Engineering Commons^™

Modeling And Optimization Of Froth Flotation Of Low-Grade Phosphate Ores: Experiments And Machine Learning, Ashraf Alsafasfeh

Doctoral Dissertations

”In this research work, bench-scale and micro-scale flotation tests were conducted to separate “minerals from silicate minerals using direct and reverse flotation approaches, respectively. Experiments were conducted at different flotation conditions including reagents’ type, reagents’ dosages, pulp’s pH, and flotation time.

In the direct flotation process, two polymers were selected to promote the depression of silicates: hybrid polyacrylamide-based polymers (Hy-PAM) and chitosan. Results indicated that the highest recovery of P₂O₅ (86.82%) was obtained when the Hy-PAM polymer was used compared with 66.7% and 40% when chitosan and commercial inorganic depressant were used, respectively. The experimental datasets obtained …

Investigation Of The Stability Of Liquid And Air Films By Synchronized Tri-Wavelength Reflection Interferometry Microscope, Yuesheng Gao

Dissertations, Master's Theses and Master's Reports

Liquid films are widely involved in many processes, such as froth flotation, oil extraction, foam/bubble stabilization, etc. In the meantime, air films are commonly seen in diverse fields like dust control, ink print, coating industry, and so on. Stabilities of these liquid/air films are of great importance to improve the processes. As more and more researchers are paying increasing attention to liquid/air films, tremendous efforts have been made to explore the properties of the films. On the one hand, some theoretical models have also been well developed in recent decades. State-of-the-art technologies, such as AFM, SFA, and RICM, have also …

A Novel Pixel-Based Multiple-Point Geostatistical Simulation Method For Stochastic Modeling Of Earth Resources, Adel Asadi

Dissertations, Master's Theses and Master's Reports

Uncertainty is an integral part of modeling Earth's resources and environmental processes. Geostatistical simulation technique is a well-established tool for uncertainty quantification of earth systems modeling. Multiple-point statistical (MPS) algorithms are specifically advantageous when dealing with the complexity and heterogeneity of geological data. MPS algorithms take advantage of using training images to mimic physical reality. This research presents a novel and efficient pixel-based multiple-point geostatistical simulation method for mineral resource modeling. Pixel-based simulation implies the sequential modeling of individual points on the simulation grid by borrowing spatial information from the training image and honoring conditioning data points. The developed method …

Upstream Tailings Dam - Liquefaction, Mladen Dragic

Graduate Theses, Dissertations, and Problem Reports (ETD)

The collapse of Dam I, tailings dam, at Vale S.A.’s (“Vale”) of the Córrego do Feijão Iron Ore Mine in Brazil was an accident that caused over 270 casualties and made irreparable damage to the surrounding environment. The exact reason for the failure is not known however, liquefaction was suspected to be the most influencing factor in the failure. Liquefaction failure of impoundment is increasing concern in the mining community and especially mine planners who will have to design and build the tailings dam. Different design methods are available with varied degree of challenges. Upstream construction methods, as one of …

Adaptation Of Coal Mine Floor Rating (Cmfr) To Eastern U.S. Coal Mines, Sena Cicek

Graduate Theses, Dissertations, and Problem Reports (ETD)

Floor heave—the excessive deformation and failure of floor strata—is a serious problem for many underground coal mining operations in the U.S. There is an accepted floor heave design methodology developed for the Illinois basin coal mines (Gadde, 2009). However, for Eastern U.S. coal mines in the Appalachian region, there is not any systematic design method to assess floor heave potential. In order to prevent stability problems associated with floor failure and to ensure the safety of the miners in this region, a systematic and proactive method to assess the potential of floor stability that also takes the floor failure mechanisms …

Solution Tool To Predict Filter Cake Formation For Acid Mine Drainage (Amd) Slurries, Roberto Ecuador Martinez Ochoa

Graduate Theses, Dissertations, and Problem Reports (ETD)

Acid Mine Drainage (AMD), also known as alkaline mine drainage resulted from abandoned and active coal mining areas has been a major water pollutant in the mid-Atlantic region of the United States affecting aquatic life, recreational areas, tourism, etc. AMD results from during and post mining activities all around the US and the world containing high levels of acidic materials such as sulfate and other heavy metals.

