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By Robert Morgan

With improved methods for designing and detonating shots the potential for flyrock can be significantly decreased, but there are few absolutes in blasting; therefore blasters must learn from the mistakes of others. Blasters must conscientiously employ control measures to minimize the risk of flyrock. The worst case incidents which tend to be widely reported by the media, should serve as a reminder to us all that minimizing the risk of flyrock must be incorporated into the design of the drill pattern and blast design.

Jan 1, 2001

By Robert McClure, Carlton Lehman

Rendering safe explosives in an urban environment presents a unique challenge due to the safety concerns and disruption to the general public. Potential damage to the surrounding homes, businesses, utilities and transportation infrastructure are some of the major concerns when planning the render-safe operation. Engineering controls to mitigate blast effects, such as damaging air over pressure levels, material ejection and ground borne vibration, need to be implemented as part of the operation. Monitoring of seismic and air overpressure during these operations are needed to protect against potential claims when controlled or unplanned detonations occur. Two recent render-safe operations conducted in and around urban environments dealt with deteriorated, sensitive dynamite and damaged blasting caps. Utilizing innovative neutralization chemicals and processes to render-safe the deteriorated dynamite, while protecting the general public, proved to be the safest, most environmentally responsible and cost-effective way to approach the problem. In both cases, the explosives, old dynamite and detonators were found in abandoned, unlocked magazines. The dynamite was in a significantly deteriorated state, which was evident due to the nitroglycerine found leaking in,around and under the dynamite cartridges. Iron wire permissible electric blasting caps were also found in a corroded condition with exposed explosives and un-shunted lead wires. With occupied buildings within 180 feet (54.86 meters) of the magazines, any procedure (e.g. transporting, countercharging, burning) that could potentially cause a detonation was not an option. In the event of an unplanned detonation during neutralization operations, several blast mitigation methods were employed to safeguard the site. This operation and a similar one with over 1,000 pounds of crushed and buried leaky dynamite were unique since all the explosives were rendered-safe and neutralized on site. The use of advanced neutralization products and filtering processes allowed for a safer, more environmentally responsible way to resolve the problem. The magazines and all residual solids and fluids were tested and confirmed by independent labs to have no explosives residues. The effluents were treated on site, tested and met safe levels, so they were disposed of at a local municipal wastewater facility.

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Mehmet Aksoy, Kagan Ozdemire

With increasing environmental constraints on the levels of disturbance induced by blasting operations upon nearby residents, there is an increasing need to be able to design cautious blasting with greater precision. Therefore, determination of maximum amount of explosive per delay for a certain distance especially in large blasts is of great importance for the elimination of these environmental problems. Although too many research studies had been carried out in the past in order to eliminate environmental issues produced from blasting unfortunately a general approach or formula has not been established yet because of the complexity of the matter. In addition to the wave and ground motion characteristics, the complexity of blasting parameters and site factors restrict the developing a general criterion. So experimental site-specific studies should be still done in order to predict and control blasting effects. This paper presents the results of ground vibration measurements carried out in Espey Open-Pit Boron (Colemanite) Mine located on the west side of the central Anatolia near Kütahya province in Turkey. Within the scope of this study, ground vibration components were measured for 13 shots during bench blast optimisation studies in order to predict peak particle velocity level for this site. In blasting operations; ANFO and Powergel Magnum 600 (blasting agent), Powergel Magnum (priming) and delay electric detonators (firing) were used as explosives. Parameters of scaled distance (charge quantity per delay and the distance between the source and the station) were recorded carefully and the ground vibration components were measured for all blast events using 4 different types vibration monitors (3 White Mini-Seis and 1 Instantel Minimate Plus Models). Then, the data pairs of scaled distance and particle velocity obtained from the 38 record events were analysed statistically. At the end of statistical evaluation of the data pairs, an empirical relation which gives average line at 95% confidence level and upper bound 95% prediction line with a reasonable correlation coefficient was established between peak particle velocity and scaled distance.

Jan 1, 2005

By David Miller, James Santoro

Blasting is often required in urbanized areas to allow for economical execution of construction, demolition, and mining. Several examples of operations that require blasting in built up areas include: rock blasting for foundation and utility excavations; surface and underground mining for mineral extraction; and explosives demolition. Although explosives demolition is an engineering discipline, not at all like rock blasting, it still uses explosives for the felling of structures that have outlived their usefulness. Through the use of modem technology and implementation of extra safety precautions, explosives are used safely in congested areas to make the performance of critical work economical and feasible. This paper discusses several precautions required when undertaking various types of rock blasting and explosives demolition in congested areas. It also presents the adverse effects that must be considered when blasting in congested areas. The effects identified include flyrock, vibration and airblast, fumes, and non-elastic (permanent) ground deformations/overbreak. Measures for mitigating and controlling these adverse effects to provide on-site and public safety are presented.

