Engineering Commons^™

Radio Frequency Wave Propagation Modeling Within Obstructed Underground Mining Environments For Effective Miner Localization During Mine Emergencies, Emmanuel Atta Antwi

Doctoral Dissertations

The reliability of underground wireless communication systems remains a significant challenge, particularly during emergencies when the mine environment becomes severely obstructed by debris, dust, and humidity. These environmental and geometric conditions result in significant attenuation of electromagnetic (EM) waves and multipath effects that undermine miner localization and rescue operations. Existing Vector Parabolic Equation (VPE) models are efficient for straight or mildly curved tunnels but fail to account for the random and obstructive conditions typically encountered during underground emergencies. This research develops a novel radio propagation model for EM wave behavior in underground mine drifts under geometrically obstructed conditions. The model …

Applying Human System Integration Principles To The Investigation, Design And Validation Of Interventions For Self-Escape In Underground Mines, Eugene Adubofour Gyawu

Doctoral Dissertations

This dissertation investigates the use of human systems integration (HSI) to develop technologies for miners’ self-escape during a mine emergency, addressing barriers that compromise miner safety during emergencies.

Recognizing the inherently hazardous nature of underground mining, this study has three core objectives: (1) assessing miners' perceptions of proposed self-escape interventions, (2) designing interventions based on these insights, and (3) validating their effectiveness using experimental testing. This work evaluates self-escape interventions for both coal and metal/non-metal miners using scenario-based surveys, information design reviews, label designs and experimental testing methods varying across three distinct studies.

Results reveal that miners identified improvements to …

Mid-Field Shock And Impulse Estimation Methods For Blast Loading On Tall Targets, Ethan Allan Steward

Doctoral Dissertations

Blast resistant structural design continues to be a major research area for governments around the world due to explosive threats from both state and non-state actors. Many of the typical targets of explosive attacks, such as government buildings, commercial high rise office buildings, and apartment complexes are mid to high-occupancy buildings that present a tall profile relative to the charge size and are often clad in curtain walls. In blast resistant structural design, the origin of a shock wave is typically assumed to be in the far-field, creating a wave that is nearly planar and parallel to at least one …

Viscoelastic Materials Evaluated For Blast-Resistant Designs, M. Sutter, C. Thomas, A. D. Douglas, F. Dogan, C. E. Johnson

Mining Engineering Faculty Research & Creative Works

Viscoelastic materials have extensive military applications due to their energy absorption capabilities, with the potential to reduce blast energy imposed on buildings, vehicles, and personnel. Based on current literature, limited information is available regarding the mitigation of blast energy related to these uses. The impact of thickness, nanoparticle addition, and layering variation was assessed in this study using commercially available viscoelastic materials in open-air blasts of Composition C4 to determine shock energy mitigation capabilities. Time-pressure waveforms were recorded to identify optimal changes in shock wave characteristics: reduced peak pressure, positive phase duration, and impulse, with increased rise times. Results were …

Application Of Gurney And Flight Of Fragment Calculations For Water Jet Velocities In Explosive Applications, Rachel L. Bauer, Tate B. Friedrich, Catherine E. Johnson

Mining Engineering Faculty Research & Creative Works

This study investigates the application of Gurney and flight of fragment equations, typically used to predict metal fragment velocities, in modeling the water jet behavior. Three shotgun cartridge sizes were used as the energy source: 2.59 g, 5.83 g, and 7.13 g. Two configurations were tested: standard (full-barrel water load) and "negative 8" (partial water load). High-speed footage captured water column velocities, and Gurney models, including infinitely tamped and open-faced configurations, combined with the flight of fragment model were used to assess prediction accuracy. Results showed charge strength significantly affects water column velocity, with higher strengths yielding greater stability and …

Optimizing Hy Wet Ball Mill Efficiency Using Response Surface Methodology, Peng Chen, Ying Hou, Hongxu Lv, Ahmed Sobhy

