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By Jesús V. Saccsa, Kenji B. Loayza, Erick M. Condori, Jorge A. Velásquez

This research investigates how to reduce manufacturing costs of a safety fuse composed of black powder, replacing its ingredient NO3K by NO3Na for processing, and contributing to minimize costs per blasting.

Jan 1, 2017

By Drew Martin

In March 2010 the Boral Linwood Quarry, Adelaide South Australia, implemented the blasting contractors Monte Carlo Blast Vibration Model as part of their blast design process. The Linwood Quarry was developing an area where blasting activities were marginally complying with the statutory vibration limits. Compliance to the statutory limits was only being achieved through the use of small blasts (less than 15 000 T (14 763 ton)) at a high cost to the quarry.

Jan 1, 2012

By N. Skopak, W. Birch, A. Douglas, C. Johnson

Determining the origins of air overpressure has been a long-debated topic within the explosives engineering community. Historically, it has been accepted that the initial face movement gave rise to air displacement, resulting in an air overpressure pulse. Later research proposed that the air overpressure pulse resulted from the shockwave rapidly propagating through and impacting the quarry face. Most recently, researchers have derived that air overpressure is associated with the gas phase from which a gaseous product from explosives rapidly pours out the quarry face under high pressure. Significant research has strongly indicated that the time at which the air overpressure pulse exits the face fails to coincide with either the arrival of the shockwave at the free face or the initial face movement. Research has consistently shown that the shockwave arrival at the face occurs before the air overpressure pulse leaves the face. Therefore, to best determine which blast mechanism contributed to the initial air overpressure pulse, testing was aimed at verifying the precise time at which the air overpressure exited the faces compared to when the face first moved. This research describes tests using scaled concrete blocks, which provided the ability to control the key parameters necessary for the research to be successfully concluded. Black powder was selected as the energetic material to eliminate the production of the detonation wave while still inducing other gas-producing effects. The components evaluated were air blast arrival times in front of the face, the initial movement of the blast face, the precise initiation time of the blast hole, timing of pressurization within the rock mass (between borehole and face, or adjacent borehole), and the speed of sound in the air. A detailed timeline was created which portrays the actions within the blast to promote an understanding of the sequencing of events. The results showed that the initial face movement occurred at 17.57 milliseconds (ms) while the calculated time at which the air overpressure exited the face occurred at 7.07 ms. The large disparity continues to reaffirm the premise that the origin fails to coincide with the air pressure pulse. Average pressurization through the block occurred at a rate of 341.23 feet per second (104.15 meters per second) which resulted in the gas release pulse being calculated to exit the face between 4.41 and 6.21 ms. This pulse correlates more accurately with the air overpressure origin timing which will be the focus of continued research. Knowing the precise origin of blast-induced air overpressure will assist in being able to better control it through appropriate blast design.

Jan 1, 2024

By X. Gumede

A model is being developed to quantify the benefits for mining houses resulting from the reduction in greenhouse gas and energy consumption by the application of innovative blast designs in addition to direct financial benefits throughout the mine to mill value chain. The conversion from shock tube initiation systems to electronics and some changes to powder factor measured on an open pit mine had previously been used to show significant improvement on blast outputs. Benefits were realised on drilling, blasting, loading, hauling and beneficiation. Quantification of the relationship between powder factor and reduced greenhouse gasses is investigated in this study. The study has highlighted new data that must be recorded and hence some assumptions were made as to fuel consumption and the energy in crushing was obtained from the Bond work equation. The mine to mill projects in an open pit platinum mine and a quarry produced energy savings and reduced greenhouse gas emissions associated with the careful application of explosives and blast innovations. The less fines project showed an increased carbon footprint. The model provides a new insight into how project feasibility should be decided based on economic and environmental viability.

Jan 1, 2012

By Tyler Acorn

In December of 2009 an estimated one million ton slope failure activated a 10 million ton mass impacting use of the main ramp system in the Newmont Gold Quarry pit. The failure left behind a 400 foot (122 meters), vertical to sub vertical scarp feature and shut down production in the lower benches of the pit.

Jan 1, 2011

By Francisco Sena Leite, Vincius Miranda, PhD Machado Leite, PhD Pinto, Raquel Carvalhinha, Alexandre Julio, Dorival de Carvalho

Rock blasting, in particularly the drilling process, is one of the first processes in the stage of rock fragmentation and plays a fundamental role by influencing all the following stages. Given its importance, some proposals to optimize this process have been presented over the last few years. These proposals, while having different approaches, aim (in a large part) to minimize the costs of drilling and blasting respecting the limits of fragmentation required by primary crushing. Reviewing some recent articles leads us to an enriching experience, since the authors of these articles clearly model the problem, but do not address the mathematical solution of these models, which in turn, given their non-linear nature, have no directly and easy solution. Simple and even robust optimizers present in the market show different results and often do not converge to a single solution. To address this problem, an adapted gradient heuristicbased model was developed to try to find optimum values. Heuristics search for values of stemming, subdrilling, burden and spacing that minimize the costs of blasting and drilling. This search, which by the nature of the heuristic moves the solution in the direction of the gradient with maximum decrease to find optimal solution, found values that in turn, when compared with values presented by market solutions not only equaled them as, in some situations, even improved the proposed solution. The algorithm was tested and validated on the field, and although the results have already been presented in papers published in the last year by the authors of this paper, it is now presented with its mathematical formulation and comparison with the other solutions. This approach is expected to be able to improve (and even demystify) the process of pattern expansion and be the basis for future work in the continuation of the optimization process.

