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By Robert Hopler

A detonator is a copper tube about a quarter of an inch in diameter and an inch and a half long, closed at one end and containing in the closed end a small charge of fulminate of mercury, which has been found to be the best explosive for detonating dynamite. The fulminate charge is a very powerful explosive very sensitive to friction, lows or heat and very poisonous. When exploded it has an intense local action, shattering things in its immediate vicinity, but not extending very far away from the explosion. This kind of detonator is intended to be exploded by a spark from burning fuse.

Jan 1, 2014

By Thomas E. Ricketts

Occidental Oil Shale Inc. has spent the last eight years at its Logan Wash. mine near DeBeque, Colorado, developing its modified in-situ oil shale process for obtaining oil from oil shale. Modified in-situ technology involves large underground chambers, or retorts, which are formed by mining out a minimal volume of rock to allow explosive expansion of the surrounding rock into tile mined void volumes. The resulting rubblized retort volume must contain a fairly uniform particle size distribution and void distribution to permit maximum oil recovery during subsequent in-situ processing operations. The more uniform the rubblized volume of particles, the more oil recovery obtained during processing. The processing involves first igniting the top of the retort and then. injecting air into the top of the retort to drive the combustion front downward through the entire rubblized volume. The oil is continuously collected at the bottom of the retort during the processing.

Jan 1, 1981

By Rachel E. Gooding, George C. Emmett, David R. Bradley

The United States (U.S.) Department of Homeland Security (DHS) Directorate of Science and Technology (S&T) is using a probabilistic risk assessment (PRA) approach to evaluate the risks from terrorist use of explosive materials against the Homeland. A similar approach is currently being used to evaluate the risk from terrorist use of chemical, biological, radiological and nuclear materials.

Jan 1, 2017

By Cristian Castro, Patricio Gomez, Jason Furtney, Augusto Lucarelli

Understanding the effect of blast-induced damage on wall stability is critical to safe and economical operation of a large open pit mine. In this paper, a numerical modeling methodology is used to investigate damage to rock at distances of greater than 10 m (30 ft) from a blast. Two applications of the model are demonstrated. First, the method is applied at a zinc mine to investigate the effects of pit blasting on underground stopes. The model predictions are compared with the scaled distance formula. Next, the model is used to investigate a common problem in which unfavorable jointing creates a rock wedge on the bench above a blast. The numerical predictions of wedge stability are compared to the wedge energy model described by Wong & Pang (1992).

By Cristian Castro, Patricio Gomez, Jason Furtney, Augusto Lucarelli

Understanding the effect of blast-induced damage on wall stability is critical to safe and economical operation of a large open pit mine. In this paper, a numerical modeling methodology is used to investigate damage to rock at distances of greater than 10 m (30 ft) from a blast. Two applications of the model are demonstrated. First, the method is applied at a zinc mine to investigate the effects of pit blasting on underground stopes. The model predictions are compared with the scaled distance formula. Next, the model is used to investigate a common problem in which unfavorable jointing creates a rock wedge on the bench above a blast. The numerical predictions of wedge stability are compared to the wedge energy model described by Wong & Pang (1992).

Feb 1, 2020

By Robert B. Hopler

"The story of packaged explosives begins with the use of black powder (also called gunpowder) in mining. Although discovered in the 13th century, it was not until 1627 that the first records of use in mining is recorded. It took until the early 1800's before its use began in underground coal. Althougha free-running, granular material, its recommended (and safest) manner of use was for the miner to pour it into ready-made or onsite formed paper bags prior to insertion into the borehole. This was absolutely necessary in horizontal or upward-slanting holes."

Jan 1, 1991

By Patrick D. McLaughlin, C Fordham

"The project outlined in the accompanying paper was to densify beach sands on the pond side ofa tailings dyke to the strength required for future dyke construction, This was to be achievedthrough the detonation of relatively small explosive charges in the sand to cause settlement intoa denser state."

