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It is well known that some sinkholes or subsidence takes place from time to time in areas where abandoned room-and-pillar-type mines exist. The authors have been involved in studies on the stability of abandoned mines beneath urbanised residential areas in the Tokai region, Japan, and there is a great concern about the stability of these abandoned mines during large earthquakes as well as in the long term. The 2003 Miyagi Hokubu and 2011 Great East Japan earthquakes caused great damage to abandoned mines and resulted in many collapses. Therefore, there is great concern about the stability of abandoned lignite mines in the Tokai region, particularly in Mitake Town, as the region could be affected by the anticipated successive Nankai, Tonankai and Tokai earthquake with a magnitude of 9.0. The authors give a brief summary of the geology of the Tokai region, the short-term and long-term properties of rocks surrounding the abandoned mines and their degradation characteristics. Then, some sinkhole and subsidence problems in the town due to long-term loading in abandoned lignite mines as well as earthquakes are described. The local and global stability issues of abandoned mines are described, and some procedures for estimating their stability in the long term are presented. Some discussions are made on the effect of depth and groundwater on the formation of sinkholes or ground subsidence associated with abandoned room-and-pillar lignite mines.

In this paper, a geological–geotechnical rock slope classification system is presented, providing a central instrument of the safety strategy of the Austrian Federal Railways (OBB) Infrastruktur AG in rockfall protection. The classification, which is based on an evaluation matrix, enables the rock slope maintenance or inspection interval to be adapted to the geological and geomorphological characteristics of the respective rock slope. The aim is to achieve a reduction of the scope of work by adapting the inspection intervals to the expected rockfall activity. This prioritisation can be used to determine the annual cost-intensive rock scaling to be carried out on a 1- to 3-year interval. Although this semiquantitative method was especially developed for assessing rockfall hazards on rock slopes above rail lines, it could also be applied to other transport infrastructures.

Global warming, which has been observed in the world and Ukraine in particular in recent decades, may lead to a decrease in surface and groundwater. In addition, the high level of groundwater pollution and the policy of water purification is a matter of concern. Thus, the question of finding additional and alternative sources of drinking water today is highly urgent. A significant percentage of prospecting works of the last century was devoted to discovering the groundwater fields in fractured crystalline rocks of the Ukrainian Shield. As a rule, the productivity of wells of these formations did not have high flow rates, so even now, mostly the aquifers in sedimentary deposits have been exploited. The low productivity of most wells in water-bearing fractured rocks is associated with the unknown degree of fracturing of the crystalline massif: it is difficult to determine the pathways of groundwater inflow into the fracture system and, accordingly, it is not easy to justify the exploitable groundwater reserves. In this paper, using the groundwater flow model of the Zhashkiv groundwater deposit, it is considered an increase of the productivity of water intake wells in the water-bearing crystalline rocks due to the increasing degree of their fracturing by an explosion. Thus, in hydrogeology, this technique is known when trying to increase the permeability in the near-borehole space, but as a method of artificial recharge of aquiferous crystalline rocks is used very rarely. The paper also examines typical water intakes conditions in fractured crystalline water-bearing rocks, which can be recommended for increasing their productivity by the blasting method. The results indicate that an artificial increase in fracturing degree can have a significant effect on increasing the productivity of water intakes. The basic methods of using explosives, as an example of an artificial increase in fracturing degree, in solving hydrogeological problems and the mechanisms of fractures’ formation during the action of blasting are considered.

In the mining process of a coal seam containing a fault structure, due to the influence of mining stress, the rock mass inside the fault zone and between the fault and the coal pillar that is preserved to prevent fault activation is prone to producing damage and activation. This study is focused on this problem. Based on the analysis of the failure, activation and movement of the rock mass in front of the fault body and the coal wall, extended finite element numerical simulation software is adopted to study the stress evolution and deformation failure rules of a coal seam containing a fault floor. In particular, the dynamic response process (including slip velocity, slip distance and friction force) of the fault structure under mining conditions is monitored, and then the turning and failure process of the fault structure is analysed. However, an analogue modelling is reformed. A similar material analysis model is established to monitor the displacement field changes near the fault during the mining process, obtain the movement rules of the fault zone and surrounding rock mass during the mining process, and then verify the reliability of the numerical simulation results. The research results can provide references for exploring the coupling movement rules between the fault and the work area for production in the mining process of coal seam stopes, as well as prevention before water inrush under the influence of the fault and treatment after water inrush.

Актуальность. В настоящее время более 75 % проводимых подземных горных выработок поддерживаются при помощи анкерного крепления. В процессе длительной эксплуатации выработок возникают деформации приконтурного массива пород и элементов крепи. Актуальной научно-практической задачей представляется выявление типовых форм деформаций пород и элементов крепи с целью разработки проектных решений и обоснования параметров крепи при производстве текущего ремонта или восстановления подземных выработок. Цель: разработка проектных решений и обоснование параметров анкерного крепления при ремонте и восстановлении подземных горных выработок. Методы: натурные исследования, статистическая обработка результатов экспериментальных исследований. Результаты. Приведено описание, причины возникновения и формы проявления геомеханических процессов в приконтурном углепородном массиве горных выработок, закрепленных анкерной крепью. На основе длительных натурных наблюдений установлено шесть форм типовых деформаций приконтурного массива. Процесс сводообразования в кровле выработок начинается с разуплотнения приконутрного слоя, которое служит причиной расслоения пород под действием гравитационных сил, а также образования полостей. Отжим угля из боков выработок и вывалы угля происходят в связи с образованием вокруг выработки зон неупругих деформаций, где уголь и породы находятся в несвязанном состоянии и удерживаются в равновесии за счёт сил трения и отпора крепи. Ширина зоны неупругих деформаций зависит от многих факторов. Существенное влияние оказывают ширина выработки и угол внутреннего трения. При увеличении ширины выработки увеличивается коэффициент концентрации напряжений в боках. Разработаны проектные решения по усилению крепления или полной перекрепке поврежденных участков горных выработок при геомеханических процессах локального вывалообразования. Они включают в себя: схему установки, обоснование параметров и номенклатуру применяемых элементов крепи-усиления, технологию работ, список применяемого оборудования. Relevance. More than 75 % of underground mine workings are supported by anchorage nowadays. In the case of long-term mine workings maintenance the deformations of surrounding rock massif and anchoring elements occur. The surrounding rock massif typical forms deformations determination in order to develop the design solutions and substantiate anchorage parameters is currently urgent scientific and practical task. Especially it is important in case of mine workings support repair or recovery stages. The main aim is mine working anchorage design solutions and parameters substantiate during the repair and recovery stages. Methods: field measurements, statistical processing of results. Results. The paper introduces the description, causes of occurrence and manifestation forms of geomechanical processes in surrounding rock massif supported by anchorage. Based on the long-term field measurements six forms of rock massif typical deformations have been established. The roof bridging begins with decompaction of rocks, which causes rocks stratification under the influence of gravity. This results in cavities formation and lower layers separation from upper ones. Because of formation of the plastic deformation zone around mine workings the extraction and dumping coal from walls occur. Coal and rocks are in an unbound state and are kept in balance due to the forces of friction and resistance of the support in the zones of plastic deformations. Its width depends on many factors such as the working width and the internal friction angle. The coefficient of stress concentration in the walls rises up due to growth of mine working widht.

