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By Harry L. Siebert

A major Arizona highway project is jeopardizing site safety and security because of the lane rental policy. One million cubic yards of rock must be fragmented to provide two additional lanes parallel to the existing roadway. Traffic is stopped during blasting operations.

Jan 1, 1997

By X Meng, W. A. Hustrulid, M. K. McCarter

Rock excavation in both surface and underground mining is largely accomplished using the drill and blast technique. At the perimeter of such excavations, cautious blasting procedures are often employed to minimize unwanted damage to the remaining rock. Of the several different techniques available, the use of explosive charges with a diameter smaller than the holes in which they are introduced (so-called decoupled charges) is the most common. In spite of the long and widespread use of the technique, a technically sound basis for relating the borehole wall pressure to the explosion pressure is still lacking. Such a relationship is required for optimal design

Jan 1, 2005

By Thomas Leonard, Philip R. Berger, Bryan E. Papillon

Bardon Trimount Inc., a large producer of aggregate, crushed stone, and concrete, was experiencing significant public opposition to its five quarries in the Boston area. It was believed by the authors that this opposition could be significantly lessened if the total number of blasts per week were reduced. Although the blasting company at these quarries, Austin Powder Company, contended that this could easily and safely be accomplished by increasing the size of the blasts, regulations precluded this alternative by limiting the total amount of explosives that could be used per blast.

Jan 1, 1996

By Ed Clah, Catherine Aimone-Martin

The vibration response of a 30 in. diameter high-pressure (845 psi) natural gas pipeline to 11 coal mine blasts was measured. The X-52 steel pipeline was buried 7 ft. below the ground surface. Ground and pipeline motions in terms of velocities were recorded on the pipeline, in the ground adjacent to the pipeline, and near the ground surface directly above the pipeline. These data were used to estimate the maximum stresses and strains in the pipeline occurring during the blasts. Pipeline standoff distances varied from 264 ft. to 3720 ft. Two blast hole layouts and timing schemes were used. One represented highly confined blasts to limit movement of the shot overburden that generated high ground motions at the pipeline. The second represented patterns that provided greater relief and lower the ground velocities at the pipeline.

Jan 1, 2003

By Fumihiko Sumiya, Shinya Tanaka, Yukio Kato, Kenji Tanaka, Tetsuya Sawada

When explosives are heated under an acidic environment due to metal sulfide and sulfuric acidity, their decomposition temperature falls remarkably and decomposition reaction occurs quickly, and then explosives have the risk of the deflagration to the detonation transition. Heat resistant commercial explosives which can be used under conditions of high temperature of 200ºC and an acidic environment were studied. We developed the explosive composition consisted of ammonium perchlorate (AP) as oxidizer, saturated hydrocarbon oil as fuel and binder, and calcium carbonate as decomposition inhibitor. The characteristics of this explosive composition show a heat resistance over 24 hours at 200ºC, and a detonation velocity over 2,500 m s-1. This explosive composition has a cap-sensitivity at temperature higher than 100ºC. Cost effective heat resistant commercial explosives were created by the optimization of the grain size of AP as a main component, the addition of saturated hydrocarbon oil and calcium carbonate, and the control of bulk density by the addition of micro-balloons.

Jan 1, 2003

By Wang Xuguang, Tian Ruigi, Xiong Shangbin, Xiong Daiyu

Combining action features of explosive shock with those of natural lignocellulosic biomass structure, we have successfully developed a new explosive shock dilatation and separation technique for pretreatment of natural lignocellulosic materials in the laboratory. Based on a brief introduction to the technical background and experimental procedure of this new method, some preliminary experimental results are given and discussed: the scanning electron microscope (SEM) qualitative observation results show that for treated natural lignocellulosic sample such as corn cob etc., their length of fibre bundle shortens, fibre bundle arrange disorders, biomass appearance and structure of samples largely change to be dilatation and loose state. The dilute acid hydrolysis quantitative measure results show that for treated samples, the overall yield of the reducing sugar largely increases, hydrolysis rate of corn cob sample is over 80%, rate and speed of hydrolysis are increased by times.

Jan 1, 1998

By Frank Chiappetta, Karl Zipf, Robert Hopler, Brian Stump, Francois Heuze, Bob Martin, Vindell Hsu, William Walter, Craig Pearson

The Comprehensive Test Ban Treaty (CTBT) was accepted for signature at the United ,Nations in September of 1996. It ‘now awaits ratification by its signatories, ~including the United States. After the Treaty is in force, the main concern of the international community twill be to verify that no nuclear test is performed.