The United States Environmental Protecting Agency (EPA) has recommended the use of different mechanisms for mitigation purposes due to considerable existing and potential damage generated by AMD. This report focuses on the usage …

Solutions To Some Mine Subsidence Research Challenges, Jian Yang

Graduate Theses, Dissertations, and Problem Reports (ETD)

The objective of this work is to address three challenging topics, (1) effects of overburden key strata on subsurface subsidence; (2) effects of longwall subsidence on interstate highways and highway bridges; and (3) effects of dewatering mine water on surface subsidence over inactive room-and-pillar mines, in mine subsidence and to continue improvement of mine safety and health by reducing mine-subsidence related hazards.

Surface and subsurface subsidence events induced by underground mining activities are often capable of causing significant disturbances not only to surface structures, but also to subsurface structures. In this work, models and techniques to study three challenging topics …

Rational Drilling Control Parameters To Reduce Respirable Dust During Roof Bolting Operations, Hua Jiang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Roof bolting has been the primary means to improve mine safety in the aspect of preventing different types of roof falls in underground mines. However, based on the published researches, underground roof bolting operators exhibit a continued risk for overexposure to high levels of respirable coal and crystalline silica dust from the roof drilling operation. Inhaling these dust can cause coal workers’ pneumoconiosis (CWP), also known as black lung. Another job-related lung disease silicosis, a disabling and even fatal and irreversible illness, could be developed through overexposure to quartz-laden dust. A recent NIOSH research shows that the quartz content in …

An Interactive Mobile Equipment Task-Training With Virtual Reality, Lazar Zujovic

Graduate Theses, Dissertations, and Problem Reports (ETD)

Improving the quality of equipment training for the Heavy Equipment Operators (HEO) is a critical task in the ever-lasting effort to improve safety and eliminate equipment-related injuries in mining environments. Traditional miner training includes the use of hardcopy documents and video instructions. However, modern mobile and computer technology offers tremendous potential to improve the training process. One major responsibility for the heavy-machine operators is proper machine inspection. Establishing new training methods that utilize modern technologies—such as 360-degree images, videos, and Virtual Reality—and implementing computers for training purposes have a potential to help new operators learn how to conduct proper machine …

The Influence Of Spatial Variance On Rock Strength And Mechanism Of Failure, Danqing Gao

Graduate Theses, Dissertations, and Problem Reports (ETD)

The heterogeneity in the rock formation affects both rock behavior and the strength. The effect of heterogeneity is observed both at the laboratory scale and at the rockmass level. The mechanical properties of intact rock vary considerably at laboratory scale and often an average value is used for design purposes. Similarly, the values are arbitrarily scaled when used at rockmass level. In underground coal mines, the effect of variability of properties is often observed with the erratic roof failure events that occur throughout the mine. The approach often was to use the deterministic values from limited site data to estimate …

Microscopic Fabric Characteristics Of Typical Red Soft Rock In Badong Formation Under Uniaxial Compression Test, Xiao Zunqun, Wang Xin, Tang Dongsang, Dong Qiongying, Jiang Yinan, Yang Kai, Cao Tongtong, Deng Zhen

Coal Geology & Exploration

Red silty mudstone and argillaceous siltstone are the representatives of special rock and soil in Badong Formation, are easy to disintegrate when encountering water. According to the uniaxial compression test of rock samples, a numerical model of medium and soft rock uniaxial compression test was established based on PFC_2D program. With the characteristics of stress-strain curve, subsection quantitative parameter calibration method was used to calibrate the microscopic parameters of soft rock samples. The adjustment method and the ratio of tangential bond strength(σ_c/τ_c) control specimen under uniaxial compression failure mode. The uniaxial compression test of silty …

Analysis Of Suitable Development Technology Of Cbm(Gas) In Guizhou, Xu Xiaoqian, Meng Yingfang, Duan Zhengpeng, Li Guohong, Li Qingsong

Coal Geology & Exploration

In recent years, technical bottlenecks have been encountered in the practice of CBM exploration and development in Guizhou Province, selecting suitable development technology is one of the key issues. Based on the background that CBM exists in thin coal seams and geological structures are complicated in Guizhou, combined with successful development and utilization of CBM, the CBM development and utilization technology suitable for complex geological conditions in Guizhou was put forward. Air drilling is recommended for drilling in Guizhou, according to different distance of thin seams, such as optical casing composite fracturing and salvageable bridge plug fracturing can be used. …

