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By Viktor Aranovich, Thomas E. Brown

The Almalyk Integrated Mining and Metallurgical Plant is located near Tashkant in Uzbekistan and is one of the former Soviet Union's largest copper producers. Almalyk consumes about 10,000 metric tonnes of explosives annually and expects this requirement to double by the end of the century as they implement a program to boost mine output.

Jan 1, 1998

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 Sam Taoum, Omar Riahi

Few tools allow for accurately tracking ore dilution after blasting. Existing methods often rely on data analysis or linear interpolation of velocity, which can be imprecise and less effective in varied geological settings. A promising alternative is the use of numerical simulations, which involve complex mathematical calculations incorporating real physical data about explosives and geological characteristics. These simulations can model blast-induced fragmentation and subsequent ore dilution with greater accuracy, providing detailed insights into blast dynamics by considering factors such as explosive type, blast pattern, and rock properties. Numerical simulations integrate data from sources like seismic sensors, blast monitoring equipment, and geological surveys, offering a holistic view that single-method approaches cannot match. By simulating different scenarios, mines can predict the outcomes of various blasting strategies, optimize blast designs to minimize ore dilution, and maximize recovery. Advanced numerical simulations enhance the prediction of fragmentation distribution and size post-blast, crucial for effective dilution control and maximizing ore recovery rates.

Jan 21, 2025

By Cathy Aimone-Martin, Kristin Dunlap Kolden

Blasting was conducted for the Army Corps of Engineers (Corps) in the Columbia River near Saint Helens, Oregon during 2009 and 2010 to deepen the navigation channel as a final phase of a dredging project to accommodate larger container ships. The Columbia River Channel Improvement Project (CRCI) required 4 months to blast and dredge 300,000 yd3 (229,366 m3) of basalt from the bottom of the channel to allow Post-Panamax vessels with drafts up to 50 ft (15.2 m) access to the Ports along the River. Explosives charges were limited to 90 lbs (40.8 kg) per delay for the protection of fish and marine life in the area. A fish mortality study and marine mammal monitoring program was also required by the Corps. Underwater overpressure monitoring was required for each blast and peak overpressures measured 10 ft (3.1 m) above the river bottom 140 ft (42.7 m) from the closest blast hole were not to exceed 70 psi (483 kPa) with a cautionary level of 40 psi (276 kPa). Specifications required sampling rates of 500k S/s and PCB Peizotronics tourmaline pressure sensors. The Corps granted permission to co-locate additional ceramic-type sensors at different sampling rates to design redundant monitoring systems 140 and 300 ft (42.7 and 91.4 m) from blasting and develop a site-specific overpressure attenuation model for the project. This paper presents the correlations of overpressure with cube-root scaled distance factors, a comparison of measurements using three different pressure sensor systems, and a discussion of blast design influence on overpressure measurements.

Jan 1, 2014

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 Dan McCutchen, Oettmeier

Kelly bar drilling and blasting is unique to Florida, the' Bahamas and other marine limestone areas in the world where blast holes are required but will not remain open for the loading of explosives. This type of rock formation usually yields 1.5 tons of recoverable rock compared to 2.2 tons per cubic yard for competent limestone. The loss of .7 tons per cubic yard is due to voids and sand in the formation. These deposits all contain water to the top of the blast holes which are collared only a few ft. above the ground water level. The working pit is a water filled lake which is excavated from the bank by draglines. These drills have been used in Florida for many years to depths of 65 ft or less.

Jan 1, 1991

By Ronald W. Roberts

For years, blasters have experienced near-misses, injuries, and yes, even fatalities as a result of the dangerous nature of our business. Yet, some blasters continue to portray the immortal attitude: nothing-would-or-could-ever-happened-to me syndrome. As we all know, that attitude can become disastrous to yourself or colleague(s).

