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By Kenneth K. Eltschlager, Richard R. Brochu

At the International Society of Explosives Engineers Annual Conference held in Nashville, Tennessee in February 1995, a Seismograph Standards Committee was established. The purpose of this committee was to develop objective performance specifications for vibration measurement instrumentation and field use practices. It was also understood that due to geology, temperature, and moisture in the soils, it is not possible to design and build an instrument to give results which are absolutely comparable for ground vibration. It was, however, considered essential to standardize instrumentation by which vibration can be measured under closely defined conditions so that results obtained by users of seismographs are always the same within stated tolerances.

Jan 1, 1999

By Charles B. Ingram, Neil E. Gehrig

The development of water gel explosive products has been the single most important development in explosive research and development since the invention of nitroglycerine and dyne-mite many years ago. m e Explosives Department of Gulf Oil Chemicals Company has been engaged in the research, development, manufacturing an marketing of slurry explosives and blasting materials for over twenty years. Explosive research and development is being carried out at the Jayhawk Technical Laboratory and the Underwater Testing Facility near Pittsburg, Kansas. There are fourteen manufacturing facilities geographically located around the country to serve the mining, quarrying, and construction industries with a complete line of explosives, blasting agents, and accessories. This paper discusses the Gulf slurry products, their properties, and uses.

Jan 1, 1977

By Dale L. Ramsey

Blasters in the field for years have been faced with the task of plotting blast locations for future reference and calculating scaled distances or seismograph placement from maps,aerial photo's etc.'With the constellation fully operational, GPS provides a satellite signal transmitted to a ground receiver which will display the desired coordinate positioning worldwide, 24 hours a day in any kind of weather conditions. There are a variety of GPS receivers available with varying levels of accuracy. The field trials of a handheld navigational quality instrument for plotting blast and seismograph locations along with other necessary industry related data is the basis of this paper.

Jan 1, 1994

By Erik Nygaard

Ammonium nitrate (AN) is the main ingredient in most industrial explosives, but it is estimated that as much as 80-90% of the global annual production is used as fertilizer [14, 25]. Over the last years AN has been involved in several accidents and used in criminal bomb making. Therefore authorities and legislators worldwide have given it special attention. This paper is divided into three parts: • The first part will focus on the accidents with AN that have occurred over the last years and possible scenarios based on official investigations. • The second part covers safety and security related issues. • The third part will summarize new legislation that is coming both within European Union (EU) and also on a global scale.

Jan 1, 2006

By S. Nakamura, H. Taniguchi, K. Noguchi, H. Sugihara, T. Matsuzawa

It has been reported that expanded poIystyrene and ANFO prills ‘were mixed on a blasting site for controlled blasting (ISANOL). Although there seems to be few possibility of their segregation because mixing on a blasting site is done, there is a great possibility of segregation in packing, transportation and loading of the product due to the different densities of the two ingredients in Japan where mixing on a blasting site still remains inoperative. The fiee-flowing property of ANFO prills was lost with the passage of time because the Abel oil infiltrated into the expanded polystyrene and that gave the product high viscosity.

Jan 1, 2001

By Jack Eloranta

This paper documents the relationship between material handling and processing costs compared to blasting cost. The old adage, "The cheapest crushing is done in the pit", appears accurate in this case study. Comparison of the accumulated cost of: powder, selected wear materials and electricity; indicate a strong, inverse correlation with powder factor (lbs powder/long ton of rock). In this case, the increased powder cost is more than offset by electrical savings alone.

Jan 1, 1995

By John A. Huber

At an underground limestone mine in the Central United States; there were plans for the installation of a limestone processing plant. The special design and layout of the plant called for the installation of a tunnel from the underground mine to the surface above. The dimensions of the tunnel would be 10 feet high, 20 feet wide, and would be 500 feet long on a 17 degree incline. The tunnel would be used for the transportation of raw stone to the surface by a conveyor. A second conveyor would transport processed limestone into the mine for storage, that would be loaded out for shipment later.

