Learn how the circular economy is transforming mining tailings and waste rock into new opportunities for the mining industry.
The reuse of mining waste and tailings has become a central issue on the mining sector’s sustainability agenda. This trend stems both from advances in the environmental and mining legal and regulatory framework and from the incorporation of principles related to the circular economy, technological innovation, and social and environmental responsibility.
According to the National Solid Waste Policy (PNRS—Law No. 12,305/2010), solid waste is any material, substance, or object resulting from human activities that is discarded but can still have economic value through reuse, recycling, recovery, or energy recovery. Tailings, on the other hand, are a specific category within solid waste: they are materials that, after all technically and economically viable options for treatment or reuse have been exhausted, must be sent for environmentally sound final disposal, such as in landfills or containment structures.
In the mining sector, ANM Resolution No. 85/2021 defines “tailings” as material removed during mining that lacks economic value for immediate mineral extraction but has not undergone a beneficiation process. Although traditionally viewed solely as a liability, tailings may have potential for alternative uses, particularly in the construction industry and infrastructure projects.
It is important to note that, in light of these definitions, tailings and waste rock may no longer be classified as environmental liabilities when they have a proven technical application and a consumer market, thereby qualifying as inputs, by-products, or co-products.
The PNRS distinguishes between reuse and recycling. Reuse consists of the direct use of the material, without significant transformation, for the same or another purpose (for example, the use of tailings in pavement layers or structural fill). Recycling, on the other hand, involves the physical, chemical, or biological transformation of waste or tailings, enabling their reintegration into the production chain, as occurs in the manufacture of artificial aggregates, bricks, blocks, cement, or raw materials for the ceramics industry.
In the context of mining, these practices contribute to:
In its 2025 Annual Sustainability Report, SAMARCO announced that it has been using sandy tailings—a byproduct of the iron ore processing—in the decommissioning work at the Germano Dam and in concrete production, and is also investing in eco-friendly paving projects using ultrafine tailings.
As reported by Samarco itself, 2025 was the best year since operations resumed, with a 45% utilization rate for tailings and waste rock. Of this volume, approximately 89% of the tailings filtered during processing was used in the decommissioning work on the dam and the pit at the Germano Complex in Minas Gerais. In addition, 15% of the waste rock generated was sold as marginal ore.
AngloGold Ashanti initiatives focus on repurposing waste rock and tailings for the construction industry, transforming them into coatings, paving materials, aggregates, and sustainable concrete. The company also reprocesses gold waste for metal recovery and produces iron briquettes, in addition to converting concentrates into sulfuric acid and producing agricultural limestone powder.
AngloAmerican initiatives, on the other hand, focus on the circular economy by transforming sandy tailings into interlocking blocks with 62% greater strength; the company has already paved rural roads with 2,500 metric tons of waste. Another strategic project reuses iron-nickel slag as aggregates for asphalt paving and fertilizers, with the goal of preventing the disposal of 17 million metric tons of material.
CBMM focuses its efforts on the circular economy through the recovery of refractory bricks for industrial reuse and the valorization of pyrochlore tailings. The company has developed processes to transform magnetic waste into iron ore and to utilize flotation tailings in the production of barite concentrate. These projects mitigate environmental liabilities, reduce CO2 emissions, and convert waste into valuable commercial inputs.
AMG Brasil promotes the circular economy by reprocessing tailings from old dams to produce spodumene concentrate and by converting aluminosilicate waste into geopolymer materials for the construction industry.
Rio Tinto’s initiative at the Kennecott operation in Utah, United States, involves reducing tailings generation by recovering tellurium from the anode slimes produced during copper refining—a material that was previously treated with reagents and sent for final disposal. The implementation of a dedicated tellurium circuit has enabled the production of copper telluride as a byproduct. In this way, the company transforms a waste stream into a source of economic and strategic value, since tellurium is used in technologies such as cadmium telluride solar panels, contributing to the circular economy, waste reduction, and the supply of critical minerals for the energy transition.
In Chile, Anglo American carried out a pilot project using slag from copper processing to produce paving blocks that were used in the restoration of a public space in Villa El Sol in Catemu. The pilot project used approximately 1 metric ton of copper slag to produce high-quality construction material. The project was supported by the Pontifical Catholic University of Valparaíso and demonstrated the use of mining tailings in civil construction.
Boston Metals developed Molten Oxide Electrolysis (MOE), a technology that enables the selective extraction of high-value metals—such as niobium, tantalum, and tin—from low-concentration tailings and slag. Boston Metals Brazil leads the commercial application of this sustainable solution.
Other Brazilian case studies can be found in the following IBRAM reports:
The Brazilian legal system has begun to incorporate direct incentives for the reuse of mineral waste. Article 44 of the National Solid Waste Policy (PNRS) allows municipalities, states, and the federal government to establish regulations for granting tax incentives to industries engaged in the reuse, treatment, and recycling of solid waste produced in Brazil.
Within the state of Minas Gerais, for example, Law No. 23,575/2020 authorizes a reduction or even a total exemption from the ICMS tax for the manufacture of construction products that use mining tailings or waste as raw materials. This policy brings the mining sector closer to the construction materials industry and strengthens local production chains based on the circular economy.
At the sectoral level, Federal Decree No. 9,406/2018 includes the economic utilization of mining tailings, waste, and byproducts as an operation that is an integral part of mining activities. Furthermore, ANM Resolution No. 85/2021 addresses the administrative procedures for the utilization of tailings and waste rock.
Chile, for example, has also been amending its legislative framework to encourage the reuse of tailings. Decree 46, published in February 2026, establishes the health and safety requirements to permit the use of copper slag as artificial sand in Chilean construction.
In the European Union, Regulation (EU) 2024/1252 establishes a strategy to increase circularity and supply security within the bloc by transforming mining waste into valuable sources of secondary raw materials. To this end, it requires mining companies to conduct economic feasibility studies on the potential for recovering critical minerals. At the same time, Member States must create, by 2027, public databases on closed or abandoned facilities, in addition to adopting measures to reduce legal barriers and implement risk-sharing mechanisms and support for innovation. The ultimate goal is to economically revitalize historic mining regions and reduce Europe’s dependence on foreign imports.
As seen, legislators and regulatory bodies are seeking to encourage the reuse of mining tailings and waste rock, promoting the circular economy through economic incentives and regulations governing such reuse. However, although the legal frameworks have helped expand opportunities for the reuse of tailings and waste rock, their success must be continuously evaluated, taking into account the results actually achieved in terms of reducing environmental liabilities, generating economic value, and integrating the principles of the circular economy into the mining production chain.
These initiatives are directly aligned with Sustainable Development Goal 12 (SDG 12), which addresses responsible consumption and production, promoting the reduction of waste generation through prevention, recycling, and reuse. At the sectoral level, they also align with Target 5.9—“Promote sustainable production in the mining sector”—established by the 2030 National Mining Plan, which encourages innovation, the reduction of environmental liabilities, and the full utilization of mineral resources.
In practical terms, the main challenges for recycling mining tailings can be summarized under three categories:
Market and governance—market acceptance and logistics.
Overcoming these challenges is essential to transforming tailings into economic assets, aligning the mining sector with the principles of the circular economy, SDG 12, and the goal of sustainable mineral production established by the 2030 National Mining Plan.
The reuse of mining waste, tailings, and waste rock represents a paradigm shift: from an approach based solely on final disposal to an integrated approach that adds value to materials previously considered to have no economic use. With legal support, tax incentives, funding for innovation, and alignment with national and international public policies, the mining sector has the opportunity to move toward more efficient, safe, and sustainable production models, generating long-term environmental, social, and economic benefits.