Jan 1, 1992

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 Jorge Cárdenas, Piero Mejía, Diego Gamarra

The present case study details the solution to a complex situation in a mining operation, involving the challenge of expanding the tailings storage facility in high-criticality areas adjacent to electrical rooms that provide continuous power to the entire mining process, including water pumping and drainage systems. For this purpose, blasting is required to prepare the construction areas for the new expansion facilities. Upon deciding to proceed with blasting, a comprehensive engineering assessment was conducted to ensure operational continuity without impacting the process, while generating sufficient fracturing in the rock mass to allow extraction with auxiliary equipment. Support from specialists through the Technical Assistance area was requested, and a detailed evaluation was carried out through advanced studies. Field vibration studies were conducted to define attenuation models and characterize the rock mass in the sector. With this information, simulations were carried out using predictive and probabilistic models with Monte Carlo methods to select delay charges and optimal timing for reducing vibration levels and increasing frequency levels. With these measures, the three blasts conducted near the Gas Insulated Substation room, which had distances ranging from 30 to 100 meters, produced the following results: • Vibrations; The three blasts conducted at distances of 100, 30, and 50 meters recorded vibration values of 5.3, 40.2, and 9.5 mm/s, all of which were below the maximum vibration level of 50 mm/s set by the projects area. According to the USBM RI8507-OSMRE standard, all values for Peak Particle Velocity (PPV) and frequency were below the permissible limits. • Flyrock; Through filming and post-blast inspection, it was confirmed that the ejections were within the safety zone. • Fragmentation; The results obtained showed a maximum overbreak size of 1.5 meters, allowing the broken material to be moved effectively.

Jan 21, 2025

By Donna Kliche, Charles Kliche

It has been previously documented that various weather conditions such as wind direction and speed, cloud cover and, especially, temperature inversions can significantly affect the overpressure generated by a blast event (Siskind et al, 1980; Oriard, 1999; Siskind, 2000). The overpressure can be magnified downwind and reduced upwind; a change in the regular profile of temperature with elevation can magnify or focus the sound intensity at some distance from the blast event.

Jan 1, 2011

By K. Best, D. Conn

The US Army Corps of Engineers KY Lock Project in western Kentucky presented the blasters and vibration consultants with a set of unique challenges. The blasters on this project were faced with difficult geology and joint set orientation and sequencing of blasts opposite from what the explosive engineer/blasting specialist had recommended. Combining these issues with strict vibration and air overpressure specifications, blasting as close as 7 feet (2.1 meters) from a new lock wall, site topography that influenced the air overpressure, limitations on seismograph geophone placement that led to anomalies in seismograph recordings; surprising lessons were learned by everyone involved in the project and it is the authors’ goal to share this valuable information with everyone in the blasting industry.

Jan 1, 2024

By Ruilin Yang

Explosive blasting is a widely used method for rock breaking, recognized for its energy efficiency and cost-effectiveness. Despite its advantages, the efficiency of blast energy can vary significantly between different blasts. This paper introduces a new blast efficiency index to assess the energy efficiency of rock blasting, incorporating factors such as explosive consumption, the energy required for fragment surface generation (based on fragment size distribution), and the strength reduction of rock fragments due to blasting. Several examples presented in this paper demonstrate the calculation of the blast efficiency index using data from the literature. The findings indicate that blasting may be the most efficient method for rock breaking compared with direct mechanical techniques of rock breaking used for excavation. On the other hand, blasting is much less efficient compared with the controlled fracturing, such as the cleavage and fracture toughness testing, which highlights the significant potential to further enhance the efficiency of explosive energy usage for rock fragmentation during blasting. The proposed blast efficiency index can be integrated with advanced blast modeling techniques to optimize blast designs, thereby increasing the effective utilization of explosive energy for rock fragmentation and fragment strength reduction.

Jan 26, 2026

By Matias Suarez, Diego Zenteno

It is known that the introduction of electronic timing in the sequencing of blasting has changed the vision and way in which mining is developed. It is possible to deal with more complex and sophisticated drilling designs, without compromising productivity or safety. It has been shown in various studies, that a correct timing of the blasting provides an improvement in the improvement of the processes downstream, due to a decrease in the resistance of the resulting fragments coming from the interaction of the waves generated in the detonation of explosive loads. On the other hand, it has also been shown that variations in the composition of a same type of explosive, has a significant influence over the resistance of the blasted material, also the energy associated to break it, affecting directly its degree of fragmentation. This paper is aimed to display the new advancements of blasting engineering done in different mining sites throughout the country, associated to electronic sequencing, energy of the explosive and its impact on the fragmented rock. This document explains how to define and implement selective sequencing in the blasting in order to promote the propagation of cracks, therefore impacting positively the productivity through the use of the LaGrange diagram. The LaGrange diagram is a very convenient and illustrative method to present the dynamic behavior associated with wave and crack propagation (Rossmanith. H, 2002). This study focused on the methodology of the formation and measurement of seismic pulses, through the rock massif. For this purpose, seismic pulses were acquired in the field and then, the different dynamic phases of the wave were molded mathematically, with the purpose of favoring the coupling between them.

