Material topic
Waste
GRI 103-1, 103-2, 103-3 SDG 9.4, 12.4, 12.5

17 2017 data recalculated as a result of adjustments in calculation form GRI 102-48

Aware of our responsibility for solid waste generation impacts, we go beyond the regulatory requirements, investing in research and development of new technologies that allow us to reduce the amount of waste generated or turn them into secondary products for use in other industries.

One of the focal points of the research in the year was the project to recover barite as a residue from the zinc mining process in Cerro Lindo. Tests carried out in 2018 resulted in the production of high purity and density barite; we are now planning to build a processing plant in 2019 (more information in the Innovation and Technology chapter).

We positioned our Juiz de Fora plant as a materials recycler. Currently, 24% of the production derives from secondary (recycled) materials, composed of PAE (19.8%), brass oxide (0.3%), imported Waelz oxide (0.3%), batteries (0.02%) and low-grade silicate (0.44%). Our strategic mandate foresees raising this percentage to 33% by 2023 and 40% by 2025.

The Morro Agudo mine’s project for agricultural limestone production was continued, with a 22% increase in the output of Zincal200, created from what was previously the residue generated in the beneficiation process for zinc deposit dams. For production of Zincal200, we made modifications in the process, making it possible to produce a zinc-rich agricultural corrective. Thus, in addition to correcting the acidity, our limestone also increases soil productivity thanks to the presence of zinc in the composition. This by-product now represents revenue of US$ 7.4 million (or 12% of unit’s output). But its biggest benefit is the fact that it eliminates the need to build new containment structures, which means both environmental and economic gains. GRI 102-2

In Vazante, we entered into a partnership with the Edital Senai Inovação to transform residual cadmium and lead from the operation into secondary products through leaching, calcination and flotation routes, or through a combination of transformation tracks. The tests are expected to be completed in the first half of 2019.

And in the Mining Lab 2 program, we also selected a startup with the focus on evaluating the potential of smelter tailings conversion into vitroceramic products. This project is in the initial (bench) phase and will be continued throughout 2019.

In 2018, our operations generated a total of 19.2 million tonnes of mining and smelting waste, of which 67.7% was hazardous and 32.3% was non-hazardous – an increase of 14.1% over the results of 2017. GRI MM3

Battery recycling SDG 9.4

About 700 million batteries are consumed annually in Brazil, which corresponds to 2,100 tonnes of zinc metal. The incorrect disposal of this material is harmful to the environment and to people’s health and any initiative for recovery of materials contained in the batteries and the correct destination of the tailings is welcome.

We have received at our unit in Juiz de Fora the batteries collected by Green Electron – Manager for Reverse Logistics of Electrical and Electronic Equipment, founded in 2016 by the Brazilian Association of the National Electronics and Electrical Industry (Abinee).

Our consumption is still restricted, with treatment of only 1% of the zinc contained in piles (or 76 tonnes). However, we have been studying ways to extend the use of batteries in our production. By 2019, our goal is to double our funding to recycle about 200 tonnes of batteries. The slag from the furnace where the pile is processed is destined for the cement industry, closing the recycling cycle.

Waste volume (thousand tonnes) GRI 306-2, MM3

18 Revised 2017 data due to adjustments in calculation form. GRI 102-48

Management of dams and tailings deposits

The management of dams and tailings deposits is one of the main risks associated with the mining activity. In order to control and monitor our 46 dams and tailings deposits (22 in Brazil and 24 in Peru), we apply guidelines from the International Commission on Large Dams.

Currently, we use three methods of waste disposal in our operations: dams, dry stacking and return to the mine, filling the spaces from which the mineral was withdrawn (backfill). For all methods of control and monitoring we follow the laws in force in each country where we operate.

Some operations may combine one or more disposal methods. In the Atacocha, El Porvenir and Cerro Lindo units in Peru, we adopted the backfill system, whereby 38% of the wastes return to the Pasco Complex mines (Atacocha and El Porvenir) and 48.7% to the Cerro Lindo mine, in which part of the residue is filtered, separating water and solids. The water is recirculated and the filtered waste is sent to the piles to be compacted. This same model is being considered in new projects in Brazil (Aripuanã and Caçapava do Sul).

We started the filtered tailings disposal project at the Vazante mine, which was granted an installation license in 2017. With an investment of US$ 44 million, by 2020, the unit will use the dry stacking method, which reduces environmental impacts and risks to the operation.

Dam management is one of the topics included in our business risk management processes and regularly discussed at executive meetings, where reports are presented on the stability of these structures. We have processes and procedures that form the Integrated Dam Management System (SIGBar) and an Integrated Deposits Management System (SIGDep). These two systems are composed of 12 modules that establish rules and measures for regular monitoring actions, from which we control all the structures. SIGBar sets out guidelines for document management, monitoring, evaluation, risk analysis, compliance with standards and legislation, training of personnel, operation of structures and other provisions.

This work is permanently monitored by an independent company, which receives data from biweekly inspections and monthly consolidates data from all monitoring operations to issue stability reports. In 2018, the structures that were inactive were inserted into SIGBar so that we could carry out the monitoring in an effective and safe way.

In 2019, we plan to install the siren system in all units in Brazil and Peru. The amount of sirens required in each locality depends on the topography of the site and the self-rescue zone characterized in each facility’s Emergency Response Plan (ERP). After the installation of the sirens, simulations will be carried out with the local communities.