Jan 1, 1996

By Ricardo Chavex, Adrien Letellier

Flyrock remains one of the most critical issues in open-pit blasting. Despite the significant improvements made with modern surveying methods, the necessity remains to define sensible danger zones around blasting areas. Therefore, many semi-empirical models predict flyrock distances based on trajectory calculations and probabilistic adjustments. However, most are merely based on nominal parameters, even though a considerable amount of precise data is nowadays available thanks to modern measurement techniques using lasers, GPS, drones, and probes. These data provide accurate information about the actual field circumstances of a blast concerning geometry and rock-mass conditions. So how can we use and integrate them into existing flyrock models? The answer to this question can significantly improve the accuracy of flyrock prediction models and enhance safety. This paper will present a method to adapt existing models to actual field data using appropriate software and digital tools during the blast design process. In addition to calculating a more pertinent danger zone perimeter, this method provides an efficient and practical tool that helps prevent flyrock incidents. Indeed, it allows the blast designer and shot firer to be warned if there is a hazardous critical deviation due to local conditions. Moreover, it also enables blasters to communicate better and share the visualization of the blast-specific evacuation zone. The paper will also discuss how this method can be calibrated and how it has been used to analyze some actual flyrock incidents.

Jan 21, 2025

By Garfiansyah Rayes

In 2023, an Indonesian coal mine experienced significant contamination of an emulsion blend explosive by dynamic mud and water flow, triggered by flooding due to exceptionally high rainfall. This intrusion into explosive columns compromised the stability and efficiency of blasting operations, thereby impacting overall mining productivity. The extent and impact of these contaminants on the stability and performance of the emulsion blend explosive were rigorously analyzed through a robust assessment methodology that included comprehensive field measurements and controlled laboratory experiments designed to replicate the challenging site conditions. Utilizing a combination of theoretical calculations and Computational Fluid Dynamics (CFD) simulations, this study evaluates the kinetic interactions between dynamic mud flows and emulsion explosives within drill holes. The methodology integrates Torricelli’s theorem for velocity assessments and Darcy’s Law for understanding the penetration mechanics of mud into the emulsion blend. CFD simulations are further correlated with actual blast data to assess discrepancies between theoretical predictions and real-world outcomes. Results demonstrate a significant reduction in the velocity of detonation (VOD) of the explo-sives, traced directly to mud contamination levels, which align with the quantified penetration rates in the study. Practical measures for mitigating such contamination are proposed, including the reinforcement of water-ways, culverts, and bund walls at drilling locations based on validated simulation data. Additionally, rec-ommendations for operational adjustments during high rainfall events are discussed, aiming to enhance blasting safety and efficiency. The paper concludes by suggesting future research directions towards the development of more resilient emulsion formulations and enhanced predictive modeling techniques to better forecast the impacts of en-vironmental variables on explosive performance in mining operations

Jan 21, 2025

By Brian Hawkins, David Bradley, Rachel Gooding, Lucas Rodriguez, Patrick Wilson, Kevin Wegman, Dhruv Mittal

The Department of Homeland Security (DHS) has undertaken a probabilistic risk assessment (PRA) approach to quantifying the infrequent, yet high-impact explosive terrorist attacks on the United States (US) homeland and aiding in mitigating that risk through efforts ranging from intelligence gathering, defense postures, detection architectures, partnering with industry to prevent acquisition, and informed medical response. Based on an evaluation of existing model options, a path to the realization of an exterior explosive model (EEM) that builds upon existing models while meeting runtime requirements, maintains consistency with existing DHS chemical, biological, radiological, and nuclear (CBRN) consequence models, and provides sound estimates of the human health consequences of explosive terrorism attacks in open-air urban and rural environments.

Jan 1, 2018

By Andreas Gaich

A new 3D fragmentation analysis method for muck piles is presented. It works with aerial imagery from UAVs (drones) and handles entire muck piles with minimum user intervention.

Feb 1, 2020

By Robert Hopler

THE KEYSTONE NATIONAL POWDER COMPANY is an Independent organization, incorporated under the laws of the State of Pennsylvania. It has three dynamite mills near Emporium, Pa., with a daily capacity of 165,000 pounds. It maintains branch offices in practically all the largest cities east of the Rocky Mountains, and has distributing magazines located in every section where there is a demand for high explosives, with facilities for wagon deliveries. Our mills are all of modern type and are equipped with the most improved machinery for the manufacture of high explosives. The efficiency of our laboratory in conjunction with the high class of labor employed, has enabled us to put on the market an explosive, the quality of which is the result of extensive research and scientific knowledge. Our modern and complete equipment for harbor and railroad transportation insures our patrons of prompt deliveries, which is an essential feature particularly to contractors and those whose facilities for storage are limited.

