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The study of ancient disused mining contexts in the Mediterranean region is particularly challenging due to the impact of modern reclamation works and the presence of dense vegetation, which impede the application of conventional archaeological research methods. Pivoting on the multidisciplinary approach driven by the ERC nEU-Med project to the study of historical landscapes, and thanks to a new LiDAR survey promoted by the project in 2019, new investigations were carried out in ancient and modern mining contexts in the territory of Colline Metallifere (southern Tuscany, Italy). The district is renowned for its important metal deposits characterized by copper, lead, zinc and silver vein bodies that have been mined since the Bronze Age, with a particularly intense phase of exploitation during the Medieval period. The primary objective of the LiDAR DTM analysis was to map features and delineate the characteristics of the archaeo-mining landscape in five densely vegetated contexts. The analysis revealed numerous novel evidence related to mining activities (574 within the five territorial samples analyzed in this contribution), of which 72% were also inspected through fieldwalking surveys. These features have been interpreted by means of archaeological surveys, documentary research and statistical and spatial analysis. A particular focus was placed on the study of the most prevalent type of feature, which is the mining shaft. The development of reliable parameters of interpretation, including the dimensional aspects of each individual mining shaft (area, diameter and depth of the basin), the distances between shafts, and presence or absence of dumps, played a crucial role in disentangling the complex topography of the mining sites. The favourable results achieved through this study will enable the application of the method on a larger scale to other nearby mining contexts, overcoming the constraints of accessibility and visibility that have so far significantly influenced the analysis of mining territories. [ABSTRACT FROM AUTHOR]

• Past stone quarrying induced recent geomorphic processes with a delay of decades. • Tree rings verifies a higher rockfall rate in the quarry compared to natural cliffs. • Freeze-thaw cycles are the main trigger of rockfall in abandoned quarries. • Increased stem diameters of trees cause their more effective protective function. Abandoned quarries are a relatively common form of anthropogenic relief. The rocks disturbed by previous mining activities could foster conditions favourable for future dynamic geomorphic processes on quarry faces. Nevertheless, the activity of such processes, particularly that of rockfall, has not yet been studied in detail. This is of particular importance because human infrastructure is often still present in abandoned quarries, and rockfall can cause distinct natural hazards in such conditions. This study focuses on a multidisciplinary analysis of rockfall in selected abandoned quarry in the region of the Carpathians. A dendrogeomorphic analysis of 807 tree-ring series from 130 disturbed trees occupying the talus provided evidence of 264 tree injuries caused by falling rocks during the last 22 years. The reconstructed frequency of rockfall in quarries is several times higher than that of rockfall from natural localities within the studied region but also in Europe. Next, the seasonal dating of rockfall hits to trees displayed the prominence of such events during the tree dormancy period (ca. October to April), suggesting freeze–thaw cycles as the main trigger (the same as for natural localities in the region). Three species of broad-leaved trees of comparable age were used for the reconstruction, but no differences among the species were detected. The number of rockfall hits on tree trunks decreased significantly with increasing distance from the rockfall source zone, suggesting strong gradation of rockfall activity, compared to natural localities. Generally, the multidisciplinary results suggest very unstable conditions of rocks in abandoned quarries, predisposing them to frequent gravitational events. In contrast, ecological succession after mining termination gradually offers a protective function of trees. [ABSTRACT FROM AUTHOR]

