Search Documents

By Charles Pretorius, Henk Ludik

Navachab Mine experiences difficulties with pit wall stability in certain areas of the mine. The main reason for the instability is the fact that the geology comprises many joints and faults. Blasting, without impacting negatively on the stability of the pit walls, poses a major challenge.

Jan 1, 2006

By A R. Cameron

"The number of commercial explosive products available to the mining industry has been steadilyincreasing and associated with this there has been an increase in the range of characteristics or properties of them. This has lead to increased difficulties in selecting the most appropriate explosive for a particular blasting situation. Techniques are available that can be used to evaluate and compare the characteristics of explosives under a range of conditions. Also, the techniques are used to assess the variability in the characteristics between batches."

Jan 1, 1994

By Ethan Steward, Kyle Perry

Underground coal mines have several dangers, one the most hazardous of which is the possibility of an explosion caused by the ignition of methane gas. To reduce ventilation costs, coal mines have the option to close off abandoned areas that are no longer active with structural seals to keep an explosion from propagating into working areas of the mine. These seals must be designed to withstand different pressure levels based on the potential of the atmosphere behind the seal to become explosive, either 50 psi (345 kPa) for inert atmospheres, 120 psi (827 kPa) for non-inert, and over 120 psi (827 kPa) for special cases. Though seals have been designed to resist the overpressure, none have been evaluated for their resistance to the impact of heavy objects. Underground explosions produce high velocity gasses that, traveling through mine openings, may propel objects in the mine at a high velocity causing them to impact and damage the mine seals. Seals damaged in this manner may no longer hold the pressure they were originally rated for and may fail during subsequent explosions or leak explosive gasses into active workings. To test the effects of impact on mine seals, a projectile generator and two seals have been constructed. The projectile generator is a 12-inch (30.5 cm) inner diameter steel pipe with a 4-inch (10 cm) wall, is 8.5 feet (2.6 m) in length, and sealed on one end. Projectiles are propelled by a charge of black powder with a wooden wad and are held in place by foam sabots in the bore. This system, combined with the large bore, allows firing of many different potential projectiles that may be found in an underground mine at a high velocity into the seals. The velocity of each projectile is measured by an infrared chronometer which can later be used to determine its impact energy. Impact effects on the seals are measured using strain gauges, LIDAR scans before and after impact, high speed cameras, and visual inspection. The focus of this paper is on the projectile generator design and initial testing.

By Alastair Grogan

In October of 2002, the author was retained by Public Works and Government Services Canada, on behalf of the Department of National Defense, to design, construct and test the effectiveness of a bubble curtain system at an underwater demolition range, near Victoria, BC. The purpose of the bubble curtain was to reduce the potential for fish mortalities at the site. This paper presents some of the elements of the design, along with the results of overpressure monitoring during blasting and compares the results of fish mortality and animal behaviors with and without the bubble curtain in operation.

Jan 1, 2005

By Ken Cross

This paper aims to demonstrate that explosives organizations and workers have a legal, moral and financial duty to be able to demonstrate their competence when required, and how that may be achieved at any level from explosives storekeeper to senior explosives engineer on a major project. The concept of competence is outlined, as are the benefits to members of staff, management and the organization, particularly in a regulatory regime that includes competence management as a key performance indicator.

Jan 1, 2013

By Wilfrid Comeau

While researching for a theme lecture (Comeau, 1993l) on: 'The Mechanics and Physics Explosives', the author of Energy Transfer in Rock Fragmentaion by was confronted with many conflicting concepts regarding: the current explosive rock fragmentation theories, the physical principles governing energy transfers, the mechanical properties of rocks, and observations and data from full scale rock blasting.

Jan 1, 1995

By Ralph E. Burnham, Jeff Taylor, Jonson Montgomery, J. Kelly Ratliff, Rennie Montgomery, Martin Brashear

Top priorities for all blasting companies and individual blasters are risk management, safety of company personnel and the general public, regulatory compliance, and liability protection. On a daily basis, hundreds of shots are detonated by well-trained, skilled, and experienced blasters without incident. Unfortunately, accidents inevitably occur, which is why blasting is considered an “ultra hazardous” or “inherently dangerous” activity from a legal perspective. Despite countless regulations, recent advances in technology, improved training, ongoing research, and improved communication in the industry, mistakes and the resulting incidents continue to occur during blasting operations. These result in dangerous or deadly flyrock, site security lapses, increased complaints, blast damage claims, and lawsuits, which lead to increased insurance costs and other financial tolls for blasting companies. In life, lessons learned the hard way are rarely forgotten. The same is true in blasting operations. Blasting missteps and the resulting events are often the best catalysts for improving risk management and thereby reducing accidents, liability, and financial tolls. This paper provides a summary of two incidents, one safety and the other liability related, and the errors that resulted in a fatality in one case and a multi property lawsuit in the other. The two incidents provide examples that serve as a case study for lessons learned the hard way in blasting operations and offer guidance for the considerations that blasters and blasting companies should incorporate into daily operating procedures.

Jan 1, 2018

By Claude Cunningham

The primary reason for blasting is to fragment rock. In production blasting, the fragment sizes produced are known to exercise an overwhelming influence over working costs: handling costs and tonnage throughput are directly affected by secondary breaking, loading and crushing, all functions of fragmentation. In addition, particular size fractions are frequently of intense interest in terms of market or process requirements.