Jan 1, 2013

By Jose Pineda, Abraham Lindo

The Panama Metro System’s Network expansion involves excavating a launching shaft for a tunnel boring machine (TBM) to traverse beneath the Panama Canal. The blasting needed for this shaft construction poses significant challenges due to the presence of concrete walls encircling the excavation. These walls must remain intact throughout construction and the tunnel's future operation. This case study is focused on devising and implementing safe blasting techniques crucial for the shaft's construction, ensuring the preservation of surrounding concrete walls and project equipment. As the interest was potential damage to the concrete walls, an appropriate vibration threshold for this project was also required as an alternative to the traditional U.S. Bureau of Mining RI-8507 limit (USBM RI8507). Blast modeling software was employed to conduct a series of blasting simulations. Parameters like hole diameter, spacing, depth, explosive type, and initiation methods were varied to evaluate their potential effects on wall stability and damage risk. The simulations revealed that smaller diameter holes and reduced spacing between blast holes would effectively mitigate the risk of wall instability. Additionally, utilizing electronic delay detonators and carefully planning the blast hole detonation sequence proved critical in minimizing potential damage. Executing these blasts in the field presented unique challenges, including strict charge per delay thresholds and logistical constraints. Consequently, continuous adjustments to blasting parameters were made and comparative result analysis. Beyond providing a safe blasting strategy for the TBM launching shaft, this study offers invaluable insights into adapting blasting designs to align with environmental and structural safety standards. These findings hold great potential to shape guidelines for analogous sensitive construction projects. They underscore the importance of leveraging prior research as a reference point, engaging with project designers and local authorities, and continually conducting testing and adjustments to ensure project success.

Jan 21, 2025

By Jennifer Williams, Donald J. Berger

Originally built between 1913 and 1916, the Ashton Dam & Hydroelectric Facility has experienced various seepage and piping incidents since completion. Ashton Dam is located within 15 miles (24 km) of the historical Teton Dam failure site and about 2.3 miles (3.7 km) west of Ashton, Idaho. Numerous repairs conducted over the years ranged from filling sinkholes on the crest of the dam to placement of rockfill on the upstream slope to improve seismic stability. In addition, the existing low level outlet works was grouted full and abandoned in 1991 due to significant vibrations induced on the dam during its operation.

Jan 1, 2014

By S. Behera, K. Dey

This paper presents a methodology for finite element (FE) modelling to analyse the total deformation of rockmass under blast-load, with a focus on predicting backbreak that may occur during surface blasting operations. Backbreak can result from improper use of explosive energy, leading to damage beyond the excavation zone and jeopardizing operational safety and productivity. The paper highlights the impacts of backbreak on bench stability, excavator operation, drilling operation, flyrock generation, and improper fragmentation and boulder formation in surface blasting. However, prior estimation of extent of rock breakage zone can provide an idea to formulate the blast design to control the backbreak. While vibration-based prediction models are commonly used to estimate backbreak, they require physical blasting experimentation. To overcome this limitation, the paper describes the development of a FE model using ANSYS Explicit dynamics, which simulates rock blasting and calculates the total deformation of the rockmass. The rockmass deformation is modelled using Drucker-Prager (D-P) strength model with the Jones-Wilkins-Lee (JWL) equation of state for the explosives. The accuracy of the FE model is evaluated through physical experiments, and the results are compared with the vibration models. The FE model demonstrates close proximity to physical observations as well as vibration model result in predicting backbreak, thereby offering a promising alternative to vibration-based prediction models. The primary objective of the study is to predict the response of the insitu rockmass to explosive blast loading and determine the effective rock breakage zone.

