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2023 | Buch

Proceedings of the 10th Asian Mining Congress 2023

Roadmap for Best Mining Practices vis-à-vis Global Transformation

herausgegeben von: Amalendu Sinha, Bhabesh Chandra Sarkar, Prabhat Kumar Mandal

Verlag: Springer Nature Switzerland

Buchreihe : Springer Proceedings in Earth and Environmental Sciences

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Über dieses Buch

Rising concern about climate change and strong societal expectations with increasing complexities of mineral deposits being mined, call for more innovative exploration and exploitation technologies with higher productivity and recovery including eco-friendly strategies and policies in place for long term sustainability of the mineral Industry. It is now ardently necessary to identify and define the best mining practices addressing societal needs.

In view of these, The Mining, Geological and Metallurgical Institute of India (MGMI), established way back on 16th January 1906, and one of the oldest institutions of this kind in the world, is organizing the 10th Asian Mining Congress (AMC) during November 06-09, 2023 in Kolkata, India with the Theme, “Roadmap for Best Mining Practices vis-à-vis Global Transformation”. The AMC and International Mining Exhibition (IME), held concurrently, are flagship international events organized by MGMI biennially since its centenary year. This series have provided ample opportunities to all stakeholders including practicing engineers, machinery manufacturers, planners, regulators, academicians, scientists and policy makers, for sharing their knowledge, experience and expertise and exhibit their products that can benefit the mining and mineral industries not only in the Asian region but also globally.

This proceeding of 10th AMC contains the articles written by eminent persons and stalwarts in their respective domains. It is a collection of contemporary articles narrating recent advancements in mining sector.

Inhaltsverzeichnis

Frontmatter

Exploration, Estimation, Geostatistics and Hydrogeology

Frontmatter
Geostatistics in Exploration and Mining

Geostatistics in exploration and mining, over the last eighty years, has witnessed its progress starting with linear kriging, and then advancing to nonlinear kriging, non-parametric kriging, conditional simulation, multi-point statistics and machine learning geostatistics. Corresponding to these advancements, it was felt necessary that a geostatistical modelling study needed a proper connection between geology and geostatistics. The manner of integrating geology with geostatistics can be accomplished by carrying out geostatistical modelling in combination with geology of deposit, mineralisation controls, and zonation of the deposit into several geological ‘domains’. An adequate understanding of deposit geology is, thus, an essential pre-requisite to a geostatistical modelling study. It goes without saying that geology controls the distribution of geologically complex grades, hence it is crucial that geology direct estimation modelling rather than estimation modelling direct geology. An improved understanding of type and characteristics of mineralization is achieved only through a suitable integration of deposit geology with relevant geostatistical technique(s).

Bhabesh C. Sarkar
Prediction of Water Inflow in a Proposed Underground Coal Mine of the Rajgamar Dipside (South of Phulakdih Nala) in Chattisgarh, India

A Hydrogeological investigation has been carried out around Rajgamar-dipside (SOI Toposheet no. 64J/15) to predict water inflow in a proposed underground coal mine. The Groundwater table in the study area, is in general, gently undulating and is shallow with an average elevation of 348 − 355 mamsl, and occurs at a depth of 0.5 − 6m below ground level depending upon topography. The groundwater flow-lines converges from north, south and east toward west-central part (Rajgamar) of the study area. Drainage morphometry indicate significant overland flow in the low topography areas leading to excessive soil erosion. Natural seepage rates vary between 4 − 43 ml/cm2/min. Solution sink-holes and pocks ranging in diameter of 4 − 10 cm to 0.5 − 1 m diameter occur densely within the rocks of Kamthi and Barakar Formations. These solution pits link up laterally and vertically to develop networks of channels that serve as free passage for fast infiltration and subsurface flow of water. Field data and petrophysical properties indicate a possible inrush of groundwater at places through underground solution channels and local fractures within shallow depths (~20 m) and a steady inflow of 4397 gpm to 19834 gpm distributed over a corresponding progressive depth of 10 m to 330 m respectively in a proposed underground coal mine for a gallery whose height is 2.5 m, width is 4 m and length is 1000 m. The study will help mine managers to optimise the pumping rate for dewatering during mining activity.

Mrinal Kanti Mukherjee
Reserve Estimation Through Conventional Method and Computer-Aided Software: A Comparative Case Study

Reserve estimation, most responsible and irreplaceable task, is carried out at all the stages of a mining project to estimate the quality and quantity of mineral deposits. Accurate reserve evaluation involves a precise assessment of quantity, quality, and sustainability. Various advanced mine planning software are globally available but due to high capital cost most of the mine operators opt for conventional methods for reserve estimation. The present study encompasses a case study of Manoharpur coal block comparing reserve estimation by the cross-sectional method and Minex software based on input data of 238 drill holes and comparison with the actual production. The estimated reserve obtained by the Cross-sectional method and Minex software was 6216695 t and 5619278.33 t respectively. However, the actual production of coal as per the proposed profile was 5251365.86 t. The surface profile of the mine has been obtained by a 3D terrestrial laser scanner. The slight variation in the surface profile, dilution, and cutting-edge outline could be the cumulative parameters affecting the actual production with 7% variation. The Minex software is observed to be more reliable in comparison to the conventional method as the former covers all small deviations in reserve profiles unlike in the latter method.

Anand S. Sharma, Amar Prakash, Sujit K. Mandal, K. Prasanth, Dilip Kumbhakar, Prerna Jaiswal
Non-Gaussian Copula Simulation: A New Approach to Recoverable Reserve Estimation in Indian Open-pit Copper Deposit

In a prominent open-pit copper mine in India, a non-Gaussian copula-based simulation model is developed to estimate recoverable reserves. This groundbreaking research serves as an investigation into the potential and effectiveness of copula-based simulation models in the field of reserve estimation. The methodology involves comparing two specific selectivity curves: grade-ore tonnage and grade-metal tonnage. These curves are constructed using the copula-based simulation technique, as well as multi-Gaussian kriging, disjunctive kriging, and actual production data derived from blasting operations within the mine. The results indicate that, in the context of estimating recoverable reserves, the copula-based simulation method outperforms both multi-Gaussian kriging and disjunctive kriging.

K. Dinda, B. Samanta

Mine Planning and Production

Frontmatter
Mass Production Technologies for Underground Coal Mining in India: Status, Challenges, and Prospects

The current trend in coal production in India shows that underground mining contributed less than 5–8% of the total coal produced. On the other side, the contribution of opencast mining to coal production is at its peak. This trend is not sustainable in the Indian scenario due to environmental issues, coal quality problems, and socio-economic stresses due to opencast mining. The solution lies in the adoption of Mass Production Technology (MPT) in underground mining which can compete with opencast mining in terms of OMS and production rate. Furthermore, Coal India Limited (CIL) has also launched a mission to upscale the coal production from underground mines to 100 million tonnes by 2027–28. Therefore, to advocate MPT and its diffusion in the Indian mining industry, this keynote discusses the existing mining methods and potential MPTs for exploiting deep-seated coal deposits in India. The MPT for underground mining has been defined and the eligible technologies are presented. The focus has been made on Longwall Technology which is one of the finest candidate technologies for MPT in India. Furthermore, the challenges in adoption in the Indian coal mining industry have been elaborated with real cases. Finally, the prospects in R&D, testing, and policymaking for smooth adoption in Indian coal mining have been deliberated. In sum, this keynote can enrich the knowledge of practising mining engineers, mine planners, and policymakers in adopting MPT for underground coal mining in future.