Jan 1, 2000

By Khushaal Popli, Vanessa Roeland, Brian Hall, Carl Diederichs

Highland Valley Copper (HVC) has embraced an integrated Mine to Mill approach to comminution since the late 1990s. Previous blasting optimization was carried out through adjustments to blast pattern geometry (i.e., reduction of burden and spacing). This approach proved very effective and HVC reduced the burden and spacing of high energy ore blast patterns to what was considered the practical limit that still allowed for efficient drilling and bulk truck loading operations. While mining in the bottom of the Valley pit near the end of the previous pushback, HVC encountered high static groundwater conditions which enabled the transmission of elevated inter-blasthole pressures that had the potential to exceed safe operating limits for initiation products. This risk was mitigated through an expansion of burden and spacing for the high energy ore patterns, reducing the application of blasting energy and increasing the average particle size in Mill feed.

Feb 6, 2023

By Dale S. Preece

A new three dimensional (3D) mechanistic model of fragmentation, called the Fracture Density Model (FDM) is used to simulate full-scale bench blasts at the Bararp dimensional stone quarry in Sweden. The model uses several computational mechanics algorithms to simulate the effect of blasting in different rock types

Feb 1, 2020

By Agus Sasmito, Akash Adhikari, Srivatsan Jayaraman Sridharan, Purushotham Tukkaraja

Previous studies on blast fumes(CO + NO2) clearance and workplace re-entry time have overlooked the effects of toxic gases entrapped in the muckpile. The currently available models forcalculatingthe mine re-entry times assume that all post-blast fumes are emitted upon detonation. However,recentstudies reportedthat as much as 60% to 70% of the fumes or gases produced during an underground development blasting couldremain entrapped in the adjacent rock mass or in the muckpile. Entrapped fumes are slowly released,and when disturbed, high concentrations are released, representing a possible risk during the digging and transportation of the muckpile. This study uses CFD, SC-Flow software to understandthe behaviorof the entrapped fumes and theireffect on mine re-entry time.

Feb 1, 2020

By Reynold N. Hoover

The bombing of the Murrah Federal Building in Oklahoma City, Oklahoma, on April 19, 1995, has once again renewed public debate surrounding the availability and use of explosives in the United States. In the past, Congressional review of explosives regulation has generally followed tragic events such as the bombing of Pan American World Airways Flight 103 over Lockerbie, Scotland on December 21, 1988; the February 26, 1993, bombing of the World Trade Center in New York City; and the delivery of six package bombs to members of one family in several western New York communities, killing five people, on December 23, 1993.

Jan 1, 1996

By M. Araos

Non-ideal explosives can be characterised by different methods like velocity of detonation measurement, double pipe tests, underwater tests, aquarium tests, etc., to name a few. Both aquarium and velocity of detonation tests were selected to characterise a non-ideal explosive that is based on hydrogen peroxide, fuel, and void sensitisation. The detonation process in an aquarium of this sensitised explosive was captured at 80,000 frames per second using a high-speed camera. The explosive product was detonated using 51mm (2inches) diameter acrylic pipe charges. The product was detonated at different densities in an aquarium (cube box containing water). An aquarium provides a homogenous confinement for the detonation of explosives and more importantly, allows observing the shock wave as it changes the refraction index of water. The analysis of the video footage allowed the calculation of the velocity of detonation, pressure, gas rate release, and how the shock wave's shape in water changes with densities. It is suggested that the calculation of the rate of gas release could be related to the bubble data obtained from underwater tests.

