Explosives Engineering Commons^™

The Effect Of Delay And Sequence On Blasting Fragmentation Results, Tristan Worsey

Theses and Dissertations--Mining Engineering

Blasters use the delay between charges and the firing sequence of the explosive charges to help reduce vibrations and achieve the desired fragmentation. Although delay and sequence are recognized as very important for vibrations and fragmentation, only vibration models consider timing as a variable in the prediction tool, without any known model for fragmentation prediction based on the delay sequence. Of the few fragmentation models available, very few take delay into account and do not give guidance on row delay and/or sequence selections. With the invention of electronic detonators in 1984, there are new avenues to explore with sequence and …

Shock Wave Propagation Behavior At Corners And Crosscuts In Five Small-Scale Tunnel Scenarios, David Pierre Doucet

Masters Theses

"Shock wave propagation in tunnels and other enclosed environments is substantially more complicated than in an open-air or even a surface detonation. There is still much to learn about how shock wave properties change as a wave propagates in an enclosed space, such as a mine tunnel, inside of a building, or city street. The geometry of the enclosure will have a large role in the propagation of the shock wave. This means that many different tunnel designs must be studied. This work tested five different designs using a modular small-scale model. The scenarios tested were Straight-line, Single Turn, Around …

Additive Manufacturing Of Linear Shaped Charges To Address Run Up And Run Down Phenomena, Jason Ho

Masters Theses

”A shaped charge is an explosive device used to focus detonation energy in a desired direction. Additive Manufacturing (AM) can allow greater design freedom and geometric complexity for the liner portion of the shaped charge.

In this work, the following hypotheses were tested: 1) Adjusting the initial apex angle of a linear shaped charge liner reduces the amount of run up that occurs, and 2) implementing a backstop at the end of a linear shaped charge liner reduces the amount of run down that occurs.

Linear shaped charge liners with a continuously changing apex angle were created with additive manufacturing. …

Fundamental Limits To The Transfer Of Energy Harvested From Ferroelectric Materials Under Shock Loading, Sergey I. Shkuratov, Jason Baird, Vladimir G. Antipov, Jay B. Chase

Mining Engineering Faculty Research & Creative Works

Ferroelectrics are capable of producing megawatt power levels under shock loading due to stress-induced phase transformations, resulting in depolarization of the ferroelectric materials. This power can be used for generation of high voltages, high currents, or ultrahigh-power electromagnetic radiation. The results are reported herein on an experimental study of limitations on energy harvested from shocked Pb_0.99(Zr_0.95Ti_0.05)_0.98Nb_0.02O₃ and PbZr_0.52Ti_0.48O₃ ferroelectrics and transferred to external electrical systems. The experimental results indicate that one of the limits to the energy transfer is electric breakdown that occurs within …

Multilayer Pzt 95/5 Antiferroelectric Film Energy Storage Devices With Giant Power Density, Sergey I. Shkuratov, Jason Baird, Vladimir G. Antipov, Shujun Zhang, Jay B. Chase

Mining Engineering Faculty Research & Creative Works

A new type of energy storage devices utilizing multilayer Pb (Zr_0.95Ti_0.05)_0.98Nb_0.02O₃ films is studied experimentally and numerically. To release the stored energy, the multilayer ferroelectric structures are subjected to adiabatic compression perpendicular to the polarization direction. Obtained results indicate that electrical interference between layers (10–120 layers) during stress wave transit through the structures has an effect on the generated current waveforms, but no impact on the released electric charge. The multilayer films undergo a pressure-induced phase transition to antiferroelectric phase at 1.7 GPa adiabatic compression and become completely depolarized, releasing surface …

The Dependence Of Breakdown Field Upon Breakdown Delay Time In Adiabatically Compressed Ferroelectric Ceramics, Sergey I. Shkuratov, Jason Baird, Vladimir G. Antipov, Jay B. Chase

