Post-mining Landscapes Research Articles

A Comparison of the Efficacy of Fuzzy Overlay and Random Forest Classification for Mapping and Shaping Perceptions of the Post-Mining Landscape of Gauteng, South Africa

Post-mining landscapes are multifaceted, comprising multiple characteristics, more so in big metropolitan regions such as Gauteng, South Africa. This paper evaluates the efficacy of Fuzzy overlay and Random Forest classification for integrating and representing post-mining landscapes and how this influences the perception of these landscapes. To this end, this paper uses GISs, MCDA, Fuzzy overlay, and Random Forest classification models to integrate post-mining landscape characteristics derived from the literature. It assesses the results using an accuracy assessment, area statistics, and correlation analysis. The findings from this study indicate that both Fuzzy overlay and Random Forest classification are applicable for integrating multiple landscape characteristics at varying degrees. The resultant maps show some similarity in highlighting mine waste cutting across the province. However, the Fuzzy overlay map has higher accuracy and extends over a larger footprint owing to the model’s use of a range of 0 to 1. This shows both areas of low and high memberships, as well as partial membership as intermediate values. This model also demonstrates strong relationships with regions characterised by landscape transformation and waste and weak relationships with areas of economic decline and inaccessibility. In contrast, the Random Forrest classification model, though also useful for classification purposes, presents a lower accuracy score and smaller footprint. Moreover, it uses discrete values and does not highlight some areas of interaction between landscape characteristics. The Fuzzy overlay model was found to be more favourable for integrating post-mining landscape characteristics in this study as it captures the nuances in the composition of this landscape. These findings highlight the importance of mapping methods such as Fuzzy overlay for an integrated representation and shaping the perception and understanding of the locality and extent of complex landscapes such as post-mining landscapes. Methods such as Fuzzy overlay can support research, planning, and decision-making by providing a nuanced representation of how multiple landscape characteristics are integrated and interact in space and how this influences public perception and policy outcomes.

Landscape in Transition, Heritage in the Making: A Research Agenda for Understanding Lusatia’s Post-mining Landscape as a Practice of Past Presencing

The region of Lusatia in Germany is characterised by a permanent state of uncertainty – as a consequence of decades of resettlements due to lignite mining as well as structural changes resulting from the German reunification. This article discusses an inclusive concept of post-mining landscapes and the presencing of their pasts in regional discourses, given that lignite mining in Lusatia mainly took place in the settlement area of the autochthonous minority of the Sorbs/Wends. Since the end of lignite mining is planned for 2038, historicizing perspectives such as a World Heritage initiative are becoming increasingly important, leading to a new conceptualisation of the post-mining landscape primarily as a practice of past presencing itself, which functions as a coping mechanism for facing up to new uncertainties, thereby emerging as a new action arena for the negotiation of regional identity, belonging and power structures.

What’s in a landscape? Nature, memory, and tourism in Bitterfeld-Wolfen’s post-mining landscape, East Germany

This paper addresses the transformation of the region around the twin-town Bitterfeld-Wolfen in Eastern Germany from a highly polluted industrial hub into a lakeland idyll and destination for recreation and nature-based tourism. From the perspective of local residents of age, the significance of this transformation was fundamentally shaped by German reunification, in particular by the experience of stigmatisation related to high levels of pollution in Bitterfeld-Wolfen in the context of general bias that devalued East German subjectivities in the course of German reunification. As I detail through both historical and ethnographic research, I show how mine restoration and the clean-up of contaminated sites have subsequently acquired meaning beyond ecological recovery and the improvement of public health. Tied up with the uncertainties and ambivalences of the transformation of East Germany and its integration into a West German entity, I demonstrate how the (im)possibility of restoring a destroyed landscape became inseparable from the postulated need of fundamental recovery of an East German region and its inhabitants from, so-perceived, socialist ruination. Consequently, I argue, the clean-up of contaminated sites and the remediation of a large open-cast mine in (former) East Germany produced not only an idyllic post-mining landscape, but a post-socialist one. Furthermore, as an archive of local history, the restored landscape became a way for elderly people to re-appropriate their past through its transformation into a remarkable present. In tracing this contested history, this paper contributes to landscape-centred analyses of post-socialist transformations in Europe.

