Physical Sciences and Mathematics Commons^™

Can Corporate Sustainability Performance (Csp) Overcome Indonesia's Corporate Debt Problems?, Johnson Ferry Febrian, Nora Sri Hendriyeni

Jurnal Akuntansi dan Keuangan Indonesia

Based on IMF publications (2022), Indonesian companies have a risky debt level that may cause bankruptcy, so companies are required to make leverage adjustments to return the debt to its optimal level. In recent years, corporate sustainability performance (CSP) practices have been proven to improve performance and overcome financial problems such as debt by integrating sustainability aspects into business processes. Based on stakeholder theory and trade-off theory, this study aims to examine the effect of CSP on leverage adjustment and the role of competitive advantage, equity mispricing, profitability, and firm size in moderating this relationship. This study used a sample …

Critical Raw Material In Mineral Elements Found In Fly Ashes From The Czech Republic Power Plant, Agnieszka Klupa

Journal of Sustainable Mining

The economic development of EU countries is limited due to limited access to a number of mineral raw materials, which necessitates actions aimed at securing the supply of CRM. For this reason, CRMs constitute elements of particular importance for the EU. The aim of the study was to assess the content of CRMs as a potential source of REY in fly ash resulting from the coal combustion in one of the power plants in the Czech Republic. In the tested ash the main phases are: glassy phase, mullite and quartz. The chemical composition of the tested fly ashes showed dominance …

Induced Oxidation Effects On Physical And Mechanical Properties Of Lignite From Tempoku, Hokkaido, Japan For Sustainable Mining Via Subsurface Cultivation And Gasification Method, Akm Badrul Alam, Noritaka Aramaki, Shuji Tamamura, Akio Ueno, Takuma Murakami, Yoshiaki Fujii, Katsuhiko Kaneko

Journal of Sustainable Mining

The lignite resource has been under consideration for the subsurface cultivation and gasification (SCG) method to produce biomethane from lignite in Hokkaido, Japan. The primary phase of the method entails initiating the oxidative transformation of lignite using an H₂O₂ solution, resulting in the formation of dissolved organic carbon (DOC), a pivotal component. To examine the effects of induced oxidation on lignite's mechanical properties, artificial oxidation tests were conducted to form DOC. While there was a slight decrease in P-wave velocity and density, the uniaxial compression and indirect tensile strengths, as well as stiffness, did not decrease. These …

A Biocompatible Hybrid Approach For The Selection Of Gas Drainage Methods In Coal Mines Based On The Best-Worst Method And Analytic Network Process, Amir Jafarpour, Mehdi Najafi, Ali Dabagh

Journal of Sustainable Mining

Methane drainage is one of the main steps in underground coal mining projects. The operation of methane extraction from coal mines/seams is important from the safety, economic, and technical points of view. Selecting the appropriate method for methane drainage is very difficult, and if the method is not chosen correctly, it will lead to environmental problems. The relationship between different influencing factors, parameters, and methods (and how they affect) is significant in choosing the method of gas drainage. In the current study, a hybrid algorithm is presented based on an Analytic Network Process (ANP) and a method based on the …

Dispersion Of Artificial Tracers In Ventilated Caves, Claudio Pastore, Eric Weber, Frédéric Doumenc, Pierre-Yves Jeannin, Marc Lütscher

International Journal of Speleology

Artificial CO₂ was used as a tracer along ventilated karst conduits to infer airflow and investigate tracer dispersion. In the karst vadose zone, cave ventilation is an efficient mode of transport for heat, gases and aerosols and thus drives the spatial distribution of airborne particles. Modelling this airborne transport requires geometrical and physical parameters of the conduit system, including the cross-sectional areas, the airflow and average air speed, as well as the longitudinal dispersion coefficient which describes the spreading of a solute. Four gauging tests were carried out in one mine (artificial conduit) and two ventilated caves (natural conduits). …

Analysis Of The Key Performance Indicators Between Lithologies On Mine To Crusher, Janine Figueiredo, Vidal Torres, Rodolfo Cruz, Douglas Moreira

Journal of Sustainable Mining

The evolution of the mineral economy requires greater technological developments to find a better use of resources and reserves through the relationships between the characteristics of the rocks and the need to enable the entire mining enterprise. This study focuses on the development of new rock blasting technologies that result in a more optimized fragmentation according to the lithology in the feed of the primary crusher. This methodology is known as Mine to Crusher, through which it becomes possible to minimize costs in the future prospecting of the mine and maximize productivity. For this methodology to be developed, it was …

