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By John Wright

During June and July 1999 a United States Antarctic Program (USAP) team of three commercial divers and one blaster successMy removed an underwater rock obstruction which interfered with safe docking practices of research vessels that call at Palmer Station - the USAP research facility located on Anvers Island, Palmer Peninsula Area, Antarctica. Ordinarily, such a project might be considered routine. However, certain aspects of the project, particularly those dealing with logistics in a remote corner of the earth, sat3eguards for marine biota, and working underwater in the dark of the austral winter, conspired to make this project interesting. Even more challenging was ensuring the protection of the existing pier - a deeply corroded sheet pile structure backfilled with loose gravel and rock - which lay less than 50 feet away from the target obstruction, not to mention uncertainties at the outset as to the nature of the rock mass forming that obstruction.

Jan 1, 2001

By FM Murray

SAFEX International is a global organisation with more than 85 members, all of whom are manufacturers of explosives. On joining each member signs a declaration saying that they are willing to exchange information with regard to any accidents or near misses they may have in order to prevent the recurrence of the incident. SAFEX International was formed 50 years ago in Europe and has now built up a database of more than 700 accidents in the explosives business. Once every three years, an International Congress is held in which members address specific safety themes associated with the explosives industry, and also give details of "what went wrong?", "why?", and lessons learned. The next Congress will be held in Amsterdam between the 29th May and the 1st June 2002. This paper describes the operation of SAFEX International, which is dedicated to the international exchange of experience on industry connected accidents of the explosives business.

Jan 1, 2002

By C M. Deosthale, V N. Pangal, M N. Rao

New Mangalore Port is the most important port in Karnataka State, on the west coast of India on Arabian Sea. It handles export of iron ore, granite, coffee, spices etc and imports of crude oil, fertilizers etc. Since 1991, after economic liberalisation by the Government of India, the exports and imports at this port got a boost. Hence the Port Trust felt the need to increase the draught by about 3 to 5 meters for access to bigger ships. In response to a global tender in 1995, the Dutch Dredging Company got the contract to remove 30,000 cu.m of hard granite bed rock, covering 28,000 sq.mtr. area for the Turning Circle and oil Jetty. The operations of drilling, blasting and dredging were to be carried out to deepen the area to about 15 m draught without affecting the normal trade at the Port. This was a time bound contract to avoid interruption by severe Monsoon rains.

Jan 1, 1999

By F O. Otuonye

Full-face blasts were fired in a 12 x 8 ft drift of an underground hardrock mine in a basalt formation with porphyry copper to study the effects of drill pattern and explosive type on the size distribution of the resulting muckpile. Each muckpile produced by five full-face blasts was sampled four times with a scooptram equipped with a 5-cu yd bucket and the size distribution of the broken rock in each bucket was determined by screen analysis. Results show a strong dependence of the fragment size distribution of muckpile on the blast pattern and explosive type for a given rock type. The mean fragment size of the broken rock was compared with the predictive equations of other investigators. Random sampling of the muckpile from full-scale blasts and screen analyses of the samples are recommended in assessing the size distribution of the broken rock because of scaling errors that are inherent in full-scale blasts when designed from results of small-scale tests.

Jan 1, 1985

By James T. Ludwiczak

The state of Kentucky uses more explosives than any other state in the country. The majority of these explosives are used in underground and strip mines in the well-known coal fields of eastern and western Kentucky.

Jan 1, 1978

By George P. Schivley

The careful positioning of the drill rigs that drill the holes into which explosives are then loaded is critical to the success of the subsequent blast. Today a system of satellites in space, each transmitting radio signals, is being used to provide the data to allow for tracking and positioning of various types of ground-based mobile equipment. The system is the Global Positioning System or GPS for short. This paper focuses on the application of GPS to surface mining and in particular the navigating of rotary drills from hole-to-hole and their final precise positioning to drill each blast hole.

Jan 1, 1996

By Karl E. Burgher

Accidental explosions occur throughout the world. They can happen at chemical plants, fireworks plants, grain depots, or as a result of collisions involving volatile or hazardous chemicals. It is interesting, as we know as blasters, that we can take two very harmless products and mix them under certain conditions and produce a violent explosion. It is often very difficult for the investigator to determine the magnitudes of blasts after the fact. However, an estimate must be made to settle vibration and airblast damage claims. The blasting consultant or technical representative is often called upon to act as an expert to mitigate these claims.

Jan 1, 1993

By Deane Tunaley, Paul Tidman, Qian Liu, John Mullay

Laboratory studies have indicated that the crystallization and desensitization of microballoon sensitized emulsion explosives start immediately after shocking or pre-compression. However, the question of whether or not the shocked emulsion could be worsened by the growth of crystallization or recovered by rebounding back to lower densities has been rarely examined under actual rock blasting conditions. This study was primarily intended to investigate the desensitization characteristics of two commonly used emulsion products in terms of blasthole spacing and delay duration. In the experiment, two parallel blastholes, 32 mm in diameter and 1.7 m deep, were drilled downwards in an underground drift.

Jan 1, 1995

By J R. "Dick" Daniel

In the fall of 1988, The Cannon mine decided to investigate a central blasting system based on conventional electric blasting detonators being used to initiate rounds primed with Nonel detonators. The advantages of this hybrid detonator system were viewed as being safety and cost effectiveness. A study was done reviewing the safety aspects of utilizing a permanent blasting line installed throughout the main haulage drifts to a central blasting station located at the mine portal. The study addressed the following potential safety hazards: radio frequency induced current, stray current from both electrical utilities and transmission lines, galvanic and electrostatic sources of extraneous current.

