Mining Engineering Commons^™

Surface Chemisty Study Of Monazite Flotation In Coal Refuse Systems, Wencai Zhang

Theses and Dissertations--Mining Engineering

Rare earth mineral recovery from alternative resources such as coal and coal byproducts is increasingly important to provide an opportunity for economic recovery from U.S. sources. Currently, China produces the majority of the 149,000 tons of rare earth elements used annually worldwide of which the U.S. imports 11% or around 16,000 tons. There are no significant mining operations producing rare earth elements in the U.S. However, there are many U.S. sources containing rare earth minerals such as monazite including heavy mineral sand and phosphate operations. Monazite mineral particles of a few microns have also been detected in Fire Clay seam …

Calculation Of The Edge Effect Offset For High Extraction Coal Panels, Joshua Hescock

Theses and Dissertations--Mining Engineering

The Surface Deformation Prediction System (SDPS) program has been developed as an engineering tool for the prediction of subsidence deformation indices through the implementation of an influence function. SDPS provides reliable predictions of mining induced surface displacements, strains, and tilt for varying surface topography. One of the key aspects in obtaining reliable ground deformation prediction is the determination of the edge effect offset. The value assigned to the edge effect corresponds to a virtual offsetting of boundary lines delineating the extracted panel to allow for roof cantilevering over the mined out area.

The objective of this thesis is to describe …

Fundamental Improvement In The Tribocharging Separation Process For Upgrading Coal, Jinxiang Chen

Theses and Dissertations--Mining Engineering

Triboelectrostatic separation is a physical separation technique that is based on surface electronic property differences among minerals to achieve a separation. Minerals have different surface conductivities and electron affinities. They are charged differently in quantity and/or polarity after a tribocharging process. Particles with different surface charges move discretely under external electric field produce a separation. Electrostatic separation is a dry mineral processing method that does not require any water or chemical reagents. It can greatly simplify the processing circuit and reduce operating cost. Additionally, problems caused by water in conventional wet mineral processing such as water freezing, dewatering, water pollution …

Pore Pressure Measurement Instrumentation Response To Blasting, Kylie M. Larson-Robl

Theses and Dissertations--Mining Engineering

Coal mine impoundment failures have been well documented to occur due to an increase in excess pore pressure from sustained monotonic loads. Very few failures have ever occurred from dynamic loading events, such as earthquakes, and research has been done regarding the stability of these impoundment structures under such natural seismic loading events. To date no failures or damage have been reported from dynamic loading events caused by near-by production blasting, however little research has been done considering these conditions. Taking into account that current environmental restrictions oblige to increase the capacity of coal impoundments, thus increasing the hazard of …

Modern Rock Dust Development And Evaluation For Use In Underground Coal Mines, Robert Eades

Theses and Dissertations--Mining Engineering

Following the promulgation of new permissible respirable dust standards by MSHA in 2014, new alternative rock dusts were created that combined the advantages of current industry applications while potentially reducing miner exposure to respirable dust. Research was performed to compare the explosion suppressing and ejection characteristics of three new types of rock dust to existing rock dust types. Explosion suppression tests were conducted in a 38-L chamber where pressures were recorded. Angle of ejection tests were conducted using a high explosive shock tube and high speed photography to determine angle of ejection and lift velocity. A comprehensive comparison of the …

Techno-Economic Potential Of Enhanced Coal Recovery Through Middlings Liberation And Re-Processing, Shivani

Theses and Dissertations--Mining Engineering

The typical preparation plant producing coal for the utility market targets a relative separation density in the plant of around 1.60 whereas plants generating metallurgical coal use relative cut point density values approaching 1.50. In some cases, achieving the specified coal quality requires operating at lower cut point values, which results in a significant loss of valuable coal. In these situations, a middlings stream can be produced using a secondary separator or a three-product unit, which would allow crushing of the middlings for liberation purposes and re-introduction into the plant feed. In this manner, higher quality coal can be produced …

Rock Dust Surface Chemistry Modifications For Eliminating Cake Formation And Improving Dispersion In Coal Dust Explosion Mitigation Applications, Qingqing Huang

