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By Luan Monteiro, Francisco Biulchi

The AngloGold Ashanti - Cuiaba mine sought innovative approaches to minimize lateral development and stope extraction time while maintaining optimal gold recovery and minimizing dilution. The stope 8GAL EXT 30 was selected as a case study. Traditionally, conventional blasting methods in such a scenario would necessitate either a single mass blast or slot development at each end of the stope. These methods typically compromise recovery and dilution or increase development time and risk. Additionally, conventional wired detonators require workers to re-enter the stope between blasts to load blastholes and connect detonators. The wireless initiation system offers a solution by initiating blastholes using magnetic induction signals that can penetrate rock, air, and water. This technology allows a pre-charged stope to be mined without requiring workers to re-enter the area between blasts to charge and connect blastholes. Engineers from Orica and AngloGold Ashanti designed a new extraction sequence utilizing the wireless initiation system. The process began with the opening of one end of the stope using a conventional slot and wired electronic detonators. Subsequently, pre-loaded rings were fired in three blasts to extract the opposite end and the intersection. The 8GAL EXT 30 stope was successfully mined using this technology enabled method. Each blast was meticulously monitored, and the stope void was scanned to assess blast performance. The results demonstrated a 4.6% improvement in recovery and a 16% reduction in dilution compared to the initial plan, and reduced exposure of people to hazardous locations in the stope. These results represent an additional value of USD 200k, gained from implementing wireless initiation to enable this particular blasting schedule.

Jan 21, 2025

By Timothy D. Stark

Blasters are usually strictly liable for injury or damage caused by flyrock (trespassory invasion) and blast-induced vibrations (non-trespassory invasion). The application of strict liability to non-trespassory invasions has resulted in significant litigation that has hampered the use of blasting and the blasting industry. Stark (2002) proposes that blasters should not be held strictly liable for non-trespassory invasions but should be liable only if their conduct is proven to be negligent. This change in legal standard was proposed because improvements in blasting technology over the last thirty years allow blasting to be conducted without substantial risk of harm to property and thus the amount of harm imposed by a blast can be related to the level of care exercised by the blaster. It is anticipated that negligence standard will reduce the amount of litigation because a plaintiff will have a greater burden to overcome. To facilitate the acceptance of negligence standard by a court of law, this paper illustrates the application of the negligence and strict tort liability frameworks using actual cases in which a decision was rendered. It is evident from these cases that some of the successful claims under the strict liability framework would not have been successful, and probably not litigated, under a negligence framework, which could result in substantial cost savings to the blasting industry and consumers.

Jan 1, 2004

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. Fourney

In the late 70’s and early 80’s in conjunction with other oil and gas well stimulation studies, personnel from the Dynamic Effects Lab performed model testing to demonstrate the effectiveness of utilizing an open section of borehole just before a plug. We called the process stem induced fracturing. The open section beneath the stem was used to increase the pressure magnitude and spread out the duration of the pressure pulse. This technique was later utilized to by Frank Chiapetta (1) in the fracture and fragmentation of rock in quarry blasting situations. He called his technique air deck blasting. In fact, Frank found that the Russians had previously discovered the same technique. There is currently interest in utilizing air deck blasting with an open section of hole beneath the explosive at the bottom of the bore hole to better remove the toe in a fragmentation shot. This paper reviews the development of stem induced fracturing and then describes a series of model tests conducted to measure borehole pressure at points along a borehole when an explosive charge is detonated at the midpoint of the borehole. Tests were conducted in both stiff boreholes (aluminum) and less rigid boreholes (PMMA-Plexiglas). Pressure time profiles were measured at the charge site, midway between the charge and the bottom of the hole, at the stemming at the top of the borehole, and at the bottom of the borehole. Crack initiation sites and crack propagation were also determined in the PMMA models. Some high speed pictures were taken of the event in the PMMA.