The Role Of Greenways In Achieving Urban Sustainability For Cities Accordance With The Sustainable Development Goals 2030, Walaa Ahmed Nour Prof, Aya Abdelazim Abdeen, Lobna Agha Prof

Journal of Engineering Research

The concept of "greenways" emerged to achieve sustainable development in urban areas and to address natural disasters resulting from climate change. This research paper aims to study the role of greenways in achieving urban sustainability and their facilitation in achieving the Sustainable Development Goals for 2030. The paper expounds on the idea and origin of greenways, their benefits, and analyzes some global examples. Furthermore, it categorizes the indicators of greenway design into two types: those with a positive impact and those without an impact on sustainable development goals. Using standardized tools, the relationship between each indicator and sustainable development goals …

Desalination As A Source Of Freshwater, Jacob Pensky

Best Integrated Writing

Jacob Pensky's article deals with technology we use to make saltwater drinkable. Drought-stricken coastal communities need desalination plants, especially as Earth's climate warms, but they are expensive and energy-intensive. This article describes ways to reduce the environmental and monetary costs.

Review On Quarrying Methods Suitable For Space Mining Missions, Daniel Chpolianski, Zong-Xian Zhang

Journal of Sustainable Mining

In this review paper, existing mining techniques and technologies are scrutinized for the purpose of superterrestrial use. Different aspects and challenges of a space mining mission are examined in light of the viable iron-nickel quarry operation on M-Type (metallic) asteroids. The research and findings presented in this work cover different disciplines of science and engineering, including Geology, Rock Engineering, Space Exploration, and Explosives Engineering. The particular focus of this study is on the application of shaped charge explosives in military munitions, oil well perforations, tunneling, open-pit mines, and bolder fracturing that could be deployed in asteroid mining missions. The central …

Municipal Waste Management Based On Geomechanical Assessments Of The Landfill Site Slope – A Case Study In Southern Poland, Tomasz Janoszek, Phu Minh Vuong Nguyen, Jacek Grabowski

Journal of Sustainable Mining

Over time, municipal waste landfills tend to go higher and become larger. The stability of the municipal landfill slope is one of the basic geotechnical tasks. This task ensures continuous waste deposition on the landfill surface and safety in its surroundings. With the increasing height and volume of the landfill, it is difficult to estimate the available area of the municipal landfill, where more waste can be safely deposited due to a number of variable factors, such as the geotechnical conditions of the municipal landfill, the morphological composition, age, and degree of compaction and decomposition of the deposited waste.

This …

Coal-Rock Interface Imaging Based On Acoustic Remote Reflection Logging Within Crossing Boreholes Using The Finite Element Method, Xu Hongyang, Zhai Cheng, Xia Jigen, Sun Yong, Dong Xingmeng, Lai Yongshuai, Yu Xu, Xu Jizhao, Cong Yuzhou

Coal Geology & Exploration

The presence of small geological structures is the main cause of coal and gas outbursts, making the precise detection of these structures an urgent need. High-precision detection of coal-rock interfaces is essential for identifying small structures and achieving transparent mining faces. The acoustic remote reflection logging technology, with a large detection range, a high resolution, and imaging capability, can accurately identify coal-rock interfaces. In this context, this study proposed a technique for coal-rock interface detection based on acoustic remote reflection logging within crossing boreholes. Specially, by placing acoustic detectors in crossing boreholes, the array waveforms generated by the coal-rock interfaces …

Positioning Error Compensation Of Drilling Robot Arm For Coal Mine, Liang Chunmiao, Yao Ningping, Yao Yafeng, Peng Tao

Coal Geology & Exploration

At present, the pose of drilling robots is mostly adjusted by manual remote control and manual retest in combination. Full automatic adjustment has not been achieved. Besides, due to the low precision of open-loop control and inadequate automation capability, the accurate hole positioning and automatic construction of hole groups cannot be realized by drilling robots with water exploration and discharge, outburst prevention and punching prevention in coal mines. Herein, the kinematic model of drilling arm was established by analyzing the structure and action of the drilling robot’s drilling arm. Meanwhile, the dip angle factors such as machining error, body deformation …