Infrared field-based reflectance spectroscopy in the Visible - Near-Infrared - Short-wave Infrared (VIS-NIR-SWIR) domain is a useful tool in mining geology particularly efficient for investigating the clay mineralogy of alteration haloes around ore deposits. It is used as a routine technique for the basic identification, mapping and semi-quantification of clay mineral species. However, the use of this technique for prospecting in hypogene deposits at depth in intertropical areas is strongly limited because of the presence of a thick, kaolinite-rich lateritic cover. Due to the strong IR absorption of kaolinite and the overlapping of its IR bands with those of most of the phyllosilicates in the SWIR domain, the use of field based near-infrared spectroscopy does not permit efficient identification and mapping of the phyllosilicates inherited from hypogene alteration that persist in the saprolite of lateritic profiles. In this paper, we propose a methodology to enhance the detection and semi-quantification of hypogene phyllosilicate minerals in kaolinite-rich lateritic saprolites using calibration curves. Those curves are built from the NIR spectra of binary admixtures of kaolinite or smectite with muscovite, Fe-Mg chlorite, clinochlore or talc in different known proportions. For each admixture series, calibration curves were established, based on investigation of two regions of interest within the NIR domain (1350–1470 nm and 2080–2500 nm) using a field-based spectrometer. For each binary mixture series of phyllosilicates, the second derivative of the NIR spectra was used to enhance the detection of the diagnostic absorption bands of each type of phyllosilicate, and hence to optimize the calculation of the intensity ratios between the diagnostic bands of the phyllosilicate components as a function of their percentage in the mixture. In presence of large amounts of lateritic kaolinite, the detection limit of the major types of hypogene phyllosilicates has been found at ranges from 5 to 10 wt% of the total clay content using the second derivative of the NIR spectra acquired with a field-based spectrometer. Above these aforementioned limits of detection, the semi-quantitative data obtained by comparing the NIR reflectance spectra of natural samples with those of the calibration curves could permit to map hypogene alteration haloes directly from the lateritic saprolite. Finally the described approach has been successfully tested on natural samples from the skarn deposits of the Ity gold mine (Ivory Coast). [ABSTRACT FROM AUTHOR]

With increasing coal mining intensity, the number, length and depth of coal mine roadways is increasing drastically, the traditional drill-&-blast method and comprehensive mechanized driving method, and corresponding support methods are incapable of controlling the surrounding rock stability gradually. Hard rock TBMs (Full-face tunnel boring machine) have significant advantages in terms of fast advance rates, high support capacity, being favorable to environmental protection and low construction costs. Meanwhile some modern mines are possible target for TBM application. TBMs have been successfully used for some roadway and inclined shaft construction. Therefore, it can be foreseeable that the TBM tunnelling method will be the first choice and preferred future method for deep rock roadway construction in coal mines. However, because of the complicated construction environments, many technical challenges are encountered during TBM tunnelling in deep roadway including the presence of: (a) mixed and changing grounds; (b) high geostress; (c) squeezing deformation and the induced TBM entrapment or overstressing on supports; (d) fractured and faulted zones; (e) special requirements for TBM assembly, explosion-proof, influences of roadway or cavern groups, drainage due to the construction environments in coal mine. Therefore, in order to cope with these challenges in deep roadway tunnelling, the following scientific problems are identified as needing urgent examination: ground stress distribution and geological conditions investigation of deep roadway; interaction mechanism between the surrounding rock and the TBM; safety control for surrounding rock stability; informatization construction, optimization decision and intelligent control for TBM tunnelling. Some research progresses are also presented. Solution to these problems will provide an important theoretical foundation for application of TBMs in deep coal mines. [ABSTRACT FROM AUTHOR]

Artisanal and small-scale mining (ASM) is an important and growing economic activity throughout the Global South. ASM can provide livelihoods where few alternative economic opportunities exist, but it can also cause significant social and environmental problems, creating a need for effective regulation. State authorities have, however, struggled to control an activity that is dynamic, has few barriers to entry, and often occurs in remote areas far from national capitals. One potential regulatory tool involves allocating land to establish ‘designated areas’ for ASM in order to contain operations within discrete zones, facilitating government control, managing relations between ASM and Large Scale Mining (LSM), and mitigating its negative effects. This article explains the rationale for use of designated areas, identifies key policy issues and choices involved in creating them, and provides examples of legislation providing for their establishment. It documents the fact that such provisions are in reality rarely implemented and that, where they are, they generally fail to meet demand for ASM land and are not effectively managed. It identifies a number of proximate causes for these failures, including competition for land, overlapping and ambiguous jurisdiction between different levels of government, resource constraints facing regulators and political ambivalence towards ASM at the national level. It argues that these causes can only be addressed by realigning the governance of land so as to give local and customary authorities a much greater role in land allocation and management, and if national governments overcome their ambivalence towards ASM and accept it as a vital source of economic activity that requires effective regulation. [ABSTRACT FROM AUTHOR]

