Tag Archives: Sustainable Sand

Vale brings second Sustainable Sand operation online

Vale has added a second site to its Sustainable Sand efforts, having started industrial-scale production of the by-product at its Viga mine in Congonhas, Minas Gerais, Brazil.

The operation has the capacity to process 200,000 t/y of sand, with 80,000 t slated for 2022 and 185,000 t in 2023.

Obtained from the treatment of iron ore tailings, Sustainable Sand is one of the company’s initiatives to reduce the use of dams in its operations in Minas Gerais. The material can replace natural sand, extracted from river beds, with a wide application in the civil construction market.

Jean Menezes, Operations Manager of the Viga mine plant, said: “Due to the geological characteristics of the mine and the mineral processing technology applied, we developed a coarser sand, with low presence of fine particles in the material, and high purity content, having in its composition between 89% and 98% silica and less than 7% iron.”

The company is already conducting tests of the material with concrete and mortar producers in the Southeast Region, with the Sustainable Sand flowing between the production site and the clients by rail, taking advantage of the existing logistics at the site.

The Viga mine is Vale’s second unit to manufacture Sustainable Sand on an industrial scale, following the same quality controls as for iron ore production. The first was the Brucutu mine, in São Gonçalo do Rio Abaixo, Minas Gerais, which processed 250,000 t of the material last year. The company’s projection is to produce 1 Mt of Sustainable Sand this year, before doubling the volume in 2023.

Each tonne of sand produced represents one tonne less of tailings being placed in piles or dams, Vale says.

Another initiative adopted by Vale to reduce its dependence on dams, and which also favours the production of Sustainable Sand at the mines, is the tailings filtration system. The technology reduces the moisture of the tailings, enabling both dry stacking of the material and the manufacture of sand for the market. Four tailings filtration plants have been implemented in Minas Gerais – one in the Vargem Grande Complex (in 2021), two in the Itabira Complex (between 2021 and 2022) and one in the Brucutu Mine (in 2022).

Vale has already invested more than BRL50 million ($9.7 million) and established partnerships with more than 40 organisations, including universities, research centres and domestic and foreign companies to study applications for material from iron ore processing. The objective is to make Vale’s operations safer and more sustainable, promoting the circular economy and benefiting society.

In March this year, the first road in Brazil to use Vale’s Sustainable Sand in all four layers of pavement was inaugurated. The 425-m-long track at Cauê mine, in Itabira, will be monitored for two years with 96 pressure, temperature, deformation and humidity sensors. Tests carried out during five years in the laboratory indicated that the increase in useful life is of the order of 50% and the cost reduction is 20% when compared with materials more commonly used for road construction, such as sand extracted from the environment. In addition, each kilometer of pavement can consume up to 7,000 t of tailings.

In April 2022, a study released by the University of Queensland (UQ), through its Sustainable Minerals Institute (SMI), the University of Geneva (Unige) and the United Nations Environment Program (UNEP) pointed out that the sand from the iron ore production process, called “ore-sand”, can contribute to solve two important environmental issues by reducing both the extraction of natural sand from the environment and the generation of mining waste.

Vale’s Sustainable Sand to impact tailings generation plans

The University of Queensland – through its Sustainable Minerals Institute (SMI) – and the University of Geneva recently released a report indicating that sand from the iron ore production process may contribute to solving two important environmental issues by reducing sand extracted from the natural environment and cutting the generation of mining tailings.

One of the big contributors to this report was Vale, which, itself, has developed Sustainable Sand, a co-product of iron ore processing that, instead of being disposed in piles and dams, is now being processed and transformed into a product, following the same quality controls as in its iron ore production.

This year, Vale will allocate around 1 Mt of sand between sales and donations for use in civil construction and tests in pavement, among other uses. Much of this is set to come from its Brucutu mine in Minas Gerais.

IM put some questions to Bruno Batista, Engineer at Brucutu mine, and Fabiano Carvalho Filho, Executive Manager for Ferrous Business Development, to find out more about the company’s plans for Sustainable Sand.

IM: How has Vale changed its operational practices at mine sites to make the most of the Sustainable Sand process? For instance, have mine plans or layouts been adapted to ensure it is easier to obtain and process this material?

BB: First of all, Vale has done deep research about the technical potential for iron ore tailings and the mineral processing to obtain sand from them. Despite sand generation sharing existing assets deployed for the exploration of iron ore, it is important to highlight that Vale had to obtain the mineral and environmental licence to produce, sell and donate sand. The use of new technologies for greater recovery of iron ore have been installed in our operations and, as a result, we will have better quality sandy tailings. In some cases, it was necessary to implement new stages of concentration, classification and filtration so that it was possible to produce quality sand that met market requirements. We did change the quality control, treating sand as a product, with specification, daily analysis and process adjustment in order to meet it.