Jan 1, 2024

By Tapan Goswami

The main objective of the blasting phase in a coal mining operation is to maximise the coal recovery. However, coal loss due to blasting is a serious problem. The Australian Coal Association Research Programme (ACARP) reported in 2011 that in Australia one in every ten coal mines is completely wasted due to such losses. Coal is either lost in the spoil, largely due to the blasting operation or becomes diluted and cannot be recovered entirely. The major coal loss mechanisms include losses from the coal seam roof, the floor, the front edge and from dilution. Coal damage and loss mechanisms during cast blasting that have been observed by various authors include: •Excessive cast dragging the coal edge in the cast direction. Movements of this nature are oftenassociated with the formation of trenches. •Spatial movement of overburden where rock shears and moves in a plane above the coal seam,which damages and dilutes the coal. •Rock falling over the coal during the blast often producing indentations in the exposed coal. •The inappropriate use of bulk and initiating explosives that often results in coal damage. •Insufficient stand-off distances from the coal. The Australian coal mining industry has gone a long way towards addressing the coal loss issues since 2011: almost all operations now deploy touch-coal drilling and sporadically use gamma logging for loading overburden. A study was conducted to compare the effectiveness of touch-coal information in which some touch-coal blastholes were drilled on a fixed or random pattern. In another study, some blastholes were drilled to the touch-coal, gamma-logged and mapped to determine stand-off distances. It was found that the coal roof surface created by gamma-logged holes was the most effective option for minimising coal loss. As a result, a variable stand-off distance was found to be the key to minimising losses. This paper discusses the importance of coal mapping, the rock properties of the roof and floor interface of the coal seam, and the significance of loading and initiating designs in minimising coal damage. Furthermore, the importance of using electronic initiators cannot be emphasised enough. This paper also discusses how a cast blast can be initiated from many locations by mitigating geological abnormalities and thereby avoiding spatial movement of rock shearing in a plane above the coal seam.

By Tapan Goswami

This paper discusses the importance of coal mapping, the rock properties of the roof and floor interface of the coal seam, and the significance of loading and initiating designs in minimising coal damage. Furthermore, the importance of using electronic initiators cannot be emphasised enough. This paper also discusses how a cast blast can be initiated from many locations by mitigating geological abnormalities and thereby avoiding spatial movement of rock shearing in a plane above the coal seam.

Feb 1, 2020

By Per-Anders Persson

TIGERWIN, now on CD, is a user-friendly personal computer code (running under Windows) which determines the detonation and expansion state of an explosive from its known chemical composition. TIGERWIN is intended for users in the mining and commercial explosives industry who do not routinely program or run Fortran codes. The code allows the user to open a window on the computer screen and enter the initial density and the weight percentage composition of an explosive, ingredient by ingredient. Alternatively, the code can balance the composition with one or more ingredient percentages fixed, while proportionally adjusting the others automatically to give a total of 100%. The equation of state and its parameters can be user-selected from several proven and tested versions of the BKW, the JCZ, and the ideal gas equations of state. TIGERWIN allows the user to select several options for different additional calculations, such as determining the constant volume explosion, the Chapman-Jouguet (C-J) point, the detonation Hugoniot, the expansion isentrope from the C-J point, and point calculations with selectable specific volume and temperature. Additional options include calculations of detonation data with one or more ingredients partially reacted, assuming either temperature equilibrium between reaction products and unreacted material, or keeping the unreacted material “cold” at the initial temperature. Thus the code can run both ideal and non-ideal detonation calculations. The code automatically saves the input and output files in a separate directory for future reference. The output from several calculations can be displayed and printed in the form of a comparison table. In it, the key results of up to five calculations with different explosive compositions can be compared. The results from an individual calculation can be displayed graphically and printed with expansion work, pressure, or temperature as functions of specific volume. A complete listing of the details of the calculation results, similar to those from the original Fortran Tiger calculations, can also be displayed and printed. No computer experience is required to run the code and workshop participants are encouraged to bring in their own formulations to try out on TIGERWIN

Jan 1, 2000

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 Matias Suarez, Diego Zenteno

This paper is aimed to display the new advancements of blasting engineering done in different mining sites throughout the country, associated to electronic sequencing, energy of the explosive and its impact on the fragmented rock. This document explains how to define and implement selective sequencing in the blasting in order to promote the propagation of cracks, therefore impacting positively the productivity through the use of the LaGrange diagram. The LaGrange diagram is a very convenient and illustrative method to present the dynamic behavior associated with wave and crack propagation (Rossmanith. H, 2002).

Feb 1, 2020