Assessing Land Suitability for Lamtoro (Leucaena leucocephala) in Reclaimed Mining Lands of Sanggau Regency, West Kalimantan

This study evaluates the suitability of reclaimed zircon mining land in Sanggau Regency, West Kalimantan for cultivating Lamtoro (Leucaena leucocephala), a versatile plant used for forage and as a biomass energy source. Utilizing the weight factor matching method, we analyzed a range of land characteristics including soil texture, drainage, pH, and organic carbon content, as well as environmental factors such as temperature and rainfall. Initial assessments categorized the land as marginally suitable due to suboptimal drainage and soil texture. However, our research suggests that through strategic interventions—specifically improving soil texture using topsoil and enhancing drainage systems—the suitability of the land can be significantly upgraded. Detailed analysis shows that with these modifications, the land shifts from a marginal to a highly suitable rating for Lamtoro cultivation. The successful adaptation of Lamtoro in these reclaimed areas not only supports agricultural viability but also aids in the ecological restoration of post-mining landscapes, contributing to the achievement of sustainable development goals. This study underscores the potential of targeted land management strategies in transforming degraded mining areas into productive agricultural lands, providing a blueprint for similar reclamation efforts globally.

Quantifying mine waste rock physical weathering rate and processes for improved geomorphic post-mining landforms

Erodibility of landform surfaces depends on several factors and numerical methods are needed to predict erosion and landform evolution particularly for post-mining landscapes. Surface armouring caused by immobile coarse particles tends to reduce the erosion potential of landform surfaces significantly. However, the breakdown of such material through weathering could destabilise this armour and lead to high erosion rates. Hence, the surface erodibility of newly constructed landforms (here we focus on post-mining landforms) can rapidly change over a few years to decades. At present, it is difficult to predict with certainty the rate, or in some cases the dominant processes and pathways, of soil erodibility and soil production over post-mining landscape design lifetimes (typically 100–1000 years). To improve our understandings of soil evolution and its relationship to soil erosion, data is needed to determine the rate at which fine transportable material is produced from the weathering of larger, non-transportable particles, the resultant fragment size distribution together, and how that distribution evolves over time.Here, laboratory weathering experiments were conducted for four different materials from a single coal mine in the Bowen Basin, Queensland, Australia. Wetting and drying cycles were found to rapidly weather all materials. After 32 wet and dry cycles, all materials had a less coarse particle size distribution than at the start. Heating and cooling had no measurable influence on weathering. Due to the rapid reduction of particle sizes caused by high weathering rates, the materials examined would not provide surface armour capability. A new mathematical methodology was developed to determine the weathering parameters for an existing numerical model based on the weathering mechanism and particle size-dependent weathering rate. Although the materials were collected from the same geographical location, they undergo weathering through different mechanisms and rates. Size dependent weathering rate analysis showed that most samples have high weathering rates for large particles and lower weathering rates for smaller particles. The methods used here are simple and inexpensive and can be easily employed to assess mine rehabilitation materials' weathering and armour potential.

Spatial estimation of soil organic carbon, total nitrogen, and soil water storage in reclaimed post-mining site based on remote sensing data

The estimation of Soil Organic Carbon (SOC), Total Nitrogen (TN), and Soil Water Storage (SWS) is crucial in comprehending ecosystem services and environmental sustainability. It plays a crucial role in guiding sustainable restoration strategies and supporting the long-term health of post-mining sites. Remote sensing technology provides valuable tools for modelling and mapping soil properties in reclaimed post-mining sites efficiently and cost-effectively. This study aimed to utilize remote sensing data to estimate SOC, TN, and SWS in a reclaimed post-mining site. Field data was collected from 130 research plots to obtain reference data for SOC, TN, and SWS from the Sonica hard coal post-mine spoil heap. Remote sensing data were: airborne laser scanning (ALS) point clouds and Planets cope satellite imageries. Generalized Additive Models (GAM) were used to develop predictive models. Wall-to-wall predictions of analyzed variables were performed. The results identified topographic and remote sensing indicators that significantly influence SOC, TN, and SWS. Digital Terrain Model (DTM), aspect, and blue spectral band are variables that explain SOC storage, with a significant influence of DTM, ranging from −8 to 18 Mg ha−1. TN was explained by DTM, Canopy Height Model (CHM), blue and Near Infrared (NIR) spectral bands, and Normalized Difference Vegetation Index (NDVI), mainly influenced by NIR and NDVI, ranging from −1.1 to 0.8 and −0.9 to 1.4 Mg ha−1, respectively. The values of Topographic Wetness Index (TWI), aspect, CHM, blue and NIR spectral bands explained SWS, highlighting their importance in assessing soil water dynamics in post-mining landscapes, with TWI and CHM being particularly influential, ranging from −2 to 5.1 and −6 to 2 mm, respectively. However, caution is advised when predicting SOC and TN using remote sensing in post-mining sites due to geogenic carbon considerations.

