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By Ambrose Buchanan, Rob Farnfield, Charles Adcock

Beginning on 7th September 1940 the City of London was subjected to 57 consecutive days of bombing in what became known as the ‘London Blitz’. To commemorate the 70th anniversary of this event a television series was commissioned that required the open detonation of World War 2 equivalent bombs close to purpose built structures constructed using period design and materials. The structures were built on a remote test facility in the North of England that is able to fire large quantities of explosive in the air.

Jan 1, 2011

By Alain Blanchier, Anne Charline Sauvage

Rock mass variations have a huge influence on explosives efficiency and on blasting results. Numerous blasting improvements could be gained by taking into account rock mass and its variations. However, extracted rock mass is generally considered as statistically homogenous. The development of a panel of pre-blast survey procedures that every blaster can use, consists in the realization of a process integrated into every day work: for example as well as toe burden or blast hole depth, discontinuities spacing or the weathering expanse have to enter in rule book, if it provides blasting efficiency and security improvements.

Jan 1, 2004

By Les Willan, Chris Batten, Matt Sparkes

In late 2008 Xstrata Newlands Coal Mine in Central Queensland and Orica Mining Services engaged in discussion to investigate methodologies to change their current mining practices and overcome the issues in the mining of steeply dipping coal seams, the associated coal loss risk and to assist in improving mining productivity. A strategy was developed and it was determined that through-seam blasting was essential to the success of winning the coal from the Wollombi Pit at Newlands.

Jan 1, 2010

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 Darío Innamorati, Jorge Oliva

Cerro Vanguardia is a known gold and silver deposit located in the province of Santa Cruz, Argentina. The mine has been in operation since 1998 and is thought to be one of the most important mines in Patagonia. More than 102 epithermal quartz veins have been identified in the area, with variable lengths, thicknesses, orientations and dips that constitute what is possibly one of the most extensive outcropping vein systems on earth. Veins are vertical and have variable depth. For this reason, the deposit is currently mined with a variety of extraction methods. This operation is made up of more than 60 open pits and 20 underground access ramps to exploit the deepest high grade narrow veins. This study is focused on the combination of underground exploitation with open pit blasting. That is, those production stopes in the upper levels of underground mines and their interaction with the damage levels in the final slope of open pit mines, as well as in the study of the impact of the generation of vibrations from the blasting of open pit mines and their influence on underground mines. Considering the current stage of the mine, after 20 years of operation, Cerro Vanguardia faces the need to mine deeper deposits in the face of increasing costs and declining grades. For this reason, it is essential to study the interaction of these exploitations. From a personnel safety point of view, this interaction must be well coordinated so as not to affect people and equipment. Likewise, the generation of vibrations due to blasting must be studied, which would produce new cracks, potentially generating overbreak and dilution. The main objective of this study is to determine the possible causes and influences of the blasting interaction in open pit and underground mines, seeking an optimization of the blasting process and a safety standard for personnel and equipment. To achieve these goals, this study includes a vibration monitoring plan to analyze the charge performance and determine rock constants. With the use of specialized software, damage modelling and simulations are used to determine values of damage in order to reduce overbreak. In addition, this plan contemplates the estimation of flyrock in blasting where underground work is connected to the surface, determining safety distances when carrying out a blast.

Jan 21, 2025

By Norm Disley, Kingsley Hortin, Gertjan Bekkers

As part of the expansion of the Kidd Creek Mine to 2,682 meters (8800 feet) below surface, two largediameter 3000kW (4000HP) booster fans were installed at the 6000 level. Shortly after commissioning the fans, significant damage to the fan bearings were observed, forcing several shutdowns for repairs, which were very disruptive to the mine’s production process.

Jan 1, 2008

By Damien Bretall, William Fourney

Due to the changing face of warfare there is an ever growing need to protect the underside of combat vehicles from mine blasts. This paper presents a new method to better characterize the pressure profiles experienced by a plate as the blast develops. The explosive deformation of a small-scale plate was recorded using synchronized high-speed digital cameras, and then analyzed using 3D Digital Image Correlation software. Time-varying pressure profiles were input into an axisymmetric FEM simulation by fitting curves to data obtained from tests using Kolsky bars to measure pressures. These were then modified to find possible profiles that produce the measured deformations. It was discovered that the final deformation cannot be determined from only total impulse or peak pressures, and that it is very sensitive to the time and spatial decay of the pressures.

