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By Michael Mann, Kenneth K. Eltschlager

The International Society of Explosives Engineers (ISEE) Standards Committee has recently updated both the Field Practice Guidelines for Blasting Seismographs and the Performance Specifications for Blasting Seismographs. The revisions are the result of public and industry input along with recommendations of the ISEE Blast Vibration and Seismograph Section. The committee is comprised of blasting seismograph manufacturers, users and general interest personnel. On an as needed basis, subject matter experts are enlisted to advise the committee. Three phases of activities are necessary for each revision cycle: request for comment on the existing standard, first draft revision of the standard based on public input, and final draft approval by the ISEE Board of Directors. The ISEE standards revision process will be explained and each standard will be discussed along with the significant revisions from the latest revision cycle.

Jan 1, 2018

By Pat McLaughlin

Blast design in the construction industry has often been based on past practice or powder factors. This is to some extent understandable, since construction projects do not have the longevity of mining or quarrying operations and therefore have less opportunity to pursue potential improvements. The main concern of the operator is whether or not the technique will work, and at what cost to the downstream processes. Time, not long term savings, is of the essence.

Jan 1, 1994

By Jonathan Peck, Doug Pollitt, Malcolm Scoble

Over the past 5 years the Department of Mining and Metallurgical Engineering, McGill University, has been involved in the performance monitoring of both percussive and rotary drills. Studies conducted in open pit coal and iron ore mines using microprocessor-based research and commercially available instrumentation resulted in the monitoring of at least 6 performance parameters while drilling vertical production blastholes.

Jan 1, 1991

By R. Franfield

This paper describes a situation that many drilling and blasting contractors have found themselves in – a client?s fear of the use of explosives. In the summer of 2007 Blasting Services Ltd was asked to undertake some drilling and blasting work in an abandoned quarry that was being restored for a housing development. Previous quarrying operations had left a series of overhangs that were considered unsafe and required removing. The site contractor considered that the best and safest way to carry out this work was by drilling and blasting. Blasting Services Ltd, with the technical assistance of Exchem Explosives, designed a drilling and blasting regime to accomplish this work with a series of trim blasts. The design took into account the close proximity of a structure in very poor condition and the imposed vibration limit of 6.0 mm/s (0.24 i.p.s.). The faces were profiled, holes drilled and explosives ordered. A few days before the first blast was due to be carried out the client decided that the poor condition of the nearby structure meant that the use of explosives could not be permitted. This decision was made despite the blast design indicating that the vibration level would be well below the 6.0 mm/s (0.24 i.p.s.) limit.

Jan 1, 2009

By Kevin Phelps, Jason Baird

When dealing with high velocity projectiles, the ability for researchers to accurately and precisely measure the velocity of the projectile is of great value. This report will analyze three different methods of recording high velocity projectiles for: their ability to record velocity data, pros and cons for each method, and any possible bias or limitations that would result. Method 1 uses a Phantom V10 high-speed video camera and a velocity reference screen to record the projectile’s path and proprietary Phantom software to analyze the data and determine velocity. Method 2 utilizes two break screens. This method, consisting of strung copper wire as the break material, is one that has been used in the past by Missouri University of Science and Technology (MS&T) researchers in assisting in finding velocities of high-speed projectiles. Method 3 is a pair of make screens, similar to Method 2 in that two screens were used for each test but relies on a projectile making a circuit between two sheets of metal separated by an insulation layer, to find a velocity. All three methods will be used simultaneously in each shot to rule out any projectile differences in subsequent shots. Projectiles of three different relative velocities, low, medium, and high, will be fired and analyzed to determine strengths and weaknesses of each method.

Jan 1, 2014

By Randall S. Marks

Bonneville Dam, completed in 1938, included the smallest and busiest lock on the Columbia and Snake River Navigation System. To expedite barge traffic through this restriction, a new larger lock was designed and contracted by the U.S. Army Corp of Engineers.

Jan 1, 1997

By Lars Arne Granlund

Due to the coarse structure of mining explosives, one has to model a finite reaction zone,contrary to C-J calculations, describing their detonations, i.e they become dependent of diameter and confinement, An effort within the DYNO group has been to investigate if the DSD theory ( originally developed by Bdzil, Stewart / Los Alamos ) can be used to describe major groups of civil explosives.The groups of explosives tested are dynamite, anfo, aluminised emulsion, heavy anfo and straight emulsions.

Jan 1, 1995

By William H. Highlands

Lightning is a natural phenomenon which poses a potential hazard to people, structures, and equipment unless adequate protection is provided. The type of protection required is related to the nature and of the facility. The decision making process involves a number of interrelated factors which should be considered when determining the need for protection.

Jan 1, 1989

By Scott Orenstein

Construction blasting has allegedly been the cause of property damage in the following situations: (1) When the detonation of the shot hurls rock and debris into the air that causes property damage upon impact; and (2) When property owners notice cracks in their walls and foundations after they experience the momentary vibrations that coincide with the detonation of the shot. The current state of the law for both these situations is firmly established. Blasting is classified as an abnormally dangerous activity, for which the blaster is held strictly liable, whether the damage is the result of flying debris or vibrations and concussions generated by the blast. It is when the alleged blasting damage is supposedly from concussions and vibrations, however, that the courts usually reach the wrong result. The typical scenario involves property owners that thoroughly investigate their property after feeling blast generated vibrations, and find cracks that they believe did not exist beforehand. Most often the truth is that the property owners have never noticed these cracks before because they have never looked that closely before. Any structure has a certain number of cracks due to a variety of causes, such as settlement overtime and temperature and humidity changes.

