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By Catharine L. VanOmmeren

Emulsion quality characteristics such as shelf life, handling, and sensitivity are critical to the end-user. It is therefore important that the consumer be prepared to ask his supplier specific questions. To do so, he needs to have a basic understanding of what an emulsion is and how emulsion properties can affect safety, performance, and environmental impact. The criteria to be covered include: energy, velocity, sensitivity, minimum priming, shelf life, pumpability, effect of AN quality, over-the-road handling, and formulation The consumer will learn how each of these properties can directly affect him. The information will enable him to set minimum standards in product selection, blending, and application.

Jan 1, 1989

By P D. Katsabanis, S Kim

A number of small scale fragmentation tests have been conducted to analyze the effects of blasting effort on the grindability of granite, granodiorite, limestone and iron ore. Powder factors were modified, post-blast fragments were screened and drop weight tests were conducted on fragments of different sizes to deliver a variety of specific impact energies. The fragmentation from the drop weight tests has been analyzed to examine the effect of impact energy and powder factor on size reduction. A consistent effect of blasting on the various fractions of the fragmentation distribution has been obtained for all rocks used. The effect of powder factor on the impact fracturing of the rocks has been expressed in a convenient relationship between progeny size, impact energy and powder factor used in obtaining the primary fragmentation. It is clear that explosives consumption affects downstream size reduction; depending on the rock, the effect can be substantial at coarser final sizes but very small in the case of grinding to small final sizes. Differences from the expected trend can be attributed to changes in blast design. As an example, the effect of in-hole collision of detonation waves is analyzed.

Jan 1, 2011

By R. Ranjan

Stanstead granite has been investigated with respect to its dynamic compressive strength and its strain-rate dependency. A standard Split-Hopkinson Pressure Bar (SHPB) apparatus has been employed to generate strain rates of up to ~500/s through high-velocity impact. The diameters of the test samples were 19 mm, and tested under impact velocities up to ~20m/s. It is found that even within this limited range of strain rates, the dynamic compressive strength for the granite showed nearly a 100% increase in value compared to those obtained under static loading conditions (e.g. compressive strength of 394 MPa at a strain-rate of 600/s, compared to 215 MPa obtained under static loading). The details of the test are described in terms of incident, reflected and transmitted stress pulses, along with means to achieve stress equilibrium in the test samples under dynamic loading conditions. The advantage and drawback of the use of ‘pulse shaping’ techniques to achieve dynamic stress equilibrium are also detailed.

Jan 1, 2010

By Nikolaos Petropoulos, Ulf Nyberg, Ulf Stenman, Daniel Johansson, Håkan Schunnesson

The optimization of the explosive performance is of great importance since blasting is extensively used in civil projects and mining industry. An improved understanding of how the energy from the detonation of an explosive is transmitted to the surrounding rock mass is critical information for the proper selection of an explosive. Therefore, an extensive study was done on the influence of the blasthole diameter on the Velocity of Detonation (VoD) and the detonation front curvature.

Feb 1, 2020

By Neal Lee, Braden Lusk, John Silva Castro

One of the most common assumptions regarding the use of ANFO versus utilizing 100% sensitized emulsion is that ANFO “turns over” the muck-pile better, due to the “higher gas volume” supposedly inherent in ANFO. This paper examines this assumption and provides quantitative data for analysis. Total gas volume from each product was evaluated using Orica’s I.D.E.X. Code analysis. This analysis was used to determine if gas volume is a significant contributor to differences in fragmentation and movement between blasts utilizing the two different products. A constant drilling and blasting cost per yard for given cut depth, hole diameter, stemming height and rock type was utilized. The cost per yard was held constant by adjusting patterns considering product, accessory, and drilling costs. Photographic fragmentation analysis, dig rates measured quantitatively through production tracking and time studies and qualitative information about the diggability of the blast provided through video recordings were used to evaluate performance. The data collected during the study is presented and recommendations are made regarding the performance of ANFO and Emulsion holding other variables constant for a limited number of blasts.

Jan 1, 2012

By Timothy Smith, Matthew Ryan, Dr. Anthony Konya

Hybrid specifications are a relatively new style of specifications specifically for the drilling and blasting industry that has seen widespread use over the last decade with the U.S. Army Corp of Engineers. This paper analyzed how this methodology was applied to develop this specification for the Soo Lock Deepening Project.

