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By Crazy Horse - The Journal of Explosives Engineering - Vol 20 No 1

The crew at Crazy Horse Memorial has produced a w o n d e rful new video called “The Fine Art of Mountain Carving.” The video closely examines for the first time, the extraordinary explosives engineering on the Crazy Horse mountain currently in pro g ress in the Black Hills of South Dakota. The 56-minute video takes the viewer up the mountain for a behind-the-scenes look at the drilling and blasting crew at work on the mountain. The video was written, edited and produced by Robb D e Wall and is available exclusively from the Crazy Horse Memorial in both DVD and VHS formats. For i n f o rmation, see www.crazyhorsememorial.org The following, is a brief summary of the 25 steps involved in carving the mountain. The video goes into extensive detail on each of the 25 steps. Both those in the explosives industry and those outside the industry will find the video intere s t i n g .

Jan 1, 2004

By Sami Kara, Yunseok Park, Seung-Joong Lee, Namsun Hwang, Michael Laing

This study conducts a comparative analysis of construction efficiency. In the first part we compared electronic and non-electric initiation systems, focusing on tunnel contour holes. Field blasting operations were executed across a variety of delays to identify the optimal delay time. This delay for the in-situ rock mass was determined through regression analysis of blasting vibration in contour holes and for overbreak/underbreak. The blasting results with the electronic initiation system using the obtained optimal delay, applied to contour holes, were compared with the results of the non-electric initiation system. The overbreak and underbreak decreased by an average of 2.7 cm and 5.8 cm respectively, by using the electronic initiation system. Moreover, the vibration reduction rate in contour holes region was reduced by 11.9% based on the blasting vibration estimation equation proposed by the Ministry of Land, Infrastructure, and Transport (MOLIT). Underground construction projects have become increasing popular as cities grow in both size and density. This growth severely limits the amount of useable space for new project on the surface, resulting in the decision to build them underground. This new policy however brings into focus the challenge of managing and reducing blasting related vibration due to the proximity of these projects to sensitive structures, utilities and foundations often present in urban environments. For this purpose, we have been required to manage the vibration by reducing the quantity of explosives used per round. Inspired by surface blasting techniques, we applied a decking mode to address and work around this challenge. We present in this paper the first attempt to blast a tunnel face using a decking method and reduce the charging per hole from 6 kg to 3 kg per hole and keep the same advance rate for this tunnel. The results are presented in the third part of this paper. In the second part we present the results of the decking mode in shaft. The use of the electronic initiation system in tunnel construction provides the users an effective tool to improve the overbreak/underbreak and keep the vibration at a low level with a large gain on the overall project schedule and budget. This what we want to demonstrate in this paper.

Jan 21, 2025

There remains considerable controversy in the industry regarding precision type detonators and where the end user can benefit from their use. In spite of the fact that electronic detonators and other prototypes were tested over one decade ago, explosive suppliers have hedged on full scale production for many reasons. Although some of the reasons were based on solid economics, others were strongly influenced by shear internal resistance within the corporate objectives, ultimate fear of market rejection, indecision as to what degree of precision was required and limited data on defining the real benefits to the end user.

Jan 1, 1992

By Thomas Zukovich, Robert Morhard, Thomas Gelormino

The ExploTrack Explosives Tracking System is a sophisticated integration platform designed to track explosive products in both fixed locations and mobile environments globally, in real-time, on a 24/7 basis. The system utilizes active and passive RFID (Radio Frequency Identification Devices) installed within or applied upon explosives materials and explosives articles and incorporated within explosives packaging and logistic transport mechanisms. The system is designed for real-time inventory on an enterprise level and also across the globe providing explosives tracking, monitoring and explosives security from manufacturing throughout the logistics supply chain through use. The system can also track and monitor all known persons coming into contact with RFID enabled explosives materials and articles at the production level, at the magazine level, at the logistics level and to final use enabling a complete and real-time auditable chain-of-custody.