Mining Engineering Faculty Research & Creative Works

This study uses response surface methodology (RSM) with a central composite design to optimize the HY wet ball mill work index. Key operational parameters—ore quantity, water addition, and media proportion—were systematically investigated. Variance analysis identified these factors as statistically significant (p < 0.0001), with ore quantity exhibiting the strongest influence (F value = 82.67). Optimal conditions (water addition: 1083.880 mL, media filling rate: 40.362%, ore quantity: 1827.130 g) achieved a minimum work index of 10.195 kW h t⁻¹. Validation tests confirmed the model's accuracy, yielding an average work index of 10.168 kW h t⁻¹ (deviation: 0.027 kW h t⁻¹). Compared to single-factor tests, RSM optimization reduced energy consumption by 3.76% (0.3975 kW h t⁻¹), translating to annual savings of $214,000 for a mid-sized processing plant. This demonstrates RSM's efficacy in …

Exploring The Link Between Hy Wet Ball Mill Work Index And Grinding Energy Consumption, Chen Peng, Hou Ying, Lv Hongxu, Sobhy Ahmed

Mining Engineering Faculty Research & Creative Works

In evaluating ore grinding energy consumption using the Bond ball mill work index, discrepancies were identified. As a result, an investigation into the determination method of Hou Ying (HY) wet ball milling work index (WHY) for Gongchangling magnetite ore was conducted to determine the correlation between WHY and grinding energy consumption at varying particle sizes. The research results indicated that WHY had an error less than 3.33%, which is closely aligned with on-site grinding energy consumption. This surpassed the numerical error of 15.9% in the Bond ball grinding power index and demonstrated superior accuracy in representing ore grinding energy consumption, …

Enhancing Safety In U.S. Coal Mines Through A Rib Support Recommendation Tool, Alper Kirmaci, Dakshith Ruvin Wijesinghe, Dogukan Guner, Kutay E. Karadeniz, Cameron Mitchell, Taghi Sherizadeh

Mining Engineering Faculty Research & Creative Works

Despite ongoing efforts to enhance coal rib stability, the underground coal mining sector continues to face incidents of rib failure, leading to injuries and fatalities. The development and validation of effective rib support systems are crucial for mitigating these risks. Unfortunately, a standardized design methodology that accommodates the diverse geological conditions of U.S. coal mines is missing. Current practices are often based on trial-and-error or outdated methods, yielding unreliable outcomes. This research aims to fill this gap by creating a comprehensive methodology for designing rib support systems suitable for U.S. underground mines. It encompasses in situ pull-out tests of coal …

Life Cycle Assessment And Techno-Economic Analysis Of Mine Tailings As A Sustainable Raw Material For Mineral Carbonation And Recovery Of Critical Minerals, Vida Amankwaa

Dissertations, Master's Theses and Master's Reports

This study assesses the feasibility of using mine tailings for mineral carbonation and nickel recovery through a comprehensive Life Cycle Assessment (LCA) and Techno-Economic Analysis (TEA). The LCA quantifies greenhouse gas emissions, energy use, and resource consumption, while the TEA evaluates capital investment, operational costs, and process efficiency. The conventional beneficiation process at Eagle Mine serves as a baseline, highlighting its environmental footprint and operational costs. Results indicate that tailings reprocessing incurs higher costs ($34.76 per tonne of tailings processed) compared to conventional ore processing ($25.90 per tonne) due to increased energy consumption and material handling requirements. Additionally, several mineral …

Iron Ore Tailings Reprocessing By Electrostatic Separation Plus Two Stages Froth Flotation, Vincent Bailey Arohunmolase

Dissertations, Master's Theses and Master's Reports

The reprocessing of tailings is crucial for recovering valuable iron and reducing the environmental impact associated with tailings disposal. This study investigates the practicality of reprocessing tailings to enhance iron oxide content, combining electrostatic separation with a two-stage froth flotation process using oleic acid (direct flotation) and amine (reverse flotation). The primary goal is to efficiently recover valuable iron from tailings, thereby reducing waste and promoting sustainable resource utilization. The process aims to upgrade the iron oxide content to around 93-99% Fe₂O₃, making the recovered material suitable for the production of direct-reduced iron.

