Roots of Perennial Grasses in the Recovery of Soils Degraded by Coal Mining in Southern Brazil

After open coal mining, soils are “constructed”, which usually contain low levels and quality of organic matter (OM). Therefore, the use of plant species for revegetation and reclamation of degraded areas is essential. This study evaluated the distribution of carbon (C) in the chemical fractions as well as the chemical characteristics and humification degree of OM in a soil constructed after coal mining under cultivation of perennial grasses. The experiment was established in 2003 with the following treatments: Hemarthria altissima (T1), Paspalum notatum (T2), Cynodon dactilon (T3), Urochloa brizantha (T4), bare constructed soil (T5), and natural soil (T6). In 2009, soil samples were collected from the 0.00-0.03 m layer and the total organic carbon stock (TOC) and C stock in the chemical fractions: acid extract (CHCl), fulvic acid (CFA), humic acid (CHA), and humin (CHU) were determined. The humic acid (HA) fraction was characterized by infrared spectroscopy and the laser-induced fluorescence index (ILIF) of OM was also calculated. After six years, differences were only observed in the CHA stocks, which were highest in T1 (0.89 Mg ha-1) and T4 (1.06 Mg ha-1). The infrared spectra of HA in T1, T2 and T4 were similar to T6, with greater contribution of aliphatic organic compounds than in the other treatments. In this way, ILIF decreased in the sequence T5>T3>T4>T1>T2>T6, indicating higher OM humification in T3 and T5 and more labile OM in the other treatments. Consequently, the potential of OM quality recovery in the constructed soil was greatest in treatments T1 and T4.

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Soil compressibility and least limiting water range of a constructed soil under cover crops after coal mining in Southern Brazil

Soil and Tillage Research ◽

10.1016/j.still.2012.06.006 ◽

2012 ◽

Vol 124 ◽

pp. 190-195 ◽

Cited By ~ 18

Author(s):

Cláudia Liane Rodrigues de Lima ◽

Ezequiel Cesar Carvalho Miola ◽

Luis Carlos Timm ◽

Eloy Antonio Pauletto ◽

Alvaro Pires da Silva

Keyword(s):

Coal Mining ◽

Cover Crops ◽

Southern Brazil ◽

Soil Compressibility ◽

Least Limiting Water Range

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Leachability of major and minor elements from soils and sediments of an abandoned coal mining area in Southern Brazil

Environmental Monitoring and Assessment ◽

10.1007/s10661-015-4271-6 ◽

2015 ◽

Vol 187 (3) ◽

Cited By ~ 5

Author(s):

Maria Josefa Santos ◽

César Ricardo Teixeira Tarley ◽

Isabella Cunha ◽

Iago Zapelini ◽

Evgeny Galunin ◽

...

Keyword(s):

Coal Mining ◽

Mining Area ◽

Southern Brazil ◽

Coal Mining Area ◽

Minor Elements ◽

Soils And Sediments

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Valorization of iron pyrite from coal mining in southern Brazil

Journal of Environmental Chemical Engineering ◽

10.1016/j.jece.2019.102931 ◽

2019 ◽

Vol 7 (1) ◽

pp. 102931

Author(s):

Camila Machado de Oliveira ◽

Thuani Gesser Müller ◽

Leticia Patricio Ferreira ◽

Maria Alice Prado Cechinel ◽

Michael Peterson ◽

...

Keyword(s):

Coal Mining ◽

Iron Pyrite ◽

Southern Brazil

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Geochemistry of acid mine drainage from a coal mining area and processes controlling metal attenuation in stream waters, southern Brazil

Anais da Academia Brasileira de Ciências ◽

10.1590/0001-37652014113712 ◽

2014 ◽

Vol 86 (2) ◽

pp. 539-554 ◽

Cited By ~ 30

Author(s):

VERIDIANA P. CAMPANER ◽

WANILSON LUIZ-SILVA ◽

WILSON MACHADO

Keyword(s):

