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By C. Liley

Open cut blasting at the Ernest Henry mine has the potential to cause damage to nearby underground workings. This paper is a case study of the blast vibration management project which was conducted to ensure pit blasting did not adversely affect the stability of upper production levels or cause damage to the underground primary fan units.

Jan 1, 2012

By Calvin Konya, Anthony Konya

Presplitting is a form of blasting that when executed properly will create a smooth wall that will minimize secondary conditioning. In recent years, presplitting has become a popular technique to be used in both the mining and construction industries, however, presplitting fails on many occasions because of ‘geologic conditions’. This is typically because of improper explosive loads consisting of overloading and underloading blastholes. In this paper the authors introduce new factors such as a presplit factor which varies for different rock types, selection criteria for the spacing of presplits, and the optimization of explosive load for the technique of Precision Presplitting.

Jan 1, 2017

By J. Eloranta

"Previous work indicated that the annual per-capita consumption of raw aggregate material averages about 10 tons; half of which is produced by blasting. Given a population of approximately 320 million in the United States alone, this amounts to 1.6 billion tons of blasted material annually. It was also estimated that up to 20% of the blasted material in aggregate operations is smaller than 6.35 mm (1/4inch) in size. Thus, about 320 million tons (i.e. 1 ton per capita) of byproduct is produced annually and sold at significantly lower prices or potentially discarded in waste dumps."

Jan 1, 2017

By Timothy D. Stark

Blasters are usually strictly liable for injury or damage caused by flyrock (trespassory invasion) and blast-induced vibrations (non-trespassory invasion). The application of strict liability to non-trespassory invasions has resulted in significant litigation that has hampered the use of blasting and the blasting industry. Stark (2002) proposes that blasters should not be held strictly liable for non-trespassory invasions but should be liable only if their conduct is proven to be negligent. This change in legal standard was proposed because improvements in blasting technology over the last thirty years allow blasting to be conducted without substantial risk of harm to property and thus the amount of harm imposed by a blast can be related to the level of care exercised by the blaster. It is anticipated that negligence standard will reduce the amount of litigation because a plaintiff will have a greater burden to overcome. To facilitate the acceptance of negligence standard by a court of law, this paper illustrates the application of the negligence and strict tort liability frameworks using actual cases in which a decision was rendered. It is evident from these cases that some of the successful claims under the strict liability framework would not have been successful, and probably not litigated, under a negligence framework, which could result in substantial cost savings to the blasting industry and consumers.

Jan 1, 2004

By C W. "Mickey" Bradley

Thunder strikes terror in the hearts of man and has since the advent of time. We all fear the unknown; even the Greeks created a god, THOR, to be responsible for the thunder and rain. Thunder, by itself, can't hurt anyone; it is simply hot air moving very fast. Thunder, however, is caused by lightning and lightning is what we need to fear and rightfully so. Annually, lightning kills hundreds of Americans, injures another 2,000, damages or destroys approximately 30,000 structures, 1 starts thousands of forest fires and strikes mine properties over 100,000 times.

Jan 1, 1992

By Charles L. Greening

MARTIN MARIETTA CEMENT at Martinsburg, West Virginia, has been and presently is engaged in coupling present open pit with old underground workings. Various drilling and blasting techniques have been introduced in an endeavor to achieve optimum results. This paper will relate to three roof shots at Martinsburg, one of which realized a controlled blast of 248,000 tons of material.

Jan 1, 1982

By Alexander S. Escalante, Luis R. Ramirez, Nelson A. Arostegui

Research, analyze, discuss, design, and build an electric oven to perform one of the quality control tests the fanel or common fulminers to determine what temperatures they can detonate at. Give practical applications, conclusions, recommendations and bibliography.

Feb 1, 2020

By William. J. Birch, Catherine. E. Johnson, Robert Farnfield

Rocks and other materials can be characterized by their elastic properties. However, seismic velocities represent a more practical set of physical properties for seismic methods. Seismic velocities define the speed at which various elastic deformations propagate through different rock types. Seismic velocities for a given material can be expressed explicitly in terms of their elastic properties. It is widely accepted that the peak particle velocity and associated frequency of ground motion are important parameters for determining a safety criterion to minimise the potential for both damage to structures as well as nuisance to people. Whilst the key considerations are the blast design parameters, the seismic velocity is important as particle velocity is dependent in part on the powder factor [blasting ratio] which in turn is found to be dependent on the seismic velocity.

Feb 6, 2023

By Scott Gustfason, Richard N. Snyder

What is a safe stand-off distance? Recent mishaps using conventional blasting equipment have seen flyrock as distant as 3,750 feet from the blast area, or close to three-quarters of a mile, therefore, whether below ground, under water, in surface quarries or at a structural demolition site, data signals riding a radio wave promise a new horizon for the users of both electric and non electric blasting circuits.

