Search

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]

In an Afrotropical region experiencing massive deforestation, restoration approaches should provide sustainable solutions for recovering biodiversity. Arthropods are a sensitive taxonomic group for habitat alteration by deforestation and can be good indicators for restoration studies. Ground-dwelling arthropods provide important ecosystem functions, such as predation or organic matter decomposition, thereby contributing to ecosystem functionality. The consequences of post-mining management on arthropods in the Afrotropical region remain understudied. We carried out a comprehensive sampling of ground-dwelling arthropods in the dry and wet seasons across four land-use types in the semi-deciduous forest zone of Ghana. We then analysed whether the specific tree communities, vegetation structure and seasonal differences affected arthropod communities in the restored post-mining forest compared to the dominant alternative land-use type (agroforestry plantation), a natural reference (natural forest) or an unmanaged former mining area (gravel mine). In total, 43,364 arthropods were sampled and assigned to 78 taxonomic groups representing 14 order/sub-order, 28 beetle families, 25 spider families, 5 hunting guilds of spiders and 6 trophic groups of beetles. Overall, Araneae, Coleoptera, Hymenoptera and Orthoptera all had higher activity densities in the wet season. The vegetation structure of the three land-use types with trees supported a greater overall activity density of arthropods and a more diverse functional composition compared to the unmanaged gravel site. Pronounced variation between the dry and wet seasons further influenced the taxonomic and functional composition. The active forest restoration of this post-mining area is a promising approach to drive arthropod communities towards a comparable state observed in the natural forest. [ABSTRACT FROM AUTHOR]

In this study, leaves of the evergreen holm oak Quercus ilex were used to assess airborne contamination of potentially toxic elements (PTEs) at five towns located on the slopes of the Mt. Amiata (central Italy), an area with a long history of mining and, more recently, an important district for the industrial exploitation of geothermal energy. PTE composition and covariance of washed and unwashed Q. ilex leaves of three different ages (6, 12 and 24 month-old) were used to identify atmospheric inputs of PTEs at residential areas, evaluate long-term adsorption and retention of PTEs by the leaves, thus providing an indication of potential human exposure. Moreover, the determination of foliar concentrations of major elements (C, N, S and P) allowed an assessment of the nutritional status of the investigated urban tree stands which excluded the existence of stress condition caused by air pollution or other disturbances. Results indicated that overall Pb, Cu, and Cd concentration were low in the investigated urban sites, if compared with similar studies conducted in larger Italian cities, denoting a low contribution of vehicular traffic to the atmospheric pathway. The five urban settlements were characterized by a specific profile of elements (Al, Ba, Hg and Sb) enriched in unwashed leaves, resulting from the distinct geochemical characteristics of the area and from diffuse (i.e., urban activity) and point sources of PTEs emission (i.e., brownfields, geothermal power plants). The latter sources primarily govern the distribution of Hg, whose contamination was found to be very localized close to a major abandoned mining area. Our data provided quantitative evidence of the spectrum of PTEs potentially impacting resident population and may prove useful in support of follow-up instrumental monitoring campaigns of air quality, as well as for human health and ecological risk assessments. [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]

Using post-mining areas for planting energy crops has emerged as a promising and sustainable reclamation solution due to its potential contributions to environmental protection, land restoration, and especially energy security. However, to ensure the sustainability of this reclamation solution, its environmental performance needs to be thoroughly assessed case by case. Located in Ha Thuong Commune, Dai Tu District, Thai Nguyen Province in northern Vietnam, Nui Phao is the world's largest tungsten mine. To restore post-mining sites at Nui Phao, cassava planting for ethanol production was one of the proposed measures. To support the decision-making, this study employs life cycle assessment to thoroughly evaluate the environmental performance and potential environmental benefits/costs of cassava-based reclamation system in terms of resource consumption and green house gas (GHG) emission. The results show that cassava-based reclamation might bring significant environmental benefits in terms of fossil fuel saving and GHGs reduction (i.e., reduce 50% fossil fuel consumption and 36% GHGs emission); however, it does not bring any benefit in terms of water and land resource consumption. Moreover, the results define cassava cultivation as the "hot spot" of the system, where innovations to enhance the yield and reduce water and fertilizer consumption are required to improve the environmental performance of the cassava-based reclamation system. [ABSTRACT FROM AUTHOR]

Copyright of Grundwasser is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

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]