Arvind Kumar Mishra
Sustainability of Underground Coal Mining in India Vis-a’-Vis Coal Mines Regulations, 2017

Coal will continue to play dominant role in meeting the growing demand of energy in India. Since nationalization of coal mines, production from underground mines in India has drastically declined over the years while production from opencast mines has grown significantly. Proved and established mass production technologies for underground mining are highly productive and safe all over the world and it must find it’s way in underground coal mines of the country, since surface mined coal can not meet the projected demand of coal in future. Further large opencast mines are known for it’s nuisance for major environmental damages.Health, safety and welfare of workmen engaged in belowground workings of coal mines is still an area of great concern in India. Although wages increased considerably, in nationalized coal sector but working environment is still not satisfactory. Age old practice of Bord & Pillar method creates more unsafe conditions in the mine in terms of risk of fire, explosion, inundation etc., requiring stringent statutory obligations, apart from inadequacy of ventilation and lag in roof support, compared to established practices. It’s also a fact that cost of coal production by underground operations goes down drastically with quantum jump in output.This paper looks at the prevailing mining practices in underground mines in India vis-a’-vis new conditions incorporated in Coal Mines Regulations,2017 thereby need for reorganization/planning of large underground coal mines with an aim for large output from a single mine.

Mihir Choudhury
Dump Slope Stability Rating and Risk Assessment in Opencast Coal Mines: A Case Study

As a part of this paper, detailed risk assessment (identification of hazards, determination of risk score and control measures) was carried out for dump failure in an opencast coal mine. Risk Assessment of dump failure revealed that the hazard i.e. death/injury of unauthorized persons entered near the toe of the OB dump has the highest risk score of 500 whereas the hazard i.e. sliding of external OB dump due to foundation failure has the lowest risk score of 50. Based on individual point ratings for each of the main factors affecting dump stability, the dump stability rating (DSR) was estimated and found to be 400–500 for the mine under consideration for study and the dump stability class was determined as Class II and corresponding category of failure hazard is Low.

Satya Prakash Sahu, Pradeep Kumar Mohanty, Singam Jayanthu
Understanding Runout Behavior of Overburden Dump: Insights for Buffer Zone Design in Open Pit Coal Mines

Failure of in-pit overburden dumps in open-pit coal mines triggers the flow of debris toward the active working face, posing threats to personnel and equipment safety. The heterogeneous nature of these dumps and the limited understanding of their engineering behavior contribute to frequent failures. To mitigate the risk of unwarranted failures and enhance safety measures, the establishment of a buffer zone surrounding the periphery of in-pit dumps is necessary, restricting or prohibiting worker and machinery movement. Determining the size of this buffer zone depends on the potential mobility of the failing mass, determined by its runout length and runout area. Although pre-failure deformational behaviors have received significant attention in scientific literature, the need for comprehensive post-failure runout studies has only recently been recognized, driven by the increase in waste dump failure accidents. To address this knowledge gap, a laboratory-scale debris flow flume was developed to investigate the influence of material gradation and slope angle on the runout characteristics of overburden (OB) material. Experimental investigation reveals a strong correlation between runout characteristics and the Fines/Coarse ratio in the debris mixture. Notably, a critical limit of Fines/Coarse exist before and after which the general trend in runout length contradicted each other.

Anup Tiwari, Bibhuti Bhusan Mandal, Khanindra Pathak
Bridging Efficiency and Safety: A Case Study of Extraction of Thick Coal Seam Having Low Incubation Period Using Continuous Miner

The extraction of thick coal seams developed on pillars by underground mining has been a chronic problem in India. The problem increases when the incubation period of such seams is very short, as in the case of Raniganj coalfield. Fast extraction, effective management of mining-induced stresses, and early detection of spontaneous heating and fire incidents are crucial during the liquidation of these thick seams. Minimizing coal loss in the goaf and selecting an appropriate support system for the high roof are important considerations. The paper presents a case study of Khottadih Colliery, where Continuous Miner (CM) technology is successfully employed to extract R-VI seam of 5.4 m thickness in a single pass. The R-VI seam has a very low, around 90 days incubation period and is developed along the floor in Bord and Pillar pattern up to a height of 2.8 to 3.0 m. Overlying seams are extracted by an opencast project and backfilled, with a 23 m high overburden dump above the CM panels. The use of CM with a single-pass height extraction of 5.4 m is the first such application in the Indian coal mining industry, exceeding the previous 4.6 m limit, thereby maximizing productivity while minimizing associated risks.

Prabhat Kumar Mandal, Rana Bhattacharjee, Nilabjendu Ghosh, Awanindra Pratap Singh, Subhashish Tewari, Arka Jyoti Das
Performance of Mechanised Depillaring Operations with SDL and Continuous Miner Technology - A Comparative Study

All countries, who are rich in mineral resources and able to exploit them in judicious and safe manner, achieve faster growth in industrialization and become model of development of modern civilization. India is placed at 3rd position in terms of production. But maximum coal production is from opencast and more importantly the production from underground has a declining trend. To arrest this trend coal companies have started thinking to introduce mass production technology such as continuous miner in underground mines. Due to faster rate of production and advanced safety feature of continuous miner loss of coal is minimized and safety of workers is enhanced along with ensuring conservation. The present study is aimed to analyse overall performance of continuous miner technology and to highlight key points to be taken care of for achieving higher and better utilization of this valuable resource. Cost of production, productivity, and maximum production in the depillaring panel/day of the Side Discharge Loader workings with semi-mechanisation are to the tune of Rs 11000/day, 0.79 and 500 Ton/day respectively whereas with Continuous Miner with full mechanisation the same figures becomes Rs 3800/day, 8.14 and 2000 Ton respectively in typical geomining conditions of depillaring workings in CCL.

Mithilesh Kumar Mishra, Singam Jayanthu

AI/ML Applications and Smart Mining

Frontmatter
AI-Based New Tool for Semi-Automatic Interpretation of Reflection Seismic Data

Seismic measurements on the Earth’s surface are extensively used to delineate subsurface geologic features for the exploration of geo-resources and understanding geodynamics or seismo-tectonics. Over the decades, seismic attributes (properties or characteristics) extracted from 3D seismic volume have revolutionized interpretation of subsurface geologic environment. It is the high performance computing systems that have allowed processing of voluminous data within a reasonable time, but the interpretation by human analysts still remains tedious, particularly in a complex area. This has necessitated automatizing the process of interpretation to reduce human intervention. We have designed several work flows for merging multiple attributes related to a subsurface structure into a single ‘meta-attribute’ that has allowed to delineate the 3D configuration of that feature from a large volume of data, even in a complicated region. This artificial neural based approach integrates the intelligence of human assisted machines over a small volume of data, followed by applying the trained system to entire volume for exploring the geologic feature quite accurately at a fast rate. Success stories from a variety of basins across the world including India would be presented.

