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By D. Fry, S. Hunsaker

Ammonium nitrate in explosives and sulfides in reactive ground have the potential to react at ambient and elevated temperatures resulting in premature detonations. The Australasian Explosives Industry Safety Group (AEISG) published, in 2006, a Code of Practice1 for elevated temperature and reactive ground. This paper reviews the chemistry, general reactivity of various ground types, elevated temperature hazards, and testing protocols contained in the code, that are industry best practices for managing ammonium nitrate-based explosives in elevated temperature and reactive ground conditions. In addition to reviewing the 5th edition AEISG Code of Practice, data is presented validating the recommended sampling guidelines within the code. Dyno Nobel has been screening reactive ground samples and performing sleep time testing since the code of practice was first released. Test results demonstrate the effects of samples that are allowed to oxidize before testing and are shown to be subsequently less reactive and not representative of the actual hazards facing mining blasting operations. Results also show that for a given reactive ground sample, reaction times decrease with increasing temperature. Data also quantify the delay in reaction time given by inhibited products. These results emphasize the importance of proper sampling and preparation of samples to accurately characterize elevated temperature and reactive ground hazards. They also demonstrate the efficacy of inhibited products in managing these hazards

Jan 1, 2024

By Weiying Zeng, Shouwei Wang, Jinbei Zhong, Xiangdong Meng, Lingtian Meng

"Due to a drainage problem, the Lanzhou to Chongqing high-speed rail line had been out of service during the 2015 wet season, so a drainage tunnel is to be constructed for the line and required to be accomplished before the 2016 wet season. This drainage tunnel is only 5 meters below the line which is in service, therefore blasting vibration needs to be strictly controlled. This paper introduces all theapplied blasting methods, parameters and detonation throughout the entire project, finally bringing in the electronic detonator stagger phase technique and corresponding time difference for detonation."

Jan 1, 2017

By Tacio Ferreira

How state-of-the-art software, data analysis and communication applied to drilling and blasting techniques have have allowed quarries in the Midwest of the United States to improve results downstream

Feb 1, 2020

By Gordon Lovegrove, Jeffrey Leob, Dwayne Tannant

It has long been known that the combination of aluminum (AL) powder to ammonium nitrate (AN) / fuel oil (FO) can greatly enhance fragmentation or ultimately reduce the number of blast holes in a pattern. Decades of research have meticulously provided optimal AL:AN:FO ratios showing dramatic increases in energy output levels, yet widespread use of aluminized ANFO (ALANFO) has yet to replace the use of ANFO in the blasting world today. This may be due to the perception that the upfront, increased cost of materials deters the selection of this advantageously modified explosive. Researchers have explored this question and promote ALANFO by pledge of massive reductions in day-to-day operational costs. However, in these analyses there is a complete disregard for the external costs of the material; the environmental effects and sustainability considerations of the product. A holistic social cost-benefit analysis of ALANFO shows that an admittedly high-cost explosive does indeed provide an output which contains a wealth of operational savings in typical blast patterns. However, the immediate, on-site costs and savings do not define the limitations of this analysis. A complete comparison of the externalities including the environmental and sustainability considerations of the aluminum by-product life-cycle, and the environmental impacts of both the refinement of ammonium nitrate prills and the acquisition of sufficient fuel oil are also assessed. A savings of $216,000 / year through the use of ALANFO in one particular case study was recalculated to an increase in drilling and blasting costs of $188,000 when the external costs of aluminum, ammonium nitrate, and fuel oil are included analysis. The results of this analysis are intended to improve contractors? selection of explosives by providing additional societal and environmental factors into the equation, in preparation for an exponential global shift to greener business operations, while allowing them to remain competitive.

Jan 1, 2011

By D J. McLane, J T. Rathbun, B T. Lusk

The dynamics of explosive detonations are understood, however recreating a real-world, full scale scenario is costly. The use of a shock-tunnel allows testing to be done on a smaller scale, with the simulated effect of a large explosion. Analyzing explosive waveforms using this method can greatly reduce cost in testing blast resistant products, such as anti-terrorism devices, mine safety products, and military equipment. The purpose of this paper is to better the understanding of how the waveform characteristics resulting from an explosive detonated within a shock-tunnel differ from those in an open-air arena test. The variables of comparison between an open-air arena test and those conducted within a shock tunnel are peak pressure, impulse, shock wave velocity, and cross sectional shape of the shock front. Understanding how these variables differ, tests utilizing a shock tunnel can be conducted with a higher degree of accuracy and repeatability.

Jan 1, 2013

By James A. Bachmann, Christopher J. Gray

On December 26, 1994, at 1:00 am, Santa Fe Pacific Gold's Twin Creeks Mine experienced a major highwall failure involving over 2.5 million tons. The resulting effects of this slide were thousands of ounces of gold that were now deferred and an unstable wall above which made mining the slough material unsafe.