Керамика является важнейшим компонентом майкопской культуры и уникальным источником информации о ее производителях и пользователях. Целью нашего исследования является описание технологических систем, в рамках которых была произведена керамика Серегинского поселения. В статье представлены результаты технологического анализа керамического ансамбля, включающего в себя исследование методов конструирования, обработки поверхностей и обжига, а также анализ материалов, использованных для производства керамики и местного потенциального сырья для керамического производства. Жители Серегинского поселения пользовались керамикой, произведенной в рамках 2 индустрий, характеризуемых специфическими техниками, формовочными массами и принципами организации труда. Индустрии, описанные в статье, можно связать с двумя традициями, действующими в соответствии с разными технологическими принципами. Pottery is a key component of the Maykop cultural phenomenon and a unique source of information on its producers and users. The aim of this study is to describe technological systems used to produce ceramics at the Sereginskoye settlement. The article presents the results of the technological analysis of the pottery assemblage. The systematic analysis includes the investigation of vessel shaping, surface treatment and firing, as well as the study of raw materials used to produce ceramics and local potential resources for ceramic production. The Sereginskoye inhabitants used pottery produced by three industries characterized by specific techniques, clay fabrics and principles of production organization. The industries described in the article can be associated with two traditions based on different technological principles.

This work presents a geological-geotechnical risk map of gravitational mass movements and a susceptibility map to shallow translational slides to Vila Nova community, located in the municipality of Colombo, Brazil. The first map was created through a qualitative mapping methodology and the second one was elaborated using a deterministic method of slope stability. An aerial photogrammetric survey with UAV technology was performed, as well as field reconnaissance, laboratory testing, and geoprocessing techniques. Seven slope failures were identified as well as a range of other evidences of instability associated with the predisposition of the terrain to erosive and gravitational movements linked to human intervention without urban planning and engineering techniques. Moreover, the qualitative and quantitative analyses pointed out that 13% to 9% of the study area, respectively, are in a very high-risk condition for landslides. Thus, the resulting cartographic products are presented as an important technical contribution for landslide risk management as well as land use planning for reducing the geotechnical problems faced on site.

The development of hydrogeology with respect to hard-rock and fractured-rock aquifers is described. The differences between porous aquifers and karst are explained, as well as the groundwater flow regimes in the different fractured rocks. A position is taken on numerical modeling, from the beginning of modeling to the present day, with focus on particular challenges. Because of the importance of fractured-rock aquifers, the tools for groundwater exploration and future resource management are mentioned. The essay introduces a topical collection of articles.

Thin layer placement (TLP) is the purposeful placement of thin layers of sediment in an environmentally acceptable manner to achieve a target elevation or thickness. TLP is used for a variety of purposes, such as sediment management, beneficial use of dredged material (DM), and ecological enhancement. The term “thin” is used to distinguish TLP from other methods of sediment placement in which sediments are applied in layers on the order of several meters thick. In this paper, DM disposal refers to the deposition of sediment in a location and manner where no beneficial use is attained; with DM placement the sediment is used to benefit society and the environment. The application of thin layers of sediment has advantages over more traditional, thicker sediment applications in environments where these thicker layers pose potential challenges to natural resources, infrastructure, navigation, or other assets. Although TLP projects are most often conducted in wetlands, there are open-water applications as well. But because TLP is relatively early in its development, there is a dearth of design and construction information and guidance available to practitioners. This paper provides a high-level summary of pending national TLP guidance being developed by the authors on behalf of the U.S. Army Corps of Engineers’ Engineer Research and Development Center (USACE ERDC).

The identification of open-pit mine water sources is of great significance in preventing water disasters. Combined with hydrochemistry and multivariate statistical analysis, this paper systematically analyzed the hydraulic connections between aquifers and the complex seepage water sources in the pit and roadway of Dagushan iron mine through qualitative analysis and quantitative calculation. According to the hydrochemical characteristics of the study area, the causes of seepage water at different positions in the mining area were reasonably explained. The results show that there is a possible hydraulic connection or similar source of water body between the bedrock fissure aquifer and the eluvium pore aquifer. The water seepage of 2# roadway mainly comes from bedrock fissure aquifer in the north of mining area. The reason for serious water seepage in the 3# roadway and the western side of the pit is that the fault connects the shallow alluvial pore aquifer and bedrock fissure aquifer. The source of water on the southern side pit comes from the river and groundwater on the southern side of the mine. The results presented here provide significant guidance for the management of mine water seepage problems.

Roof water disaster is one of the most serious disasters in the process of coal mine safety mining in China. The thickness of modern comprehensive mechanized coal mining is large, which has a great impact on the roof aquifer, and the threat degree of water disaster is also increasing. Therefore, the evaluation of the water richness of the roof aquifer is an important work for coal mine water prevention and control. In order to systematically evaluate the water-rich property of an aquifer in a coal seam roof, this paper couples multisource geological information based on an analytic hierarchy process (AHP). The characteristics of the roof aquifer, hydrogeology, and structure are determined to be the main control factors of K2 limestone water richness evaluation. Under the main control factors, seven independent water richness evaluation indexes, including aquifer depth, aquifer thickness, borehole water level, borehole water consumption, faults, folds, and collapse columns, are divided, and a normalized water richness coupling evaluation model is constructed, which realizes the zoning and evaluation of a water-rich aquifer in a coal seam roof.

Aquiclude stability is vital for the realization of water-preserving coal mining. And its evaluation, influencing factors, and their significance analysis are quite topical for the ecosystem conservation. The purpose of this paper was to establish an evaluation index system of weakly cemented aquiclude stability. An evaluation index system was built based on three evaluation factors (subsidence, seepage, and deformation), three subfactors (subsidence gradient, seepage rate, and horizontal deformation), and four evaluation criteria (unstable, weakly stable, medium stable, and stable). The evaluation method was applied to evaluate the index for the case study of Yili No. 4 Coal Mine in Xinjiang, China. Based on the geological conditions of the close-distance coal seams in the mine under study, the main influencing factors and subordinate functions of evaluation index S t a were analyzed. The above three factors’ weights were assessed as 0.1095, 0.3090, and 0.5815, respectively, and the proposed evaluation method’s feasibility was verified by the water level variation in the observation hole. The range and variance analyses were performed to assess the significance of the mining heights of the upper and lower coal seams and the coal seam spacing. The results showed that the aquiclude stability negatively correlated with the mining heights and positively correlated with the coal seam spacing. The decreasing order of influence significance on the aquiclude stability was as follows: upper coal seam mining height, lower coal seam mining height, and coal seam spacing. Water protection mining was an effective measure to control the S t a , and the findings provided a reference value and academic significance for the ecosystem conservation.