Kalachand Sain
Machine Learning Based Prediction of Spontaneous Combustion Susceptibility of Coal using its Intrinsic Properties: A Safe Smart and Sustainable Mining of Coal Approach

Spontaneous combustion and coal mine fire cause widespread damage to accessible coal resources of Jharia coalfields and pose a serious threat to the safety of mine personnel. To study the prediction of spontaneous combustion (SC) susceptibility of coal, 30 samples from various coal seams throughout the coalfields were collected and their intrinsic properties viz. Physical, proximate, ultimate and petrographic determined in the laboratory. The proposed machine learning techniques then were able to classify coal seams based on its intrinsic properties into three SC categories of very risky, risky and low risk. For better visualization of the multi-dimensional data principal component analysis (PCA) projected the obtained clusters along the intrinsic properties as axes in a 2-dimensioanl space. Then wet oxidation potential (WOP) which is a susceptibility index is used to find a relationship with coal intrinsic properties using three machine learning models viz. Support vector machines (SVM), random forest (RF), and elastic net (EN). The clustering results match the laboratory analysis of WOP of each sample and the on-field knowledge. RF algorithm proves to be the best model for the given data to define a relationship between WOP and the intrinsic properties of coal in Jharia region.

Siddharth Agarwal, Atul Singh, Pratibha Sharma
Machine Learning Applications: Coal Fire Prediction Using Graham’s Ratio

As the mining industry has evolved, there has been a rise in the number of incidents at mining sites caused by active flames in underground coal mines. It is a complex process that jeopardizes the miner’s life and property. The harm inflicted by fire threats in recent history has drawn the attention of the authorities toward implementing measures that will lessen the risk of natural disasters. It is impossible to exaggerate the significance of this finding in terms of its potential to reduce the risk associated with coal’s ability to self-heal. This study intends to show evidence that machine learning may be successfully utilized to produce accurate forecasts regarding self-healing, and its primary objective is to accomplish this goal. This research led to the development of AdaBoost classification procedures, which were then used to create methods for anticipating the occurrence of spontaneous fires in UG coal mines. The effectiveness of different ML models is compared to one another using quality metric criteria.

Surendra Kumar Dogra, Jitendra Pramanik, Singam Jayanthu, Abhaya Kumar Samal
An Approach for Implementation of IoT Enables Smart Environmental Monitoring and Strata Monitoring System for Underground Coal Mines

IoT is the new standard that integrates various technologies and aspects from varied methods. Pervasive computing, sensing technologies, embedded devices, ubiquitous computing, internet protocol and communication technologies are merged for system formation where the digital and real worlds meet.Through the setup of IoT into day-to-day objects, they are modified into smart objects that gather information from the surroundings, controls and interacts with the physical world. Working in the underground coal mines is complex and risk-oriented due to its long and narrow tunnels, complex structures and high probability of various gas concentrations in the coal mines. This leads to many chances of explosion causing the death of workers. Hence, suitable wireless communication is essential for solving the existing issues in the underground mines. Taking all these existing issues of the coal mines into account, IoT based wireless and real-time monitoring system is introduced here to track and monitor these mines for ensuring miners’ safety. This paper is mainly focussed on designing and developing of IoT permitted strata condition and a sub-surface mine environment monitoring a web-based system for decision making to predict sub-surface environments.

Shankhajit Mitra, S. K. Chaulya, Dheeraj Kumar, Ashish Soni
Vision Enhancement System for Foggy Weather in Opencast Mines

The presence of fog and smog in the environment hinders the visibility of heavy earth-moving machinery operators in opencast mines. The paper describes an intelligent driving assistance system to enhance the drivers’ visibility in opencast mines during harsh weather conditions. The system integrates different devices like proximity radar, infrared cameras, global navigation satellite systems (GNSS), wireless devices, anti-collision laser lights, and image processing algorithms (image dehazing, image stitching, and object detection using artificial intelligence technique) for assisting the drivers to navigate in dense foggy conditions. The system aids the operators in driving during dense fog environments, generates an audio-visual alarm while facing any obstruction, and mitigates colloidal vehicle accidents. The final processed output of cameras, GNSS-based navigation using 3D geo-tagged digital mine map, and proximity radar are displayed on the dashboard screen fitted in forward-facing of driver’s seat. The system incorporates artificial intelligence, image processing techniques, and advanced analytics for dehazing foggy video footage, proximity warning, object detection, and fleet management.

Swades Kumar Chaulya, Girendra Mohan Prasad, Monika Choudhary, Naresh Kumar, Virendra Kumar, Vikash Kumar, Abhishek Chowhury
Interpretable Predictions: Machine Learning Approaches to Understand Slope Stability in the Presence of Joint Networks

This study leverages machine learning algorithms to predict slope stability in various types of jointed rock masses. Employing a dataset of 40290 cases derived from numerical simulation using the Shear Strength Reduction (SSR) technique, the research analyzes slope stability in the presence of different joint types. The utilized models include Linear, Ridge, Lasso, Random Forest, k Nearest Neighbor, Decision Tree, XGBoost, and AdaBoost regression. The results indicate that XGBoost and Random Forest outperform other models on test datasets, as measured by Mean Absolute Error and R-squared values. Notably, the findings highlight the crucial role of joint networks in slope stability prediction, addressing limitations in previous research. The study also underscores the balance between model performance and interpretability, with complex models providing higher predictive performance at the cost of transparency. Overall, this research presents a robust approach to slope stability prediction, enhancing decision-making in geotechnical engineering and contributing to safer slope design and management.

Sudhir Kumar Singh, Debashish Chakravarty
Machine Learning Techniques for Predicting Health Risk of Mining Vehicle Operators Subjected to Whole-Body Vibration

Occupational health and safety in mining operations hold paramount importance, encompassing multifaceted aspects aimed at ensuring the well-being of workers. Prolonged whole-body vibration (WBV) exposure among mining vehicle operators has been associated with a range of adverse health effects, most notably musculoskeletal disorders (MSDs) such as chronic low back pain and lumbar disc herniation. This study aims to develop a predictive model utilizing machine learning techniques, specifically Artificial Neural Networks (ANNs), to forecast the health risk associated with WBV exposure under different operational conditions. The vibration data of the tippers were acquired during its routine operation in an opencast mine in central India. The dataset encompassed various operational factors, including haul road type, operator weight, speed, and payload, under which an ANN model was trained to predict the resulting vibration exposure magnitude. ANN model was developed using Multilayer Perceptron (MLP) architecture to predict the health risk. Backpropagation was used to adjust the weights of the connections between neurons in order to minimize the difference between predicted and actual output. 70% of the total data was used for training and the others for data testing (15%) and validation (15%). The correlation coefficient for the training and test of the optimum network were found to be 97.58% and 97.4%, respectively indicating an excellent correlation between the predicted frequency weighted root mean square acceleration (awrms) for both training and test stages. AI has revolutionized the mining industry, bringing digitization and automation to the forefront. The predictive model presented here for WBV-related health risks is a powerful tool for mine safety engineering. By harnessing machine learning techniques, it improves risk assessment and enables targeted interventions, improving the quality of life of the mining workforce.

