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By Ron Stewart, Richard Youmaran, Andy Adler

In the current context of heightened concerns with explosives security, there is significant interest in technological controls to improve security. It is important to be able to control what is fired, by whom, where and when. This paper describes research Orica has performed to investigate and test biometric systems to address the question of "by whom". The goal of this research is to incorporate the most suitable biometric system onto the 'blaster' unit of an electronic initiation system. This approach will ensure that only authorized personnel can initiate a blast involving electronic detonators. Requirements analysis: we initially explored many different biometric technologies to evaluate them against the requirements, including security, usability, ruggedness, size, form factor, privacy, and operational temperature range, This analysis identified chip based fingerprint sensors as the best candidate. Development of prototype units: in order to test the identified sensors, we modified standard, commercially-available, electronic blast initiation units ("blaster") to incorporate a fingerprint reader. Testing and evaluation: Biometric We conducted a biometric scenario evaluation in order to determine: 1) security level (measured by false accept rate (FAR)); 2) usability (measured by failure to enroll (FTE) and false reject rates (FRR)), and to 3) discover environment specific issues and challenges (such as temperature, humidity, dirt, or those related to the usage patterns of the user group). Tests were conducted at quarry sites in eastern Ontario, Canada. Results show rates of: FAR= 0%, FTE= 1.67%, FRR= 28.81%. Overall, these results suggest that this fingerprint biometric technology has a good level of usability in this application of electronic blast initiation control.

Jan 1, 2007

By D. Scott Scovira, Thomas Gustavsson

The potential of hydrogen peroxide explosives was introduced to Thomas Gustavsson and Robert Håkland by Dr Miguel Araos through his development of hydrogen peroxide gel compositions (HPG). In 2020, Thomas and Robert developed a concept project with Boliden Minerals and received Swedish government funding to evaluate HPG technology in a mine environment. The project showed HPG reacted violently with mine mineralization and concluded that HPGs did not offer a commercial solution due to safety concerns. Thomas and Robert engaged with Stefan Nilsson to develop hydrogen peroxide emulsion (HPE) compositions and the process techniques to manufacture them. In 2021, laboratory work produced a promising low carbon intensity, nitrate free, ammonia free, emulsion formulation based on industrial grade hydrogen peroxide and a fuel-emulsifier phase. Design and construction of an HPE pilot plant and underground charging unit commenced. The manufacture of hydrogen peroxide emulsion shares several similarities with the production of nitrate-based emulsions in that the plant is a facility to blend a strong oxidizer solution with a liquid fuel phase into a finished emulsion. A key differentiator between HPE and nitrate-based emulsion is that the manufacture of HPE is a cold production technology in that neither the oxidizer phase (HP) nor the fuel-emulsifier phase requires high temperature heating to prepare raw materials. A successful proof-of-concept HPE evaluation ran from April 2022 to October 2022 at Boliden’s Kankberg underground mine in Sweden. This evaluation demonstrated HPE technology's safety, performance, production, handling, and indicative environmental benefits.

Jan 21, 2025

By Raj K. Rajamani, Solomon A. Tucker, Michael K. McCarter

"In a study aimed at exploring possible improvements in operating performance at an Open Pit Copper (OPC) mine in the western U.S., the impact of blast energy changes on crushing performance was evaluated. OPC feeds its 3-stage crushing plant in 12-hour-day shifts with skarn ore from three domains: Pit_B (B), Pit_S Low-Grade (SLG) and Pit_S High-Grade (SHG), in the blending ratio 1:1:1 (B/SLG/SHG). Thecrushed product is fed to a 2-stage ball mill circuit. "

Jan 1, 2017

By S B. Richardson, D Mead, N T. Moxon

The use of air-decks to reduce explosive costs has become very topical in recent years. The majority of the research in this area has been arried out between the Soviet Union where reductions in explosive consumption of between 10-30% have been claimed with apparent benefits being gained in both fragmentation and movement. Work carried out by the University of Maryland using thick plexiglass blocks has supported these findings and indicated that air-decks in measetbe duration of action of the shock wave on the surrounding material by a factor of 2 to 5 (see Figure 1). Although the fracture network resulting from this mechanism is not as intense as that produced adjacent to the explosive charge it does appear to act over a larger volume of material. Although the mechanism attributed to air-decking has been studied in some detail the effect of this mechanism on the size distribution of material produced during a blast does not appear tot have attracted much attention.