Development And Application Of An Automatic Online Testing Instrument For The Funnel Viscosity And Density Of Drilling Fluids, Xie Hui, Zheng Liqun, Liu Fulin, Liang Mengjia, Liu Xuan, Cai Jihua, Yang Xianyu, Hou Jiwu

Coal Geology & Exploration

In recent years, the research on the automatic performance testing technology for drilling fluids has achieved significant progress both domestically and internationally. However, automatic drilling fluid testing instruments face challenges, such as high costs, complicated structures, and restricted working environments. Given these challenges, this study developed an automatic online testing instrument for the funnel viscosity and density of drilling fluids. The testing instrument consists of mud pumping, testing, cleaning, and control modules, which are built using a programmable logic controller (PLC), an Internet of things (IoT) module, a pressure sensor, an ultrasonic sensor, a peristaltic mud pump, an electric ball …

High-Accuracy Reconstruction Of Missing Ground-Penetrating Radar Signals Based On Projection Onto Convex Sets In The Curvelet Domain, Wu Qiming, Wang Honghua, Xi Yuhe, Wang Yucheng

Coal Geology & Exploration

Influence by the acquisition environments and instrument performance, missing signals and destructed channels are inevitable in measured ground-penetrating radar (GPR) profiles. They can cause event discontinuity of reflected and diffracted waves generated by targets, severely impairing the accuracy and resolution of subsequent processing and imaging. Hence, by combining the projection onto convex sets (POCS) algorithm extensively used in image processing with the curvelet transform exhibiting high sparsity, this study proposed a high-accuracy reconstruction method for missing GPR signals based on curvelet-domain POCS. Building on the compressive sensing theory, the objective function for missing signal reconstruction based on discrete curvelet transform …

Application Of The Horizontal Seismic Profiling-Based Advance Detection Technology To The Excavation Of Rock Roadways In Coal Mines Using Tunnel Boring Machines, Zhang Sheng, Chen Zhao, Lu Song, Yang Zhanbiao, Ji Panjun, He Fei, Lu Yiqiang, Liu Jiawei

Coal Geology & Exploration

With the gradual application of full-face tunnel boring machines (TBMs) to the excavation of rock roadways in coal mines, there is an increasingly urgent need for the accurate and rapid advance prediction of unfavorable geological structures. This study analyzed the characteristics of active-source seismic wave-based advance detection methods and the applicability of the advance detection technology based on TBM seismic while drilling (TSWD) with TBM rock-breaking vibration as a seismic source. Then, by combining the geological and production conditions of coal mine roadways, this study proposed a horizontal seismic profiling (HSP)-based advance detection method applicable to the excavation of roadways …

Early Warning And Prediction Of Kicks And Lost Circulation Accident During Rescue Drilling Of Mine, Chen Weiming, Wang Jiawen, Fan Dong, Hao Shijun, Zhao Jiangpeng, Qiu Yu

Coal Geology & Exploration

In order to solve the problems such as the difficulty in early warning and prediction of kicks and lost circulation accidents during emergency rescue drilling of mine, a machine learning-based early for warning and prediction model of drilling process was established. Firstly, the accident characterization parameters of the drilling parameters in the early stage of kicks and lost circulation accidents were analyzed. Secondly, the accident characterization parameters were cleaned and processed. On this basis, XGBoost and early warning model was used to carry out the early diagnosis and identification of kicks and lost circulation accidents. Then, the PSO-LSTM accident development …

Operation Process Identification For Intelligent Drill Rig Base On Analytic Hierarchy Process, Zhu Qianxiang, Luo Pengping, Wang Longpeng, Xing Wang, Wang Tianlong

Coal Geology & Exploration

It is very difficult to automatically identify the current process during the intelligent construction of coal mine drill rigs. In response to this, an operation process identification method was proposed, which includes hierarchical modeling of drill rig operation and probability inference of process execution. Firstly, the coupling process among the components of different granularity during the operation of drill rig is described and modeled based on the hierarchical analysis method, which reveals the interactive characteristics between equipment, function and system during the execution of each process. Secondly, Bayesian probabilistic reasoning method is introduced based on the above research to establish …

Analysis On Working Characteristics Of Cam-Roller Impact Mechanism Of Rotary Percussion Drilling Tool, Sun Yangqing, Yi Xianzhong, Wan Jifang, Ma Jianqi, Wu Jiwei, Yi Jun, Yin Guangpin

