Mapping Geochemical Anomalies Through Principal Components Analysis in BIF Mines: An Approach Referring to the Bonito Mine, Northeastern Brazil

Fonteles, Helano Regis da Nóbrega; Pereira, Henrique Garcia; Rocha, C.S.A.; Veríssimo, César Ulisses Vieira

doi:10.1007/978-3-030-01575-6_59

Cited by 1 publication

(2 citation statements)

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“…Geociênc., 2022;45:40955 Group, described by Angelim, Medeiros and Nesi (2006) as a metasedimentary sequence formed by the following units: Serra dos Quintos Formation (BIFs, marble, ferruginous quartzite, amphibolite, and schist), Jucurutu Formation (primarily paragneiss, marble, quartzite, iron formations and metaconglomerate), Equador Formation (muscovitequartzite) and Seridó Formation (feldspathic mica schist) (Figure 2). The BIF rocks of the Serra dos Quintos Formation gather an assemblage of itabirites (proto-iron ore types) previously studied by Barbosa (2013), Fonteles et al (2019a), Fonteles, Pereira and Veríssimo (2019b) and Fonteles et al (2020).…”

Section: Lithostratigraphymentioning

confidence: 99%

“…The study area is located at the Bonito mine, Northeastern Brazil (Figure 1), where low-grade iron ore is constrained by the banded iron formations (itabirites), which were previously studied by Barbosa (2013), Fonteles et al (2019a) and Fonteles et al (2020). The regional mapping works by Van Schmus et al (2003), and Angelim, Medeiros and Nesi (2006) recognized the BIF rocks as a relevant lithotype in the Serra dos Quintos Formation owing to their geological significance.…”

Section: Introductionmentioning

confidence: 99%

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Geostatistical Mapping of Folded Itabiritic Rocks of the Bonito Mine, Northeastern Brazil

Fonteles¹,

Veríssimo

2022

Anu. Inst. Geociênc.

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Geological modeling is the primary task of any exploratory geological investigation, and it is performed even during the mine development. In the study area, the Serra dos Quintos Formation hosts banded iron formations represented by assorted itabirites. The database used in this work was exploited from a geological databank which was structured to gather data and information depicted from an exhaustive exploratory drilling program. A survey was performed throughout the entire databank to collect the available thickness data values (measured in meters) from drill core logs that intersected the itabirite. Since structural heterogeneities can occur within these rocks, this study aims to identify such features. Geostatistical estimation and simulation methods were employed to map folded itabiritic beds based on thickness data accurately. Kriging estimators are often used for practical reasons; however, sometimes, the estimates can be smoothed and do not represent the entire original data range. Simulation algorithms can yield several stochastic images, but local accuracy cannot always be guaranteed. Simulated annealing was performed by adjusting the global statistics and preserving the local accuracy. We demonstrated that the banded iron formations’ thicker areas might correspond to the antiform fold as the dominant tectonic feature in the study area. Finally, we show that the simulated thickness map discloses the thicker mineralized spots. Meanwhile, the thinner ones may unveil intrinsic structural heterogeneities mainly observed at the limbs of the Bonito fold, where intensive deformation within the itabiritic layer was higher than expected. Concerning the mining issues, information obtained from the simulated thickness map could provide ancillary data to improve mining planning in the study area.

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Section: Lithostratigraphymentioning

confidence: 99%