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By Peter Moser, Andreas Grasedieck

In modern rock blasting it is becoming more and more important to achieve a certain specified fragmentation. This means that the rock particles formed as a result of the blast should conform to a desired particle size distribution. An important issue with respect to achieve a desired blast result in terms of fragmentation is both the availability of models for the prediction of the characteristic of the particle size distribution of blasted material and the determination of the energy necessary to achieve a certain fragmentation status. Within the research project “Less Fines” funded by the European Union under project reference G1RDCT200000438, the latter has been addressed by the Department of Mining Engineering& Mineral Economics of the University of Leoben. For that purpose fragmentation results from lab scale blast tests have been analyzed and the relationship between the specific charge used for the blasts and the resulting specific surface of the fragmented material has been examined. Linear relationships between the specific charge and the specific surface of the resulting fragmentation were found for various types of rocks to apply over a range of 10 for the powder factor.

Jan 1, 2004

By Jacob Miller, Phillip Mulligan

"Measuring the blast pressure associated with an explosion suspended above the ground (Free Air Burst)is a common research objective in Explosive Engineering. Theoretically, the shockwave from a Free Air Burst (FAB) configuration expands radially and the shockwave is assumed to have a smooth (uniform) shock front. The way in which the FAB explosive charge is suspended, packed, and the charge geometry can affect the shockwave expansion. These factors can generate a non-uniform shock front. As the scaled distance between the pressure sensor and the FAB increases, the shockwave expansion averagesnon-uniformities into a uniform shock front, at which point the FAB suspension system becomes less critical than when the scaled distance is “close-in” (Z <3)."

Jan 1, 2017

By Visitor Makiyi, Chris Batten

Poor coal recovery due to coal damage or loss caused by blasting can have a significant impact on a mining operation. Increasing coal recovery by reducing blast damage can provide a significant opportunity for coal mines to maximise their revenue and reduce their operating costs. This paper provides details on advanced drilling and blasting techniques used throughout the coal industry globally to prevent coal damage and movement during blasting. Typical coal loss and damage mechanisms are explained, along with how each of the applied techniques works to minimise the impact of each mechanism. Key requirements for a coal loss reduction program are detailed with typical design parameters used for each of the methods discussed. The positives and negatives of each method are also provided to enable comparisons and help determine suitability for a particular coal mining operation.

Jan 21, 2025

By Roger Favreau, Patrice Favreau

Without blasting there can be no roads, no hospitals, no factories, not even foundations for homes. Yet in 1960 the only way to design a blast was by trial/error. By comparison, bridges were already designed by calculations before being actually built. This was possible because equations based on the fundamental principles of science existed with which all the stresses in the bridge could be calculated. In 1960 no equations based on the fundamental principles of science existed with which the mechanisms that take place inside the rock mass during a blast could be calculated. Since then the main author made it the objective of his research to seek such equations, and to validate that they gave accurate answers by means of experiments in the field, experiments made in co-operation with mines, quarries and the explosives industry; results have been reported in some 90 publications.These equations now deal with essentially all aspects of a bench blast: the intensity of the shock wave and the fragmentation size distribution throughout the rock mass; the movement of all the fragments into the muck pile; the fly rock and vibrations from the blast; etc.; are presented examples of such equations. They are now assembled into a computer simulator called Blaspa accessible on the Web, with which one can design a blast just as a bridge is designed. An example is presented. The reason to design a blast by simulations rather than solely by trial/error is that if it leads to damage, it is only after the actual blast that the blast design is realized to cause damage. If however the blast design had been simulated before the blast, then the risk of damage is identified before the blast and is prevented by redesigning the blast. Examples of such situations are presented. The need to a void damage is very necessary because the public is becoming opposed to blasting. When a blast does cause damage, and people learn that the blast was designed solely by trial/error even though simulation was available and would have prevented damage, they become even more strongly against blasting; they may succeed in getting a quarry closed. Their objections to unchecked blasting are not unreasonable, especially as simulating a blast with Blaspa on the Web is a very simple procedure.

