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By William H. Snyer

A relatively inexpensive, very fast response photo-optic/fiberoptic system has been conceived, constructed and employed by Denver Research Institute (DRI) to measure charge breakout uniformity on the surface of a very large ANFO detonation. The new equipment and technique was coined OWL (observation without leads). Its unique design provides the ability to monitor or measure detonation velocities and/or detonation breakout characteristics without fiberoptic or any other direct contact with the explosive. This system has proven to be versatile and has been used to measure surface breakout simultaneity on large ANFO detonations, munition case breakout times and velocity of detonation (VOD).

Jan 1, 1990

By P. Ross, O. Rielo, P. Katsabanis

Selection of delay times to optimize fragmentation has been a controversial topic among researchers and blasting practitioners. The paper reviews all available experimental information, ranging from small and medium scale tests in geologic materials to small scale tests at the laboratory and synthetic materials, simulating rock. Tests have been re-analyzed and discussed in terms of the information they present and the limitation of the testing environment in representing actual conditions. New results obtained from blasting experiments in specimens made of a grout have provided a clear picture of the effect of delay on fragmentation. The grout used has a strength of 60 MPa (8700 psi), density of 2.5 g/cm3 and P-wave velocity of 4000 m/s (13100 ft/s). Each block was placed in a yoke to eliminate unwanted reflections and the desired delay was obtained using the appropriate length of detonating cord between holes or sub-millisecond electronic detonators. Delays ranged from 0.1 ms/m (0.03 ms/ft) of burden to 16 ms/m (4.9 ms/ft) of burden. Fragmentation was obtained using screen analysis of the collected fragments. Delay time has been shown to be a significant parameter affecting fragmentation and back break. Generally larger fragments and less back break was observed at short values, while fragmentation somewhat deteriorated at significant delay times, compared to what was observed at intermediate delay times. The work is now extended to include the effect of energy partition on fragmentation as well as the effect of initiation point and coupling ratio.

Jan 1, 2014

By Douglas Rudenko

Have you ever had a neighbor complain about a blast one day, but says the next day’s blast was better, even though the Peak Particle Velocity (PPV) increased? How about neighbors that complain about a small trimming shot, but don’t complain about a big production shot? Have you ever reduced the pounds/delay and gotten more complaints ? Mine operators are often bewildered when trying to correlate blast design parameters to homeowner complaints. When complaints come, standard practice is to set up a seismograph in the neighbor’s yard to monitor the blast. Immediately after the blast, the neighbor usually reappears from the house wanting to know the seismograph reading. When told that the PPV was 0.1 in/set, well below damage levels, the homeowner explodes saying “Your machine is wrong”. Perhaps he is right. Understanding why people complain about blasting is not about PPV, it’s all about structural response. People could care less about how much the ground vibrates; they only care about how much their house vibrates. In this paper we will examine the primary factors that control structural response. Through the use of a large array of digital seismographs, the effects of two production blasts on a community surrounding a quarry are studied. The predicted structural response resulting from each blast is calculated at 175 seismograph locations. The predicted response is then correlated to previous research on human perceptibility to vibrations. The results of this analysis and correlation give a better understanding of what the residents actually feel in their homes. The detonations of two single-hole signature blasts are also recorded by the array of seismographs revealing the dynamic characteristics of the geology ‘surrounding the quarry. Once the influence of the geology was understood, blasts were configured to disrupt the natural rhythm of the site through the use of millisecond delays.

Jan 1, 2000

By Douglas Rudenko

Have you ever had a neighbor complain about a blast one day, but says the next day’s blast was better, even though the Peak Particle Velocity (PPV) increased? How about neighbors that complain about a small trimming shot, but don’t complain about a big production shot? Have you ever reduced the pounds/delay and gotten more complaints? Mine operators are often bewildered when trying to correlate blast design parameters to homeowner complaints.

Jan 1, 2002

By Dean Nichols, Matt Ortel

Explosive accidents in the United States have brought increased attention to emergency operation plans (EOP) at all facilities that manufacture, transport, or store hazardous materials – particularly explosive materials. Explosions are sudden, powerful, and complex events that are difficult to characterize in terms of the thermal, over pressure, and debris effects. Industry, regulatory, and public officials require emergency response planners to not only anticipate the blast effects of an explosion, but also to prepare an appropriate response.