Jan 1, 1989

By Brian Wingfield, Rick Givens, Greg Williams

Many technological advancements have been made in explosive products and applications over the last 15 years resulting in productivity and cost gains. However, the applications of total energy (engine horsepower) in the majority of rotary drilling technology, has remained virtually unchanged over that period. While advancements have been made in components, efficiency, and types of hydraulic systems used on drills, the application of current hydraulic technology to improve drilling productivity has not been interactive with end users. This paper will investigate how traditional design assumptions, regarding typical application of horsepower in current rotary drill systems, can actually limit productivity.

Jan 1, 1996

By W Russell

This is an account of Cominco's explosives development work spanning 20 years from the introduction of ANFO into underground operations through to the present day where the use of blasting agents and sophisticated detonation systems create improved safety and blasting efficiency.

Jan 1, 1982

By James D. Cook, Dan McCutchen

Effective overburden casting requires the efficient use of todays explosives and initiations systems if a mine is to survive. This paper uses a major coal stripping operation as an example of the proper application of explosives and initiation system to their conditions.

Jan 1, 1994

By R R. Vendebeek

The continuing evolution of explosives has most recently introduced emulsion explosives and heavy ANFO's to the market place. An explosives engineer has a multiplicity of explosives to choose from: dynamites, slurries, water gels, emulsions, ANFO's, and mixtures of some of these products.

Jan 1, 1987

The most common method for identifying the potential for blast damage is the peak particle velocity. But this can depend on many factors such as the type of blast, explosive, confinement, timing and the rock mass. The value must then be used to estimate damage. But the amount of damage will depend on the rock mass quality and the excavation size and shape. The amount of damage that can be accepted will depend on the purpose of the excavation. This paper presents a logical, but very approximate, procedure that the mining engineer can follow in order to assess the potential for damage in the control of that blasting.

Jan 1, 1987

By Chantale Doucet, Yves Lizotte, Alan Cameron

A joint Federal Government-Industry research project on the effect of geology on the fragmentation of rock excavated by blasting in underground developments was conducted at the CANMET Experimental Mine, near Val d'Or, Québec. A total of thirteen (13) blasts were studied from November 1994 to February 1995. The analysis of each blast was divided into three stages: pre-blast characterization, including structural mapping, assessment of Rock Mass Ratings (RMR), Tunneling Quality Indices (Q), blast design documentation; blast characterization comprising blast vibration monitoring and analysis; and post-blast assessment comprising fragmentation assessment by digital photoanalysis, calculation of half cast factors and measurements of bootlegs.

Jan 1, 1996

By Herschel Sanson

Success of underground blasting operations depends upon a number of interrelated factors. These include conditions at the place, blasting methods, face preparation, type of cap, powder selection, transportation and storage. In addition, much of the work is closely regulated by state and federal regulations.

Jan 1, 1975

By Thomas L. Linton

The results of an extensive literature review and field experiments regarding the effects detonation of high energy explosive have upon various aquatic organisms are reported. These results were used to modify regulatory permitting criteria in Texas. Three separate field experiments were conducted. In the first study, surface placed charges were used in a marine habitat. In the other two, the charges were placed in drilled holes. In one, which was in a freshwater environment, the drilled holes were filled with drilling mud after placement of the charges. In the second, which was in an estuarine environment the holes were allowed to sit for thirty days prior to detonation to permit natural back-filling to occur by water transported sediments. A variety of aquatic organisms held in wire cages were exposed to detonations. Immediate and long-term effects of the exposure were determined based on external and internal visual observations. Damage to aquatic organisms was found to be reduced by placing the explosives in drilled holes and back-filling the holes prior to detonation of the explosives.

Jan 1, 1997

By Lon D. Santis

This paper reports on an evaluation of the safety characteristics of short lead, 5 centimeter (cm), Magnadet1 detonators. The Magnadet initiation system uses magnetic induction principles to transfer electric energy from the firing line to the detonator without a physical connection. This study was initiated because the Magnadet initiation system represents a new technology and the Bureau is interested in ensuring that no potential safety hazards are introduced into the nation's mining environment. The Magnadet system and its proper use are described along with a discussion of how it works. The potential hazards examined are: stray current from mine service power, lightning, DC current, static electricity, and radio frequency transmissions. Tip strength is also evaluated. Experiments were conducted to evaluate some hazards and theoretical methods were used to evaluate others. The results showed that the Magnadet short lead initiation system does not exhibit any unusual safety hazards. The new system is at least six times as resistant to common hazards as currently used electric initiation systems, so long as the insulation is intact.

Jan 1, 1992

By Charles H. Dowding

Public concern over blast-induced CRACKING has led to the search for a radically new approach to vibration control. The present system, while scientifically correct, is cumbersome to explain. Historically the potential for blast-induced cracking has come to be described through velocity time histories, which are correlated with observation of crack extension under controlled experimental conditions. Unfortunately time histories are simply too difficult for jurors and village or county regulatory boards to understand. Furthermore these arbiters must accept on faith that the observers were unbiased. Since these public bodies control the manner in which blasting activity is adjudicated and regulated, information must be presented in a form they can understand and that is not subject to second-guessing.

Jan 1, 1999

By Vaughn Bowns, Allen Stanley, Brian Redeker

"Running casing in drilling operations is often complicated by boulders or large cobbles.Past practices of dealing with these have included use of drop hammers, attempts to drillthrough or around the boulder, contact explosive charges and even pulling the casing andrepositioning the hole. All these methods are time consuming, expensive and offer noguarantee of success. In this paper a different method of dealing with these boulders ispresented that promises to be faster and less expensive with a much higher success rate.This involves using a light plastic conduit pipe to place a shaped explosive against theboulder. It requires no special tools or techniques not commonly in use in the drilling andblasting industry."

Jan 1, 1993