In application at the Zlatna gold mining area (Apuseni Mountains, Romania), the correlation of water isotopes and geochemical data were successfully used to assess the genetic relationships between surface running water, groundwater and mine water, as well as to evaluate the mining effects on the surrounding environment after the cessation of mining operations. The majority of mine water sources display pH values between 4 and 5, i.e. acid mine water. The mine water characterized by slightly higher pH values (~6) interacts with ophiolitic rocks which have high pH buffering capacity. The neutral mine water (pH ~ 7) does not come into direct contact with reactive minerals, either because it is discharged from an exploration adit or because of the complete leaching of pyrite and other sulphides in old abandoned mining works. The later also shows low levels of heavy metals concentrations. Calcium is the dominant cation in mine water and in the majority of surface running water and groundwater sources, indicating the same mechanisms of mineralization. All mine water sources are $$\text{SO}_{4}^{2 - }$$ type and show very high $$\text{SO}_{4}^{2 - }$$ concentrations (6539 mg/l mean value). Surface and groundwater sources are classified either as $$\text{SO}_{4}^{2 - }$$ or as $$\text{HCO}_{3}^{ - }$$ type water. Linear correlation between δD and δO values indicates that all water sources belong to the meteoric cycle. Low δD and δO values of mine water (δD < −70‰; δO < −10‰) suggest snow melt and high-altitude precipitations as the main source of recharge. The mine water is less affected by the seasonal variation of temperature. In most cases, the variations in isotopic composition are within narrow limits (less than 1‰ for both δD and δO), and this result suggests well-mixed underground systems. Elevated concentration of sulphates, Zn and Fe in mine waters are the main issues of concern. For the study area, no relevant contamination of springs or phreatic water by mine water was revealed. On the contrary, surface running water is contaminated by mine water, and the negative effects of acid mine drainage occur mainly in the summer months when the flow of the surface running water decreases. [ABSTRACT FROM AUTHOR]

A practical issue is present in sustaining and rehabilitating the ecologically vulnerable post-mining area in which the environmental condition varies spatially and therefore influenced by multiple factors. This paper attempts to integrate the ecological vulnerability assessment and rehabilitation treatment to assist land managers in revealing vulnerable features along with developing treatments of vulnerability mitigation. Using a post-mining site in a mountainous area in western China as study area, an indicator system and framework for assessing and reducing vulnerability were developed based on a vulnerability analysis. Geo-informatics, such as satellite image processing and spatial analysis, were employed to perform the assessment and planning. It was found that higher exposure and sensitivity are the main causes of increased vulnerability in a seriously disturbed post-mining area. Rehabilitation treatments were arranged spatially and structurally based on the framework of vulnerability mitigation. A pre-evaluation of the effectiveness shows this type of rehabilitation has a convergence effect that clusters and lowers the ecological vulnerability index (EVI). The average value of EVI will be reduced by 15.02% if the minimum standards of rehabilitation can be completed. Altogether, an integration of rehabilitation treatments and the quantification of vulnerability in a spatially explicit manner are critical for planners to gain more insight into ecological vulnerability in post-mining area, which provides guidance to simplify rehabilitation planning with respect to vulnerability mitigation. [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]

Purpose: To assess how the rates of humus formation and humification are affected by land use and age of ecosystems, this study investigated soil development in two post-mining chronosequences (spoil heaps formed from open-cast coal mining near Sokolov, Czech Republic). The following characteristics were measured: content, composition, and properties of humic acids; organic carbon (C) and total nitrogen (N) contents; pH; and amorphous iron content. Materials and methods: Two chronosequences were studied. One consisted of unreclaimed spontaneously revegetated spoils (3, 12, 20, and 40 years old). The other consisted of heaps that were reclaimed by planting alder in graded heaps (7, 15, 20, 30, and 40 years old). Humus and iron contents as well as pH were determined, and humic acids were extracted for detailed chemical analyses (C, H, N, C-NMR, and pyrolysis mass-spectrometry). Results and discussion: C and N accumulated faster in the reclaimed sites than in the unreclaimed sites; organic matter accumulation results in the decrease of pH in all soils and in spontaneous sites also increase of amorphous iron content. Humic acids (HA) and fulvic acids (FA) increased with the site age in both chronosequences. The CHA/CFA was higher in the reclaimed soils than in the unreclaimed soils, and the CHA/CFA ratio increased with age in the unreclaimed soils. Humic acid aromaticity was higher in the reclaimed site than in the unreclaimed sites but increased with the age of unreclaimed sites. H and O content decreased with age of reclaimed soils. Humification led to an increase in HA caloricity in the reclaimed sites but not in unreclaimed sites because of the influence of residual wax-type substances in the unreclaimed sites. Degree of HA oxidation (ω) for the reclaimed plots was similar to that in typical zonal soils but was highly variable in unreclaimed soils. Conclusions: Relative to spontaneous revegetation in the unreclaimed sites, reclamation increased the rates of humus accumulation, humification, and humus acid transformations. The differences between reclaimed and unreclaimed sites, however, decreased with site age and were very small in 40-year-old sites. These differences correspond to the rapid colonization of the reclaimed sites and the slow colonization of the unreclaimed sites by soil biota. [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.

Confusion surrounding the definition and application of terminology in post-mining ecological repair has resulted in uncertainty for industry, the scientific community and regulators. This lack of clarity may underrepresent high aspirations or could be misused to disguise low aspirations and so is problematic for setting objectives, establishing goals and assessing recovery trajectories. We respond to a recently published analysis of the ecosystem repair literature, where we highlight inconsistencies stemming from inadequate reference to a large proportion of the restoration and rehabilitation literature. We outline increasingly well-accepted and internationally applied definitions concerning the restoration and recovery process and invite both the mining industry and policy-makers to re-examine their terminology in the interests of attaining an internationally agreed nomenclature. Clarity in the use and understanding of terminology will align post-mining targets with community expectation, enhance the capacity of the mining industry to understand and meet these targets, and foster better analysis and more industry-relevant discussion of recovery methodologies by the scientific community and practitioners. [ABSTRACT FROM AUTHOR]