Mining Engineering Faculty Research & Creative Works

The ability of ferroelectric materials to generate high voltage under mechanical stress is widely used in transducer applications. The high strain-rate adiabatic compression of poled ferroelectrics results in their complete depolarization, the release of surface charges, and the generation of up to hundreds of kilovolts of electric potential that is an order of magnitude higher than in the low-strain piezoelectric mode. Electric breakdown within adiabatically compressed ferroelectric specimens is one of the factors that affect the generation of a high voltage by ferroelectric materials under extreme stress. We report herein the results of experimental investigations of the generation of high …

Stress-Induced Depolarization Of Single-Layer Pzt 95/5 Ferroelectric Films, Sergey I. Shkuratov, Jason Baird, Vladimir G. Antipov, Jay B. Chase, Wesley Hackenberger

Mining Engineering Faculty Research & Creative Works

Ferroelectric (FE) films are widely used in electronic devices and low-power FE transducers. There is significant interest in expanding the usage of FE films to ultrahigh-power systems. The results are reported herein on experimental investigations of stress-induced depolarization of single-layer PbZr_0.95Ti_0.05O₃ doped 2% Nb (PZT 95/5) poled FE films subjected to uniaxial adiabatic compression perpendicular and antiparallel to the direction of polarization. It was found that at a stress of 2.4 GPa, the 32-μm-thick films underwent a pressure induced transition to a nonpolar antiferroelectric phase and became completely depolarized in both modes of high strain …

Simplifying Techniques Applied To Computational Fluid Dynamics Modeling Of Methane Explosions, Laura Steeves

Theses and Dissertations--Mining Engineering

Traditional methods of studying underground coal mine explosions are limited to observations and data collected during experimental explosions. These experiments are expensive, time-consuming, and require major facilities, such as the Lake Lynn Experimental Mine. The development of computational fluid dynamics (CFD) modeling of explosions can help minimize the need for large-scale testing. This thesis utilized the commercial CFD software, SC/Tetra, to examine three case studies. The first case study modeled the combustion of methane in a scaled shock tube, measuring approximately 1 foot by 1 foot, by 20.5 feet long, with a methane cloud of 2.5 feet in length, at …

Projectile Impact Effects On A 50 Psi Plug Type Coal Mine Seal, Bruce Albert Von Niederhäusern

Masters Theses

"The current lack of projectile damage criteria for mine seals is assessed to determine if criteria should be developed. Impact experiments were performed on a full-scale 50 psi mine seal to determine failure modes, dynamic stress state, and assess risk to existing operational mine seals. Test projectiles were selected from common underground coal mine items propelled by means of a black powder projectile generator. Projectile velocities attained in testing ranged from approximately 100 to 650 ft/s (30 to 200 m/s). Dynamic strain was measured on the non-impact face to derive the state of stress and estimate failure criteria. Penetration models …

Pressure Versus Impulse Graph For Blast-Induced Traumatic Brain Injury And Correlation To Observable Blast Injuries, Barbara Rutter

Doctoral Dissertations

"With the increased use of explosive devices in combat, blast induced traumatic brain injury (bTBI) has become one of the signature wounds in current conflicts. Animal studies have been conducted to understand the mechanisms in the brain and a pressure versus time graph has been produced. However, the role of impulse in bTBIs has not been thoroughly investigated for animals or human beings.

This research proposes a new method of presenting bTBI data by using a pressure versus impulse (P-I) graph. P-I graphs have been found useful in presenting lung lethality regions and building damage thresholds. To present the animal …

The Mechanics Of Precision Presplitting, Anthony Joseph Konya

Doctoral Dissertations

"Precision Presplitting is a widely used method of presplit blasting for the mining and construction industries. In recent years considerable effort has gone into the development of empirical equations based on field data to be able to better design the Precision Presplit for various rock types and structural environments. However, the most widely discussed theory about the mechanics of the presplit formation, that of shockwave collisions, does not appear to be applicable for this method of presplitting.

