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By Larry Schneider

In recent years, many individuals looking into the future of the blasting industry have predicted that the most likely next technological breakthrough would be the use of high precision, digitally controlled detonators. This seemed logical since not only was there much room for improvement in this area, but any significant improvement in delay timing could yield great benefits in productivity and control of adverse effects. And in fact, within the past two or three years, such electronic detonators have been introduced in the field by a number of different manufacturers. These systems are currently being used in many routine blasting operations around the world which are being closely watched and evaluated.

Jan 1, 2006

I attended a funeral in West Monroe, Louisiana, for one of the best powder peddlers I’ve ever known. He started work in 1948 for Dixie Dynamite, a seismograph explosive distributor. His first job was as a truck driver, then magazine keeper and then sales re p re s e n t a t i v e . When Dixie Dynamite quit, he acted as an explosives sales agent for sometime before moving on to Kansas to be a sales rep for a distributor there. We called him the “ragin cajun” long before James Carville came on the national scene messing up things. While he was born in G e o rgia, he was a Cajun at heart. I don’t believe the old saying, “Build a better mousetrap and the world will beat a path to your door.” To me, the best products in the world need to be sold. Two examples of this are the Beta system for TV and the Apple Macintosh computers. Beta is the best system but VHS took over because the Beta people fell down on the selling job. Windows 98 is Macintosh ‘86 but again the engineers were not salesmen. Marion “Johnny” Johnson who was buried only about a half mile from his first magazine site proved that good selling is good citizenship. He could have sold any firstclass product, for he wouldn’t tolerate inferior items, and made a successful career of it, but he chose dynamite and the industry benefited from his talents.

Jan 1, 2004

By Rodney D. Lamond

The need for blast vibration monitoring can be attributed to a combination of three factors: Structural damage, Blast design and Human annoyance. Traditionally, vibration damage criteria are prescribed in terms of peak particle velocity (PPV), as measured or predicted in the ground surrounding a blast. The PPV in the vicinity of a blasthole is strongly influenced by the quantity of the explosive per delay. In general, the existing prediction models give reliable results but fall short of addressing the change in PPV when the charge is decoupled and/or distributed.

Jan 1, 1995

By J Aydin Bilgin, Sedat Esen

This paper describes the ideality of some commercial explosives with the help of the detonation theory and detonation velocity measurement. Ideality of an explosive can be determined by comparing experimentally measured and ideal detonation velocities. A measured detonation velocity at a certain charge diameter markedly lower than the ideal value indicates incomplete reaction and thus non-ideal detonation. Since it is shown that commercial explosives exhibit non-ideal behavior, two-dimensional detonation theory should be used to evaluate the performance of explosives. This theory enables to compute the detonation properties of explosives (detonation velocity, detonation pressure, etc.) as a function of charge diameter and confinement. The use of the one-dimensional detonation theory to compute the detonation properties for commercial explosives has an error associated with it as these calculated properties are independent of charge diameter and confinement. It assumes that shock front is planar. Hence, it is incapable of assessing the ideality of the explosives due to its assumptions. Shock front in real situation is curved in shape but not planar as in one-dimensional detonation theory. In this paper, the non-ideal behavior of some commercial explosives is modeled using EXRINT code based on the steady-state two-dimensional detonation theory firstly. Then the degree of ideality of each explosive found from the code is checked using detonation velocity test results conducted at a quarry. It has been shown that idealities of the tested explosives determined by the code agree well with the field detonation velocity test results.

Jan 1, 1999

By C. Navalkar

Systematic drilling & blasting techniques are currently being viewed in the mining & construction industry as a correct 8z scientific approach for optimization process in rock excavation, as drill & blast costs usually represent major share in total cost of production and also the environmental impacts plays an important role in designing of the operations. Designing a blast is a complex planning task, which for optimization, includes deciding the bench geometry with respect to the rock properties & geology of the area, capacity of the excavators, choice of explosives & detonation method, tiring sequence, etc. Optimization of blast design needs a detailed comprehensive study of all the above intersecting elements. Preblast & Post blast surveys are required for further improvements in blast designs. However, the choice of blast design depends upon the the requisite blasting results opted for and the cost you are ready to pay for the same. The blasting operation, in general, also involves numerous side effects namely, ground vibrations, fly rocks, dust, noise & gas pollution, air blast effect etc. Again these effects can be made tolerable up to a certain extent depending upon the limitations of the environmental obligations as may be specified by the concerned authorities.

