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By Scott G. Giltner, Alex Schwenk

This paper is an update on a paper presented at the 2022 ISEE conference. The original paper presented how the mine operator desired to open up ore reserves near several mine structures including two crushers, the conveyor belt drive and the concentrator thickeners. In order to open up additional ore for extraction (over 3 million long tons or 3 million tonnes) it was necessary to blast out two benches near the mine structures. Since the two benches have been successfully shot, the mine has now conducted nine production blasts in this area at distances as close as 116 m (380 ft) to the two primary crushers. These production blasts are full size production blasts consisting of up to 300 or more blast holes. For these blasts the two primary crushers were still the critical structures as they were the production life blood of the mine. If the crushers were shut down due to any damage from the blasting, the revenue of the mine would be adversely affected. As with the initial bench blasts, two issues provided an extra challenge to the blast design. The first was that the blast holes were still considered large diameter at 12¼ inches (311 mm) and 16 inches (406 mm). The second issue was that the bench heights were short, with the average varying from 34-40 ft (10.3-12.2 m). This combination of large diameter blast holes with a short bench provided an unfavorable geometry for the goals established by the mine management. The mine management established the following goals. 1) None of the mine structures would be damaged by fly-rock. 2) Minimize the blast vibrations at the crushers. 3) The last goal was to produce a muck pile that could be dug easily by hydraulic shovels. Electronic detonators were applied to achieve the necessary control of the blast and optimal fragmentation throughout the mine. UAV surveys of the blast area were also conducted to provide a 3-D representation of the free faces and bench surface. The 3-D point cloud produced from this was used to measure the shape of the free faces. Once the shape of the free faces was quantified, it was possible to establish proper placement of the crest holes and develop a custom explosive load for each blast hole. The results of the nine blasts have provided what the customer requested. The peak vibration level at the crushers for the nine production blasts was 1.6 in/s (40.6 mm/s) at a frequency of 18.9 Hz. There have been no fly-rock or blast vibration issues at any of the nearby mine structures. As a result, the mine has been able to maintain its production with no downtime. The muck piles have been well fragmented with reports from the shovel that they have all dug well.

Jan 21, 2025

By Mohammed Alkazimi, Katie Grantham

The purpose of this paper is to quantify the risk to both the environment and surrounding infrastructure from a pipe sealing implosion. Both accuracy and the precision in determining how a submerged infrastructure damaged by underwater explosions performs provide better decision-making capabilities for managers facing impending oil spills. This determination is vital, especially for both emergency and crisis management teams, as categorized consequences based on both the nature of the structural layout and the surrounding marine environment assist in identifying whether or not the utilization of this technique is applicable. Thus, the decision maker’s aim, in a crisis, is to minimize any associated risk that might result in aggravating the situation by endangering both the infrastructure and marine life. Therefore, the resulting risk matrices will enable technical personnel who are not experts in explosive technologies to be armed with the information necessary to determine if this mitigation technique is applicable to their situation.

Jan 1, 2013

By Karl Christopherson, Vanessa de Viterbo

Trim blasting is an integral part of the mining processes at the Morenci Mine, a Freeport-McMoRan Copper & Gold Inc. property. Trim blasting near high-walls or Finals blasting requires a tighter distribution of energy but a reduction in total energy factor near the wall. Recent Finals blasting in Morenci Mine was allowing the shovel to dig to the final design limit, but causing high-wall instability due to excessive energy or production of energy (blast design and timing). Slope instability events reduced production in two of the three operating pits in Morenci over 2009. In order to avoid high-wall instability from Finals blasting, a new method was required. The new method utilizes air-decks, unconventional row timing, and blast design based on the geology predicted. Many different geologic structures and rock types exist in Morenci, and different strategies were needed for the many predicted geologies. Drill penetration rate and core mapping were the primary tools for determining the blast design. Patterns were designed within a consistent geology; with weaker rock types receiving a lighter load than the stronger rock types. Penetration rate returned by the drill would be the determining factor on the actual rock hardness. Maintaining the pattern geometry on Finals designs should not be an issue as long as the lb/hole is adjusted to reduce powder factor close to the high-wall. One requirement of Finals blasting should be that the powder factor matches the geology as closely as possible. A softer, fractured zone should use approximately one-half to two-thirds the explosive charge of a competent, sound geological zone. This has been incorporated into the final Trim blast design. It is impossible to protect every high-wall from close-in blasting, especially those with crossing prominent joint sets inclined toward wedge failure, but this new design has provided protection on walls where the mine was encountering problems.

