Search Documents

By Francisca Tapia, Jorge Blázquez, Paulo Couceiro, Patricio Vergara, Luis Manriquez, Luis Martínez, Juan Navarro

Efficient energy transmission is critical for effective rock fragmentation in open-pit blasting. However, in zones with highly fractured or soft rock, mismatches in acoustic impedance between the explosive and the rock can lead to significant energy loss. These mismatches reduce fragmentation efficiency and, when energy input is increased to compensate, can trigger unintended side effects such as NOx fume generation. This paper presents a novel methodology that integrates the Fragment Size Energy Fan model with acoustic impedance theory to dynamically optimize explosive energy delivery. A redefined impedance formulation captures volumetric energy transfer and enables the calculation of a Rock Impedance Factor (RIF), calibrated through non-linear regression. To operationalize the model, rock impedance is estimated using the X-4Traits Model—a meta-learning algorithm that interprets Measurement While Drilling (MWD) data from both autonomous and manually operated drills to produce high-resolution, spatially distributed impedance maps. The methodology was calibrated and applied at Minera Escondida Limitada (MEL), using data from over 218,447 blastholes and 526 blasts. Two case studies illustrate its application: Expansion 1 demonstrates improved fragmentation consistency and a 10.7% reduction in powder factor by aligning explosive energy with local impedance variations; Expansion 2 highlights the model’s utility in managing NOx emissions in fractured zones by optimizing energy distribution and confinement without compromising fragmentation. This impedance-based framework provides a robust tool for improving fragmentation outcomes, optimizing energy use, and enhancing control in geologically variable blasting environments.

Jan 26, 2026

By Cory Loukides, Cathy Aimone-Martin

Blaster training manuals used by the Office of Surface Mining (OSM) and others are outdated and cumbersome. A new approach has been developed using Microsoft PowerPoint with a Visual Basic overlay to produce modules on CD’s that present state of the art blasting techniques. The education modules contain enhanced information on topics such as explosives and initiation products, blast design, drilling, and vibration control. The content is based on safe practices and illustrated with numerous photographs and movies. Review questions, complete with explanations for incomplete answers, enhance the learning process and keep the blaster involved. The benefits of using an electronic format include the ability to continually change and update the training modules as new products, technology and applications become available. In addition, the blaster can work at home in preparation for class work and may reduce the time away from the job. This poster session presentation will allow potential users to view and take part in the evaluation of these modules.

Jan 1, 2004

By Norman Paley, John Kells

The climate and location of the Red Dog Mine present several challenges to blasting operations. The mine is located north of 68º latitude, in an area of continuous permafrost. Ground temperatures are below freezing year-round and air temperatures range from -40 to 70°F (-40 to 20°C). Because there is no overland access to the mine, the entire year’s supply of bulk explosives, approximately 7,000,000lbs (3,175,000kg) is shipped in by barge during the 100 day shipping season when the port is ice-free. The first week in July is the earliest that new product arrives at the port. Emulsion usage is maximized from mid April through October when surface water fills the blastholes during drilling. This necessitates that a considerable portion of the bulk explosives are stored for 10 months or more before usage. The emulsion is routinely pumped from the ISO containers at temperatures of 20ºF (-7°C). The mine engineers conducted a testing program during the 2001-2 blasting season to identify the bulk explosives best suited for the conditions at the mine. A secondary goal was to decrease the usage of sensitized emulsion, as this is the most difficult portion of the explosives order to ship. To ensure repeatability when transferring the results to the day-to-day blasting operation, the majority of the testing was incorporated into normal blasting operations in the field. The mining methods used at Red Dog Mine make direct fragmentation analysis impractical and performance testing in the field relied primarily on VOD measurements. The products were also tested for their ability to be pumped in cold temperatures.

Jan 1, 2004

By Denard Brandt, Isidro Martinez, Greg Baker, Laura Slattery, Teddy French

The Dos Pobres Mine is a copper oxide heap-leach mine located near Safford, Arizona. Mine production is 180,000 tons (163,293 tonnes) per day with a stripping ratio of 2:1. During the startup phase of the mine, the required fragmentation size was easy to achieve as the ore was highly weathered and fractured near the surface. As the mine depth increased, the proper fragmentation size became harder to achieve due to less weathering and different rock types. Because copper recovery increases as crusher product size decreases, achieving the appropriate product size at the crusher is the operating priority.

