Search Documents

By Frank Lucca

This study is based on a six month study performed for Lee County, Florida. The study was based on blasting for land development and how this type of blasting affects structures. The study is investigates peak particle velocities and the relationship to other environmental and manmade forces that affect structures. The study also explores the effect of geology on blast vibration. After completion in Lee County, the study was then continued in the quarry environment in Vermont and extremely tight blasting environment of New York City. Charge diameters were 127mm (5 inches) or less.

Jan 1, 2006

By Nadir Plasencia, Rogerio: Neves Mota

The evaluation of vibrations induced to build structures is one of the main concerns when dealing with blast works. EDP, the main Portuguese producer of electricity is presently incrementing energy production in some old hydropower dams by installing new production plants. The need for not disrupting production during the upgrading works causes some concerns related with vibrations induced to the production engines. Vibration estimation was performed in two of these dams, constructed in a granite environment, by performing controlled blasts. For each dam site, some vibration transmissivity laws were developed with the fitting process.

Jan 1, 2008

By Alastair Torrance, George Boucher, Roger Keller

An investigative blast programme has been carried out to provide information on the best blasting methods to excavate Chek Lap Kok island in Hong Kong for the new airport. The objectives of the programme included the assessment of a range of blast design parameters and their influence on fragmentation. This has been evaluated by physical assessment, photo digitising of the muckpile and computer predictions. In addition, a model to predict the three dimensional muckpile shape has been successfully calibrated.

Jan 1, 1992

By P Albert

A wedge-shaped underwater rock plug has to be blasted in order to tap the reservoir and furnish water to a new underground powerhouse at Manicouagan-5. The paper deals with the design and engineering aspects of drilling and blasting of this plug where the topographical configuration is extremely difficult. In this study small diameter vertical holes are considered with the OD-method and a fixed platform is recommended for drilling and loading operations.

Jan 1, 1984

By James L. Wilcox, Douglass P. Bacon

As the U.S. Environmental Protection Agency (USEPA) and state regulators increase the stringency and enforcement of regulations concerning emissions produced by open-air detonation of energetic materials, research must provide the means of obtaining emissions data. The BangBox emissions testing program established the technical foundations for emissions characterization which have been accepted by the USEPA and other regulatory agencies; the technical issues remaining are nettlesome and require new approaches in test procedures.

Jan 1, 1996

By Jim Breedlove, Stephen P. Case

When a major ground subsidence occurred in the AKZO Salt mine at Retsof New York, the company was forced to pick up their production from a lower mine level. Before full production on the lower level was possible, an escapeway and ventilation shaft would have to be constructed. Construction of a shaft under emergency conditions required some special techniques. Dynatec Mine Construction, Inc. of Lakewood Colorado was awarded a contract for the project.

Jan 1, 1995

By He Guangyi

During rock blasting in extending deep cutting from Jiu Li Mountain to Dong Zhuang Village in Jiao Zhi Railway line, we have drilled deep hole with large scale diving drilling machine and successfully carried on controlled blasting. This has provided new experiences for rock blasting in extending existing cutting. The aim of this article is to provide an introduction to bench height, blast holes arrangement, powder charge calculation, and detonating technique during blasting.

Jan 1, 1997

By Thomas Bakley, Rob Lee, Jay Rodgers

The present state of technology in Controlled Blasting uses standard explosives’ products to create a crack between holes along a desired line of break. The resulting pre-split, post-shear or cut line is often of variable quality with unwanted damage at right angles to the desired cut line. A new concept in Detonating Cord manufacturing has provided a radically different performing explosive. This new Cord has reduced the Velocity of Detonation by more than a third. It changes the Detonation Pressure proMe of Detonating Cord to a lower and longer sustained pressure pulse. In addition, it develops more gas than conventional cords. At the same time it maintains all of the handling and reliability advantages of conventional Detonating Cord.

Jan 1, 2001

By R Vuolio, B A. Jonsson

In the center of Helsinki - capital of Finland - extensive blasting operations were carried out during the years 1982 - 84. At the corner of the streets Mannerheimintie and Simonkatu - in the Forum block - about 125,000 cu.m. of rock were blasted to give place for a new modern shopping centre (Fig. 1). Added to this amount of rock another 10,000 cu.m. were blasted for a transport tunnel to an adjacent underground bombshelter (Fig.2) which is to be used as a parking place in peace-time. The blasting work was demanding and difficult to carry out due to old buildings surrounding the work-site as well as computers and other sensitive equipment installed in some of them.