Jan 1, 2024

By E. Lentilucci, A. Dey, X. Liu, A. Datta, S. Ghosh

The segmentation of quarry blast smoke plumes is a crucial research area that has the potential to enhance safety, environmental monitoring, object detection, and regulatory compliance in the mining industry. Smoke plume segmentation can be used to identify the spatial extent and temporal evolution of smoke plumes generated by the blast. This information can be used to improve the understanding of blast dynamics and optimize blast designs. Furthermore, smoke plume segmentation can assist in identifying potential environmental and health hazards associated with the release of smoke and dust particles into the atmosphere during quarry blasts. However, many current smoke plume segmentation algorithms are designed for segmentation of smoke plumes from fires and are not suitable for segmentation of plumes from quarry blasts. The proposed method in this paper leverages the video frame captured before the blast as a stationary background image, which helps to reduce other confuser objects present in the image along with a selfadaptive clustering method. The color channels of the image are utilized based on the different contrast properties of the smoke, with a self-adaptive gradient compensation applied for edge detection of the smoke plume. This approach offers a novel and effective way to segment smoke in quarry blast analysis, with potential applications in the calculation of noxious gas volume and concentration within the plume. Compared to other algorithms, our method improves accuracy, decreases the false alarm rates, and reduces the overall miss rate. Overall, this paper contributes to the research on smoke plume image segmentation, particularly for quarry blast smoke plumes, which possess unique characteristics that require specialized algorithms for accurate segmentation.

Jan 1, 2024

By Dale S. Preece, Lee M. Taylor

Accurate computer prediction of the muck pile produced by a conventional blast requires modeling of the physics that occurs during the rock motion phase of a blast. The ability to predict the motion and the subsequent muck pile can have a significant economic impact on the mining industry.

Jan 1, 1990

By Robert B. Hopler

Emplacing explosives in the borehole by bulk methods is utilized today for about 35% of all of the explosives used in the United States. Although different from today's methods, some bulk emplacement has been utilized throughout the history of explosives. This paper provides an overview of the evolution of the industry from primarily packaged to primarily bulk materials and methods.

Jan 1, 1992

By Ajoy Singh

A study was conducted to investigate the damage potential to underground multi-seam openings caused due to vibration generated by open-pit coal mine blasting. The objective was to recommend optimal explosives weight per delay to be detonated in open-pit blasts to ensure the safety and stability of underground openings. Sixteen blasts with varying charge weights and initiation sequences were conducted at Samleshawari open-pit mine and eighty four blast vibration data were recorded in the Hingir Rampur underground colliery in India. Analysis of vibration data showed that roof of the underground openings vibrated with higher amplitude of vibration compared to pillars and floors. The amplifications of vibration in the roof at the junction were upto 4.3 times the pillar vibration. It was observed that coal chips detached from roof when the peak particle velocity reached 131 mm/s or high. The vibration magnitude recorded was higher in upper seams openings than in below seam openings. Rapid attenuation of vibration was recorded in below-seam openings at similar locations. Appropriate particle-charge weight-distance equations were established to calculate the safe explosive weight per delay to be detonated in open-pit mine for safety of multi-seams workings of underground mine. The support for the galleries and junctions were further modified for the working seams to ensure greater safety.erground Coal Mine

Jan 1, 2012

By Angelina Anani, Seffit Aderuyi, Sylvester Avane, Joseph Wilson-Sey, Amatus Niminye

The Edikan mine in Ayamfuri, Ghana, faces economic challenges and community resistance due to its proximity to residential areas, particularly concerning blasting operations. Controlled blasting trials using air deck applications were conducted to address community concerns by minimizing environmental impacts and explosive costs. This method involves utilizing an air gap within blast holes to prolong the action of shock waves on the rock mass, enhancing crack formation and reducing rock movement. The trial project at the Edikan open pit gold mine aimed to evaluate the effectiveness of air deck blasting in reducing ground vibrations and overpressures, and to assess its impact on blast performance and economics in the prevailing geological conditions of meta-sediment and hard granite rocks. Results indicated lower Peak Particle Velocity (PPV) and Peak Sound Pressure Levels (PSPL) values in the air-decked blasts. Additionally, more uniform rock fragmentation and enhanced blast economics were achieved. Explosive costs were reduced by 20–24%, saving $0.97 to $2.24 per hole depending on the rock type. Overall blasting costs per volume decreased to $0.54 in granite and $0.48 in meta-sediment compared to conventional methods.

Jan 21, 2025

By T. G. Sitharam, P. B. Choudhury

Prediction of ground vibration (peak particle velocity, PPV) and frequency is an important task in geoscience. Till date, many empirical equations are derived from conducting trial blasts in the mines, to arrive at attenuation predictors. These predictors are usually site dependant and hold good for one particular type of rock/strata. These predictors cannot be used for geologically different rocks/strata. This paper presents the application of support vector machine (SVM) model, for predicting blast induced ground vibration and frequency, using a one comprehensive model for three different types of rock. Inputs to the SVM model formulation involve twenty one parameters consisting of geotechnical properties of the rock mass, blast design geometry and explosive properties, and the output of the formulated model is peak particle velocity and its associated frequency. The data has been acquired from eight limestone mine, five coal mine and two manganese mines. The comprehensive SVM model is formulated using 400 datasets and tested with 143 datasets. The performance indicators to the model not only justify its formulation but also the advantages it has over site specific predictor models. The SVM model not only predicts PPV, with higher correlation coefficients as compared to predictor equations, but also the associated frequency.

