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Investigating blast vibrations typically utilises scaling and attenuation models for prediction of vibration amplitude over a range of charge weights and distances. A number of generalised relationships have been established from many years of far-field data analysis, where small changes in charge weight and ray-path distance are less critical. Under far-field conditions, small variations in local geology or geometry do not significantly affect the vibration scaling behaviour over an expected range of data. In the near to intermediate-field (less than 5 times the explosive charge length), small variations in wavepath and rock mass conditions between a blast and a monitoring point can greatly affect the outcome of vibration modelling. This case is especially true for underground blasting in sublevel open stoping, where the paths of blast-induced vibrations regularly encounter voids and preconditioned ground.

Jan 1, 2010

By Sérgio Augusto Ferreira, Alan Gerson Diaz Butron, Carlos E. Arroyo, Marcus Neves, Jorhs Enrique Casimiro Huayhua, Dieggo Santos, Eventomar Junior

The presence of natural underground cavities is normally a characteristic of iron ore deposits, specifically in tropical deposits. Brazil and the United States are the only countries that have a legislation to protect these structures, but in Brazil this legislation is very specific for the existing cavities in the federal territory. These cavities are classified by their level of relevance as high, medium, and low. From this perspective, its preservation becomes mandatory, especially, for those of high relevance in order to protect the species (flora and fauna) that live in them. When these structures are within the production phases, it becomes a challenge to exploit these reserves with the use of commercial explosives, since these structures condition and may restrict the use and amount of explosive charge. This paper presents the methodology of controlled blasting associated with predictability via realistic simulation in production polygons, applied in a Brazilian iron ore mine where there is a presence of high relevance natural cavities with restrictions in relation to the limits of Peak Particle Velocity (PPV), which is product of detonation.

Feb 6, 2023

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 Jorge Cárdenas, Diego Gamarra

In previous phases of the mine, a landslide resulted in several losses in production delays. The stability of slopes in a mining operation is critical for the sustainability of the operation, as they are exposed to vibrations and damage caused by blasting. Therefore, it is essential to implement controls and innovative technologies to reduce these vibrations levels. This study focuses on the application of low-energy emulsions with lower densities than conventional explosives, developed to reduce vibrations and the energy delivered to the rock mass adjacent to the near blast holes as a buffer row. Near field studies were carried out by embedding triaxial geophones. Vibrations were recorded, and mathematical models of vibration associated with different types of explosive mixtures were generated. This allowed us to determine the benefit of implementing low-density explosives in reducing vibrations compared to Heavy ANFO explosives. The application of low-energy explosives with densities ranging from 0.7 to 0.8 g/cm³ and Relative Bulk Strength (RBS) of 51-65 allows for a 40% reduction in vibrations compared to the detonation of Heavy ANFO explosives.

Jan 21, 2025

By U. Prasad

This paper summarizes the investigation carried out on a wide range of rock types, subjected to high velocity impact to simulate explosive action. A Split- Hopkinson Bar apparatus was used to generate the high velocity impact. The rock samples included both homogeneous and isotropic, and anisotropic types. The strain rate achieved was between 600 and 12OO/sec, The respective measured dynamic compressive strengths were compared with their low strain-rate or static values. It was found that the ratio of the dynamic to static values ranged between 2.5 and 4.6. It was also determined that the high strain-rate loading produced finer fragment size distribution than the static loading. The fragment size distribution from the two strain-rate regimes has been further analyzed to establish correlation with rock types and the strength characteristics. The results also confirm that high strain-rate loading (i.e. high detonation pressure and high velocity of detonation in an explosive column) would significantly affect the degree of fineness in a blast.

Jan 1, 2001

By Bruce R. Leland, Steven H. Smith, John D. Paulson

The USDA - Wildlife Services has been removing beaver dams with explosives for over 30 years. This paper will discuss the history of the explosives program, summarize how we've evolved, and highlight our work removing beaver dams in unique locations.