Electrostatic separation was …

Shock Wave And Vortex Ring Dynamics From Explosively Driven Shock Tunnels, Rachel Louise Bauer

Doctoral Dissertations

"Blast and shock tubes are frequently used to create shock waves to study their effects and impacts on structures, humans, and personal protective equipment. These tubes are also found in other industries including wind tunnels for aerodynamic testing, jet engines for propulsion research, spacecraft reentry simulations, and industrial applications such as material testing and high-velocity impact studies. Despite their widespread use, there is no standard design, with variations in geometry, size, and energy sources. Current research only evaluates the peak pressure of the shock wave produced and does not consider the effects of changing the size or geometry of the …

Investigation Of Shockwave Behavior To Inform Helmet Design Using Schlieren Imagery And Free-Field Blasts, Cody Jh Thomas

Doctoral Dissertations

"Ballistic resistance of military helmet designs is a prioritized feature to protect warfighters from traumatic brain injury. However, injuries from shock-based threats have not been optimized for warfighter protection and have resulted in the prevalence of blast-induced traumatic brain injury (bTBI). Research gaps were identified in understanding the under wash effect using free field blasts and schlieren imagery. Thus, the following were investigated: (1) overpressure changes on a warfighter’s head due to directionality from a blast, (2) shock wave dampening effects of viscoelastic materials in helmets, and (3) geometric effects of a helmet brim design in the reduction of bTBI. …

Advancing Refuge Alternatives In Mine Emergencies Using Advanced Numerical Simulation, Kutay Emre Karadeniz

Doctoral Dissertations

"Incidents and emergencies within underground coal mines can result in severe injuries or even loss of life, particularly due to the hazardous nature of mine explosions. One of the options for the miners to protect themselves from these hazards is to be sheltered in a refuge alternative (RA). However, the literature lacks an analysis of survivability constraints and the structural integrity of RAs when exposed to geomechanical changes and the ability to withstand the impact of coal mine explosions. In this study, based on the utilization and survivability constraints, basic human requirements and the required physical specifications of RAs during …

Delineating Underground Geological Formations: An Integrated Lidar And Camera-Based Approach For Enhanced Feature Identification In Poorly Lit Mining Environments, Timothy James Batchler

Graduate Theses, Dissertations, and Problem Reports (ETD)

Underground mining environments present challenges in accurately identifying geological formations and potential hazards due to poor lighting conditions and confined spaces. Traditional imaging methods often fall short, making it difficult to detect critical geological features such as limestone, shale, and other rock formations. This research addresses these challenges by integrating camera imagery with Light Detection and Ranging (LiDAR) data to improve geological formation detection in poorly lit mining settings.

LiDAR, with its ability to generate high-resolution three-dimensional models in low-light or dark conditions, offers a promising solution to these limitations. By combining LiDAR’s precise 3D models with camera imagery, the …

Enhancing Pillar Stability Assessment In Underground Limestone Mines Using Lamodel: Integrating Empirical Strength Equations For Improved Ground Control, Alim Elibol

Graduate Theses, Dissertations, and Problem Reports (ETD)

Underground stone mining accounts for approximately 21% of all underground mining operations in the United States, with more than 2,000 workers employed in this sector as of 2019. Ground control failures, particularly those involving massive pillar collapses and roof falls, pose significant safety hazards, contributing to 40% of fatalities and 15% of lost workdays since 2006. Several massive pillar collapses have occurred in active limestone mines from 2015 to 2021, and a fatal incident was reported in January 2022 in a mine operating within the Loyalhanna formation. Given these risks, accurate stability assessment tools are essential for improving mine safety. …