Jan 1, 2001

By Ray Patterson

A planned modification to a cement kiln at the Holnam Portland Cement Plant near Florence, Colorado required the removal of a ring of cast-in-place (CIP) refractory lining. The CIP lining was approximately 14 inches wide, 12 inches thick and 38 feet in circumference.

Jan 1, 1999

By L. Trivino

Blast-induced damage criterion based on the peak particle velocity has worked reasonably well for estimating building damage. However, the same criterion cannot be used to estimate damage to rock and mine structures such as shaft and tunnel walls. It does not take into account the nature of seismic radiation pattern in the near-field, which is very different than what is obtained at far-off distances. To investigate this phenomenon, a systematic study has been carried out involving single-hole blasts and normal production blasts, with explosive source ranging from nearly point source charges to standard borehole sizes (6-7 m long explosive column), with charge weight varying from 0.5 kg to 30 kg. In the near-field, it is shown that, both P-wave and S-wave take a dominant position compared to the mainly surface waves measured in the far-field. These are shown to depend strongly not only on the length of the explosive column but also the way it is initiated in the borehole (i.e. direct vs. reverse initiation in the borehole) with respect to the target location. The seismic radiation patterns were recorded by high-frequency triaxial accelerometer stations grouted in the rock mass. This study describes the nature of seismic radiation in the near-field from long and short charges, the role of initiation direction and their effect on frequency with respect to sensor locations or target area of interest, and their implication in prediction of blast-induced damage in the near field.

Jan 1, 2009

By Steve Dillingham

In every aspect of conduct, on the blast site or off, the issue of credibility is raised. Promises are made, commitments are satisfied, safe practices are obeyed, communication is maintained, and proven procedures followed. Only by fulfilling these objectives, are we deemed trustworthy and reliable - in other words - credible. Unfortunately, at times, we fall short of achieving our goals. Whether intentionally or accidentally, everything is not completed according to plan or accuracy. On the blast site, falling short of achieving such goals may contribute significantly to a chain of events that can potentially produce accidents. At the very least, a blaster’s credibility will be jeopardized. The fact remains that the blaster that continuously conducts business in a professional manner will less likely find him or herself as a defendant in future claims.

Jan 1, 2003

By Zvonimir Ester

The course of motorway tunnel under construction was set only 2 m away from the main motorway. The thickness of the tunnel overburden rock was 9 m. During the tunnel construction the traffic on the motorway was not supposed to be interrupted. The tunneling was carried out by NATM with classical drilling of blastholes and by blasting.

Jan 1, 1998

By Kate Satish

M/s Konkan Railways Corporation are constructing 760 kms long rail road in the Western Coastal Region of India. The rail road encounters 75 tunnels through the Western Ghats of India with a total length of 78.35 kms, the longest tunnel being 6.5 kms long. The tunnels are of horse shoes shape having a cross section of about 37 Sq.meters

Jan 1, 1996

By Joseph Haid, om, Rio Yang, Kelly Fleetwood

Some coal mining operations in the Powder River Basin are currently observing a number of blast holes detonating sympathetically within their cast blasts. Sympathetic detonation can cause poor cast results, high blast vibration levels, excessive back break and fly rock, along with a number of other undesirable blast results. The reduction or the total elimination of blast hole sympathetic detonation is of paramount importance to the coal mining companies operating in the Powder River Basin. This paper describes a systematic approach to prevent cast blast holes from detonating sympathetically through the use of the electronic initiation and expanded blast patterns. In-situ measurements outlined in this paper were recorded from pressure probes, velocity of detonation probes and near field accelerometers, along with digital images generated from a high speed CCD camera. Large diameter angled drill holes were also checked for any measurable amount of deviation by a cable type borehole measurement tool. The field measurements provided the scientific evidence, statistical data, and documentation necessary to develop a sound method or a “road map” that would minimize and in some situations prevent the occurrence of blast hole sympathetic detonation.

Jan 1, 2005

By Fumihiko Sumiya, Kunihisa Katsuyama, Yuji Ogata, Yuji Wada, Yukio Katoh, Yoshikazu Hirosaki

In our previous work, the results of photographic observation using a high speed framing camera showed that the difference between precursor air shock wave velocity and detonation velocity was primary factor for the channel effect. It is assumed that the decreasing precursor air shock wave velocity can prevent the channel effect in charge hole.