Feb 1, 2020

By Lon Santis, Michael Swisdak, David Leidel, John Tatom

The Institute of Makers of Explosives (IME) and A-P-T Research, Inc (APT) have developed and released a quantitative risk management tool, IMESAFR (IME Safety Analysis For Risk), for the commercial explosives industry. Consequence algorithms in IMESAFR are considered state-of-the-art. Generally, they mirror those in SAFER (US Department of Defense Explosives Safety Board quantitative risk management software). The science behind the software has now been assessed for its maturity. Results have identified areas where additional test consequence data could improve predictions. To address these areas, full-scale testing programs to provide the needed data have been formulated. Proposed testing efforts include work to: (1) improve characterization of explosive articles now absent from SAFER, and (2) refine modeling of the Potential Explosion Site (PES) types, particularly small metal structures, also not found in SAFER. Goals of each program as well as requirements for conducting the tests have been established. Testing results are to be used to improve the algorithms and to further the state-of-the-art in risk-based explosives safety.

Jan 1, 2012

By Alexander Hauck, Dimitri Jung, Uli Leiste

This paper describes results from small scale tests conducted to determine the distribution of impulse on target plates when subjected to loading due to the detonation of a buried mine. The tests were conducted with saturated sand, dry sand, and water as the loading media. Tests were conducted for flat plates and for plates with angled bottoms. Previous testing has shown that angled bottoms can reduce the total vertical impulse delivered to the vehicle significantly. Different stand off distances were investigated as well as loading of the targets both on center and off center. It is very important to know not only the total impulse delivered by a detonating charge but also how this impulse is distributed over the bottom of the vehicle. A complete understanding of specific impulse will permit those parts of the vehicle, taking the greatest amount of loading, to be sized properly. Experimental results were compared to analytical expressions provided by Westine and Tremblay.

Jan 1, 2010

By Uli Leiste

Two papers are presented which examine Air Deck Blasting, one from a computational aspect and the other from a shock aspect.

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 L C. Taylor

Both the U. S. Navy and the U. S. Army are interested in knowing more about the loading applied to vehicles which are unfortunate enough to encounter a detonation of a buried mine in the course of performing their normal duties. The Dynamic Effects Laboratory at the University of Maryland has been involved in small scale testing for ten years to assist the Navy and the Army in understanding the loads that are applied to personnel carriers when a buried explosive detonates beneath them. This paper describes results from small scale tests conducted to determine the loading mechanisms on target plates when subjected to loading due to the detonation of a buried mine in saturated sand, dry sand, and water. Transparent target plates were utilized in order to determine the loading process beneath a floor board on armored vehicles. Various charge sizes were scaled in the laboratory accordingly to a standardized full size threat encountered in the battlefield. Tests were conducted in saturated sand, dry sand, and water keeping the stand-off distance of the target and the depth of burial of the charge constant. In the case of water impacting a transparent PMMA plate the crack propagation was recorded and the crack velocity is determined. Additional tests were performed in saturated sand by varying the stand-off distance of the target but keeping the depth of burial of the charge constant. The small-scale test results could be scaled to full scale by using verified scaling laws.

Jan 1, 2016

By Lon Santis

This paper analyzes 110 serious accidents that occurred during the use of commercial explosives in mining, construction, and other industries since 1992. Data from the Mine Safety and Health Administration (MSHA), the Institute of Makers of Explosives (IME) members’ reports, and media reports were used. Only accidents that resulted in a fatality, significant lost work time, or injury to the public were considered in this analysis. The accident data were analyzed for trends in frequency, type of industry, cause, type of individual harmed, and geographical region. Although the data showed that explosives accidents are decreasing in frequency, still, 29 people were killed and 134 injured. Eightyfive of the accidents occurred in mining, 17 occurred in construction, and 8 occurred in other industries including oil recovery, seismic exploration, agriculture, logging, boiler cleaning, and avalanche blasting. As other studies have shown, flyrock and failure of blast area security caused over half of the accidents. Mishandling, misfires, or fumes caused just over one-third of the accidents. Lightning and drilling into explosives were responsible for the remainder of accidents.