Jan 1, 1995

By Mark S. Stagg, Rolfe E. Otterness, Stephen Rholl

The Bureau of Mines is engaged in research to develop and test high explosive fracturing and rubblization techniques that will enhance ore body permeability and thus increase recovery during in situ mining. The natural permeability of many ore bodies is too low to allow successful in-place leaching. These deposits could be profitably mined if flow rates of leach solutions could be increased. Blasting represents a potentially low-cost and effective permeability enhancement technique.

Jan 1, 1991

By Sri R. B Singh

Based on CMRI investigations in nearly 50 mines, the authors have developed two empirical formulae for the effective determination of burden and spacing in any kind of rock deposit. Along with charge loading parameters, decoupling effect and bench height, the equations consider rock characterisation parameter by incorporating 'RQD' i.e Rock Quality Designation. The value of 'RQD' may be obtained either by core recovery using diamond drilling or theoretically from the characteristics of joints or bedding planes. The derived equations may be used in any rock mass under varying geologic and charge loading conditions. The Formulae suggested herein, are explicit, simple in form and easily applicable in field purposes. The values obtained from the present equations are verified against various field data generated by CMRI during the past several years.

Jan 1, 1998

By Yang Ruilin

Bulk gassing technology is a growing trend in the commercial explosive industry. The gassed bulk products produced differ from microballooned bulk products or cartridged products. It is easy to know the loaded or in-hole density for microballooned bulk products or cartridged products, whereas it is not as straight forward to know the m-hole density for gassed bulk emulsions. The loaded density is one of the key parameters affecting explosive performance and therefore it is important to have a field technique to monitor the in-hole properties of gassed bulk products in order to accurately predict the blast performance and to ensure efficient use of the products.

Jan 1, 1999

By J J. Mullay, G W. Anderson, C J. McFinley, J F. VanNorman, C J. Kefer

Previous work has shown that testing of precompression effects conducted on a small scale under simulated field conditions in actual rock provides a reasonable model for the evaluation of explosives and initiators under the adverse conditions encountered in production blasting. Using this methodology can result in greater understanding of the phenomena as well as the ability to predict performance. This effort has been extended to evaluate various parameters not previously studied in a controlled fashion. The present paper describes the use of this technique to study the effects of delay timing on precompression effects. Intervals from 25 to 150 milliseconds are included in the study. Both VOD measurements and damage estimates are utilized in the evaluation. The results demonstrate that timing delay between holes is quite important in determining the overall effectiveness of a blasting program.

Jan 1, 1994

By Bryan Papillon, Karl Christopherson

In order to improve vibrations from quarry blasting, a new technique and timing pattern was established and applied to the particular geology. By shooting a single representative borehole one full second ahead of the production blast, a signature waveform can be isolated and analyzed. Multiple productionsignature blasts were performed. Encroaching residences require quarries to adjust their blasting techniques to reduce vibrations and raise frequencies. A signature hole inherently poses problems to quarries. Blasting one single hole from a production bench poses safety issues to wall stability; vibration issues to close neighbors; and budget issues to the quarry operator. Results showed that the new timing pattern reduced vibrations through timing optimization without a loss in quarry production. Therefore, this technique of vibration analysis employing a production-signature hole is successful in creating a timing pattern that meets the quarry’s goals.

Jan 1, 2008

By Justus Deen, Paul Sterk

Overbreak into the wall rock of a development drift leads to the inevitable need to rehabilitate a drift. Moreover, overbreak in a production heading can lead to external dilution and lower ore grades. Both of these factors are critical to bottom line costs of underground operations today. The geology of the Homestake orebody makes this an even more complex problem. For over fifteen years the Homestake Mine has attempted to implement perimeter blasting techniques that are both safe and cost effective. Many practical perimeter methods and products have been tested including air decking; low density emulsions; various types of stick powder; various decoupling media including rope, low density ANFO, polystyrene ANFO, salt based ANFO, and various grain detonating cords up to 200 grain.

