Engineering Commons^™

Numerical Study On Scaling Effects And Decoupled Network-Based Simulation Of Gaseous Explosion, Liang Wang

Doctoral Dissertations

"This research seeks to improve the prediction efficiency of gaseous explosions realized by numerical simulations in a full-scale underground network using a decoupled method. To provide quick predictions of overpressure distribution of methane explosions in underground airway networks, a two-section theory is employed. The explosion space is divided into a driver section and a blast-wave section. Governing equations including conservation of mass, momentum, and energy, together with chemical reaction and turbulence models are solved for the driver and the blast-wave sections using computational fluid dynamics (CFD) solver ANSYS Fluent (3D-based) and Flowmaster (1D-based) respectively. The three dimensional (3D) and one …

The Effects Of Physical Flash Hole Deviations On Factory-Grade Rifle Ammunition, Nicolaas Martin Schrier

Masters Theses

"The objective of this research is to determine the effect of dimensional and positional changes of the primer flash hole on the performance of factory-grade rifle ammunition. The studied variables were flash hole diameter, offset from center, and orientation of the offset in the primer pocket. Cartridge performance was quantified by measuring muzzle velocity, chamber pressure, and target grouping size (precision).

Five different flash hole diameters were tested for both the Remington .223 and Winchester .308 calibers: 1.4mm, 2.0mm (the Fiocchi standard), 2.4mm, 2.8mm, and 3.0mm. Each diameter was tested at three offsets: centered (no offset), 0.5mm from center, and …

The Relative Effect Of Charge Dimensions On Elastic Vibration Attenuation And Blast-Induced Seismic Energy Concepts, Nathan Thomas Rouse

Doctoral Dissertations

"This dissertation focuses on expanding the blasting industry's current understanding of the effect of charge geometry on blast vibration attenuation. The work includes a multiple regression analysis of a sample population of signature hole blast vibration data. The regression analysis is used to identify the relative effect of the variables that affect blast vibrations at various distances from the charge. The study suggests that the most common vibration models used in the blasting industry do not use all of the statistically significant variables. Therefore, the models neglect to fully describe the relationship between the significant variables and the blast vibration. …

Detecting Diesel Particulate Matter Using Real Time Monitoring Under The Influence Of An Exhaust Fan System, Yasir Helal Alghamdi

Masters Theses

"Diesel Particulate Matter (DPM) is a complex mixture of diesel exhaust gas that consists of carbon, ash, metallic abrasion particles, sulfates and silicates. The diesel soot particle includes a solid core made of elemental carbon, and organic carbon compound attached to the surface of the soot particle. The main source of DPM is diesel exhaust gas. The National Institute for Occupational Safety and Health (NIOSH) and the Environmental Protection Agency (EPA) have determined that DPM is the source of most of the emissions of carbon monoxide, carbon dioxide, oxide of nitrogen, and hydrocarbons in underground coal, metal and non metal …

Studies On The Role Of Organic-Inorganic Hybrid Polyacrylamides In Fine Coal Flotation, Ontlametse Kenneth Molatlhegi

Masters Theses

"The current study investigated the effect of novel organic/inorganic (hybrid) polyacrylamide polymer as ash (slimes) depressant in fine coal flotation for the possibility to enhance the combustible recovery and ash rejection. Raw coal samples contain about 25% of ash-forming minerals were crushed, grinded to -75um and floated in the presence of in-house synthesized hybrid Polyacrylamide (Al(OH)₃-PAM or Al-PAM) at different operational parameters. Denver flotation cell with a 5-Liters capacity was used and the parameters investigated include: Al-PAM dosage, Al-PAM conditioning time, dual use of Al-PAM and a dispersant, impeller rotation speed and pulp's pH. For comparison purposes, commercially …

A Novel Powder Factor Based Bench Blast Design Method For Large Surface Coal Mines, Andrew Clifford Blair

Doctoral Dissertations

"Large surface coal mines in Wyoming's Powder River Basin ship millions of tons of coal per annum, moving millions of cubic yards of overburden to mine the coal. Much of this volume is blasted in the form of benches, a common mining technique. Increases in production and scale of equipment in the past thirty-five years have created a paradigm shift for drill and blast personnel at these large surface mines, and the explosives industry has yet to create a blast design method specifically tailored for large surface coal mine bench blasting.

This research examines the typical scale of bench blasting …

The Impact Of A Strong Local Supply Chain On Regional Economic Impacts Of Mining, Meiyu Xing

Masters Theses

"With growing social conflicts due to social and environmental concerns mines need to be able to create shared value for all stakeholder in their quest to promote sustainable development. Given the sensitivity of a mine's regional economy contribution to its supply chains, any improvement in supply chains strategy will be beneficial for mines and their stakeholders. The objectives of this work were to: (i) test the hypothesis that supply chain management strategy, by mines in a region, significantly affects regional economy; and (ii) develop a methodology to identify the critical backward commodities of a regional mining sector.

Valid methods have …

Microstructure And Geotechnical Properties Of St. Peter Sandstone In Clayton, Iowa, Amir Hossein Bagherieh

Doctoral Dissertations

"The St. Peter Sandstone is significantly different from the minerals and rocks which have been studied extensively in mining. It is brittle and characterized by an unusually high friction angle. On the other hand it is friable, and it is nearly cohesionless. The scarcity of the ground control techniques for this particular mining environment has created many difficulties for mine operators. This research aims to establish a fundamental understanding of the basic mechanical and strength properties of the St. Peter Sandstone for engineering design and scientific research. The specific objectives are 1) characterizing the strength of the St. Peter Sandstone, …

Describing Local Community Acceptance With Discrete Choice Theory For Enhanced Community Engagement, Sisi Que

Doctoral Dissertations

This research sought to facilitate improved community (stakeholder) analysis by providing further insight on the determinants of local community acceptance using discrete choice theory. Specifically, the goals were to: (1) Identify, classify, and verify the important project characteristics and key demographic factors which affect local community acceptance of a mining project; (2) Account for the large number of relevant factors inherent in discrete choice experiments for mining community acceptance evaluation; and (3) Examine discrete choice models to select the most appropriate model for mining community consultation. The research will test the hypotheses that various discrete choice models can describe the …

Analysis Of Effects Of Surface Roughness And Local Surface Imperfections On Measured Pressure, Laurin Ashley Bookout

Doctoral Dissertations

"When tests using pressure to characterize the performance or effects of an explosive are conducted in laboratory or other small scale, highly controlled settings, it is expected that any gages will be ideally mounted and there will not be any surface imperfections or roughness near the gage location. However, when explosive tests are scaled up, the test beds typically do not have perfect surfaces. Instead there may be rough surfaces with various types of geometry or situations where it is extremely difficult to get the gage flush mounted with a flat surface. In a time where tests with multiple replications …

The Effects Of Short Delay Times On Rock Fragmentation In Bench Blasts, Margaret Ruth Hettinger

Masters Theses

"Optimized rock fragmentation is essential for minimizing downstream costs to mining operations. Photographic fragmentation analysis, vibration monitoring, and high-speed video all provide measurements of blast effectiveness and supply data that allows operations to modify blasts to achieve downstream goals.

This study evaluates the effects of short hole-to-hole delay times on rock fragmentation. Photographic fragmentation analysis and various delay times were used on the same bench blast, the effects of timing on fragmentation were determined. This analysis provides a representative understanding of timing effects on fragmentation in the field, different from previous blast models which either negate the effects of timing …