Key Technology Of Drilling In-Seam Directional Borehole Of 3 000 M In Underground Coal Mine, Shi Zhijun, Dong Shuning, Yang Junzhe, Xu Chao, Hao Shijun, Li Quanxin, Chen Dianfu, Yao Ke, Liu Jianlin, Tian Dongzhuang

Coal Geology & Exploration

The pre-mining gas governance mode in Baode coal mine requires that long directional borehole of more than 3 000 m can be drilled along coal seam. In view of the existing technology and equipment, there are technical problems in the construction of ultra-long directional borehole, such as the difficulty of sliding drilling, the large hydraulic pressure consumption in inlet waterway, the limited transmission distance of wireline MWD signal, and incapability of flushing liquid recycle. The technology of friction reduction in sliding drilling based on the hydraulic thrust of DHM and the torsion penetration of the ultra-long drilling tool, the technology …

Extension Model Of Fracturing Cracks Of Translayer Horizontal Well In Roof Of Soft Coal Reservoir, Wang Zhirong, Hu Kai, Yang Jie, Chen Lingxia

Coal Geology & Exploration

In order to study the propagation rules of hydraulic fracturing crack formed by a horizontal well in roof to coal seam, taking the Permian-Carboniferous coal field in North China as an example, through the classical theory of fracture mechanics, damage mechanics and fluid mechanics, combined with field actual data, the modeling and verification of the space-time evolution law of the crack propagation distance and fracturing time were carried out. Firstly, considering the additional stress of perforation, the characteristics of primary fracture and the permeability characteristics of rock formation, the calculation formula of cracking pressure of vertical hydraulic fracture caused by …

Technology Feasibility Of Gas Drainage With Comb-Shaped Long Borehole In Floor Instead Of Translayer Borehole, Li Hong, Liu Mingju, Hao Guangsheng, Deng Qigen, Dong Yanjun

Coal Geology & Exploration

Drainage technology of translayer borehole in floor roadway and directional long hole are the most important gas control measures in high gas and outburst-prone mining face at present. The coal seam in Zhaozhuang mine has the characteristics of being soft and low gas permeability. It is difficult to drill and form holes in a coal seam. For gas control, the major method is to drill a translayer borehole to eliminate gas outburst, supplemented by in-seam gas drainage boreholes. However, there are shortcomings such as large engineering volume, long construction period and high cost of drilling in floor rock roadway. The …

An Improved Method For Characterizing Coal Metamorphism By Xrd, Wang Chao, Zhao Younan, Wang Zhenwei, Lu Zhaolin

Coal Geology & Exploration

At present, the X-ray measurement method of coal metamorphism has the problem that the γ band is not well divided, the δ peak information is not used, and the background of the bottom is unreasonable. The X-ray diffraction pattern of coal with different metamorphosed degrees is compared and studied. It is proposed to correct the metamorphic coefficient formula by using the information of the slope of the 002 peak, the extended half-height width and the δ peak without deducting the so-called background information. The calculation of the XRD patterns of coal samples with different degrees of metamorphism is verified. The …

Effect Of False Boundary Of Microscopic Image On Automatic Identification Of Maceral Group, Song Xiaozhong

Coal Geology & Exploration

In automatic detection of coal petrology by image analysis technology, it is found that the boundary of various components in the microscopic image of coal petrology demonstrates a "rim" of gray transition zone, and the pixel of this rim cannot reflect the true gray level of the components on both sides. In order to analyze its influence on the identification and detection of macerals, the characteristics and causes of the false boundary between various adjacent components were studied with analysis of microscopic images collected from a large number of coal samples in China. Generally, the false boundary is ring-shaped or …

Effects Of Iron-Nickel Ion Combination On Methane Produced By Lignite Fermentation, Xia Daping, Huang Song, Zhang Huaiwen

Coal Geology & Exploration

In order to study the mechanism of the influence of exogenous optimal iron-nickel ions combination on the gas production process of fermentation, taking Daliuta lignite as an example, experiments were carried out with different contents of iron-nickel ions and the optimal concentration of single ions was elected. The optimal combination concentration of iron-nickel ions were determined by combined design of quadratic regression and common rotation. The fermentation broth of experiment group and blank group(not to added any ions), the coal sample of before and after experiment were analyzed by gas chromatography, X-ray diffraction, Fourier transform infrared spectroscopy, etc. The results …