Selective Recovery Of Critical Minerals (Ni, Zn, Co, And Mn) From Acid Mine Drainage Utilizing Ion Exchange And Selective Precipitation Processes, Esteban Albeiro Cardenas Restrepo

Graduate Theses, Dissertations, and Problem Reports (ETD)

Critical minerals (CMs) are essential for U.S. national security and technological development. The U.S. heavily depends on imports of these minerals from other countries, making supply chain disruptions a likely scenario. In consequence, finding alternative sources to conventional mining for these elements has become a topic of interest in recent years. Acid Mine Drainage (AMD), once solely viewed as an environmental problem, has emerged as a potential alternative source for CMs. AMD is a naturally occurring process where surface and underground water interact with sulfur-bearing minerals in the presence of oxygen and microorganisms. This interaction causes the water to become …

Investigation Of Spalling Effects On The Brittle Behavior Of Rectangular Pillars In Underground Stone Mines, Yolver Yesid Jimenez Ibanez

Graduate Theses, Dissertations, and Problem Reports (ETD)

Recent catastrophic collapses in U.S. limestone mines have exposed the limitations of traditional empirical design formulas for brittle rock masses. These events, especially those involving slender pillars, underscore that traditional methods often fail to account for progressive, spalling-dominated failure, highlighting a crucial gap in our understanding. This research addresses this issue by conducting a comprehensive investigation into the mechanics of spalling in rectangular stone mine pillars, utilizing advanced three-dimensional numerical modeling with FLAC3D combined with LiDAR-based geometric modeling.

The stability of a pillar is governed by a complex interaction between the in-situ stress field, rock mass properties, and pillar geometry. …

Rare Earth Element Recovery From Acid Mine Drainage Using Ion Exchange And Selective Precipitation Processes, Paubla Andrea Gallego Lopez

Graduate Theses, Dissertations, and Problem Reports (ETD)

Rare earth elements (REEs) are used in high-tech applications due to their electromagnetic and optical properties. As global demand for REEs surges, the limitation of primary mineral deposits has increased interest in alternative sources. One such source is acid mine drainage (AMD), which, although typically low in REE concentration, offers a promising avenue for recovery. Among the emerging recovery methods, ion exchange has shown promise due to its effectiveness at low concentrations and lower operational cost than conventional techniques such as acid leaching and solvent extraction.

This research focused on developing a recovery process by combining ion exchange with selective …

A Comparative Study Of Conventional And Statistically Active Corrosion Methods For Corrosion Growth Assessment Of A 24-Inch Gas Pipeline, Rudi Rinaldi, Jaka Fajar Fatriansyah

Journal of Materials Exploration and Findings

Component failures in oil and gas pipelines can have fatal consequences, leading to operational downtimes and environmental damage. Knowledge of the corrosion growth rate is fundamental to pipeline integrity management, as it is essential for risk assessment and decisions related to asset management. This article aimed to compare two approaches for the corrosion growth estimation of the 24-inch offshore gas pipeline: the conventional method versus the Statistically Active Corrosion (SAC) method. This article is based on the in-line inspection (ILI) results of two consecutive assessments from 2020 to 2023 of the entire 73 km of the pipeline. The results show …

Commingling Production Of Deep Coal-Measure Gas Through Hydraulic Fracturing: Propagation Patterns Of Induced Fractures And Their Determinants, Chen Hao, Li Guozhang, Qin Yong, Wang Jianguo, Shen Jian, Sun Yuqi, Yuan Erjun, Li Dian

Coal Geology & Exploration

Objective The commingling production of coal-measure gas represents a pivotal approach to enhancing the single-well production of unconventional gas in China. However, coal-measure gas reservoirs exhibit distinctly different material compositions and physical properties, leading to uncertainty of the propagation modes and developmental degrees of fractures in different reservoirs during the hydraulic fracturing of coal-measure gas reservoirs subjected to commingling production. Therefore, effectively coordinating the stimulation of multiple reservoirs for multi-gas commingling production is crucial for minimizing production costs and maximizing production capacity. Methods This study investigated the Linxing block along the northeastern margin of the Ordos Basin as an example …

