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By Matthew Graham, Tapan Goswami, Geoff Brent

In dragline coal mining operations, throw blasting is used for the controlled placement of overburden to maximise coal exposure rates or to minimise overburden removal costs. This may necessitate sacrificing thin coal seams, generally less than one metre in thickness, which are often present in proximity to the main coal seam. This represents not only a significant loss of potential revenue and profit but also a waste of a valuable energy resource.

Jan 1, 2010

By Richard Givens, Thomas Baginski

Technological advancements in warhead designs and implementations have driven the development of arrayed initiation networks of highly accurate, highly reliable, and extremely safe detonators. Recent development efforts have produced advanced Exploding Foil Initiator (EFI) based systems that have been adapted for civilian use in commercial blasting applications.1,2,3,4,5 This novel, high technology system promises multiple improvements and advantages over the manufacturing, transportation, tracking, storage, inventory and field operation of current detonator systems. Ultimately the insertion of this technology would result in fielding a Non-Energetics Based Detonator (NEBD). Insertion of complementary technologies into the detonator’s supporting systems would greatly advance current detonator hardware/software.

Jan 1, 2011

By Michael Laing

"Geology plays a critical role in many aspects of blasting, from fragmentation to wall control. One often overlooked component of blasting concerns blast results due to the effect of geologic features. The direction of blasting, with respect to strike and dip, can produce varied results, depending on thescenario. Working with geological features, as opposed to against them or without regard to them, can therefore dramatically improve blasting results. This paper focuses on the role of “geologic features”, which include joint-sets, natural fractures, and bedding planes (all of which are commonly referred to as “seams”) for the purposes of this paper. The goal of this paper is to promote understanding and mitigation techniques for various scenarios in which there are identifiable geologic features. Depending on the nature of these features (strike and dip specifically), blast design and pit advancement/development can be carefully considered to use make the best use of these features and optimize blast results."

Jan 1, 2016

By Thierry Bernard

Since the signature hole method principle has been described in the 80's, there has always been a lot of controversy about it. The theory is easy to understand but when it comes to apply it for predicting vibration level, optimizing timing to reduce PPV or shifting frequencies, it’s not always working as expected. Simulations show waveforms that don't make any sense or predictions that are far away from actual results.

Jan 1, 2012

By Richard A. Dick

Few topics in the blasting industry are more controversial than the proper riming procedure for large-diameter ammonium nitrate-fuel oil (AN-FO) charges, despite the considerable amount of research that has been done both in the laboratory and in the field. The January, April, and June 1975 issues of Emphasis on Blasting contain interesting discussions on priming (5). An ideal primer is one that will surely and efficiently initiate the AN-FO column at the correct location to assure optimum blasting performance. During the 20 years of AN-FO's existence, singlepoint priming, axial priming, multiple-point priming, thermal priming, and shock riming have all been advocated as the "optimum" method. This is not surprising because blasting specialists have often differed on even the most fundamental concepts. To define the optimum primer, we must know what detonation characteristics in the AN-FO column are most desirable. Again, authorities disagree. This paper will discuss conclusions of various studies in an attempt to clear up some of the confusion.

Jan 1, 1976

By A. S. Tawadrous

Fines are produced in any blasting application. Depending on the application, fines may or may not be a desirable product of the blast. In most quarry and construction applications, fines are considered an undesirable product since it does not constitute a sellable product and there are costs to the operation for disposal. On the other hand, in most open pits fines do not represent as much of a problem since the ore has to be crushed and ground after being blasted. Therefore, fines in such operations may reduce the energy consumed in the downstream operations.

Jan 1, 2012

By Tapan Goswami, Stephen Jeric, Geoff Brent

Highwall failures in large deep open cut mines have very significant safety and commercial implications. There are many factors influencing the stability of highwalls. The major influence is the interaction of the local geology with the shape of the pit wall. This factor is in the realm of the geotechnical engineer and is beyond the control of the blasting engineer. However, a secondary influence is the blastinduced damage to the wall. In most open cut metal mines the blasting strategy to control this damage involves the use of separate production and trim blasts bounded by presplits at the final wall.

