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By Josephine Bones, Robb Larson, Daniel Miler

Avalanches are commonly mitigated through the use of explosives at ski resorts and above transportation corridors. Surprisingly, very little research has been conducted on snowpack response to explosive inputs, and efforts to model this response have been limited. The purpose of this ongoing research project is to ascertain an understanding of the dynamic snowpack response in relation to explosive size and height above the snowpack, coupled with snow conditions, to enhance avalanche control. A system of sensors and computer-controlled data acquisition components has been created to record the movement of snow resulting from the charge detonation. The system records acceleration vertically and radially within the snowpack at two distances from the point of detonation as well as blast air pressure at one location during explosive events. The data at two locations allows inferences to be made about the transmittance and attenuation of shock waves through the snowpack radially as well as vertically. The data shows that raising charges above the surface results in increased snowpack dynamic response when compared to surface detonations. Applying power function regression to accelerations for individual charge elevations, it was determined that both radial and vertical rates of attenuation were not dependant on charge elevation. Additionally, raising the charge also resulted in increased dynamic response at depth within the snowpack

Jan 1, 2012

By Bethany Witter, Dyno Nobel

In the past decades, a technological explosion has caused generational shifts. First, millennials experienced a technological shift to computers and cellphones. Next, Generation Z experienced a shift to smart phones and social media. These two generations are immersed in technology and are accustomed to constant connectivity. How do the extractive and construction industries gain the interest of younger generations and integrate them into the industry?

Feb 1, 2020

By Neal Lee

Reduced relief horizontally means an increase in energy expended vertically into the rock surrounding the stemming column, and potentially through the stemming column. The vast majority of holes in any surface blasting operation are afforded two horizontal relief faces at the moment of firing, whether by existing relief faces in front of and to one side, or previously blasted hole(s) in front of and to one side of the holes in question. When the energy expended in any hole on the blast pattern has less than two Horizontal Relief Planes or faces (referred to moving forward here as “HRPs”) available to it at the moment of firing, a higher percentage of the available energy is directed vertically. In the analysis of recorded videos by the author, one will note the fact that stemming ejection/flyrock is observed to a much greater degree from the center of almost all patterns when they are timed to “pull out of the middle” (“box cut" timed patterns). This is because the first hole to fire in each row has only one Horizontal Relief Plane, which significantly decreases horizontal avenue for energy release for these holes. This of course results in an increase in the amount of energy expended vertically. This paper proposes a novel methodology to modify the stemming to better use the explosives energy of each hole, while controlling side effects such as flyrock and airblast.

Feb 6, 2023

By Bethany Witter

In the past decades, a technological explosion has caused generational shifts. First, millennials experienced a technological shift to computers and cellphones. Next, Generation Z experienced a shift to smart phones and social media. These two generations are immersed in technology and are accustomed to constant connectivity. How do the extractive and construction industries gain the interest of younger generations and integrate them into the industry? The Virginia Tech Student Chapter of the International Society of Explosives Engineers handled this same issue with its recruitment efforts and event planning from 2017-2019. The first critical component of integrating Generation Z college students into the extractive industries is clear and frequent communication via email. Next, Generation Z often values the motivation behind work when choosing a career, so advertising technological advancements, benefits, and ways people can contribute to improving the industry also helps attract young generations. Similarly, advertising opportunities for people to work outside with their hands, travel, and secure stable careers can attract students. At Virginia Tech, the most effective way to attract and maintain the interest of students in extractive industries is to put the students in the field. Field trips to mines and factories experienced the most stable attendance and highest survey reviews of all other chapter events. Guest presentations from industry professionals were often well attended, but attendance tapered off as the academic year progressed and students grew busier. Periodic trips throughout the year maintained student engagement and often supplemented their curriculum. The student chapter was relatively successful in attracting students, but it struggled to maintain attendance levels in the latter portion of the academic year. In the future, the industry can increase its recruitment of Generation Z and Millennials into the workforce by working more closely with university programs to provide resources and opportunities for hands-on experiences for students.

By S A. Steyn, I P. Douglas

Duvha Opencast is a large South African dragline operation supplying coal to the Duvha Power Station which is operated by Eskom, the state power utility. For Duvha to remain competitive with other collieries, it has proved necessary to continuously examine and investigate methods of reducing costs. With explosives representing a major portion of the total working costs, blasting is an obvious area of investigation.

Jan 1, 1991

By John Manka

Emulsion manufactures often spot buy the diesel fuel used in their fuel phases from various sources. Because their diesel source changes, there can be large fuel variation which may affect the quality of the resulting emulsions. This paper shows that the diesel fuel used in manufacturing emulsion explosives has a significant impact on emulsion stability and that the fuel additives dosed into the diesel fuel as it is made also have an impact on the emulsion characteristics and stability. We found that fuels with higher distillation ranges improve emulsion stability. We also found that while none of the diesel fuel additives affected the initial formation of the emulsion, some fuel additives did affect the characteristics and stability of the emulsions as measured by emulsion viscosity, droplet size, high and low shear testing, bin storage testing and freeze thaw cycling.

