Open cut coal mining in the Bowen Basin of central Queensland had disturbed in excess of 55,000 ha by the turn of the 21st century and 72,000 ha by 2006. Strong export demand in recent years (since approximately 2000) has led to greater production from existing mines and to a proliferation of new ones. Therefore, over the ensuing decades, the level of mining activity can be expected to increase substantially the areas of erstwhile agricultural land that are disturbed. As mines exhaust their resources, companies will be obliged to achieve acceptable end uses for the various domains at those sites. The possibility of having successfully rehabilitated domains at selected sites certified on a progressive basis holds some appeal. While all stakeholder groups find a return of the land to its prior use (extensive cattle-grazing) an appealing goal, mining companies walk a tight-rope. The legislation under which the early mines were established does not bind them as tightly to the environmentally friendly outcomes as applies to new mines. Nonetheless, recent legislative trends as well as companies’ own policies, encourage them to exceed society’s environmental expectations. Regardless of the end use that is designated, relinquishment is permitted only subject to a satisfactory assessment of the risks to its sustainability. Cattle-grazing is considered as a suitable end use, partly because the return of mined land to its prior use is preferred to its designation to some other use and partly because cattle could serve to reduce the bulk of pasture growth that occurs at some sites, reducing the risk of erosion if an intense fire were to occur followed by heavy rain. Graziers’ primary motivation for seeking tenure of mined land is financial. Factors that determine both a site’s productivity and its commercial ‘worthwhileness’ are examined in this research. The major focus of this research however, is the style of management that the custodial grazier may employ. Since any future custodian is likely to be a local landholder (perhaps the grazier family from whom the land was originally acquired for mining some decades earlier), it is the management style of local farmers that is of primary interest. Some graziers use the land more intensively than others: some with more sensitivity than others. Since the reconstructed landscape is inherently more fragile than undisturbed land, differences in management style could be critical to the sustainability of grazing. Factors driving, or at least being associated with, farmers’ land management decisions were identified from prior research as draft components of a risk assessment model for grazing. A survey of the characteristics and circumstances of Bowen Basin graziers was then conducted with a view to modelling their influence on graziers’ land management style. The survey ascertained the prior probabilities among the target graziers of the elements being modelled. An estimate of the role of these factors in shaping land management decisions was then obtained by eliciting the opinions of industry experts. These processes allowed development of a predictive model that estimates the likelihood of conservative and sensitive land management under various scenarios of site characteristics and grazier-based factors. Output from the model showed that the capital circumstances of a grazier’s business have an influence over the predicted management style of 25% of the difference between best-case and worst-case scenarios. There is a 17% greater likelihood of low-risk grazing where a grazier strongly wants tenure of the land for reasons that go beyond financial gain. The grazier’s underlying values and attitudes to land management account for a further 14%, followed by the operational structure of the business (12%), and the external climatic and economic environment (9%). Interventions that mining companies could implement to increase the likelihood of low-risk management has an influence of 23%. The credibility of the model’s output was evaluated by reference to real-life experiences of graziers who have managed cattle on mined land and their miner counterparts. Consistency of opinion among the consulted experts also contributed to the confidence that can be placed in the model’s findings. The model identifies the sources of risk if currently available mined land is used for grazing. It improves understanding of the situation in a holistic manner, and predicts the likelihood of low-risk grazing management under scenarios of interest to the user. The model identifies actions that mining companies could take to reduce risks associated with graziers’ management style. The model may also guide future rehabilitation work by highlighting features of rehabilitation that would make them more suited to commercially feasible and low-risk cattle production – or by purposefully and transparently planning for cattle-grazing not to be the designated end use.