Jan 1, 1998

By David G. Borg

Emulsions explosives, like slurries or water gels, are water based explosives. Emulsions were first introduced as a packaged blasting agent in the late sixties. Since then, many new variations have been developed, from small diameter detonator sensitive products to bulk loaded anfo/emulsion blends. Explosive detonation characteristics such as velocity of detonation, density/sensitivity relationship, strength, and water resistance along with how they relate to the type of rock and type of application will be presented. Various methods of sensitizing such as glass microspheres and chemical gassing along with product limitations and safety recommendations for bulk loading emulsions will also be presented.

Jan 1, 1994

By K B. Holm

This paper deals with the advances made at Syferfontein Colliery in the calculation and control of dragline methodology. The high capital outlay and operating cost of a dragline necessitates strict control of all aspects of the dragline operation. Before purchasing a dragline, a complete evaluation of all the parameters that can affect the viability, now and in the future, of the dragline operation needs to be completed. Such parameters as thickness of burden, material properties (swell), “castability”, pit width and pit length, etc. need to be considered.

Jan 1, 1994

By S A. Steyn, P Terrett

Air decking has become a widely practised method internationally for modifying fragmentation results and providing cost savings from reduced explosive consumption. Duvha has been applying air deck technology to overburden and midburden blasting for a few years. A thorough evaluation of air decking at Duvha has been made by instrumenting a number of blasts and analysing costs from direct savings in reduced explosives costs to savings in improved dragline productivity.

Jan 1, 1995

By Billy J. Thorne

The damage model in PRONTO simulates the dynamic fracture behavior of brittle rock. It is based on work started by Kipp and Grady, [lg] continued by Taylor, Chcn and Kuszmaul [I91 [20] and recently.modified by B. J. Thorne (first documented here). The essential feature of this model is the treatment of the dynamic fracture process in rock as a continuous accrual of damage in tension, where the damage mechanism is attributed to microcracking in the rock medium. The fundamental assumption of the damage model is that the material is permeated by an array of randomly distributed microcracks which grow and interact with one another under tensile loading.

Jan 1, 1989

By H. Rossmanith

This contribution introduces the fundamental concepts of wave propagation and fracture mechanics which form the basis of electronic blasting, i.e. precise initiation timing using electronic detonators. The concept of Lagrange diagrams will be frequently used for the calculation of the delay time between blast-holes in a row and rows of blast-holes. The effect of burden and structural geology will be briefly touched. It is found that the advanced blasting technology based on the use of electronic detonators introduces a change of paradigm. It will be shown that knowledge in wave propagation and fracture mechanics is essential for the successful application of the new blasting technique in industry. In particular, the delay time, the wave speeds in the rock mass, the shape of the wave pulse and the acoustic impedance mismatch have become decisive parameters in advanced blasting. Utilizing the wave speed and wave shapes of detonations, large scale tests Utilizing the wave speed and wave shapes of detonations, large scale tests in various countries (Australia, Chile, etc.) have shown that optimal delay timing requires shorter delay times in conjunction with allowing for a wider drilling pattern and the use of a reduced amount of explosives, i.e. a lower powder factor. This seemingly contradictory arrangement is fully justified by using scientific principles in blasting, and converting blasting from an art to a scientific discipline.

Jan 1, 2003

By B Mohanty, G Ludwig

A thorough assessment of development drilling and blasting practice was carried out at two underground mines at INCO operations in Thompson, Manitoba. The study showed that significant improvement in productivity can be achieved through careful selection of explosives and loading practice, and modifications of the standard blast lay-out. The analysis involved assessment of the effectiveness of various perimeter blasting methods, employing selected explosives and loading practice in both jumbo and jack-leg rounds. The blasting pattern as well as burden and spacing were varied to determine their effect on the blast results. The various types of explosives used were, pneumatically loaded ANFO, with and without detonating cord tracing, extra-strength detonating cord, and slurry and emulsion explosives with and without cord tracing. The study also dealt with various means to achieve increased rate of advance in both jumbo and jack-leg rounds. The diagnostic measurements consisted of VOD, 'burn' marks or half-barrels on perimeter wall, and blasting vibrations. The effects of geology, firing sequence, blast lay-out, and drill hole deviation on the final results were also examined. The results of the study have been shown to have very important bearing on the design of development round blasting.