Amit Sharma, Bibhuti Bhusan Mandal, Monika Tewari

Numerical Modelling and Applications

Frontmatter
FLAC 3D Modeling for Excavation Activity in an Underground Marble Quarry in Ambaji (Gujarat - India)

Dimension stones have been exploited in almost all parts of the world for millennia. In the 20th century, stricter legislation has sometimes limited opencast quarrying with the result that, under favorable geological conditions, underground mining is adopted. The latter gains in popularity also due to environmental and land use positive issues. In the case of the Ambaji marble quarry, the second option was a necessity to augment marble production and to exploit large parts of the concealed marble deposit which, otherwise in case of quarrying, would have required huge investments for the removal of large quantities of useless cap rock with inevitable environmental damage.This study presents the approach for assessing the stability of underground chambers and pillars through numerical modeling of the marble deposit at Ambaji’s Zarivav quarry. To analyze its long-term stability, a detailed investigation was conducted to draw the present and future geometry, the rock mass characterization, and to assess the surrounding rock behaviour. Based on field survey and laboratory tests, numerical simulations were performed using the finite difference code FLAC3D. The geomechanical analysis and the exploitation techniques applied to Zarivav quarry can be a path-finder for other similar projects in mining industry.

Piero Bettini, Vidan Ilic
An Investigation on Optimal and Safe Design of Highwall Mining Panel Beneath Jointed Overburden Strata Using Discrete Element Modelling

When the mine boundary is reached during surface mining operations, and conventional opencast mining becomes impractical to proceed further, a significant amount of coal reserve is left trapped under open-pit highwall. To overcome these challenges, the Highwall mining method can be seen as a viable option to increase coal production from previously operated opencast mines by extracting the trapped coal reserves and exploit thin seams that were left unmined due to economic limitations. In highwall mining, the safety and stability of a Highwall panel rely heavily on scientifically-designed dimensions of openings, web pillars, and barrier pillars. Pillar dimensions are determined using empirical formulae suggested by various researchers. However, designing highwall mining panels becomes challenging in cases where there is a presence of jointed rock mass in the overlying overburden strata, making it difficult to rely on available empirical formulas. In this study, a 3D discrete element model of a Highwall panel has been prepared incorporating the presence of jointed overburden rock mass using 3DEC™ software. Factor of safety for the overall highwall structure was determined based on observations of different combinations of web pillars, barrier pillars, and opening size. Based on which optimal and safe design of Highwall mining panel has been recommended.

Siddhartha Roy, Hemant Agrawal
Numerical Modeling of Split-Set Friction Bolt

Other than grouted type of rock bolts, such as resin or cement encapsulated bolts, friction type of bolts are also getting popular in mining and other underground structures. A split-set friction bolt is one such rock reinforcement. They are cheaper and quicker to install as compared to the grouted type bolts and can provide reinforcement to the rock mass immediately after installation. They are used mostly as secondary rock mass reinforcement, such as for pinning a wire mesh prior to resin encapsulated bolting. However, in very weak rock mass and re-developed roadways through cemented backfills, grouted bolts are difficult to install and therefore split-sets offer a better primary ground support. Basically, a split-set friction bolt is a long hollow ‘C’ shaped cylinder which is inserted into an undersized hole. The frictional force generated due to the undersized hole create a pressure radially due to which the bolt fits into the rock. In this study a numerical modelling procedure is developed to simulate the mechanism of the split-set. The model is tested by simulating its ultimate pull-out load for different lengths and diameter of the split-set, which is indirectly a measure of its load bearing capacity. In this study pull-out load of different lengths and diameters is investigated using elasto-plastic numerical analysis in a finite difference software viz. FLAC3D. The trends obtained from numerical modelling are validated using field tests.

Sai Rohith Samala, John Loui Porathur, Ayan Giri, Vinod Kumar Jagapthal

Mine Waste Management

Frontmatter
Utilization of Fly-Ash in the Backfilling of Void in Underground Mines

Coal-fired thermal power plants worldwide are encountering significant challenges in handling and disposing of the ash generated during the combustion process. The problem is further exacerbated by the high ash content (30–52%) present in Indian coal. Thermal power plants face major concerns regarding the safe disposal of coal ash and the need for large storage areas. Consequently, efforts have been made to find alternative uses for the ash, rather than simply dumping it in nearby ash ponds. One promising approach involves utilizing underground mine voids to accommodate the bulk of the fly ash. Underground mine spaces have the greatest potential for storing fly ash in large quantities compared to other possible applications. The process involves using filling materials to reinforce the surrounding rock and provide support to the overlying strata, thereby reducing surface subsidence. This paper presents a study conducted in this context, focusing on the bulk utilization of fly ash in backfilling applications. The research aimed to find viable solutions for effectively utilizing fly ash, thereby addressing the challenges faced by coal-based thermal power plants in managing and disposing of this by-product. This innovative approach presents an encouraging solution for sustainable mining practices and minimizing the environmental impact associated with coal extraction.

Vivek Kumar Kashi, Atma Ram Sahu, Roshan Kumar
Underground Mine Backfilling Transition in Sukinda, Odisha: Present and Future

Mine back filling is an integral part of overall mining operation. This paper highlights the progress of underground mine back filling practices in Sukinda region, Odisha. Initially underground stope backfilling started with sand based cemented hydraulic backfilling. Slowly, the transition to other backfill material has also being done. Mine overburden, bottom ash and slag are few of the options of alternate backfill materials that can be used for underground stope filling. This study elaborates the results of strength development and water drainage characteristics of cemented hydraulic backfill prepared with sand /bottom ash. This study also highlights a future roadmap towards application of modern day paste backfill technology in underground mines of Sukinda region, Odisha.

Santosh Kumar Behera, Prashant Singh, Kanhaiya Mishra, Phanil Kumar Mandal, Sujit Kumar Mandal, Ritesh Kumar

Coal Gasification and Coal Bed Methane

Frontmatter
Gasification of High-Ash Indian Coal and Agro-Industry Biomass Waste in Oxy-Blown Bubbling Pressurized Fluidized Bed Gasifier

India has great potential to utilize high-ash Indian coal and agro-industry-based biomass towards clean fuel technology via the gasification route which is energy efficient and environment friendly. Due to the limitation of handling low-ash coal (ash% < 30 wt.%) in all the mature gasifiers worldwide, the development of fluidized bed gasification technology is needed for the judicious utilization of high-ash Indian coal and agro-industry biomass waste to strengthen“Methanol & Hydrogen Economy” and “Net Zero Emission”.In this study, the developed BPFBG has demonstrated input fuel power of 60–80 KWth and 15–25 KWth for high-ash Indian coal and rice husk respectively in the presence of gasifying agents such as the mixture of pure oxygen-steam, at lower pressure and 900–1000 ℃ temperature. At optimal high-ash Indian coal gasification operational condition of ER of 0.32 along with steam-to-coal ratio of 0.70 and rice husk gasification operational condition of ER of 0.30 along with steam-to-rice husk ratio of 0.40, produced syngas composition was H2:32.64, CO:22.83, CO2:24.54, CH4:5.87(v/v%) and H2:9.45, CO:22.14, CO2:40.12,CH4:7.01(v/v%) respectively. Further, this development would give input data for the establishment of a Demo-scale facility based on Fluidized Bed Gasification Technology in India.