Feb 1, 2020

By Peter Duniam, Vivian Patz

History of the ExEx 1000 CAB system. l What we’ve learned using electronic timing. l Requirements for a second generation. EDD system. l The ExEx 2000 system - simple, versatile and cost effective

Jan 1, 1997

By Andrew F. McKown, Robert A. McClure

This paper will describe a trench blasting case history in close proximity to several adjacent structures, including a bridge abutment, railroad tracks, and utility pipes. Some design considerations involved in close-in blasting will be discussed, including allowable peak particle velocities and prevention of rock block movement. The importance of several trench blast round design factors is pointed out, including choice of explo sive to prevent propagation, maintaining a sufficiently high powder factor, and mucking out for maximum relief after every round. Vibration monitoring and good record keeping are shown to be important in order to evaluate blast problems and make modifications to round designs.

Jan 1, 1988

By Lon D. Santis

This paper describes a lightning warning system (LWS) in operation at the U.S. Bureau of Mines' (USBM) Pittsburgh Research Center (PRC) from December, 1989 to April, 1991. An electric field mill measured the DC atmospheric electrostatic field. Also, an economical on-line weather data service provided lightning location maps and other weather information. A system such as this can significantly improve the safety of explosive handling. The use of these two methods addresses the detection of thunderclouds building overhead and the prediction and tracking of developed storms. Warning reliability of the system was very good when data from both sources were considered. Experience showed, however, that use of either system alone would not provide adequate reliability in most situations. Some problems occurred with the field mill and there is some question whether the instrument is compatible with harsh mining environments or could be made portable. Another method ' of measuring electric field based on fiber optics is discussed. This technology may be able to overcome the problems with field mills.

Jan 1, 1993

By Joseph A. Meyers, Michael D. Stokes

This paper will focus on the use of Deflagrating Cartridges for tunnel excavation in Midtown Manhattan at Grand Central and 42nd Street Station, where the excavation has challenges due to the proximity of existing underground infrastructure and a contract blasting restriction. Skanska and FDNY’s collaborative teamwork successfully used deflagrating cartridges and gathered vibration data to properly predict ground vibrations on nearby infrastructure. In cities like Manhattan, conventional blasting excavation methods can be constrained or restricted entirely by the risk of damage to nearby structures, utilities, and disruption to everyday life on the streets. The introduction of Deflagrating Cartridges to the project offered a promising solution to mechanical excavation being used by providing controlled, precise, and deflagrating rock breaking capabilities that minimized disturbance to the above items. This technology minimizes the risk of vibration damage to preexisting infrastructure due to its reduced velocity of deflagration, making it useful for the location of our project. The team's approach involved numerous test shots to help determine the appropriate loading and timing sequence, as well as to collect data to properly be able to predict vibration on the adjacent structures. The successful application of deflagrating cartridges in the Grand Central area demonstrates their usefulness in logistically challenging underground excavation projects in urban cities. Through careful coordination and innovative use of this technology, the team was able to navigate the complexities of working near existing infrastructure while maintaining high levels of safety and productivity. Overall, our paper will speak to the importance of new technologies like deflagrating cartridges for usage in urban environments while minimizing disruption to the world above and below, the technology of these products, and the outcomes of our vibration data collection. By embracing these advancements, construction teams, owners, and other agencies can effectively address the unique challenges posed by projects in densely populated areas, while maintaining safety and productivity.

Jan 21, 2025

By Hideaki Kitajima, Daisuke Fukuda, Kazuma Moriya, Katsuya Sasaki, Katsuhiko Kaneko

The purpose of this research is to analyze the fracture process and achieve design optimization of a splitting method for concrete and rocks termed the electric discharge impulse crushing method (EDICM). The EDICM utilizes the cartridges being set in boreholes in the splitting target. The cartridge has a thin metal wire and is filled with nitromethane. By applying the electric discharge to the wire in the cartridge, plasma is caused leading to the vaporization of the wire. Then the deflagration of the nitromethane commences, which generates borehole pressure for splitting the target. Although the required splitting time is roughly several hundred micro-seconds and much slower than ordinary blasting, the fracturing still completes in quite short time and understanding the fracture process of opaque and brittle materials such as rock and concrete in this time scale is of academic importance.

Jan 1, 2011

By Nathan Rouse

This blast mitigation study examined the effects of a barrier wall on explosively driven pressures. This area of blast mitigation is of interest due to the many different applications involved in protecting a target from an explosive attack.