Jan 1, 1998

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Umit Ozer, Ertugrul Kaya, Kagan Ozdemir

The results of bench blasting on quarries, have important influences on the performance of subsequent mining activities such as loading, hauling, crushing, grinding etc., and the total costs of that mine. Drilling and blasting is an important step in mine producing chain and its results such as fragmentation, muckpile shape and looseness, dilution, damage and rock softening effect the efficiency of downstream processes. Within the scope of this study, the three different hydraulic excavators’ working performances have been studied considering the particle size distribution after bench lasting at a quarry in Istanbul Turkey. Five shots have been realized on the quarry and average particle size of muckpile after each shot were assessed by digital image analysis method. Bucket loading times have been measured by stopwatch study after five shots. Excavator bucket loading times were also estimated by bucket loading time estimation formula which was published in ISEE 2007 Conference, Ozdemir et al. 2007. Estimated and measured times have been statistically analyzed and the accuracy rate of formula has been determined for five events.

Jan 1, 2008

By Jerry Wallace

A highway bridge demolition project to allow shipping access to a new container port in Puget Sound ran into trouble when contract-stipulated mechanical means of demolition failed. Blasting was then employed under less than ideal conditions and was successful.

Jan 1, 1999

By Marcello Crispi, Valdir Silva, Juarez Moraes

Companhia Vale do Rio Dote - CVRD is the largest mining company in Brazil and the largest iron ore producer in the world. Serra Geral Mine (SGM) is located at Iron Quadrangle of the State of Minas Gerais, approximately 80 kilometers from Belo Horizonte. Hematite and Itabirite are the two main minerals. A blasting with a spherical charge has been introduced at Serra Geral Mine, an iron ore producer in Brazil, belongs to the CVRD (51%) Kawasaki Steel Corporation (24.5%) others (24.5%), in order to improve fragmentation, as well, load, transportation and crushing productivity. This paper will present the results of a successful blast design with a spherical charge carried out by Serra Geral Mine, the Department of Mining Engineering at Escola de Minas - Federal University of Ouro Preto-UFOP associated to a Blasting Engineering Consultant. The results obtained in the field tests and how it was possible to increase the blast pattern in 53%, which allowed one reduction around 31% in the cost of blasting operation in the Serra Geral Mine, will be discussed in details.

Jan 1, 2002

By P Bellairs

The Hamersley Province is located 1000km to the North of Perth the Capital City of Western Australia and is of major economic significance due to the mining of extensive deposits of Haematitic Iron Ore for both domestic and export use. A small but significant proportion of the waste associated with these deposits presents problems due to its ability to spontaneously combust and react with explosives resulting in premature detonations.

Jan 1, 1996

By Richard Brummer, John Hadjigeorgiou, Patrick Andrieux

Some of the major challenges associated with underground mining at depth and/or under high extraction ratios are related to the resulting high stress levels, which can lead to the failure and collapse of the rock mass surrounding the excavations. Sudden and violent failures, which can have severe consequences, represent the highest degree of difficulty in terms of underground personnel exposure, erratic and unpredictable production, ground rehabilitation requirements, possible reserve losses and overall mining costs.

Jan 1, 2012

By Douglas A. Anderson

The simplest method used to predict ground vibration from blasting is scaled distance -the distance from a blast divided by the square root of the Pounds per delay. Pounds per delay is defined as the number of pounds of explosive detonated within an 8 millisecond (ms) interval. Based upon this definition, regression plots of peak particle velocity vs. scaled distance have been used to determine likely values of peak particle velocity.

Jan 1, 1989

By ATF Publications

The following is a summary of the changes that were incorporated into the new Federal Explosives Regulations, 27 CFR Part 55, dated 9/2000. However, in light of the recent events of September 2001, additional changes in the Federal Explosives Laws and Regulations may be forthcoming. The nature and extent of any such potential changes are impossible to gauge at this time. However, this synopsis of the changes contained in the September 2000 Orange Book, ATF P 5400.7 was current at the time of this writing. Any questions regarding this paper should be directed to the Public Safety Branch in ATF Headquarters in Washington, D.C.

Jan 1, 2002