Das niederländische Wirtschaftsministerium hat 2014 eine umfassende Studie über alle zukünftig noch sicherheitlich relevanten Themenbereiche des Nachbergbaus für das Südlimburger Steinkohlenrevier beauftragt. Der Bergbau wurde hier bis 1974 stillgelegt; der Grubenwasseranstieg ist aber aufgrund der hydraulischen Verbindungen zu dem erst in 1992 stillgelegten Aachener Steinkohlenrevier noch nicht abgeschlossen. Der Auftrag wurde an ein deutsch/niederländisches Projektteam vergeben, das sowohl detaillierte Kenntnisse der regionalen Hydrogeologie besitzt als auch eine Bearbeitung von Fragestellungen im Zusammenhang mit Risiken durch bergbauliche Hinterlassenschaften auf dem aktuellen Stand der Technik und nach neuesten Forschungsergebnissen gewährleisten konnte. Auf der Grundlage einer umfassenden Bestandsaufnahme sowie einem regionalen Grundwassermodell wurden eine Risikobewertung vorgenommen und Konzepte für Maßnahmen und ein Monitoring erarbeitet. Die Studie wurde Ende 2016 veröffentlicht; der vorliegende Beitrag liefert eine Zusammenfassung der Ergebnisse und Empfehlungen. / The Ministerie van Economische Zaken (EZ) of the Netherlands in 2014 initiated the project „Na-ijlende gevolgen steenkolenwinning Zuid-Limburg“ and commissioned a comprising study considering all future safety aspects with respect to the potential consequences of the former hard coal exploitation in South Limburg. The coal mines were abandoned until 1974; due to hydraulic connections to the Aachen mining district, that was abandoned in 1992, the rise of the mine water has not finished yet. The study was assigned to a German-Dutch project group with comprising references of the regional Hydrogeology as well as excellent expertise in all questions regarding risks from mining relicts. Based on a comprising inventory and a regional groundwater model a risk assessment was carried out and a concept for measures and monitoring elaborated. The study was published in 2016; the paper in hand provides a summary of the results and recommendations.

L'étude des signes précurseurs d'un effondrement brutal au-dessus de cavités souterraines, dont le recouvrement est caractérisé par la présence d'un banc massif et raide, est un problème majeur pour la sécurité publique. Aussi, pour progresser dans la compréhension et l'évolution des mécanismes mis en jeu, une cavité saline, située dans le NE de la France, a été suivie en temps réel, entre 2004 et 2009, jusqu'à son effondrement. Celle-ci a été exploitée par dissolution, jusqu'à atteindre une dimension critique (de l'ordre de 180 m) sous un recouvrement de 180 m, armé d'un banc raide de Dolomie situé à 120 m de profondeur.Un système de mesures multi-paramètres haute résolution visait à caractériser les signes précurseurs ainsi qu'à suivre l'effondrement lui-même. Il comprenait des dispositifs à la fois géotechniques et géophysiques, dont des mesures de nivellement de surface et un réseau permanent d'écoute microsismique. Ce dernier, dont les données font l'objet principal de cette thèse, était constitué de neuf sondes équipées de géophones 40 Hz (5 unidirectionnels et 4 tridirectionnels), réparties autour et à l'aplomb de la cavité, dont une dans le banc raide.L'évolution de la cavité a été marquée par deux épisodes majeurs d'activité microsismique :- au printemps 2008, la reprise de la dissolution dans la cavité a engendré l'apparition de crises répétées avec plusieurs milliers d'événements en quelques jours, traduisant un changement de régime microsismique, marqueur de l'instabilité de la cavité ;- en février 2009, suite à ces observations, l'exploitant a décidé de provoquer l'effondrement, par le rabattement intensif de saumure dans la cavité. Pendant les trois jours d'opération, plus de 30000 événements ont été enregistrés (sur 60000 depuis 2004).L'étude de la signature des événements apporte des renseignements essentiels pour la surveillance opérationnelle et la discrimination de ces deux périodes. En particulier, alors que les valeurs maximales atteintes en amplitude, énergie au capteur et fréquence fondamentale apparente, sont assez stables au cours des crises, les sauts marqués durant l'effondrement, permettent de présumer de son imminence. L'évolution de la distribution des microséismes en termes d'énergie libérée et d'occurrence, calculée de manière similaire à la loi de Gutenberg-Richter, bien que souvent difficile à interpréter, a pu être associée à des hausses du niveau piézométrique, ainsi qu'à de petites accélérations de l'affaissement mesuré en surface. Pendant la période d'effondrement, le nombre d'événements microsismiques augmente en suivant une loi en puissance.La localisation des microséismes a nécessité la mise en place d'une stratégie adaptée pour garantir la qualité et l'homogénéité des résultats (sélection des enregistrements, calibrage, étude paramétrique).Cependant, l'utilisation d'un modèle de vitesse constant sur toute la période s'est révélé impossible, compte tenu de l'évolution rapide et permanente du milieu. Il a donc été entrepris d'établir des modèles de vitesse différents en fonction des périodes d'évolution de la cavité.Les distributions spatio-temporelles des foyers ainsi localisés montrent l'existence de structures préférentielles de rupture et souligne le rôle majeur du banc raide.Croisées avec les autres mesures acquises sur le site, ces résultats ont permis d'établir un scénario probable d'évolution de la cavité et de proposer quelques recommandations pour la surveillance opérationnelle / The study of the precursory signs of a brutal collapse above underground caverns, with an overburden characterized by the presence of a massive and stiff bench, is a major problem for public safety. Thus, to progress in the comprehension and the evolution of the concerned mechanisms, a salt cavern, located in the NE France, was monitored in real-time, since 2004 to 2009, until its collapse. This cavern was mined by solution, until reaching its critical dimension (about 180 m) under a covering of 180 m thick, armed with a stiff Dolomite bench located at 120 m of depth.A multi-parameter high resolution monitoring system aimed at characterizing the precursory signs and following collapse itself. It included both geotechnical and geophysical devices as surface leveling measurements and a permanent microseismic network. This one, which data are the principal subject of this thesis, consisted in nine probes equipped with 40 Hz geophones (5 1D and 4 3D), distributed around and directly below the cavern, including one located in the stiff bench.The evolution of the cavern was marked by two major episodes of microseismic activity:- at the beginning of spring 2008, the dissolution restart in the cavern which caused repeated crisis with several thousand events in a few days, this represent a change in the microseismic regime and marked the cavern instability;- in February 2009, following these observations, the owner decided to trigger the collapse by intensive brine pumping in the cavern. During the three days of the operation, more than 30,000 events were recorded (against 60,000 since 2004).The study of the event signature provides essential information for operational monitoring and the discrimination of these two periods. Particularly, while maximal values reached in amplitude, energy and apparent fundamental frequency are quite stable during the 2008 episodes, the rises of this values are important during the collapse period (prior to the peak of activity), allowed us to suppose its imminence. The evolution of the microseism distribution in terms of energy released and occurrence, calculated similarly to the Gutenberg-Richter law, although often difficult to interpret, has been associated with piezometric level rises, and with small accelerations of surface subsidence. During the collapse, the microseismic activity acceleration follows a power law.Microseisms location required the establishment of an appropriate strategy to ensure the quality and the consistency of the results (record selection, calibration, parametric analysis). However, the use of a constant velocity model over all the period was impossible due to the fast and permanent evolution of the environment. Thus, several models were used, according to the a priori known cavern evolution.The event spatiotemporal distributions, thus located, revealed the existence of preferential failure structures and highlight the role of the stiff bench, located at 120 m depth