Jan 1, 2012

By Thomas Rupp, Michael Siegwart

The paper presents the vibration and sound emission measurement campaigns carried out in 2007 in preparation for the Ceneri-Basistunnel construction. We also present the vibration measurement campaign conducted during the construction of the Zimmerberg-Basistunnel. Both tunnels form an integral part of the Swiss Federal Railway Company Neue Eisenbahn Alpentransversale project (NEAT). This strategic project comprised the construction of several new tunnels. Its aim is the improvement of the existing infrastructure. The improved infrastructure will be able to accommodate a larger volume of railway traffic that is also crossing the Alps at higher speeds. The construction of the Ceneri-Basistunnel commenced in 2006. Both the Zimmerberg-Basistunnel and the Ceneri- Basistunnel are located underneath densely populated areas. Therefore, noise and vibration emissions have to be kept to a minimum and must not exceed applicable codes of practice. In order to identify the most appropriate blasting strategy for the yet to be constructed Ceneri-Basistunnel, blasting trials were conducted. The paper presents the findings of these trials and identifies ways to reduce both noise and vibration emissions from blasting. The construction of the first phase of the Zimmerberg-Basistunnel took place between 1999 and 2003. While the first phase is already in operation, the construction of the second phase has been postponed (commencement originally due in 2007). The Zimmerberg-Basistunnel connects the outskirts of Zürich with the city centre. As the tunnel site was not located close to the surface near populated grounds, no special measures were needed to reduce the noise emissions from blasting. However during the construction of the tunnel, the vibration emissions from blasting were monitored on more than 50 locations on the surface. The paper presents the analysis of some of the data. An emphasis is placed on the appropriate synopsis and presentation of data for documentation purposes.

Jan 1, 2009

By David Nemir, Jan Beck

A challenge in materials science is the production of a bulk solid material from a powder precursor. One solution is to use shockwave consolidation whereby a ductile tube is loaded with the powder of interest and then surrounded by an explosive. A detonator at the top of the explosive column initiates a symmetrical high-pressure pulse that moves inward and down the tube, causing the tube to deform and the interior powders to consolidate into a dense, well bonded bulk material.

Jan 1, 2016

By Italo Onederra, Miguel Araos

"In order to characterize non-ideal explosives, the explosives industry rely on unconfined velocity ofdetonation tests and where possible underwater pond tests. The information obtained from such tests isquite helpful, however it cannot tell us much about the dynamics of the detonation reaction process. The detonation process has been studied for ideal explosives and the reaction zone length have been measured. However, for non-ideal explosives, that type of information is not available. Therefore, the primary aim of this work was to capture the detonation process of a non-ideal explosive using high speed video camera to determine the zone length."

Jan 1, 2017

By Braden Lusk

Vibrations as a result of blasting practices in mining engineering are a complex phenomenon controlled by many variables. Mine blast vibration modeling and prediction is becoming more important as a consequence of the general negative perception of mining activity by the public. Many communities (all over the world) close to mining activity often complain about airblast and vibrations produced from blasting activity. It is important for the mining industry to have tools and understandable methodologies to model and predict blast vibration. These tools can then be used to control vibration at neighboring structures.

Jan 1, 2013

By Muhammad Yamani, Marsell Riviera, Herry Saputra, Rizky Amin

Drill and Blast processes in hot and reactive ground conditions are a severe challenge in mining, especially in the blasting process. Our main objective is safety issues without compromising the blasting outcome. Safety concerns include unexpected detonation, product damage, and misfire. However, apart from the issue of blasting safety, it is also crucial to maintain good results such as fragmentation, loader productivity, and ore dilution control. Therefore, we use a different product selection method to produce a safe and efficient blast. Pit Araren is one of the pits of the Tokatindung Gold Mine Project in North Sulawesi Province, Indonesia, classified as hot and reactive ground conditions that range from elevation of 25mRL temperature could reach to 98⁰C (208,4⁰F) based on actual measurement. The previous practice for blast holes with temperatures above 70⁰C (158⁰F) loaded with the primer that was specifically designed for hot and reactive ground conditions consisting of detonating cord and packages emulsion that specifically formulated to inhibit exothermic reaction then tied in with a combination of non-electric surface delay detonator and detonating cord initiator (short length non-electric surface delay detonator housed in plastic connector).

Feb 6, 2023

By C W. "Mickey" Bradley

Thunder strikes terror in the hearts of man and has since the advent of time. We all fear the unknown; even the Greeks created a god, THOR, to be responsible for the thunder and rain. Thunder, by itself, can't hurt anyone; it is simply hot air moving very fast. Thunder, however, is caused by lightning and lightning is what we need to fear and rightfully so. Annually, lightning kills hundreds of Americans, injures another 2,000, damages or destroys approximately 30,000 structures, 1 starts thousands of forest fires and strikes mine properties over 100,000 times.

Jan 1, 1992

By Robert Hopler

SECTION 9.---BORING AND BLASTING.*155. Blasting is the operation of bringing down and detaching from its bed or position masses of material by means of explosives.

Jan 1, 2011

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