Jan 1, 2010

By Jeremiah Cohn, Rachel L. Bauer, Catherine E. Johnson

Water is frequently used in explosive applications to increase explosive performance and reduce air overpressure. Water tamping can enhance cutting abilities of shaped charges in demolition and increase impulse of kicking or breaching charges. In explosive disposal, water is used to suppress air overpressure and reduce noise. Despite its widespread use, the specific effect of water placement, whether in front of or behind the explosive, has not been studied. This work evaluates the directional effects of water placement on blast performance using 400-gram sheet explosive charges in five configurations: no water (control), rear-only water (tamped), front-only water (pushed), water on both sides (confined), and a thin front-and-rear water layer (low mass confined) to assess reduced mass effects. Water was sealed in plastic bags and held in position with custom 3D-printed cages to ensure consistent geometry and contact. A modified ballistic pendulum consisting of a hanging steel W-beam was used to evaluate impulse transfer, with high-speed video capturing swing velocity. Air overpressure was recorded using a seismograph microphone. Rear-only water (tamping) increased beam swing velocity by 69% over the control while confinement with water on both sides increased performance by 12% at a 2:1 water-to-explosive ratio and by 50% at 4:1, though it still underperformed the tamped-only configuration. Pushed water alone did not increase beam momentum and reduced tamping effectiveness by 19% when combined. Seismograph microphone data showed that pushed and low mass confined water configurations produced some of the highest air overpressure levels (up to 139.2 dB), while tamped and control charges produced lower levels (~134–136 dB), suggesting that pushed water may amplify, rather than mitigate, air shock transmission. These findings show that water placement has a strong directional influence on blast dynamics: water behind a charge enhances energy transfer to the target, while water in front provides limited or potentially counterproductive mitigation. This study advances understanding of water–explosive interactions and will lead to more effective charge designs for breaching, disposal, and demolition.

Jan 26, 2026

By Mario Alvarez

Drilling with tricone drill bits is widely used in the mining industry with a direct impact on drilling safety and costs, however it can be challenging to implement a new supplier of tricone drill bits, choosing a new model of this accessory due to the normal variations of the rock mass or even due to the acquisition of new and modern drilling equipment for open pit blasting operations. This article identifies the most common mechanisms of failure in productive drill holes of tricone drill bits, both in open-pit coal and metal mines, in two South American countries. It also emphasizes the important issues that must be addressed for the optimization of the performance of these accessories, such as the correct identification of the rock mass, the drilling parameters, and the impact of autonomous drilling on new equipment with this technology. The article presents some of the successful actions to economically improve the performance of drill bits considering the close relationship in the field with the supplier's technical representatives and factory designers, as well as the commercial interrelationship between their respective business areas. The article concludes by discussing the future of tricone drill bit design development, its environmental management, and possible new advances in its manufacture.

Jan 21, 2025

By Orica

Unlicking the Possibilities ISEE Digital Detonator Workshop New Orleans, LA Wednesday, February 4, 2004

Jan 1, 2004

By Rob Lederer, Chris Batten

Traditionally coal model digital terrain models (DTM) are created from lithological information obtained from broad scale exploration holes. The grid layout and distance between holes means that models do not commonly display local variations of seam dip, faulting and shearing. Due to this, issues can often arise when designing the loading of blast patterns based on potential variances between model and actual coal seam locations. Many sites will often attempt to create more accurate models through the collection of data from coal edge pickups on highwalls and in blast faces, along with information recorded by drillers (touch coal holes) from both production and presplit holes for both the current and previous blasts.

Jan 1, 2012

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 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 Neal Lee, Braden T. Lusk, Brendan McCray

"Selection of a blasting agent for optimum performance is based on many variables. Often, a decision is made with regard to product cost and field testing. Defining optimum performance can be difficult, since downstream effects of fragmentation on loading, haulage, processing, and energy consumption are not immediately clear. Many operations are beginning to optimize their blasting programs “on the bench,” by utilizing information generated downstream at the loader and/or crusher. During the evaluation of a blasting agent, factors such as velocity of detonation, gas production, and sensitivity are typicallyconsidered. Alternatively, brisance (“the shattering power of an explosive material distinguished from its total work capacity”1) is not. Brisance affects the immediate area surrounding a borehole. Fractures produced here during the shock phase of detonation are believed to have an important effect on rock movement and fragmentation. "

Jan 1, 2017

By Harsh Kumar Verma

Blasting off-the-solid is the most commonly used method during development of galleries in Bord and Pillar method of underground coal mining. In this method, only P5 explosives are used with permitted delay detonators in accordance with the safety requirements stipulated by the regulatory bodies. Delay detonators made with pyrotechnic delay compositions have inherent scattering in their delay timings. It is desirable to use precise detonators to achieve better fragmentation, less vibration and noise. Overlapping of delay period is undesirable from production as well as safety point of view.

Jan 1, 2008

By Tassilo Baur

In the motion picture/television industry and to some extent in the entertainment industries in general, there is often a need to use energetic materials to create special effects as part of a production which travels, generally by truck. This can in certain instances create unique compliance challenges given that a production may change its filming location daily or even more often

Jan 1, 2009

By Norman Paley, Zachary Pickett

The Red Dog Mine is a high-grade zinc-lead mine located in northwest Alaska which began operations in November 1989. In June 2014 the upper half of a charge in a trim shot in the Aqqaluk pit deflagrated. No other holes in the area were observed to react and the remainder of the pattern was shot without incident. This was the only known case of a deflagration in the 25 years of operations. As part of the investigation into the cause of this incident rock samples were obtained from the area of this hole and from other areas in this pit.