Jan 1, 2009

By Randy Wheeler

In recent years the issue of seismograph calibration and accuracy has been a major focal point of the ISEE Blast Vibration and Seismograph Section. In fact, questions concerning the consistency and reliability of seismograph measurements essentially led to the development of this ISEE section. One of the early actions of the section involved the development of “Field Practice Guidelines” for the use of seismographs. These guidelines specifically state that “Placement and coupling of the vibration sensor are the two most important factors to ensure accurate ground vibration recordings.” This paper will address the results obtained from using different coupling methods to record vibration and airblast levels generated from production blasting in a limestone quarry. The data obtained clearly indicate that seismometer burial provides the best coupling for recording ground vibrations. Microphone height has also been an issue regarding the accuracy of recorded airblast levels. The data we obtained indicates that microphone height is not a significant factor.

Jan 1, 2004

By María Rocha, Benjamín Cebrián, Roberto Laredo

"Ring blasting designs have to achieve different goals in order to become efficient whether is done in up hole or downhole fashion. Ore recovery/dilution control, fragmentation and drift integrity all have to be taken into account when selecting parameters such as burden, spacing, linear explosive density and stemming. Blast energy simulation allows identifying contours of rock breakage and fragmentation, thuschoosing a combination of spacing at the end of holes and appropriate burden. Also, simulations are keyto concentrate energy levels on the mid part of the ring while making sure there is not too high of energy concentration around the drift, which integrity is needed for a safe ore mucking."

Jan 1, 2017

By Alastair Torrance, Italo Onederra, Do Sun Kim, Kush Patel, Gary Cavanough

Reactivity of ammonium nitrate-based explosives is associated with the presence of sulphide in the ground reacting with explosive products and in some instances causing spontaneous reactions which can lead to detonation. This paper explains the mechanism of these reactions, the potential cause of spontaneous detonation and how inhibited explosives prevent the reaction

Jan 1, 2019

By Zong-Xian Zhang

In sublevel caving mines, serious eyebrow break usually gives rise to lower ore recovery, higher dilution, and worse safety for the people working in the field. For example, chargers must go near the caving region and stand under the damaged eyebrow where a hanging stone may suddenly fall down or rock fragments may quickly roll down.

Jan 1, 2011

By BruneJurgen F., Richard C. Gilmore, Matthew Schreiner, Ray Johnson

Explosive pockets of methane-air mixtures accumulate in underground coal mines and, when ignited, produce an air-blast wave that can disturb combustible coal dust on the floor, roof, and ribs. To prevent explosions, the coal dust must be continuously diluted through application of inert rock dust, usually powdered limestone. Application of powdered dust process creates a respiratory nuisance downwind, where miners cannot work until the dust settles. Rock dust suppliers have developed wet and foam applied products to reduce the nuisance and limit the interruption to mining during dust application. To test the effectiveness of these alternative dust products, researchers at the Colorado School of Mines (Mines) have constructed a full-scale explosion test drift located at the Mines Edgar Experimental Mine (Edgar) to study the dispersibility of different rock dust applications. This paper examines the use of Pentaerythritol tetranitrate (PETN) detonating cord to produce controlled air-blasts that simulate methane-air explosions. The air blasts are generated with curtains of detonating cord that produce shockwaves with wind speeds between 30 to 70 m/s (100 to 225 fps) depending on the length of 5.3 g/m (25 grain/ft) detonating cord used. These velocities represent the minimum air speeds required to trigger propagating coal dust explosions. Researchers have conducted 40 test blasts with various lengths of detonating cord. Results show the two primary waves and two reflected waves each decaying into airblast waves with overpressures of 14 to 27 kPa (2 to 4 psi). Pressures were recorded with commercial piezoelectric transducers and custom-built, bi-directional probes to record the total and dynamic pressures of the wind generated in the explosion. Researchers were able to generate consistent and repeatable wind speeds and air-blast durations sufficiently similar to a methane-air explosion to study the dispersibility of various rock dust products and application methods

Jan 1, 2019

By Catherine T. Aimone-Martin, Kristen Kolden

In August of 2013 the USDA Forest Service (USFS) blasted bedrock at the base of a waterfall in Kanalku Creek within the Kootznoowoo Wilderness Area on Admiralty Island in the Tongass National Forest located in Southeast Alaska. The purpose of the blasting was to widen and deepen a plunge pool at the base of a waterfall complex considered to be a partial barrier to migrating sockeye salmon. Drilling and blasting to remove 12 to 15 cubic yards of rock occurred over a two day period.