Jan 1, 2011

By R. Raghavaraju

Estimation of the dynamic stress field in terms of its amplitude and decay around a blast hole is a key input parameter in all numerical modeling and blast prediction exercises. However, there is very limited information available in literature on these critical parameters, which would be considered essential in any blast modeling exercise. A laboratory-scale experimental study has been carried out in two different rock types to study at very close range the stress wave decay from a blast hole at distances ranging from 3 to 10 borehole radii. The single–hole blasting experiments employed a centrally located detonating cord (5.3 g/m) in 6 mm(1/4 inch) and 10 mm (3/8 inch) boreholes. The coupling medium employed was air and water, in addition to using a thin-walled copper tube in intimate contact with borehole wall to prevent of penetration of explosion gases into the emerging cracks. The paper describes the nature (amplitude and decay) of the transmitted shock pressure and their evolution in the two rock types for these various experimental conditions, which are present to varying degrees in all blasting operations.

Jan 1, 2014

By Harry L. Siebert

Pre-splitting was substituted for line drilling to achieve stable rock slopes and reduce excavation beyond the pay line on a Connecticut highway project in 1962-63. Changes have occurred in developing rock slopes that were not foreseen by Alan Bauer and Jim Scott who in the early days understood the relationship of explosive energy to stable slopes. Cushion blasting as currently used produces slopes designed to blend or complement the natural landscape with slope holes detonated after the main body of holes. Pre-splitting is the opposite. The best results have been achieved by detonating the pre-split line of the holes first to allow readjustment of the slope plane fracture and a separate blast for the main body of loaded holes.

Jan 1, 1998

By Dale Preece, Joergen Pilz, Zavis Zavodni

An overland conveyor was constructed at a surface coal mine to reduce the truck haul distance and make the operation more efficient. An important element in this system is a truck dump facility to transfer coal from truck to conveyor. Mechanically stabilized earth retaining walls were employed to accommodate the coal processing equipment, including the crusher, in this facility. These retaining walls are close enough to the pits being mined that blasting induced vibrations must be considered in analyses of the wall structural stability.

Jan 1, 2010

By Brian Warner, Siavash Mahvelati, Douglas Rudenko, Mohamad Sharif

Predicting and optimizing production shot vibrations using time-shifting and superposition of signature hole waveforms (seed waves) has been widely used for many years. In this method, a single borehole is detonated and recorded with seismographs at the locations of concern. Since a single hole waveform is a reproducible event, it is reasonable that the seismic signature from a multi-hole production shot can be predicted by summing a series of single hole waveforms that have been time‐lagged at intervals corresponding to delay times from the production shot. However, there are instances where seed waveforms are collected at locations other than the exact location of concern, which raises questions regarding the applicability of such recordings. The present study adopts the well-known concept of dispersion of surface waves to predict seed waves at a location of interest based on seismograms recorded at a closer offset. Surface waves, as their name suggests, are seismic waves that propagate along the Earth's surface. They are the dominant wave type within one wavelength from the ground surface. Surface waves are dispersive in nature meaning that in a layered medium, wave components with different frequencies travel at different velocities causing an input signal to disperse as it propagates. The proposed technique takes seed waves recorded at one location as the input and passes it through a frequency-dependent function developed using site dispersion characteristics. The site’s dispersion characteristics are either measured directly with surface wave methods or retrieved using shear wave velocity information. The output of the function is the seed wave prediction at the farther location of concern. The theoretical background, including the underlying assumptions and limitations, is discussed in detail, and the application of the technique is illustrated through field data from two sites.