Biological potential of eight medicinal plants collected in the restored landscape after mining in South Kalimantan

Land restoration is expected to enhance the supply of valuable ecosystem resources such as herbaceous bushes and weeds. This study aimed to determine the primary phytochemical constituents and bioactivities of methanol extracts from eight bushes and weeds collected from a restored post-mining landscape in South Kalimantan, Indonesia. Qualitative phytochemical analysis showed the presence of phenolic compounds, flavonoids, tannins, alkaloids, steroids, terpenoids and saponins in the methanol extracts of herbaceous plants. Their antioxidant activity was measured by using the 2,2-diphenyl-1-picryl-hydrazyl-hydrate assay. Their superoxide dismutase (SOD) activity was also measured. In addition, selected plant extracts were screened against the common human pathogens Staphylococcus aureus and Candida albicans. Phytochemical analysis showed that the methanol extracts contained all the bioactive compounds examined in this study except the one from Lycopodium cernuum, which lacked flavonoids and alkaloids. Further investigation revealed that all methanol extracts except the one from L. cernuum had promising antioxidant potential. The methanol extracts from Chromolaena odorata (stem), Trema micrantha, Melastoma malabathricum (flower and leaf) and Thypa angustifolia exhibited effective antibacterial activity. In addition, the methanol extracts from M. malabathricum (flower and leaf), T. micrantha, Scleria sumatrensis and Breynia cernua (leaf) exhibited effective antifungal activity. M. malabathricum (flower and leaf) has the greatest potential as a herbaceous plant since its methanol extract exhibits the most potent antioxidant, antibacterial and antifungal activities.

Post-mining ecosystem reconstruction

The global decade of restoration brings into sharp focus the need to rehabilitate lands damaged by mining, to provide safe, stable, and productive landscapes. For the majority of mines, the required final land use is some form of natural, semi-natural or managed ecosystem, such as agriculture, aquaculture or forestry. Mining activities lead to new highly altered landscapes that require rehabilitation. These comprise various on-land stores of waste material and mined land itself. The repair of damaged ecosystems is described by many terms including restoration, rehabilitation, revegetation, ecological restoration, and reclamation. These terms overlap in meaning, have regional biases, and all fall short of what is really required: ecosystem reconstruction. This requires a highly multidisciplinary approach drawing on many disciplines including geotechnical engineering, social science, soil science, law, hydrology, botany, geology, pollination biology, financial planning, alongside ecology. Ideally, mine rehabilitation should be progressive, start early in the life of the mine, and employ a strict regime of characterising and tracking waste materials for use in creating safe and stable post-mining landscapes. These actions will limit risks and optimise outcomes, especially when waste materials contain toxic metals or have high levels of acidity, alkalinity or salinity. Some mine sites are appropriate for the restoration of native ecosystems and biodiversity that existed pre-mining, but many, including landscape features created from waste materials, are not. Criteria for successful land rehabilitation are complex, multivariate, and highly contingent on the agreed final land use. Future advances in mine rehabilitation include the use of geomorphic landscape design and emerging thinking on cradle-to-cradle mining. This primer will discuss the complex factors that need to be considered in ecosystem reconstruction after mining and outlines approaches for optimising land rehabilitation outcomes.