This research has disproven this theory based on insufficient magnitude of the shockwave from modeling with basic wave mechanics. Other authors have suggested …

The Behavior Of Suas Under Explosive Loading Conditions And Implications For Safe Operating Procedures, Ashok Em Sudhakar

Doctoral Dissertations

"Drones are increasingly being used for tasks previously unimagined and the beneficial uses are evolving. The United States Congress has envisioned the possible uses of drones for both combating and conveying explosive threats and other harmful and destructive activities. Congress' intent is reflected in new laws (2018) and policies (2019).

All civilian available Small Unmanned Aerial Systems sUASs (Drones), weighing less than 55 pounds, in the current market are not designed for operations in explosive environments. This first of a kind research focuses on further understanding of sUASs response to explosive loading and the public policy implications. This research measured …

Additive Manufacturing Of Liners For Shaped Charges, Jason Ho, Cody Lough, Phillip R. Mulligan, Edward C. Kinzel, Catherine E. Johnson

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

A Shaped Charge (SC) is an explosive device used to focus a detonation in a desired direction, and has applications in oil extraction, weaponry and demolition. The focusing relies on a void in the explosive mass, shaped by a metal liner that becomes a super-heated projectile during detonation. Additive Manufacturing (AM) allows greater design freedom and geometric complexity for the liner portion of the SC. Specifically, hierarchical structuring and functional grading can potentially provide greater velocity, directionality, and efficiency. In this work, Selective Laser Melting (SLM) is used to explore different geometries for an SC liner made out of SS …

Process Mineralogy Of Iranian High Sulfur Iron Ore, Tonglin Zhao, Xiaoli Wang, Hongle Ai, Ahmed Sobhy

Mining Engineering Faculty Research & Creative Works

Processing of Iranian high sulfur iron ore is problematic in minerals industry. The iron ores were studied by the means of polarizing microscopy, chemical analysis, X-ray diffraction. The study shows that the iron ores have high grade of iron, and complex structures. XRD showed that the iron ore consists of metallic minerals such as magnetite with a small amount of hematite and limonite and non-metallic minerals as serpentine, chlorite, and talc. The average particle size of magnetite crystals is 0.182 mm. The ore contains 1.62% sulfur as harmful impurity in form of pyrite mineral. Due to the isomorphism of magnesium …

Detonation Synthesis Of Alpha-Variant Silicon Carbide, Martin Langenderfer, Catherine E. Johnson, William Fahrenholtz, Vadym Mochalin

Mining Engineering Faculty Research & Creative Works

A recent research study has been undertaken to develop facilities for conducting detonation synthesis of nanomaterials. This process involves a familiar technique that has been utilized for the industrial synthesis of nanodiamonds. Developments through this study have allowed for experimentation with the concept of modifying explosive compositions to induce synthesis of new nanomaterials. Initial experimentation has been conducted with the end goal being synthesis of alpha variant silicon carbide (α-SiC) in the nano-scale. The α-SiC that can be produced through detonation synthesis methods is critical to the ceramics industry because of a number of unique properties of the material. Conventional …

Complete Stress-Induced Depolarization Of Relaxor Ferroelectric Crystals Without Transition Through A Non-Polar Phase, Sergey I. Shkuratov, Jason Baird, Vladimir G. Antipov, Wesley Hackenberger, Jun Luo, Shujun Zhang, Christopher S. Lynch, Jay B. Chase, Hwan R. Jo, Christopher C. Roberts

Mining Engineering Faculty Research & Creative Works

The development of relaxer ferroelectric single crystal technology is driven by the ability to tailor ferroelectric properties through domain engineering not achievable in polycrystalline materials. In this study, three types of domain-engineered rhombohedral Pb (In_1/2Nb_1/2) O₃-Pb (Mg_1/3Nb_2/3) O₃-PbTiO₃ crystals were subjected to transverse high strain rate loading. The experimental results indicate that the domain configuration has a significant effect on the stress-induced depolarization and the associated charge released. A complete depolarization of the single-domain crystals with 3m symmetry is observed, while multidomain crystals with 4mm and mm2 …