Jan 26, 2026

By Thierry Bernard, J. M. Laboz

2000 HIGH-TECH SEMINAR Blasting Technology, Instrumentation and Explosives Applications

Jan 1, 2000

By Martin Langenderfer, Catherine Johnson, Phillip Mulligan, Kelly Williams

The physical geometry of a charge has a direct correlation to the geometry of the shock wave. This relationship appears strongest within the boundaries of the visible fireball. As the shock wave propagates outward past the limits of the fireball, the theory states that the geometry of the shock wave should even out and become more spherical. This paper investigates pressure vs. time at two distances, one ‘Near Field’ at the extent of the fireball and one ‘Far Field.' The two Fields were instrumented with three free-Field pressure probes from PCB oriented at 0, 45, and 90 degrees to the front face of the charge, in the same horizontal plane as the charge. This orientation allows for the comparison of the shock wave from the face and vertices of the charge. All the pressure sensors were connected to a Data Acquisition System (DAS) recording at 2 million samples per second (2MS/s). Two high-speed cameras, a Phantom and an MREL Ranger II, recorded the detonations for qualitative examination of the fireball, and the shock wave. Three charge geometries were used and compared to the shock propagation of a sphere. The other geometries tested are cylinders, cubes, and tetrahedrons. Charges were made from a PETN based sheet explosive. In the Near Field, a lower pressure is observed along charge vertices with highest pressures from each face. In the Far Field, vertices record a higher pressure, possibly due to the shock waves from the adjacent faces intersecting, indicating that shock pressures do not always even out in the Far Field. This paper will describe the methodology and findings of this experiment and attempt to determine causality for trends in the data gathered.

Jan 1, 2018

By Edward Walter

Rock excavation for tunneling projects occurs on a regular basis in the Cleveland area. These tunnels are being constructed to increase the capacity of the sanitary sewer system. Controlled blasting must be performed to remove rock in a number of phases of the project. The rock excavation for construction of a junction chamber is just one case where blasting is the safest and most efficient method available.

Jan 1, 2001

By Michael Twomey, Alastair Torrance, Alan Twomey

Low density explosives have been available in various forms for nearly 20 years. These initially consisted of various diluted forms of ANFO formulated to slow the rate of reaction. One such product that was developed was a blend of ammonium nitrate and rubber. This product uses a coarse fuel provided by granulated rubber to slow the reaction rate of the explosive rather than being a diluted form of ANFO. There has always been a technical difficulty in blending two dissimilar materials without subsequent segregation.

Jan 1, 2011

By Radhe Krishna, Mutale William Chanda, Timothy Mwale

Blasting as a process is the emplacement of industrial explosives into blast holes suitably located to a free surface and detonated. Every blast hole containing a certain amount of explosive charge undergoes impulsive loading when detonated and results in the dynamic transfer of a powerful shock wave to the surrounding rock. It is the shock wave that brings about rock breakage when the tensile stress produced upon reflecting from the change in material density or free face overcomes that of rock material tensile strength. However, this shock wave comes along with unwanted destructive consequences such as damage to remaining rock, ground vibration, noise and fly rock. The above mentioned consequences pose a great threat to the Community of Wusakile, Kitwe as Mopani Copper Mines Plc wishes to increase its production by expanding the pit towards the community that lies within 150 m (164 yd) from the pit rim. As a requirement from the Zambia Environmental Management Agency (ZEMA), all blasting operations close to the community must maintain at least below the maximum vibration threshold of 10 mm/s (0.3937 in/s) PPV-Peak Particle Velocity or else risk closure of the mine (AMC,2009). In order to satisfy the above statement, a good understanding of explosives is required. This paper therefore presents the phenomenology of rock breakage by explosives with much emphasis on electronic blasting and how best this process can be controlled in densely populated communities. Factors affecting maximum projection distance such as, size of the fragment, shape of the fragment, angle of projection, the state of confinement of an explosive charge, were also studied. In addition, design faults, deviation in implementation and unforeseen geological conditions were also considered. The paper discusses the above facts based on research.