Rupesh Kumar Singh, Nilesh D. Dhaigude, Arti Sahu, Vishal Chauhan, Gajanan Sahu, Pavan Kumar Gupta, Sujan Saha, Prakash D. Chavan
Syngas Cleaning Technologies in Gasification Process for Downstream Applications

Syngas (CO and H2) are cleaner and environmental friendly fuel as compare to fossil fuels. Generation of syngas using the availability of vast variety of feedstock (coal, biomass, natural gas, municipal solid waste etc.) make it lucrative option as an alternative to substitute for the conventional liquid fuels and other chemicals. In the industry, the word “syngas” is frequently used to refer the product gas from the gasification and reforming process from solid (coal, biomass, municipal waste, petcoke) and gaseous carbonaceous (natural gas) feedstocks respectively. During gasification process various elements like sulphur, nitrogen, halogen and alkali metals present in carbonaceous feedstock get converted to contaminants and generally referred as “impurity”. The concentrations of these impurities are heterogeneous and depend strongly on the carbon source, and gasification operating parameter (e.g. pressure, temperature, residence time, types of gasifier). Those impurities can lower the activity of almost any type of catalytic reactions, so it is essential to remove them to meet the downstream process specifications. The presence of these pollutants in syngas causes a variety of technical and operational challenges, including equipment corrosion by hydrogen sulphide, and catalyst deactivation (tar, hydrogen sulphide, ammonia, Hydrogen chloride, and trace metals). Syngas cleaning methods are comprehensively reviewed in the present paper.

Pavan K. Gupta, Sudipta Datta, Shiva K. Saw, Shweta Kumari, Gajanan Sahu, Rupesh K. Singh, Vishal Chauhan, Prakash D. Chavan
Refracturing in CBM Wells: A Case Study

Essar Oil and Gas Exploration and Production Limited (EOGEPL), located in Raniganj under Paschim Bardhhaman district of West Bengal, India is spread over a 500 square kilometres area in the prolific Damodar Valley Basin with thick Permo-Carboniferous Gondwana coal seams. Nearly 350 wells have been operating since last 10 years. From the production data of more than 350 wells, it has been observed that some of the wells have been underperforming while compared with their offset wells. It has also been observed that the production from some of the wells have declined over a period of time. EOGEPL opted for refracturing as a stimulation technique to increase the production from such wells.In inefficient initial fracturing category, 14 wells were selected for refracturing and it resulted to increase in gas production from 18,004 Standard Cubic Meters Per Day (SCMD) to 28,891 SCMD. In next category where stimulation bypass was suspected, 13 wells were selected in which gas production increased from 986 SCMD to 4,167 SCMD. In last category of wells where formation damage was suspected and due to which substantial decrease in production was observed, 11 wells were selected in which production decreased from 18,165 SCMD to 14,058 SCMD.

Anjani Kumar, G. P. Karmakar

Mine Health Safety and Environment

Frontmatter
Reliable Intrinsically Safe Circuit Design Specifications for Oil Fields and Coal Mines

Electrical equipment installed in coal mines or oil fields must fulfil the requirements of anti-explosive or explosion-proof. The electrical sparks are frequent due to abnormal operations and these sparks may act as an ignition source for the explosive atmosphere on the field. Intrinsically safe circuits are the safest circuits that are being used in explosive hazardous environments. Since a regular advancement in the circuit is being done. Due to this, circuits are becoming complex day by day. Increasing complexity requires detailed attention while designing the printed circuit board layout. The circuitry designs of these apparatus have to meet the performance and design requirements as per the standard IS/IEC 60079-11. Most of the circuits consist of non-linear circuit components and energy storage components. The presence of these components makes the work difficult to use minimum ignition voltage current curves directly. Reliability in safety plays an important role in getting the continuous desired performance of any electrical equipment safely which is discussed in this paper. Simulation for the proposed issue was also carried out using MATLAB. The simulation results align with the output of spark test apparatus. This shows the reasonableness of the proposed reliability study.

Amit Kumar, Anup Kumar, Rakesh Kumar Mishra, Manoj Kumar Vishwakarma, Bishwajit Modak, Amar Kumar Singh, Awanindra Pratap Singh
Microbial and Biosorbent-Mediated Hexavalent Chromium Removal from the Tailing Waters Released from Chromite Mines

Chromium (chromite) mining operations can generate specific problems related to tailing water. There is a serious threat to human health and ecosystems when chromium-contaminated tailing water is released into the environment. Reduced biodiversity and long-term ecological impact may result from these tailing water. Hexavalent chromium (Cr (VI)) being the most toxic form of chromium than Cr (III), causes serious illnesses like ulceration, irritation of the skin, lung cancer, kidney necrosis, asthma, and allergic reactions. In the present study, a total of ten Cr (VI)-reducing bacteria were isolated from these mine tailing water samples, out of which two strains exhibited a maximum tolerable concentration of 200 mg/L. The maximum reduction efficiency was found to be 40.3% for an initial Cr (VI) concentration of 50 mg/L. However, due to the lower reduction efficiency of the bacterial biomass (i.e., in-situ bioremediation), the present study also investigated the role of biosorbent using different plant-derived biomasses for the removal of Cr (VI) from the aqueous environment. The plant-derived biomasses proved to be efficient for the removal of 86.24% for an initial Cr (VI) concentration of 20 mg/L. The observations from two different isotherm models and kinetic modeling for these biosorption studies support the adsorption processes as well as indicate the endothermic and spontaneous nature of the processes. Hence, plant-derived biosorbents could be employed as an efficient, cost-effective, and eco-friendly alternative for the removal of Cr (VI) from the tailing water of chromite mines.