Coal Geology & Exploration

Rotary percussion drilling tools can effectively improve their rock breaking efficiency in the deep and hard strata, thus having broad application prospects. The cam-roller is the key mechanism to realize the impact action, but the complex and changeable downhole environment leads to serious damage to the mechanism, which in turn affects the efficiency of rock breaking. Based on the test drilling data of rotary impact drilling tools in several wells, the cam-roller dynamics model was established, the working characteristics under different strokes, speeds and drilling pressures were analyzed by Autodyn (explicit dynamics), and the deformation characteristics of the mechanism were …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

An Experimental Study Of Factors Influencing Gas Seepage In Confined Broken Anthracite, Li Zhen, Yu Yirui, Wang Hongwei, Feng Guorui, He Fulian, Wang Dezhang, Zhou Jinhui, Liu Luyan, Han Xinlei

Coal Geology & Exploration

The void structure evolution of broken coals in a caving zone directly affects the gas seepage characteristics of the zone, further influencing the gas migration and enrichment patterns in abandoned coal mine goaves. With the second generation of compaction-seepage-CT scanning experimental system for broken coals independently designed and developed, this study performed 162 sets of permeability experiments on broken anthracite samples with five particle size ranges under varying gas pressures, axial stresses, and void fractions. Key findings are as follows: (1) When gas migrated in broken anthracite, its pressure and flow rate kept dynamically changing until the adsorption equilibrium was …

Deformation And Collapse Patterns Of Gas Drainage Boreholes And A Precise Monitoring Technology, Xiao Peng, Huang Xiaosheng, Liu Xiaoxiao, Li Bingkun, Chen Liping, Chen Zixi, Zhang Chao, Cheng Renhui, Zhao Yajie

Coal Geology & Exploration

This study aims to promote the precise and intelligent monitoring of gas drainage boreholes. In the engineering background of a coal mine in Shanxi Province, this study conducted simulation experiments on the plugging of gas extraction boreholes under varying particle size ratios of simulated coal samples using distributed optical fiber monitoring and the Brillouin Optical Time-Domain Analysis (BOTDA). Then, this study established a mathematical model for calculating the borehole plugging rate of the test mine, revealing the deformation and collapse patterns of gas drainage boreholes. Furthermore, this study proposed a precise in-situ monitoring technology for the gas drainage boreholes in …

Exploring Geological Parameters Sensitive To Underground Coal Gasification, Zhou Ze, Yi Tongsheng, Qin Yong, Zhou Yongfeng, Wang Lingxia, Kong Weimin

Coal Geology & Exploration

Compared to ground coal chemical plants, underground coal gasification (UCG) requires gasifiers as geological bodies. Accurately understanding geological conditions is a critical prerequisite for UCG. To minimize the geological risks involved in UCG siting, this study systematically explored the geological parameters sensitive to UCG based on the intricate geological conditions of Guizhou Province, China. By collecting and organizing the exploration data of coal resources in Guizhou, this study established mathematical models for normalized, graded parameter value assignment, the algorithm of parameter weight vectors, and the algorithm of parameter weight product, with the purpose of obtaining the accurate quantitative data of …

A Method For Coal Seam Pressure Relief Based On Steel Cone Impact, Ren Zhimin, Lyu Mengjiao, Wang Fei, Wang Yu, Zhang Guangtai

Coal Geology & Exploration

This study aims to solve the mining safety problems caused by rock bursts in coal mines. With the geological mining conditions of the No.3 coal seam in the Wulihou coal mine in Zuoquan County, Jinzhong City, Shanxi Province as the engineering background, this study proposed a method for coal seam pressure relief based on steel cone impact. Specifically, based on the electromagnetic repulsion generated between energized coils, this study derived the functions of impact force produced when a magnetically driven coil-wound steel cone impacted the coal seam. Combining the theory on elastic mechanics, this study analyzed the stress field distribution, …

Two-Phase Flow Chokeling Results And Control In High-Pressure Gas Wells Producing Water, Liu Xinfu, Liu Chunhua, Li Qingping, Yao Haiyuan, Hao Zhongxian, Liu Yongfei

Coal Geology & Exploration

Prediction and control of two-phase flow chokeling in tight gas wellbores are essential for the normal operation and hydrate control of high-pressure gas wells producing water. The thermodynamic differential equations of energy, kinetic energy and temperature and models of chokeling field for two-phase energy, system heat, mass balance and flow were developed under the conditions of isentropic adiabatic, isobaric heat capacity, constant volume heat capacity, and chokeling energy. A methodology on predicting characteristics and control of two-phase flow before and after chokeling was proposed for gas-water two phase flow. It provided a theoretical basis for optimizing the structural parameters of …