Jan 1, 1985

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 Ingvar Hansson, Bjorn A. Jonsson, Bernt Larsson

In the Kiruna Research Mine, Sweden, four large open stopes have been mined, leaving intermediate piIlars and crown pillars. At the final stage of mining mass blasting of the crown pillars above two of the stopes was carried out. The crown pillars contained some 290,000 tons of iron ore. In the mass blast a new initiation technique was used, utilizing the new non-electric system NONEL ? UNIDET. The blasting technique including vibration control is described. The mass blast resulted in high recovery, good fragmentation and low vibration levels.

Jan 1, 1986

By Phillip R. Mulligan, Catherine Johnson, Edward Kinzel, Cody Lough, Jason Ho

A shaped charge is an explosive device used to focus detonation energy in a desired direction. Shaped charges have numerous applications in several industries such as oil extraction, weaponry and demolition. The focusing of the detonation energy is the result of the Munroe Effect, which greatly increases the penetration properties of the explosive due to a void in the explosive’s volume. The void in the explosive is lined with a metal substrate that becomes a super-heated projectile when the explosive is detonated. Additive Manufacturing (AM) can allow greater design freedom and geometric complexity for the liner portion of the shaped charge. Specifically, hierarchical structuring and functional grading can potentially provide greater velocity, directionality, and efficiency. By utilizing AM, the conventional use of shaped charges can be greatly expanded upon and may open new possibilities. In this work, selective laser melting (SLM) was used to explore different conical shaped charge (CSC) liners made out of stainless steel 304L. A series of liners were tested that had varying densities and were compared to conventional liners. The CSCs were filled with the high explosive Composition C-4 and detonated to evaluate performance. The blast events were recorded using break wire screens to calculate the velocity of the jet through steel target plates over a standoff of 6 times the charge diameter. A high-speed camera recorded the blast event to calculate the velocity of the jet through the air. The depth of penetration into the steel target plates was also used as a measurement of the effectiveness of the CSCs. The aim of this work is to show the potential for advanced shaped charges produced using SLM.

Jan 1, 2019

By Ashley Haslett

A European Directive on Identification & Traceability of explosives came into effect on the 4th of April 2008. This directive is intended to establish a harmonised system for the unique identification and traceability of all packaged explosives, detonators, reels of detonating cord and primers used in civil applications across the European Union. The directive must be adopted into the national legislation of each European Union member state by the 5th of April 2009 with compliance achieved throughout Europe by the 5th of April 2012. The requirements of the Directive apply to all explosives manufactured, used and imported into the European Union from 5th April 2012.

Jan 1, 2010

By Joel Warneke, Cristian Caceres, Ed Mchugh

NIOSH researchers collected basic data from two blast rounds at the SSX-Steer Mine as a component of a larger study on controlled blasting, the goal of which is to reduce injuries from falling rocks in underground mines. Drilling and blasting procedures at the mine were observed. Rock mass property data were collected, a program of seismic monitoring and analysis was conducted, and 3-D laser survey scans of the workings before and after each blast were performed. The geologic data showed that the rock mass quality was characterized as poor to very poor. It was essentially uniform within the panels examined. The recorded seismic data indicated that fill material acted as an effective damper to seismic energy. The pre- and post-blast laser scans showed both over-break and under-break conditions, highlighting the problems associated with blasting a weak rock mass. By comparing the achieved results to the intended design, potential improvements in the drilling and blasting practices can be identified. Comparison of these data with similar data from other mines will help define how various combinations of rock and fill behave during blasting. Through studies such as these, data collection procedures and analysis techniques can be refined. An ultimate goal is to develop blast procedures tied to rock mass characteristics that can minimize damage to rock in the perimeter of the opening, limiting the amount of loose rock and improving the safety of miners.

Jan 1, 2008

By Maria Sullivan

There have been many papers and articles presented over the last 60 years questioning the relevance of the 8-millisecond blasting delay window as an ‘Industry rule of thumb’. The concept of using delays between blast holes to minimise vibration is well understood and agreed upon. The means for evaluating what that minimum delay interval needs to be, for a particular site given their ground conditions, design parameters and blasting techniques, is much less established. Some sites haven’t even recognised their required minimum delay value may not be 8-milliseconds!