Unfavorable geological phenomena such as fault development and weak surrounding rocks are the common challenges encountered in tunnel excavation. However, the conventional rock mass classification method is complex, and the data obtained through disturbed rock samples cannot be used to dynamically and accurately class the surrounding rock in real time. In this study, discrete element method (DEM) is applied to simulate the rock-breaking process by pneumatic rock drill, and the drilling parameters of the surrounding rocks with different classes including drilling rate, vibration acceleration, and vibration frequency, are acquired during the excavation. The simulation results are verified through the data obtained by field tests in Luoping tunnel and Zilinshan tunnel of the Sandu Expressway in Guizhou province, China. Furthermore, a standard database for the dynamic classification of surrounding rocks is established. The numerical simulations reveal a good correlation between the average drilling rate, vibration acceleration, and vibration frequency of drill bit and the class of surrounding rock, and these factors can be used as dynamic evaluation indices for advanced geological prediction during tunnel construction. Overall, the results can serve as a useful reference for advanced geological prediction and dynamic classification of surrounding rocks during the construction of tunnels.

In coal seam mining, the water resistance of the floor composite strata is the key to determining whether water disaster occurs or not and to formulating water control countermeasures. Taking the Pingdingshan Coalfield No. 8 mine and Shoushan mine as the research objects, the thickness ratio of plastic brittle rock, core recovery rate, thickness of effective aquiclude, fault complexity, composite compressive strength, and equivalent water resistance coefficient were selected as the index factors. The comprehensive weight of each index factor was determined by using the entropy weight theory. The water resistance of the J16-17 coal seam floor composite rock in the study area was quantitatively evaluated using the fuzzy variable set mathematical model and was divided into five grades: extremely weak, weak, medium, strong, and very strong. The results show that the J16-17 coal floor composite rock layers with strong and very strong water resistance areas account for 23.64% of the total area, the medium areas account for 58.26%, and the weak and extremely weak areas account for 18.1%. These results provide support for the accurate assessment of water inrush hazards of a coal floor.

The Upper Group 2 (UG2) chromitite reef is a shallow-dipping stratiform tabular orebody in the South African Bushveld Complex, which strikes for hundreds of kilometres. Mining is extensive, with depths ranging from close-to-surface to 2 500 m. Pillars are widely used to support the open stopes and bords. Little work has been done in the past to determine the strength of pillars on the UG2 Reef and design was done using formulae developed for other hard-rock mines. This has led to oversized pillars with consequent sterilization of ore. In this paper we describe a back-analysis of stable and failed UG2 pillars on the Bushveld platinum mines, and provides a strength formula for UG2 pillars. The formula may be used cautiously on all Bushveld platinum mines with similar geotechnical, geometrical, and geomechanical conditions to the pillars in the database.

Up to now, automatic control of the shearer speed has been performed to keep the actual speed at an operator-specified level or to keep the actual power at a stable level without overheating or overturning. However, the problem of control of coal seam cutting by the upper drum of a shearer in the case of a variable angle of drum – coal seam contact has yet to be studied. The aim of this work is to develop a method for synthesizing a system of fuzzy automatic control of coal massif cutting by a shearer drum based on an information criterion for the power efficiency of coal cutting with cutters. In this work, based on an information criterion for the power efficiency of coal cutting with cutters, a fuzzy inference algorithm is constructed for a system of automatic control of coal massif cutting by a shearer drum. In doing so, the parameters of the output linguistic variable term membership functions of the system and fuzzy operations are determined according to the recommendations of the classical Mamdani fuzzy inference algorithm using substantiated fuzzy production rules. The fuzzy inference algorithm constructed in this work is tested for efficiency based on the fraction of effective control actions generated by the fuzzy automatic control system. Using simulation, the efficiency of drum rotation speed control with the use of the proposed fuzzy inference algorithm is compared with that with the use of an uncontrolled shearer cutting drive. The study of the generation of control actions involving the upper shearer drum rotation speed showed that effective control actions were generated in the overwhelming majority of cases (about 93%). The proposed method forms a theoretical basis for the solution of the important scientific and practical problem of upper shearer drum rotation speed control automation with the aim to reduce specific power consumption and the amount of chips.

In view of the randomness of rockfalls shape and irregularity of the bottom floor of working face in steeply dipping coal seams (SDCS), it is difficult to accurately simulate rockfall movement, and it is consequently unable to effectively protect against multirockfalls. Therefore, a method for generating random shape rockfalls based on ellipsoid equation is proposed, and a 3D grid model of real bottom floor of working face is established based on the geographic information system data. In order to verify the accuracy and feasibility of the method and 3D model, the trajectory simulated by Rockyfor3D software is compared, and the proposed method and 3D model prove to be effective in simulating rockfall movement more accurately. Then the proposed method and 3D grid model are applied to solve the problem of multirockfalls protection in numerical simulation, and the main factors affecting the structural stress response of protective netting are analyzed by taking three incident modes of parallel heights, ladder parallel, and the same trajectory. In the simulation, it is found out that the trajectory of irregular rockfalls is greatly affected by the shape of rockfall and working face floor; during the process of multiple rockfalls colliding with the protective netting, the peak stress on the protective netting is inversely proportional to both the time interval between each rockfall and the distance between each rockfall. The findings presented in this research contribute to rockfall prediction and protection against rockfall hazards.

In this study, the X5 KCC in Shiquan Coal Mine was investigated by means of controlled source audio magnetotelluric exploration and borehole television. In this way, the subsection geological structure of the KCC was obtained. Next, the geological and electrical characteristics of each part were analyzed, and it is concluded that the development status of the mud part under coal seam floor is the key part to judging whether water inrush will occur during working face recovery under aquifer pressure. Furthermore, the mineral compositions of purplish-red mudstone and lime mudstone were obtained by performing an X-ray diffraction experiment on the KCC interstitial materials. On this basis, the water insulation properties of the mud part were qualitatively evaluated. Finally, the tensile strength of the mud part was obtained by the Brazilian splitting method, and the water insulation ability of the mud part at the periods when the tunneling roadway and the working face passed the KCC was calculated, respectively. The research results boast guiding significance for safe recovery of the working face passing KCCs under aquifer pressure.