Processing and interpretation of huge array of mine seismicity data obtained in mines of Norilsk Nickel Mining and Metallurgical Company has revealed the “pulsating” mode of seismic energy release on the background of an increase in the strata pressure and, based on the information on monthly migration of reduced centers of seismic energy release within the mine fields, enabled development of a rockburst hazard criterion for individual rock mass areas. The prognostic criterion of the limiting state of a rock mass area is developed based on the ratio of kinematic characteristics of seismic events, which are the velocity of a reduced center of seismic energy release and the apparent velocity of “migration” of individual seismic events closely timed within the ranges of stress concentration zones inside the mine fields. Verification of this criterion using an ample seismic data base accumulated for a number of years in a mine of Norilsk Nickel has displayed high sensitivity of the criterion towards the change in the stress state of rock mass areas under monitoring. [ABSTRACT FROM AUTHOR]

Highwall mining involves driving a series of parallel entries with web pillars in between. These entries are driven by using a continuous miner with attached conveying system to extract locked up coal behind the highwall slope when the open cut coal mine reaches its ultimate limit. These entries are driven unmanned, unventilated and unsupported. Therefore, a detailed knowledge of structural features ahead of operations is essential in assessing the stability of these entries. Highwall mining operations can greatly benefit from accurate structural mapping of rock mass defects. The stability of these entries can be suitably assessed for any major roof failure by adopting discrete fracture network based structural modelling to characterize and delineate the regions of possible major roof failures to prevent damage to the conveyor and burial of the expensive continuous miner. In this paper, a generalized framework is described based on photogrammetric survey, digital mapping and discrete fracture network based structural modelling to characterise such failures for an Indian highwall mining operation. A sensitivity analysis is undertaken to demonstrate the significance of structure persistence in the geotechnical assessment. Such analysis would provide more insight into designing highwall mining layouts and in predicting possible impending highwall failures, and indirectly facilitates reducing machine downtime for better management of highwall mining operations. [ABSTRACT FROM AUTHOR]

Axial splitting is an important failure mechanism in rock engineering. This failure mechanism is particularly observed in the vicinity of free surfaces of rock structures. Different possibilities such as existence of defects, pores and micro-cracks in the rock specimen have been attributed as the cause of axial splitting in the literature. Based on some physical uniaxial compression tests on Pennsylvania blue sandstone, an alternative theory for axial splitting is proposed. In this theory, axial shear cracks are considered that are induced because of non-uniform deformation of the specimen ends. Dislocation along these axial shear cracks is the cause of rock lateral dilation which results in radial stresses. The radial stresses push out the cylindrical thin shells of the specimen. Consequently, radial cracks are developed which subsequently cause rock spalling in mode-I fracture. The proposed failure mechanism is discussed within the framework of a simplified theoretical model. The prediction of the model is then compared with the physical observations. In addition, a discrete element bonded particle system is utilized for rock simulation in uniaxial compression testing. The prediction of the numerical model is consistent with the physical observations. [ABSTRACT FROM AUTHOR]

Development of deposits of water-soluble minerals is connected with the risk of the accidents caused by the destruction of the waterproof stratum, and, as a consequence, water breakthrough into the mines. Thereupon, besides the problem of the mine's loss the problem of stability of the massif uppermost part appears. This part includes the foundations of buildings and serves as the base for railways and highways, bridges, dams, pipelines and etc. At the present stage of remote geophysical techniques of monitoring and prediction of such negative natural and technic origin, processes methods of high-resolution seismic survey on reflected waves have been developed most of all. In addition to prompt acquisition of physical and geological models of the section, the results of seismic observation's interpretation are proposed to be used as a part of parametric support for geomechanical calculations, which makes possible to predict rock mass stability in the range of transport facilities located above the mines. [ABSTRACT FROM AUTHOR]

