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The chemical composition of mine water discharged from flooded underground mines typically improves over time. This phenomenon is called first flush and can be described by a characteristic curve. Shortly after the mine water begins to discharge, water constituent concentrations rise and then fall in an almost exponential curve, improving water quality over time. In this study, the change in mine water quality was investigated throughout the mine water body. This mine water body commonly consists of different water bodies with individual densities, resulting in mine water stratification. Anthropogenic disturbance of the mine water body can disrupt this stratification and also the positive effect of the first flush. To better understand and predict the first flush, the first flush was simulated experimentally using an analogue model of a flooded underground mine, the Agricola Model Mine. The results were compared with field studies to help understanding and predicting the change in mine water quality. Overall, the results suggest that the first flush occurs throughout the mine water body, making it similar to a chemical reactor. This better understanding of the process can lead to more effective mine water management and design of mine water treatment facilities. [ABSTRACT FROM AUTHOR]

The mineland rehabilitation can be a challenge due to high soil density and low levels of organic matter and nutrients. This study assessed soil chemical attributes and leaf nutritional contents of two native species (Mimosa acutistipula var. ferrea and Vismia baccifera) grown in an iron waste pile under environmental rehabilitation in the Carajás Mineral Province, Eastern Amazon, Brazil. Soil samples were collected close to plant species in three different chronosequences of rehabilitation. Regardless of the rehabilitation stage, the soils have low levels of phosphorus, potassium, calcium, magnesium, and boron. A tendency of organic matter accumulation was observed at the advanced stage (5–8 years after the onset of rehabilitation process) and it was correlated with other soil nutrients. The leaf nutrient' contents of M. acutistipula and V. baccifera tend to be distinct from each other, which could indicate that the studied species have different nutritional requirements. The V. baccifera presented higher leaf concentrations of sulfur, copper, and zinc, while M. acutistipula stood out for presenting a higher leaf nitrogen content, which is possibly related to its nitrogen-fixing capacity. In general, an improvement of soil chemical attributes was achieved with the advance of the rehabilitation stages, showing the efficiency of the procedures performed to rehabilitate the studied areas. [ABSTRACT FROM AUTHOR]

The theory of Professor Stanislaw Knothe, known as Knothe's Theory, has been the foundation for practical predictive calculations of the impacts of exploitation for many years. It has enabled the large-scale extraction of coal, salt and metal ores located in the protective pillars of cities and prime surface structures. Knothe's Theory has been successfully applied in Polish and global mining for over seventy years, making it one of the most well-known and recognized achievements in Polish mining science. Knothe's Theory provides a temporal-spatial description of subsidence that relies on four essential parameters: the vertical scale parameter a, the horizontal displacement parameter λ, the horizontal range scale parameter cotβ and the time scale parameter c. This article characterizes the parameters of Knothe's Theory used in various current applications for calculating subsidence, surface and rock uplift, and other applications of the theory, even beyond its classical form. The presented solutions are based on a mathematical model of the interaction of a complex element and cover topics such as subsidence during full exploitation with roof collapse and full exploitation with backfilling, pillar-room mining, the effect of salt caverns on the surface and salt rock, and fluid deposits and surface uplift caused by changes in the water level within closed coal mines. The article also discusses the evolution of the range angle of the main influences and presents Knothe's solutions related to time, describing the horizontal displacement parameter λ. [ABSTRACT FROM AUTHOR]

The problem of sustainability of energy production in the context of the expansion of renewable energy cannot be solved without a deep technological modernization of the fossil fuels extraction in line with Industry 4.0. Along with this, the expected transition to the human-centric Industry 5.0 raises the question for researchers: what core technologies of the Mining 4.0 platform will determine its transformation into Mining 5.0 in order to meet the imperative of sustainable development and the dominance of green energy. This review presents a multifaceted overview of Mining 4.0 core technologies, derived from Industry 4.0, such as smart sensors, neural networks, Big Data analytics, Internet of Things, digital twins and artificial intelligence, that form cyber-physical systems for high-performance and complete extraction of fossil energy sources. The review of works in the field of transition to Industry 5.0 is associated with Mining 5.0 core technologies—Cloud Mining, post-mining, biochemical extraction of minerals and production of green hydrogen fuel from fossil hydrocarbons, which is expected after 2050. A conclusion is made about the need for a deep analysis of harmonizing the possibilities for the innovative development of fossil fuel sources and renewable energy for sustainable energy production in the upcoming decades. [ABSTRACT FROM AUTHOR]

This article aims to make a diagnosis of the current situation of mine closure in Colombia, to transfer the knowledge and experience lived by Germany in this aspect, to identify the regulations that have been established in the country to date concerning to mine closure, the challenges faced by the country, the initiatives and possible solutions that the country has carried out at present to ensure proper closure exposing success stories and finally concludes the needs, those responsible and how to address this relevant and critical issue for the country. [ABSTRACT FROM AUTHOR]

