IAEG/AEG Annual Meeting Proceedings, San Francisco, California, 2018 - Volume 3

Mine-induced landslide hazard in Polish opencast mines and spoil dumps are a common phenomena. It is caused by a high depth of exploitation, low strength parameters of clayey soils on the slopes and geological or groundwater triggers. In this paper chosen examples of landslides occurring in the largest Polish lignite opencast mines together with implemented investigation and remedial measures are presented. These included the latest monitoring results obtained inside EU Euracoal SLOPES project “Smarter Lignite Open Pit Engineering Solutions” conducted by six European partners. The Polish part of the investigation in this project was performed in the largest lignite opencast excavation in Europe, with a length of 13 km and a width of 3 km. Belchatow mine with a depth of 310 m is affected by numerous landslides with volumes of few thousand to 3.5 million m³. Geotechnical investigations carried out for the SLOPES project on the western slope of the mine included 100 m depth on-line shape accelerated inclinometer and pore pressure transducer at 30 m depth. The obtained data should allow for better risk management and were implemented in numerical modeling of instability associated with the pit slope.

The studies performed at the Sergeev Institute of Environmental Geoscience RAS (IEG RAS) in the territory of VerkhneKamskoe potassium salt deposits in the Perm region of the Russian Federation are aimed at the assessment of geological conditions and the forecast of geohazard occurrence within the undermined areas of potassium mines in Solikmask-Berezniki urban and industrial agglomeration (SBUIA). The work mainly involves engineering geological interpretation of the available data on geological and engineering survey, complex monitoring, as well as numerical simulation of geoenvironment for investigating groundwater filtration and the data on the transformation of the stress-strain state of rock massifs. The results obtained are important for minimizing risks of accidents at the operating mining facilities.

The presence of dolerite intrusions in underground collieries often causes damage to mining equipment, delays in mining schedules and loss in production. This is often exacerbated by inadequate pull from the blasting operations along the intrusion. Thus, the proficient removal of dolerite intrusions through efficient blasting techniques play a vital role in the economic output of a colliery. This study is focused on one such intrusion within the Magdalena Colliery, wherein a 13.88 m dolerite dyke resulted in the replacement and displacement of the Alfred seam. Selected sampling was conducted along the length of the intrusion in order to determine the petrographic and geotechnical properties influencing the blasting performance of the dyke. A detailed petrographic analysis was done by analyzing thin sections of the dolerite in order to identify the major minerals present. X-ray diffraction (XRD) analysis was also conducted to determine the percentage composition of minerals along the intrusion. Geotechnical tests were also conducted in order to assess the technical properties of the dolerite. The geotechnical tests conducted included point load test, sound velocity test, uniaxial compressive strength test and Brazilian disc strength test. The study conducted demonstrates that a strong correlation exists between the blasting performance and geotechnical and petrographic properties of the dyke.

Reactive materials have been used as a solution to prevent potentially toxic metal contamination stemming from mining waste disposal. These materials are characterized by a high cation exchange capacity (CEC) and a predominance of negative charges, favoring their potential utilization in metal cation immobilization. Therefore, the aim of this study is to compare the sorption capacity of common metals in mining areas (Pb, Zn and Cd) with zeolite, an inorganic material traditionally studied and used for this purpose, and compost, a low-cost organic material, that in comparison to zeolite, has been sparsely researched. Two Cuban commercial clinoptilolite zeolites were evaluated: natural zeolite (NZ) and NaCl treated zeolite (TZ). Two municipal solid waste-derived composts were also assessed with differences in the composting method: windrow (WC) and static pile (SPC). Batch equilibrium experiments showed that the selectivity of removal of TZ, WC and SPC followed the order Pb > Cd > Zn. The only exception was NZ (Pb > Zn > Cd). In general, all materials presented higher performances than Pb (with adsorption efficiency more than 95%). The SPC was revealed to be the best adsorbent of Pb, but with a similar removal percentage for the TZ. The TZ was significantly more efficient in retaining Zn. In the case of the Cd, the WC and TZ showed the highest removal percentage. These results suggest that compost, a low-cost byproduct, can adsorb a considerable concentrations of metals, and thus is able to compete with zeolites for use, isolated or combined with other materials, as an effective sorbent in metal contamination.