Jan 1, 2004

By H. Venkatesh, Balachander R.

This article discusses the method that was adopted for controlling damage to rock mass while excavating an underground powerhouse cavern at Tala Hydroelectric Project. It discusses in detail the near field vibration studies carried out and the safe vibration levels established for that rock mass condition.

Jan 1, 2006

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 David G. Borg, John Bussey

The new AIRDEK (tm) technique for pre-splitting in surface coal mines produces highwall conditions that have greater safety with lower costs for explosives, labor, and drilling. Successful applications have been made in highwalls ranging from 20 to 100 feet or more and in blasthole diameters from 3-1/2 inches to 12 inches.

Jan 1, 1988

By Agne Rustan

The 9th International Symposium on Rock Fragmentation by Blasting was held in the Granada Conference Centre, Granada, Spain from the 14th - 17th September 2009. The Symposium was preceded by a 1 ½ day Workshop on “Vibrations from Blasting” organized by the initiator Dr. Alex Spathis and his colleague M. J. Noy, both employed at Orica Mining, Australia. Prof. Josè Sanchidrian at the “Universidad Politécnic de Madrid” in Madrid, Spain was the main organizer for both the Workshop and the Symposium. A record number of participants came (292) from a record number of countries (41). There were a total of 14 papers in the Vibrations from Blasting Seminar and 96 papers and 2 Keynote Addresses in the Fragblast 9 Symposium itself. The aim with this paper is to present some results from Fragblast 9 which are of interest for a large target group. One very important result from the Fragblast 9 meeting was that it was decided there that Fragblast 10 will be held in November 2012 New Delhi India.

Jan 1, 2009

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

Laboratory experiments show that the delay detonators, either electric (copper coated or aluminium) or non-electric (down-the-hole) as generally used in opencast mines and quarries have some scattering from the actual firing time due to manufacturing inaccuracy and variations in basic ingredients of the product. This scattering varies from 1 to 4 % depending on the product quality. Due to this component scatter, adverse blasting effects like misfires, overbreak, underbreak or fly-rock may occur if the design patterns are not judiciously made. It has also direct impact on muck profile and fragmentation.

Jan 1, 1999

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 Douglas Rudenko

Most engineers, mine operators, or contractors acknowledge the importance of having accurate subsurface information in order to plan a project or solve a problem. Conventional methods of exploring the subsurface such as augering, core borings, or test pits can provide information, but it is often costly and sparse. Geophysical methods offer an alternative to help supplement sparse information~ gathered through conventional exploration techniques.

Jan 1, 1998

By Ron Frye, Carl Liibbe, Wayne Curtis, Julie Pecori, Dan Leach

Test work comparing the performance of a Low Density Porous Ammonium Nitrate Prill to regular Porous Ammonium Nitrate conducted in Pennsylvania and New York showed that less ammonium nitrate was required to perform the same work and that improved sensitization of an emulsion/ammonium nitrate blend reduced “orange fumes”. Fragmentation was similar in all tests with improved heave and throw experienced.

Jan 1, 1997

By John Brulia

You’ve probably heard the old expression, “The more things change, the more they stay the same.” But the adage doesn’t seem to hold much water when it comes to making a telephone call on the road. Thirty years ago, a “powder hound” had to stop his 2-wheel drive vehicle at either a roadside diner or a telephone booth to make a call using a public telephone. But, fast-forward to 2007, and a contemporary “explosives engineer” driving his or her 4-wheel drive vehicle simply makes a call “on-the-fly.” The fundamental difference between these two eras is the result of the introduction and the proliferation of cellular or wireless technology. On the one hand, this fundamental difference is much welcomed in the form of personal and business conveniences; and improved productivity. On the other hand, this fundamental difference creates a new set of un-welcomed conditions causing a potential “digital danger.”

Jan 1, 2008

By Cathy Aimone-Martin, Robert Brentar, Brent Meins, James Lauer

Vibration measurements of multi-story structures in an urban environment began 3 years ago in New York City during close-in blasting to adopt correct measurement procedures and recommend revised ground vibration limits that best characterize cracking potential in mid- to high-rise structures. Two broad categories of structures included non-engineered 4- to 6-story multi-family unreinforced brick masonry buildings, built from the late 1800s to around 1930, and post-WWII, high-rise structures of reinforced concrete and steel rising 12 to 40 stories. In-ground vibration limits similar to those recommended by the U.S. Bureau of Mines safe criteria, developed for 1- and 2-story residential structures, are imposed by the New York City Fire Code. However, these limits are often lowered by project engineers or New York Department of Buildings when blasting is planned near buildings designated Landmark or historic and classified as fragile or vibration-sensitive. Seismograph measurements to determine compliance with in-ground velocity limits currently employ geophones mounted to basement walls and on concrete slabs overlying rock. These measurements cannot be correlated with upper structure cracking potential and are often exceeded, resulting in excessive and costly downtime to allow post-blast damage investigations.

Jan 1, 2014