The paper follows up on previous analyses of changes in soil microstructure in the process of soil development on dumps around Sokolov, Czech Republic, using the soil thin section method. The distribution of structures in the topsoil of the profile was studied in two chronosequences, one overgrown with spontaneous vegetation and one reclaimed by alder planting. A comparison with historical data obtained at these locations 10 years ago was used, and, therefore, the same methods were also applied (Frouz et al., 2007b). The most distinct trend in the process of soil development over time, as observed through both a comparison of soil thin sections from various areas of chronosequence and changes in particular sites over time, is a gradual reduction of purely mineral structures and their replacement by organic matter - litter and its fragments, faecal pellets of arthropods, earthworms coprolites, and roots. This is illustrative of a high share of biogenic structures and a fundamental contribution of organisms to forming topsoil, a fact also pointed out by other authors. Keywords: Soil macrofauna; Soil microstructure; Soil thin section; Reclamation; Post-mining sites; Soil development; Earthworms

Thesis (LLM) -- University of Limpopo, 2012 / The study focuses on rehabilitation, since absence of proper rehabilitation process result in indelible damage to the environment. South Africa, like many other countries, is faced with many environmental problems caused by mining. These problems are particularly caused by, inter alia, abandoned mining areas without rehabilitation, inadequate environmental impact assessment after closure, inadequate financial provision for rehabilitation, and lack of monitoring and aftercare system after post mine closure. The study found that many Companies ignore laws governing prospecting, extraction and rehabilitation. The main purpose of this research is to investigate and recommend guidelines in the rehabilitation process so as to instil respect for the environment. The study therefore recommended strict legislation relating to environmental protection against mining.

Due to coal mining activities, heap substrates rich in clays with poor water permeability and lack of nutrients are relocated outside of mines representing hostile environment to the majority of vegetation. A material from the surface coal mines in Sokolov forming the Velká Podkrušnohorská Heap (VPS) form large locality showing characteristics of anthropogenically devasted landscape. The aim of the present study was to compare leaf structural and biochemical parameters with relation to a leaf reflectance of two pioneer tree species Salix caprea and Populus tremula with regard to leaf water regime and leaf adaptation to a water loss. From the methodological point of view, the study aimed on contribution to determine relation of selected leaf structural parameters to leaf reflectance what has not been intensively studied yet. The foliage of trees P. tremula and S. caprea grown on succession localities S2 a S3 for 30 years was used as a material for my study. The material was studied for its structure using the leaf cross sections nd abaxial epidermal strips (thickness of the leaf tissue layers and of a leaf, stomatal size density and area). Other studied parameters were contents of photosynthetic pigments, specific leaf area (SLA), water potential and leaf reflectance in regions of photosyntetically...