Feb 6, 2023

By Lon Santis, David Leidel, John Tatom, Meredith Hardwick

This paper describes the development and methodology of the Institute of Makers of Explosives’ Safety Analysis for Risk (IMESAFR), a risk analysis software program for commercial explosives operations. IME is a nonprofit safety and security association devoted to the safe and secure manufacture, transportation, storage, and use or disposal of commercial explosives in the US and Canada since 1913. The software methodology’s basis is the U.S. Department of Defense Risk Based Explosives Safety Criteria Team’s Safety Assessment for Explosives Risk (SAFER) software. A diverse group of industry and government experts contributed to modifications to SAFER that reflect commercial operations. IMESAFR is intended to supplement the American Table of Distances (ATD) and offer standardized methods of managing risk from a wide variety of commercial explosives operations where the ATD does not apply. The modifications made to SAFER primarily involved the addition of commercial activities and potential explosives sites (PES). A review of commercial explosives accidents and operations over the last 20 years served as the basis for establishing probability of event values. An industry survey of commercial PES types in the U.S. and Canada was conducted to identify and address critical differences in commercial structures as compared to the military structures in SAFER. The paper concludes with discussion of the potential uses for quantitative risk analysis (QRA) and a description of other explosion effects software

Jan 1, 2007

By A. Torrance

A better understanding of the detonation performance of an explosive charge can be gained by directly measuring pressure, temperature and velocity of detonation (VOD). This is particularly important with commercial explosives because their performance is directly influenced by the degree of confinement given by the borehole diameter and the surrounding rock mass. A project funded by the Australian Coal Association Research Program (ACARP) was initiated in early 2009 with the view to design and build cost effective prototype instrumentation to measure the relative differences in detonation pressures and temperatures of commercial mining explosives. The project’s primary focus was on low density explosives. Low density (also referred to as low shock) explosives have been available in various forms for nearly 20 years. Identifying the pressure release patterns of both conventional and low density explosives under different geotechnical conditions should provide the necessary information to both validate detonation codes and better define input parameters for breakage and fragmentation models. This paper gives a general description of the prototype instrumentation developed and reports on the results obtained to date in testing the proposed instrumentation in laboratory scale conditions.

Jan 1, 2011

By Paul Worsey, Larry Kenchel, David Randall, Mark Schmidt

The University of Missouri-Rolla (UMR) has historically maintained a manual, paper inventory of explosives stored and used at the university. Although this system was accurate for inventory control and reporting criteria, it was labor intense and delays in record keeping were predominant. A directive from the university’s administration mandated the development of a precise real time system “on-line” to maintain and control the explosives inventory in line with the universities new chemical tracking policies.

Jan 1, 2001

By Alejandro Ferrada Vergara, María Jesús Barros Godoy

The need for a basic method for selecting explosives based on rock mass or intact rock properties for mining and construction arises from the limited consideration given to these factors when choosing among products and also an implicit overestimation of the explosive power to fragment the rock. This study highlights the importance of evaluating different properties such as rock strength, deformation, fracturing, detonation velocity and energy release when selecting explosives. The concept of characteristic impedance, which considers rock strength against shock waves generated by explosive detonation, is introduced. Understanding this concept is crucial for assessing explosive behavior according to various rock types. The study concludes with a practical guide table that categorizes rock properties and provides recommendations for selecting explosives based on rock mass and rock properties. However, it is important to consider other relevant factors, such as the presence of water or nearby instabilities, which can influence the final choice of explosives.

Jan 21, 2025

By O E. Jr Crenwelge

Recently promulgated regulations governing blast induced ground vibrations in the mining industry contain a frequency criterion as one option for verifying compliance. This criterion is based upon an oversimplified method which assigns the entire peak particle velocity amplitude to one frequency. Depending upon the nature of the vibration time history, it is possible that this frequency may not even be one of the predominant frequencies of the signal. In addition, the criterion does not specifically define the data analysis approach to be used by the industry for obtaining either the amplitudes or the frequencies of the vibration components. And because personnel in this industry generally have little understanding of vibration phenomena, a number of different approaches are currently being used for satisfying the criterion. This paper presents a method for obtaining both the Fourier amplitude-frequency spectrum and the integrated predominant amplitude-frequency components for the vibration record. The method is both physically and mathematically correct and is in common use in a number of other industries. Therefore, it should be of help to regulators, blasters, and consultants charged with developing, enforcing, or implementing ground vibration criteria.

Jan 1, 1988