As the human population grows, the demand for space to settle and infrastructure development puts a strain on land resources hence people move to occupy areas of difficult terrain such as mountainous regions and karst environments. The trends in anthropogenic activities mean that there will be increased human interaction with the perilous terrain and consequently geohazards associated with them. Studies on geohazards in Kenya have focused mostly on landslides in mountainous regions but not much has been reported on geohazards that are common in areas of carbonate rocks such as coral limestone. Vipingo coral limestone quarry, a coastal quarry, is taken as a case study as a number of hazardous situations have been encountered during mining. This paper outlines the karst features, their formation processes in the coralline limestone rock mass, and the resultant geohazards. Field visits made to the quarry complemented with previous exploration reports enabled the collection of field data on rock mass characteristics, karst features, and potential hazardous sites were mapped out. Karstification is evident in traces of pores and fissures filled with soil in the upper layers of the rock. Cavities, voids, and caves occur randomly in the rock mass and are the genesis of incidents such as bench collapse, sagging of overlying rock slaps leading to sinkholes. The rock mass is weak and prone to slope failures. Suggestions have been fronted for geohazard mitigation and further research work for the scientific community. Thus, this work constitutes an important knowledge base for infrastructure development and any other quarries around the area, and for those who are settled around this karst environment in order to preempt geo-accidents.

Beka-Gotto is a village of Ngaoundal located in the Adamawa region (Cameroon). The present study is carried out to determine the physical and mechanical characteristics of the local rock massifs, in order to determine their possible uses in various fields of civil engineering. The methodology used consists of petrographic and geotechnical characterization of the different massifs. The rocks crop outas domes or slabs. The rock is light gray. Under the microscope, the rock presents a grainy microstructure composed of plagioclase, potassium feldspar, biotite and quartz. Zircon and opaque minerals represent the accessory phase. With this composition, rock is granodiorite. The geotechnical study, on the other hand, made it possible to understand that, on the physical level, the rock massif has very good properties. In fact, the specific weight on class 6/10 and 10/14 obtained has mean values of ​​2.73 and 2.68 kN/m3 respectively. While the apparent density obtained of the class 6/10 and 10/14 has mean values 1.35 and 1.46 g/cm3 respectively. Mechanically, Los Angeles coefficient is 24-46.3% while the Micro-Deval coefficient is 7-35% and the coefficient of dynamic fragmentation is 18-30%. In accordance with geotechnical standards, with the exception of the Gbago massif, the other massifs have a choc resistance and a wear resistance of satisfactory to limited grade as well as good resistance to dynamic fragmentation and therefore usable in any type of structure.

The mineable coal seam at Qidong coal mine, Huaibei coalfield, is adjacent to the overlying unconsolidated confined aquifer, which may induce water inrush hazards threatening the safe mining. This study presents an information value model (IVM) for the risk assessment of water inrush based on the information value and the geographic information system (GIS). In contrast to the general risk assessment model, this model was considered to improve the selection of the evaluation factor, which predicts the water inrush risk by using the best combination of factors. In general, the selection of the factors always had been decided by individual decision-makers. It was significantly subjective, which, in turn, make the prediction results quite different from the fact. Thus, it is of great significance to optimize the selection of evaluation factors before predicting the water inrush risk. This model was applied to the Qidong coal mine in North China. Then, the prediction results were further verified by the field distribution of water inrush, and the evaluation result is believed to be satisfactory. In addition, the AHP was also adopted for the risk assessment to compare with IVM. The AUC values of AHP and IVM without the optimization of factor selection are 0.6883 and 0.8229, respectively, and are 0.7253 and 0.8494 after the optimized selection, respectively. The results show that the IVM has a better prediction accuracy, and the prediction accuracy is increased after the optimization of factor selection, which indicates the IVM and the optimization could further help the future mining operation.

Steeply dipping, vein and tabular orebodies are traditionally extracted with longitudinal retreat mining methods such as Eureka and Avoca in a bottom-up sequence with delayed backfill. To increase productivity, sill pillars in the orebody are used to separate mining zones thus allowing production to take place simultaneously in two or more zones. While such mining methods are productive, they may be accompanied with high volumes of hanging wall overbreak causing significant unplanned ore dilution. In this work, it is shown through a mine design case study of a narrow vein deposit that a sill pillar could also play a significant role in limiting hanging wall overbreak. To demonstrate the role of sill pillar, a novel numerical modelling scheme is proposed to account for progressive stope wall overbreak. A numerical modelling approach of element death and rebirth is developed to allow for the detected stope overbreak to be immediately removed and replaced with backfill material before upper-level stope extraction. It is further shown that the average overbreak volume could be reduced by as much as 33% when the sill pillar is strategically placed in the lower half of a mine plan.

Landslide hazard analysis is important to mitigate possible landslide hazards and ensure sustainable development of society and economy. Integrating machine learning models into landslide hazard analysis is a common but challenging task for researchers in general. In this work, we introduce a revolutionary framework, the Amazon's AutoGluon, a new open-source library of machine learning models, to analyze landslide hazards related to the 2017 Jiuzhaigou earthquake in west China. We use 11 mathematical models in the AutoGluon to perform the analysis. For each model, the coseismic landslide inventory and 10 environmental and triggering factors are used as model inputs to perform landslide hazard analysis. These 10 factors are altitude, slope, aspect, slope position, distance parallel to the seismogenic fault, distance vertical to the seismogenic fault, distance to the epicenter, lithology, distance to rivers, and distance to roads. The same number (4,834) of random points in landslide and non-landslide areas are selected, 70 ​% of which are used as training points, and the remaining 30 ​% used as validation points. It takes 47.33 ​s for data preprocessing and model training for 11 machine learning models and the best result measured by Roc-AUC score is 0.94. Our work shows that AutoGluon can greatly improve the efficiency of landslide hazard analysis.

The artesian well of Monzoungoudo has been abandoned since 2005. The non-mastery of artesianism springing up at this water point constitutes a waste of the resource and has caused environmental damage. It is a question of an uncontrolled flow of the artesian well induced by the depressurization of the aquifer, resulting in a potential loss of capacity of neighbouring wells and continuous flow of the well at the mouth of its casing. In contact of the recovered water with the surrounding soil, it may generate local flooding, gullying, soil subsidence, the formation of sinkholes and cause damage to the infrastructures located nearby. In addition, the water from the artesian aquifer on the surface migrates to the Monzoun River, while transporting suspended particles or contaminants encountered on its path. The receiving environment of this water could then be affected by an input of turbid water or various contaminants. All these reasons justify the validity of this study, which proposes to address the technique of plugging the abandoned artesian wells of Monzoungoudo in order to stop or control the gushing water. Keywords: Abandons; Artesian well; Captive aquifer; Gushing; Monzoungoudo; Shutter.