Jan 1, 2011

By Ulrich Leiste, David M. Fox

This paper presents the results from small scale testing aimed at measuring the loads on a rigid target due to the detonation of a buried mine. The aim of this research is to find how the impulse delivered to the target varies as the air filled void volume fraction within the soil changes.

Jan 1, 2013

By Ricardo Chavex, Adrien Letellier

Flyrock remains one of the most critical issues in open-pit blasting. Despite the significant improvements made with modern surveying methods, the necessity remains to define sensible danger zones around blasting areas. Therefore, many semi-empirical models predict flyrock distances based on trajectory calculations and probabilistic adjustments. However, most are merely based on nominal parameters, even though a considerable amount of precise data is nowadays available thanks to modern measurement techniques using lasers, GPS, drones, and probes. These data provide accurate information about the actual field circumstances of a blast concerning geometry and rock-mass conditions. So how can we use and integrate them into existing flyrock models? The answer to this question can significantly improve the accuracy of flyrock prediction models and enhance safety. This paper will present a method to adapt existing models to actual field data using appropriate software and digital tools during the blast design process. In addition to calculating a more pertinent danger zone perimeter, this method provides an efficient and practical tool that helps prevent flyrock incidents. Indeed, it allows the blast designer and shot firer to be warned if there is a hazardous critical deviation due to local conditions. Moreover, it also enables blasters to communicate better and share the visualization of the blast-specific evacuation zone. The paper will also discuss how this method can be calibrated and how it has been used to analyze some actual flyrock incidents.

Jan 21, 2025

By Francisco Sena Leite, Raquel Sobral, Vinicius Gouveia de Miranda, Céu Jesus

"This document investigates a newly developed technique with the objective of improving terrain triangulation models (horizontal/sub-horizontal and vertical/sub-vertical terrains), mainly blast free faces. The algorithm uses multi-linear regressions to generate the best point cloud projection plane by applying the residues modulus minimization so as to create the finest 3D triangulation model. A change of base is required to create a new set of coordinate axis and generate completely new projection planes. The projection plane residue analysis is inferred in order to avoid or reduce the outlier points. The dataset is composed of 12 terrain models obtained from photogrammetry and a 3D Laser equipment thatgenerates georeferenced cloud points. This new technique is validated by the analysis of the obtainedcritical burden by the improvement of the general aspect view of the terrains and the capacity of outlier’s detection. The result and the quality of the algorithm demonstrates the improvement in the triangulation mesh, reducing errors in the calculation of over/under burden, free face volumes, cavities and, therefore, in the estimations of clearance/safety distances."

Jan 1, 2017

In the March/April 2006 issue of the Journal, we published an ethical dilemma called “Blowing the Whistle.” We received many interesting responses to the article as requested. Some of the responses are printed here. We’ve also included “Blowing the Whistle” again in this issue as a refresher on page 37. Dear Editor, It is in my own personal belief that it would be extremely important if I were the blaster to take the following steps. 1. Hold an immediate emergency meeting with the contractor to convince them to stop work at this point.2. This meeting would need to be held with all powers that be in this construction company. This helps eliminate the hearsay (excluding the farmer). 3. Explain the entire situation to the contractors as it has been presented to the blaster by the farmer. 4. Recommend calling in an engineering or geological firm with the expertise to investigate this matter immediately, and take all immediate action based on findings. 5. Follow up with farmer allow him to speak, (a.k.a. vent) and assure him proper steps are being taken to come to resolve this matter. 6. Be a good listener, and communicator with the farmer while investigation is being conducted. 7. Should the contractor not want, or take any of these recommendations, the blaster himself and his company should question even working for this company ever again. This in itself would not be the class of people we would want to be associated with EVER.