Spatio-temporal ground-movement measurements and mappings have been carried out in the Campine coalfield in Belgian Limburg since the closure of the mines to document post-mining effects. MT-InSAR measurements are compared to groundwater head changes in the overburden and to height data from the closest GNSS stations. Radar interferometry is used to estimate the extension and the velocity of ground movements. In particular, the MT-InSAR technique has been applied to SAR acquisitions of the satellites ERS-1/2 (1991–2005), ENVISAT (2003–2010), COSMO-SkyMed (2011–2014), and Sentinel-1A (2014–2022). The images were processed and used to highlight a switch from subsidence to uplift conditions in the western part of the coal basin, while the eastern part had already been affected by a rebound since the beginning of the ERS-1/2 acquisitions. Following the closure of the last active colliery of Zolder in 1992 and the subsequent cease of mine-water pumping, a recharge of mine-water aquifers occurred in the western part of the basin. This process provoked the change from subsidence to uplift conditions that was recorded during the ENVISAT period. In the center of the coal-mining area, measured uplift velocities reached a maximum of 18 mm/year during the ENVISAT period, while they subsided at −12 mm/year during the ERS-1/2 period. Mean velocities in the western and eastern parts of the coalfield area have decreased since the last MT-InSAR measurements were performed using Sentinel-1A, while the Zolder coal mine continues to rise at a faster-than-average rate of a maximum of 16 mm/year. The eastern part of the coalfield is still uplifting, while its rate has been reduced from 18 mm/year (ERS-1/2) to 9 mm/year (Sentinel-1A) since the beginning of the radar–satellite observations. Time-series data from the two GNSS stations present in the study area were used for a local comparison with the evolution of ground movements observed by MT-InSAR. Two leveling campaigns (2000, 2013) were also used to make comparisons with the MT-InSAR data. The station's measurements and the leveling data were in line with the MT-InSAR data. Overall, major ground movements are obviously limited to an extension of the actual underground-mining works and rapidly diminish outside of them. [ABSTRACT FROM AUTHOR]

The end of hard coal mining in Germany and other European countries has been leading to new challenges in post-mining and utilisation of abandoned mines while opening up new perspectives concerning the remains of former mining as well as new fields of work for specialised personnel at the same time. Coping with the resulting perpetual tasks places new demands on already trained experts and offers the opportunity to familiarise the next generation of students with post-mining issues and solution approaches from the beginning. This article presents two closely interrelated projects – the USAMIN Project and the PepperMINT Project – which aim to successfully recruit and train future professionals. For this purpose, the USAMIN (USe of Abandoned MINes) Project creates a new form of distance learning as multilateral cooperation, which strengthens the training of specialised experts and the scientific exchange across European borders. Furthermore, the main goal of this project is the establishment of networks between scientists and other experts, thus strengthening international cooperation. The PepperMINT Project’s STEM online courses aim to motivate high school students to pursue STEM studies by introducing them to the field of engineering, while simultaneously strengthening students, especially in their first semesters. By linking the two projects, various actors can be connected according to their education and a large part of the education chain can be viewed in a holistic approach. [ABSTRACT FROM AUTHOR]

Mining of minerals impacts all components of the ecosystem and the post-mining environment should be continuously monitored to control the quality and efficiency of reclamation procedures. In the past post-mining areas often did not undergo the full process of reclamation and were left unmonitored. This study was aimed at analysis of surface (gully) erosion in an abandoned lignite post-mining area located in the present cross border German-Polish Geopark Muskau Arch. For this purpose, low-cost unmanned aerial vehicle (UAV) photogrammetry to acquire data describing the surface condition of partly rehabilitated dump sites and subsequently a digital elevation model (DEM) of difference (DoD) approach to analyse quantitatively elevation change were applied. The results based on processing of data from four UAV missions carried out between Spring 2020 and Autumn 2021 (18 months) allowed to determine the elevation models with high accuracy (±0.02 – ±0.04 m) and develop differential elevation models for the estimation of material movement and surface change in three selected gullies. All of the study sites were subjected to surface erosion probably due to the effect of rainfall that caused natural landscaping of the area. The greatest observed elevation changes connected with loss of material in research crosssections reached 0.9 m. The UAV based data calculation of the DEM of difference has proved a time efficient and accurate method for analysis of elevation change in post-mining areas subjected to surface erosion. For the best results it is recommended to plan the UAV flight missions when the sun is at its highest or in cloudy weather to minimise the effect of sunshading on the quality of the generated DEMs. A further study to correlate material movement with precipitation records is planned. [ABSTRACT FROM AUTHOR]

The Ruhr Basin in Germany is one of the most extensively studied 3D rock volumes due to subsurface coal mining over the past centuries. With the final closure of the last coalfield in 2018, mine flooding was initiated and may result in induced ground movements. However, abandoned coal mines also provide the possibility for post-mining geothermal utilisation. To improve the understanding of rock properties with respect to flow properties and heat flux in the Ruhr Basin, three drill cores of clastic sedimentary rocks of the Westphalian A (Langsettian) and Westphalian B (Duckmantian) were characterised and the facies analysed. The studied 270 m core material show 4th order sequences of coarsening- and fining-upward cycles in an overall shallowing upward trend. Up to 17 m thick sandstone beds are associated with the delta front, mudstones and siltstones are related to the lower delta plain and up to 4 m thick coal seams linked to wetlands of the lower delta plain. Rock properties show low compressional velocities with a minimum of 2,886 m/s in sandstones of the delta front, which are negatively correlated with porosities of up to 15.6%. Likewise, porosity is a major control on thermal conductivity with a minimum of 2.3 W/(m×K) for high porosity sandstones. For less porous samples, thermal conductivity becomes less dependent on porosity but more strongly on mineralogy. Comparing our results with accessible thermal conductivity data from North Rhine-Westphalia (NRW), the high values of up to 5.3 W/(m×K) seem promising for potential geothermal applications. Furthermore, the results of this study imply that the classification based on facies associations is less suitable than the classification based on grain sizes in order to assess the geothermal potential. Overall, the Upper Carboniferous (Pennsylvanian) samples of this study show low porosity (mean 5.6%) and permeability (mean 0.1 mD). Thus fluid flow during mine flooding and potential future geothermal applications will primarily rely on permeable faults and fracture systems around the abandoned mine galleries as well as the galleries themselves. [ABSTRACT FROM AUTHOR]