With increasing depths of mining, difficult reef geologies, reduced overall mine productivity, as well as the increasing cost lines associated with mining in the narrow tabular property; the current blasting related mining methods prove to be less efficient. This is owing to low efficiency, higher effect on the surrounding rock, possible fly rock, dilution, personnel in danger line and production of toxic gases, etc. These challenges have resulted in a 13.5% (101.3 tonnes) and 2.9% (262.9 tonnes) decrease in gold and platinum production, 14% and 2.6% increase in gold and platinum costs and the rate of change in safety has started to flatten out. Several recent studies emphasize the development and utilization of non-explosive techniques of mechanical rock cutting that are integrated into continuous mining systems, and one of these techniques is reef boring. The work is aimed at determing the most suitable mining method between blasting technique methods (conventional B and P, conventional breast, mechanised B and P, and mechanised breast) and rock cutting technique method (reef boring which involves the drilling of narrow tabular reef and extracting the chippings for processing). The most suitable method is determined through a trade-off study. The trade-off study (mining method evaluation) was conducted through the use of simulations based on BME (Basic Mining Equations) and BFE (Basic Financial Equations) calculations, Risk assessments, Trade-off analysis: weighing, scoring, and comparisons of the mining method. The inputs of the study were derived from the literature survey that was conducted on different mining methods. The background information gathered on these mining methods focussed on ore extraction, material handling, support, labour, equipment, and benefits & challenges of each mining method. Using that background information together with mine benchmarking, a mock mine was created with the following orebody characteristics: thickness of 1.1 m, dipping at 15°, and an average grade of 4.12 g/t at a depth of 1.1 km. This ore deposit was extracted using all five mining methods investigated. The mining parameters for each mining method were based on the literature study information and first principles. The trade-off analysis was based on the selection criteria that includes production, cost, safety, dilution percentage, extraction percentage, flexibility, and automation. Based on the results, reef boring method produces the highest tonnages of 10 651 oz/month, has the highest profit of R303 million/month, highest NPV of R1 423 million, highest IRR of 88%, and highest ROCE of 296%. Due to these factors, the reef boring is the most profitable mining method compared to drilling and blasting methods. Also, it has the least dilution percentage of 2% and the highest extraction percentage of 98%. The reef boring method has the least number of employees on the face (10 people), fewer hazards are associated with the equipment and the reef boring machine causes the least disturbance on the surrounding rock. Hence, it is the safest method with maximised automation. However, even though the reef boring method is more feasible in the paper, practically for high performance the machine should be able to drill 18 h per hole and extract 1000 m and above.

Salah satu cara memanfaatkan batubara bawah permukaan adalah dengan cara mengonversinya ke dalam bentuk gas yang lebih ramah lingkungan melalui metode underground coal gasification (UCG). Cekungan Sumatra Selatan adalah salah satu cekungan batubara produkfif di Indonesia. Kegiatan evaluasi ini bertujuan untuk untuk mengetahui lokasi potensi batubara yang cocok untuk pengembangan UCG. Evaluasi potensi batubara Indonesia untuk pengembangan UCG di cekungan ini, dilakukan dengan cara mengarakterisasi lapisan batubaranya. Batubara cekungan Sumatra Selatan di Daerah Bayung Lencir, Muara Kilis, dan Srijaya Makmur dievaluasi karakteristiknya untuk melihat potensi UCG pada batubara tersebut. Parameter karakteristik yang dievaluasi meliputi peringkat, ketebalan, kemiringan dan kedalaman lapisan batubara, rasio kedalaman dan ketebalan lapisan batubara, batuan pengapit berikut ketebalannya, kondisi hidrogeologis (posisi batubara terhadap akuifer), struktur geologi serta sumber daya batubara. Hasil evaluasi menunjukkan, berdasarkan karakteristik batubaranya, daerah Bayung lencir merupakan daerah yang cocok untuk pengembangan UCG.

Post-landslide high slopes have always been at increased risk for rockfall disasters, posing a considerable threat to the slope toe area and making it very difficult to manage. In this paper, a comprehensive rockfall hazard assessment strategy based on high-resolution terrestrial laser scanning is proposed. A high-resolution digital terrain model was obtained based on terrestrial laser scanning (TLS) and data processing. Combined with a three-dimensional (3D) probabilistic model, the movement of rock blocks is simulated, and the mechanical parameters for simulation are corrected by 3D back analysis. Finally, based on hierarchical analysis process (AHP) and raster calculation, a rockfall hazard map can be obtained. The method was applied to analyze rockfall hazards on the post-landslide rock slope in Ganluo County. It was found that the rockfall hazard of the post-landslide slope is a great threat to the personnel and equipment of the emergency rescue at the site, and its long-term rockfall risk is also a big hidden danger to the railway at the foot of the slope. The planned 3 m high and 1500 kJ energy capacity protection net has 87.22% interception efficiency, but it is difficult to stop the falling rocks with high speed or high bouncing height. According to the characteristics of rockfall hazards, recommendations for rockfall hazard mitigation measures are proposed, including two aspects of rockfall source area remediation and rockfall transport path blocking. The case of rockfall hazard assessment in Ganluo County provides new methods and ideas for the management of rockfall hazard on post-landslide rock slopes.

Geological hazards represent medium- and long-term risks, when they affect urban infrastructure and residential areas as they become a source of danger for the population. In 2000, fracture formation on a couple of streets was reported in the town of Villa Hidalgo, Zacatecas. The first official fracturing report was issued 11 years later and it stated that the fractures were associated with an N–S fault. This paper proposes a hypothesis on the origin of the fractures due to slow land subsidence based on systematic measurement of fractures in frontages, streets, and sidewalks in the locality. The data measured in each fracture were: azimuth, dip, dip direction, length, thickness, azimuth of the extension axis, and fracture density. The fracturing risk and hazard analysis integrates the field data together with the edaphology, geology, slope, population, infrastructure, and services. The risk and hazard range from “medium” to “very high” in a belt oriented N–S of 200 m wide at 100 m to the west of La Ballena-Villa Hidalgo fault, at the eastern edge of Villa Hidalgo graben. The risk distribution area is probably associated with the steplike structure of the basement. Aquifer overexploitation, deficiencies in construction procedures and the geomorphic process also seem to have facilitated the fracture formation.

The article is devoted to the study of the fine-grained lightweight concrete properties on porous aggregates of volcanic tuff from the Kamenskiy deposit in Kabardino-Balkaria, prepared on tuff sand.