Jan 1, 2002

By Scott G. Giltner, Paul N. Worsey

During the short duration of an explosive blast, many events occur which are too quick to be detected or observed in detail with the naked eye or by normal photographic techniques. Through the use of "hightech", high speed video, many of these events can be observed, instantly played back and recorded for later use. The use of a Spin Physics SP 2000 Motion Analysis System at a blast casting operation is presented. The variable range of recording speeds offered by the SP 2000 allowed it to be used for examination of different areas of blasts. At its maximum full frame rate of 2000 frames per second the SP 2000 can easily pick up the flame front as it travels down a nonel tube and the flash from the surface delays as they fire. The system was used for a variety of tasks including, but not limited to,the determination of delay accuracy to within 0.5 ms, the velocity and trajectory of the faces during blasts, and pinpointing geological problem areas. The effectiveness of the system as used on site is discussed along with detailed method of set up, recording, playback and data processing. Other details including site specific environmental and lighting problems are also covered.

Jan 1, 1986

By Marilena Cardu, Mauricio Dompiri, Jacopo Seccatore

Blasting in geological bodies is an industrial process acting in an environment characterized by high uncertainties (natural joints, faults, voids, abrupt structural changes), which are transposed into the process parameters (e.g. energetic transfer to rock mass, hole deviations, misfires, vibrations, fly-rock...). The approach to this problem searching for the “optimum” result can be ineffective. The geological environment is marked out by too many uncertainties, to have an “optimum” suitable to different applications. Researching for “Robustness” in a blast design gives rise to much more efficiency. Robustness is the capability of the system to behave constantly under varying conditions, without leading to unexpected results. Since the geology varies from site to site, and often from bench to bench on each site, setting a robust method can grant better results in varying environments, lowering the costs and increasing benefits and safety.

Jan 1, 2011

By E. McCullough, D. Preece, M. Ortel

The mining and oil industries employ techniques such as geologic mapping, core drilling and electromagnetic field techniques to explore for new deposits. New discoveries of major near-surface ore bodies are becoming progressively rare and traditional exploration methods are unable to resolve ore bodies deeper than about 500 m (1640.4 ft). Consequently high-resolution seismic reflection techniques show great potential for exploration to much greater depths down to almost 3 km (1.9 mi).

Jan 1, 2013

By K. Hausmann, P. A. Sashin, G. J. Prejean

Misfires caused by unreliable shock tube constructions can have significant cost implications and place field workers at serious risk during remediation. Ionomer materials, used as a subtube in shock tube constructions, provide superior hot tack strength, oil resistance, impact resistance at cold temperatures and excellent thermoformability properties. These are important features for resisting blast-throughs and ensuring blasting reliability in demanding environments, such as open pit mining in harsh environments. Superior hot tack strength, strain hardening, and excellent thermoformability properties of the ionomer materials ensure uniform powder distribution along the shock tube during construction and avoid undesired powder accumulation due to deformation or vibration during use. Oil or chemical resistance is another feature of Ionomers. This allows improved property retention in contact with oils and hence longer sleep times of the shock tube. Another feature of these highly engineered ionomers is superior impact strength at low temperatures. This plays an important role considering the resistance to fly rock impact in open pit mining operations in particular in cold climates.

Jan 1, 2011

By S. Mansfield, A. Sharma

At a large open cut copper mine, in pit crushing and conveying is used to shorten haul routes and minimise stockpiling of ore. This strategy decreases capital expenditure by reducing the number of haul trucks and excavators required and reduces the need to rehandle ore from stockpiles with a secondary load and haul fleet, with an overall goal of lowering operating costs and carbon emissions. As the mine has developed and expanded, it was necessary to extend the conveying network and install a fourth, semi-mobile crusher to increase the output of the operation, while maintaining the operational efficiencies. This required the blasting of a new tipping bench and pocket for the installation of one of the largest and most powerful semi-mobile, crushing plants. Fed by 360 tonne (396 ton) ultra-heavy class haul trucks, the KB 63-130 Pro gyratory crusher is the highest capacity available in the market. This paper describes the holistic process that was applied to model, design and execute the blasts required to create the pocket for the semi-mobile crusher, the surrounding tipping bench, plus the conveyor corridor and access ramp used by the ultra-heavy class trucks.

Jan 1, 2024

By Stuart Brashear, Lee Schettler

"The effect of water on several ANFO/emulsion blend ratios is documented by both physicalobservations and analytical testing to demonstrate the effect even small quantities of water canhave on water resistant blends."

Jan 1, 1996

By S C. Brashear, D A. Anderson, A P. Ritter, S R. Winzer, R Broughton

Results of quarry blasts can be quantified to show the effects of controlled variables. Two studies have been carried out: one to document the effect of delay on fragmentation and the other to show the effects of higher relief patterns and more accurate initiators. By using such techniques as highspeed photography and timing studies of mucking and crushing operations, subtle differences in blasting efficiency can be measured and quarry blasting can be optimized. Given the range of available and developing blasting technologies, quarry operators should resort to quantitative analyses of their blasting practices to get maximum productivity.