Jan 1, 2016

By Piotr Mertuszka

Many years of research on more effective and safer explosives have led to the development of emulsion explosives. They are the second most commonly used group of explosives worldwide, primarily because they are good alternatives to ANFO or dynamites. Their key advantage in underground applications is the lower content of toxic fumes in the detonation products. Emulsions are also characterized by high detonation velocity, high water resistance, low critical diameter, and mechanical loading capacity. Several factors affect the behavior of emulsion explosives. These factors are related to both manufacturing and applied mining methods. The most important factors include the charge diameter, type of sensitizer, density, hydrostatic pressure, ambient and charge temperatures, as well as the time elapsed between the charging of the explosive into the blast hole and its detonation. The selection of the type of explosive is based on the analysis of a number of parameters, including the density, critical diameter, volume of the post-blast fumes, detonation pressure, velocity of detonation, and sensitivity to external energy sources. In most cases, the conditions under which explosives are used differ significantly from those defined in standards. Such conditions cover, among others, the temperature of the rock mass and surroundings, humidity, rock strength parameters and the diameter of the blast holes. Consequently, the parameters of the explosives provided by the manufacturers may not correlate with those specified in-situ. Thus, within the framework of this study, the effects of the selected technological parameters on the detonation velocity of bulk emulsion explosives are presented. The analysis focused primarily on the factors directly influenced by the mine blasting services. The detonation velocity measured using the continuous wire resistance technique was used as the evaluation criterion. For this purpose, several underground in-situ tests were conducted, including the impact of the blast hole diameter, density, initiation method, sleeping time, and temperature on the detonation velocity. The results of in-situ tests have shown that the detonation velocity of bulk emulsion explosives depends strongly on the above factors, which may directly affect the effectiveness of blasting operations.

Jan 26, 2026

By Norman Kramer, Roger Keller

The authors would like to thank Austin Powder Company for their technical support and input, specifically Stephen Harris, Jason Ryan, and John Capers of Austin Powder, without whose support this paper would not have been possible. Thanks are also extended to Nick Francis of Sandia National Laboratories and Jim Houseworth of Duke Engineering for their input regarding Performance Assessment.

Jan 1, 2000

By Jerry Bennett

A recant Bureau of Mines analysis has shown that failure of blast area security systems is the mayor cause of mine blasting accidents. Accidents occur during scheduled blasting because of failure to clear the blast zone, inadequate guarding, and failure of personnel to follow instructions, retreat to a safe location and/or take adequate cover. The high incidence of blastslte security-related accidents could be considerably reduced by increased attention to improving minesite blast-guarding practices.

Jan 1, 1984

By Paul Worsey, Terry Nixon

The development and testing of a simple mechanical stemming aid (Patents pending) resulting from a Joint venture by Incubator Technologies Inc. and the University of Missouri-Rolla and funded by the U.S. Department of Energy is described. The aid comprises a solid unit placed in the stemming above the explosive column and is designed to improve blasting efficiency and reduce drilling and blasting costs. It works with back filled drill cuttings or any other suitable stemming material.

Jan 1, 1988

"Recently, an effort was made to calibrate the Riedel-Hiermaier-Thoma (RHT) material model to reproducethe behavior of granite under impact and explosive loading conditions. The study concluded that the materialmodel captured the phenomenon of compressional damage in granite due to such loading conditionsfairly well. The present work uses hydrodynamic modeling with the calibrated RHT model to estimate thefines generated around a blasthole. This can improve the calibration of different size-distribution empiricalmodels and enhance the prediction of fines."

Jan 1, 2012

By Brian Wingfield, Rick Givens, Greg Williams

Many technological advancements have been made in explosive products and applications over the last 15 years resulting in productivity and cost gains. However, the application of total energy (engine horsepower) in the majority of rotary drilling technology, has remained virtually unchanged over that period. While advancements have been made in components, efficiency, and types of hydraulic systems used on drills, the application of current hydraulic technology to improve drilling productivity has not been interactive with end users.

Jan 1, 1996

By Daniel Vargas Quispe, Yorhinio León Robles, Marco Jauregui Vargas, Helen Espinoza Bailon, Oshin Quispe Luya

This project describes the methodology applied during the execution of tests to determine the multiple controls that mitigate damage to the final walls of the pit. The different tests were executed on production pattern, which considered: modification of the angle of pre-split drill line, damage evaluation in individual drills with different load designs, varied detonation sequences, capture and analysis of elementary waves. After the evaluation and analysis of the results obtained in the tests, we are in process to standardize various damage controls such as; the combination of pre-split drill line angles at 80° and 90°; charge design in buffer drills that reduce the angle of action of the explosive and a detonation sequence that involves the creation of a relief filter that is made up of the detonation of two rows next to the pre-split drill line, which will have the function of filtering the waves of vibrations produced by the detonation of the production drills and at the same time it modifies the direction of damage towards the blasted material. The analysis of the different controls, as well as their combination, will allow us to improve the compliance results of the formation of benches.

Jan 21, 2025

By Joel Warneke, Cristian Caceres, Ed Mchugh

NIOSH researchers collected basic data from two blast rounds at the SSX-Steer Mine as a component of a larger study on controlled blasting, the goal of which is to reduce injuries from falling rocks in underground mines. Drilling and blasting procedures at the mine were observed. Rock mass property data were collected, a program of seismic monitoring and analysis was conducted, and 3-D laser survey scans of the workings before and after each blast were performed. The geologic data showed that the rock mass quality was characterized as poor to very poor. It was essentially uniform within the panels examined. The recorded seismic data indicated that fill material acted as an effective damper to seismic energy. The pre- and post-blast laser scans showed both over-break and under-break conditions, highlighting the problems associated with blasting a weak rock mass. By comparing the achieved results to the intended design, potential improvements in the drilling and blasting practices can be identified. Comparison of these data with similar data from other mines will help define how various combinations of rock and fill behave during blasting. Through studies such as these, data collection procedures and analysis techniques can be refined. An ultimate goal is to develop blast procedures tied to rock mass characteristics that can minimize damage to rock in the perimeter of the opening, limiting the amount of loose rock and improving the safety of miners.