Origin And Geochemical Characteristics Of Coalbed Methane In Abandoned Coal Mines, Panzhuang Block, Southern Qinshui Basin, Liu Chao, Feng Guorui, Zeng Fangui

Coal Geology & Exploration

In order to analyze the carbon and oxygen composition and origin of the coal seam gas(CSG) in abandoned mines, Panzhuang block, south of Qinshui basin, in this paper, the coalbed methane and produced water samples were collected. The results show that the CSG of abandoned mines is dominated by CH₄, the average is 91.99%, with minor amounts of N₂(6.73%) and CO₂(1.26%). The δ¹³C values of CH₄ range from -31.36‰ to -33.53‰, with an average of -32.25‰, the hydrogen isotope(δD) value is between -182.76‰ and -193.20‰, and the average value …

Mine Water Inrush Rescue Model Based On Optimized Spfa Algorithm, Cai Mingjie, Zhu Xi’An, Liu Demin, Wang Zhangang

Coal Geology & Exploration

Due to the occurrence of coal mine water inrush accidents, it is easy to cause major personnel and property losses. In order to improve the emergency rescue capability of mine water inrush disasters and reduce the water inrush hazard, a mine water inrush rescue route model was proposed. The undirected map and the adjacency list were used to describe and store the mine roadway network. According to the calculation ratio of the height of the water level and the height of underground personnel in roadway, the safety coefficient of the roadway was calculated, and then the equivalent length of the …

Optimization Study On Correlation Method Of Multiple Coal Seams, Shu Jiansheng, Ma Liang, Jia Lilong

Coal Geology & Exploration

At present, the development trend of coal mining in China is transferring from the east to the western regions. The Yan'an Formation coal bearing measures middle Jurassic is the most widely distributed in the west, it is of the continental sedimentary environment, which has the characteristics of big change of lithofacies, multiple coal seams, unstable coal seams and less marker, there are difficulties in coal seam correlation, such as lack of basis and multi-solution phenomenon. Based on the wide application of high precision seismic exploration and digital logging technology, the fine correlation of terrestrial multi-coal seams was carried out by …

Simulation Of Seepage Water Inrush Mechanism And Strength Controlling Factors Of Collapse Column, Huo Bingjie, Xie Zhenhua, Fan Zhanglei, Jing Xuedong

Coal Geology & Exploration

In order to study the mechanism and main control factors of seepage water inrush in roadway affected by collapse columns, Darcy, Brinkman and N-S equations were used to describe the linkage system of flow field in aquifer, collapse column and water inrush roadway. Variables such as different parameters and different boundaries were selected to analyze the main factors influencing the seepage water inrush intensity of collapse columns. The results show that under the conditions of constant pressure and flow, the increase of aquifer permeability will lead to the increase of flow velocity in an area where the aquifer meets the …

Particle Swarm Optimization-Based Bionic Principle For Solving Hydrodynamic Dispersion Coefficient In Jiang'an Campus, Mei Jie, Li Guangwei, Xia Chengcheng, Liu Yaping, Liu Wen, He Xinyue

Coal Geology & Exploration

Hydrodynamic dispersion coefficient is an important parameter in the study of solute transport in groundwater. In order to understand the transport law of pollutants in groundwater, the particle swarm optimization(PSO) algorithm based on bionic principle is used to solve the hydrodynamic dispersion coefficient of phreatic aquifer under natural flow field in the dispersion test site of Jiang'an Campus of Sichuan University. Compared with the least-square method and the standard curve comparison method, the results show that the results of the standard curve method are subject to subjective influence, and the errors are relatively large. The results of least square method …

Surface Subsidence Law Caused By Fully Mechanized Caving Mining Under Railway, Deng Niandong, Yao Ting, Shang Hui, Liu Donghai

Coal Geology & Exploration

In order to ensure the safe running of the special railway for Guozhuang coal mine, the law of surface movement and deformation in goaf of the coal mine was studied on the basis of the analysis of the actual observation data, the monitoring scheme and control measures of railway under dynamic coal mining conditions were put forward in accordance with that. The results show that the surface movement and deformation are intense, the subsidence value is large, but the subsidence velocity is relatively small on account of fully mechanized caving; Surface subsidence coefficient, the main impact tangent tanβ, …