Puja Dokania, Sourav Maity, Tapaswini Nayak, Shingam Jayantu, Angana Sarkar
The Case for ISO 23875:2021 W/Amendment 1: 2022 as the Path to Hemm Protection from Respirable Crystalline Silica (Rcs)

Respirable Crystalline Silica (RCS) is a problem prevalent in the mining industry that impacts the long-term health of the workforce across a wide range of work processes and tasks. Significant research has been conducted over time both to understand the scope of the problem in RCS-exposed environments and to engineer effective solutions to protect workers. The U.S. based National Institute for Occupational Safety and Health (NIOSH) began research into the efficacy of operator enclosures as an engineering control in the 1990’s. Research done in conjunction with several industry partners, including Sy-Klone International, has resulted in multiple projects, publications, and ultimately product solutions. ISO 23875 Mining - Operator enclosures - Air quality control systems and air quality performance testing was developed by ISO Technical Committee 82 – Mining and was published in February 2021. ISO 23875 provides a comprehensive focus on controlling dust concentrations, CO2 levels, and cab pressure over the lifecycle of the operator enclosure. Additionally, Annex B gives guidance on the operational integration of the cab into the site occupational health and safety management system. The standard’s comprehensive nature and enthusiastic stakeholder adoption make it a consensus driven regulatory tool to protect machine operators working in enclosed cabs.Respirable Crystalline Silica (RCS) is a problem prevalent in the mining industry that impacts the long-term health of the workforce across a wide range of work processes and tasks. Significant research has been conducted over time both to understand the scope of the problem in RCS-exposed environments and to engineer effective solutions to protect workers.The U.S.-based National Institute for Occupational Safety and Health (NIOSH) began research into the efficacy of operator enclosures as an engineering control in the 1990’s. Research done in conjunction with several industry partners, including Sy-Klone International, has resulted in multiple projects, publications, and ultimately product solutions, some of which are still ongoing. In 2009, Sy-Klone International produced its first generation of cab air quality products incorporating high efficiency filtration tailored to human respiration. This product was utilized in research on a sandstone cutting machine by the Queensland Australia Government in 2009. This study, known as RESPA™ Trial 2009 Occupational hygiene monitoring for airborne particulate matter and respirable crystalline silica (RCS) inside an excavator cabin – before and after fitting a pre-cleaner, filter and pressurization unit, was published in 2010 by the Queensland Government. The study demonstrated the value of the air quality control system in reducing RCS exposures when fitted with effective engineering controls.NIOSH and Sy-Klone International’s joint research are the foundation for operator enclosure air quality engineering controls in the NIOSH Dust Control Handbook. The International Society of Environmental Enclosure Engineers (ISEEE) advanced the science by introducing a robust field monitoring system that allowed for operator enclosures to be evaluated in real world conditions, over a work shift. With this research and field experience, ISEEE developed a course on operator enclosure air quality engineering in 2014, much of which became the basis and a catalyst for the development of ISO 23875.ISO 23875 Mining - Operator enclosures - Air quality control systems and air quality performance testing was developed by ISO Technical Committee 82 – Mining and was published in February 2021. Lehigh Hanson, part of the Heidelberg Cement Group, sponsored a pilot installation utilizing ISO 23875 in 2021, to assess its effectiveness in granite quarry operations. The study by Lehigh Hanson was submitted to NIOSH as evidence of industry’s proactivity in addressing silica exposure at their aggregate quarry. The project won the NIOSH Mine Health and Safety Technology award in 2021.While many studies have been completed as pilots for ISO 23875 and can be seen on the ISEEE website, one of particular interest was performed by an international mining company in Canada. The yearlong study was to determine the specific work being performed when RCS overexposure was encountered. Their study found that the greatest exposure took place within operator enclosures on machines or transport vehicles which move RCS-containing materials or travel through RCS-contaminated environments. Of note were the crew buses responsible for bringing miners to their respective workstations, bull dozers moving material, light trucks working in the pit, and office workers in the lab where the material was crushed for qualitative analysis. The highest exposures, in terms of degree and as a percentage of total exposures, took place in operator enclosures. The result of this study was the decision to implement ISO 23875 to address operator enclosure air quality. This study was presented at the American Industrial Hygiene Association (AIHA) mining working group meeting in April of 2022.The American Industrial Hygiene Association (AIHA) mining working group participated in the development of ISO 23875 Mining - Operator enclosures - Air quality control systems and air quality performance testing. The article can be viewed at https://synergist.aiha.org/20210607-standard-to-help-protect-miners .Worker health is not a primary consideration in general business for several reasons: (1) While there is near universal empathy for stricken workers, there is no universal agreement on where fault lies for the illness. (2) A prevailing sentiment, regarding workers taking personal responsibility for their hygiene practices, places an unrealistic expectation on their ability to protect themselves. (3) Investment in worker health is perceived as non-essential when workers move from job to job frequently and/or are abundantly available to the employer. Accountability for worker health is not possible when workers do not stay in a job long enough to prove that their health condition was caused by a specific job or employment environment. (4) The cost of implementing protective measures, if not borne by everyone in a competitive industry, creates an imbalance, which leads to price advantages for companies that choose not to invest in protective measures. (5) Limited social/community awareness exists. While massive amounts of RCS are released in public areas during road construction, residential pool construction, benchtop cutting, in front of residences during the installation process of brick cutting, concrete removal projects etc., its risks are not widely known. There is little public outcry and no reporting mechanism for RCS releases. Leveling the playing field through government intervention compels all businesses to invest in worker protection without a competitive disadvantage. Government can also educate workers and workplaces, bring research-based solutions to industry, strongly contribute to more positive long-term public health outcomes, as well as create social awareness and reporting mechanisms.Government has a primary responsibility to protect its citizens. This responsibility cannot be abdicated to private enterprise, whose goals may not align with the public good.One solution specific to operator enclosures is the inclusion/adoption of ISO 23875 with Amendment 1 in health legislation/regulation, as a readily available, practical, cost-effective, and consistent methodology to control RCS exposure in operator enclosures at all applicable types of RCS-impacted job sites.We would recommend the inclusion of ISO 23875 with Amendment 1 as part of the regulatory regimen to control RCS exposure. The standard’s comprehensive nature and enthusiastic stakeholder adoption make it a logical path forward to protect machine operators working in enclosed cabs. The bibliography to the standard is included to assist in sourcing reputable documents which support/answer many of the questions asked about the problems of and solutions to RCS overexposure in environmentally controlled operator enclosures. The mining industry in India may work to get consensus on a solution, which can be made universal within India, with the help of the Indian Government. There is widespread support for ISO 23875 among the Industrial Hygiene community globally.Global mining companies, such as Rio Tinto, have adopted the standard as part of their self-regulation efforts. ISO 23875 represents both state-of-the-art and best practices for the control of respirable particulate in operator enclosures and provides a consensus-driven engineered solution against RCS exposure at a cost that is as low as reasonably practicable.Worker overexposure is the result of inadequate protections. When working openly in an RCS-saturated environment, workers should use properly fitted and tested PPE in good repair on a clean-shaven face. However, workers can develop a false sense of protection when working in an environmentally controlled enclosure, like a control room or operator cabin on a piece of heavy equipment.The international mining community has been seeking to address the universal problem of operator protection while operating a machine in an environmentally controlled enclosure. In the absence of a standard, previously, the industry was self-regulating based upon local RCS regulations. The result was a myriad of approaches to proper cab engineering. However, now that ISO 23875 with Amendment 1 is in place, it allows for a common framework for control and enforcement of air quality in an operator enclosure. Territories and countries around the world (e.g., EU, Australia) are adopting ISO 23875 with Amendment 1 and using it as a blueprint for the regulation and enforcement of RCS exposure in enclosures.The introduction and scope of the ISO 23875 standard is included below for a more detailed overview and the full document is available from ISO at https://www.iso.org/standard/77249.html . INTERNATIONAL STANDARD ISO 23875. FIRST EDITION 2021–02. Mining—Air quality control systems for operator enclosures—Performance requirements and test methods.

