GPR Survey on an Iron Mining Area after the Collapse of the Tailings Dam I at the Córrego do Feijão Mine in Brumadinho-MG, Brazil

Abstract

This article shows the interesting results of a pioneer effort by IAG/USP researchers to use ground-penetrating radar (GPR) for humanitarian purposes, guiding the rescue of victims in the tragedy of Brumadinho. The tailings Dam I at the Córrego do Feijão iron ore mine, located in the Brumadinho complex, Minas Gerais State, Brazil, collapsed on 25 January 2019. About 11.7 million m3 of mining mud was spilled from the dam, burying bodies, equipment, structural buildings, buses, and cars along a length of 8.5 km up to the Paraopeba River. Additionally, the contaminated mud traveled more than 300 km along the bed of the Paraopeba River toward the São Francisco River. This work shows the results of a geophysical investigation using the GPR method 17 days after the event. To carry out the geophysical survey, an excavator was used for soil compaction. The data acquisition was performed on the tracks left by the excavator chain using SIR-4000 equipment and antennas of 200 and 270 MHz (GSSI). The GPR studies aimed to map bodies, structural buildings, and equipment buried in the mud. The location of the profiles followed preferably the edge of the slope due to the higher probability of finding buried bodies and objects. The GPR results allowed the detection of subsoil structures, such as concentrations of iron ore and accumulations of sand from the dam filter. The GPR was effective because the iron ore sludge in the mixing process became porous and the pores were filled with air, which provided penetration and reflection of the GPR electromagnetic waves up to a depth of 3.5 m. The results were surprising. Although no bodies or underground equipment were found, the results of this research served to eliminate the studied areas from future excavations, thus redirecting the rescue teams and optimizing the search process. These important results can serve as an additional motivation for the use of GPR in future humanitarian work in areas of tragedies.

Three-dimensional numerical simulation of mud flow from a tailing dam failure across complex terrain

“…The Córrego do Feijão iron mine complex, with two tailing dams, a cargo terminal, an administrative office and a small railway network for the transport of iron ore (Fig. 6a) (Porsani et al, 2019) that was conducted after the collapse, approximately 11.7 million m 3 of tailings were spilled from the dam, destroying office buildings, a railway bridge and a small community. Under the action of gravity, the tailing fluids traveled 9 km and eventually flowed into the Paraopeba River, the region's main river.…”

“…These related dam-break analyses can be divided into empirical models and numerical models. The empirical model predicts the volume of released tailings (V F ) and the run-out distance (D max ) by establishing a regression equation based on historical cases of collapse, dam height and the impounded volume of tailings (Rico et al, 2008a;Larrauri and Lall, 2018). However, owing to the difference in the actual state of the tailing reservoir and the surrounding environment, and without considering the rheological properties of the tailings such as the viscosity coefficient and yield stress (Martin et al, 2015), the predicted results may deviate greatly from the actual dam-break situation.…”

Modelling the Brumadinho tailings dam failure, the subsequent loss of life and how it could have been reduced

“…The last time the dam was raised was in 2013, and tailings disposal ceased in July 2016 (Robertson et al, 2019). The Brazilian Institute of Water Management of Mines and the National Mining Agency had evaluated and classified the dams probability of failure as being "low" (Porsani et al, 2019). At 12:28 pm local time on 25 January 2019, the Brumadinho tailings dam suffered a sudden failure, releasing a mudflow over 10 m deep which moved rapidly downstream (Robertson et al, 2019).…”

Next generation technology for utilization of alumina rich iron ore tailings in India

“…The unutilized mine waste may create environmentally damaging issues, placing more pressure on the mine operations (Rudramuniyappa 1997). Recent failure (25-January-2019) of Vale's Brumadinho iron ore tailings dam in Brazil creates a major overwhelming impact in the world iron ore trades and creates a big environmental issue (Fiscor 2019, Porsani, Jesus et al 2019. The key reason behind the tailing dam failure is continuous accumulation of waste minerals and poor maintenance of upstream dams as stated by International Commission on Large Dams (ICOLD) and the United Nations Environment Programme (UNEP) (Gray 1990).…”