Facilitating early boreal forest succession on waste rock using Ramial Chipped Wood mulch: A five-year study

After a mine is closed, waste rock storage areas must be revegetated to facilitate the return of ecosystem services and meet legal and social expectations. The restoration of forest ecosystems on waste rock through spontaneous colonization associated with primary succession can take decades and is still poorly studied. Adding a mulch of ramial chipped wood (RCW) could improve the physicochemical properties and microclimate conditions of waste rock, thus facilitating substrate colonization by plants. In 2016, a fully randomized block design was installed on waste rock from a closed gold mine located in the boreal forest in Abitibi-Témiscamingue, Quebec, Canada. The design included four treatments: scarified waste rock as the control (WR), 2 cm of RCW mulch on top of scarified waste rock (RCW/WR), and 10 cm layer of sand on top of scarified waste rock with or without 2 cm of RCW mulch (RCW/S and S, respectively). Over a period of five years, we followed the natural colonization of forest species as well as abiotic (substrate microclimate conditions and physicochemistry) and biotic (herbaceous plant colonization) factors influencing woody plant colonization success. Six boreal woody species spontaneously colonized the area (five individuals per m2, on average, all species combined). Salix sp. and Picea glauca seedlings were more abundant on substrates with RCW mulch (especially sand) than those without mulch, and P. glauca had greater aerial biomasses with RCW mulch. Substrate water content during the growing season and the presence of the weed species Tussilago farfara were determining environmental factors in substrate colonization by Abies balsamea. In the absence of Tussilago farfara, RCW mulch increased A. balsamea colonization. RCW mulch increased the total cover of colonizing herbaceous plants (23.3–58.2%) as compared to mineral substrates alone (4.78–52.3%), which negatively affected the number of A. balsamea individuals. The colonizing herbaceous species were mostly primary succession species, Pilosella caespitosa, Anaphalis margaritacea, and Tussilago farfara being dominant; no exotic species were observed. The results highlight the potential of RCW mulch in promoting forest recolonization on waste rock, including mid-successional species like Picea sp., which could be useful for facilitating ecosystem succession in post-mining landscapes.

Basidiomycetes to the rescue: Mycoremediation of metal-organics co-contaminated soils.

The increasing need for metals leads to contaminated post-mining landscapes. At the same time, the contamination with organic, recalcitrant contamination increases. This poses a problem of reuse of large areas, often co-contaminated with both, metals, and organic pollutants. For the remediation of areas contaminated with multiple contaminants and combining many stress factors, technical solutions including groundwater treatment, where necessary, have been devised. However, this is applied to highly contaminated, small sites. The reuse of larger, co-contaminated landscapes remains a major challenge. Mycoremediation with fungi offers a good option for such areas. Fungi cope particularly well with heterogeneous conditions due to their adaptability and their large hyphal network. This chapter summarizes the advantages of basidiomycetes with a focus on wood rot fungi in terms of their ability to tolerate metals, radionuclides, and organic contaminants such as polycyclic aromatic hydrocarbons. It also shows how these fungi can reduce toxicity of contaminants to other organisms including plants to allow for restored land-use. The processes based on diverse molecular mechanisms are introduced and their use for mycoremediation is discussed.

The uncertain future of mountaintop-removal-mined landscapes 1: How mining changes erosion processes and variables