Theses and Dissertations--Mining Engineering

Rock dust has been historically applied to mitigate the coal dust explosion in either dry or wet form. Dry rock dust performs best in inerting the potential coal dust explosion due to the greatest dispersive properties. However, it undesirably exposes underground coal miners to respirable dust particles which imposes a severe health danger. Wet dust application is able to significantly reduce the floatable dust particles but another problem associated with caking is predominant. Caking phenomenon is usually used to describe the change of free-flowing bulk solids into agglomerated chunks. Unfortunately, the environmental conditions of an underground mine have the potential …

Utilization Of A Small Unmanned Aircraft System For Direct Sampling Of Nitrogen Oxides Produced By Full-Scale Surface Mine Blasting, Robert B. Mccray

Theses and Dissertations--Mining Engineering

Emerging health concern for gaseous nitrogen oxides (NO_x) emitted during surface mine blasting has prompted mining authorities in the United States to pursue new regulations. NO_x is comprised of various binary compounds of nitrogen and oxygen. Nitric oxide (NO) and nitrogen dioxide (NO₂) are the most prominent. Modern explosive formulations are not designed to produce NO_x during properly-sustained detonations, and researchers have identified several causes through laboratory experiments; however, direct sampling of NO_x following full-scale surface mine blasting has not been accomplished.

The purpose of this thesis was to demonstrate a safe, innovative …

Optimal Roof Coverage And Identification Of Potential Roof Problems In Underground Coal Mines Using Led Lighting, James A. Samples

Theses and Dissertations--Mining Engineering

The popularity and implementation of light emitting diode (LED) lighting have increased drastically over recent years into both residential and industrial applications. However, due to MSHA permissibility requirements, LED lighting is not currently being fully utilized in underground coal mining. While previous research has focused on examining the benefits that LED lighting possesses over other common light sources, very few have been done to find the optimum configuration to illuminate underground excavations better for the safety of the miners. In this research, multiple experiments were conducted to evaluate the potential impacts LED lighting can have on underground mine safety. The …

Computational Fluid Dynamics (Cfd) Modeling And Validation Of Dust Capture By A Novel Flooded Bed Dust Scrubber Incorporated Into A Longwall Shearer Operating In A Us Coal Seam, Ashish R. Kumar

Theses and Dissertations--Mining Engineering

Dust is a detrimental, but unavoidable, consequence of any mining process. It is particularly problematic in underground coal mining, where respirable coal dust poses the potential health risk of coal workers’ pneumoconiosis (CWP). Float dust, if not adequately diluted with rock dust, also creates the potential for a dust explosion initiated by a methane ignition. Furthermore, recently promulgated dust regulations for lowering a miner’s exposure to respirable coal dust will soon call for dramatic improvements in dust suppression and capture.

Computational fluid dynamics (CFD) results are presented for a research project with the primary goal of applying a flooded-bed dust …

Sustainable Disposal Of Coal Processing Waste Streams, Mohammad Rezaee

Theses and Dissertations--Mining Engineering

Modern coal preparation facilities incorporate a wide array of solid-solid and solid-liquid separation processes for rejecting mineral matter to meet market specifications. The coarse mineral matter is typically placed into engineered refuse piles whereas the fine refuse is either stored in impoundments or co-disposed with the coarse refuse. The discharge water from the refuse material represents an environmental concern due to the potential release of trace elements, and the subsequent elevation of total dissolved solids and conductivity. The research findings reported in this dissertation addresses sustainable coal processing waste disposal through using strategies aimed at minimizing the environmental impacts. To …

Determination Of Explosive Energy Partition Values In Rock Blasting Through Small-Scale Testing, Joshua Calnan

Theses and Dissertations--Mining Engineering

Blasting is a critical part of most mining operations. The primary function of blasting is to fragment and move rock. For decades, attempts have been made at increasing the efficiency of blasting to reduce costs and increase production. Most of these attempts involve trial and error techniques that focus on changing a single output. These techniques are costly and time consuming and it has been shown that as one output is optimized other outputs move away from their optimum level. To truly optimize a blasting program, the transfer of explosive energy into individual components must be quantified. Explosive energy is …