Nishihara Acceleration Model-Based Experiment Of Creep Characteristics Of Coal, Qu Lina, Li Bo

Coal Geology & Exploration

For conquering limitation that the traditional Nishihara model cannot describe the accelerated creep characteristics of coal body, according to the visco-elastic-plastic flow characteristics of coal in the accelerated creep stage, a nonlinear visco-elastic-plastic model was used to replace the ideal viscoelastic-plastic body in Nishihara model to establish the improved Nishihara acceleration model. And creep equation of the improved model under equal confining pressure triaxial condition was also deduced. Afterwards, the improved accelerated creep model was analyzed by the creep test data of coal specimens in the triaxial creep tests using the method of model identification. The results show that the …

Shear Strength Characteristics Of Slope Soil In Dumping Site In High-Cold Mining Area, Zhou Linhu, Yang Youqing, Hu Xiasong, Li Xilai, Wang Tao, Liu Changyi

Coal Geology & Exploration

The paper aims to study the shear strength characteristics and the influencing factors of the root-soil composite systems of herbs in the dump slope of the high-cold mining area. The dumping site of Jiangcang mining area of Muli Coalfield, located in the northeastern Qinghai-Tibet Plateau, was selected as the study area. For the dump slope which was planted with Elymusnutans Griseb., combined with Poacrymophilakeng, density, moisture content and root content of different depths of root-soil composite systems below the surface of slope were tested; the cohesion and the internal friction angle of soil without roots and root-soil composite systems …

Optimization Of Surface Contact-Based Thermal Conductivity Model Of Cemented Particles, Chen Yuanjiang, Jiang Zhiqiang, Tan Zhiren

Coal Geology & Exploration

In order to explore better the variation law of thermal conductivity of geomaterials, and reduce the thermal damage caused by the problem, according to the structural characteristics of the cemented particles, combined with the effective medium thermal conductivity model and the surface contact thermal conductivity model, the effective thermal conductivity calculation model suitable for the geotechnical cemented particulate material was constructed, and the state of the particulate matter and the cementitious matrix were considered. The transient hot wire method was applied to test the thermal conductivity of the experimental test block, and the predicted values were compared with the measured …

Numerical Calculation Of Heat Transfer In Single Medium-Deep Geothermal Well, Shang Hongbo, Zhao Chunhu, Jin Dewu, Xu Shuanhai, Wang Xiaodong, Zhang Weidong, Han Yongliang

Coal Geology & Exploration

Medium-deep geothermal single well heat transfer is a technology of developing geothermal energy to "obtain heat without extracting groundwater". This technology has the advantages of not damaging the groundwater environment and taking more heat. However, there are few studies on the numerical calculation of single well heat transfer above 3000m depth. In this paper, based on the geothermal geological conditions in Xi'an, the numerical method was used to calculate the heat transfer of a medium-deep geothermal single well with different well structures (L-shaped directional wells and cluster directional wells) under the scenario of continuous operation of a heating season. The …

Fluid Factor Of Fracture And Seismic Velocity Response In Anisotropic Coal Beds, Li Qin, Ma Suibo, Zhao Bin

Coal Geology & Exploration

The storage and transport of gas and water in coal seam are related to the density, strike and filler of cracks. Research on the identification and prediction of coal seam cracks will be helpful to prevent and control disastrous accidents in coal mines, such as water inrush and gas outburst. It plays an important role in the safety evaluation of coal mining. Based on the theory of fracture equivalent model, the variation characteristics of fluid factor in coal seam crevices with different fillings and fracture weaknesses parameters(fracture density, aspect ratio, volume modulus, shear modulus, Lamé parameters) are analyzed by combining …

Influencing Factors Of Azimuth Electromagnetic Wave Roof And Floor Detection While Drilling Along Coal Seam, Chen Gang, Fan Yiren, Li Quanxin

Coal Geology & Exploration

Aiming at the problems of poor detection accuracy and low efficiency of roof and floor interface in horizontal well drilling in coal mine, the design idea of explosion-proof azimuth electromagnetic wave logging tool while drilling in coal mine is put forward. In order to suit the working environment of underground coal seam, the influence of instrument parameters such as source distance, transmitting frequency and coil installation angle on signal response was obtained by forward simulation. The results show that the received signal strength of the azimuth electromagnetic wave instrument while drilling increases with the increase of transmitting frequency, coil distance …