As part of the FloodRisk project, the influence of rising mine water in abandoned coal mines on induced seismicity is investigated. The Seismological Observatory of the Ruhr University Bochum operates a monitoring network for the whole Ruhr area (North Rhine-Westphalia, Germany) since 1983. The local scale FloodRisk network was installed in the eastern part of the Ruhr area in 2020. The continuous monitoring opens up the opportunity for a long-term study of seismicity in combination with water levels related to mining in the region. The resulting database for the eastern Ruhr area includes over 13,000 induced earthquakes in a period of 26 years during active mining, very few events in the postmining phase before the onset of flooding and more than 1,700 events in the first two and a half years of flooding. The seismological database is supplemented by the mine water levels, which are regularly measured at various measuring points distributed over the study dewatering area “Haus Aden” and made available by Ruhrkohle Aktiengesellschaft (RAG). Seismic activity was highest in the phase of active mining and concentrated in the vicinity of the mining areas. After the end of mining, only very low seismicity was detected. With the start of flooding, significantly more events were registered again. The rise curve of the mine water level and the temporal and spatial distribution of the seismicity are observed and analysed. Five temporal flooding phases are identified in which the correlated seismicity shows different distribution patterns. Phases in which the levels of individual sections of the mine merge in flooding show particularly high seismicity. A strong spatial clustering of well-localised events occurs below the deepest flooded levels of the mine. Several mechanisms that alter the stress in active mining and flooded mines and induce seismic events are known from previous studies. To apply this to our study, particular attention is given to the spatial distribution of seismicity in relation to known geologic and mining structures. In the flooding phase, most of the seismicity is localised in the area below the flooded drifts. [ABSTRACT FROM AUTHOR]

For the Research Centre of Post-Mining (FZN) at the Technische Hochschule Georg Agricola University (THGA) in Bochum, geomonitoring is a multi-level approach to environmental monitoring with a focus on post-mining activities. In situ, a precise understanding of natural processes, e.g. the condition of groundwater, water bodies, soil or vegetation, is developed – usually through mapping, laboratory analyses and installed sensors. The goal is to later be able to derive an areawide statement on these processes through the analysis of satellite data. In order to be able to transfer the process understanding gained to the satellite data, an unmanned aerial vehicle is used. This article highlights an essential aspect of the in situ component. The denser the coverage with sensors, the more reliably an area-wide statement about drones and satellites can succeed. This is why low-cost temperature and soil moisture sensors and loggers are also used in the FZN research projects. In the “Climate Change – Management and Monitoring (C2M2)” project, funded by the Emschergenossenschaft-Lippeverband (EGLV), such sensors could be evaluated in several tests. The article presents initial results aimed at mapping an annual cycle of soil moisture with such inexpensive sensors. As a result, no physically correct measurements can be achieved with these sensors, but they are able to show patterns in processes and, for example, map such annual cycles. With the appropriate interpretation, they can thus deliver a contribution to understand processes. [ABSTRACT FROM AUTHOR]

Fractures in subsurface lithologies globally host economically significant energy resources and can be preferential fluid migration pathways. With the naturally fractured Upper Carboniferous sandstones of the Ruhr Basin located within Germany’s most densely populated area, the utilisation for powering one of Europe’s largest district heating infrastructure can be an option. Since the Upper Carboniferous sandstone matrix exhibits poor reservoir quality (average porosity: 8%, permeability: up to 3 mD), fractures are believed to primarily control fluid flow. By combining data from two outcrops (exposing the Namurian C and Westphalian A) with a wellbore data set (penetrating the Westphalian A), this study aims to develop a refined understanding of the fracture network. The present-day stress control on hydraulically conductive fracture orientations is studied by performing critically stressed fracture analysis for three different SHmax orientation scenarios. Kaisberg (Namurian C) and Finefrau (Westphalian A) Sandstone outcrops show three dominant fracture trends: NNW– SSE to N–S, NNE–SSW to NE–SW and WNW–ESE. The characterised fracture networks of both outcrops follow a top-bounded height distribution pattern, with fractures being mostly bed restricted. Therefore, bed thickness is identified as a controlling factor limiting fracture height. Based on 600 m of oriented core material from the Upper Carboniferous strata (Bork 10 wellbore), the analysis of the in-situ fracture network revealed two dominant fracture orientations: N–S and W–E. Fracture intensity indicates a varying degree of fracturing of the drilled sandstone layers for both trends (N–S: 0 to 9.1 m-1, W–E: 0 to 8.8 m-1). Comparison of dipmeter log fracture interpretations with reliable core description data shows a poor match (11%) for depth location (± 6 m) and dip azimuth (± 25°). Slip tendency analysis highlighted near-vertical N–S and NW–SE striking fractures to be generally favourably oriented for reactivation within the active stress field. In total, 10% of the detected fracture population (Bork 10 wellbore) are critically stressed under present-day stress conditions and may contribute to large scale fluid flow in the subsurface. [ABSTRACT FROM AUTHOR]

Mining of hard coal creates large underground cavities, which significantly affect the subsurface and land surface. Observations of land surface behaviour after the closure of mines demonstrate that these threats do not disappear. During mine water rebound in the post-mining phase of underground coalmines, the water flows into the open mine workings and other altered or fissured areas. This paper provides early observations from the PostMinQuake project, which is designed to identify mechanisms, relevant parameters and dependencies of mining and geological parameters causing post-mining seismicity in several European coal regions. It also presents the correlation between seismicity and water table level in the studied basins that has been observed during the post-mining phase and shows the necessity of implementing new procedures to monitor these seismic events. [ABSTRACT FROM AUTHOR]