Korean Anthracite Coal Cleaning By Means Of Dry And Wet Based Separation Technologies, Majid Mahmoodabadi

Theses and Dissertations--Mining Engineering

Korean coals are typically high rank anthracite characterized by high ash content and difficult cleaning characteristics. The main objective of the study was to evaluate the feasibility of treating various size fractions within the coal using an assortment of physical coal cleaning technologies. Dry cleaning is preferred due to the friability of the coal. As such, three pneumatic processes were tested including Ore Sorting for the plus 10 mm material, Air Table Separation for 10 x 1 mm fraction and Tribo-electric Separator for - 1 mm fraction. The Dense Medium Cyclone is known to be one of the most efficient …

Pilot Scale Demonstration And Evaluation Of Innovative Non-Deslimed Non-Classified Gravity-Fed Hm Cyclone, Yumo Zhang

Theses and Dissertations--Mining Engineering

Coal preparation plants are required in some cases to produce a high-grade product using a low specific gravity cut-point. For these situations, a second higher gravity separation would be desirable to generate a mid-grade product that can be utilized for electricity generation thereby maximizing coal recovery. A study was conducted to evaluate the potential of achieving efficient separations at two different density cut-points in a single stage using a three-product dense medium cyclone. Variations in density cut-point and process efficiency values were quantified as a function of the feed medium density, feed medium-to-coal ratio, and feed pressure using a three-level …

Total Cost Optimization For Contour Blasting In The Appalachia Region, Brett Christopher Jackson

Theses and Dissertations--Mining Engineering

This thesis recounts the study of contour blasting practices in the Appalachia coal region. Contour blasting practices vary widely and problems are often encountered. Several different sites were visited and contour blasting practices at each were studied. Based on the information gathered, a comprehensive plan was developed for blasting operations to follow and then was tested and compared to an example of blasting practices without use of the plan. The blasting practices were compared by examining monthly production rates as well as a time study to measure the efficiency a contour blast could be loaded and hauled away and a …

Analysis Of The Armps Database Using Flac3d; A Pillar Stability Comparison For Room And Pillar Coal Mines During Development, Ali Soltani

Theses and Dissertations--Mining Engineering

Designing a safe and economical mining activity is the main goal of every mine design engineer. With the rise of computer modeling in mine design there is a need for a standardized method to use geologic characterization of rocks in engineering design. In this research, first a review of empirical methods will be conducted and after that a step-by-step method is presented to adequately use FLAC3D, for development pillars, in room and pillar mine in development stage. ARMPS database is used to evaluate the FLAC3D model results. ARMPS database consists of 645 case study in room and pillar mines. 170 …

Static And Dynamic Discrete Element Modelling Of Slender Coal Pillars, Michael J. Raffaldi

Theses and Dissertations--Mining Engineering

Highwall mining is a mining method used in surface coal operations that involves driving a series of parallel entries into the exposed coal seam at the highwall face under an unsupported roof leaving behind a series of long, but very slender coal pillars. Highwall mining often occurs simultaneously with production blasting taking place in other areas of the mine. Although no failures of highwall pillars have been attributed to nearby blasting, numerical modelling presents an inexpensive means of investigating the possible effects of strong ground motion on the stability of these pillars. This thesis documents the development of a discrete …

Improved Understanding Of Coal Pillar Behavior And Bump Potential Through The Ground Response Curve, Kevin W. Harris

Theses and Dissertations--Mining Engineering

Continued depletion of easier coal reserves has necessitated development at deeper overburdens. At greater depth, operations often encounter more difficult ground conditions due to higher stresses and potential multiple seam interactions. Pillars which are left intact as the primary support mechanism experience an increase in loading. Mine design improvements are often incorporated to combat increased loads, principally by increasing pillar size. However, the potential for coal bumps, which are a rapid and violent failure of coal pillars, has increased due to these higher stresses and the use of larger width-to-height (W/H) ratio pillars.