Jan 1, 2007

By Michael S. Wieland

"Toxic fumes cause fatal andnonfatal incidents in underground mining, where the working environment tends to trap the fumes, hindering the restoration of non-harmful conditions. Workers can underestimate the residual fume toxicity and return to the work site too quickly. The toxic fumes from charge explosions depend upon a number things: formulation ingredients, mixture uniformity, water resistance, hole contaminates, rock hardness, and dust interactions. Transitory hole-to-hole waves can cause partial desensitization, ruin the reaction kinetics, and worsen the fume toxicity.Traditionally the toxic fume hazard for a candidate explosive is resolved from a requisite tally of fume components. The resolution starts with the fume spectrum, a tabulation of specie concentrations, transformed to standard reference conditions and readjusted to remove the air dilution. The resultant influence, which is referred to as relative fume toxicity RFT, is deduced by a formula rule with some chosen constants and the requisite concentrations. The RFT result is normally compared to an RFT criterion that represents the worst-case (maximum) tolerable fume toxicity, as stipulated by regulations or otherwise."

Jan 1, 1997

By Travis A. Davidsavor, David A. Provost

A segment of high-pressure steel petroleum pipeline needed to be replaced on a hillside and beneath a waterway within an existing right-of-way containing multiple petroleum pipelines. The pipeline replacement required excavation of sedimentary rock to allow placement of the new pipe. As a result of an existing right-of-way limitation, steep slopes, and hard rock, blasting would be required as close as 7.8 meters (25 feet) from two operating pipelines.

Feb 1, 2020

By T Goswami

The conventional practice in open cut coal strip mining has been to blast the overburden or coal layers in separate blast events. This is done in order to maximise the benefits from throw blasting and also to limit coal losses. Each blast event usually has a particular design of hole diameters, burdens and spacings, explosive charges and blast timing in order to achieve the required blast outcome for either the overburden or coal. This means that each blast has to be separately cleaned on the surface after excavation of the previous blast. Hole locations then have to be individually surveyed and marked, holes drilled, explosives and initiators loaded and the blast fired. Each of these actions takes considerable time and resources and therefore impacts on mine productivity. The mine has to be cleared for each blast event and every blast presents a new potential source for noise, dust or vibration disturbance to the neighbouring population. Exposed highwalls are also subjected to vibration and damage from each subsequent blast event

Jan 1, 2006

By Jackson R. Pressley, Bruce Vandenberg

The knowledge of how and when your explosives go off can help you make intelligent decisions regarding future application of explosives thus removing some of the black magic associated with blasting. The net result will be intelligently set-up shots with timing, explosive charges, and placement more accurately done. Lower operational costs can be achieved when the correct combinations are applied.

Jan 1, 1992

By S. K. Chan, C. Badeen, S. Goldthorp, H. Feng, I. Alilovic, R. Turcotte

Over the last few decades, water-based explosives and their precursors, despite their apparent insensitivity, have been involved in a number of accidents around the world. A large proportion of these accidents occurred when these emulsions were pumped either for their manufacture, transport, or handling. In Canada, this has led to the development of “Guidelines for the Pumping of Water-Based Explosive”, which state that “using pumping pressures well below the laboratory measured minimum burning pressure (MBP) of the corresponding emulsions or watergels is a good safety practice”. However, in the above document, there is no description on how the MBP should be measured. In the last few years, a research program at the Canadian Explosives Research Laboratory (CERL) in collaboration with Orica has been focused on the development of a validated measurement protocol for realistic MBP measurements.

Jan 1, 2014

By Ruilin Yang

Blast vibration in the highwall from a cast blast in open pit mines or in the hanging walls from a stope blast in underground mines is a common concern. Vibration in such cases is a typical near-field situation where the distance from a blasthole to a point of interest varies significantly compared to the distance between the blast as a whole and the point of interest. Most existing blast vibration models are designed for far-field vibration using a single seed wave to represent all blastholes within a blast and do not simulate wave shape change over the distance. Using the site parameters from the analysis of signature hole vibrations, the present blast vibration model yields reasonable agreement with field measurements in terms of vibration amplitude and frequency. Case studies show that the model has been used successfully to assist field vibration control.

Jan 1, 2010

By Earl C. Hutchison, Wade C. Hutchison

T 0 effectively evaluate property damage that is claimed to have been caused by blasting activities and in order to lay the proper foundation to build the best legal defense, identification of the actual causation for the damages are necessary. For the past twenty years, engineering personnel from VCE, Inc. (previously Vibration Control Engineering, Inc.) have been evaluating claimed blasting damages with pre- and postblast inspections, with analysis of seismic levels, blasting amounts at given distances, and with other engineering considerations. In addition to these evaluations, they have also documented other causes for damages which are of the types that are often claimed as blasting damage.