Hidden faults in deep coal seam floor threaten the exploitation of coal resources. Under the influence of mining and water confined in the floor, the cemented filler in the hidden fault will be eroded by water flow, in order to investigate the fracture characteristics and water inrush risk of hidden faults in floors above confined aquifer. Using the 27305 working face as geological background, the influence of the seepage scouring filler on the mechanism of water inrush from hidden faults was assessed by developing a stress-seepage coupling model and employing the finite difference method to simulate the seepage process of hidden faults under the combined action of high ground stress and high confined water. The evolution of seepage, shear stress, and plastic zone was also assessed. The influence of the hydraulic pressure of the aquifer and the thickness of a waterproof rock floor on the formation of the water inrush pathway was analyzed. Results indicate that (1) under the influence of mining, the hidden fault experienced the change process of stress stability, stress concentration, and stress release. The shear stress increases first and then decreases. The compressive stress decreases gradually due to stress release. (2) Water inrush disaster will not occur immediately when the working face is above the hidden fault. The delayed water inrush occurs in the mined-out area when the working face advances to 160 m, the floor failure zone is connected with the hidden fault failure zone, and the delayed water inrush channel is formed. (3) With the mining advances, the water pressure of aquifer is the same. The larger-angle fault leads to the thinner thickness of floor aquifer. The greater the influence of hidden fault on coal seam mining, the higher the danger of water inrush.

The Tangab Dam was constructed at a unique geological structure, within a karst valley at the deepest point of a saddle-shaped feature which was formed by tectonic compression of a post-folding shear zone and later uplifting by two salt diapirs. The reservoir water-tightness system was composed of a 20-m-deep cutoff wall, and a 180-m-deep hanging grout curtain with 256 m and 206 m extension, respectively, into the left and right abutments. Since impounding of the reservoir in 2009, water leakage has occurred in 5.8 km downstream preexisting karst springs. To reduce water leakage, two additional grout curtains, as well as extensive treatment works, were added by injecting 11,055 t of cement into the karst bedrock. However, grouting was not as effective as it was expected to be, and the reservoir never filled to its designed normal volume. The fluctuation of water levels in the reservoir and downstream boreholes indicated that grouting successfully reduced head loss in water flow. The reservoir carries the potential to seep water into the karst aquifer along a vast zone at each valley bank since the seepage windows were not covered completely by the hanging grout curtains. The engineering problems occurred at the Tangab Dam site illustrate that conditions where the reservoir is perched above the groundwater and separated with the hanging river valleys are some of the most challenging karst terrains for dam construction in which the successful reservoir impoundment cannot be guaranteed, even by an extensive grouting and sealing program.

Mining operations can drastically affect the stability of nearby areas. A representative case for this has been the Mavropigi mine, a part of an open-pit lignite mining complex in northwestern Greece. Mavropigi is a vast excavation that has reached 150 m depth and has posed severe challenges and stability issues that caused problems in the area. In 2010, noteworthy surface tension cracks appeared near the excavation, leading to extensive monitoring and countermeasures, while various studies were conducted. The present work aims to revisit the case study of Mavropigi from a different than the previous perspectives. Previous studies were based only on continuum approaches, thus understating or ignoring the effect of discontinuities. Nevertheless, the area has an intense tectonic past and faults that interact with soil movements. In this work, advanced, discontinuous numerical modelling through the distinct element method was used to understand better the role of slope fault interaction in the case study of Mavropigi and assess the faults’ effect on the area’s response. The results emphasised the influence of faults on ground movements. The fault’s existence increases the impact of the mine operations on the surrounding area significantly and intensifies the possibility of structural damage in nearby constructions. The analysis confirms that the open-pit mine’s effect on the surrounding area can be amplified under complex geological conditions, in this case, the presence of faults nearly parallel to the slope inclination.

To better understand water inrushes originating from shaft-freezing holes, the hydrogeological conditions and water source were analyzed for a typical inrush case in the Yingpanhao coal mine in western China. The mechanism of this new type of water inrush was identified by considering the stratum movement caused by mining, the concentric annular channels of freezing holes, and the dynamic recharge of multiple aquifers. A new risk assessment model and corresponding grouting method were developed and the problems involving the prediction of water inrush and selection of the optimum grouting position were described. Detailed guidelines for grouting, including the layout of injection boreholes, slurries, grouting pressure and stopping criteria, were proposed. A grouting case targeting this type of water inrush in the Yingpanhao coal mine was introduced. Field studies indicated that open, concentric annular freezing hole channels provide favorable conditions for groundwater migration. The proposed method may effectively inhibit groundwater migration in multiple aquifers and prevent water inrushes through shaft freezing holes and provides an appropriate framework for water inrush prevention for similar mining areas in western China.

The deep Liuzhuang coal mine faces a risk of water-inrush from multi-layer Carboniferous and Ordovician karst aquifers below the coal floor. We analyzed the permeability of a major fault by in-situ water injection tests and found that its overall permeability was low. The hydraulic conductivity of test sections ranged from 3 × 10–4 to 7 × 10–4 m·d−1, with a maximum injection pressure of 1 Mpa. An analytical model of fluid–solid interaction was used to express the influence of mean principal stress and pore pressure on rock permeability, and a 3D numerical model of a pseudo-inclined working face was built to analyze the inrush risk of minor fault zones with varied occurrences and locations. The simulations showed that the risk of a delayed water inrush through the fault zones after fault exposure was greater than that of an instantaneous inrush. The risk of an inrush through the fault zone was greater near the middle of the working face than near the upper roadway; the risk of an inrush through the fault zone near the lower roadway was relatively small.

Shallow cavities, such as karstic caves in carbonate bedrock and near-surface underground mine workings or tunnels, constitute serious hazards for people and existing constructions due to the risk of collapse and subsidence. This phenomenon is growing fast with climate change causing damage to buildings and increased urban development costs. Karstic features, voids, surficial dissolution, fissuring, alteration and unconsolidated material are thus major challenges for geophysical methods that could play a major role in detection. Recent investigations have reported good results for cavity imaging using surface wave seismic methods. However, despite successful case histories, business as usual void detection is still challenging due to the complexity of near surface materials and probably a lack of understanding regarding the interaction of surface waves with voids. Recent data acquired in the context of a search for underground unpaved cavities provide new insights into the use of surface waves for the detection of these objects. Considering the findings, it appears that surface waves penetrating above and below the void may still propagate horizontally without clear features of altered propagation characteristics with respect to different actions, variations in dispersion, or both, which encourages rethinking of the systematic nature of diffraction research in operational applications.