The successive end of hard coal mining, which took place in the various coalfields in Germany by 2018, poses the risk of possible future mining damage related to mine water rise after mine closure. In this study, an interdisciplinary approach of structural geological and geochemical methods was applied to detect active fault zones, as a first step for long-term monitoring of mine flooding. The geomechanical analysis in the area of the soil gas campaign at the former coal mine “Haus Aden” shows high dilation and moderate slip tendencies as well as the potential for critical stress of the selected fault section of the Königsborn Fault. These features indicate the section under consideration as a preferred gas migration pathway. Soil gas measurements showed correspondingly clear anomalies of the components CO2, 222Rn and O2, which together with the results of the geomechanical analysis are a strong indicator for a structurally controlled migration of the gases and thus evidence of the modelled fault outcrop. A possible accompanying fault could not be identified properly, mainly because of the ambiguous CO2 concentrations. A positive correlation of CO2 and 222Rn can be a supplementary statistical tool to better assign unclear gas anomalies. However, this approach is limited by the radioactive decay of 222Rn and individual site parameters (groundwater, gas permeabilities). The primary mine gas CH4 could not be detected, which is probably related to its oxidative decomposition with formation of CO2. In the next step, it is planned to validate the current results with area-wide measurements if possible and then to expand selected boreholes to gas gauges. Newly developed, permanent gas sensors will be installed into these gas gauges for long-term monitoring of mine flooding. The aim is to provide new low-cost options for flooding monitoring in order to be able to estimate induced seismicity and mine damage. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine the effects of biochar and manure additions to growth performance, nutrient value, in vitro digestibility, and rumen fermentation characteristics of Pennisetum purpureum cv. Mott grown in soil remaining after nickel-mining activities. The goat manure and iron wood biochar were used in this study. Treatments were arranged 4 x 2 factorially in a completely randomized block design. The factors were four levels of biochar (0, 5, 10, and 15 metric ton/ha) and two levels of manure (0 and 10 metric ton/ha). The plants were harvested at 70 days after sowing (first harvest), 128 days (first ratoon) and 193 days (second ratoon). Results showed that at first and second ratoon, plant height and tillering number were increased after 5 metric ton/ha biochar and 10 metric ton/ha manure additions (p < 0.05). Manure treatment resulted in higher crude protein content (p < 0.05) than controls at first and second ratoon stages. Combinations of biochar (p < 0.01) and manure (p = 0.09) improved in vitro gas production from the insoluble fraction (b). The study concludes that treatment with 5 metric ton/ha biochar and 10 metric ton/ha manure fertilizers on post-nickel-mining soil increases tillering number, height, CP content and in vitro digestibility of P. purpureum cv. Mott at ratoon stages. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine the effects of biochar and manure additions to growth performance, nutrient value, in vitro digestibility, and rumen fermentation characteristics of Pennisetum purpureum cv. Mott grown in soil remaining after nickel-mining activities. The goat manure and iron wood biochar were used in this study. Treatments were arranged 4 x 2 factorially in a completely randomized block design. The factors were four levels of biochar (0, 5, 10, and 15 metric ton/ha) and two levels of manure (0 and 10 metric ton/ha). The plants were harvested at 70 days after sowing (first harvest), 128 days (first ratoon) and 193 days (second ratoon). Results showed that at first and second ratoon, plant height and tillering number were increased after 5 metric ton/ha biochar and 10 metric ton/ha manure additions (p < 0.05). Manure treatment resulted in higher crude protein content (p < 0.05) than controls at first and second ratoon stages. Combinations of biochar (p < 0.01) and manure (p = 0.09) improved in vitro gas production from the insoluble fraction (b). The study concludes that treatment with 5 metric ton/ha biochar and 10 metric ton/ha manure fertilizers on post-nickel-mining soil increases tillering number, height, CP content and in vitro digestibility of P. purpureum cv. Mott at ratoon stages. [ABSTRACT FROM AUTHOR]

Sustainable mine closure is one of the main priorities of the mining industry. This aim of this research was to predict the spatiotemporal development of water levels in a mined-out pit by generating forecasts of the dependent variables (rainfall and temperature) via linear (autoregressive integrated moving average) and non-linear (artificial neural network) models. We investigated natural water level development in one mined-out pit of the closed lignite mines in Amynteon, north Greece, with no artificial recharge. The forecasted rate of water level increase was estimated to be ≈ 10 m per year in the 'early' stage of pit lake spatiotemporal evolution (first 10 years), and 0.1 m per year in the 'last' stage of potential lake development (after year 2060). Also, the optimum lake surface (i.e. the level where no significant increase in water level rate appears) was estimated at + 520 m, which was predicted to occur in ≈ 40 years. The proposed methodology was validated via water level measurements performed during the first year of lake development, where field measurements of water elevations closely followed predictions. Forecasting pit lake water levels is essential for strategic planning, examining pit lake repurposing options, and informing decisions about post-mining futures and economic transitions. [ABSTRACT FROM AUTHOR]

The article presents three German-located case studies based on stochastic methods founded by the theory proposed by Knothe and the development of the 'Ruhrkohle method' according to Ehrhardt and Sauer. These solutions are successfully applied to predict mining-induced ground movements. The possibility of forecasting both vertical and horizontal ground movements has been presented in the manuscript, which allowed for optimization mining projects in terms of predicted ground movements. The first example presents the extraction of the Mausegatt seam beneath the district of Moers-Kapellen in the Niederberg mine. Considering, among others, the adaption of the dynamic impact of the underground operations to the mining-induced sensitivity of surface objects, the maximum permissible rate of the face advance has been determined. The second example presents the extraction of coal panel 479 in the Johann seam located directly in the fissure zone of Recklinghausen-North. Also, in this case, the protection of motorway bridge structure (BAB A43/L225) to mining influences has been presented. The Ruhrkohle method was used as a basis for the mathematical model that was developed to calculate the maximum horizontal opening of the fissure zone and the maximum gap development rate. Part of the article is dedicated to ground uplift due to rising mine water levels. Although it is not the main factor causing mining-related damage, such movements in the rock masses should also be predicted. As the example of the Königsborn mine, liquidated by flooding, shows stochastic processes are well suited for predicting ground uplift. The only condition is the introduction of minor adjustments in the model and the use of appropriate parameters. [ABSTRACT FROM AUTHOR]