Surface mining may be humanity's most tangible impact on Earth's surface and will become more prevalent as the energy transition progresses. Prediction of post-mining landscape change can help mitigate environmental damage, but requires understanding how mining changes geomorphic processes and variables. Here we investigate surface mining's complex influence on surface processes in a case study of mountaintop removal/valley fill (MTR/VF) coal mining in the Appalachian Coalfields, USA. The future of MTR/VF landscapes is unclear because mining's effects on geomorphic processes are poorly understood. We use geospatial analysis—leveraging the existence of pre- and post-MTR/VF elevation models—and synthesis of literature to ask how MTR/VF alters topography, hydrology, and land-surface erodibility and how these changes could be incorporated into numerical models of post-MTR/VF landscape evolution.MTR/VF reduces slope and area–slope product, and rearranges drainage divides. Creation of closed depressions alters flow routing and casts doubt on the utility of models that assume steady flow. MTR/VF creates two contrasting hydrologic domains, one in which overland flow is generated efficiently due to a lack of infiltration capacity, and one in which waste rock deposits act as extensive subsurface reservoirs. This dichotomy creates localized hotspots of overland flow and erosion. Loss of forest cover probably reduces cohesion in near-surface soils for at least the timescale of vegetation recovery, while waste rock fills and minesoils also likely experience reduced erosion resistance. Our analysis suggests three necessary ingredients for numerical modeling of post-MTR/VF landscape change: 1) accurate routing and accumulation of unsteady overland flow and accompanying sediment across low-gradient, depression-rich, engineered landscapes, 2) separation of the landscape into cut, filled, and unmined regions, and 3) incorporation of vegetation recovery trajectories. Improved modeling of post-mining landscape evolution will mitigate environmental degradation from past mining and reduce the impacts of future mining that supports the energy transition.

Ecosystem Services for Planning Post-Mining Landscapes Using the DPSIR Framework

Mining in general, and particularly mining for energy resources such as coal and lignite, results in massive impacts on the surrounding landscape and ecosystems. Post-mining reclamation that takes account of the disturbed ecosystem services requires a research approach that links the mining impact to ecosystem functions and ecosystem service potentials. The method used in this paper combines the Driving Forces–Pressures–State–Impact–Response (DPSIR) framework and the ES cascade approach by complementing the limitations of each approach with the strengths of the other. The DPSIR framework is extended to a causal network to account for the multiple interconnected causal chains of coal and lignite mining impacts. The presented causal network supports the identification of ES indicators for the assessment, planning, and monitoring of post-mining reclamation in coal/lignite mining landscapes. The presented approach can also inform political and administrative decisions by identifying the ecosystem elements at risk of being degraded from mining.

Perspectives of lignite post-mining landscapes under changing environmental conditions: what can we learn from a comparison between the Rhenish and Lusatian region in Germany?

BackgroundThe decision of the German federal government to cease lignite mining until 2038 or—if possible—already earlier until 2030, will cause manifold transition processes in the remaining lignite mining districts of Germany. The two largest districts are located in geographically opposite regions: The Rhineland in the western part and Lusatia in the east of Germany. As particularly these two mining districts will experience severe changes in their socioeconomic as well environmental conditions, the federal government has adopted comprehensive economic support measures. However, the environmental changes will also cause altered ecosystem functions and services to be provided by the future post-mining landscapes.ResultsIn this paper, the two main lignite-producing regions of Germany are compared with regard to their natural and cultural settings. The economic situation and its history are reflected and differences are outlined. Part of the disparities in the cultural development can be explained by very different natural conditions, especially edaphic factors and climatic situation. Because of dissimilar geological settings, different mining technologies were developed and are in use in the two regions with distinct effects on the resulting post-mining landscapes.ConclusionThe long-standing and manifold lignite mining activities have radically restructured the landscapes in Lusatia and the Rhineland. With the ongoing decline of the mining industry and its complete cessation, presumably within the next decade, both regions will alter their faces significantly. These changes offer both challenges but also opportunities with respect to the post-mining landscapes and their ecosystem services they are going to provide. The prerequisites for a positive socioeconomic development and for sustainable land-use concepts that also consider ecological aspects are different for both regions. However, or especially because of these differences, the knowledge exchange and experience transfer between both mining regions are pivotal for the success of this extensive transformation process.

Restoration on magnetite mine waste substrates using Western Australian native plants only marginally benefited from a commercial inoculant

Post-mining landscapes often lack self-sustaining plant communities and functional belowground microbial communities. Inappropriate management of soil can hinder ecological restoration of mine sites. However, the potential role of microbial inoculants and plant nutrient-acquisition strategies in improving mined substrates and facilitating mine-site restoration remains relatively unexplored. An eight-month glasshouse experiment was conducted to test: (1) whether a commercially-available microbial inoculant was effective in restoring biological properties of mined substrates, and (2) the effect of plant nutrient-acquisition strategies on improving the chemical properties of mined substrates for the growth of native plants. There was no significant improvement in plant growth by adding a commercially-sourced microbial inoculant. Soil microbial biomass carbon and phosphorus increased significantly after plant growth (main effect of species * substrates * inoculation interaction). The non-mycorrhizal disturbance-specialist plant species Maireana georgei was effective in improving hostile conditions of the mine waste. Our results highlight that re-vegetating stockpiled topsoil using local keystone species is a desirable practice that can improve soil biological properties and benefit mine-site restoration. Commercially-available agricultural-based microbial inoculants may not be compatible for mine-site restoration using native plants, but future research using indigenous soil microbes is warranted.