Jan 1, 1987

By Leslie Taylor, Kevin Genson

This paper reports on an experimental study of the effect that bottom shaping might have on the impulse delivered to a light armored vehicle due to a buried mine detonating beneath the center of it. The study was restricted to explosives buried in saturated sand and three parameters were varied within the study: bottom angle (0 degrees to 21 degrees), depth of burial of the explosive (1.02 mm to 12.7 mm), and stand off distance (0 mm to 38.1 mm). Six hundred and thirty six milligrams of explosive was used as the explosive load. It has been shown in previously published work [1,2] that Hopkinson scaling works well for the determination of impulse loading on a semi-rigid target plates. Therefore in terms of a full scale test using 4.54 Kilograms of explosive the parameters investigated would cover a DOB of from 19.56 mm to 243.84 mm and a Stand off distance from 0 to 734.06 millimeters. These values nicely cover those of interest to the Marines with regard to the AAV (amphibious assault vehicle). Four angles were investigated at all DOB’s and Stand off distances – 0 degrees, 7 degrees, 13 degrees, and 20 degrees. The results show that reduction in impulse delivered to the target is achieved with an angled bottom on the target plate with a major reduction occurring before the 13 degree angle is reached. Hence vehicles with quite modest bottom angles could help greatly in load reduction with very little loss in utility.

Jan 1, 2008

By Alejandro Berrios, Matheus DaSilva, Erick Siqueira

Vazante mine is an underground polymetallic mine that produces zinc, lead, and silver, which belongs to Nexa Resources in Minas Gerais, Brazil. The mine, a sublevel stope underground mine, mainly applies two subvariants: VRM – Vertical Retreat Mining and Open Stope. In a specific place of the mine, the geology allowed the design of a production stope with larger dimensions than the standard stopes, commonly called Super Stope. At this place, the plan was to apply both sublevel variants simultaneously. This mining block comprises rings in two different levels, with access by two ore drives on each level; the dimensions would be approximately 50 meters high, 50 meters long, and 35 meters wide. Opening the Free Face to mine the whole Stope was a challenge due to operational issues, such as hazard risks from loading over void space, exposure to uncontained places, and the impossibility of implementing the optimal blast sequence. Wireless blasting initiators have gained popularity recently due to their convenience, safety, and efficiency. This initiation system was applied to preload all the rings required to open the Free Face, ensuring a safe and optimal blast sequence. Wireless initiation prevented hazard risks, enhanced the blast sequence to guarantee the required void space, and optimized the equipment's operational cycle. The blast crew carried out the activity without exposure to the risk of loading over void space. The wireless detonators also avoided after-blast activities, which were required to provide secure access to the blast crew, optimizing the operational cycle.

Jan 21, 2025

By Rodney C. Espley-Jones, John C. B Wilson

South Africa is well known for its shaft sinking exploits, and many of the world's biggest and deepest shafts are to be found there. Blasting practice differs in a number of respects from that followed elsewhere.

Jan 1, 1979

By Virgil J. Stachura, Larry R. Fletcher

The Bureau of Mines conducted a series of delayed blasting experiments at a West Virginia contour coal mine which resulted in smoother highwalls. The highwalls were smoother due to reduced overbreak and inherently safer due to reduced likelihood of rockfall. Reduced overbreak was accomplished by an increase in the highwall hole delay intervals which changed the effective delay pattern geometry and the direction of burden movement. Three combinations of blast delay intervals in the highwall holes were tested: 1) 50 ms longer than the nominal design, 2) 50- and 100-ms longer delays in the nearest two rows that form the highwall, and 3) 100 ms longer than the nominal design. The mine's nominal blast design was a flat vee formed by 17-ms surface delays between holes and 42-ms surface delays between rows, with 200-ms in-the-hole delays. All three test designs produced highwall improvements over the nominal design with only occasional exceptions because of geologic variations.

Jan 1, 1985

By U. Steiner

Electronic detonators have been in commercial use for a decade, with an excellent safety record. This paper lists known incidents involving electronic detonators. Typical standards required by regulatory bodies for static electricity and electromagnetic fields are reviewed. The performance of some detonators is compared to these standards; in general the minimum standards are easily exceeded. The general resistance of electronic detonators to extraneous electrical energy that can be derived from the body of test results is compared to danger levels for exposure of humans to these energies; it is shown that electronic detonators can safely tolerate higher electrical energies than people can. This comparison includes comparable data for electric detonators, which are shown to be more vulnerable to extraneous electrical energy than people are. Electronic detonators also bring significant safety benefits in blasting due to their testability, two-way communications, reliability, programmability and precision. The links between these attributes and enhanced safety are discussed with examples from actual blasting. Although electronic detonators are usually more vulnerable to extraneous electricity than non-electric initiation systems, the paper shows that the net safety benefit in handling and blasting is in favor of electronic detonators, which are the safest initiation system that has ever been offered to the mining industry.