Jan 1, 1985

By Michael S. Wieland

The stress waves generated during delay blasting in underground or surface mines not only fracture the surrounding coal, rock, or other strata, but also impact delayed charges remaining in neighboring boreholes. This crossing wave interaction is a ubiquitous fundamental damage mechanism, ultimately responsible for numerous occurrences of misfires and flyrock. The hazards and waste from wave-induced malfunctions are Just the recognized tip of the iceberg. Undetected marginal performance of damaged delay detonators and desensitized charges poses a tremendous unresolved problem, resulting in the reduction of mining profits and the certain retention of unwanted risks.

Jan 1, 1988

By R J. Roach, D Roy

After months of discussion on ways and means to improve productivity in the shaft sinking process, it was decided to look at those areas where, historically, methods have been stagnant for many years. These categories included drilling, hole diameter, drill patterns, explosive types, explosive loads, initiation techniques, cut design, wall control, fragmentation and heated magazines.

Jan 1, 1997

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Simav Bargu, Savas Gorgun, Derya Kucukbrtem, Esat Tansev

Although many research studies had been carried out in the past in order to eliminate environmental issues produced from blasting unfortunately a general approach or formula has not been established yet because of the complexity of the matter. In addition to the wave and ground motion characteristics, the complexity of blasting parameters and site factors restrict the developing of a general criterion. So experimental site-specific studies should be still done in order to predict and control blasting effects.

Jan 1, 2002

By James Stuart

Explosive components are common in electric power distribution systems. Basically, we use explosives either to open or to close a circuit very quickly, in order to avoid electrical catastrophe. We use explosives in these important applications, because explosive materials are compact, inexpensive, long-lived, powerful, and can be triggered instantly. A lead-alloy fuse will melt when excessive electric current passes through it. A small fuse of this type melts quickly. However, a lead-alloy fuse for high current levels must be larger, and takes longer to melt. Thus, at high current levels, a lead-alloy fuse offers inadequate protection, because electrical catastrophe might happen, before the fuse melts. We need faster-acting, explosive components.

Jan 1, 2009

By P D. Katsabanis

The phenomenon of sympathetic detonations in blastholes is investigated by comparing experimental observations and numerical modelling results. Numerical modelling using the TDL computer code and Forest Fire decomposition rates for commercial explosives has shown the importance of blasthole diameter, impedance of stemming material and host rock. Comparison with experimental observations has also shown that sympathetic detonations cannot always be treated as shock to detonation transitions (SDT). Examination of previous results which have been obtained from calibrated low amplitude shock experiments reveal that there is an ignition threshold prior to the detonation threshold. The difference between the two thresholds is more pronounced in the case of air bubble sensitized products. The ignition threshold can be very important under the confinement provided by the blasthole and the conditions of application. It also correlates well with the pressures expected at the gap distances of interest in the practical application. It is suggested that critical energies are used as the criterion for cross initiation in blastholes. Practical suggestions based on the numerical calculations and experiments based on these calculations are also given and discussed.

Jan 1, 1992

By R. Sibley, K. Perry, E. McCorkle, M. Coy

Black powder has been used in fireworks since the 10 th century in China. To this day, black powder still has a variety of uses, including fireworks, and remains relatively unchanged. Black powder is used in the firework shell to help produce the effect and in the lift charge to propel the shell skyward. The performance of fireworks shells used in displays varies greatly. In fireworks shells, there are two different black powder charges that differ in construction based on the desired performance of the shell. The two charges consist of the lift charge and the break charge. The lift charge is the first to fire and propels the shell out of the mortar. The break charge is the second to fire and is initiated after a delay from the lift charge; its purpose is to burst the shells effect over the desired area of the sky. The lift charge provides the shell with its initial velocity by pressurizing the mortar below the shell body. The pressurization process is violent and occurs in fractions of a second. The purpose of these experiments are to better understand the pressures sustained in fireworks mortars during the firing process. Mortars and shells vary by size and weight. Pressures in each mortar were monitored at various heights along the mortar to provide a pressure profile during shell lift. A high-speed camera was used to measure shell exit velocity near the mortar’s muzzle. This information was correlated with the size and weight of shells and their respective lift charges

Jan 1, 2024

By Wawa Jaka Sungkawa, Slamet Rachman Jaka, Tom Dermody

A project was undertaken to research and develop a method to confidently predict vibration. It was decided that the scaled distance formulas were not adequate to predict vibration when using non-electric detonators, as accurate wave propagation could not be achieved. The problem is how to manage of complex geology condition related with wave propagation in ground vibration control. Geological condition mapping with specific spatial range can and combine with Signature Hole Analysis be a solution to make wave propagation easier to accommodate in ground vibration control

Feb 1, 2020