Jeffrey L. Moredock, Biswajit Dutta, Ankit Chatterjee
Enabling Net Zero Industrial Targets Through Decarbonizing Lubricant Life-Cycle

Lubricants play an important role in keeping the machinery running smoothly and efficiently. The demands for lubricants are increasing and eventually impacting the environment. There is a need to balance the increased demand with the impact of lubricants on the environment. As the world is facing a climate emergency, industries are urged to decarbonize. With innovative technologies, industries can lower the carbon emissions from their operations and reduce their carbon footprints. The technologies like Lubricant Reconditioning Systems which helps in increasing the oil’s life and reliability ultimately leading to the lesser oil replacement costs and new oil purchase. What people are doing now is taking materials from the earth, making products from them, and giving them back to the environment in the form of waste. The ‘Circular Economy’ tackles global challenges like these while addressing important social needs. Through Oil Reclamation, the oil is rescued from normal degradation; it involves removing the contaminants from the oil and restoring it to good health. This offers many benefits like increased machine reliability, cost savings, saving of time on oil change-outs, decreased oil disposal costs, and reduced environmental impacts.

Anshuman Agrawal

Critical Minerals

Frontmatter
The Impact of Recent Geopolitical Events on Supply of Critical Minerals for an Early GET

The most important step in fighting the climate change menace is to have an early switch over to a decarbonized global economy. Fossil fuels currently supply about 80% of the world's energy needs and hopefully, a major part of the same can be replaced by energy from renewables within a few decades. It is a gigantic task complicated by the variety of conditions and priorities in different countries. An adequate supply of some specialized minerals is essential to usher in the Green Energy Transition (GET). The accelerated induction of electrical vehicles in many countries in the last two years has necessitated a relook at the availability of battery metals. The R&D efforts for improving battery technology are going on in full swing. However, two recent world events, namely the Covid-19 pandemic and the Russia-Ukraine war, have adversely affected the world’s progress towards an early GET. The latter event especially, has caused the major economies of the world to pay greater attention to energy security and assured supply chain arrangement for critical minerals. The paper examines the issue of the availability of minerals for GET in the coming decades from the global as well as the Indian perspective.

S. P. Banerjee
Design of Operators’ Cabins for Mineral Processing Plants Using Specially Fabricated Acoustic Material With Simple Expansion Chamber Structure

Mineral processing plant operators are frequently exposed to noise levels that can reach up to 100 dB(A). This research aims to find appropriate acoustic materials for the construction of cabins that can protect the operators by reducing noise levels by at least 15 dB(A) in the specific frequency range of 0.5–5 kHz, as the human ear is more sensitive to these frequencies. 3D printed material made from Ultraviolet (UV) cured standard resin with an internal Simple Expansion Chamber (SEC) structure was selected for the design. The ratio of the length of SEC to the total thickness of samples varies from 80%–20% keeping the thickness of the sample constant to investigate the optimum length of SEC. Acoustic properties like Sound Absorption Coefficient (SAC) and Sound Transmission Loss (STL) were measured using the Impedance Tube Apparatus. A maximum SAC of 98% was observed at 3.075 kHz when the sample having a ratio of the length of SEC to the thickness of the sample is 80%. The peak SAC decreases when the length of SEC is reduced from 8–2 mm. STL increases when the length of SEC decreases from 8–2 mm. Based on our findings, it is evident that our designs hold significant promise for constructing operator's cabins, offering effective attenuation of at least 20 dB within the tested frequency range of 0.5–6.3 kHz.

Nihar Ranjan Sahu, Bibhuti Bhusan Mandal

Mine Fire and Ventilation

Frontmatter
Design of an Effective Ventilation System for Deep Underground Coal Mines Affected by Spontaneous Heating and Fire Using Double Booster Fans – A Practical Approach

Deep underground coal mines in India are particularly vulnerable to spontaneous heating/fire accidents, which put miners’ safety and mines at risk. Spontaneous heating leading to fire and explosion results in substantial financial losses for the mining industry. This study examines practical methods for the prevention of spontaneous heating/fire in deep underground coal mines of the Jharia coalfield using ventilation control techniques. It identifies the major factors impacting the design of a ventilation system for the prevention of spontaneous heating/ fires in one of the deep underground coal mines of the Jharia Coalfield. An attempt has been made for the prevention of spontaneous heating/fire to improve the workplace environment by incorporating a double booster fan into the ventilation circuit. The computer simulation study reveals a viable solution involving the use of a double booster fan to produce the requisite air quantity. The finding of the study is successfully implemented at the 2-pit Jamadoba colliery of Tata Steel Limited (TSL).

Debashish Mishra, N. K. Mohalik, D. P. Mishra, S. K. Ray, Asfar M. Khan, J. K. Pandey
Assessment and Control of Concealed Fire in Underground Coal Mine: A Case Study

Coal, the most used fossil fuel, is a gift of nature to mankind. However, the Phenomenon of auto oxidation / fire in this fossils fuel has a long history on international magnitude in the destruction of valuable natural resources and dominantly contributes towards adverse impact on environment by liberating obnoxious and toxic gases. The fire in underground coal mines creates hazardous environment for the mining operation and endangers the life of miners. It is also a major problem for the Indian coal mining industry and exists since beginning of the mining. A huge amount of the precious coal reserves of different coalfields are blocked due to existence of fire and thus cannot be extracted without extinguishing it. In the case of concealed underground coal mine fire, without locating its exact location and root cause, its control effort may be futile.In the present paper, a case study has been discussed for assessment of concealed underground coal mine fire locations and its major cause of initiations. Furthermore, the methodologies adopted for control this menace to overcome the safety threats of mines are also presented.

Jitendra Pandey, A. Khalkho, S. K. Ray, Aditya Kumar, J. K. Pandey

Explosive and Blasting

Frontmatter
Strategic Planning and Guidelines to Control Dust and Post-Detonation Fumes Arising Due to Blasting in Opencast Coal Mines

To exploit coal from opencast mines, commercial explosives, in large quantities, are used for blasting of overburden rock. The increased use of commercial explosives creates a lot of problems due to the sprawl of urbanization and man’s increased sensitivity to blasting that ultimately necessitates cost-effective and safe rock excavation techniques. It is aimed at exploiting coal safely and productively from opencast mines without any health risk to the mine workers and people residing in the vicinity of the mine.The objective of the paper is to develop a strategic planning, categorization of different subsystem parameters and framing of guidelines to control dust and post-detonation fumes arising due to blasting which would directly help the mine management to control such unwarranted hazards by putting them below the regulatory safe levels. It would also help in generating a huge amount of multilateral data for formulating new sets of guidelines for the mining industry. Non-compliance of regulatory guidelines would otherwise lead to silicosis and other respiratory diseases to mine workers and neighbouring residents.