Jan 1, 2003

By Frank Sames, Brad Terhune

In many construction projects and in most quarrying operations drilling and blasting remains the only feasible method of loosening rock in the removal of rock or overburden, the development of the quarry and in the production process of crushed stone. Often, a blasting plan is required for the project or the quarry’s permit with primary concerns over safety and site security, and compliance with environmental regulations or standards. From this plan, a blasting program has to be developed considering the varying requirements of production, the advance of the mineral extraction and the environmental impact. The actual blast design requires a planning and optimization process. This optimization process is driven by the blasting technicians/engineers, project or mine management and often by community concerns. The blast design process comprises the selection of blast parameters, including the explosives, and the actual layout of the blast. Design tools and controls range from conventional methods based on established blasting practices to advanced design tools or computer models. Blast monitoring and evaluation can also range from empirical to advanced blast assessment. The data and information from each blast or a series of blasts can further be used in the optimization process. Its success depends upon recording the data, the timely transformation of the data to relevant information, and the development of process oriented knowledge. The elements of the blast design process are summarized and described with examples of state-of-the art engineering controls. The reporting and monitoring of individual blasts is discussed with respect to data management and information systems. A conceptual overview of the components and interfaces of a blasting program is given and discussed on the background of technical, management and community concerns.

Jan 1, 2004

By Calvin Konya, Anthony Konya

Presplitting is a form of blasting that when executed properly will create a smooth wall that will minimize secondary conditioning. In recent years, presplitting has become a popular technique to be used in both the mining and construction industries, however, presplitting fails on many occasions because of ‘geologic conditions’. This is typically because of improper explosive loads consisting of overloading and underloading blastholes. In this paper the authors introduce new factors such as a presplit factor which varies for different rock types, selection criteria for the spacing of presplits, and the optimization of explosive load for the technique of Precision Presplitting.

Jan 1, 2017

By Larry Schneider

In 1998, the Blast Vibration and Seismograph Section of the International Society of Explosives Engineers formed a working group to collect and compile a list of regulations limiting ground vibrations from blasting. The goal was to locate those countries, states, provinces, and cities that have such regulations, identify which governmental body enforces them, and determine what limits on ground vibrations are imposed upon the blasting operations. In the course of this study, data was collected from over 60 jurisdictions where peak particle velocity restrictions range from non-existent to very stringent. Some of the regulations were found to be based upon standards grounded in good science, while others possess little or no technical justification. This presentation will summarize the findings of the subcommittee, focusing primarily on what the limits are, which type of blasting operations must adhere to them, and to what structures they apply. The degree to which these regulations are based upon valid scientific and engineering research will be discussed. A listing of specific locations having such regulations and information about those regulations will be provide

Jan 1, 2000

By Ron Stewart, Richard Youmaran, Andy Adler

In the current context of heightened concerns with explosives security, there is significant interest in technological controls to improve security. It is important to be able to control what is fired, by whom, where and when. This paper describes research Orica has performed to investigate and test biometric systems to address the question of "by whom". The goal of this research is to incorporate the most suitable biometric system onto the 'blaster' unit of an electronic initiation system. This approach will ensure that only authorized personnel can initiate a blast involving electronic detonators. Requirements analysis: we initially explored many different biometric technologies to evaluate them against the requirements, including security, usability, ruggedness, size, form factor, privacy, and operational temperature range, This analysis identified chip based fingerprint sensors as the best candidate. Development of prototype units: in order to test the identified sensors, we modified standard, commercially-available, electronic blast initiation units ("blaster") to incorporate a fingerprint reader. Testing and evaluation: Biometric We conducted a biometric scenario evaluation in order to determine: 1) security level (measured by false accept rate (FAR)); 2) usability (measured by failure to enroll (FTE) and false reject rates (FRR)), and to 3) discover environment specific issues and challenges (such as temperature, humidity, dirt, or those related to the usage patterns of the user group). Tests were conducted at quarry sites in eastern Ontario, Canada. Results show rates of: FAR= 0%, FTE= 1.67%, FRR= 28.81%. Overall, these results suggest that this fingerprint biometric technology has a good level of usability in this application of electronic blast initiation control.