For the sake of studying the catastrophe mechanism of stress-fissure coupling field in mining close distance seams in southwest China, a test working face in Guizhou province in southwest China is adopted and researched by the methods of numerical calculation and similar experiment. When the working face advances to 180 m in 4# coal seam in a similar experiment, the overlying rock breaks to the central base plate of Yulongshan limestone, and the conductive fractures run through the Changxing limestone karst cave and Yulongshan limestone karst cave. When the 1402 working face advances to 350 m, the top of vertical karst caves in the middle of the model produces extrusion damage, forming a penetrating water inrush passage. When the 1402 working face advances to 480 m, the top slab of the working face comes under periodic weighting with the short step. Besides, the mining of 9# coal seam starts after 4# coal seam in mining close distance seams. When the working face in 9# coal seam advances to 340 m in numerical simulation, the maximum opening of the overburden fractures is 51.16 mm. The fractures in the roof are mainly caused by the periodic breaking and falling of the basic roof, connected with the floor fractures of 4# coal seam. When the working face in 9# coal seam advances to 500 m, the maximum opening of the overburden fracture is 93.09 mm. Specifically, as the working face advances, the opening of fracture in the roof after collapse of the basic roof periodically is mainly greater than 5 mm, and the compaction closure is mainly 1 mm-5 mm. The fractures in the gob floor are mainly 0.1 mm-1 mm, and the fracture opening of the collapsed rock mass in the gob is mainly 1 mm-5 mm and greater than 5 mm. The karst caves in the overburden reduce the periodic weighting step of working face and play a guiding role in the direction of fracture development and water inflow passage formation. The karst caves are connected to surface waterfall holes and trap pits, and atmospheric precipitation recharges the water in the caves. The research results can be treated as an important basis for the prevention and treatment for water inrush disaster in mining close distance seams in the karst area of southwest China.

With theurbanization rate's rising and three-dimensional expansion and development of urban, the identification of underground buried faults has become the key factor of earthquake risk in urban underground space and surface area. As a typical method of detecting blind faults in underground space, shallow seismic prospecting technology plays an important role in judging and avoiding potential risks such as underground faults in the process of urban expansion and site selection. In this paper, shallow seismic prospecting technology is adopted, and optimized processing technologies such as parameter test, tomographic correction, pre-stack denoising, fidelity and consistency processing, correction iteration, migration imaging, and time-depth relationship deduction are adopted. Underground faults are identified and interpreted in the studied urban area, and fault risk assessment is carried out based on fault characteristics, scale, distribution and overlying strata, thus providing suggestions for regional pattern and construction of urban planning.

The impact of coal mining will produce a reservoir due to cutting and excavation from the mined area. If it is left without any effort to improve the environment due to mining it will have an impact on the surrounding environment. Research conducted by the author to determine the effect that occurs with a reservoir due to coal mining in the surrounding area. Based on measurements using the geoelectric method, it can be seen the condition of the soil layer in the reservoir and surrounding areas so that it can be estimated the movement of underground water in the aquifer layer. By using a piezometer around the reservoir it can be seen the change in the level of the underground water level at a certain time and the water level in the reservoir is measured in elevation so that it can be predicted the flow direction that occurs. From the results of the study obtained the underground water level has a greater value than the water level in the reservoir, especially in the rainy season. This activity is the initial stage of the study to determine the effect of the reservoir on underground water conservation. For the next stage measurements are needed throughout the year by installing logers so that data can be recorded automatically digitally and doing model simulations using Modflow software to predict the effect of reservoirs on underground water conservation in the long.

Quantitative inversion of accidents is an important work of finding the cause of accidents and avoiding their recurrence. However, quantitative inversion of accidents is difficult due to the lack and limitation of accidents monitoring information. Focusing on water-inrush incidents of Jiguan Mountain tunnel, this paper proposes a set of workflows to find out the missing conditions and quantitative inversion of accidents by flow analysis and structural safety analysis on the basis of investigating the rain capacity and water outflow in water-inrush incidents. First, hydraulic boundary in water-inrush incidents is acquired by analyzing the relationship of catchment, infiltration, and accumulation of rainwater in karst pit using the flooding algorithm of ArcGIS and the topographic mapping of UAV photogrammetry. Second, the permeability coefficients of karst infiltration zone and tunnel surrounding rock are acquired by two-step decoupling and inverse analyzing the water inflow, flow rate, and interval time between rainfall and water inrush. Third, tunnel accidents of the overload of tunnel lining induced by the catchment and infiltration of karst pit under extreme rainfall conditions are numerically simulated by using FLAC. The results indicate that quantitative inversion of water-inrush incidents reveals the process and cause of accidents and provides the safety index of tunnel structure. Not only is the water-inrush incidents of karst tunnel controlled by hydrogeology conditions, but also the rainfall recharge should not be ignored.

As one of the most serious shock dynamic disasters in coal mining, rock burst only occurs under the certain geodynamic environment. Geodynamic is the necessary requirement for the occurrence of rock burst, and the disturbance of mining engineering is the sufficient requirement. In terms of the fault structure, the method of geodynamic zoning is used to classify fault structure forms of rock burst in mines, and a model of geological structure is established to reveal the connection between fault structure and mine engineering. Besides, the influence of fault structure on rock burst is analyzed, and the controlling mechanism of the fault structure on the tectonic evolution of the mine area and the occurrence of rock burst is revealed. This research provides a treatment plan for the prediction and prevention of rock burst and guides the safe production in the coal mining engineering.

Aiming at the phenomenon that many dynamics occur frequently in working face or roadway when the first mining face of mine A, 2-2upper201 is driven to the edge of water-rich area, the effects on original rock stress by draining water-rich area and rockburst risks in two different conditions of drainage and no-drainage are studied through some methods such as theoretical analysis and numerical analysis, based on working face 2-2upper201A(the second working face of Mine A). The findings are as follows: ①The drainage in water-rich area can damage aquifer, resulting in stress decrease inside damaged area and stress concentration in the edge; ②Considering the effect by draining water-rich area, rockbust scope and degree in damaged area will change. In detail, the range below water-rich with risk will shrink and degree of risk will decline, while the edge and outside of water-rich area will enlarge as risk rises. The field monitoring indicates that in the process of mining, stress increments on measure spots rank as the order of from large to small as follows: edge > outside > inside. When working face is driven to the edge of water-rich area, many drastic dynamics like coal blasting, wall carving will occur on the wall, which suggests that draining water-rich area has a great impact on rockburst risk of working face. The research result has very important guiding significance to rockburst prevention in water-rich area.