Jan 1, 1991

By Jeffrey Meissner, Mike Waldron, Charles Dowding

Most studies of crack response have focused on opening and closing of a crack in the plane of the wall in which the crack occurs. Crack movement also occurs perpendicular or normal to the plane of the wall. This paper will examine and compare the in-plane and out-of-plane (normal) response of cracks in two different residences near limestone quarries. In two locations, sensors that measure in-plane and normal displacement were installed side-by-side on the same crack, allowing direct comparison of the two modes of response. In a third location, a perpendicular pair of displacement sensors was installed in a corner of a room to observe the bidirectional response of the structure at a corner. Both long-term and dynamic data were recorded with the same sensors; temperature, humidity, and air over pressures were also recorded to compare blast and weather effects. Measurements show that ratios of out of plane to in plane response to dynamic events can vary. However, the ratios of out of plane (normal) response to vibratory events to that of climatological change is still as small as the ratio for in plane crack responses.

Jan 1, 2010

By Stephen Mansfield

In metalliferous mining operations, subdrill is that portion of the blast hole that is drilled below the target grade elevation, and in most cases loaded with explosives. Its primary aim is to enable efficient excavation down to the target floor level. Subdrill is often described as being expensive and that excessive subdrill should be avoided, as it can result in damage to the subsequent floor, lead to difficult drilling conditions and higher vibration levels. As a result, many operations aim to apply the bare minimum amount of subdrill in order to excavate to the target floor

Feb 1, 2020

By B. Winterberg, C. Lewis, M. Starkel, C. Johnson

Non-electric systems, specifically shock tube, have become the pyrotechnic detonator of choice over electric due to their safety regarding accidental initiation from stray radio signals. Typically, the best practice when hooking up shock tube systems is to have direct contact to ensure initiation. When gaps are introduced to the explosives chain, there is potential for detonation to come to a halt. It is understood that direct coupling is required between the various elements in the explosive chain to ensure detonation. This holds true whether tying in non-electric detonators, loading holes in a mining related blast, or priming a block of C-4. Poor contact and gaps in the explosives chain can lead to detonators firing out sequence, leading to increased vibration, air overpressure, and other undesirable blast results. Furthering work conducted in previous experimentation, a new study was conducted at the Missouri University of Science and Technology’s Experimental Mine in Rolla, Missouri to observe the initiation potential of an air gap and fragmentation on non-electric shock tube. A series of small test blasts were conducted using 50 grain detonating cord and fragments from a blasting cap to initiate a non-electric shock tube across an air gap of varying distances. The data collected in the high-speed imagery was used to analyze the velocity of the pressure fronts and blasting cap fragments used to initiate non-electric shock tubes across an air gap. It was found that the shock tube was sensitive to 50 grain det cord at a 5cm (1.97in) distance while parallel and 10cm (3.94in) when perpendicular as well as sensitive to frag from the electric cap out to 2.4m (7.87ft).

Jan 1, 2024

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 Daniel Scott

Mines have used explosives for economical fragmentation for many years. It can therefore be expected that the mining industry has thoroughly researched how to achieve the most efficient blast. However, there is still a large amount of iteration that must be undertaken before blasting at a mine site can be refined enough to allow for consecutively successful blast results. And then the geology changes. This paper will present an approach to blast design that considers production goals, geology, budget, and safety, and will contrast the proposed method with well established blasting theory.

Jan 1, 2012

By Sven-Erik Johansson, Gosta Rundqvist, Donald Jonson

In Stockholm a new road traffic system called Södra Länken (Southern Link) will be in operation in late 2004. The total length of the road system is 6 kilometres of which 4,5 kilometres run through tunnels under suburbs immediately south of Stockholm inner City. The new traffic tunnels together with existing Metro tunnels, which mostly are in rock, will be the determining factor for blast design for many projects in the future. To set reasonable and safe permitted vibration levels the Swedish National Road Administration, Stockholm Region and Stockholm Transport Rail System have together financed a project to determine guide levels for blast-induced vibrations in traffic tunnels in rock. The purpose of the project has been to establish guide levels that are appropriate for different types of rock tunnels.