Transformation processes in lignite post-mining landscape - erosion of anthropogenic formations in the former “Przyjazn Narodow – Szyb Babina” mine (Poland)

Transformation processes in lignite post-mining landscape - erosion of anthropogenic formations in the former “Przyjazn Narodow – Szyb Babina” mine (Poland)

MINErosion 4: Using measurements from a tilting flume-rainfall simulator facility to predict erosion rates from post-mining catchments/landscapes in Central Queensland, Australia

The use of draglines to remove overburden in Queensland opencut mines, results in landscapes that consist of long parallel tertiary overburden spoil-piles that are generally highly saline, dispersive, and highly erodible. The height of these spoil-piles may exceed 50–60 m above the original landscapes and the slopes are at the angle of repose of around 75% or 37°. Legislation and public opinion require that these highly disturbed open-cut post-mining landscapes should be satisfactorily rehabilitated into an approved post-mining land use with acceptable erosion rates. Therefore, these slopes must be reduced before the landscape can be rehabilitated. The most expensive component of the rehabilitation process is the re-shaping and preparation of the overburden to create a suitable landscape for vegetation growth. As soils and overburden varies greatly in their erodibilities, the extent and cost of earthworks can be minimized, and rehabilitation failures avoided, if soil erosion from designed landscapes can be predicted using laboratory-based parameters prior to construction of these landscapes. This paper describes the development of a model for that purpose.A catchment or landscape erosion model MINErosion 4 was developed by upscaling the existing hillslope model MINErosion 3 (So, et al., 2018) and integrate it with both ESRI ArcGIS 10.3 or QGIS 3.16 (freeware), to predict event based and mean annual erosion rate from a postmining catchment or landscape. MINErosion 3 is a model that can be used to predict event and annual erosion rates from field scale hillslopes using laboratory measured erodibility parameters or routinely measured soil physical and chemical properties, and to derive suitable landscape design parameters (slope gradient, slope length and vegetation cover) that will result in acceptable erosion rates. But it cannot be used to predict the sediment delivery from catchments or landscapes. MINErosion 4 was validated against data collected on three instrumented catchments (up to 0.91 ha in size) on the Curragh mine site in Central Queensland. The agreement between predicted (Y) and measured (X) values were very good with the regression equation of Y = 0.92X and an R2 value of 0.81 for individual storm events, and Y = 1.47X and an R2 value of 0.73 for the average annual soil loss. This is probably the first time that a catchment scale erosion is successfully predicted from laboratory measured erodibility parameters.

Modeling Water Quality of AMD along the Flow Path

The water balance is severely disturbed in post-mining landscapes like Lusatia/Germany. Mine waters (amd) enter the environment and spread in groundwater and surface waters. Groundwater containing high amounts of pyrite weathering products flows into receiving waters due to lignite mining for several years. The Chair of Wassertechnik & Siedlungswasserbau at the Brandenburg University of Technology Cottbus-Senftenberg/Germany has developed a subsurface rehabilitation method using microbial sulfate reduction over the past 25 years. A continuation of the research is unlikely. This paper has presented some research results on the behavior of groundwater acidified by mining. The acidity in the surface and groundwater is specified via the negative neutralization potential. The dominant reactions in AMD genesis and migration through the aquifer are evaluated about their acidity formation or their buffering behavior. The behavior of AMD can be summarized in a simplified way in the acidity-sulfate diagram. A flow section model (PhreeqC2) was developed and parameterized based on this. This can describe the migration of quality changes in the groundwater/aquifer system. The aquifer passage is reduced to a filtration process, analogous to water treatment. The processes occurring at compartment transitions (dump-lake-aquifer-...) can be modeled from anoxic to oxic. A first case study produces the infiltration of neutralized opencast mining lake water into an aquifer influenced by mining. Measured absorption effects during a microbiological sulfate reduction are interpreted in the second case study with an extended flow path model. The results presented are recommended for use. A comprehensive summary of the results obtained over 25 years of research is being prepared.