The dewatering system of the Lipovsky nickel mining pit (Middle Urals, Russia) has performed a dual role. From 1961 to 1991, while nickel was being mined there, it protected the pit from flooding with groundwater; since 1989, it has been the principal source of drinking water for the town of Rezh (≈ 50,000 residents). After mining ceased, water withdrawal from the drainage wells decreased 2.5 times (to 100 L/s), resulting in a 120 m deep pit lake. A mass balance analysis has shown that water from the pit lake has become the leading source of water intake. However, the concentrations of the water's basic constituents at the eastern edge of the pit are several times higher than at the western edge. The reason for the significant increase in the water withdrawn by the wells of the western intake is the fact, that during the working of the main ore body, the eastern part of the pit was filled with overburden rock and substandard ore with dispersed sulfide mineralization. Flooding of the pit created a single aquifer between the pit lake and the eastern water intake facility, including an artificial aquifer within the refilled part of the pit. The rise of the groundwater level in the artificial aquifer to an elevation above 150 m (after 1994) led to active chemical weathering of sulfide-containing minerals and dissolution of secondary sulfates, which accounts for the increasing levels of constituents in the eastern part of the pit. The artificial aquifer has become a generator of salts. The dumping of sulfidic wastes and subsequent recovery of the water table have led to the release of sulfate, calcium, and metals into the local groundwater. To prevent the formation of an artificial aquifer, it is necessary to either completely remediate the unflooded portion using non-acid generating material or completely inundate the pit. Partial remediation would be the worst scenario as it could destabilize the hydrogeochemical processes and render long-term coexistence of the drinking water intake and the flooded pit problematic. [ABSTRACT FROM AUTHOR]

The damage caused by mining activities are usually environmental aesthetic disturbances (pits and voids), degradation of the existing topographic structure, the pollution of underground and surface water resources, the problems of dust in the living areas, the negativities in terms of life and property safety, the damages of the vital usage areas and the restriction of the living spaces. A methodology has been defined to determine the best future land use alternative for active marble mining sites. GIS, multi-criteria decision making method and fuzzy logic methods are used together to create a land use suitability model as a decision support tool. The study is limited to marble mining activity in the case study of Antalya, Burdur, and Isparta regions (Turkey). The model results give the best option among the alternative land use classes, agricultural areas (A), afforestation (F), recreational area (R), industrial area (I) and landfill area (L) for the 715 marble mines in the study area. [ABSTRACT FROM AUTHOR]

We tested the effect of main soil characteristics and tree species on earthworm community composition and abundance in reclaimed spoil heaps planted with five different tree species. Earthworm and soil macroarthropod abundance and biomass were highest in alder plantations, followed by oak plantations. The numbers of soil macrofauna were positively correlated with the total soil N content, which was highest in alder plantation. The correlation was strongest for endogeic earthworms (genus Aporrectodea and Octolasion). Soil moisture, measured in top 10 cm, affected only endogeic species. Other soil variables (pH, Ca) did not have a strong effect on earthworms. The earthworm community composition was similar in alder and oak, with most species occurring at both types of forest; however, in alder forest the epigeic species Dendrobaena octaedra was more common, whilst in oak forest the epigeic earthworms form genus Lumbricus were more abundant (L. rubellus and L. castaneus). The anecic species Aporrectodea longa was more abundant at alder sites, but L. terrestris was more abundant under oak. The alder forest was characteristic by a thick humus layer (10–15 cm), which at oak and larch sites was thinner (4–7 cm) and at pine and spruce stands was absent. Soil compaction was lower under the deciduous trees (alder, oak, larch), than under spruce and pine. We conclude that the alder plantations have most palatable litter and lowest C/N ratio and therefore support the highest numbers of soil macrofauna, which affects the humus layer thickness and soil compaction in the surface layers. [ABSTRACT FROM AUTHOR]

Deforestation and forest degradation are one of the most crucial issues in the forestry sector. The impact of deforestation and forest degradation due to the opening of forest areas for mining activities that causes damage to sustainable forest ecology. This condition requires companies as miners to carry out revegetation activities in post-mining areas to restore forest existence. PT. Vale of Indonesia (PTVI) is a nickel mining company located in Sorowako, South Sulawesi Province, which has carried out revegetation activities and is considered quite successful. This assessment has not included biomass as an indicator of forest productivity. Biomass is one of the determinants of forest productivity in post-mining areas needs to be further investigated to maximized revegation management. The objective of this study was to measure and construct a model for estimating biomass in the revegetation of the post-mining area in PTVI. The results of this study obtained a regression model of the rank as a biomass estimator in the revegetation of the post-mining area in PTVI. The form of the selected model equation is Y= 2,59505E-13 X1 2,489 X2 3,645. The independent variable is X1 = DVI (vegetation index) and X2 = C% (percentage of canopy). The regression model chosen has a determination coefficient of 70,60% and a standard deviation of -0,33528. [ABSTRACT FROM AUTHOR]