Jan 1, 2019

By Toby Forney, Joshua Schoonover

In typical surface quarry operations, productivity and efficiency related to pit development begin with drilling and blasting efforts. By embedding technology within drilling and blasting operations, blast results can be tailored to benefit the quarry by driving continuous improvement of production. This technical paper will focus on the continuous improvement efforts at a cement limestone quarry in Maryland and how those efforts have impacted mining production, safety, and efficiency with the application of specific blasting technologies.

Feb 6, 2023

By H P. Rossmanith

This contribution addresses the advanced blasting technology which is based on wave propagation theory and fracture mechanics. The new concept of sonicity and the principle of maximizing sonicity in blasting as well as the energy or work of a blast operation will be introduced. It is shown that - in contrast to common belief – it is not the velocity of detonation which controls the blast but the relationship between velocity of detonation and the wave speeds, in other words, the Mach numbers of the blast operation. Based on numerous practical blasts in Germany, the authors show that, when using wave dynamic concepts, there is a linear relationship between peak particle velocity and the work of a blast operation and this linear relationship is controlled by the sonicity of the blast. Extensions to layered and faulted rock masses are presented. It will become clear that a second change of paradigm is enforced, the first one being the implementation of short time delaying. Again, the acquisition of knowledge in wave progation theory and fracture mechanics becomes mandatory in advanced blasting technology, where the art of blasting is now fully transformed into a science of blasting with little room for methods of trial and error.

Jan 1, 2010

By F. Schott, M. James, G. May, E. Baker, C. Johnson, R. Bauer

Explosive demolition typically utilizes cutting charges to sever columns, detonating cord to time charges and provide an initiation path, and dynamite as a kicker charge. The kicker charges of dynamite are used to “move” columns out of alignment, causing collapse. Demolition projects involving dynamite can pose significant health and safety risks to workers and the public. Nitroglycerin in dynamite can cause dizziness, fainting, and other health problems. Moreover, dynamite placed directly on columns can result in fragmentation and cutoffs, preventing other charges from being initiated and resulting in incomplete demolition. Fragmentation can occur from columns and travel significant distances from the initiation point, sometimes reaching hundreds of meters away. This fragmentation can pose serious dangers to anyone in the vicinity, including workers and members of the public, as the debris can cause severe injuries and property damage. The force and velocity of the fragmented material can be unpredictable and difficult to control, making it important to take proper safety precautions and consider alternative demolition methods that minimize the risk of fragmentation. Previous work concluded that casing charges in water showed that a reduced dynamite charge mass could still successfully kick the charge out of alignment. This study aims to investigate the use of Pentolite boosters in water-cased charges as a safer alternative to dynamite-based demolition. The research involved testing various amounts of dynamite and pentolite boosters in water to compare their effectiveness in moving a hanging W-beam, which swung freely like a ballistic pendulum. Water-cased charges consistently move the column at a higher velocity than the traditional dynamite charge placed directly on the column. The method of water-casing increased the area of impact and impulse felt by the column, improving demolition efficiency when compared to traditional demolition methods as found in previous studies. Pentolite water-cased charges moved the column at 7.8 meters/second (m/s) while the dynamite water charge moved the column at 5.9 m/s. The increased strength and explosive properties of the pentolite contributed to this increase in velocity. This study showed that it is feasible to remove dynamite from demolition projects by utilizing pentolite boosters and that when considering safety, explosive properties, and effectiveness, pentolite boosters can be cost effective as well.

Jan 1, 2024

By Edward P. O'Hern

The importance of the so-called explosives and the increasing extent of their use are evident from the fact that the production in the United States for the year 1910, as shown by the United States Census reports, amounted to the enormous total of approximately 480,000,000 pounds, this being more than double the production of 1905 and more than three and one-half times that of 1900

Jan 1, 2015

By Donald Jonson

Stockholm’s Northern Link, currently Europe’s largest urban road tunnel project, will be about 5 km long from west to east. Running through two separate, mostly parallel tunnels, each with 2-4 lanes, the complex will include numerous entries and exits, as well as a major branch to the north. The total length of tunnel will be 11 km, of which 9 km will be in rock. Over million m3 of rock will be blasted. The Northern Link will open to traffic in 2015. After a 10-year stop to deal with environmental questions regarding Ekoparken, Stockholm’s unique “national city park”, the Northern Link project in the Swedish capital was restarted in the autumn of 2006, with the construction of five works-access tunnels.

