The environmental, social, and economic problems associated with acid mine drainage (AMD) from ab... more The environmental, social, and economic problems associated with acid mine drainage (AMD) from abandoned mine sites are globally significant. As a consequence of mining exploration of metallic mineral deposits, large quantities of sulfides are exposed to weathering processes (oxygen, water, and bacteria) that generate acidic environments and promote metal(loid) solubilization, forming so-called AMD. The pollution caused by AMD can be minimized by adopting suitable strategies and approaches to mitigate AMD or prevent its generation and migration. The current work was undertaken for an in-depth account of the generalized features of AMD and in-depth case studies of the impact of AMD in the northern part of Portugal. The first part was prepared to highlight basic features dealing with (the) origin of AMD; (2) the characteristics of AMD; (3) factors controlling the formation of AMD; (4) the environmental impact of AMD; (5) resource recovery from AMD; and (6) prevention, mitigation, and treatment of AMD. The second part accentuates in-depth case studies of mine drainage water collected bimonthly from abandoned mines situated in northern Portugal over 1 year. In the mines that were studied are acidic waters with low pH and significant concentrations of SO4, and metal(loid)s (As, Fe, Mn, Zn, Cu, Pb, Cd, and Ni), whereas in superficial natural stream waters outside the mines, the pH is close to neutral, with low conductivity and lower metal concentrations. Stream waters inside the mines have an intermediate composition between AMD and natural stream waters outside the mines. The environmental impact of the quality of the superficial waters is marked only in the closest surroundings of the pollution source (1 to 2 km). Several coherent and integrated processes contribute to this situation, such as (1) dilution by other groundwater and surface waters that flow toward stream waters; (2) precipitation or co-precipitation of metallic cations by hydroxides and sulfates; and (3) adsorption of metallic cations by organic and inorganic sediments and aquatic plants. Hydrochemical processes and the environmental impact in the study sites are important issues necessitating potential resource recovery from AMD (eg, iron or other metals) and appropriate strategies and approaches to mitigate AMD and pollution prevention.
Abstract The abandoned mine land reclamation process should encompass a design and implementation... more Abstract The abandoned mine land reclamation process should encompass a design and implementation program that addresses multidisciplinary methods and techniques. Different reclamation strategies for degraded mine areas can be delineated, which commonly include the following sequential phases: (1) preliminary environmental assessment, which allows the characterization of the current state of the site and the nature of the environmental risk; (2) the planned end state of the site; (3) detailed environmental assessment to characterize the nature and extent of negative impacts; (4) establishment of cleanup criteria for contaminants of concern; (5) development of a recovery work plan, which includes the techniques for the control, treatment, and final disposal of contaminated tailings, waters, sediments and soils, as well as the morphological and scenic configuration of the site; and (6) final verification and monitoring of the end state. The evaluation of reclamation alternatives should address the life cycle impacts of the design, namely costs, resource requirements, ecosystem services, energy needs, etc., involved in implementing both the cleanup operations and extensive monitoring programs.
Abstract Mining results in generation of huge amount of mine waste, which severely contaminates t... more Abstract Mining results in generation of huge amount of mine waste, which severely contaminates the environment. Present chapter discusses about the utilization of mycorrhizal fungi in rehabilitation of mine degraded sites especially heavy metal and coal mine–contaminated sites. Most of the works are done on pilot scale and not implemented on field level. This study presents how lab based experiments can be implemented on a field level by using ectomycorrhiza, endomycorrhiza, and dark septate fungi. A case study of coal mine of India, which shows how mycorrhizal spores play a vital role in mine restoration, is also well documented in detail.