Jan 1, 1995

By Nils Heinke, Stephen M. Collinsorth

To anyone who is responsible for the production of blast holes, who is looked to on a daily basis for drill maintenance and performance, whose bottom line may depend on the survival of the mine itself.. How much awareness should one have on such things that truly impact production, maintenance and overall job cost? Do you know your drill’s maximum capacity?

Jan 1, 1998

By Travis Davidsavor, David Provost

A segment of high-pressure steel petroleum pipeline needed to be replaced on a hillside and beneath a waterway within an existing right-of-way containing multiple petroleum pipelines. The pipeline replacement required excavation of sedimentary rock to allow placement of the new pipe. As a result of an existing right-of-way limitation, steep slopes, and hard rock, blasting would be required as close as 7.8 meters (25 feet) from two operating pipelines. Existing pipeline company standards would have effectively precluded the construction of the replacement pipe by blasting rock. To facilitate the required construction and evaluate actual pipe stress during blasting to ensure pipeline integrity, a comprehensive evaluation methodology was developed by a team of pipeline, mechanical, geotechnical, instrumentation, and blasting engineers. A total of 60 strain gages were affixed to the steel pipe and seismographs were buried at the surface near the blasting area. Test blasting allowed pipe stresses with corresponding ground motion to be monitored. A conservative analysis approach evaluated individual peak strains and revealed that only small pipeline strains, and therefore stresses, were induced in the pipeline as a result of blasting. This evaluation allowed specific procedures to be developed to inform the blasting operation of maximum explosive loading and minimum charge distances. Additionally, this effort provided the pipeline operator with appropriate pipeline operating pressures during blasting activities to limit total stresses in the pipeline to be below allowable stresses imposed by code, regulators, and company operational limitations. Recommendations were developed to measure the blast generated ground vibrations with seismographs buried at the depth of the pipe, near the pipe, and limit the ground vibrations from blasting to 150 mm/s (6 in/s). If ground vibration intensities of 120 mm/s (4 in/s) or more were observed, additional engineering review is recommended. Finally, all blasting would be suspended and all activities reviewed at peak ground vibration intensities of 230 mm/s (9 in/s). The evaluation effort resulted in effective and efficient construction of the pipeline replacement and allowed the pipeline operator to better understand blasting induced stresses on their assets.

By Troy Williams, Chris Preston, Ian Lipchak

"Underground blasting operations are challenging from the standpoint of the distribution of explosivesenergy representative of ring blasting. Energy from both shock and pressure regimes of commercialexplosives may appear concentrated in the collar region of a typical ring blast and diluted at the toes of holes due to the oblique geometries of blastholes. The non-homogenous nature of ore in whichexplosives are distributed via drillholes, adds to the complexities of generating particulate profiles from fragmented material with consistencies that are predictable from blast pattern to blast pattern - well suited for specific underground handling equipment and mill processing. In an ideal world, it would be the blasting operations themselves that represent the primary crushing mechanism, or at least mitigate mechanical crushing that can comprise a large component of the cost in generating suitable muck. This paper presents a dynamic break view in 3D that allows a planner to visualize the potential break zone around a blasthole generated by an explosive load using a Kleine field. Simple as it sounds, this methodology provides information that can be used in conjunction with cavity monitoring surveys (CMS) to potentially judge dilution due to overbreak as well as recovery for a typical blast. As examples, there are two break geometries that are examined regarding circular breaks and elliptical breaks around blastholes. Using a Kleine field to define break, a planner generated isosurface can be generated and compared to CMS data for calibration and prediction, using AEGIS 3D ring design software."

Jan 1, 2016

By Brent Blanchard

Dallas/Fort Worth Airport recently took a major step in its fiveyear expansion project with the explosive demolition of the Hyatt Regency Hotel West. Built in 1965, the Hyatt Regency held the distinction of hosting five U.S. Presidents over the years and was reportedly one of the first hotels in the world to be built within an airport’s boundaries.