Jan 1, 2008

By Carlos Enrique Arroyo Ortiz, Jadir Pedro Alves

This paper presents some of the results obtained during the research work about the use of technologies and digital transformation in the process of rock drilling in open pit mines. The use of automation presents itself as a disruptive factor and a driver of improvements that provide sustainability in rock drilling. Seven main operational parameters were utilized to combine measurement while the drilling (MWD) with other information generated by the equipment during hole drilling, in six different lithologies in an iron mine, located in the central region of Minas Gerais in Brazil. Adjustments and corrections were made to the data collected in order to minimize external influences other than the rock itself, to ensure the effectiveness of the analyses. Finally, we sought to compare the performance of the drilling process in manual and automatic operation modes. Thus, making it possible to show the efficiency and impact on the sustainability of rock drilling operations in open pit mines.

Feb 6, 2023

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 Ulrich Leiste

If the iron ore loss is 15% in the process of mining, the total iron ore loss in the world will be about 461 million tons, this is equal to the total production of 230 iron ore mines each of which produces 2 million-tons of iron ore per year. Based on a series of blast tests in the Malmberget mine, this paper shows that ore recovery can be markedly increased by improving blasting technology such as choosing a correct primer position and making use of shock wave collision. The paper further suggests that a high ore recovery can not only reduce natural resource loss and mining cost but also prolong the life of a mine. In addition, the paper shows an example of reducing blast-caused rock damage in the roofs and walls of underground drifts (tunnels) by using new blasting methods in the Malmberget mine. Finally, the paper shows how the Malmberget mine has successfully reduced the ground vibrations, without adversely affecting fragmentation and ore recovery in sublevel caving mining.

Jan 1, 2014

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 Emily Johnson, Catherine Johnson, Rachel Bauer, Paul Pitzel

Demolition projects involving explosives may incorporate cutting charges to sever columns in collaboration with kicker charges that “move” the columns out of alignment. Traditional kicker charges often involve the use of dynamite secured to the column above the cutting charge. Nitroglycerine, the main component of dynamite, causes medical problems and can be a hazard to workers on site. Dynamite can also cause fragmentation of the column and structures, resulting in potential injuries to people or leading to the possibility of cutoffs in neighboring charges. This study investigates the use of water-cased kicker charges to reduce the amount of dynamite in demolition. Water charges, traditional charges, and detonating cord charges were placed on hanging steel columns and analyzed for the fragmentation of the column and velocity of the column. A W 10 X 22 beam was hung in an underground limestone test area and allowed to swing freely acting as a severed column. Charges were attached to the bottom of the column with tape and initiated using electric detonators. Explosive charges of dynamite or detonating cord were placed in the center of a water container or directly on the column for use as the kicker charge. Tests were recorded with high-speed video and velocity was calculated using Phantom Camera Control software. Velocity and time were then used to calculate force, kinetic energy, impulse, and pressure exerted by the explosive on the column. The water charge transferred energy to the column over a larger area with no direct contact of explosive and the column. Water charges moved the column faster and with more power than traditional charges. After preliminary tests, water charges were also used as the primary kicker charges in a full-scale demolition project as a case study using 118 charges. The kicker charges successfully moved building members without creating fragmentation while using less dynamite than traditional kicker charges. Due to the success, multiple full-scale projects are being designed using water charges to show success and repeatability.

Feb 6, 2023

By Nick Lewis, Paulo Pereira

The Vulcan McCook quarry has been in operation for about 100 years. It is located about 17 miles from downtown Chicago and is surrounded by both industrial and private structures. Recent issues have forced the quarry to blast very close to structures and this will be necessary years into the future. This paper discusses the implementation of electronic detonators to McCook. It also discusses the advantages and savings that the Program has achieved

Jan 1, 2003

By Orica Chile, Orica Brasil, Orica Brasil Victor Morais, Kinross Paracatu Leopoldo Muñoz, Kinross Paracatu Luis Marinho, Gubio Barsottini, Orica Brasil José Vergara, Lucas Steffen, Orica Brasil Washington Vilas

In drill and blast activities, it has been a challenge to sculpt walls accordingly to what has been designed in state-of-art mining design software. Obviously, the perfection of making neat and smooth walls – using aggressive sources of energy, like explosives – are time-and-money consumable and, sometimes, even unnecessary. But undoubtedly, it is vital to guarantee solid walls, safe operations environment, beyond to avoid ore losses and pit constraints caused by poor rock breakage on detonation. Kinross Gold Corporation owns the biggest Brazilian Gold Mine, located in Minas Gerais state. Morro do Ouro mine has reached over 30 years of operation, and due its mature age, the complex has developed its pits, becoming them deeper and surrounded by high walls.

Feb 6, 2023