Jan 1, 2015

By Ethan Steward, Kyle Perry

Blast resistant structural design continues to be a research area of major concern for governments around the world due to explosive threats from both state and non-state actors. Glass and aluminum curtain wall systems are commonly used to clad the exterior of government and commercial structures, allowing light into the building, regulating the interior environment, and providing an aesthetically pleasing exterior. These systems are likely to fail when exposed to sudden, high-pressure events such as the purposeful or accidental detonation of explosives. Engineers have designed blast resistant curtain walls and structural elements to reduce the likelihood and severity of failure, but the design tools and testing mechanisms commonly used in the process may not accurately model or simulate actual blast conditions at all ranges. In blast resistant structural design, the origin of a shock wave is typically assumed to be in the far-field, creating a wave that is nearly planar and parallel to at least one face of the target. Shock is applied evenly and immediately across the entire impacted surface. However, the source of real-life blasts is often very close to the target structure, and the assumption of far-field planar shock does not always apply. Mid-field blasts exhibit qualities different from those assumed about far-field shocks, specifically a hemispherical shock that produces different peak pressures, impulse curves, oblique reflections, and Mach stems across a target. This paper will examine mid-field shock effects from scaled distances of 2.5 to 4 13 (6.3 to 10.1 13) on a tall, scaled target by measuring reflected and incident pressure, impulse, and shock velocity across the target. Results will be compared to theoretical blast parameter equations and empirical data used by the industry. Possible effects of mid-field blasts on structures and further research ideas will be suggested.

Jan 21, 2025

By D. J. Goodings, R. J. Bonenberger, H. U. Leiste, W. L. Foumey

This paper describes a series of two-dimensional tests conducted and filmed with a high-speed (500 frames per second) video camera. The purpose of these tests was to provide a better understanding of the processes involved in creating craters and channels in water covered soils with explosives.

Jan 1, 2000

By Tapan Goswami, Lloyd Hain, Geoff Brent

For many years Ramp 24 at Ensham mine in Queensland, Australia has suffered substantial coal loss and damage due to the fragile nature of the coal and problematic geological conditions, which have proved very challenging. In the past various blasting techniques were applied in attempts to improve coal recovery. One approach was to use a shallow throw (cast) blast followed by a separate post-strip blast underneath. Another method was the introduction of the practice known as “baby decking” with the addition of a large buffer of material in front of the coal. However, despite increasing mining costs, none of these techniques adequately reduced coal edge loss and damage.

Jan 1, 2008

By Bilegt Batbold, Bayu Saputra, Chris Batten

The ability to fire multiple blasts simultaneously can provide significant benefits to any open pit mining operation. Reduced blast-related downtime by reducing blast events can increase equipment utilization and maximize material movement. Significant sequencing benefits can also be delivered, associated with reduced equipment relocation. This paper describes the work completed in partnership between Orica and Oyu Tolgoi to successfully demonstrate that combined production-trim and midsplit blasting could be implemented successfully while successfully managing the risk of increased damage to the final walls. The paper details the methodology used to assess key performance measures linked to final wall damage and compares the performance between the following blasting methods. • Free face trim blasting vs. combined production-trim blasting • Presplit blasting vs. midsplit blasting. The results of the initial trial blasts are presented, along with the method agreed by the key site stakeholders for ongoing application. The method used to keep the risk of final wall damage to an acceptable level is explained, along with the benefits delivered to Oyu Tolgoi operations associated with the initial 12 months of application.

Jan 21, 2025

By Claude Cunningham

Difficulty has always attended the evaluation of rock breaking energy available from explosives, owing to the complexity of the way in which it is released, and the destructive amplitude of the pressures. Many problems have arisen and continue with this difficulty, including the following: I. Formulation of improved compositions to deliver appropriate energy levels to the blasthole walls, or to deliver previous results at improved cost. How appropriate is it to use various ingredients, such as Aluminium, water, salt? 2. Claims over energy issues, resulting in wasted time and expense, over things that sound good in theory but are very difficult to tie down. 3. Purchasers of explosives make decisions based on claimed “Bang per Buck” from different manufacturers, where the estimate of “Bang”comes from simplistic numbers from various, very unequal detonation codes. The above problems are escalating as time progresses. Using the high level IDeX PC 2000 detonation code, we have found a way to portray the differences between formulations in a way which relates to their breaking effect in the field. The basic method is to plot the adiabat from the detonation state to full expansion in units which express the practical implications. Energy alone cannot deliver results, so we use the curve to examine its manifestations: pressure and temperature. Internal energy is plotted with these. The method displaces relative energy numbers, as it portrays the context in which the energy is available. It is used here to compare an ANFO, an emulsion and a doped emulsion, as well as the effect of Aluminium. The effect of the shock pressure regimes and temperature correlate well with what is seen in the field.