Sequential extraction methods (SEM) have been developed to study potentially toxic metal (PTM) fractionation in soil. Although many procedures have been suggested in literature, these methods are usually developed for temperate soils. Thus, the objective of this study was to compare a SEM developed for temperate soils with a SEM developed for tropical soils. The soil samples chosen for this comparison were collected in a former deposit of slag enriched in lead (Pb) and zinc (Zn), located in Adrianópolis (Brazil—tropical soil). These samples were collected in profile to verify metal mobility in depth. Since it is known that soil characteristics affect metal mobility, the soil pH, the soil organic matter content (SOM), the cation exchange capacity (CEC) and the pseudo-total concentration of Pb and Zn were determined. Zn and Pb were predominantly associated with Fe–Mn oxides and the residual fraction. Using methodology developed for tropical soils, it was possible to distinguish Fe–Mn oxides and verify that Pb and Zn were mainly associated with the less mobile form (crystalline Fe oxides). Metal associated with the mobile fraction varied significantly, being more abundant when using the temperate soil method. It is concluded that the procedure for tropical soils is more adequate for distinguishing different forms of Fe–Mn oxides in soil, but the temperate soils procedure was more effective in extracting exchangeable and organic matter fractions.

This paper presents a case study of the grouting improvement of high-rise buildings built over an abandoned coal mine where several seams were mined out. The engineering behavior of the subsided land and its stability before and after grouting plays an important role in its use for construction and ecological development. The stability, suitability, and grouting efficiency for a case study of the Hupan Buildings built over an abandoned mined-out area in Xuzhou, Jiangsu, China were investigated through an in situ investigation and a theoretical analysis. Grouts with water-solid ratios of 1:1 and 1:1.5 were injected into the abandoned mined-out panels through 185 boreholes. The study area can be divided into three zones with different stability and suitability. Four detection boreholes were drilled for evaluating the grouting efficiency. The results show that the stability of the mined-out area was improved by grouting. The study provides a good basis for the construction and ecological use of subsided land.

In the present work, an Advanced Differential Interferometric Synthetic Aperture Radar (DInSAR) technique has been used to measure deformations related to Seruci-Nuraxi Figus underground coal mine, located in the Carbonia-Iglesias mining district (Sardinia region, Italy). Specifically, COSMO-Skymed (CSK) data, obtained in the framework of the Third Not-ordinary Plan of Environmental Remote Sensing project by PSP-IFSAR technique, have been used to analyze the deformations occurring between 2011 and 2014 in the study area to improve the phenomenon knowledge. Availability of images acquired in ascending and descending geometries has permitted to calculate the vertical displacement component. Accordingly, a maximum subsidence of about 25 cm has been measured in the time span 2011–2014. Furthermore, time-lapsed vertical deformation profiles have also been carried out to analyze the dynamic ground-deformation development. DInSAR measurements have allowed obtaining information on the spatial and temporal development of a phenomenon, very useful to the cause-effect mechanism understanding aimed to improve the resources management.

Field monitoring sensors and an instrumentation system were installed in a mine waste dump slope at the Imgi mine in South Korea to investigate and analyze the surficial seepage and unsaturated soil behavior at the vadose zone. The field instrumentation consisted of a data acquisition system, a solar charging system, and measuring sensors. The rainfall, matric suction, and volumetric water contents were continuously measured from the units in the site and analyzed with the soil water characteristic curve (SWCC) estimated from laboratory experiments. The variations in matric suction and volumetric water content were primarily affected by the rainfall intensity. At the surface of the waste dump slope, the largest increase and decrease in the changes of matric suction and volumetric water content were observed during the wetting and drying processes, respectively. The measured matric suction and volumetric water content data from the field monitoring site were compared with the SWCCs obtained from the laboratory test, and the measured data was located between the drying and wetting paths. The drying and wetting paths obtained from the laboratory test are regarded as the primary drying and wetting curves, respectively. Therefore, the measured data with a nonlinear relationship between matric suction and volumetric water content could be defined as scanning curves, which are located near the primary drying and wetting curves. In particular, the characteristics of unsaturated soil near ground surface were dominantly associated with the primary wetting curve.

Petrographic characterization showing mineralogical, textural and structural aspects of rocks is an essential technique in the study of the performance of concrete aggregates, specifically on the investigation of the alkali-aggregate reaction (AAR). The assessment of this deleterious reaction, considered as one of the most important pathologies, is a required test in the waste utilization programs. In this paper, waste rock samples of a feldspar mine were studied by optical microscopy, approaching aspects related to morphology, texture and alteration degree to determine the potential alkali reactivity for use as aggregates in cementitious mixtures. The rock studied shows characteristics that make it susceptible to be a reactive aggregate, due to, mainly, the strained quartz and the microcrystalline quartz. However, these results must be confirmed by standard mechanical test methods.