Microscopic Fracture Characterization And Permeability Evolutionary Patterns Of Granites Under Cyclic Thermal Shock, He Jiangfu, Ren Chengcheng, He Kun, Yu Qihang, Li Xinru, Deng Xu

Coal Geology & Exploration

Objective This study aims to reveal the microscopic damage characteristics and permeability evolutionary patterns of high-temperature granite reservoirs fractured under cyclic thermal shock produced by low-temperature fluids like drilling fluids and circulating heat recovery media in the exploitation process of the enhanced geothermal systems (EGSs). Methods Using experiments on the fracturing characteristics of high-temperature granites under the conditions of varying cooling methods, numbers of thermal shock cycles, and cooling temperatures, this study determined microstructural characteristic parameters such as compressional wave (P-wave) velocity, pore volumetric fraction, and fractal dimension of granites across a temperature range of 25 to 700 ℃ under …

Identifying The Lithologies And Thicknesses Of Coal Seam Roofs And Floors Based On Multiparameter Logging Of Boreholes, Li Zhe, Gao Baobin, Lei Wenjie, Li Donghui, Li Zixin

Coal Geology & Exploration

Background In the process of coal mining, effective exploration methods for stratigraphic characteristics are crucial to underground operations. The reason is that the accurate stratigraphic characteristics of coal seams, along with the surrounding rocks of coal seam roofs and floors, facilitate the treatment of gas in coal seams, thereby ensuring safe and efficient coal mining. Methods Based on the multiparameter logging of boreholes crossing strata in a bottom drainage roadway, this study highlighted the lowstand, upgoing borehole trajectories, as well as the variations in parameters including natural gamma rays, spontaneous potential, and resistivity. By comprehensive comparison of the trajectories, video-derived …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Influence Mechanisms Of Dynamic Metamorphism On The Evolution Of Micro/Nano Pore Structures In Tectonically Deformed Coals, Liu Hewu, Lyu Xiaoxue, Hou Chenliang, Xiong Zuopeng

Coal Geology & Exploration

Objective Micro/nano pore structures in coals act as a significant space for gas occurrence. Exploring the evolutionary mechanisms of micro/nano pore structures in tectonically deformed coals (TDCs) under the influence of dynamic metamorphism assists in gaining a deep understanding of the mechanisms underlying coal and gas outbursts. Methods Using CO₂ adsorption experiments, Fourier transform infrared (FTIR) spectroscopy, and molecular dynamics simulations, this study investigated the evolutionary characteristics and mechanisms of micro/nano pore structures in different TDCs occurring within the No.72 coal seam of the Qi’nan Coal Mine in Suzhou Province. Results and Conclusions The results indicate that with enhanced …

Failure Depths Of Stope Floors Under Dynamic Loading Induced By Roof Breaking, Huang Qisong, Xu Bo, Feng Junjun, Lin Xiaofei, Cheng Jiulong, Peng Jun

Coal Geology & Exploration

Objective Accurately assessing the failure depths of stope floors is crucial for assessing floor water inrush risks. Conventional theoretical models for calculating the failure depths generally merely consider static loads from the support pressure and confined water's pressure in stopes, leading to large deviations between calculation results and actual situations. Therefore, constructing a more practical computational model that comprehensively considers the coupled effects of multiple force sources on the failure of deep floors can provide a scientific basis for the effective prevention and control of water hazards in deep coal seam floors. Methods Based on the dynamic elasticity theory and …

Construction And Correction Of A 3d Digital Twin For A Complex Gangue-Bearing Coal Seam, Zhang Meichen, Zhao Lijuan, Wang Yadong, Zhang Kai