By Carlos Enrique Arroyo Ortiz, Jadir Pedro Alves

This paper presents some of the results obtained during the research work about the use of technologies and digital transformation in the process of rock drilling in open pit mines. The use of automation presents itself as a disruptive factor and a driver of improvements that provide sustainability in rock drilling. Seven main operational parameters were utilized to combine measurement while the drilling (MWD) with other information generated by the equipment during hole drilling, in six different lithologies in an iron mine, located in the central region of Minas Gerais in Brazil. Adjustments and corrections were made to the data collected in order to minimize external influences other than the rock itself, to ensure the effectiveness of the analyses. Finally, we sought to compare the performance of the drilling process in manual and automatic operation modes. Thus, making it possible to show the efficiency and impact on the sustainability of rock drilling operations in open pit mines.

Feb 6, 2023

By Matias Suarez, Diego Zenteno

This paper is aimed to display the new advancements of blasting engineering done in different mining sites throughout the country, associated to electronic sequencing, energy of the explosive and its impact on the fragmented rock. This document explains how to define and implement selective sequencing in the blasting in order to promote the propagation of cracks, therefore impacting positively the productivity through the use of the LaGrange diagram. The LaGrange diagram is a very convenient and illustrative method to present the dynamic behavior associated with wave and crack propagation (Rossmanith. H, 2002).

Feb 1, 2020

By Iván E, Alex Araya Jofre, Jean Guiroux Toro, Eduardo Valdés Guerra

Currently, it is important for companies to have controlled mining operations and adhere to production schedules. To achieve this, one of the key factors is maintaining high reliability in the P&T process, primarily the opening of ore stope, which could be delayed due to any unplanned or uncontrolled problem. These ore stope opening processes, whose main activity is generating free face, are a very important pillar for future mine planning. The possibility of ensuring their opening brings a series of downstream benefits: safety, economics, productivity, and compliance and adherence to plans. The process under discussion consists of developing free faces in a single blasting event. This will help us leverage greater reliability for overall production operation plans, reduce construction times, and open up opportunities for downstream improvements in the production process, considering technical factors in P&T designs. This study presents a developed methodology and shows the results of its implementation in ten (18) single-event free face blasts. The analysis includes cavity geometry, geology, rock qualities, drilling deviations, and the blasting strategy implemented for each event. The methodology used considered material fluffing processes, the actual drilling trajectory, the initiation sequence, QA/QC during explosive loading, monitoring instrumentation (vibrations), and VOD recording, among others. As a result, out of a total of 18 free-face events blasts in a single event, 16 were successful and two achieved 90% efficiency, reducing the stope's production start-up time by 50% compared to current operations. By implementing free face blasting in a single event, there are savings in operating costs, increased productivity of the mining equipment, and improved adherence to production plans. For applications with greater heights of free faces, where blasting cannot be carried out in a single event, we should consider performing them in two stages using wireless detonators already available on the market for mining operations.

Jan 26, 2026

By C. Liley

Open cut blasting at the Ernest Henry mine has the potential to cause damage to nearby underground workings. This paper is a case study of the blast vibration management project which was conducted to ensure pit blasting did not adversely affect the stability of upper production levels or cause damage to the underground primary fan units.

Jan 1, 2012

By N. Rouse

Underground raises and slots are a vital part of underground blasting operations. Raises and slots are vertical shafts or openings used for ventilation, ore passes, or creating voids in stopes. In the author’s experience, raise and slot designs can vary significantly from operation to operation or even within a single operation, sometimes for reasons unknown. The results of the various designs can differ depending on drilling accuracy, geology, and the explosives used in the design. The purpose of this paper is to summarize the recommendations found in published literature on raise and slot design in one document, while incorporating some of the author’s own experience with optimizing raise and slot designs in underground operations. Some inspiration is also included from burn round designs; small versions of raises drilled horizontally in development blasting rounds. This document includes discussion points on drillhole diameter and depth, pattern design and relief requirements, explosive types and loading recommendations, and timing. Ultimately, this document can be useful to those looking to design a raise or slot blast for the first time or for those looking to improve on the results from the raise and slot blasts used at their operations.

Jan 1, 2024

By A. S. Tawadrous

This paper is an evaluation of Artificial Neural Networks (ANN) as a tool in the design of the geometry of surface blast patterns. The built model uses eight different parameters, which affect the design of the pattern. Those parameters are rock type, stratification, blasthole diameter, bench height, type of explosive, priming position, powder factor and fragmentation size required. The network was trained to predict burden and spacing of the blast pattern. The model was built and trained (back-propagation technique) using 43 case histories collected from the literature. The model has then been validated using 16 cases from operational quarries.

Jan 1, 2006

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