Jan 1, 1996

By John A. Davis, David W. Brunton

(Excerpts, pp 157-160) The usual means of firing blasting charges, especially in tunnels and adits in the Western States, is by the use of a safety fuse. The term safety fuse originated from the fact that when properly used under working conditions this fuse burns at a uniform rate and does not flash or explode, as was often the case with the means employed for igniting blasting charges previous to its invention; but the term is somewhat misleading, because the fuse is not, nor has it ever seriously been claimed to be, safe for use in gaseous coal mines. The fuse used for tunnel work is composed of a core of gunpowder surrounded by various layers of waterproofing material.

Jan 1, 2015

By Paul Downing

Anyone in business today knows how difficult and time consuming it is to keep abreast of new and revised federal regulations. Those in the explosives industry know that such a task can be next to impossible as the regulatory environment faced by those in the hazardous materials community continues to undergo a major overhaul following the events of September 11th, 2001. This paper will attempt to clarify today’s regulatory picture by identifying some of the regulatory “hotspots” and “pitfalls” that affect individuals and companies involved in the sale, transportation, distribution and use of explosives.

Jan 1, 2003

By Jeff Peterson, Alastair Grogan

During the winter of 2001/2002, a number of seismic exploration projects were carried out in the Mackenzie River Delta area of the Northwest Territories, in Canada. The purpose of the seismic projects was to identify potential drilling targets for subsequent drilling programs, using explosives as a seismic source. Recent changes to fisheries regulations meant that blasting under lakes, the Mackenzie River and offshore from the delta, was not allowed to induce water overpressures in excess of 100 kPa in these water bodies, and that a water overpressure monitoring program had to be conducted to confirm that this requirement was being met. This paper describes the water overpressure monitoring program on one of the exploration projects, presents the results of the monitoring, and discusses the challenges of carrying out this work in the middle of an arctic winter.

Jan 1, 2003

By Thierry Bernard, Pierre M. Vuillaume, Michel Kiszlo

"In the context of its studies for the trench ministry of the environment and for the French national coal board, INERIS (the French institute for the industrial environment and hazards, formerly CERCHAR) has made a complete critical survey of the methods generally used to reduce the levels of blastingvibrations."

Jan 1, 1996

By Don Z. Painter, Gordon F. Revey

Frontier/Traylor Joint Venture is presently constructing a section of the Tri-County Metropolitan Transit District of Oregon's (TRI-MET) Westside Light Rail system. This new section will extend Portland's existing transit system to the western suburbs of Beaverton and Hillsboro. The drill-blast excavations at this project include 10,000 feet of 20 foot tunnel, 18 cross passages, three shafts, an underground railway station, and a U-wall open cut. From a blast designer's perspective, this job has been extremely challenging. Blast vibration is limited to 0.5 ips at 200 feet or at the nearest structure, and airblast is limited to 129 dB -- linear peak and 96 dB -- C scale. The tunnels pass under heavily built up areas and have top of tunnel to surface cover distances as low as 70 feet. Surface blasting in the 26,000 cubic yard U-wall excavation was limited to five short nighttime periods due to its proximity to the very busy highway 26.

Jan 1, 1995

By Steve Dillingham

The horrific events surrounding September 11th left Americans with a feeling of sudden helplessness...the shock of being unprepared and powerless. From this tragedy, we can understand the need to prepare for the unexpected, and can apply this hard lesson into operational planning for those involved in the commercical explosives industry.

Jan 1, 2003

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 A T. Spathis, M G. Wheatly

Some preliminary dynamic pressure data were obtained from several charges detonated in a tunnel situated in massive granite rock. The context of the work is the potential for desensitisation of explosives, failure of detonators, and sympathetic detonation due to the close proximity of inter-hole and inter-deck explosive charges to each other. Dynamic pressures were measured using piezoelectric gauges in water-filled 45 mm diameter holes adjacent to the charges. Some of the first arrival peak pressures were noisy, and although not fully resolved, may be due to reflections and the physical arrangement of the transducers and their size with respect to the monitoring holes. The estimated peak pressures were between 0.1 to 8.7 MPa at approximate distances of 2.8 to 0.8 m, respectively. Further work is planned with gauges that are disposable, have a higher pressure range, and can be used within a few borehole diameters rather than the piezoelectric gauges used in the present work.

Jan 1, 2016