This contribution explores the potential of unmanned aerial systems (UAS) to monitor areas affected by acid mine drainage (AMD). AMD is an environmental phenomenon that usually develops in the vicinity of mining operations or in post-mining landscapes. The investigated area covers a re-cultivated tailing in the Sokolov lignite district of the Czech Republic. A high abundance of AMD minerals occurs in a confined space of the selected test site and illustrates potential environmental issues. The mine waste material contains pyrite and its consecutive weathering products, mainly iron hydroxides and oxides. These affect the natural pH values of the Earth's surface. Prior research done in this area relies on satellite and airborne data, and our approach focuses on lightweight drone systems that enables rapid deployment for field campaigns and consequently-repeated surveys. High spatial image resolutions and precise target determination are additional advantages. Four field and flight campaigns were conducted from April to September 2016. For validation, the waste heap was probed in situ for pH, X-ray fluorescence (XRF), and reflectance spectrometry. Ground truth was achieved by collecting samples that were characterized for pH, X-ray diffraction, and XRF in laboratory conditions. Hyperspectral data were processed and corrected for atmospheric, topographic, and illumination effects using accurate digital elevation models (DEMs). High-resolution point clouds and DEMs were built from drone-borne RGB data using structure-from-motion multi-view-stereo photogrammetry. The supervised classification of hyperspectral image (HSI) data suggests the presence of jarosite and goethite minerals associated with the acidic environmental conditions (pH range 2.3-2.8 in situ). We identified specific iron absorption bands in the UAS-HSI data. These features were confirmed by ground-truth spectroscopy. The distribution of in situ pH data validates the UAS-based mineral classification results. Evaluation of the applied methods demonstrates that drone surveying is a fast, non-invasive, inexpensive technique for multi-temporal environmental monitoring of post-mining landscapes. [ABSTRACT FROM AUTHOR]

Mining for resources extraction may lead to geological and associated environmental changes due to ground movements, collision with mining cavities, and deformation of aquifers. Geological changes may continue in a reclaimed mine area, and the deformed aquifers may entail a breakdown of substrates and an increase in ground water tables, which may cause surface area inundation. Consequently, a reclaimed mine area may experience surface area collapse, i.e., subsidence, and degradation of vegetation productivity. Thus, monitoring short-term landscape dynamics in a reclaimed mine area may provide important information on the long-term geological and environmental impacts of mining activities. We studied landscape dynamics in Kirchheller Heide, Germany, which experienced extensive soil movement due to longwall mining without stowing, using Landsat imageries between 2013 and 2016. A Random Forest image classification technique was applied to analyze land-use and landcover dynamics, and the growth of wetland areas was assessed using a Spectral Mixture Analysis (SMA).We also analyzed the changes in vegetation productivity using a Normalized Difference Vegetation Index (NDVI).We observed a 19.9% growth of wetland area within four years, with 87.2% growth in the coverage of two major waterbodies in the reclaimed mine area. NDVI values indicate that the productivity of 66.5% of vegetation of the Kirchheller Heide was degraded due to changes in ground water tables and surface flooding. Our results inform environmental management and mining reclamation authorities about the subsidence spots and priority mitigation areas from land surface and vegetation degradation in Kirchheller Heide. [ABSTRACT FROM AUTHOR]

Whether mining activity results in reduced flow of surface water in the Peace River Watershed of Florida has been the subject of much debate. With increased dependence of downstream users on surface water flow of the Peace River as a source of drinking water for four coastal counties in Southwest Florida and problems of water security, the debate has been intensified. It is possible to assess relationships of mining with streamflow in the upper reaches of the Peace River Basin using hydrologic modeling and identify mined sub-basins. In this work, land-use change impacts were simulated by the Hydrological Simulation Program-Fortran (HSPF) model based on geographical information system (GIS) tools, to compare pre- and post-mining streamflows at a study site of the Peace River in west-central Florida. The purpose of this study was to determine if land-use changes caused by mining have negatively impacted streamflow in the Peace River. Changes of land use were identified before and after mining activities. A coupled volume-water depth-discharge ( V-h-Q) model based on stage/storage and stage/discharge was applied using HSPF for the pre-mining and post-mining models, respectively. Daily simulated post-mining hydrographs from HSPF were plotted with the calibrated pre-mining results and streamflow hydrographs from the 18 gauging stations, to compare timing of peaks, low flows and flow trends. Analyses of percent exceedances of flow frequency curves of the streams indicated that most streams had similar distributions for mined (reclaimed) and premining periods. In the streamflow change analysis, streamflows actually increased in mining-affected basins at nearly half the stations. Streamflows at other stations diminished. Overall from this comprehensive study, there were declines in streamflow at most gauging stations on the mainstem of the Peace River and its tributaries. The results of this study suggest that regional planning is urgently needed to propose reclamation schemes that enhance regional hydrology. [ABSTRACT FROM AUTHOR]

Ecological restoration of degraded metal-rich habitats and bare metal-rich soils created by mining activities has nowadays become a major environmental issue to reduce mining impacts on the erosion of biodiversity and the degradation of landscape, soil and water. Studies based on species identification for restoration purposes without reference to plant trait are limited only to local pool of species which makes the interpretation and applications in various ecological contexts rather difficult. This study aims at trait analysis of metal-rich habitats in order to test the differences in plant traits in degraded primary habitat and along a successional gradient in secondary habitats. In this context, investigation of the existence of resilience or the need for ecological restoration is attempted. A second aim of this work is also the identification of traits candidates for appropriate species selection for revegetation of metal-rich bare soils purposes. Results showed that the cover of xylopodia trait values decreases according to the intensity of degradation among habitats, and can be considered an indicator of habitat degradation. Differences of traits values among primary and old secondary habitats highlighted that the absence of resilience of degraded primary steppic savanna was not explained by 14 soil factors measured. The main plant traits for revegetation of metal-rich bare soils are the following: annual life cycle, growth phenology in wet season, depth 0–10 cm of underground system , bud bank by seeds, dispersule size <2 mm × 2 mm and dispersal mode by adhesion. Future challenge would be to develop new functional ecosystem on metal-rich bare soils promoting biodiversity conservation and ecosystem services related to water and soil protection. This would require the association of species selected for revegetation and phytostabilization from plant traits occurring in secondary metalliferous habitats and species selected from plant traits specific to primary habitats. [ABSTRACT FROM AUTHOR]