Das niederländische Wirtschaftsministerium hat 2014 eine umfassende Studie über alle zukünftig noch sicherheitlich relevanten Themenbereiche des Nachbergbaus für das Südlimburger Steinkohlenrevier beauftragt. Der Bergbau wurde hier bis 1974 stillgelegt; der Grubenwasseranstieg ist aber aufgrund der hydraulischen Verbindungen zu dem erst in 1992 stillgelegten Aachener Steinkohlenrevier noch nicht abgeschlossen. Der Auftrag wurde an ein deutsch/niederländisches Projektteam vergeben, das sowohl detaillierte Kenntnisse der regionalen Hydrogeologie besitzt als auch eine Bearbeitung von Fragestellungen im Zusammenhang mit Risiken durch bergbauliche Hinterlassenschaften auf dem aktuellen Stand der Technik und nach neuesten Forschungsergebnissen gewährleisten konnte. Auf der Grundlage einer umfassenden Bestandsaufnahme sowie einem regionalen Grundwassermodell wurden eine Risikobewertung vorgenommen und Konzepte für Maßnahmen und ein Monitoring erarbeitet. Die Studie wurde Ende 2016 veröffentlicht; der vorliegende Beitrag liefert eine Zusammenfassung der Ergebnisse und Empfehlungen. / The Ministerie van Economische Zaken (EZ) of the Netherlands in 2014 initiated the project „Na-ijlende gevolgen steenkolenwinning Zuid-Limburg“ and commissioned a comprising study considering all future safety aspects with respect to the potential consequences of the former hard coal exploitation in South Limburg. The coal mines were abandoned until 1974; due to hydraulic connections to the Aachen mining district, that was abandoned in 1992, the rise of the mine water has not finished yet. The study was assigned to a German-Dutch project group with comprising references of the regional Hydrogeology as well as excellent expertise in all questions regarding risks from mining relicts. Based on a comprising inventory and a regional groundwater model a risk assessment was carried out and a concept for measures and monitoring elaborated. The study was published in 2016; the paper in hand provides a summary of the results and recommendations.

Aktuelle Risikomanagementsysteme verfolgen primär das Ziel, die Vielzahl notwendiger Maßnahmen zur Verwahrung altbergbaulicher Risikoobjekte objektiv und eindeutig zu priorisieren. Unterschiedliche Objektarten werden in separaten Systemen behandelt, auch wenn sich deren Auswirkungen an der Tagesoberfläche regelmäßig überlagen. In der Praxis zeigt sich dies, wenn in großflächigen Maßnahmen viele Objekte gemeinsam bearbeitet werden. Die Limitierung vorhandener interner und externer Ressourcen und die daraus resultierende lange Dauer bis zur Verwahrung aller Risikoobjekte ist der Grund für die Vorgehensweise. Auch wenn die operative Verwahrung schon wegen des Aufwands prioritär erscheint, ist das Ziel die maximale Reduzierung des Gesamtrisikos bei optimaler Nutzung vorhandener Ressourcen. In diesem Beitrag wird eine ganzheitliche Behandlung der altbergbaulichen Risiken vorgestellt. Die Einführung einer linearen Superposition ermöglicht eine modulare Vorgehensweise zur Integration unterschiedlicher Sachverhalte und Objekte in einem System. Neue Erkenntnisse können eingeführt werden, auch wenn sie nur einzelne Risikosachverhalte betreffen. Dabei reichen oft wenige geometrische Parameter, die aus dem markscheiderischen Risswerk oder Sanierungsmaßnahmen abgeleitet werden können. Eine rasterbasierte Berechnung des Risikos aus dem übertägigen Gefährdungspotenzial (= Stärke des Ereignisses) und der Sensibilität der Oberfläche (= Schadensausmaß) ermöglicht es, sinnvolle Bearbeitungsbereiche abzugrenzen. Dabei berücksichtigt eine normalverteilte Nachbarschaftsfunktion die Mobilität der Menschen, um deren Schutz es ja letztlich geht. Die flächennormierte Risikozahl wird zentraler Parameter für eine stets eindeutige Priorisierung. Die im vorliegenden Beitrag vorgestellte Lösung zur ganzheitlichen Bearbeitung altbergbaulicher Risiken wurde ausführlich in der Dissertation (S. Hager, 2022: Integrierte Bewertung altbergbaulicher Risikoobjekte des Steinkohlenbergbaus der RAG AG, TU Freiberg) beschrieben und war Gegenstand eines Vortrags beim Altbergbaukolloquium 2022 in Freiberg.