Coal bump often occurs in coal mining among many working faces in mine group under the control of large geological bodies. In order to study the coal bump mechanism between adjacent working faces under the conditions of large fault and huge thick overburden conglomerate, this paper regards Yima mining area as a practical engineering background and theoretically analyzes the mechanical behavior of overlying rock in the spatial structure. Then, the deep-ground and whole-space measurement is carried out in the 13230 working face of Gengcun mine and 21121 working face of Qianqiu mine. The results show that the basic structural unit in Yima mining area is composed of two goafs, middle coal pillar, and overlying conglomerate. Under the condition of nonsynchronous mining in adjacent working faces, there is a comovement effect similar to lever’s “prying” phenomenon in thick conglomerate beam—the conglomerate strata above larger goaf side induce an overall uplift movement of the corresponding strata above smaller goaf side, and uplift length of the conglomerate strata is related to the mining length, coal pillar width, caving angle, and coal-conglomerate distance. The results of surface subsidence, microseism, and stress in the two working faces verify the conglomerate’s phenomenon of comovement effect and disturbance range and further explain the role of active movement of F16 fault and overall causes of huge thick conglomerate on the coal bump. The vertical stress of the 13230 face is relatively low at the beginning, and high horizontal stress by fault activation causes typical bump accident with the horizontal sliding of coal body. With the increasing development of 13230 face, the intensity and frequency of coal bump in horizontal direction decrease obviously, but with high proportion in vertical direction. The results provide a theoretical basis for the study on the mechanism of coal bump between two adjacent working faces under the conditions of huge thick conglomerate and large thrust fault.

Deep mining is the current and future mining focus in the coalfield of North China. Therefore, it is necessary to establish a water inrush assessment method suitable for deep mining. The conventional water inrush coefficient ( T ) method is simple to use, but its accuracy is low when the mining depth is very small or large because it neglects the role of the aquifer water yield. The main purpose of this paper is to introduce a simple water inrush risk assessment method that is more applicable in deep mining than the T method. In this study, the hydrogeological characteristics in deep mining were studied and the role of the aquifer water yield in water inrush was analyzed. Afterwards, an improved T method considering the aquifer specific yield ( q ) was established. In the new method, the critical water inrush coefficient changes with changing q following a negative correlation. The parameter thresholds were determined based on systematic data analyses of 186 mining cases. The results of the statistical analysis show that the accuracy of the new method at different mining depths is higher than that of the T method.

This research work presents the rock mass characteristics and tunnel support system recommendations for hydroelectric power tunnels at Dasu dam site Pakistan. Two inverted U-shaped tunnels are proposed at the left bank of Indus river. The tunnels have inlet portals at an elevation of 773.00 m and outlet portals at an elevation of 758.00 m. The thickness of rock cover above the tunnels is between 100 and 200 m. Three types of rock are encountered at project site including Granulite, Amphibolite and Gabbronorite. Granulite rocks are encountered along the alignment of tunnels. Rock mass is classified using Rock mass rating (RMR) and Tunneling quality index (Q system). Support system is suggested based on values of Q and RMR. Correlation between Q-index and RMR is also derived.

This article presents a comprehensive study of percussive-abrasive active stone tools from Chagyrskaya Cave, using experimental use-wear and statistical methods, supplemented by 3D-modeling. Experiments combined with use- wear analysis allowed us to determine the functions of these tools by comparing the working surfaces and use-wear traces in the Chagyrskaya samples with those in the reference samples. As a result, we identified 19 retouchers, four hammerstones for processing mineral raw materials, and one hammer for splitting bone, which indicates the dominance of secondary processing over primary knapping in the Chagyrskaya lithic assemblage. Using statistical analysis, we traced the differences in the dimensions of the manuports and lithics under study. These artifacts are a promising and underestimated source of information for identifying working operations associated with stone- and bone-processing; moreover, they can provide new data on the functional attribution of sites and the mobility of early hominins.

Discriminating water inrush sources efficiently and accurately is necessary to control water in coal mines. We combined the improved genetic algorithm (IGA) and extreme learning machine (ELM) methods and applied this new method to the Zhaogezhuang mining area. The IGA-ELM method effectively solved the complex non-linear problems encountered in identifying water sources and proved to have several advantages over conventional methodology. The IGA for the hill-climbing method was adopted to use the weights and thresholds of the ELM, which overcame the prematurity of the traditional genetic algorithm and the instability of the ELM model. Three types of water were identified in different aquifers of the Zhaogezhuang mining area: SO4-Ca in the Laotang water, SO4·HCO3-Ca in the Ordovician limestone water, and HCO3-Ca in the fractured sandstone roof of the no. 12 and 13 coal seams. The water sample recognition was 95% accurate, which proved that the water inrush source in the Zhaogezhuang mining area was accurately identified by the IGA-ELM model.

Deformation and failure of overlying strata caused by underground mining can result in the leakage of overburden aquifers, seriously threatening underground safety and the surface environment. However, conventional methods such as simulation and theoretical calculation cannot comprehensively reflect the dynamic movement of the overburden during mining. This study, therefore, applied two distributed optical fiber sensing (DOFS) technologies, Brillouin optical time-domain reflectometry (BOTDR) and fiber Bragg grating (FBG) sensing technologies, to quantitatively monitor overburden movement in real time. Results indicate that tensile failure dominated in the overburden during mining, and strain accumulation generated mostly at the lithologic interfaces and loess interior. The displacements of bedrock and loess layers reached their maximum values of 76.65 mm and 59.61 mm, respectively, when the excavation face had passed the sensing borehole by 83.16 m. The water-flowing fractured zone (WFFZ) penetrated the bedrock layer and 4.35 m into the loess layer, and it reached the maximum height 225.43 m when the excavation face had passed the sensing borehole by 94.36 m. The fracture angle of roof rock strata was 67.29°. Compared with the microresistivity scanning technology and numerical simulation, the DOFS technologies could more accurately determine the maximum height of the WFFZ. The results are of engineering significance for underground safe mining and surface environmental protection.

Slope failure in the form of rockfall is a common phenomenon that occur in the hilly ranges of Himalayas. Mizoram, being a part of it experiences a high rate of rockfall throughout the year especially during the monsoon season. This paper focus on frequent rock fall along the State highway between Aizawl to Lunglei via Thenzawl at Midumkham, Sumsuih village. Damage of passenger vehicles, public goods carrier trucks, private vehicles and road blocks are the common phenomenon due to various forms of landslide within the study area. The death of a couple on 14th October 2016 due to rockfall within the study area captivate attention of government as well as the local about the condition of the area. Thus, detailed study of the area becomes mandatory so as to reduce rockfall and to educate the government and locals about the actual condition of the area. Field reconnaissance has been carried out to collect joint data for kinematic analysis. The behaviour of rockfall was determined by kinematic analysis using Rocscience software Dips 6.0, the stereograph shows that toppling, planar and wedge type are the potential modes of failures. The rock beddings are classified based on RMR (Rock Mass Rating) and SMR (Slope Mass Rating). About 90% of the selected site shows that low RMR as well as SMR value. The RMR values of the rock exposed in the study area indicated a very poor quality of rock mass. The average stand up time obtained 30 min for 1m span suggest high rate of erosion of rocks in the area. The rock slopes represent Class V of Romana classification, considered as very bad rock mass and completely unstable. The low value of rebound number and strength of the rock along with presence of numerous joints determined the high vulnerability of the study area