In this paper we demonstrate how recent geomodelling techniques can be combined and used to build a 3D geological model on a real case study: the former coal mine of Merlebach (France), that is targeted to be exploited for low-temperature geothermal energy production. From geological maps, cross-sections, borehole and mine exploitation data, we build a 3D model in which are identified the rocks and infrastructures having significantly different permeabilities. First, a structural model of the main geological interfaces in our area of interest (2 horizons and 13 faults) is built with classical geomodelling techniques. Then, we propose to model by surfaces the 71 irregularly stacked, very close and very thin, sub-vertical coal beds. To ease their construction, we use an implicit method which represents 3D surfaces as isovalues of a scalar field defined in a 3D tetrahedral grid of the area. The corresponding triangulated surfaces are remeshed with a recently proposed method based on Voronoi diagrams so that the exploited parts of the coal beds, now filled by sand, can be computed. The 3D surface-based geological model, in which infrastructures can be inserted as piecewise lines, can be volumetrically meshed. It is available for download as supplemental material, as well as a volumetric grid. [ABSTRACT FROM AUTHOR]

In-situ recovery (ISR) of uranium (U) from sandstone-type roll-front deposits is a technology that involves the injection of solutions that consist of ground water fortified with oxygen and carbonate to promote the oxidative dissolution of U, which is pumped to recovery facilities located at the surface that capture the dissolved U and recycle the treated water. The ISR process alters the geochemical conditions in the subsurface creating conditions that are more favorable to the migration of uranium and other metals associated with the uranium deposit. There is a lack of clear understanding of the impact of ISR mining on the aquifer and host rocks of the post-mined site and the fate of residual U and other metals within the mined ore zone. We performed detailed petrographic, mineralogical, and geochemical analyses of several samples taken from about 7 m of core of the formerly the ISR-mined Smith Ranch–Highland uranium deposit in Wyoming. We show that previously mined cores contain significant residual uranium (U) present as coatings on pyrite and carbonaceous fragments. Coffinite was identified in three samples. Core samples with higher organic (> 1 wt.%) and clay (> 6–17 wt.%) contents yielded higher 234 U/ 238 U activity ratios (1.0–1.48) than those with lower organic and clay fractions. The ISR mining was inefficient in mobilizing U from the carbonaceous materials, which retained considerable U concentrations (374–11,534 ppm). This is in contrast with the deeper part of the ore zone, which was highly depleted in U and had very low 234 U/ 238 U activity ratios. This probably is due to greater contact with the lixiviant (leaching solution) during ISR mining. EXAFS analyses performed on grains with the highest U and Fe concentrations reveal that Fe is present in a reduced form as pyrite and U occurs mostly as U(IV) complexed by organic matter or as U(IV) phases of carbonate complexes. Moreover, U–O distances of ~ 2.05 Å were noted, indicating the potential formation of other poorly defined U(IV/VI) species. We also noted a small contribution from U O at 1.79 Å, which indicates that U is partially oxidized. There is no apparent U–S or U–Fe interaction in any of the U spectra analyzed. However, SEM analysis of thin sections prepared from the same core material reveals surficial U associated with pyrite which is probably a minor fraction of the total U present as thin coatings on the surface of pyrite. Our data show the presence of different structurally variable uranium forms associated with the mined cores. U associated with carbonaceous materials is probably from the original U mobilization that accumulated in the organic matter-rich areas under reducing conditions during shallow burial diagenesis. U associated with pyrite represents a small fraction of the total U and was likely deposited as a result of chemical reduction by pyrite. Our data suggest that areas rich in carbonaceous materials had limited exposure to the lixiviant solution, continue to be reducing, and still hold significant U resources. Because of their limited access to fluid flow, these areas might not contribute significantly to post-mining U release or attenuation. Areas with pyrite that are accessible to fluids seem to be more reactive and could act as reductants and facilitate U reduction and accumulation, limiting its migration. [ABSTRACT FROM AUTHOR]

Abstract: Tunisia is submitted to numerous small topographic displacements due to both the geodynamic of the Eurasian-African plates’ convergence, and to important anthropic actions such as oil production, underground water pumping, mine extraction and linked post-mining displacements. We propose herein to study the latter and locate, characterize, and quantify small topographic displacement fields due to the production of underground phosphate mines in central Tunisia. After having acquired and processed 17 radar images (ERS 1 and 2) of the central Tunisia (Gafsa area) through Differential Interferometry (DInSAR), we clearly observed local subsidence that we interprete as corresponding to mine exploitation of the underground Moulares Phosphates mines (southern Atlas of Tunisia). Field studies (circular normal faults located above the Phosphate extraction area) confirm the movement revealed by DinSAR. Also, DInSAR allows us to monitor temporal variations of the small vertical displacements on this specific area and since the collapse occurred near an urban area (Moulares city), this problem can be considered a potential anthropic risk. [Copyright &y& Elsevier]

The paper presents aspects of research that takes into account surface instability phenomena, arising from the mining of iron ore Iara -Baisoara deposit, emphasizing the Masca- Baisoara area. Based on the geo - mechanical characterization, the rock stability in the underground workings was assessed. It was also carried out an analysis concerning the rock displacement phenomenon around the underground cavities resulted after mining activity and the analysis of the surface land evolution in time. Finally we forecasted the evolution of these phenomena on account the surface stability monitoring. [ABSTRACT FROM AUTHOR]

The interferometric synthetic aperture radar (InSAR) technique is used to detect surface deformations in the French Nord-Pas-de-Calais coal mining basin. Several subsiding areas had already been observed at the sites of Lens, Billy-Montigny, Courrieres and Ostricourt during the 1992-2000 period. InSAR deformation measurements are compared with ground-based levelling measurements and an analysis of the results shows a good agreement for the relative deformations. However, the InSAR study reveals a systematic bias of the absolute levelling values. Our interpretation is that the stability points of the ground-based monitoring network probably moved during the study period. Such cross-checking is particularly important considering the current legal value of the levelling measurements. [ABSTRACT FROM AUTHOR]