Impact Of Nanobubbles On Mechanical Coal Flotation Process, Ahmed Sobhy, Dongping Tao

Mining Engineering Faculty Research & Creative Works

A bank of three 10-liter mechanical flotation cells integrated with nanobubble technology was investigated to assess the impact of nanobubbles on coal separation performance at different operating variables. The most significant operation parameters such as fuel oil collector dosage, methyl isobutyl carbinol (MIBC) frother concentration, flow rate to nanobubble generator, feed solid concentration, and feed flow rate were studied individually. Nanobubbles are generated selectively on the hydrophobic particles, which should have a positive effect on flotation separation efficiency. It has been shown that frother concentration, collector dosage, and flow rate to nanobubble generator had a positive and significant effect on …

Analysis Of Underground Coal Mine Structures Subjected To Dynamic Events, Brooklynn Yonts

Theses and Dissertations--Mining Engineering

Underground coal mine explosions pose a significant threat to infrastructure such as mine seals and refuge alternative chambers. After a mine seal failed in the Sago mine disaster, which took the life of 12 miners, design requirements were reexamined and improved. However, most research being completed on the analysis of mine structures during an explosive event focuses solely on peak pressure values, while ignoring the impact of pressure duration. This study investigates the impact pressure duration, waveform shape, and impulse have on structural displacement, while also exploring what pressures and duration can be expected during a mine explosion. Additionally, the …

Management Of Coal Dust Explosions In United States' Coal Mines Using Bag Type Passive Explosion Barriers, Jay Robert Schafler

Masters Theses

"The most significant and powerful hazard that exists in an underground coal mine is a coal dust explosion. A coal dust explosion has the potential to propagate throughout a mine resulting in massive damage to the mine and equipment, as well as tragic loss of life. An assessment of current global regulations and practices uncovered four main control methods utilized to prevent coal dust explosions in coal mines world-wide. The United States is one of the few countries that does not regulate or employ all four of these safety practices. Additionally, a review of past research into coal dust explosions …

Shockwave Interaction With A Cylindrical Structure, Phillip R. Mulligan

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

An increased understanding of the shockwave interaction with a cylindrical structure is the foundation for developing a method to explosively seal a pipe similar to the Deepwater Horizon accident in the Gulf of Mexico. Shockwave interactions with a cylindrical structure have been a reoccurring focus of energetics research. Some of the most notable contributions of non-destructive tests are described in ``The Effects of Nuclear Weapons'' (Glasstone, 1962). The work presented by Glasstone examines shockwave interaction from a 20-megaton bomb with a cylindrical structure. However, the data is limited to a peak overpressure of less than 25 psi, requiring several miles …

Effect Of Explosive Charge Geometry On Shockwave Propagation, Catherine E. Johnson, Phillip R. Mulligan, Kelly Williams, Martin Langenderfer, Jeffrey Heniff

Mining Engineering Faculty Research & Creative Works

With advancements in the 3D printing of explosives, the understanding how the shape of an explosive charge influences the energy expansion and subsequently the focusing of energy is becoming increasingly more important. Theoretically, explosive charges could be printed to focus the energy on targets of interest or to synthesize nanomaterials. The first step to quantifying the energy expansion and shock wave convergences for a 3D printed charge is to examine simple geometries of traditional explosive charges (non-3D printed). Detonation of 15 PETN-based primasheet charges in the spherical, cubic, cylindrical, and tetrahedral configurations have been examined in this study. Qualitative data …

The Influence Of Caprock On Blast Fragmentation Distribution, Matthew Kurtis Coy

Doctoral Dissertations

"This dissertation describes the development of a small-scale model of a caprock-laden quarry blast and discusses the results from that testing. The purpose of this testing was to provide insight into the reasons for poor caprock breakage during blasting.