Coal Geology & Exploration

Objective 3D digital twin for complex gangue-bearing coal seams are designed to achieve an information-based description of physical coal seams and faithfully map their virtual forms. digital twin is identified as a prerequisite for exploring the efficient cutting of intelligent shearers while providing an effective data guarantee for achieving unmanned mining. Methods Using data on samples from the mining face of coal seam 17 in the Yankuang Energy Group Co., Ltd. Shandong Province, this study proposed a methodology that integrates more information about the geological structural conditions of coal seams. Specifically, digital twining of iron sulfide nodules was performed using …

A Calculational Model For 3d Fault Complexity Based On Curvature Analysis And Fractal Dimensions, Yan Junsheng, Liu Zaibin, Fan Tao, Yang Hui, Liu Wenming, Du Wengang, An Lin, Liu Chenguang, Wang Xiaohui

Coal Geology & Exploration

Objective and Methods Faults are identified as one of the most threatening geological structural factors among hidden disaster-causing factors in coal mines. However, the 3D quantitative assessment of them remains challenging. Considering that existing quantitative indicators fail to fully reflect fault morphologies and there is a lack of 3D methods, this study proposed a calculational model for 3D fault complexity based on curvature analysis and fractal dimensions. This model improved the morphologies of traditional measurement volumes of fractal dimensions by employing the Delaunay tetrahedralization algorithm, thus effectively reducing the invalid values in calculating the 3D fractal dimensions of faults. Moreover, …

Exploration Of The Impacts Of Cement Sheath On Casing Stress Based On The Arching Effects Of Formations, An Fengchen, Miao Zhibo, Meng Siwei, Wei Ziying, Zhang Xiao, Zeng Jiaming, Wang Xiaohua

Coal Geology & Exploration

Objective With the growth in the demand for natural oil and gas and the technological progress of their production, the oil and gas well depths have been constantly setting new records. The increase in the depth corresponds to sharply increasing in-situ stress, leading to increasingly severe damage to the casing of ultradeep oil and gas wells. To enhance the bearing capacity of the casing under high in-situ stress, high-strength casing with a large wall thickness is typically employed, a measure which has been proved, however, less effective. Methods This study established a finite element model of the casing-cement sheath-formation system …

Hydrochemical Characteristics And Component Sources Of Water In Underground Reservoirs In The Daliuta Coal Mine, Zhang Haitao, Jiang Binbin, Zhang Haiqin, Li Peng, Wu Min, Hao Jingwei, Hu Yutian

Coal Geology & Exploration

Objective Underground reservoirs in coal mines are capable of storing and purifying mine water. A deep understanding of the hydrochemical characteristics and formation mechanisms of water in underground reservoirs is identified as an important prerequisite for large-scale development of technologies for mine water treatment. Methods This study investigated the underground reservoirs in the Daliuta Coal Mine within the Shendong area by testing and analyzing their influent and effluent water samples. Using methods such as the ion ratio method, multivariate statistical analyses (e.g., correlation analysis and principal component analysis (PCA)), and the positive matrix factorization (PMF) model, this study delved into …

Mechanisms And Influential Factors Of Rock Bursts In Tunneling Roadways Of Extra-Thick Coal Seams, Peng Yujie, Wang Qiang, Cao Anye, Xue Chengchun, Lyu Guowei, Hao Qi, Liu Yaoqi, Bai Xianxi, Li Dong

Coal Geology & Exploration

Objective Rock bursts occur frequently in tunneling roadways of extra-thick coal seams, significantly constraining safe coal mining. Investigating their mechanisms and influential factors is crucial to preventing and controlling such disasters in tunneling roadways of extra-thick coal seams. Methods Focusing on the tunneling roadway of mining face 250107-1 for an extra-thick coal seam within a coal mine in Gansu Province, this study established the discriminant indices for rock burst-induced roadway instability. By simulating the energy distribution patterns of surrounding rocks in the tunneling roadway using the FLAC^3D software, this study revealed the zonal energy characteristics of the surrounding rocks …