Jan 1, 1995

By Mark E. Hammele

A number of new thoughts have recently emerged concerning the role of air decks, stemming, gas confinement and gross motion in specific blasting environments and applications. Field research in full-scale production environments is based on the theoret ical work f i rst proposed at the Universi ty of Maryland’s Fracture Mechanics Laboratory.

Jan 1, 1989

By Douglas Bartley, Brian Wingfield, Robert McClure

Recent studies and limited tests indicate favorable results utilizing high accuracy electronic detonator technology over conventional non-electric pyrotechnic systems. This study discusses the application of this technology using the Daveytronic programmable system in an on-going production basis. The study quantifies the performance as it relates to fragmentation, excavation, vibration and productivity in an eastern U.S. aggregate mining operation.

Jan 1, 2001

By P D. "Takis" Katsabanis

The phenomenon of sympathetic detonations in blastholes is investigated by comparing experimental observations and numerical modelling results. Numerical modelling using the TDL computer code and Forest Fire decomposition rates for commercial explosives has shown the importance of blasthole diameter, impedance of the stemming and host rock. Comparison with experimental observations has also shown that sympathetic detonations cannot always be treated as shock to detonation transition. Examination of previous results which have been obtained from calibrated low amplitude shock experiments reveal that there is an ignition threshold prior to the detonation threshold. The difference between the two thresholds is more pronounced in the case of air bubble sensitized products. The ignition threshold can be very important under the confinement provided by the blasthole and the conditions of application. It also correlates well with the pressures expected at the gap distances of interest in the practical application. It is suggested that critical energies are used as the criterion for cross initiation in blastholes. Practical suggestions based on the numerical calculations and experiments based on these calculations are also given and discussed.

Jan 1, 1991

By L C. Taylor, H U. Lesiste

This paper describes a method for estimating the density distribution in the soil cap as a function of distance from its top at the time of impact with the target. It provides an estimate of the density distribution in the soil on the center line of the soil cap at the time of target impact for a single depth of burial of the charge and two heights of target and shows that, for the heights of target and the depth of burial considered, the thickness of the soil cap first increases from the in situ value and then decreases. The distribution of soil density along the centerline of the soil cap changes significantly with distance from its original position. These results can be used for validating hydro-code computations and the soil models used in the computations.

Jan 1, 2011

By Patrick D. McLaughlin

Crater blasting techniques have had relatively little application in the surface mining industry. This is not surprising, considering the geometry required to efficiently use cratering. The more widely known blasting operations that employ some form of cratering are listed below.

Jan 1, 1992

By John C. Brulia

The IME member companies, the ISEE along with its chapter organizations, the Federal, state and municipal regulatory agencies, and the industry consultants and suppliers have developed safety equipment, provided safety guidelines, promulgated safety-oriented regulations, and conducted safety training for blasting personnel in an effort to reduce explosives-related accidents.

Jan 1, 1994

By Laura Bustemante, Bruce Vandenberg, Fred Huettig

Recent advances in solid-state, field portable, fast framing video camera systems and PC based frame capture hardware now allow blast imaging up to 1000 frames per second. Up to 8 seconds of data can be stored directly into the unit, downloaded to a PC or archived to a standard VCR without data compression. Since no film processing is involved, motion analysis can be performed instantly and on-site within a few minutes. This paper will describe the design features and applications of the KineView 1256P system and compare these with the analogous aspects of fii based cameras.

Jan 1, 1998

By C B. McCampbell, R W. Jr Bickes

Sandia National Laboratories has developed a semiconductor bridge (SCB) igniter for the ignition of a variety of explosive materials. When subjected to a low-energy current pulse, the bridge bursts into a plasma causing rapid ignition of the explosive material pressed against the bridge. Despite the low energies required for ignition, SCB components have proven to be explosively safe, meeting both no-fire and electrostatic discharge (ESD) safety requirements.

Jan 1, 1991

By Rob Farnfield, Ben Williams, Ashley Haslett, Diane Cartledge

Major accidents that occur within our industry are often tragic and expensive, damaging reputation and threaten the livelihood of the business. There isn’t anything in them that can be seen as positive for those that experience them. They undertake what are usually very painful, detailed and time consuming investigations to discover how the incident occurred and what needs to be done in the future to prevent similar incidents occurring. Many admirably choose to share the lessons learnt through industry organizations such as SAFEX International so that we can all have the opportunity of preventing similar incidents from occurring within our own organizations.

Jan 1, 2016

There remains considerable controversy in the industry regarding precision type detonators and where the end user can benefit from their use. In spite of the fact that electronic detonators and other prototypes were tested over one decade ago, explosive suppliers have hedged on full scale production for many reasons. Although some of the reasons were based on solid economics, others were strongly influenced by shear internal resistance within the corporate objectives, ultimate fear of market rejection, indecision as to what degree of precision was required and limited data on defining the real benefits to the end user.

Jan 1, 1992

By Dimitri Frantzos, Stewart Thompson, Ed Skiba, Hans Tammemagi

On behalf of Acres International we would like to thank Frank Chiappetta of Blasting Analysis International for inviting our organization to participate in this state-of-the-art course on blasting analysis techniques.

Jan 1, 1989

By D. J. Goodings, R. J. Bonenberger, H. U. Leiste, W. L. Foumey

This paper describes a series of two-dimensional tests conducted and filmed with a high-speed (500 frames per second) video camera. The purpose of these tests was to provide a better understanding of the processes involved in creating craters and channels in water covered soils with explosives.

Jan 1, 2000