The subject of this article is an estimation of the initial capacity of a gas storage cavern, depending on the thickness and the depth of a bedded salt deposit, and the cavern's capacity decrease in time due to its convergence. It was assumed that the relative rate of convergence depends on the depth, the range of the storage pressure and the cavern diameter to height ratio. The discussion will consider the shape of the cavern and the pressure range of natural gas storage. Also, potential locations in Poland for natural gas storage in bedded rock salt deposits in terms of geological and mining criteria are presented in this article. Based on Zechstein isopach maps, as well as maps of its top depth, potential storage capacity maps per unit area were developed. Presented examples will cover two potential regions i.e., bedded salt deposit in the Zatoka Gdańska region and Fore-Sudetic Monocline. These maps will be the basis for the analysis of the suitability of the bedded rock salt Zechstein deposit for natural gas storage. [ABSTRACT FROM AUTHOR]

Over the last 30 years the average grade of ore bodies has significantly decreased while the proportion of waste removal has in many cases more than doubled. This in turn has led to a major increase in energy consumption and decrease in productivity across mining operations. Metal preconcentration at coarse scale (10–100 mm) by screening has the potential to reverse decreasing mining productivity trends through early rejection of uneconomic grade material prior to energy intensive comminution. Metal preconcentration of feed grades using screening exploits the propensity of certain ores to preferentially deport metal into specific size fractions during breakage. This phenomenon is referred as preferential grade by size deportment. The exploitation of preferential grade by size response involves generation of multiple streams with different metal content post screening. Streams can be engineered for different grade characteristics suitable for different processing destination (eg: as waste, leach, and mill). Preferential grade by size data obtained by an extensive belt cut sampling campaign after primary crushing has been used to develop a method to define samples that are amenable for metal preconcentration by size. This amenability changes depending on cut-off grade, magnitude of preferential grade by size response and the proportion of mass contained in individual screen products. Outcomes of this work will support the short term preferential grade by size operational implementation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Conceptual model of abandoned underground mine is introduced. • Abandoned underground mine is vulnerable and fragile with time-limited stability. • Its environment is azonal and fast evolving. • Abandoned underground mine is an important semi-natural ecosystem. We have investigated a typical abandoned underground slate mine situated in the Bohemian Massif (Central Europe) in order to describe its elementary components and to outline the varied relations among them. Based on the results from geological, geomorphological, hydrological, microclimatic, and biological investigation, we have defined the abandoned underground mine as an important but overlooked semi-natural ecosystem that represents an azonal and relatively fast evolving environment. Unlike any other studies published so far, we have found it also vulnerable in terms of fragility and time-limited stability. Our results together with a comprehensive discussion highlight the fundamental features of the abandoned underground mine and finally serve as a basis on which we introduce a conceptual model of the abandoned underground mine. The complex and interdisciplinary perception of abandoned underground mines is crucial for appropriate environmental assessment, tourist management, natural protection or remediation. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.eeh.2008.05.001 Byline: Thorsten Lubbers Keywords: Economic history; Event study; Germany pre-1913; Mergers and acquisitions Abstract: We investigate the wealth effects of takeovers in the mining industry of the German Ruhr district between 1896 and 1913. We employ event study methodology and use a new data set that covers stock prices of joint-stock mining companies and information on share prices of Gewerkschaften, an organisational form that was exclusively designed for German mining companies. Our empirical results show that takeovers enhanced shareholder value. The clear beneficiaries were the owners of the acquired companies, those of the acquirers hardly gained significantly. Collusion in the mining industry benefited the shareholders of small, poorly performing takeover targets. Author Affiliation: Max Planck Institute for Research on Collective Goods, Kurt-Schumacher-Str. 10, 53113 Bonn, Germany Article History: Received 7 August 2007 Article Note: (footnote) [star] We would like to thank Thomas Bittner, Carsten Burhop, Markus Lampe, Ulrich Pfister, and an anonymous referee for helpful comments and suggestions. All remaining errors are the sole responsibility of the authors. In addition, we would like to thank our student assistants Nina Buge and Peter Monke for substantial support in collecting the data for this article. Financial support of the Fritz-Thyssen-Stiftung (Grant No. 10.03.1.044/Industrieokonomische Analyse des Rheinisch-Westfalischen Kohlensyndikats 1893-1913) is gratefully acknowledged.