Hong Kong is often described as a ‘concrete jungle’ and aggregate sourced from local hard rock quarries has formed an essential construction material for the development of the cityscape seen today. However, the continual expansion of the urban area coupled with increasing environmental controls and awareness means that most of the local quarry sites providing aggregate to the construction sector have been closed down and rehabilitated over the last 20 years and, despite an abundance of hard igneous rock suitable for aggregate generation, no new local quarries have been established in almost 50 years. The decline of aggregate supply from local sources arising from this has resulted in an increased reliance on imported materials, with associated implications in terms of supply, cost and quality control as well as a reduced ability to sustainably process good quality rock generated by construction projects. With these concerns in mind the HKSAR Government initiated a review of short and long-term aggregate supply strategies for Hong Kong, including territory-wide searches for potential aggregate reserves, both surface and underground, that took due account of the associated technical, environmental and socio-political aspects affecting reserve accessibility and extraction potential. This paper explores some of the key factors associated with the past, present and future supply of aggregate in Hong Kong and outlines some of the ways in which the future of quarrying might be considered for the territory.

Turkey is a bridge between Europe and Asia. There are numerous historical monuments in Turkey that were built by using natural stones. Due to the geographical features of Turkey, natural stones were exposed to different climatic conditions over time. Temperature and humidity changes have affected physical and mechanical properties of natural stones. The aim of this study is to investigate the physical and mechanical properties of basalt, marble and limestone, which are frequently used in historical buildings in Turkey, in saturated and dry state at different temperatures. For this purpose, basalt, marble and limestone samples were collected from their today’s quarries. The obtained samples were dried and saturated with water, cooled to −15 °C and heated to 105 °C. In every 5 min temperature values of samples were measured to reach up to room temperature (about 23 °C), thus their CERCHAR abrasiveness index were determined. According to the results obtained CERCHAR abrasiveness index increased when the temperature value exceeded 40 °C. In water saturated samples CERCHAR abrasiveness index didn’t change when the temperature value exceeded 30 °C.

In addition to the increasing population and structuring in the growth/development process of a country or megacity, the obligation to maintain industrial and infrastructure investments makes aggregate (crushed stone, etc.) one of the most consumed building materials per capita. Crushed stone, cement and ready-mixed concrete are the basic building blocks of the construction sector and have a great contribution to the development of the industry as well as the increase in national income and employment. However, work safety, environmental problems and increased social opposition to aggregate (crushed stone) open pit mines is intensive and unplanned/irregular urbanization areas are hampering the future sustainable production of medium and large sized enterprises in technical, environmental and economic aspects. The city of İstanbul which has a high aggregate production (90 million tone/year) provides a good example of those issues. In order to maintain efficient and sustainable aggregate resources in İstanbul and its surrounding region, plan and program should be reviewed and new strategies evaluated to facilitate the sustainable management of resources. In this regard, the importance of existing resources and their possibilities, determining operable new resources and their management have been considered.

The durability of concrete can be affected due to internal reactions between the alkalis of the cement paste and certain forms of silica present in the aggregates. Petrographic examination provides a useful tool to assess the alkali reactivity of aggregates. In the present work Hungarian stones that are used as aggregates were analyzed for alkali reactivity. Sandstone, two granitic rocks, one andesite and one diabase were studied using petrographic microscopy in order to identify the presence of potentially reactive forms of silica and to classify these rocks accordingly. Complementary methods such as scanning electron microscopy were also applied. Our results confirm that all studied rocks, except diabase, contain silica that has a potential of alkali reaction. Hence analyzed rocks are classified to Class II from the alkali reactivity point of view, while diabase is in Class I.

Aggregate tests are used worldwide to assess the durability of crushed stone. These standardized test methods aim to determine the resistance to wear by using given rotations as it is described in the European Norm of Micro-Deval test (EN 1097-1:2012). It recommends 12,000 rotations to determine the Micro-Deval coefficient of a rock. The present paper goes a step further since it aims to describe the long-term wear resistance of tested volcanic rocks (Nógrádkövesd, Hungary). Micro-Deval coefficients were determined after gradual increase of rotations from the suggested 12,000–780,000. The material loss was recorded in 65 steps, i.e., after each increment of 12,000 rotations. Not only the material loss but also grain shapes were documented. As it was expected the grains became smaller and more subspherical with the increasing number of rotations. Regression analyses were used to describe the material loss. Correlation between the number of rotations and the Micro-Deval coefficients were also outlined. Pearson coefficient of correlation was also calculated. Our test results suggest that during the long-term Micro-Deval tests the aggregate durability properties change due to long-term wear. The regression analyses of the results give a strong indication that polynomial and exponential curves are suitable to describe the changes in Micro-Deval coefficients on a long-term wear. These tests also demonstrate that it is possible to predict the long-term behaviour/wear of andesite under investigation by using the applied equations.