Jan 1, 2004

By Jaco van den Berg, Dr. Todor Petrov, Dr. Josh Calnan, Dr. Jhon Silva

This paper shows and reviews the similitudes and differences in explosions generated by high explosives and gas explosions, the reasons why gas explosions are difficult to replicate using high explosives, and the considerations when performing explosive testing using methane gases and coal dust.

Feb 1, 2020

By B Mohanty, A Siamaki, K Esmaeili

Large scale open pit mining and quarrying operations dictate safe and reliable pit wall stability. The current approach of employing the particle velocity-scaled charge distance approach to estimate and minimize damage to residential structures is considered inadequate to protect rock slopes. This study utilizes close-in blasting vibration data as input to an advanced 2D numerical code to study its applicability to serve as a predictive tool in terms of blast-induced rock slope failure. Two tri-axial accelerometer stations, consisting of high-frequency and high-amplitude (20 kHz, 100g) sensors, located within ~100m of the blast, but at two different bench levels, were used to monitor production blasts in a limestone quarry. The production blast consisted of double-decked explosive loads in 125 mm (5 in) diameter holes, with an inter-deck delay of 42 ms, and each deck consisting of 130 kg (285 lb) of emulsion explosive. The blasting vibration data obtained at the two bench levels were critically analyzed, and the vibration results served as input to the numerical model consisting of a single rock block with a 45 degree persistent joint plane but with specified strength properties, significantly different from that of the intact rock. The model was able to characterise progressive accumulation of damage in the form of microcracks along the joint surface as a function of the relatively low vibration load from successive explosive decks. The results showed that such a numerical model can serve as a very good diagnostic and predictive tool, when backed up by careful vibration monitoring and further supported by detailed slope monitoring.

Jan 1, 2017

By Martti Hagfors, Jussi Saavalainen

The underwater explosions has been used as a test method for the determination energy content of explosives. The test method is suitable for all kind of explosives; homogeneous, heterogeneous, wa-ter-resistant, no-water resistant, cap sensitive, booster sensitive, explosives with hard confinement, explosives without confinement etc. It is also the only test method by which shock, gas heave and to-tal energy values of the explosives can be measured separately. This feature makes it possible to use the test method to develop the explosives for different purposes; the military high explosives need more shock energy where as the gas heave energy is very important feature for the blasting and sea mine explosives.

Jan 1, 2010

By W B. Gregg

"A review, update, and expansion of Thiokol’s presentation at BAl’s Fiih High Tech Seminar titled ‘ADetonator - An Era of Precision in All-Electronic Detonators” is provided herein (and should be considered as a supplement to that publication). Thiokol is currently in the development and field evaluation phase of activities for our ACCUBLASTTM all-electronic detonator. The ACCUBLASTTM detonator uses a semiconductor bridge (an electronic match) in place of a conventional hot wire to initiate a safer, less sensitive material, titanium subhydride potassium perchlorate. The device is programmable to provide blast delays in one millisecond increments ranging from 1 to 500 milliseconds. The ACCUBLASTTM detonator combines an all-electronic programmable timer coupled with a semiconductor bridge to ensure detonation timing accuracy with +I00 microsecond precision. Initial development and field testing have been completed. These tests have verified ACCUBLASTTM detonators’ precision."

Jan 1, 1995

By Corry Goumans

Description of Project: Drilling, Blasting and Installation of Catenary Cables. Project Owner: Rio Tinto Alcan

Jan 1, 2010

By Rolf Schillinger

Transport of Small Quantities of Explosives Material on Public Roads The transport of dangerous goods on public roads is extensively regulated by EU and national law. The transport of explosive material is not only done by forwarders but also by small companies and private persons with the goal of their own use. The following article tries to explain what is allowed and what is not.