Pijush Pal Roy
The Influential Role of Confinement, Charge Factor and Segmentation of Explosive Charge in a Blasting Round: A Perspective for the Blasting-Induced Ground Vibration Compliance

This paper focuses on evaluating the effects of confinement, charge factor and segmentation of holes in a blast round on blast-induced ground vibrations in a mine. The study involved conducting a series of experiments with different drillhole diameters and modifying design parameters. The results indicated that the initial blast designs were not optimised, resulting in to generation of higher magnitudes of ground vibrations. Based on the vibration data recorded, regression analysis was carried out to establish a best-fit relationship between the scaled distance and vibration. On the basis of the threshold values of peak particle velocity prescribed by the DGMS, the permissible maximum charge per delay at specific distances were determined. The permissible charge values were not workable and matching with the mine productivity. The subsequent experimental blast with a smaller drill hole diameter also did not significantly reduce the magnitudes of ground vibrations. However, the experiments conducted with reduced confinement conditions with less number of holes and optimized charge factors resulted in a notable reduction in the ground vibration magnitudes. An innovative technique of segmentation of total holes in a blasting round using electronic detonators demonstrated a significant decrease in vibration magnitudes with the potential of increased productivity. The findings of the study emphasize the importance of re-assessing the blast design parameters and charging patterns to mitigate ground vibrations and optimize the blast outcomes in mining operations.

Narayan K. Bhagat, Rakesh K. Singh, P. Hembram, C. Sawmliana, A. K. Mishra
Innovative Blast Design for Reduction of Boulder Generation in Opencast Excavations

The overall economy in mining operation is being affected by rock fragmentation. The size of fragments affects the productivity of excavators, crushers and mills. The generation of oversize boulders additionally need secondary breakage mechanism. So, the reduction of boulder generation during the bench blasting is one of the prime objectives of a blast designer. The scientific methods may be utilised to reduce the boulder generation. The geological and geotechnical parameters are assessed in this process. The charging pattern, delay timing and free face condition primarily affects the resulting blast induced fragmentation. In this paper, an innovative blast design methods used at Kanchan opencast coal mine to reduce the generation of oversize boulders, has been discussed. The sandstone rock at this mine exhibited plastic nature. This method has been designed by assessment of the reason for the boulder generation. The assessment suggested that the blasting in such rocks needed explosive energy throughout the column. The boulder generation was seen mostly from the stemming portion. Accordingly, the methods with pocket charging and satellite hole drilling were devised. The delay patterns were optimised to improve the movement of the muckpile. The devised blasting methods have addressed the issues of the boulder generation.

Vivek K. Himanshu, Ashish K. Vishwakarma, C. Sawmliana, R. S. Yadav, M. P. Roy, A. K. Mishra
Evaluation and Quantification of Textural Properties of a Rock and its Impact on Blast Induced Ground Vibrations

Main factors which influence the microcracking process are mineralogy, fabric and microstructures present in a rock. Crack initiation and propagation started during the dynamic loading. The objective of this paper is to investigate, how the mineralogy of rock affects the crack initiation and propagation process and transmission of induced ground vibration during the blasting of rock mass. The study was conducted in rocks containing biotite, muscovite, amphibolite, quartz, schist and gneiss. Physico-mechanical property of rock depends on the Textural coefficient which was determined to evaluate the physico-mechanical properties of the rock under study. The micro textural properties of rocks are important to understand the strength and failure behavior of the rock. The samples of metasedimentary rock were collected and their petrophysical properties and textural coefficient were determined using thin section slides and Scanning Electron Microscope (SEM). The pattern of cracks and their initiations were studied to identify the behavior of rock under induced stress conditions as well as its impact on ground vibration propagation. Crack initiation and propagation pattern studied by the digital image analysis method and measured the length and aperture of the crack. Thin section slides used to know the mineralogical composition of the rock. The study includes the petrographical and mechanical characteristics of metasedimentary rocks, various laboratory tests for mechanical characteristics and results, different types and features of explosives, variables that affect blast design, and the effects of blasting on rock mass. An empirical relation between all these parameters to know the actual behavior of rocks during the dynamic loading condition was developed to quantify the impact of microtextural properties of a rock.

Vivek Priyadarshi, Ranjit K. Paswan, Vishal Sagar Rana, Sourabh Kushwaha, M. P. Roy
Controlled Blasting Within Danger Zone of 500 M From Dwelling Vis-À-Vis Production Enhancement-Problem and Challenges

Controlled blasting has become imperative in many Indian open cast mines as the workings benches are within/approaching the danger zone of 500 m. Accordingly the blasting impacts in the form of ground vibration, flyrock and air overpressure/noise should be controlled within the permissible limits for the safety of nearby dwellings. Flyrock can be controlled by proper blast design and application of effective muffling arrangements. Ground vibration can also be limited within the permissible limits by applying various techniques for various structures as per DGMS Circular No. 07 of 1997. However, an undue reduction in progress is often observed due to inevitable reduction in blasting geometry during controlled blasting operations. Hence, it is need of hour to pace up the production, particularly for the removal of overburden in coal mines to attain the targeted production. This paper discusses the different techniques used for reduction of blasting impacts at different opencast mines. Nevertheless, it also highlights the problems and challenges faced for maintaining the production rate within 500 m from the dwellings.

Aditya Rana, Saikat Banerjee, Arvind Kumar, Atul Singh, Chhangte Sawmliana
A Comprehensive Analysis of the In-Plane and Out-of-Plane Response of a Masonry Wall Under Blast Loading Conditions in the Vicinity of Coal Mines

Masonry structures are widely used in construction practices worldwide, but they can still suffer severe damage when subjected to blast loadings. This study aims to investigate the impact of blasting activities, a critical component of the mining industry, on nearby masonry structures. Specifically, it focuses on two commonly employed types of brick masonry walls: English bond and Stretcher bond. The research utilizes ABAQUS CAE to develop models and conduct explicit analyses to assess the response of these walls. To accurately capture the behaviour of the brick materials, a simplified micro modeling technique is employed, which incorporates the Drucker-Prager hardening criteria to account for the plastic behaviour of the bricks and mortar. Geophone sensors were used to record blast data at the foundation level of residential structures in close proximity to a coal mine (recorded ppv ranging from 7 mm/sec–30 mm/sec). A comparative analysis of the in-plane (IP) and out-of-plane (OOP) behaviour was performed, aiming to evaluate the impact of the structures' orientation relative to the blast direction. The study observed that in addition to the generally considered in-plane (IP) conditions, the out-of-plane (OOP) loadings generated due to blasting can also endanger the safety of structures and occupants. Therefore, this work provides a helpful reference for the design of blast-resistant brick masonry walls and suggests measures to safeguard them against damage caused by both in-plane and out-of-plane loading conditions.

Monika Tewari, Bibhuti Bhusan Mandal, Amit Sharma
Backmatter
Metadaten
Titel
Proceedings of the 10th Asian Mining Congress 2023
herausgegeben von
Amalendu Sinha
Bhabesh Chandra Sarkar
Prabhat Kumar Mandal
Copyright-Jahr
2023
Electronic ISBN
978-3-031-46966-4
Print ISBN
978-3-031-46965-7
DOI
https://doi.org/10.1007/978-3-031-46966-4