Jan 1, 2013

By Rajesh Sonkar, Sanjeev Kumar

The deployment of Dragline machines in opencast coal projects involves huge capital expenditure as well as operating costs. The mine operators always endeavor to ensure smooth excavation of material by the Dragline machines while meeting the major objectives of safety, minimal disturbance to environment and optimal operating costs. Optimization of fragmentation through well designed blasts is fundamental in meeting part of the objectives is good fragmentation of rock or mineral proposed to be lifted by the Dragline machine. If the overburden lying over mineral is not properly fragmented, it may result in formation of ‘Toe’ the removal of which is the most arduous task in opencast coal mines. The mine operators always endeavor to achieve best possible results in blasting to ensure smooth operation of the high cost Dragline Machine. However, despite continuous efforts by the blasting engineers involved in bench blasting for the machine, the formation of ‘Toe’ is an ever nagging problem faced in large opencast coal projects eventually reducing the overall operational efficiency of mining.

Jan 1, 2011

By Natalie Zeleznik, Brian Hawkins, David Bradley, Rachel Gooding, Patrick Wilson, Brian Somes, Kevin Wegman

"To perform a probabilistic risk assessment (PRA), a method of quantifying the risks associated withinfrequent high consequence events, consequence models that generate representative estimates of human health consequences for a wide variety of representative scenarios are commonly used. Criteria that suitable models must possess include: (1) input requirements necessary to generate large volumes ofprobabilistic simulations; (2) the capability to output injuries with the necessary details and resolution;(3) the ability to capture the variety of different scenarios inherent in an assessment; (4) acceptable cost and computational requirements; and (5) sufficient stakeholder buy-in for community acceptance."

Jan 1, 2017

By Kim Henley, Chris Batten

This paper discusses the use of the Orica WildFireTM flyrock model to help mining operations in Australia and Asia minimise blast exclusion zones for equipment, increasing utilisation and productivity and delivering downstream value

Feb 1, 2020

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 Lawson J. Taylor, Paul N. Worsey

Recent reputable evidence conclusively indicates that conventional chemical delay elements in delay detonators are notoriously inaccurate and can thus seriously affect blasting efficiency.

Jan 1, 1983

By W. Reisz

Dealing with misfires can be one of the most difficult and serious issues that blasters must confront. Most of us will - at some point, have to deal with a misfire situation.

Jan 1, 2009

By John Petty, John Loviza

Single sentence describing content-- "The best ally an Explosives Engineer can have in a court of law is a regulations enforcer stating all codes and standards were met on a jobsite".

Jan 1, 1996

By Rolf Koenig

A fire aboard a vessel transporting explosives and detonators manufactured by Dynamit Nobel endangered the cargo. Due to the special safety properties of the detonators, no mass detonation occurred.

Jan 1, 1989

By Paul D. Dupree

This paper discusses the drilling and blasting techniques used in blast casting at a large western coal stripping operation.

Jan 1, 1986

By Mark William Withey

Blasting safety in surface mining is a necessary industrial goal. Proper techniques and disciplines exercised during the blasting process enhance the probability of achieving that goal.

Jan 1, 1995

By Lyle Avey

For the purpose of this paper, testwork and general pre-splitting practice will be discussed for the Chimney Creek Mine.

Jan 1, 1990

By Tom C. Palangio

Traditionally, mines and quarries have lacked a practical method of describing blast results. Adjectives such as good, fair, or poor do little to define performance, and sieving and/or counting particles was too costly and time consuming to be considered a viable alternative.

Jan 1, 1995

By N H. Maerz

The digital image analysis program WipFrag has been developed under contract to INCO for use in quality control of underground blasting operations. This paper outlines the relevance of fragmentation to underground mining, the hardware and photography requirements, and key features and operating principles of the software.

Jan 1, 1995

By Eduardo Gonzalez Fernandez, Jaime Rios Vazquez

This report substantiates the connection that always exists between explosives and vibrations and draws attention to low frequency vibrations, which are the moat dangerous for the structures affected.

Jan 1, 1986

By Stanley L. Lippincott

A number of Federal and State agencies require formal training for blasters. Federal agencies often specify the need for initial training involving all job responsibilities as well as periodic refresher training to assure adherence to current operating procedures. failure to provide and document such training can result in substantial penalties.

Jan 1, 1995

By Melvin A. Sannes

The explosives industry is recognized as one of the most dangerous occupations in the world, yet it is rare to see actual training procedures. As our industry becomes increasingly technical, it is imperative that we train the personnel in OUI industry properly.

Jan 1, 1999