This paper proposes a new strategy for maintaining association rules in dynamic databases. This method uses weighting technique to highlight new data. Our approach is novel in that recently added transactions are given higher weights. In particular, we look at how frequent itemsets can be maintained incrementally. We propose a competitive model to ‘promote’ infrequent itemsets to frequent itemsets, and to ‘degrade’ frequent itemsets to infrequent itemsets incrementally. This competitive strategy can avoid retracing the whole data set. We have evaluated the proposed method. The experiments have shown that our approach is efficient and promising. [Copyright &y& Elsevier]

Abstract In Maputaland, South Africa vegetative and microclimatic changes on mined dunes drive the composition of the dung beetle fauna toward convergence with that in natural dune forest on unmined dunes. We assessed the pattern of these changes using a 23-year vegetational chronosequence on mined dunes, which passes from grassland (approximately 1 year) to open Acacia shrubland thicket to Acacia karroo -dominated woodland (approximately 9 years). Across this sequence, which represents successional stages in the restoration of dune forest, there was a sequential trend toward convergence in dung beetle species composition in both the entire species complement and, particularly, in shade specialist species. However, species abundance patterns showed a trend toward convergence only in early chronosequence Acacia woodland, followed by a decline in similarity between dung beetle assemblages of older Acacia woodland and unmined natural forest. This trend toward divergence was common both to the entire species complement, which includes widespread taxa, and to species endemic to Maputaland or the east coast. These trends in similarity and dissimilarity between dung beetle assemblages closely parallel the greater physiognomic and microclimatic similarity between early Acacia woodland and natural forest and the relative dissimilarity of older Acacia woodland. In conclusion, although percentage similarities between dung beetle assemblages of approximately 12-year woodland and natural forests were comparable with those between each natural forest stand, decline in similarity in older woodland stands suggests that lasting convergence in dung beetle species abundance will only be attained once the Acacia woodland is replaced by secondary natural forest. [ABSTRACT FROM AUTHOR]

The article discusses the history of coal mining in Germany including the establishment of RAG Aktiengesellschaft, the formation of RAG Stiftung foundation and the development of optimized mine water concepts.

The exposure of metal sulfides to air or water, either produced naturally or due to mining activities, can result in environmentally damaging acid mine drainage (AMD). This needs to be accurately monitored and remediated. In this study, we apply high-resolution unmanned aerial system (UAS)-based hyperspectral mapping tools to provide a useful, fast, and non-invasive method for the monitoring aspect. Specifically, we propose a machine learning framework to integrate visible to near-infrared (VNIR) hyperspectral data with physicochemical field data from water and sediments, together with laboratory analyses to precisely map the extent of acid mine drainage in the Tintillo River (Spain). This river collects the drainage from the western part of the Rio Tinto massive sulfide deposit and discharges large quantities of acidic water with significant amounts of dissolved metals (Fe, Al, Cu, Zn, amongst others) into the Odiel River. At the confluence of these rivers, different geochemical and mineralogical processes occur due to the interaction of very acidic water (pH 2.5–3.0) with neutral water (pH 7.0–8.0). This complexity makes the area an ideal test site for the application of hyperspectral mapping to characterize both rivers and better evaluate contaminated water bodies with remote sensing imagery. Our approach makes use of a supervised random forest (RF) regression for the extended mapping of water properties, using the samples collected in the field as ground-truth and training data. The resulting maps successfully estimate the concentration of dissolved metals and related physicochemical properties in water, and trace associated iron species (e.g., jarosite, goethite) within sediments. These results highlight the capabilities of UAS-based hyperspectral data to monitor water bodies in mining environments, by mapping their hydrogeochemical properties, using few field samples. Hence, we have demonstrated that our workflow allows the rapid discrimination and mapping of AMD contamination in water, providing an essential basis for monitoring and subsequent remediation. [ABSTRACT FROM AUTHOR]

Knowledge on the bioavailability of trace elements is essential in developing environmental quality standards. The purpose of this study was to explore the relationships between trace elements (in particular Uranium (U)) in sediments, porewater and their bioaccumulation by Chironomus riparius on a uranium mining site and river sediments upstream of the mine. The mobility and speciation of U in sediments was investigated using DGT. Geochemical modelling using CHESS provided insight on sorption behavior of U on ironoxyhydrite (HFO) and aqueous speciation of U. In the upstream site U concentrations found were 0.05 μmol g−1 in surface sediment, 0.84 nmol L−1 in porewater and 2.4 nmol g−1 in Chironomus riparius whereas in the ferrihydrite deposits on the mining sites the concentrations found were up to 9.4 μmol g−1 in surface sediment, 0.37 μmol L−1 in porewater and 0.684 μmol g−1 in in Chironomus riparius. Despite the large differences in concentrations of U between the two sites, sediment to dissolved partitioning coefficients, bioconcentration factor (BCF) and biota sediment accumulation factors (BSAF) were very comparable. In the upstream sediment binding of U to organic matter controls sorption and aqueous speciation of U, whereas in the HFO rich sediments, sorption on HFO and the formation of HFO colloids are the determining factors. The low BSAF factors and high BCF factors indicate that the bioaccumulation is due to uptake from the dissolved phase. The DGT probes with different binding resins provide information on the colloidal nature and lability of the dissolved U species. Image 1 • Bioaccumulation of U in mining sediments and an upstream site was investigated. • Low BSAF and high BCF at both sites were observed. • Sorption of U on ironoxyhydrite and organic matter control speciation and bioavailability. • DGT provides information on colloidal fraction and labile U-species. [ABSTRACT FROM AUTHOR]