Jan 1, 1996

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 R. Alford

In the modern world of demolition safety is paramount and unnecessary or unquantifiable risks are not accepted (FasterCapital, 2024) and all risks must be kept As Low As Reasonably Practicable (ALARP) (BSI, 2017). This principle has led to a huge reduction in deaths in the last 50 years and the statistics continue to improve although this is starting to plateau (Beal, 2007). Under normal circumstances, this is now simply part of the normal way work is done and systems are in place to ensure both safety and economic profits are assured. What happens when the environment is less controlled and risks are unknown, such as after a natural disaster, war, an accident or a stand-up from a failed demolition attempt? A dangerous structure cannot responsibly be left alone with a fence around it so some action must be taken, but how can this be done safely and responsibly? An incident in Didcot, England in which half of a power station’s boiler house being prepared for an explosive demolition collapsed suddenly, killing four men in 2016 provides a useful case study of how technology, creativity and planning can be used to conduct complex demolition fully remotely to avoid any further risk to life.

Jan 21, 2025

By Michael Wieland

The thrust of this report is to overcome some of the technical deficiency in the scientific methodology that correlates the work output during a charge explosion to the resulting toxic fumes. Thermodynamic work-principle models yield (undissipated) shock and heave results for shooting underwater and in rock stratum with related toxic fumes. Underwater circumstances yield reliable test data for the work process, though questionable or no fume results. Work-output measurements in rock shots remain difficult if not intractable, though some fume reports exist. Underground tests with thick-wall metal pipe bombs yield consistent toxic fumes trapped within the test chamber. The work output, rendered as fragment kinetic energy, can be inferred from the well-tested theory of R. W. Gurney, originally designed for military ordinance. Therefore a work-principle model for cylindrical pipe bombs was developed to predict fragmentation work output and reaction-zone fumes, permitting the double comparisons to reported and inferred results.

Jan 1, 2010

By D. Rudenko, C. T. Aimone-Martin, J. K. Ratliff, I. G. Wong, J. Aiken, R. E. Burnham, T. A. Davidsavor

A small quarry blast was conducted with a maximum of 90 pounds per delay and shortly afterwards, area residents sensed ground motion and building shaking indicative of an earthquake. In addition, seismometers up to 500 miles (800 km) away recorded a magnitude 2.8 earthquake located in the area. Positioned in a seismically inactive area, southern Minnesota is not known for earthquakes. The earthquake was originally described by the USGS to be a surface blast at the quarry. Analysis showed that the earthquake occurred shortly (approximately seven seconds) after the quarry blast some distance away and well below the surface. This paper describes the evaluation of the “seismic events” including the blast, the following earthquake, initial governmental response, and provides the framework for assessing the relationship between the blast and the earthquake. The paper also discusses management of large volume claims from a complex event and presents a claims management strategy with best practices.

Feb 6, 2023

By Thierry Bernard

Considering rock fragmentation by explosive as the ultimate goal in mines and quarries, vibrations are definitely one of the main drawbacks faced by the Industry. If we can accurately predict vibrations level and frequencies, taking into account the whole set of the involved parameters, this will bring a major benefit to each of us, in our daily production process optimization effort. The model presented in this paper answers to this need thanks to a "holistic" approach of the vibration mechanism. By holistic, we mean that we approach the vibration effect (wave propagation) as a whole, by understanding all of the mechanisms that contributes to the process and comprehending how they are connected.

Jan 1, 2009

In all the industries that require blasting operations using explosives, there exists numerous unwanted side effects of the blast which may pose as environmental hazards. These hazards face prominence, especially in India, where there are very stringent rules and regulations governing the use of explosives. The environmental hazards associated with blasting operations as a whole can be tacked successfully to a certain extent depending upon the ultimate expectations of ,the post-blast effects and the limitations of the environmental obligations as specified by the authorities from time to time and from place to place. The main parameters which require attention to limit the post-blast results to the optimum level are ground vibrations, dust pollution, gas pollution, air blast effects, noise pollution & fly rocks etc.

Jan 1, 1995

By Bill Loviza, Jimmy Sanders

This report is not everything we would like it to be. Access to information concerning unresolved legal actions is a sensitive matter. Obtaining the information presented in this report was a challenge alone. The Tennessee Department of Commerce and Insurance, Division of Fire Prevention, the firms and individuals that elected to share information did so with various assurances of nondisclosure, confidentiality or anonymity. All those providing information did so with the expectation that the industry and ultimately the public would benefit from this effort. We offer special thanks to Assistant Commissioner, Fire Prevention, Emmett Turner, recently retired Director, Bomb and Arson, Dick Gardner and Director, Codes Enforcement, Randy Safer for support that made this endeavor possible. We make no claim with regard to being a scientific study. We did the best we could with available information. Our task was one of assembly, sorting and reporting. Where collateral information was available we used it.