Jan 1, 2010

By Roger Favreau, Patrice Favreau

Without blasting there can be no roads, no hospitals, no factories, not even foundations for homes. Yet in 1960 the only way to design a blast was by trial/error. By comparison, bridges were already designed by calculations before being actually built. This was possible because equations based on the fundamental principles of science existed with which all the stresses in the bridge could be calculated. In 1960 no equations based on the fundamental principles of science existed with which the mechanisms that take place inside the rock mass during a blast could be calculated. Since then the main author made it the objective of his research to seek such equations, and to validate that they gave accurate answers by means of experiments in the field, experiments made in co-operation with mines, quarries and the explosives industry; results have been reported in some 90 publications.These equations now deal with essentially all aspects of a bench blast: the intensity of the shock wave and the fragmentation size distribution throughout the rock mass; the movement of all the fragments into the muck pile; the fly rock and vibrations from the blast; etc.; are presented examples of such equations. They are now assembled into a computer simulator called Blaspa accessible on the Web, with which one can design a blast just as a bridge is designed. An example is presented. The reason to design a blast by simulations rather than solely by trial/error is that if it leads to damage, it is only after the actual blast that the blast design is realized to cause damage. If however the blast design had been simulated before the blast, then the risk of damage is identified before the blast and is prevented by redesigning the blast. Examples of such situations are presented. The need to a void damage is very necessary because the public is becoming opposed to blasting. When a blast does cause damage, and people learn that the blast was designed solely by trial/error even though simulation was available and would have prevented damage, they become even more strongly against blasting; they may succeed in getting a quarry closed. Their objections to unchecked blasting are not unreasonable, especially as simulating a blast with Blaspa on the Web is a very simple procedure.

Jan 1, 2013

By Ulrich Leiste, Andrew Wardlaw, William Fourney

This paper describes the loading on a plate suspended directly over an explosive charge submerged in water. This problem is of interest because it yields results similar to those obtained in the detonation of an explosive buried in saturated soil and thus it is associated with landmines. Recent experiments [1] indicate that plate loading from a submerged charge is similar to that for a buried one, with respect to impulse and pressure. Compared to the buried explosive problem, the submerged explosive case is attractive from a computational point of view; it replaces sand, which is diffi cult to simulate, with water, whose properties are well known. Studying this problem allows modeling uncertainties to be separated from sand simulation issues.

Jan 1, 2008

By Conny Postnpaok, Mark E. Hammele

"A major problem that has continued to plague the surface oil industry is blast induced damage to the coal seam. Atlas Powder Company has addressed this situation through several years of field research in full-scale production environments. Many operations across the United States havebeen evaluated ."

Jan 1, 1989

By Albert G. Funk, Gary M. Thornley

The available energy of aluminized ANFO and aluminized slurry blasting agents has been measured by seismic methods, calculated theoretically, and compared. With aluminized ANFO it is concluded that aluminum concentrations should be restricted to less than 10 percent because of diminished energy yields at high aluminum concentrations. However, with aluminized slurry it is concluded that efficient use of aluminum can be made at aluminum concert"rations up to 18 percent. It is further concluded that the difference in efficiency of use of aluminum by these two classes of blasting agents results from a higher contribution to useful work from the condensed detonation products of the relatively higher density aluminized slurry blasting agent.

Jan 1, 1981

By J. A. Rodgers, K. C. Whitaker

The time domain during which an explosive detonates and causes rock to fragment and displace is on the order of tens of milliseconds. Because of this, the dynamic processes that occur during this time frame often become a source of confusion when trying to analyze the performance of explosive products in decked blast designs. As an illustration, the authors have experimentally examined explosives malfunction in decked blasts through state-of-the-art measurement techniques. The interaction of explosive products and blast geometry was examined in detail using the analysis of a series of decked blastholes. Explosive and initiator malfunction in decked blasts is often considered to be entirely the result of insufficient inert decking material, however, it is shown that rock properties and dynamic burden conditions may have a significant impact on decking performance. The successful application of deck-blasting technique for control of ground vibration amplitude relies on an understanding of the true dynamic performance of the blasthole.

Jan 1, 2000

By Cory Loukides, Cathy Aimone-Martin

Blaster training manuals used by the Office of Surface Mining (OSM) and others are outdated and cumbersome. A new approach has been developed using Microsoft PowerPoint with a Visual Basic overlay to produce modules on CD’s that present state of the art blasting techniques. The education modules contain enhanced information on topics such as explosives and initiation products, blast design, drilling, and vibration control. The content is based on safe practices and illustrated with numerous photographs and movies. Review questions, complete with explanations for incomplete answers, enhance the learning process and keep the blaster involved. The benefits of using an electronic format include the ability to continually change and update the training modules as new products, technology and applications become available. In addition, the blaster can work at home in preparation for class work and may reduce the time away from the job. This poster session presentation will allow potential users to view and take part in the evaluation of these modules.

Jan 1, 2004