Feb 1, 2020

By Daniel Scott

Mines have used explosives for economical fragmentation for many years. It can therefore be expected that the mining industry has thoroughly researched how to achieve the most efficient blast. However, there is still a large amount of iteration that must be undertaken before blasting at a mine site can be refined enough to allow for consecutively successful blast results. And then the geology changes. This paper will present an approach to blast design that considers production goals, geology, budget, and safety, and will contrast the proposed method with well established blasting theory.

Jan 1, 2012

By E. Contestabile, B. von Rosen

Recently, the Canadian Explosives Research Laboratory (CERL) completed its investigation of a truck accident, which involved 18,000 kg of commercial explosives, 13,000 kg of which was ANFO. Over the three years of the investigation unconfined burns of piles of ANFO were performed. In its final phase of the investigation, two burn trials were performed in an attempt to recreate the accident and the ensuing fire, to identify probable mechanisms that led from burning to detonation. Two full-scale tests were performed using complete tractor-trailers. In each test, the trucks were placed in a jack-knifed position with the majority of the explosives located on the ground in front of the trailer. The explosives were placed in a manner to provide maximum confinement and to maximize the possibility of explosion/detonation while remaining as faithful as possible to the perceived accident geometry. The tests were instrumented using thermocouples and video cameras and observations were made on the burning characteristics of the explosives, tractor-trailer and tractor-trailer components. In each test the explosives burned calmly for approximately 80 minutes. There was no evidence of explosion or of unstable burning. The heat caused several truck components to rupture violently. These included the tires, some engine components, the spring brake chambers and possibly the fuel tanks. Of these, the most violent were the truck tires. Although no quantitative data was gathered on rupture violence or fragment velocity, it is speculated that several truck components might produce fragments with sufficient energy to initiate heat-sensitised explosives under favourable circumstances.

Jan 1, 2004

By Corry Goumans, Ron J. Elliot

This paper discusses the challenges encountered in drilling and blasting of a small diameter shaft underneath a parking garage in historic Gastown, Vancouver, BC. This project involved drilling in a restricted headroom area, blasting in a confined space environment, and excavating using a novel vacuum technique. The 1.2m x 1.2 m x 8.5m deep shaft was required for installation of a hydraulic piston for a show lift. The project called for very accurate drilling through inter-bedded sandstone and siltstone within the water table. Development of a unique blast design was required for blast vibration control on a historic structure located just 15.8 meters away. The shaft was successfully completed without damage to any of the surrounding structures.

Jan 1, 2004

By Lon Santis, Bill Evans, John Tatom

Debris data from the Department of Defense Explosives Safety Board’s Project ESKIMORE full-scale explosives event test program are compared to quantity-distance (Q/D) standards and quantitative risk analysis (QRA) methods. The ESKIMORE test program involved quantities of explosives ranging from 1,000 to 60,000 pounds detonated in typically sized structures made of metal and concrete. Debris from these events was extensively surveyed and catalogued. The debris patterns from these events show varying degrees of directionality normal to the walls of the structures. These density patterns are overlaid an existing explosives storage site that is comparable to the test conditions. Analysis of the debris patterns in relation to Q/D standards shows that exposures located beyond the Q/D arc but along the normal to walls of potential explosion sites (PES) may have much higher debris density than exposures at the same distance on the corners of the same PES. Analysis of the debris patterns shows that predicted patterns using the QRA tool IMESAFR v2.0 closely match actual patterns. Additionally, IMESAFR based QRA methods are able to quantify the different risk levels of being exposed along the wall’s normal as compared to being exposed on the structure’s corner. Methods and decision making criteria to mitigate risk based on the directionality of PES debris are presented. Copyright ©

Jan 1, 2015

By Jesus Pascual, Benjamin Cebrian

A new Convention Center is going to be built in the millenary city of Toledo, right in the old city limits. The workings will need to excavate some 80.000 cubic meters of granite, which has, a trench-like structure already blasted for the construction (60 years ago) of a parking lot and a shopping area. Surrounding this trench, some few feet away, there are structures and buildings from the 16th century and remainings from previous times that need to be preserved from any damage caused by blasting. Because of this, a vibration analysis was designed according to the special characteristics of this work. Structures to monitor were located at several levels. It considered three different directions of study in order to evaluate the impact of vibrations of the structures located at three different heights of the granite trench. On top, the historical convent of Santa Fe, with some remaining from the 8th century (Muslim domination of the Iberian Peninsula), on the bottom, the Justice Hall of Toledo with 16th century walls, and, in the middle, a wall and a tower from times of the king Phillip II (16th century, the time of the Spanish Empire).

Jan 1, 2004

By Dave Weymer

Falling timber in BC has always been a hazardous job. Huge, often rotting trees and steep, rugged terrain combine to create difficult and dangerous conditions. Death and injury rates are among the highest of any occupation in North America. In BC, the men that head out, saw in hand, are called fallers.

Jan 1, 2013