Modelling of Acid Mine Drainage in Open Pit Lakes Using Sentinel-2 Time-Series: A Case Study from Lusatia, Germany

Strong acid mine drainage (AMD) processes in the flooded, formerly open pits in the Lusatia area present an enormous environmental challenge for the rehabilitation of the post-mining landscape. Extensive and costly monitoring is required for optimal AMD management and remediation planning and control. Because of the large size of the area and the dimension of the problem, the regular sampling can only provide limited point data, which needs to be extrapolated to the entire area. Consequently, the search for effective approaches for extrapolating the point data to the area of all water bodies is essential for rehabilitation success monitoring and for understanding the dependencies between AMD and environmental factors such as land use, weather conditions, geology, and hydrogeology. The main aim of this study was to investigate the suitability of Sentinel-2 multispectral imagery and artificial neural networks (ANNs) for the quantitative mapping of acid mine drainage (AMD) constituents, such as dissolved iron, pH value, and sulfate in large water bodies, for an area of approximately 7220 km2 (the area of the pit lakes is about 185 km2). Correlations between different chemical water parameters were also investigated. An extensive water monitoring dataset was used to train artificial neural networks for the identification of dependencies between the multispectral remote sensing data and the water quality ground measurements. Respective relationships have been identified, especially for dissolved iron and pH. These trained ANNs have been used to produce water quality maps with high spatial (10 × 10 m) and temporal (any cloud-free period) resolution, which show the wide variability of water quality in the different parts of the mining region. Concrete sources of AMD can be identified using the water quality maps of single lakes, and the success of sanitation measures such as liming was visualized. The approach opens many doors for the optimization of both the monitoring program and sanitation technology.

Acquiring Iron-Reducing Enrichment Cultures: Environments, Methods and Quality Assessments

Lateritic duricrusts cover iron ore deposits and form spatially restricted, unique canga ecosystems endangered by mining. Iron cycling, i.e., the dissolution and subsequent precipitation of iron, is able to restitute canga duricrusts, generating new habitats for endangered biota in post-mining landscapes. As iron-reducing bacteria can accelerate this iron cycling, we aim to retrieve microbial enrichment cultures suitable to mediate the large-scale restoration of cangas. For that, we collected water and sediment samples from the Carajás National Forest and cultivated the iron-reducing microorganisms therein using a specific medium. We measured the potential to reduce iron using ferrozine assays, growth rate and metabolic activity. Six out of seven enrichment cultures effectively reduced iron, showing that different environments harbor iron-reducing bacteria. The most promising enrichment cultures were obtained from environments with repeated flooding and drying cycles, i.e., periodically inundated grasslands and a plateau of an iron mining waste pile characterized by frequent soaking. Selected enrichment cultures contained iron-reducing and fermenting bacteria, such as Serratia and Enterobacter. We found higher iron-reducing potential in enrichment cultures with a higher cell density and microorganism diversity. The obtained enrichment cultures should be tested for canga restoration to generate benefits for biodiversity and contribute to more sustainable iron mining in the region.

Standardized Method for the Parameterization of Sandy Soils for the Hypoplastic Constitutive Model - a Contribution to the Recultivation of Post-Mining Landscapes in the Lusatian Lignite Mining Region

Numerical simulations make a fundamental contribution to the optimization of geotechnical compaction methods used to stabilize soils. In such simulations it is possible to describe the complex material behavior of sands with the hypoplastic constitutive model. Despite the enormous influence of the material parameters on the calculation results, the parameterization of sands for the hypoplastic model has not been uniformly regulated so far. In this paper, different parameterization approaches are tested on a sand and their simulation results are compared. Subsequently, a proposal for the standardization of the parameterization of sands for the hypoplastic constitutive model is derived.