Jan 1, 2007

By Frank Hirthammer

"Nowadays, security in the lifecycle of explosives is more important than ever. Terror attacks all over theworld pushed the EU to decree a Commission Directive for the identification and traceability of explosives that set a series of requirements for involved manufacturers, distributors and end-users. The challenge was to find and implement a track and trace system for all concerned European companies byApril 5, 2015. Since then, countries worldwide have followed this example and implemented similarregulations."

Jan 1, 2017

By Francisco Leite, Tomi Kouvonen, Bianca Saraiva, Vinicius Miranda, Auã Oliveira

One of the main challenges facing mining engineers is to draw up a plan that can be implemented in a timely manner, taking into account the operational variability of the mine’s production processes. These plans are often drawn up based on deterministic modelling (provided there are a set of known inputs that will result in a single set of outputs), when in truth we are talking about stochastic events (the cycles involved behave like random variables and their nature may be studied and reproduced). The result of using this kind of methodology can lead to non-optimized intuitive choices, which may harm the long-term targets defined by the planning team. Based on this principle, this document investigates the simulation of the rock fragmentation process in an open pit mine to assess the stochastic behavior of the loading and haulage operating cycles. The data assessed by the simulation process were the total costs of these operations in function of the powder factor. Based on a sample set data items, it was possible to check the probability distribution of the event as a Poisson distribution, applied to the loading and haulage cycles. The simulation consists of the repeated sequenced reproduction of these events (Monte Carlo simulation), in order to find the configuration that best fits the loading and haulage operations. By integrating these systems, it was possible to better understand the influence of the blasting in these operations, and as such to reduce the associated costs.

Feb 6, 2023

By Javier Illanes Pizarro, Gustavo Huerta Valer, Jorge Cárdenas Miranda

Bench stability is the basis of sustainability in an open pit mining operation. Taking care of the pit walls while maintaining fragmentation results can prove a challenge. In this study, technical proposals have been developed for extra hard rock mass (UCS>175MPa) with presence of unfavorable structural planes in high copper grade zones. The base case shows low compliance of fragmentation results and a significant loss in berm width, with over size boulders causing low primary crushing rates. Paradigms in current drill and blast design were overcome to improve fragmentation results and achieve objectives.

Feb 6, 2023

By Andrew Theobald, Peter Dare-Bryan, Trevor Byers

The use of advanced modelling techniques and the timing flexibility of electronic initiation systems allows for unprecedented control over blast outcomes as shown in several complex blasting problems experienced by the open pit operation Xstrata Ernest Henry Mine (EHM) in north-west Queensland, Australia.

Jan 1, 2010

By Douglas R. Simms

O & G Industries, Inc. owns and operates a number of rock quarries within the State of Connecticut. These rock quarries are surrounded by residences and commercial neighbors who have concerns related to blasting. In addition, local commissions which issue the mining permits to O & G are required to hold public hearings, prior to issuing the annual permits each year.

Jan 1, 1994

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 W. L. Saunders

RBH Note: In the early days of drill & blast tunneling the jobs utilized large crews of drillers and muckers. Advance per round was limited (typically around four feet) but two rounds per 8-hour shift were expected, around the clock. The scene after a shot must have been chaos, with the muckers expected to quickly make space for the drill setup. Makes one wonder how much time was allowed for the smoke and fumes to clear. Note the headgear of the tunnelers.

Jan 1, 2011

By Jon Hurt, Brent Meins, David Vardiman

"Two test blasts were conducted at the Sanford Underground Research Facility to establish optimum blast designs and to limit blast effects on existing research rooms and equipment in preparation for the largest deep underground excavation in North America. Located on the 4850 Level (4,850 ft below the surface)at the former Homestake Mine in Lead, SD, this excavation is part of the U.S. Department of Energy’sLong-Baseline Neutrino Facility that will house particle detectors for the international Deep Underground Neutrino Experiment hosted by Fermilab. A large array of seismographs was deployedthroughout the 4850 Level to measure ground vibrations and airblast pressures in tunnel drifts and in lab spaces."

Jan 1, 2017

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