IM: I think it was 250,000 t of sand set aside for sale or donation to be used in concrete, mortar, cement and road pavement last year, another 1 Mt/y this year and 2 Mt/y in 2023. What are the longer-term goals for Sustainable Sand and – at the same time – how is this impacting your tailings handling plans?

BB: Vale’s objective is to enable more sustainable mining. The figures you mention are correct. Our pace of production in the long term will depend upon several factors, such as logistics capacity and market availability. Sustainable Sand is one of the initiatives to reduce the generation of tailings. Other initiatives are being developed as such as dry concentration and tailings filtering.

IM: Is there a balance to be had here with using sand for dry-stacked tailings purposes – increasing the stability of your tailings infrastructure – and donating/selling it for other uses? Is this what could potentially put a ‘cap’ on your Sustainable Sand production for sale/donation?

BB: Coarse tailings are destined for sand production and also for dry stacking. To increase more significantly sand production there are some challenges, such as logistics capacity and market availability. Vale is advancing and we should forecast a production of 2 Mt in 2023. We are also studying applications for the ultrafine material, so we would need less coarse tailings for dry stacking.

IM: Aside from the 425-m-long road at the Cauê mine, in Itabira, and the Pico Block Factory, what other applications will the sand have?

FCF: At the moment, the focus is on the construction market, mainly concrete, mortar and cement, as it has the largest production scale and is already being sold to by Vale, and road pavement, in which we are advancing our research. Vale has a portfolio of more than 20 initiatives for the use of tailings from mining. These initiatives are the result of partnerships with universities, research centres and other companies. These are initiatives that encompass several industries, focused on civil construction, chemical industry and automotive, among others. The initiatives are at different stages of maturity and the future of the projects still depends on progress in the research being carried out.

IM: Sand is the planet’s most mined material, so what does Vale plan to do with this Sustainable Sand process to reduce the environmental impact of the wider mining industry?

FCF: Vale’s objective is to enable more sustainable mining. The UNEP report (2022), in which the Vale Sand Case has been studied, shows that substituting naturally-sourced sand with ore sand (sand from iron ore tailings) could potentially lead to net reductions in carbon emissions generated during sand production. The substitution of marine or riverine sand for ore sand could also lead to a reduction in ecosystem damage. Besides that, Vale Sand is a certified product, which can contribute to this particular industry.

IM: Is there potential for other iron ore mining companies using this process to reduce their own tailings generation? the process been patented?

FCF: Iron ore tailings beneficiation demands investments and technology; there are patents involved in the development of other products derived from the sand.

Vale’s Sustainable Sand wins plaudits as miner starts construction on ‘green pig iron’ plant

Vale’s sustainability efforts are continuing to be displayed to the rest of the industry, with the major miner making a significant contribution to a report on the sustainable use of sand in mining and starting construction on a ‘green pig iron’ production facility in Brazil.

On the former, the University of Queensland, through its Sustainable Minerals Institute (SMI), and the University of Geneva, recently released a report indicating that sand from the ore production process may contribute to solving two important environmental issues by reducing sand extracted from the natural environment and the mining tailings generation. Vale contributed to the report and facilitated the sampling of its Sustainable Sand produced at the Brucutu mine in Minas Gerais for an independent analysis.

Vale’s Sustainable Sand is a co-product of iron ore processing. Based on adjustments in the operation, the sandy material, previously disposed in piles and dams, is now processed and transformed into a product, following the same quality controls as in the iron ore production. This year, Vale will allocate around 1 Mt of sand, between sales and donations, for use in civil construction and tests in pavement, among other uses.

The company came up with the process after seven years of research and investment of about BRL50 million ($8.9 million), it said last year.

The SMI report carried out by the universities, ‘Ore-sand: A potential new solution to the mining tailings and global sand sustainability crises’, investigated whether sand from ore processing, described by the term “ore-sand”, could become a sustainable source of sand and at the same time reduce the volume of tailings generated by mining.

Material characterisation results from the report indicate that the sampled material is inert and non-toxic, and can be suitable for certain applications, either on its own or as a part of a blend, such as with coarser sand, in order to meet specific grading requirements. Separating and repurposing these sand-like materials before they are added to the waste stream would not only significantly reduce the volume of waste being generated but could also create a responsible source of sand, Vale said.