Jan 1, 2010

By C E. Johnson, S Hosein

Previous researchers have put forward two different theories as to the origin of air overpressure from quarry blasting. In 1980, Siskind et al postulated that the initial face movement gave rise to the displacement of air and that this resulted in the air overpressure pulse. However in 1990 McKenzie et al carried out research that indicated that the air overpressure pulse came into being as a consequence of the shock wave created by the detention of the explosive charge in a blast hole. In an attempt to evaluate these hypotheses, an investigation was undertaken over a 4-year period with the aim of determining the precise origin of air overpressure. The research was carried out at a chalk quarry in the North of England.

Jan 1, 2017

By Joshua Hofman, Braden Lusk, Erin Morris

Explosions in urban environments, whether of accidental or malicious cause, often result in extensive injuries, loss of life, and property damage. The ability to predict the damage inflicted by these events is highly sought after; in order to predict damage, the behavior of blast waves within these environments must be quantified and understood. Urban constructs such as buildings and roadway intersections affect the natural propagation of a blast wave, intensifying or rarefying the wave depending on their arrangement.

Jan 1, 2012

By G Mendoza, L Taddei, C Robertson

It is a well-known industry fact that many mine sites around the globe experience blast holes that have elevated temperatures due to reactive ground, geochemical reactions, geomorphic reactions, sub level open fires, etc. It has been reported in many previous industry publications (White, Saputra et al) that elevated blast hole temperatures are a norm at many mine sites and are dealt with on an ongoing basis while the drill and blast process continues under elevated states of alert. The choice of explosives products including the type of detonator, primer, accessory, and bulk product all must be taken into consideration when loading blast holes where there is a known potential for elevated temperature conditions. It should also be noted that these elevated temperatures inside blast holes can be consistent throughout the blast hole length or vary in position within the blast hole depending on the mine conditions mentioned in the opening statement above. The risks associated with the loading of primers and bulk explosives in holes where elevated temperatures are present include: the ejection of the bulk explosives product, deflagration of the explosives during initiation of the blast or premature and uncontrolled initiation of a blast hole(s). This paper describes a unique and novel approach to the active monitoring of the temperature within blast holes with the application of electronic detonators with integrated temperature measuring (ITM) capabilities, deployed and demonstrated at a mine site in Mexico during January 2023 to March 2023. The deployment of ITM capable electronic detonators allows a user to monitor and record the real time temperature at multiple locations (e.g., toe, middle and collar) at each electronic detonator’s position within the blast hole, with the ability to react instantaneously to elevations in temperature reported. The measurement of the temperature can be for a single ITM electronic detonator, or simultaneous for an array of ITM electronic detonators, allowing for the potential for the data to be represented by a time/temperature/hole depth three-dimensional heat map. Changes in temperature at different borehole positions can vary, however, often the collar position is expected to be the most reactive due the combination of bulk explosive product and oxygen exposure, which can be confirmed with the application of the ITM electronic detonators. A mine site’s reaction to a measured elevated temperature within a blast hole can vary depending on the temperature measured and the change in temperature from the last measurement made. The study was found to produce real-time in-hole temperature information which was previously unobtainable without the introduction of another device. New and adaptive elevated temperature hole policies can be created and adapted proactively as real time information is received, leading to a safer mining operation.

Jan 21, 2025

By Jason Baird, Braden Lusk, Dominique Nolan, Allen Stults

Conical shaped charges have been used to penetrate rock for many years now. Examinations have been made looking at shaped charge liner geometry, material, and standoff, as well as explosive composition, confinement and initiation. Most of the testing conducted towards penetration rather than cratering has fallen within the realm of the petroleum industry and as such been confined to specific rock types, with test apparatus that include simulated down hole (subterranean) environments. The testing conducted within this experimentation is conducted at ground level, in small scale samples, using a single standoff, against multiple rock types. The data collected from that testing is examined here and relationships between physical properties of the rock and the liner are analyzed. The analysis of that data raises the possibility of a relationship that may lead to new empirical methods of penetration prediction in rock.

Jan 1, 2012