Abstract Timor-Leste and Oecusse in particular have very little geological data coverage due to t... more Abstract Timor-Leste and Oecusse in particular have very little geological data coverage due to the many conflicts generated mainly by Portuguese colonization and Indonesian occupation. The main work that has been done was aimed at oil prospecting on the south coast. A regional stream sediment campaign was started from the Maquelab area in the Oecusse enclave, west of Timor-Leste, where no mineralization had been reported before. The geochemical characteristics of stream sediments in Maquelab area drainage basins, located in NW of Oecusse enclave, Timor-Leste, were investigated in order to establish the geochemical baseline conditions prior to any type of new mineral occurrences. Stream sediments demonstrated a different chemical composition with elevated values mainly for Cr (49–12,520 mg kg−1), Ni (11.6–863 mg kg−1) and Co (19.8–77.1 mg kg−1) which was not expected going by the present geological cartography of the area where the existence of ultramafic rocks is not supported. Principal component analysis (PCA) was used after centered log-ratio (CLR) transformation of data that allowed for the observance of different compositional groupings and the identification of the drainage basins they represented. Aided by the stream sediments geochemical results, a geological recognition of the area was then made, which allowed for the discovery of a new ultramafic complex, consisting of dunites, peridotites and serpentinites, containing metamorphic rocks, predominantly calc-silicate, basalts and gabbros. This complex is named the Maquelab Complex due to its proximity to this village. Inside the peridotitic rocks, small boulders of massive chromite with about 56% Cr2O3 were also found.
Abstract Tree species growing on tailings and mine-contaminated soils show tolerance to imposed s... more Abstract Tree species growing on tailings and mine-contaminated soils show tolerance to imposed stress conditions (metal contamination and nutrient deficiency) and can fulfill the objectives of stabilization, pollution attenuation, and visual improvement. A few trees, of the Pinus , Eucalyptus , and Quercus species, found in tailings and contaminated soils in abandoned mines of Portugal, show accumulation of different metals in the above-ground tissues. Hence these communities tolerant to toxic trace elements play a major role in remediation of degraded mine soils. Furthermore, these plants could grow and propagate in substrata with low nutrient conditions, which would be a great advantage in the revegetation of mine tailings. It was also observed that despite lower accumulation when compared to herbaceous and shrub species, trees of the studied regions can be very effective for metals phytoextraction and phytostabilization due to their higher biomass and bioproductivity, especially when established in the less contaminated soils on the peripheral zone of the studied areas. Furthermore, when the metal concentrations in the above-ground parts were maintained at low levels, the biomass can be used to obtain economic value.
The environmental, social, and economic problems associated with acid mine drainage (AMD) from ab... more The environmental, social, and economic problems associated with acid mine drainage (AMD) from abandoned mine sites are globally significant. As a consequence of mining exploration of metallic mineral deposits, large quantities of sulfides are exposed to weathering processes (oxygen, water, and bacteria) that generate acidic environments and promote metal(loid) solubilization, forming so-called AMD. The pollution caused by AMD can be minimized by adopting suitable strategies and approaches to mitigate AMD or prevent its generation and migration. The current work was undertaken for an in-depth account of the generalized features of AMD and in-depth case studies of the impact of AMD in the northern part of Portugal. The first part was prepared to highlight basic features dealing with (the) origin of AMD; (2) the characteristics of AMD; (3) factors controlling the formation of AMD; (4) the environmental impact of AMD; (5) resource recovery from AMD; and (6) prevention, mitigation, and treatment of AMD. The second part accentuates in-depth case studies of mine drainage water collected bimonthly from abandoned mines situated in northern Portugal over 1 year. In the mines that were studied are acidic waters with low pH and significant concentrations of SO4, and metal(loid)s (As, Fe, Mn, Zn, Cu, Pb, Cd, and Ni), whereas in superficial natural stream waters outside the mines, the pH is close to neutral, with low conductivity and lower metal concentrations. Stream waters inside the mines have an intermediate composition between AMD and natural stream waters outside the mines. The environmental impact of the quality of the superficial waters is marked only in the closest surroundings of the pollution source (1 to 2 km). Several coherent and integrated processes contribute to this situation, such as (1) dilution by other groundwater and surface waters that flow toward stream waters; (2) precipitation or co-precipitation of metallic cations by hydroxides and sulfates; and (3) adsorption of metallic cations by organic and inorganic sediments and aquatic plants. Hydrochemical processes and the environmental impact in the study sites are important issues necessitating potential resource recovery from AMD (eg, iron or other metals) and appropriate strategies and approaches to mitigate AMD and pollution prevention.