Jan 1, 2003

By John Babcock, Gregory Poole, Ron Hudson

In January 2007, Fultondale Alabama opened a new elementary school. Site work at the old school location included blasting activities and the old school building was scheduled for demolition. With help from Apache Construction, blasting was scheduled to be performed in close proximity to the old school building prior to the demolition. Arrangements were made to perform extensive monitoring on the old school building during the blasting activities. The monitoring plan for the project included: • Pre and post blast inspections were performed on the structure; • Conventional crack monitors were installed at 22 locations throughout the structure; • Digital displacement monitors were installed at 6 locations on the structure; and • Seismographs were used to monitor structure vibration at 6 locations and ground vibrations at 9 locations. Blasting activities were allowed to produce vibration levels well above the safe levels established by the U.S. Bureau of Mines (USBM). Vibration levels up to 7.44 in/sec were recorded with no damage noted. Permanent deformation was recorded on vibration levels of 9.68 and above. Not only did this project reinforce previous studies which indicate that concrete block walls can withstand vibration levels well above 2.0 in/sec, this study was also a good example of employing new technology to help determine if/when damage occurs on a specific structure.

Jan 1, 2009

By Gerald W. Longenecker

For decades, traditional hydraulic engineering approaches have been used for sizing stream channels when stream relocation efforts have been necessary to allow for the advancement of quarry and other surface mining operations. These approaches have been based on various ydraulic models to design channel cross sections and slopes that could pass the required regulatory design storm such as the 2-, 5, lo-, 25-, 50-, or even loo-year events. Designing the stream channel to handle these more extreme ,storm events would often lead to large channel designs which required extensive bank and channel bottom stabilization techniques including concrete, rip rap, gabions, or other expensive approaches. The constructed channels often required ongoing maintenance to remove accumulated sediment and other debris which would settle out and reduce the hydraulic capacity of the channel.

Jan 1, 1998

By Kyle Wagner, William Joa, Colter Angell, Catherine Johnson, Marty Langenderfer, David Doucet

The goal of any business is to seek the maximum profitability for the organization through optimization the use of resources, processes and the application of new technologies. An analysis of various case studies demonstrate that blasting can have positive impacts on the crushing and milling processes resulting in increased profitability for the mining industry (Grundstrom, Kanchibotla, Jankovich & Thornton, 2001). This paper describes the case study of two copper mines in Peru producing Cu-Mo and Cu-Au concentrates, which together with their strategic partner, have implemented a project focused on the improvement of rock fragmentation. The project was based on techniques of pattern size reduction, the use of high energy explosives and the technology of electronic initiation. Combined, these techniques were shown to have significantly impacted the efficiency of downstream processes.

Jan 1, 2019

By Daniel Hauer

Blocking. (5) The “blocking” of boulders is a much cheaper way of breaking them up than “mud capping.” It should always be used in preference to that method except when too much time will be consumed by a crew of men waiting for the drilling to be done, as shown in example of cost No. 1, as given under “mud capping.” Under such circumstances the time consumed would be a greater cost to the contractor than the extra amount of dynamite. Then, too, on large thin boulders to drill one hole would result only in breaking the stone into such pieces as would again have to be broken; and the many holes might equal the cost of extra dynamite. Under such circumstances if method (6) cannot be used, “mud capping” will have to be resorted to, to do the work economically.

Jan 1, 2006

By Shonn K. McNeill, Joshua Micah Hoffman

Security engineering is similar to other forms of engineering – the design is guided by the loads, materials, and desired function. For facility design, the load is the threat. Facilities that are designed with considerations for explosive hazards are designed with a shot, or series of shots, of a given size and distance from key locations. These facilities range from office buildings and industrial sites in developed nations to military and police stations in contingency areas. The challenge is the design shots are not often communicated to facility owners and managers. If the hazards change, whether it’s due to an increased capacity to cause damage by a threat or a decrease in capacity by a structure, not knowing the design shot means not knowing if security design needs to change. Blast modeling is an engineering tool that can be used to reverse engineer what a facility is suitable for, as well as be a tool for modifying security design for new conditions. This paper will examine military and civilian examples, including a case study of a military facility that did not know their as-built conditions and had to be rapidly closed; due to the determination their security engineering shortcomings could not be mitigated.

Jan 1, 2019