Many efforts have been made to predict …

Active Current Injection Method For Limiting Ground Fault Current Harmonics In Underground Coal Mines, Yigong Zhang

Theses and Dissertations--Mining Engineering

Current practice in U.S. underground coal mine high-voltage distribution systems is to attempt to limit ground fault current to 25 Amperes and de-energize the circuit at 10 Amperes. However, the significant amount of system capacitance due to the use of shielded cables can cause ground fault current to be two or three times the intended ground fault limit. Consequently, this practice can cause several issues such as ground fault currents significantly exceeding the neutral grounding resistor current limit, loss of relay selectivity in the distribution system, and transient overvoltages in certain ground fault situations. These issues are solved to some …

Ultra Clean Coal Production Using Dense Medium Separation For The Silicon Market, Seyed Hassan Amini

Theses and Dissertations--Mining Engineering

The production of high quality silicon requires the use of ultraclean coal containing less than 1.5% ash. The magnetite used to clean the coal in a dense medium process is a contaminant that seriously impacts the quality of the final silicon product. As such, research has been conducted to evaluate the potential to substitute the magnetite with fine silica–based alternative material generated during the silicon production process. Dense medium cyclone tests were performed based on a statistically designed program to determine the optimum conditions that maximize organic efficiency and minimize probable error and low–density bypass. The results revealed that a …

Status Of Communication And Tracking Technologies In Underground Coal Mines, Alexander D. Douglas

Theses and Dissertations--Mining Engineering

In 2006, Congress passed the MINER Act requiring mine operators to submit an emergency response plan that included post-accident communications and tracking systems to MSHA within three years of the Act. These systems were required to be designed for maximum survivability after a catastrophic event, such as a fire or explosion, and to be permissible (meets MSHA criteria for explosion-proof). At that time, no commercially available systems existed that met these standards. Several companies undertook developing new, or enhancing existing, technologies to meet these requirements. This research presents the results of a study that was conducted to determine the present …

Multiscale Modeling Of The Mine Ventilation System And Flow Through The Gob, William Chad Wedding

Theses and Dissertations--Mining Engineering

The following dissertation introduces the hazard of methane buildup in the gob zone, a caved region behind a retreating longwall face. This region serves as a reservoir for methane that can bleed into the mine workings. As this methane mixes with air delivered to the longwall panel, explosive concentrations of methane will be reached.

Computational fluid dynamics (CFD) is one of the many approaches to study the gob environment. Several studies in the past have researched this topic and a general approach has been developed that addresses much of the complexity of the problem. The topic of research herein presents …

Development Of Industry Oriented Cfd Code For Analysis / Design Of Face Ventilation Systems, Todor P. Petrov

Theses and Dissertations--Mining Engineering

Two of the main safety and health issues recognized during deep cut coal mining are methane and dust hazards. Advances in continuous miner technology have improved safety and productivity. However, these advances have created some environmental problems, notably more dust and methane being generated at the face during coal extraction.

Results of studies performed in the last three decades concerning the face ventilation for deep cut mining showed very complicated airflow behavior. The specifics of flow patterns developed by the face ventilation systems presents significant challenge for analytical description even for equipment-free entry. Fortunately, there are methods, such as numerical …

Fragmentation Analysis In The Dynamic Stress Wave Collision Regions In Bench Blasting, Catherine E. Johnson

Theses and Dissertations--Mining Engineering

The first step in many mining operations is blasting, and the purpose of blasting is to fragment the rock mass in the most efficient way for that mine site and the material end use. Over time, new developments to any industry occur, and design and implementation of traditional techniques have to change as a consequence. Possibly the greatest improvement in blasting in recent years is that of electronic detonators. The improvements related to safety and increased fragmentation have been invaluable. There has been ongoing debate within the explosives industry regarding two possible theories for this. Shorter timing delays that allow …

Evaluation Of Overpressure Wave Transition By Airblast Overpressure And Shock Wave Attenuation Analysis Using A Small Black Powder Charge, William R. Weitzel