Rocks and groundwater of karst areas are weakly protected from any pollution. The most common pollutants within them are oil hydrocarbons. Microbial populations of karst rocks and groundwater are able to degrade a large number of contaminants under the existing redox conditions, often used in biotechnological methods of remediation. The authors investigated oil polluted karst territories of the Perm region (Russian Federation) to develop methods of remediation. Two sites of karst rocks and groundwater with different redox conditions and impacted by oil and oil-products were studied. Aerobic hydrocarbon-oxidizing bacterial processes occured in the first site, and this paper describes the complex method of mechanical and microbiological cleaning to achieve complete oil removal. Anaerobic degradation of oil hydrocarbons during sulfate reduction process was detected in the second place. One of the products of this process, hydrogen sulfide, is very toxic to water fauna but readily oxidative in air. The authors recommend constructing special oxidizing and precipitating ponds to improve the environment.

This article deals with two aspects of increased karst risk, at the border of Europe and Asia, caused by the processes of leaching and dissolution of rocks. Their activation and occurrence enhance under man-made conditions, including in areas of mining. Territories refer to the first group in limits karst rocks, where technical activization of a karst is created by the following technical factors: chemical, geodynamic, mechanical and hydrodynamic. The territories of the second group are not associated with natural karst rocks. Here, the processes of dissolution and leaching of rocks occur outside the zone of development of karst rocks in various subsurface and surface cavities flooded with groundwater in the post-operational period of mining production. Similarly to karst massifs, under certain conditions, an outflow of mine waters is formed from flooded mine workings, similar to karst siphon springs, with increased salinity, and other parameters. The activity of destruction and offset mineral components exceed natural conditions by 1–2 order, according to the analysis of leachings with sulphuric acid.

On the Swabian Alb high plain, new line Wendlingen–Ulm, southwestern Germany, 2D electrical resistivity tomography (ERT) measurements were performed during construction at the excavation bottom level in addition to the standard investigation program (including microgravimetric and seismic methods) to test the effectiveness of an inverse Wenner-Schlumberger array for exploring geological defective karst voids and other karstic features in a highly heterogeneous karstic environment. The 2D ERT survey (ABEM Terrameter SAS 4000, inverse Wenner-Schlumberger array, 2.0 m electrode spacing, roll-along technique, robust inversion, RMS error: 1.61% for a maximum of 5 iterations) provided a high-resolution image of the subsurface, revealed the size, shape and spatial distribution of conductive clayey/loamy deposits (<60 Ωm) and delineated them from an intensely fractured and/or highly weathered limestone bedrock (60–240 Ωm), respectively. In addition, the 2D ERT profile indicated several resistive zones of moderately fractured and/or medium weathered limestone bedrock (240–960 Ωm) as well as the general absence of intact limestone bedrock (>1000 Ωm) and air-filled voids (>2000 Ωm). These observations were confirmed by extensive direct probing investigations (1 exploration drilling, 4 core drillings, 19 destructive drillings, 2 trial pits). Moreover, the 2D ERT data coincided with the microgravimetric and seismic results of the previously conducted standard investigation program to a high degree. The exact spatial distribution with depth as well as the internal structure of the detected anomalies (clayey/loamy deposits, moderately fractured and/or medium weathered limestone bedrock) could, however, only be obtained from the 2D ERT data. The 2D ERT measurements conducted with an inverse Wenner-Schlumberger array provided a decisive contribution to karst reconnaissance in a highly heterogeneous karstic environment like the Swabian Alb high plain, on the new line Wendlingen–Ulm.

The karst rocky desertification is one of the major bottlenecks for the eco-environmental safety and economical sustainable development in karst areas of China. The formation of rocky desertification is influenced by many factors, and the lithology of carbonate rocks has the most profound influence on it as internal factors. The lithological difference of carbonate rocks determines its weathering process and the way of the accumulation and loss of surface soil, which makes the origin, temporal and spatial evolution rule and governance difficulty of rocky desertification different. In this paper, the limestone and dolomite in the moderate and severe rocky desertification region in the Guizhou plateau are selected as the research objects. Stress-dissolution experiments of carbonate rocks are carried out by the simulating open system of the water environment of epikarst zone. The differences in deformation and dissolution characteristics of limestone and dolomite under different stress conditions are analyzed. In addition, the characteristics of surface and internal pore structure of the rocks are analyzed from the microscopic view. The results further explain why the degree of rocky desertification in the dolomite area is lighter than the limestone area, but it is more difficult to control than the limestone area. These results provide a theoretical reference for the controlling of rocky desertification.