill, as reinforcement and to optimize the mineral extraction process. About 5% of the tailings and 30% of our waste rock were reused in 2022. This decreased the number of tailings and amount of waste rock that needed to be deposited above ground. Selective waste rock management makes it possible to use a proportion of the waste rock by complying with set criteria to allow it to be used as construction materials, both on and off site. Tailings and waste rock used for backfilling are not considered to be waste and are not reported as such.

1) Numbers for construction and backfilling were separated in 2021.

2) Corrected calculations.

At open pit mines, we selectively manage overburden and topsoil, which are stored separately and used in the reclamation of the different sites.

The Rönnskär smelter has a leaching plant that enables waste materials that have been stored at the site since 1975 to be reprocessed. It will eventually decrease the 460,000 metric tons of waste materials currently stored on site to 220,000 metric tons. The remaining waste will be stored in an underground repository located under the Rönnskär smelter plant. The deposition of waste material in the repository continued in 2022. This is a globally unique solution and is the only place in the world where a deep underground repository has been constructed at a smelter site.

Boliden’s operations generate 1.2 million metric tons of hazardous and non-hazardous waste, which is sorted at the respective sites and collected by authorized waste management companies for further processing or final deposition according to the applicable legis