Mining Engineering Commons^™

A Novel Method For Sensorless Speed Detection Of Brushed Dc Motors, Ernesto Vazquez-Sanchez, Joseph Sottile, Jaime Gomez-Gil

Mining Engineering Faculty Publications

Many motor applications require accurate speed measurement. For brushed dc motors, speed can be measured with conventional observers or sensorless observers. Sensorless observers have the advantage of not requiring any external devices to be attached to the motor. Instead, voltage and/or current are measured and used to estimate the speed. The sensorless observers are usually divided into two groups: those based on the dynamic model, and those based on the ripple component. This paper proposes a method that measures the current of brushed dc motors and analyses the position of its spectral components. From these spectral components, the method estimates …

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 …

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 …

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 …

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 …

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 …