Jan 1, 2007

By S C. Alford

Explosive fracturing of metal is usually considered to be an imprecise process but, by careful consideration of shock-wave geometry, precise results are obtainable. The limited development of such charges is attributed to experimental difficulties. A charge configuration has now been devised in which a prismatic wave-shaping element is used to resolve the shock-waves entering a target plate into two convergent components. The extreme pressure caused by their collision initiates a diamond fracture in the proximal target face, and coincidence of reflected tension waves generates a fracture in the distal face. A combination of these effects breaks the target. An embodiment of S.R.T. is described which is flexible, magnetic and contains no cavities.

Jan 1, 1986

By Panagiotis (Takis) Katsabanis, Lyall Workman, Jack Eloranta

The reduction of metallic ores to concentrate consumes a great deal of electrical energy. In the past two decades, a number of case studies have demonstrated a beneficial relationship between powder factor and grindability. However, changes in mill performance cannot be attributed to changes in feed size alone. Blasting energy and the distribution of that energy appears to affect subsequent comminution beyond crushing. This experience has prompted researchers to attempt to duplicate and quantify the mechanisms involved. To date, published reports indicate a measure of success. However, the blast engineer and the mill engineer still lack the tools and basic understanding necessary for full drill to mill optimization.

Jan 1, 2015

By Dennis Wilzbacher, John Wiegand

In an effort to reduce the cost of bulk explosives, Vigo Coal Company found that the addition of coal mined at their Friendsville Mine, not only reduced explosive costs, but also appeared to actually enhance blasting performance. The Friendsville Coal lies at the base of the Mattoon geologic formation within the Mcleansboro Group of the Missourian Series of the Pennsylvanian Geologic System in Southern Illinois. Vigo Coal Company commissioned VIBRONICS, INC., an independent blasting consulting company to quantify actual blasting performance. Insitu sonic velocity testing of overburden was conducted to determine the P-wave velocity of the sandstone present at Vigo’s Cypress Creek Mine, where the initial testing was conducted. Numerous VOD (velocity of detonation) recordings were obtained for varying blends of ANFO/Coal (now named Carbo*Prill). Cast blast percentages were determined for both Carbo*Prill and non coal blended bulk explosive blasts. The VOD of the coal blended product was intentionally reduced so as to more closely match the P-wave velocity of the sandstone overburden. Explosive blends containing as much as 40-50 percent coal were tested. Explosive blends containing greater than 30 percent coal, have been used in Cypress Creek Mine overburden production blasts. The coal blends appear to produce better fragmentation and yield excellent cast blast performance. Safer mining conditions were also observed. Flyrock potential was reduced. The blasts produced less back break, producing a safer highwall. Stripping dozer and shovel production rose during the testing period and equipment repair costs were lowered due to an increase in overburden fragmentation. Blasting vibrations were reduced, in part due to the lowered detonation velocity of the ANFO/Coal mixture. The Friendsville Coal Seam appears to contain inherent chemical and physical properties that enhance blasting performance. The use of Carbo*Prill has been approved by MSHA, BATF, the State of Illinois, and the State of Indiana. This paper will provide details concerning testing procedures, blast performance analysis, recommendations and conclusions for using this alternative blasting mixture.

Jan 1, 2007

By Adrian J. Moore, Alan B. Richards, Rob Evans

Air and ground vibration from blasting is influenced by the delay pattern that is used. Wavefronts from blastholes fired in a blasting pattern can combine in certain circumstances to give increased blast vibration levels. A simple computer model has been developed which shows the combined effect of wavefronts from a multi-hole blast and identifies if wavefront reinforcement occurs, and permits delay patterns to be designed which will avoid or reduce wavefront reinforcement.

Jan 1, 1994