Jan 1, 2006

By B T. Lusk, John J. Silva Castro

The signature hole method uses a convolution operation to predict the waveform of a production blast based on the record of a waveform produced by a single blast hole. Convolution is a mathematical operation on two functions, (generally the product) to produce a third one. Recent research communication and publications highlight a lack of discussion in the literature about the available methodologies to calculate the convolution for blast vibration prediction. The goal of this paper is to discuss and present in detail for students in ground vibrations from blasting, several techniques to calculate the convolution between signals when the signature hole method is used. Convolution is a straightforward operation when signals produced by each hole are assumed the same, however; variations in the signals from each hole in a production blast require a more complex convolution operation. A graphical procedure is shown in this paper to solve a convolution when signals vary hole-to-hole (as expected in a mining production blast). The graphical methodology was tested using a recorded blast event and the results were compared to the regular mathematical procedure (convolution) and the results from a commercial software used in the mining industry. Results show that the graphical procedure is in agreement with the results from the other two.

Jan 1, 2014

By Andrew Wetherelt

Blast vibrations are of paramount importance in a society where ever increasing development is putting more stringent requirements on their control. Increasing civil development and more complex extraction scenarios make the trade off between proficient vibration control and productivity difficult to ascertain. Historically, reduction of induced vibrations levels was achieved through a reduction of MIC’s leading to smaller but more frequent blasts in order to meet extraction targets.

Jan 1, 2007

By CVB Cunningham

"The Kuz-Ram model as originally proposed included an error in assuming that the mean fragmentsize predicted by Kuznetsov’s equation was actually the 50% passing size. In 2003 Spathis began discussions on this issue and recommended correcting the equation. The correction produced more fines in the predicted fragmentation, which had been a criticism of some users of the original model. Ouchterlony subsequently showed that the error had, if anything been beneficial, and that the Swebrec function adequately covered the fines. This author shows that the Spathis correction does not assist the fines correction in examples examined, but tends to underestimate coarser fractions. An intrinsic problem of communication between academics and engineers is a root of misunderstanding on both sides, and requires patience by both parties to enable value to arise."

Jan 1, 2016

By Joshua Hoffman, Philip Mulligan, Braden Lusk, Tristan Worsey

Blasters rely upon detonators to achieve the designed timing sequence to move material where it needs to go, minimize vibration, or optimize fragmentation. At times detonator inventory on seldom used delays may be slow moving. This can lead to detonators being used long after they were manufactured. This paper addresses the potential shelf life concern as it relates to timing accuracy of shock tube detonators. A recent study was conducted to study the timing accuracy of non electric shock tube detonator systems. A follow up study was then conducted to determine the degradation of the non electric shock tube systems accuracy with time. The follow up study is presented in this paper. Samples of detonators from the initial study were set aside for approximately one year and then tested. The results from the aged detonators were compared to those of the detonators that were tested in the original study. As an extreme case a third set of shock tube detonators was tested using detonators that were between eight and nine years old. The results from these tests are presented as well. Each system was tested at a short medium and long delay time. Statistical analysis was conducted to determine the effect of time on the detonators accuracy. This paper quantifies the importance of regular inventory cycling to help preserve manufactured timing when using non electric shock tube detonator systems.

Jan 1, 2013

By Stewart A. Silling, D. Lynn Gordon, C. Mick Lownds, Dale S. Preece, Ali Bhuiyan, Patrick R. Bowden

Blast heave modeling and prediction utilizing the new discrete element model, GEM, that treats rock as elements with alternating arcs and line. Explosive loading of GEM elements is accomplished by utilizing the Noble-Abel equation of state to track the gas pressure from detonation through expansion to atmospheric pressure.

Feb 1, 2020

By Kerina Taylor

Due to their high amount of stored energy, explosives have been the cause of many serious injuries and fatalities over the last centuries. Despite safety advances and awareness in the last decades, injuries and fatalities continue to occur at mining operations due to blasting. According to the National Institute for Occupational Safety and Health, from 1978 to 2001, blasting incidents claimed 106 lives and were responsible for over 1000 injuries in mines in the US. The main causes of incidents found today are flyrock, blast area security and premature detonations. The concerted efforts of the mining and explosives industries and labour and government agencies have greatly improved the safety record of blasting in mines.

Jan 1, 2011

By G Alan Foster

Many complaints generated from blasting operations result from the marked human response to ground transmitted vibrations and air blast effects and so many authorities have considered the regulation of blasting in terms of human response rather than, as previously, in terms of preventing damage to structures.