Theses and Dissertations--Mining Engineering

Eight flush mount pressure sensors were used in a series of 3 test sequences to measure air overpressure produced by a firecracker. Overpressure was recorded at a range of 1 inch to 21 inches away from detonation, and charge weight was determined to be 0.1mg of black powder. Air overpressure prediction equations were developed from test series then compared to collected data for subsequent tests. Overpressure wave velocity was measured using wave arrival time and distance between sensors. This wave velocity was compared to calculated wave velocity using overpressure and ideal gas law. Overpressure and wave velocity are directly related …

Development Of 15 Psi Safe Haven Polycarbonate Walls For Use In Underground Coal Mines, Rex Allen Meyr Jr.

Theses and Dissertations--Mining Engineering

Following three major mining accidents in 2006, the MINER Act of 2006 was enacted by MSHA and required every underground coal mine to install refuge alternatives to help prevent future fatalities of trapped miners in the event of a disaster. The following research was performed in response to NIOSH’s call for the investigation into new refuge alternatives. A 15 psi safe haven polycarbonate wall for use in underground coal mines was designed and modeled using finite element modeling in ANSYS Explicit Dynamics. The successful design was tested multiple times in both half-scale and small scale using a high explosive shock …

Experimental Comparison Study Of The Response Of Polycarbonate And Laminated Glass Blast Resistant Glazing Systems To Blast Loading, Joshua Calnan

Theses and Dissertations--Mining Engineering

This thesis recounts the experimental study of the dynamic response of polycarbonate blast resistant glazing systems to explosive loading through the use of triaxial load cells, pressure sensors, and a laser displacement gauge. This instrumentation captured the response of the glazing systems to blast loading over three phases of testing. The first phase of testing characterizes the load distribution around the perimeter and the second phase examines the repeatability of the results. The final phase of testing pushes the samples to failure. The results are then compared to HazL, a commonly used blast resistant glazing system analysis software tool. The …

Modeling Of An Air-Based Density Separator, Tathagata Ghosh

Theses and Dissertations--Mining Engineering

There is a lack of fundamental studies by means of state of the art numerical and scale modeling techniques scrutinizing the theoretical and technical aspect of air table separators as well as means to comprehend and improve the efficiency of the process. The dissertation details the development of a workable empirical model, a numerical model and a scale model to demonstrate the use of a laboratory air table unit.

The modern air-based density separator achieves effective density-based separation for particle sizes greater than 6 mm. Parametric studies with the laboratory scale unit using low rank coal have demonstrated the applicability …

A Framework For Understanding The Public's Perspectives Of Mining Applied To The Kentucky Coal Industry, Joshua M. Hoffman

Theses and Dissertations--Mining Engineering

People’s perceptions of mining are heavily based on the media they consume and the messages therein. News outlets ordinarily report on mining only when there is an accident or environmental concern. When messages that the public is exposed to are negative, it is no wonder that there are negative perceptions about mining.

Current public relations campaigns on the behalf of specific companies or select sectors do exist; however, this is often a reactionary move in response to recent shifts in the socio-political environment. The details of these campaigns are often tied up in proprietary information or withheld by public relations …

Characterizing The Variability In Respirable Dust Exposure Using Johnson Transformation And Re-Examining 2010 Proposed Changes To The U.S. Underground Coal Mine Dust Standard, Al I. Khan

Theses and Dissertations--Mining Engineering

Coal workers’ pneumoconiosis (CWP), commonly referred to as black lung, is a chronic lung disease that results from the inhalation and deposition of coal dust in the lungs. While this disease continues to afflict coal miners, its prevalence has steadily declined over three decades since 1970. Based on a voluntary X-ray surveillance program, conducted by the National Institute for Occupational Safety and Health (NIOSH), this downward trend, however, ended in 2000 and has actually begun to rise. The Mine Safety and Health Administration (MSHA) instituted a Comprehensive Initiative to “End Black Lung” to combat the reported upturn in black …