Chemical Composition ◽

Coal Mining ◽

Surface Waters ◽

Mine Drainage ◽

Mining Area ◽

Southern Brazil ◽

Acid Drainage ◽

Coal Mining Area ◽

Brazilian Legislation ◽

Ph Range

Acid drainage influence on the water and sediment quality was investigated in a coal mining area (southern Brazil). Mine drainage showed pH between 3.2 and 4.6 and elevated concentrations of sulfate, As and metals, of which, Fe, Mn and Zn exceeded the limits for the emission of effluents stated in the Brazilian legislation. Arsenic also exceeded the limit, but only slightly. Groundwater monitoring wells from active mines and tailings piles showed pH interval and chemical concentrations similar to those of mine drainage. However, the river and ground water samples of municipal public water supplies revealed a pH range from 7.2 to 7.5 and low chemical concentrations, although Cd concentration slightly exceeded the limit adopted by Brazilian legislation for groundwater. In general, surface waters showed large pH range (6 to 10.8), and changes caused by acid drainage in the chemical composition of these waters were not very significant. Locally, acid drainage seemed to have dissolved carbonate rocks present in the local stratigraphic sequence, attenuating the dispersion of metals and As. Stream sediments presented anomalies of these elements, which were strongly dependent on the proximity of tailings piles and abandoned mines. We found that precipitation processes in sediments and the dilution of dissolved phases were responsible for the attenuation of the concentrations of the metals and As in the acid drainage and river water mixing zone. In general, a larger influence of mining activities on the chemical composition of the surface waters and sediments was observed when enrichment factors in relation to regional background levels were used.

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Perennial grasses for recovery of the aggregation capacity of a reconstructed soil in a coal mining area in southern Brazil

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832014000100033 ◽

2014 ◽

Vol 38 (1) ◽

pp. 327-335 ◽

Cited By ~ 7

Author(s):

Lizete Stumpf ◽

Eloy Antonio Pauletto ◽

Flavia Fontana Fernandes ◽

Luis Eduardo Akiyoshi Sanches Suzuki ◽

Tiago Stumpf da Silva ◽

...

Keyword(s):

Coal Mining ◽

Cynodon Dactylon ◽

Mining Area ◽

Soil Aggregation ◽

Perennial Grasses ◽

Natural Soil ◽

Heavy Machinery ◽

Coal Mining Area ◽

Hemarthria Altissima ◽

Reconstructed Soil

The construction of a soil after surface coal mining involves heavy machinery traffic during the topographic regeneration of the area, resulting in compaction of the relocated soil layers. This leads to problems with water infiltration and redistribution along the new profile, causing water erosion and consequently hampering the revegetation of the reconstructed soil. The planting of species useful in the process of soil decompaction is a promising strategy for the recovery of the soil structural quality. This study investigated the influence of different perennial grasses on the recovery of reconstructed soil aggregation in a coal mining area of the Companhia Riograndense de Mineração, located in Candiota-RS, which were planted in September/October 2007. The treatments consisted of planting: T1- Cynodon dactylon cv vaquero; T2 - Urochloa brizantha; T3 - Panicum maximun; T4 - Urochloa humidicola; T5 - Hemarthria altissima; T6 - Cynodon dactylon cv tifton 85. Bare reconstructed soil, adjacent to the experimental area, was used as control treatment (T7) and natural soil adjacent to the mining area covered with native vegetation was used as reference area (T8). Disturbed and undisturbed soil samples were collected in October/2009 (layers 0.00-0.05 and 0.10-0.15 m) to determine the percentage of macro- and microaggregates, mean weight diameter (MWD) of aggregates, organic matter content, bulk density, and macro- and microporosity. The lower values of macroaggregates and MWD in the surface than in the subsurface layer of the reconstructed soil resulted from the high degree of compaction caused by the traffic of heavy machinery on the clay material. After 24 months, all experimental grass treatments showed improvements in soil aggregation compared to the bare reconstructed soil (control), mainly in the 0.00-0.05 m layer, particularly in the two Urochloa treatments (T2 and T4) and Hemarthria altissima (T5). However, the great differences between the treatments with grasses and natural soil (reference) indicate that the recovery of the pre-mining soil structure could take decades.

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