Jan 1, 1997

By John J. Ridgeway

Habits take us where we were yesterday and attitudes tend to keep us there. Until recently, little had been accomplished to improve conventional explosive energy for use offshore. But with the special requirements of the Offshore Oil Industry, and particularly in the North Sea, most equipment, products and services must be specialized as well. Previous attempts to excavate a trench for a sealine in surf areas had been impossible to accomplish. But with the application of safe, controlled explosive energy, an impossible task to accomplish yesterday has now become a reality. Explosive energy, often overlooked as a convenient and economical offshore tool, excavated a clean trench underwater for a 40" sealine at Djeno in the African Congo recently.

Jan 1, 1977

This case history refers to the detonation of the two largest chemical explosions on the Australian continent. An important element of feasibility studies and construction guidance included prediction of fragmentation results and ground vibration effects for the detonation of two very large "coyote" blasts, consisting of mined tunnels filled with explosives. The larger of the two blasts contained nearly 1 1/4 million pounds of explosives detonated instantaneously. The explosives were placed in specially designed tunnels under a quartzite mountain for the purpose of generating rock fill for the main dam on the project.

Jan 1, 1995

By Malcolm Scoble

The estimation of digging, ripping and blasting requirements in advance of mine production is a difficult task. The characteristics of the superficials and rock mass govern the type and intensity of ground preparation required as a prelude to loading. The incentives for optimum planning of preparation are primarily economic but also relate to mining method and equipment selection, productivity and environmental impact.

Jan 1, 1985

By Wendell W. Harris, Stanley J. Vitton

In the United States each year it has been estimated that expansive soils cause approximately $9.0 billion in damage to buildings, roads, airports, and other facilities. This figure alone exceeds the damage estimate for earthquakes, floods, tornadoes, and hurricanes combined. Unfortunately, some cases of expansive soil damage (swelling) are blamed on rock blasting operations if the blasting operations are located within the immediate area. While simple tests, such as the Atterberg limits test, can characterize a soil as expansive, it does not necessarily answer the question whether the foundation soils are causing distresses to a structure. In particular, it appears that once a soil has been labeled as nonexpansive it is no longer considered as a problem soil, in which case blast vibrations become the prime suspect.

Jan 1, 1996

By Koichi Kurokawa, Takeo Ueda, Masahi Nakano, Yoji Tasaki

A lightning strike generates several 10kA and several billion volts, and earth currents generated by lightning is dangerous to some underground and all surface blasting operations. In order to evaluate the safety against lightning in conventional electric firing method and electromagnetic induction blasting system, a test is conducted by connecting a wire with an impulse generator. Frequency of impulse current used in the test is 17kHz and the waveform is a vibration type and the duration time is 250 ~usec. The results of the test show that induced current increases with the increasing of impulse current. In the case of MBS connection, when maximum primary current is 1700A, Maximum secondary current is 11.8A and the electric detonator is fired at this condition.

Jan 1, 1988

By R Deshaise, B Mbhanty

The importance of controlling density of commercial explosives, and the various means to achieve it are described. m e field conditions responsible for density changes during blasting and their effect on blast results are examined. Understanding of the behaviour of density control ingredients such as gas bubbles, glass and plastic microballoons under pressure, is considered essential to predicting explosives performance. Both static and dynamic pressure effects have been studied for typical donor-receptor cartridge configurations. The amplitude and temporal characteristics of dynamic pressures inside receptor explosives have been studied by means of the underwater test, and guidelines developed to limit density changes due to external pressures.

Jan 1, 1989

By William McFerren, Pragasen Moodley

In contrast to global trends, African, especially South African, surface mining operations have shown a significant rate of adoption of Electronic Detonators (ED’s) over the last few years. Proven benefits of converting to ED’s from pyrotechnic initiation systems have aided this market conversion. These benefits are experienced throughout the mining operation. Benchmarking exercises, prior to the introduction of ED’s, form part of the conversion process and allow for quantifying improvements. Extensive work has been done on quantifying the benefits of converting to ED’s and have shown that results can be reproducible. Improvements have been experienced in many applications and include environmental impact control, improved mining efficiencies, increased cast benefit and improved size distribution. These step changes in blasting results, in conjunction with the adoption of ED technology have aided the rapid conversion of the African surface market.

Jan 1, 2004