Jan 1, 2015

By G. Adderley, Rob. Farnfield, L. Bermingham

The benefits of using electronic detonators within the drilling and blasting process in both surface and underground mining operations are well established and the use of this technology is widespread in the minerals industry. However, many users of such devices will also have experienced misfires where an electronic detonator has malfunctioned and shows evidence of damage from either transient shock or gas pressure. This is typically exhibited as a detonator shell that has collapsed causing damage to the internal electronic components before the detonator has initiated. Users often describe such detonators as being “shrink-wrapped”. The excavation of a misfire is always a hazardous operation, and it is better to minimize the risk of one happening in the first place. As part of a programme to improve understanding of this phenomenon and to allow a comparison between differing designs of detonators, a simple practical test was developed. This process involves the firing of a booster near electronic detonators in water. This paper describes this test work and draws some tentative conclusions on pressures for onset of damage with detonator shells made from different materials. The investigation has also yielded data showing that for some designs there is little difference between the pressure resulting in complete malfunction and sympathetic detonation

Jan 1, 2024

By Charles R. Barnhart

The Nitrogen Dioxide Cloud: After one year of testing it can be stated that we do know and understand a great deal about why the nitrogen dioxide formation is exacerbated in cast blasting. Picture 1 is an example of how concentrated the NOx can be from a cast blast. It has long been felt that 300 or more milliseconds of timing needs to be put between each row of detonations to allow the rock a maximum time of flight so the cast percentage is high. Our experiments have found that higher cast percentages can make with timing between 150 to 200 milliseconds between rows. Picture 2 show a definite improvement in nitrogen dioxide concentration and most of that was the result of shooting a previously shot end of the cast pattern that had not been dug, thus no confinement of the powder columns.

Jan 1, 2004

By Andrew Palangio, Blessing Taiwo

Understanding rock mass structural features is essential for optimizing blast design, highwall control, and evaluating post-blast performance in both surface and underground mining operations. This paper presents a comprehensive methodology utilizing image-based structural mapping to accurately characterize geological discontinuities including joints, faults, and lineations captured from both terrestrial and aerial imagery at varying scales. Key structural parameters such as joint orientation, spacing, and apparent in-situ block size are extracted to understand rock mass classification and enhance blast design inputs with greater geotechnical precision. The study introduces a significant enhancement to the existing discontinuity assessment algorithm by integrating a deep learning-assisted detection process. This improvement enables more accurate, quantitative and consistent identification of pre-existing cracks and surface features across complex bench free faces. The enhanced system facilitates better evaluation of how structural features influence blast fragmentation, energy distribution, and slope stability. A case study from a limestone quarry illustrates the use of a derived comminution factor based on the relationship between joint-controlled pre-blast block sizes and post-blast fragmentation to evaluate blast performance and optimize future design strategies. The results highlight the value of structural analysis in reducing overbreak, minimizing underbreak, and improving fragmentation predictability. This paper emphasizes the importance of integrating structural assessments into the blasting workflow to enable a more data-driven, geotechnically informed, and performance-optimized approach to modern blast design and evaluation.

Jan 26, 2026

By Cesar Guerra, Alejandro Rojas, Dr. Jhon Silva, Luis Velasquez

The ANN method is applied to predict the P_80 size in one open pit gold mine in Peru. The ANN was implemented in Matlab programming language, and the results from the ANN are compared with data obtained using photo-fragmentation analysis software.

Feb 1, 2020

By Barbara Rutter, Shonn Kevin McNeil

"This study discusses how a prototype was built to measure the sonic velocity in powdered explosives.The sonic velocity of an explosive is a benchmark to determine if the explosive deflagrates or detonates;however, little work has been done to determine this value for powdered explosives. This paperdiscusses the results of the initial prototyping tests where two known mediums, air and water, were used for validation. The prototype did record the sonic velocity within the known velocity ranges of air and water; however, a few depths did not fall into this range. This prototype could be used for testinggranular materials."

Jan 1, 2017

By Tyler Acorn, Paul Worsey, Nathan Rouse

The effect of the hole diameter on vibration attenuation has not been incorporated in most vibration models in the blasting industry. In current vibration models, the charge weight and the distance from the blast are the two primary variables that are addressed. Charge weight is a function of explosive density, charge length, and charge diameter. This geometry-weight can complicate the isolation of the charge diameter variable.

Jan 1, 2013

By P McConnell, T Garrigan

Tara Mines Limited, in Ireland, is Western Europe's largest zinc mine. Annual metal production, from 2.5 million tonnes of ore, consists of 180,000 tonnes of zinc and 34,000 tonnes of lead.

Jan 1, 1989