INNOVATIVE STUDY OF IRON TAILINGS OCCURRENCE IN A BRAZILIAN DAM: CONTRIBUTION TO THE CIRCULAR ECONOMY *V.F. Navarro Torres1, C. Dalmiro2, A. Sampaio2, C.A. Ortiz3, C.E.R. Aquino1, V.D. Pazmiño3 1Vale Institute of Technology, Brazil, (*Presenting author: vidal.torres@itv.org) 2Vale S.A., Brazil 3INK Engineering, Brazil & EcuaCorriente S.A. ABSTRACT The objective of the study was to generate detailed knowledge of the occurrence of sediments deposited in the Gelado tailings dam of an iron mine located in the State of Pará, Brazil, for optimal planning and selective mining using a dredging system, in order to reclaim the tailings and thereby contribute to the Circular Economy. A geostatistical method was applied, based on drilling campaigns carried out in 2001 and 2010, totaling 306 drillholes and 801 samples with grades of Fe, SiO₂, P, Al₂O₃, Mn, CaO, MgO, TiO₂, and LOI. The samples were statistically evaluated and validated for construction of both the 3D geological model and the estimation model. Geological body modeling was performed using an implicit method based on interpretation and adjustments of vertical sections, considering sample locations and the contents of the chemical components of interest. In addition, the original (pre-deposition) topography was considered to determine the base and limits of the deposit, as well as the current topography. Ordinary kriging was chosen to estimate the grades of the chemical components and the grain-size fractions described in the samples. The kriged model was validated through two analyses: a comparison of means and a drift analysis. The results show that Fe grades ≥ 65% occur on the west side and from 63% to 65% in southernmost portion, decreasing gradually eastward, ranging from 56% to 62%. It was also possible to characterize an inverse correlation between Fe and SiO₂ and between Fe and Al2O3, as well as the grain-size distribution of sediments—coarser material occurs near the tailings discharge, decreasing gradually with distance. Finally, the estimated resources total 287.14 Mt, with an average grade of 63.89% Fe, 2.06% SiO2, 0.06% P, 2.31% Al2O3, 0.83% Mn, 0.016% CaO, 0.06% MgO and 0.16% TiO2. KEYWORDS Tailings from dams, iron, reuse, circular economy, sustainability. 1. INTRODUCTION As the leading Circular Economy initiatives at Vale S.A. are related to the reuse of tailings and the use of waste rock from ore processing (https://vale.com/pt/esg/mineracao-circular).
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