Jan 1, 2009

By Walter Voglauer

On May 14, 2011 a chimney blast took place in Vienna, Austria. The blasting operation was part of the demolition works at a former railway fabrication. The demolition works on this ground were done under the leadership of the Austrian construction and demolition company PORR. In agreement with the civil organizations which were involved, the commander of the Regional Military Command of Vienna, Brigadier general Dr. Karl SCHMIDSEDER ordered a reserve force engineer company to demolish the chimney. The concrete planning of the chimney blasting was done by specialist Markus SEWALD who belongs to the HEERESTRUPPENSCHULE (combined armed force school) of the Austrian armed forces.

Jan 1, 2013

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 John Brennan

Necessity, they say, is the mother of invention. Certainly that sentiment held true during the early stages of explosive engineering. While seaside forts were concerned over static ignition of their black powder caches in the 14th century1, the mining industry in the 1800s were plagued by accidents surrounding the ignition methods for their black powder blasts.

Jan 1, 2011

By B Kniivila, A B. Andrews, T Lerick, Keith Jansen

Minntac Mine is a large, open pit taconite mine located at the center of the Mesabi Iron Range in northern Minnesota. The planned development of the Mine in the direction of nearby communities prompted a comprehensive study of off-site blast effects that resulted in numerous refinements in blasting practices.

Jan 1, 1984

By Brandon Fryman, Josh Hoffman, Rhys Baker

A post-detonation debris collection project was led in conjunction with a large ammonium nitrate (AN) railcar detonation conducted by the Department of Homeland Security-Transportation Security Administration, Department of Defense-Combating Terrorism Technical Support Office, Sandia National Laboratories, and the U.S. Army Dugway Proving Grounds. This important work will aid in underpinning algorithms used in a Quantitative Risk Assessment (QRA) tool.

Feb 1, 2020

Controlled Blasting, Inc. (CBI) located in Norcross, Georgia recently teamed with the Dekalb county fire marshals office to stage a mock disaster to test new trainees of Community Emergency Response Team (CERT). It as an interesting example in which industry can help out the community and government through the use of explosives.

Jan 1, 2010

By William Reisz

Many different types of drills coming in a wide range of sizes and configurations are used in the blasting industry today. While each system may have its own unique attributes and capabilities, it may hold its own perils as well. This article will focus primarily on hazards that are mutual to most every type of drilling system.

Jan 1, 2013

By Ekin Güngor, Berkant Ozdemir, Erkan Bayrak, Serdar Ergün, Sedat Esen

"This paper presents the final wall blasting practices at Eldorado Kisladag Gold Mine in Turkey. Benchmark and improved wall control designs were explained in detail. Kisladag Mine has been implementing a high quality slope stability program on-site. The quality of pit walls is generally considered excellent, with very few wall failures being evident and with presplit hole barrels prominent in most areas of the pit. However, a minor scale slope failure occurred recently at the north-east section the pit. A project was initiated to diagnose the cause of the crest loss and evaluate ways to limit its effect on final walls. Final wall blasting practices and geotechnical designs were evaluated. The work presented in this paper showed that changes to the blasting and geotechnical parameters are required atthe north-east section of the pit. Geotechnical design changes were 10 m bench heights with 70 ° slope face angle at that specific area. Having implemented several geotechnical and blast design changes (elimination of the subdrill for the catch bench, appropriate primer location, more favorable blast tie-up and delays), the crest loss was minimized significantly (<1.5 m) (<5 ft)."

Jan 1, 2017

By D. Swanson

Cold Detonation Physics (CDP) is a patented new field of explosives and the name for the explosive that is produced when non-toxic dry ice (frozen carbon dioxide) is combined with powdered metals such as magnesium and aluminum, which are non-toxic and nitrogen-free. The explosive is detonator-sensitive and detonates according to the rapid reduction of carbon dioxide back to carbon, which produces solids comprised mainly of metal oxides and about 5% carbon. CDP was determined to produce a maximum of 300 liters of carbon dioxide per kilogram (4.81 ft3 /lb) and about 1.5 liters of carbon monoxide per kilogram (0.024 ft3 /lb). Both these figures shift according to metal content where higher metal produces less gases. According to theoretical modelling, the relationship between static pressure and metal content was determined to be an inverse parabolic curve with optimum pressure at 25% to 31% metal, depending on the type/s of metal/s used. Velocity of Detonation (VOD) was determined by measuring light at the wavefront with fiber-optic cable inserted into a series of holes drilled into the side of a 3-inch diameter (76 mm) schedule 40 steel pipe containing the mixture. The highest VOD was observed at 25% magnesium and measured between 2,500 to 4,500 m/s (8202 to 14,764 ft/s) when initiated by a 454-gram (1-pound) booster and an electric detonator. A 25% 50:50 alloy of magnesium and aluminum sample shot at a higher velocity than magnesium, according to how the alloy generated smaller pieces of shrapnel when compared with shrapnel from a magnesium test. CDP, using 25% alloy, was tested for blasting limestone by drilling 3.5-inch holes (89 mm) and inserting a 3-inch x 4-foot cardboard tube (76 mm x 1.22 m) with the mixture, packed to a density of 0.62 g/cm3 . The blast was initiated with an electric detonator, behaved like ANFO with more energy and fractured rock sufficiently across the entire length of the borehole. Seismic analysis determined that CDP produces lower ground vibrations than traditional explosives.

Jan 1, 2024