The report found that, from a technical perspective, sand from iron ore operations can be a direct substitute for sand extracted from the environment in brick making, pavement, in embankments and cement manufacturing. When mixed with coarser sand and other aggregates, it can be used in the production of concrete and mortar, drainage and soil improvement, and water treatment.

The life cycle assessment of “ore-sand”, based on the case of Vale’s Sustainable Sand, also shows that this material has the potential to present lower net carbon emissions during its production when compared with sand extracted from the environment. However, to get a better idea of the potential of this reduction, it is necessary to carry out an assessment of the product’s transport stage, which was not covered in this report, Vale added.

Last week, Vale inaugurated the first road in Brazil using “ore-sand” in all four layers of the pavement. The 425-m-long road at the Cauê mine, in Itabira, will be monitored for two years with pressure, temperature, deformation and humidity sensors. Tests carried out during five years in the laboratory showed an increase in lifespan of around 50% and a cost reduction of 20% when compared with the most commonly used materials for road construction, such as sand extracted from the environment, Vale said. In addition, each kilometre of pavement can consume up to 7,000 t of tailings.

‘Green pig iron’

Earlier in the month, Vale and the Government of the State of Pará held an event to mark the beginning of the construction works of the first commercial plant of Tecnored in Brazil. Tecnored’s technology allows the production of so-called ‘green pig iron’, by replacing metallurgical coal with biomass, thus reducing carbon emissions and contributing to the decarbonisation of the steel industry.

The unit will have an initial capacity to produce 250,000 t/y of green pig iron, with the possibility of reaching 500,000 t/y in the future. The start-up is scheduled for 2025 with an estimated investment of approximately BRL1.6 billion ($342 million).

Vale’s President, Eduardo Bartolomeo, said the implementation of Tecnored represents an important step in the transformation of mining, contributing to making the process chain increasingly sustainable.

“The Tecnored project is of great importance to Vale and to the region and will bring gains in competitiveness, environmental sustainability and development for the region,” he said.

Eduardo Bartolomeo greets the Governor of Pará, Hélder Barbalho, during the launch ceremony for the Tecnored commercial plant

In the implementation phase of the project, which will work in the area of the old Ferro-Gusa Carajás, in the industrial district of the municipality, it is estimated that around 2,000 jobs will be generated at the peak of works. In the operational phase, about 400 direct and indirect jobs should be created, according to progress and engineering studies.

The Tecnored furnace is much smaller in size than a traditional steel blast furnace and is flexible in its use of raw materials, which can range from iron ore fines and steel residues to dam sludge, Vale said.

As fuel, the furnace can be fed by carbonised biomass, such as sugarcane bagasse and eucalyptus. Both are transformed into briquettes (small compact blocks) and deposited in the furnace, generating green pig iron. The furnace also allows the use of thermal coal itself as fuel. In this first instance, fossil fuels will be used to evaluate the performance of the plant, Vale explained.

Leonardo Caputo, Tecnored’s CEO, said: “Gradually, we are going to replace coal with carbonised biomass until we reach the goal of 100% biomass.”

The flexibility in the use of fuels in the furnace allows operating costs to be reduced by up to 15% compared with a traditional blast furnace, Vale claims.

Developed over the last 35 years, Tecnored’s technology also eliminates the coke furnaces and sintering processes: stages prior to the production of steel in the steel mill that are intensive in their greenhouse gas (GHG) emissions. This also reduces capital costs by up to 15%, according to Vale.

In addition, the plant is self-sustaining in terms of energy efficiency, with all the process gas reused and a portion used for energy co-generation, the company said. The slag by-product can be used as raw material in the cement industry.

Currently, Vale maintains a demonstration plant of this technology in Pindamonhangaba, with a rated capacity of 75,000 t/y, where tests were carried out to develop the technology and technical and economic feasibility.

Tecnored’s commercial plant in Marabá is part of Vale’s effort to offer its steelmaking customers technological solutions to help decarbonise their production processes.

In 2020, the company assumed the goal of reducing Scope 3 net emissions by 15% by 2035. Of this total, the company will contribute up to 25% through a high-quality products portfolio and technological solutions, including green pig iron. Today, the steel industry represents 94% of Vale’s Scope 3 emissions.

Vale also announced the goal achieving net zero Scope 1 and 2 emissions by 2050 and, to that end, it is investing between $4-6 billion, as well as committing to recover and protect another 500,000 ha of forest in Brazil.