Small-scale test blocks were poured using a weak mortar mix to represent a limestone formation at a small scale. A cold joint was created in the upper portion of the test specimens to represent the bedding plane that separates caprock and substrate layers in a caprock-laden limestone bench. The scale-model test blocks were blasted using detonating cord. The primary configuration for …

Material Properties Affecting The Penetration Of Metal Targets By Copper Linear Shaped Charges, Kevin Lee Phelps

Masters Theses

"A linear shaped charge (LSC) is an explosive device used in demolition, aerospace, and in other applications that require the cutting of metal. Users of LSC's typically know the size of shaped charge needed to cut their target but commonly encounter previously untested materials. The motivation for this thesis is to provide an understanding as to what target material properties are good indicators of cutting performance so the selection of LSC can be more efficient. The author found that penetration theories for other types shaped charges were insufficient for the LSC, possibly because of the relatively slow projectile created by …

Modeling Explosive Lensing On A Cylindrical Body In Air: A First Step Towards Sealing An Underwater Offshore Oil Spill, Phillip R. Mulligan

Doctoral Dissertations

"In 2010, the British Petroleum (BP) Deepwater Horizon accident leaked oil into the Gulf of Mexico for 87 days. A fast response method that can seal an oil pipe and stop the release of oil is needed in order to prevent future oil leaks from turning into ecological and financial disasters. Explosives can serve this need.

This research examined how a circular implosive discontinuous explosive lens interacts with a cylindrical surface. The following research was designed to study the applicability of the Method this author developed to predict the peak pressure from multiple shockwaves converging on a centrally located cylinder. …

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 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 …

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 …

Depolarization Mechanisms Of Pbzr0.52ti0.48o3 And Pbzr0.95ti0.05o3 Poled Ferroelectrics Under High Strain Rate Loading, Sergey I. Shkuratov, Jason Baird, Vladimir G. Antipov, Evgueni F. Talantsev, Hwan R. Jo

Mining Engineering Faculty Research & Creative Works

Stress-induced and thermal-induced depolarization studies along with X-ray diffraction were performed on lead zirconate titanate ferroelectrics of different compositions, PbZr_0.52Ti_0.48O₃ (PZT 52/48) and PbZr_0.95Ti_0.05O₃ (PZT 95/5). Specimens were shocked loaded perpendicular to the polarization vector. It was found that the polarity of the stress-induced charge released by PZT 52/48 and 95/5 was opposite to the polarity of the charge generated due to the piezoelectric effect. PZT 52/48 was only partially (45%) depolarized under 1.5±0.1 GPa mechanical compression, as opposed to PZT 95/5 which was fully depolarized. The experimental results indicate …

An Analysis Of Burn Cut Pull Optimization Through Varying Relief Hole Depths, Michael Robert Allen

Masters Theses

"In underground blasting, the pull of the initial cut is the limiting factor for the success of the rest of the round. By improving the pull of the first cut, a critical step is made towards improving the entire round. This project attempted to optimize a burn cut's effective pull by varying the depths of the relief holes in the burn, and then analyzing the results. In testing, relief holes were drilled to depths both shorter and longer than that of the cut's charged holes. The overall objective was to consistently achieve greater pull than in a standard burn, using …

Innovative Rts Technology For Dry Beneficiation Of Phosphate, Ahmed Sobhy, Daniel Tao

Mining Engineering Faculty Research & Creative Works

The Crago double flotation process is widely used for upgrading raw phosphate in Florida. However, it is a water-based physicochemical process and consumes a huge amount of water and chemicals and is not efficient to remove dolomite from phosphate. In addition, the final phosphate flotation concentrate often has a grade of 30-31% P2O5, which is below the BPL content of 75% (or 34.3% P2O5) required for making the animal feed grade phosphate. This study is performed to evaluate the potential and feasibility of the innovative rotary triboelectrostatic separator (RTS) as a dry phosphate beneficiation process. The RTS technology is characterized …