Abstract: In this paper, the capability of determining the three dimensional (3D) ground displacements due to underground mining using the multiple ALOS PALSAR interferometric pairs acquired with different viewing geometries has been investigated and validated in the area of West Cliff colliery, New South Wales (NSW), Australia. Four ALOS PALSAR interferometric pairs acquired with two different incidence angles from both ascending and descending orbits were used in this study. Three different approaches were used to derive the 3D displacement maps. The first two approaches utilised SAR data only, while the third approach required a one dimensional measurement by using other surveying techniques as inputs. The results were compared with the GPS field survey data obtained between April and May 2008. The obtained results and the GPS data agreed well with each other in the vertical and the east–west directions. However, the precision of displacement measured in the north–south direction was much poorer for the first two approaches compared to the third approach. This was due to two reasons: (1) the lack of viewing geometries, and (2) the poor temporal overlap in the interferometric combination datasets. The results suggested that it is possible to use other one dimensional surveying techniques to assist the InSAR measurements in order to enhance the accuracy of the 3D deformation derived. The horizontal movements in transverse and longitudinal directions were calculated from the 3D deformation results, in order to derive the subsidence parameters that have been caused by mining activities. The subsidence parameters derived matched well with the GPS-derived parameters. The results suggested that an accurate 3D displacement vectors can be derived by combining InSAR-measurement with measurement from other equipment such as extensometer and optical fibre which may carry out measurement in one direction only (ideally north–south direction). [Copyright &y& Elsevier]

Abstract: The dissolution of soluble minerals may influence the mechanical properties of soils used in earth structures or foundations and may compromise the safety of such structures. This study focuses on changes in the physical properties of soluble mixtures (salt–sand mixtures) during dissolution. Experimental and numerical studies are performed to monitor the behavior of particulate materials during the dissolution process in soluble mixture. Experimental results show that during salt dissolution the shear wave velocity decreases, and subsequently increases to a stable value. Dissolution initiated from the bottom plate causes shear wave velocities to increase slightly in the upper layer, as a result of fabric changes, arching (force chain) generation, and horizontal stress locking. Numerical results show that the mixture fabric changes to a more anisotropically packed state, and becomes more unstable, due to the dissolution. The experimental and numerical results provide valuable insights into the micro-behaviors of soluble mixtures. [Copyright &y& Elsevier]

Abstract: Underground coal fires pose a threat to the environment and the health of those living in their proximity and can result in economic losses if these fires occur at mining areas. Design of methods to extinguish these fires requires that the extent of the subsurface fire be delineated. A conceptual picture of the workings of a subsurface coal fire near Durango, CO is presented first, which shows how the overburden above the burning coal seam can become heated. In high temperature and low O2 conditions, the heating of the overburden leads to the formation of magnetite, and its presence and the alignment of magnetic moments can be detected by a magnetometer. Magnetometer surveys allow high resolution areal mapping that differentiates among previously burned, currently burning, and unburned coal seam areas. The current and previous locations of the subsurface fire regions that are delineated by the magnetometer survey conducted at a fire on the Southern Ute Indian Reservation are consistent with various supporting data such as gas composition, temperature, and snowmelt data. [Copyright &y& Elsevier]