Jan 1, 2010

By D. S. Preece, S. Silling, A. Bhuiyan, C. M. Lownds

GEM (Geologic Element Motion) is a Discrete Element Method (DEM) capability for blast-induced heave simulation with a very fast computational algorithm that can efficiently treat many different element shapes by utilizing alternating arcs and lines. GEM calculates rock motion from a knowledge of the gas pressure moving the elements. This requires an expression for the pressure vs volume, or the adiabat, of the explosion product gases. This work uses an analytical expression for the adiabat derived from the explosive’s properties. The effect of the explosive detonation pressure in crushing an annulus of rock, and setting up a shock wave, is termed Brisance. GEM incorporates a working hypothesis for the deleterious effect of Brisance on subsequent rock motion.

Jan 1, 2024

By Stephen G. Rieben

Almost everyone has at least heard of the two one-call systems which serve New England. They are "Call Before You Dig", which covers Connecticut, and "Dig Safe", which covers the remaining five New England states. Those of you who are more familiar with these programs know that it is our job to help guard against the accidental dig-ups of buried plant and to prevent facility service disruptions. We cover all types of buried facilities, from cable television to high pressure gas transmissions lines, telephone cables, electric facilities, fiber optics and everything in between

Jan 1, 1990

By Tony Rorke, Sydney Thabethe

A large overburden blast was carried out at Douglas Colliery, Middelburg Mine Services, close to a national road in South Africa. The road is a busy route between Witbank and Bethal and damage to the road could not be risked. The section of road next to the blast was particularly prone to damage, because it had been mined out on its eastern flank, and the large blast was to take place on its western flank. There were thus three potential damage risks: 1. Fly rock damage to the road surface 2. Vibration damage to the road substrate 3. Damage caused by bulk displacement of the block supporting the road into the void on the mined out side. This paper presents the design and blasting methods used to control the blast and avoid these three risks. Electronic delay detonators were used in multi-decked holes. Signature data were used to determine the blast timing to make sure that delays were used that would provide destructive interference. The timing direction and sequence was decided using wave interference patterns to direct repeated shocks away from the road. The precise detonators and the odelling capability allowed effective control of the blast vibration result. Each hole was charged with two explosive decks separated by a deck of aggregate to limit the charge mass fired per delay and thus limit the reaction forces acting towards the unsupported road. The vibration and blast results are presented in the paper, together with the design that was applied. Details are provided on how the blast was charged and primed. The detonators that were used are described and the timing design is presented.Copyright © 2004 International Society of Explosives Engineers 2004G Volume 1 - Blasting Next to an Unsupported Road Using Electronic Detonators 1 of 13 It is concluded that damage risk to nearby structures can be effectively controlled using electronic delay detonators, provided the appropriate modelling is applied to obtain the most effective delay periods.

Jan 1, 2004

By Mark Spaniel

Computer 3D modeling to evaluate the potential underground blasting fragmentation performance based on rock within calculated damage radii along drillholes, as well as the burden distance from explosives along each drillhole. The results estimated from the 3D computer models closely predicted results found in the real world testing.

Feb 1, 2020

By Anders Lagerkvist, Agne Rustan, Tommy Edeskar

Landfills containing house hold waste produces methane gas during its decomposition. This gas can be recovered and used for heating purposes or as fuel for vehicles. Gas drainage pipes are installed in the landfill and connected to a central suction point. Methane gas is produced over several years until the slots in the drainage pipes are clogged by black mud. And the bottom of the vertical drainage pipe are filled with mud and water. The hypothesis tested in this paper is if blasting in the drainage pipes could activate the production and flow of methane. In the first part of the paper we have studied what maximum linear charge concentration could be used in different size of PE-pipes place vertical on surface and surrounded by air. The results show that the maximum linear charge concentration for single blasts varied between 5-10 g/m, depending on the diameter of the pipe (90, 100 and 160 mm). Maximum charge concentration for the repeated blast varied between 2-5 g/m. In the second part of the paper we study what maximum linear charge concentration could be used in situ for full scale blasting tests in a special prepared test area which later on was dug out after the blastings. Up to 40 g/m could be used without damaging the top of the 160 mm diameter pipes. The increase in methane flow was so low so it could not be measured c4.5 m3/h. The conclusion therefore is that the stimulation of methane flow by explosives is not enough.

Jan 1, 2000