The study shows that adding sand products extracted from iron ore tailings to road laying has both environmental and economic benefits.
A study conducted by Vale in collaboration with the Ita Juba Federal University (UNIFEI) in Minas Gerais, Brazil, over the past five years shows that Vale's sustainable sand products (obtained from the iron ore production process in Minas Gerais) can be used for road laying. Laboratory tests show that compared with roads paved with only traditional materials such as gravel, soil and sand, adding sand products extracted from iron ore tailings to each paving layer can prolong road life by 50 per cent and reduce road laying costs by 20 per cent. Vale's sustainable sand products have been successfully applied to the construction industry, making the company's operations safer because it can reduce the amount of tailings disposed of. At the same time, it can replace the sand in nature. Sand is the most exploited natural resource in the world after water.
The next step of the study is to monitor a new experimental road laid in the Cau ê mining area of Itabila City, so as to demonstrate the conclusions of the study. "this is the first road to be paved with sustainable sand products, and we are monitoring it in all directions with instruments. The road is 425 meters long and has four paving layers, each with different proportions of Vale sustainable sand products. We use 96 sensors to monitor the pressure, temperature, strain and humidity of the road, which will provide performance data on the road structure when heavy vehicles continue to pass through and in real weather conditions. The Ita Juba Federal University Itabila Campus and the Federal University of Rio de Janeiro will conduct a two-year analysis of this information, which will also be shared with the Transport Institute (IPR) of the National Ministry of Transport Infrastructure (DNIT) to create technology combinations and standardize methods. " Rodrigo Dutra Amaral (Rodrigo Dutra Amaral), executive manager of Vale's environmental permits.
Vale has invested more than 7.1 million reais in the research and development of sustainable sand products for road laying. Marina Dumont, Vale's business development manager, says this provides a good new business opportunity for the company and directly benefits the community. "We promote the development of circular economy by reusing tailings treated by stacking and mining dams in the past. Up to 7000 tons of tailings from the iron ore production process can be used per kilometer of road surface. In Minas Gerais alone, we have about 250000 kilometers of unpaved roads. "
Les Rezenda, Vale's engineer in charge of the research, said that sustainable sand products not only made the company's operations more sustainable, but also had an advantage over traditional paving materials: "with the addition of Vale's sustainable sand products, roads show better resistance to fatigue and permanent strain. Vale's sustainable sand products can reduce the use of petroleum asphalt cement by 6%, which is one of the most expensive materials in road paving. In addition, it can reduce the use of cement and lime. "
Vale has worked with a number of partners to seek certification for the use of sustainable sand products for road laying. Last year, Vale's sustainable sand products in concrete and mortar applications have been certified by a number of research institutions. After adjusting Minas Gerais' operations, Vale expects to sell or donate about 1 million tons of sustainable sand products this year and is expected to double by next year.
Vale has also taken other initiatives to reduce the use of tailings dams, such as the construction of four tailings pressure filtration plants, which contribute to the production of sand products. "the two tailings pressure filtration plants opened at the beginning of this year in the Kauai and Concei mines will boost the production of Itabila's sustainable sand products as they reduce the percentage of water in the tailings and allow the tailings to be stacked dry, increasing market interest in the product." Said Daniel Dach (Daniel Daher), executive manager of Vale's Itabila integrated operation area. The Grand Varren integrated operation area in New Lima has previously opened a tailings pressure filtration plant, while the Brukutu mining area in San Gonzalo-upon-Abishau will open a fourth tailings pressure filtration plant in the second quarter of this year, which are conducive to the reuse of tailings.
Production of sustainable sand products in Vale
Vale's sustainable sand products are by-products of iron ore production. After adjustments have been made to operations in Minas Gerais, sandy materials that were previously disposed of in the form of stacking or with mineral dams are processed and converted into commercial products and the production process follows the same quality control standards as iron ore production.
100% certified sand products from the iron ore processing process have high silicon content and low iron content, and have high chemical uniformity and particle size uniformity. These sand products are not dangerous because they are basically processed in a physical way, and the chemical composition of the material is not changed during the processing process.
Vale's sustainable sand products can be used to produce concrete, mortar, prefabricated parts, artifacts, and cement, as well as paving roads.
Invest in education and technology
The city of Itabila invests in education and technology as part of its economic diversification. Vale invested 3 million reais to support scientific research on the Itabila campus of the Federal University of Itajuba, including the purchase of equipment for laboratories majoring in mobile engineering, this major is recognized as the authority for road laying research in Minas Gerais.
Five professors from this institution and about 120 students have participated in the research on the use of sand products extracted from iron ore production for road laying, and they have submitted a patent application on this subject. and published more than 20 articles, papers and monographs.
"the model of research cooperation between Vale and the Federal University of Itaruba is extremely important for the development of scientific research in Brazil. The study of roads in the Kauai mine will provide data for the new national road laying dimensioning method (MeDiNa), developed by the Transportation Institute of the National Ministry of Transport Infrastructure and the Alberto Luis Coimbra Institute of Engineering (COPPE) of the Federal University of Rio de Janeiro. " Sergio Sonsim, professor and research coordinator at the Itabilla campus of the Itaraba Federal University, stressed.