Favorable Factors In Methane Production From Residual Coal Post-Biohydrogen Generation, Xia Daping, Liao Jiajia, Chen Zhenhong, Chen Xi, Guo Hongyu, Huang Dan

Coal Geology & Exploration

Determining favorable factors in methane production from residual coal post-biohydrogen production holds great theoretical and practical significance for improving the efficiency of methane production in the second stage of coal-based poly-generation. This study focuses on residual coal after hydrogen generation through anaerobic fermentation. Using coal samples from the Baiyinhua open-pit mine in Inner Mongolia as fermentation substrates, this study explored the dynamic trends of both the methane production and structure of the residual coal under different conditions by altering the aeration conditions and hydraulic retention time (HRT). Key findings are as follows: (1) Among the experiment groups with different atmosphere …

Uranium And Thorium Enrichment Characteristics Of Bauxite In Coal Measure Strata And Their Natural Gamma-Ray Responses, Zhang Xiaohui, Zhang Shangqing, Liu Dongna, Zhao Fenghua, Zhao Jun, Zhong Zhuanghua, Hou Xuqin

Coal Geology & Exploration

Shanxi Province boasts abundant bauxite resources occurring in coal measure strata, with the deep bauxite resources in this province subjected to progressive assessment. This study aims to further determine the endowment of aluminum resources within coals in the province and explore efficient exploration methods. To this end, this study investigated the bauxite layers in Upper Carboniferous coal measure strata in the Xiaoyi area, Shanxi Province. It examined 37 samples from three boreholes using methods such as optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence spectrometry (XRF), and inductively coupled plasma mass spectrometry (ICP-MS). Based on the analysis …

Numerical Simulation On Influence Of Skin Effect On Groundwater Flow Velocity In Wellbore, Wang Qihang, Li Xu, Guo Qiang, Kuai Dawei

Coal Geology & Exploration

Groundwater flow velocity in wellbore is usually measured by single-well tracking tests or Aqua Vision flow velocity and direction meters to calculate the groundwater flow velocity in the aquifer. Due to the impact of the skin structure, the groundwater flow field near the wellbore changes, causing a difference between the flow velocity in the wellbore and that in the aquifer. In order to investigate the influence of the skin effect on the groundwater flow velocity in the wellbore, a numerical model of groundwater flow that considers the skin effect was established using the COMSOL Multiphysics software. On this basis, the …

Law Governing Variations In Water-Pressure Transmission Rate In Confined Aquifers, Wang Wenxue, Wang Bosen, Gao Yanwei, Wu Bing, Nie Tianyu

Coal Geology & Exploration

The water pressure in aquifers is transmitted as energy, with a transmission rate much higher than the migration rate of water particles. The water-pressure transmission rate holds great significance for the safe construction and disaster forecast and prediction of underground engineering under high-pressure water aquifers and bodies. Focusing on the confined aquifers bearing no cohesive soil, this study explored the law governing the changes in the water-pressure transmission rate through theoretical analysis, numerical simulations, field experiments, and laboratory physical model tests. Key findings are as follows: (1) The transmission of water-pressure changes in the aquifers exhibited noticeable hysteresis. The transmission …

Experimental Study On Acoustic Emission Evolution Characteristics And Response Mechanism Of Damaged Rocks, Zhang Kai, Zhang Dongxiao, Zhao Yongqiang, Yang Yingming, Guo Weiyao, Sun Peng, Xu Linpeng, Fu Guangsheng

Coal Geology & Exploration

The evolution of rock internal damage is one of the causes of geotechnical engineering disasters, and revealing the response characteristics of key parameters during the rock failure could provide a basis for the identification instability state after rock failure, which is of great importance for the early warning and prevention of rock engineering disasters. Herein, the siltstone specimens with different damage degrees were prepared by cyclic loading-unloading tests, and uniaxial loading tests were carried out with the damaged specimens. On this basis, the relationship between the damage degree of specimen and the wave velocity, as well as the acoustic emission …

Yulong Snow Mountain National Field Observation And Research Station For Cryosphere And Sustainable Development

Bulletin of Chinese Academy of Sciences (Chinese Version)

No abstract provided.