Abstract The abandoned mine land reclamation process should encompass a design and implementation... more Abstract The abandoned mine land reclamation process should encompass a design and implementation program that addresses multidisciplinary methods and techniques. Different reclamation strategies for degraded mine areas can be delineated, which commonly include the following sequential phases: (1) preliminary environmental assessment, which allows the characterization of the current state of the site and the nature of the environmental risk; (2) the planned end state of the site; (3) detailed environmental assessment to characterize the nature and extent of negative impacts; (4) establishment of cleanup criteria for contaminants of concern; (5) development of a recovery work plan, which includes the techniques for the control, treatment, and final disposal of contaminated tailings, waters, sediments and soils, as well as the morphological and scenic configuration of the site; and (6) final verification and monitoring of the end state. The evaluation of reclamation alternatives should address the life cycle impacts of the design, namely costs, resource requirements, ecosystem services, energy needs, etc., involved in implementing both the cleanup operations and extensive monitoring programs.
Abstract Mining results in generation of huge amount of mine waste, which severely contaminates t... more Abstract Mining results in generation of huge amount of mine waste, which severely contaminates the environment. Present chapter discusses about the utilization of mycorrhizal fungi in rehabilitation of mine degraded sites especially heavy metal and coal mine–contaminated sites. Most of the works are done on pilot scale and not implemented on field level. This study presents how lab based experiments can be implemented on a field level by using ectomycorrhiza, endomycorrhiza, and dark septate fungi. A case study of coal mine of India, which shows how mycorrhizal spores play a vital role in mine restoration, is also well documented in detail.
Abstract Timor-Leste and Oecusse in particular have very little geological data coverage due to t... more Abstract Timor-Leste and Oecusse in particular have very little geological data coverage due to the many conflicts generated mainly by Portuguese colonization and Indonesian occupation. The main work that has been done was aimed at oil prospecting on the south coast. A regional stream sediment campaign was started from the Maquelab area in the Oecusse enclave, west of Timor-Leste, where no mineralization had been reported before. The geochemical characteristics of stream sediments in Maquelab area drainage basins, located in NW of Oecusse enclave, Timor-Leste, were investigated in order to establish the geochemical baseline conditions prior to any type of new mineral occurrences. Stream sediments demonstrated a different chemical composition with elevated values mainly for Cr (49–12,520 mg kg−1), Ni (11.6–863 mg kg−1) and Co (19.8–77.1 mg kg−1) which was not expected going by the present geological cartography of the area where the existence of ultramafic rocks is not supported. Principal component analysis (PCA) was used after centered log-ratio (CLR) transformation of data that allowed for the observance of different compositional groupings and the identification of the drainage basins they represented. Aided by the stream sediments geochemical results, a geological recognition of the area was then made, which allowed for the discovery of a new ultramafic complex, consisting of dunites, peridotites and serpentinites, containing metamorphic rocks, predominantly calc-silicate, basalts and gabbros. This complex is named the Maquelab Complex due to its proximity to this village. Inside the peridotitic rocks, small boulders of massive chromite with about 56% Cr2O3 were also found.
Abstract Tree species growing on tailings and mine-contaminated soils show tolerance to imposed s... more Abstract Tree species growing on tailings and mine-contaminated soils show tolerance to imposed stress conditions (metal contamination and nutrient deficiency) and can fulfill the objectives of stabilization, pollution attenuation, and visual improvement. A few trees, of the Pinus , Eucalyptus , and Quercus species, found in tailings and contaminated soils in abandoned mines of Portugal, show accumulation of different metals in the above-ground tissues. Hence these communities tolerant to toxic trace elements play a major role in remediation of degraded mine soils. Furthermore, these plants could grow and propagate in substrata with low nutrient conditions, which would be a great advantage in the revegetation of mine tailings. It was also observed that despite lower accumulation when compared to herbaceous and shrub species, trees of the studied regions can be very effective for metals phytoextraction and phytostabilization due to their higher biomass and bioproductivity, especially when established in the less contaminated soils on the peripheral zone of the studied areas. Furthermore, when the metal concentrations in the above-ground parts were maintained at low levels, the biomass can be used to obtain economic value.
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