Durch die Flutung stillgelegter Tagebaue entstehen zahlreiche Seen in den ostdeutschen Braunkohlerevieren. Sie sind überwiegend groß, oligo- bis mesotroph, und ihr Litoral ist nur in geringem Umfang durch Makrophyten strukturiert. Viele von ihnen sind versauert oder versauerungsgefährdet. In einer Feldstudie wurden (1) die Auswirkung von Seemorphologie und Habitatstruktur auf die Fischgemeinschaft des Senftenberger Sees, eines 1050 ha großen mesotrophen Tagebausees, und (2) die Säuretoleranz einheimischer Fischarten unter den hydrochemischen Bedingungen der geogen versauerten Tagebauseen untersucht. Die Fischgemeinschaft des Senftenberger Sees wurde von Barschen (Perca fluviatilis) und Plötzen (Rutilus rutilus) dominiert, wobei die verschiedenen Barsch- und Plötzengrößenklassen ihre Habitate durch Nutzung verschiedener Tiefenbereiche des Litorals segregierten. Innerhalb der flachen Litoralbereiche waren juvenile Plötzen und juvenile Güstern deutlich stärker auf die wenigen Makrophytenbestände fixiert als juvenile Barsche. Die Habitatwahl der Barsche zeigt, dass diese in mesotrophen Seen wahrscheinlich eher von den guten Sichtverhältnissen als von der strukturellen Komplexität submerser Makrophytenbestände profitieren. Als Ursache für die unterschiedliche Habitatwahl juveniler Barsche, Plötzen und Güstern wird postuliert, dass diese generell verschiedene Habitatwahlstrategien verfolgen. Während der entscheidende Parameter für die Habitatwahl juveniler Barsche die Optimierung der Energieaufnahme ist, folgen juvenile Plötzen und Güstern vorrangig einer Räubervermeidungsstrategie und sind daher sehr viel stärker auf strukturreiche Bereiche angewiesen. Die kritischen pH-Untergrenzen für die einzelnen Fischarten entsprachen weitgehend den publizierten Ergebnissen aus regenversauerten Weichwasserseen. Vermutlich wurde in den Tagebauseen der Säurestress, den die erhöhte Al-Konzentration von bis zu 0,6 mg/L verursachte, durch die ebenfalls erhöhte Ca-Konzentration kompensiert. / Numerous post-mining lakes are created by flooding the pits remaining from open-cast lignite mining in eastern Germany. They are typically large, oligo- or mesotrophic and only sparsely structured by macrophytes. Many of them are acidified or at risk of acidification. The aim of this study was (1) to determine the effects of lake morphology and habitat structure on the fish community of Lake Senftenberg, a large mesotrophic post-mining lake, and (2) to determine the acid tolerance of indigenous fish species under the hydrochemical conditions of geogenically acidified post-mining lakes. The most abundant fish species in Lake Senftenberg were Eurasian perch (Perca fluviatilis) and roach (Rutilus rutilus). Different size classes of both species segregated along a depth gradient within the littoral zone. Unvegetated shallow littoral areas (depth 1-3 m) were mainly used by juvenile perch, whereas juvenile roach and juvenile white bream (Blicca bjoerkna) preferred macrophyte stands. This indicates that the structural complexity of submersed macrophytes is not the key factor favouring perch over roach under mesotrophic conditions. Instead, low turbidity is probably the most important factor. The habitat choice of juvenile perch, roach and white bream is suggested to reflect different habitat selection strategies. Whereas habitat selection of juvenile perch is predominantly driven by maximisation of food consumption rates, juvenile roach and juvenile white bream aim at minimising predation risk. Consequently, they are much more dependent on structurally complex habitats. The critical lower pH-thresholds of the fish species investigated in this study were similar to the values derived from soft water lakes affected by acid rain. The deleterious effects of elevated Al-concentrations (up to 0.6 mg/L) in the post-mining lakes were probably mitigated by high Ca-concentrations.

The ground beetles are one of the most worthwhile model groups of organisms for the indication of quality of environment due to their advantages such as simple identification, well known ecology of most species and described distribution. In this thesis I present the suitability of assemblages of ground beetles to evaluate the conservation value in two types of environment: (1) open forest in medium and lower altitudes, (2) post-mining biotopes as quarries and black coal dumps. I also discuss possible limitation of ground beetles as valid bioindicators and I recommend multi-taxonomical approach in ecological studies.