Jan 1, 2004

By Joshua Hoffman, Braden Lusk, Kyle Perry

Shock tubes are used to simulate large-scale arena explosions without the use of full-scale arena sites that utilize large quantities of explosives. Instead, small explosive charges can be used to drive shock tubes. When this is done, the geometries of the explosive charges can alter the resulting pressure time curve. A common geometry chosen for the explosive charge is a sphere in order to be congruent with the spherical shockwave that emanates symmetrically in three dimensions from the detonation point. This paper reports on the findings from experiments that study the effects of altering the charge geometries and explosive types while keeping the TNT equivalency constant. Peak pressures and durations were affected by these changes. Directional phenomena are exaggerated by the use of certain charge shapes and detonation points. The speed of the detonation front in the explosive being greater than the speed of the shockwave in air played a critical role in the resulting pressure time waveforms. Waveform manipulation can be used to generate job specific waveforms that ultimately benefit the shock tube operators and their clients.

Jan 1, 2010

By Julio Cesar Barbosa de Freitas, Rafael Gonçalves Araujo, Túlio Soares, Jair Koppe, Augusto Ferraz Ribeiro, Pedro Barreto Garcia

This study thesis was motivated by the fact that it is of fundamental importance for open pit mining that the slopes initially have a geometry in accordance with what is proposed in the mining planning. This occurs because an inconsistency in this design can impact the operational safety and economic solutions of the mining project. These consequences can be explained by the fact that rock blasting close to mining limits requires specific study due to the attention required. Because, when this operation is not carried out properly, the mining plan in the mine may not be respected and may create risks to the operation due to the presence of unstable blocks on the slopes (Mackenzie). In this sense, Mackenzie (2004) cites pre-split, trim blasting and buffer as commonly used explosive blasting techniques that aim to limit damage beyond the projected wall. Therefore, Enaex Brazil realized the need to better understand the pre-split method. To do this, it is necessary to understand how the energy released during detonation is perpetuated in the rock mass when this technique is used and when it is absent. Thus, this analysis is based on a seismic study that allows the creation of vibration attenuation laws and an elementary wave damage model, which allows the local characterization of the rock. With this model it is possible to relate the peak levels of vibration during blasting and the extent of damage, but a critical level of vibration (PPVc) and its relationship with the Uniaxial Comprehension Resistance (UCS) are also defined for the start of fracturing and its level (McKenzie et al, 1995). And, mainly, this work aims to address a way to measure the pre-split filter potential by comparing the attenuation law with and without pre-split, ultimately knowing whether this finishing blasting is being effective, to understand the pre-split filter capacity.

Jan 21, 2025

By Tristan Worsey, John Henchion, Nathan Rouse, Yannick Lauras

"This paper presents an approach used to plan and evaluate drill and blast trials for a mine that currently mechanically excavates in-situ rock. The document presents the approach used to plan the trials, the key performance indicators (KPIs) that were necessary to evaluate the mining methods, the test matrix used during the trials, and the results of the trials. The trials, which occurred as part of an overall drill to mill optimization project at this site, helped to evaluate various blast designs using fragmentation results,drilling and blasting costs, and downstream costs. This project was unique in that (1) drill and blast methods were trialed on multiple rock types and various bench heights using a range of blasthole diameters and powder factors and (2) the load and haul costs were evaluated using a range of loading equipment, from 66 tonne (73 ton) excavators up to 250 tonne (276 ton) excavators. A ten year net cost financial evaluation of the material extraction alternatives was also prepared for the site management. Ultimately, the process of evaluating the drill and blast trials helped the management decide whether to continue extracting using mechanical methods or to introduce drill and blast methods to extract the rock."

Jan 1, 2017

By Robert Hopler

HUDSON MAXIM A Noted Inventor of High Explosives ALTHOUGH the subject of the present sketch has been a tireless worker in many fields of activity, his name is best known in connection with his work in the development of high explosives and their application to modern ordnance

Jan 1, 2012

By R L. Mayville

The author explains why the strategic location and important limestone reserves at Chattanooga Quarry led to a decision to extend operating life by continued benching down to lower levels. He discusses the steps taken to accomplish this objective. These include relocation of the primary crusher from the second level to the fourth level, pre-testing of explosives designs and powder factors, control of a substantial water problem, and computer monitoring of stone production costs.

Jan 1, 1984

By Sam Taoum, Omar Riahi

Few tools allow for accurately tracking ore dilution after blasting. Existing methods often rely on data analysis or linear interpolation of velocity, which can be imprecise and less effective in varied geological settings. A promising alternative is the use of numerical simulations, which involve complex mathematical calculations incorporating real physical data about explosives and geological characteristics. These simulations can model blast-induced fragmentation and subsequent ore dilution with greater accuracy, providing detailed insights into blast dynamics by considering factors such as explosive type, blast pattern, and rock properties. Numerical simulations integrate data from sources like seismic sensors, blast monitoring equipment, and geological surveys, offering a holistic view that single-method approaches cannot match. By simulating different scenarios, mines can predict the outcomes of various blasting strategies, optimize blast designs to minimize ore dilution, and maximize recovery. Advanced numerical simulations enhance the prediction of fragmentation distribution and size post-blast, crucial for effective dilution control and maximizing ore recovery rates.

Jan 21, 2025

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