Jan 1, 1981

By Alastair Torrance, George Boucher, Roger Keller

An investigative blast programme has been carried out to provide information on the best blasting methods to excavate Chek Lap Kok island in Hong Kong for the new airport. The objectives of the programme included the assessment of a range of blast design parameters and their influence on fragmentation. This has been evaluated by physical assessment, photo digitising of the muckpile and computer predictions. In addition, a model to predict the three dimensional muckpile shape has been successfully calibrated.

Jan 1, 1992

By John W. Brown

During the summer of 1994 the mining industry experienced numerous accidents involving blasting related incidents. The Tri-State Chapter of Explosives Engineers planned a meeting to discuss three of these accidents.

Jan 1, 1995

By Langdon T. Mitchell, Karl Ingmarsson

The title is not referring to jewelry; nor is it about diamond core drilling. This article is instead about an emerging application for diamonds, hard rock percussive drilling with diamond drill bits. Diamond’s outstanding wear resistance has long been taken advantage of in core drilling. However, until now diamond has been less successful in hard rock production drilling in the mining and quarry industry.

Jan 1, 1999

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 Tom Snyder, John Brulia

PART 3 – UN Identifi cation Markings for the Highway Transportation in Commerce of Bulk Explosives, Oxidizers, and Combustible Liquids

Jan 1, 2015

By Sebastián Seria, Jorge Álvarez, Diego Cáceres

The capacity to break the rock into adequate size fragments and in a cost-effective way is one of the main challenges in large open pit copper mines in Chile. That capacity is often compromised by the accuracy of geological estimations and the resources allocated by the mine site to update those models, making the blasting design highly dependent on that input and in consequence, blasting results. Given these opportunities, having an alternative method to input estimated key geological parameters allows blast designers to modify their designs and apply the appropriate energy to achieve the desired results. By using measurement-while-drilling data from boreholes and a few samples of actual, widespread, hardness measurements on site, we can deliver an updated cost-effective hardness estimation that is used as an input to improve the blasting design and its results on fragmentation. This estimation is delivered as a hardness interval – often in MPa units- related to the position of actual drilling measurements. In addition, having a sufficiently large drilling dataset allows us to predict hardness in new, undrilled areas near already measured boreholes, serving as a prior estimation available before pattern design. The use of these estimations, applied to several copper mines in Chile, allow us to more accurately determine explosive amounts and borehole drilling, which directly contributes to more productivity and efficiency in mine site operations. The results are often related to narrowing the gap for fragmentation results, even so, in some cases that will be related to direct savings in Drilling & Blasting process in a range 5-10% of the budget, due to powder factor changes.

Jan 26, 2026

By P A. Lang, J G. Ayotte, R W. Humphries

Atomic Energy of Canada Limited (AECL) has the responsibility for research, and development of technologies, for the safe and permanent disposal of Canada's nuclear fuel wastes. As part of this comprehensive program, AECL is constructing an Underground Research Laboratory (URL) near Lac du Bonnet, Manitoba, to evaluate aspects of the concept of waste disposal deep in stable geological formations. No nuclear wastes will be used in the URL program.

Jan 1, 1986

By Joshua Hoffman, William Chad Wedding, Braden Lusk

The emergence of electronic detonators as viable products for use in production mine blasting has enabled mining professionals to rethink the traditional blast design methodologies that pertain to timing. In many ways, electronic detonators can allow great advances in productivity, cost effectiveness, fragmentation, and safety. There are a number of commercially available systems that enable users to program delay times, usually in one-millisecond intervals, according to design decisions. While manufacturers have performed internal studies pertaining to the accuracy of these systems, an independent study quantifying the accuracy of the systems has not been completed to date. The mining industry is in the business of production and any quality control endeavors to independently confirm the accuracy studies performed by the manufacturers would only detract from their bottom lines. Furthermore, limited information is available concerning the accuracy of modern pyrotechnic delay based detonators. In 1985, the Bureau of mines completed a study of three manufacturers’ electric millisecond delay detonators (Bajpayee, 1985). This was the most recent extensive independent study performed on detonators, which unitized pyrotechnic delays, from numerous manufacturers. Advances in the manufacturing process for pyrotechnic delays may have increased the accuracy of detonators using these technologies in recent years. It is commonly accepted that electronic detonators are more accurate than both shock tube type non-electric as well as electric detonators, but the relative accuracy was not objectively and adequately quantified.

Jan 1, 2011

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