Jan 1, 2000

By Sayantan Chakraborty, Kaushik Dey, SaKaushik Dey tyabrata Behera

Drilling and blasting is a popular excavation technique in the drift of underground mine. Faster completion of drift reduces the gestation period and thus longer blast pulls are attempted with longer drill holes. This compels the blasters to initiate higher charge quantity with higher confinements and ultimately results into blast-induced cracks beyond the desired periphery line of excavation. Assessment of the extent of these crack networks is difficult and often neglected. Near-field ground vibration models are often used as damage predictors (Dey, 2007, Yang et.al 1993, Holmberg et. Al 1979) but not necessarily deals with the positions of the cracks. Qualitative measurement of actual damage extent often measured using some geophysical tools, namely, P-wave velocity (Tezuka, 1995), seismic imaging (Dey, 2011), bore hole pressure monitoring (Brent and Smith, 1996), electrical resistivity (Grady and Kipp, 1993), GPR (Adams et.al, 1993) etc. Ground Penetrating Radar (GPR) is a similar geo-physical tool, which uses Electro-magnetic (EM) pulse for characterizing the medium. Similar to other geo-physical tools, GPR also comprises of a transmitter and one/multiple receivers to generate the EM pulse and receive the same after reflection/refraction from the medium(s) respectively. After its development in 1970s, GPR gained increased popularity due to its application in many important fields, namely, identification of buried objects, geological characterization, identification of geological disturbances etc. Thus, it is felt that GPR technique can be used to detect the invisible cracks inside the rockmass from the rock surface (wall and roof) itself. Understanding the same, field experimentations are carried out in an underground manganese mine in Central India, which operates on the ‘cut and fill’ method of mining at a depth of around 300m from the surface. Wedge cut blasting is carried out in the horizontal drifts of the mine using suitable blast design. A 1.6 GHz antenna was used for the GPR scanning, in which GPR transmitter transmits signals predominantly of the said frequencies. The signals get reflected back from any type of interfaces between materials in the target area, with different dielectric properties and is received by the receiver part of the ‘trans-receiver’ antenna and memorized in the Data Acquisition Unit (DAU). The data acquired is processed using a software. Ground vibration monitoring of the blasts are also carried out to develop a vibration predictor. The numerical analysis of near-field vibration predictor model results into the estimated vibration levels at the point of identified cracks. Introduction

Jan 1, 2019

By S. K. Chan, C. Badeen, S. Goldthorp, H. Feng, I. Alilovic, R. Turcotte

Over the last few decades, water-based explosives and their precursors, despite their apparent insensitivity, have been involved in a number of accidents around the world. A large proportion of these accidents occurred when these emulsions were pumped either for their manufacture, transport, or handling. In Canada, this has led to the development of “Guidelines for the Pumping of Water-Based Explosive”, which state that “using pumping pressures well below the laboratory measured minimum burning pressure (MBP) of the corresponding emulsions or watergels is a good safety practice”. However, in the above document, there is no description on how the MBP should be measured. In the last few years, a research program at the Canadian Explosives Research Laboratory (CERL) in collaboration with Orica has been focused on the development of a validated measurement protocol for realistic MBP measurements.

Jan 1, 2014

By Enrique Munaretti, Vitor Rosenhaim, Jair Carlos Koppe, Joao Francisco Feijo

The B3 mine is a multiple coal seam strip mining in operation in Rio Grande do Sul, the southernmost state in Brazil. A traditional truck & excavator operation is used to remove the overburden and selectively mine coal seams, ranging in thickness from 30 cm (1 ft) to 2.5 m (8.2 ft). Blasting is required in order to excavate part of the sedimentary rock overburden where the rock is too hard for mechanical excavation, and to mine the coal seams, selectively.

Jan 1, 2012