Soil physical properties of high mountain fields under bauxite mining

Abstract

Mining contributes to the life quality of contemporary society, but can generate significant impacts, these being mitigated due to environmental controls adopted. This study aimed to characterize soil physical properties in high-altitude areas affected by bauxite mining, and to edaphic factors responses to restoration techniques used to recover mined areas in Poços de Caldas plateau, MG, Brazil. The experiment used 3 randomized block design involving within 2 treatments (before mining intervention and after environmental recovery), and 4 replicates (N=24). In each treatment, soil samples with deformed structures were determined: granulometry, water-dispersible clay content, flocculation index, particle density, stoniness level, water aggregate stability, and organic matter contend. Soil samples with preserved structures were used to determine soil density and the total volume of pores, macropores, and micropores. Homogenization of stoniness between soil layers as a result of soil mobilization was observed after the mined area recovery. Stoniness decreased in 0.10-0.20 m layer after recovery, but was similar in the 0-0.10 m layer in before and after samples. The recovery techniques restored organic matter levels to pre-mining levels. However, changes in soil, including an increase in soil flocculation degree and a decrease in water-dispersible clays, were still apparent post-recovery. Furthermore, mining operations caused structural changes to the superficial layer of soil, as demonstrated by an increase in soil density and a decrease in total porosity and macroporosity. Decreases in the water stability of aggregates were observed after mining operations.Index terms: Environmental recovery, physical soil quality, soil recovery. RESUMOA mineração contribui para a qualidade de vida da sociedade contemporânea, porém pode gerar impactos significativos, sendo esses mitigados em função dos controles ambientais adotados. Neste trabalho objetivou-se caracterizar as propriedades físicas do solo, mediante a influência de empreendimentos minerários, avaliando as respostas dos atributos edáficos frente às técnicas utilizadas para a recuperação de áreas degradadas pela mineração de bauxita na região do planalto de Poços de Caldas, MG. O delineamento experimental foi concebido com 3 blocos casualizados, com 2 tratamentos (antes da intervenção minerária e depois da recuperação ambiental), e 4 repetições (N=24). Em cada situação, por meio das amostras com estruturas deformadas foram determinados: granulometria, argila dispersa em água, índice de floculação, densidade de partículas, índice de pedregosidade, estabilidade de agregados em água e teor total de matéria orgânica, por meio das amostras com estrutura preservada foram determinadas: densidade do solo, volume total de poros, macroporos e microporos. Após a recuperação da área minerada, ocorreu homogeneização da pedregosidade entre as camadas, decorrente do revolvimento e, consequentemente, da sua redução na camada de 0,10 a 0,20 m; os processos de recuperação da áre...

Iron ore mining areas and their reclamation in Minas Gerais State, Brazil: impacts on soil physical properties

“…Postmining areas did not differ for the soil properties AWC INFL and θ INFL , but for AWC, ER was smaller. After post-mining reclamation process, changes occur in soil physical properties related to pore size distribution, basically reducing macropores and increasing micropores, which occur few [20]. However, our results contrast with Barros et al [20], since NR improved soil aeration function (Table 3).…”

“…After post-mining reclamation process, changes occur in soil physical properties related to pore size distribution, basically reducing macropores and increasing micropores, which occur few [20]. However, our results contrast with Barros et al [20], since NR improved soil aeration function (Table 3). This finding suggests that reclamation process for long years leads to improvements in soil physical quality in iron ore mining areas.…”

“…Pd basically influences soil aggregation attributes as shown above. However, stoniness had more impact on soil properties because it reflects mining reclamation process [20] and therefore is essential in interpreting soil functions affected by mining.…”

“…Given the importance of the iron ore mining activity in the Minas Gerais State and the soil physical quality in the reclamation of these environments, studies need to be conducted to evaluate its effects on soil physical quality. Studies focusing on the soil physical quality recovery of high-altitude mining fields are scarce [20]. This is particularly the case with iron ore areas in tropical soils.…”

Growth Response of Abaca (Musa textilis Nee) in Abandoned Mine Soil Amended with Oil Palm Residues

“…As claimed by de Barros et al (2013), the environmental effects of mining activities can be mitigated using appropriate environmental controls and ecological restoration techniques. In other countries like Indonesia, integrated spatial planning of mined land was found to be potentially effective in providing environmental benefits, economic sustainability, and social acceptability (Kodir et al, 2017).…”