Abstract: Increasing usage of cemented paste backfill (CPB) in underground mines combined with the fact that every single mine or backfill structure is unique with regards to their temperature conditions require a need to clarify and quantify the effect of curing temperature on the mechanical properties of CPB. Hence, the main objective of this study is to use an experimental approach to study the influence of curing temperature and combined effect of temperature and CPB components on the main mechanical properties (strength, modulus of elasticity, and stress–strain behaviour) of CPB. Thus, different types of CPB specimens are tested at different curing times and temperatures (2°C, 20°C, 35°C, and 50°C). The compressive and split tensile strength, modulus of elasticity, stress–strain behaviour and microstructure are evaluated by laboratory tests. The results show that the curing temperature has a significant influence on the mechanical properties of CPB. Moreover, the effect of temperature on these properties depends on the binder type, W/C ratio, tailings type and curing time. The study demonstrates that the mine and backfill temperatures are an important parameter that should be considered in mine backfill operations. [ABSTRACT FROM AUTHOR]

Abstract: Underground coal and copper ore exploitation in two Polish mining regions causes mining tremors and a series of other negative phenomena in the environment. Although these tremors are strictly connected with human activity, they differ considerably from other paraseismic vibrations. The moment of their occurrence is not to be foreseen likewise for earthquakes. The main problem discussed in the paper was formulated as the neural network evaluation of a relation between mining tremor energies, epicentral distances and acceleration response spectra. Back-propagation neural networks with Resilient back-propagation learning method were used. Each input vector included information about the mining tremor energy and the epicentral distance. Values of acceleration response spectrum were expected as the outputs of neural networks. Neurally evaluated spectra were compared with spectra computed on the basis of experimental data. After the network is trained and tested, it can be used for mapping of new data of mining tremor energies and epicentral distances into the spectra. Then, what is the substantial advantage of neural approach, the prediction of acceleration response spectra can be performed without recording of surface vibrations. In the light of the results, it is visible that the presented way of computation of acceleration response spectra can be peculiarly applied to prognosis of mining tremors influences on structures. [Copyright &y& Elsevier]

The Middle Pennsylvanian Herrin and Springfield coals contain the majority of the Illinois basin's resources. Many mining issues of these two seams are directly related to the geology of the region, including regional stress, faulting, and facies changes. Some of these conditions are widespread, while others are locally restricted. The long history of mining in these seams has been associated with many difficulties and hard-learned lessons related to mining geology especially concerning aspects of coal quality and roof geology along paleochannels, moisture-sensitivity in shales, fractures and "slips" in shales, floor heave, lateral stresses, clay dikes (veins), and coal balls. Both seams occur within classic "cyclothems," resulting from sequences of deposition between lowstand and highstand deposition. Transgressive, marine black shales and limestones blanket the coals across much of the basin, except near syndepositional channels where wedges of gray silty shale and interbedded shale and sandstone intervene between the coal and transgressive shale. Differences in the thickness, chemistry and strength of various shales in each sequence influence coal quality and roof conditions in underground mines. Associations of mining geology issues not specifically related to tectonics and horizontal stress, are (1) syndepositional channel and channel margin conditions, (2) post-depositional channels, (3) gray-shale wedge margins, and (4) marine shale roofs; especially where limestones thicken. Many of these features are similar to both seams, while others are more common in the Herrin, than Springfield Coal. Similar conditions occur above other coal beds in the Illinois Basin, as well as coal-bearing strata in other basins. Herein we review horizontal stress, fractures, coal quality, partings, coal balls, clay dikes (veins), dips and swales, floor heave, moisture sensitivity in shales, shale rolls, limestone bosses and cutouts, paleochannels and cutouts, stackrock conditions, paleoslumps, coal riders, kettlebottoms, and concretions in the roof. Hopefully, this summary will be useful for understanding seams with similar geology, but with less research on mining geology or shorter mining histories. • This paper reviews geologic factors which influence the mining geology of the Springfield and Herrin coals in the Illinois Basin. The long history of mining in these two seams has provided a wealth of data for understanding a variety of factors including lateral stress, faulting, floor heave, moisture-sensitivity in shales, paleochannels, channel margins, stackrock conditions, clay veins, kettlebottoms (in situ tree stumps), and paleoslumps. [ABSTRACT FROM AUTHOR]