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By Richard Dooley

The purpose of this paper is to give a description of a controlled blasting program and why Georgia Power now has one; mainly because of the Spillway Project.

Jan 1, 1981

By C Deacon, M Jones, P Duniam

Electronic blast timing has been in use around the world since the mid-eighties, and, whilst it has yet to be used commercially by large operations on an ongoing basis, significant inroads have been made in niche areas where tighter control of blasting is required.

Jan 1, 1997

By Salah A. Taqieddin

In an open pit, or a quarry blasting operation, a muck pile of broken material of given size and quantities suitable to a load/hauling system is normally created at the foot of a bench. Fragmentation can be used to evaluate the efficiency of that blast configuration.

Jan 1, 1987

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

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 Paul Downing

Identity Theft Outline • What Are MY Chances??? • Types Of Thefts • Sources Of Theft Info • Stolen Identity vs. Background Checks • Information/Data Safeguards • Corporate Data Handling • Reclaiming Your Identity • Monitoring Your Identity

Jan 1, 2006

By Erkan Bayrak, Serkan Erkara, Ozkan Duzgun, Ekin Gungor

This paper presents part of the outcomes of the drill and blast optimization project carried out at Kisladag Gold Mine in Turkey. Kisladag Gold Mine is the largest gold mine in Turkey with a low-grade, bulk-tonnage, open pit operation that uses heap leaching for gold recovery. After blasting, the ore is fed to a three-stage crushing circuit which prepares crushed ore approximately -10 mm (0.39 in) for heap leaching. Crusher downtime analysis showed that blocky material and insufficient feed are causing significant downtimes with the primary crusher. This was supported by the fragmentation data collected to date. It was decided to initiate a fragmentation project to understand the variation in the run-of-mine (ROM) size with a view to provide a consistent feed to the crushing circuit. The study includes the analyses of the ore strength and structure, image analysis of the fragmentation pictures acquired from blasts, blast auditing and quality assurance and quality control (QA/QC) analyses. During this project, over 200 fragmentation pictures were acquired from 47 blasts to optimize ore and waste blasts. Ore strength varies between 30 and 120 MPa and rock quality designation (RQD) ranges between 30 and 100. A site-specific fragmentation model was used to calibrate the fragmentation for blast domains formed. In addition, alternative cases were simulated to achieve blasts designs with consistent ROM fragmentation size distribution. Alternative blast designs that include stemming length and powder factor changes were suggested. Long stemming length, drill cuttings use, free faced blasts, small shot sizes and poor stemming length control were some of the key issues causing coarse fragmentation.

Jan 1, 2015

By James W. Reil, Douglas A. Anderson

Blast vibration monitoring has generally been regarded as a necessary evil. New instrumentation and computer programs can change this. Rather than the usual trial and error methods to control vibration problems, an integrated, intelligent approach is possible. There is also the possibility of diagnosing problems with the blast vibrations.

Jan 1, 1989

By Robert B. Hopler

Hercules Incorporated has developed and introduced a totally new non-electric delay blasting cap system which utilizes a low energy gas detonation to activate the caps. Unlike any other initiation system, there is no hole-to-hole connection other than empty plastic tubing until the blast is to be set off. Only at that time, when all personnel and equipment are in the clear, is the special gas mixture introduced through the tubing. The actual time of firing is completely under the control of the operator, by pressing the fire button on the blasting machine.

Jan 1, 1977

"In order to increase control over blasting, it is important to identify the imperative mechanismsand to quantify their participation during the rock fracturing process. The useful energyreleased by the detonation of an explosive is split into shock and gas energies. The relativeimportance of these two energies in the rock fracturing process is still an area of active debate."

Jan 1, 1999

By Jesus A. Pascual de Blas

After 30 years of development and introduction, electronic initiation systems are now well established in blasting applications, both mining, quarrying and civil works. In terms of blast technology, it could be considered that timing is the new challenge: how to define the most appropriate sequence to improve fragmentation, reduce vibrations, avoid dilution, eliminate damage… Some classic tools have been updated and adapted to the new scenario, and are giving us good performance; on the other hand, others should be considered obsolete, given the accuracy of electronic initiation systems has exposed these tools to incoherent conclusions. Besides, other tools have appeared and are in use, providing new approaches to old issues. Additionally, not only the technical side has to be considered: safety, security, economics are well present in daily blasting activity and affect to the final decision: are electronic initiation systems the right answer to my blast?

Jan 1, 2019

By Alastair Torrance

The performance of commercial explosives is clearly influenced by the conditions under which they are used. Mining companies are supplied with Technical Data Sheets which provide details about explosive properties and its suitable application. These are generally produced using laboratory techniques which may not accurately reflect the quality and performance of the product in the field.

Jan 1, 2013

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

The Bureau of Mines fired seven test blasts in a 22-ft bench of limestone, screening the material to investigate the influence of explosive type and between row delays on fragmentation. Four 4-hole, single-row test shots were conducted evaluating dynamite, ANFO, emulsion, and a 60-40 emulsion-ANFO mix. Three 12-hole shots, with three rows of 4-holes, evaluated delays between rows of 24, 36, and 120 ms. Accurate in-hole electronic delays were used, firing within 1.5-ms of the nominal delay. All seven shots had a 6- to 7-ft burden, 10-ft spacing, with a hole diameter of 3-1/2 in fired on a 12-ms delay between holes in the row. The tests were instrumented with strain gauges grouted in the burden region examining stress wave and gas pressure effects. Fiber optic probes were used to confirm timing and to obtain detonation velocities.

Jan 1, 1989

By Donald J. Westmaas, Fred C. Drury

The Great Lakes Region, in the states of Illinois, Indiana, Michigan and Ohio, uses approximately 14% of the explosives annually consumed in the United States. While materials being blasted differ widely over this geographical area, a basis of comparing practices is proposed and evaluated.

Jan 1, 1979

By Gary Anderson, J. P. Remi Proulx

Rio Tinto’s Colowyo Coal Mine produces 2.1 million tons per year in northwest Colorado. Colowyo uses the terrace mining method to recover up to seven coal seams ranging in thickness from 5 to 20 feet. Coal recovery in the 6 foot thick high grade C-seam has recently been challenged due to large variations in the pitch and roll of the seam. As well, some coal damage was seen due to an increased thickness of the overburden consisting of a hard sandstone channel.

Jan 1, 2012

By Mark S. Stagg, Steven V. Crum

The Bureau of Mines is conducting research to develop methods to control fragmentation and improve productivity in surface mine blasting. As part of this research, PRONT02D, a two-dimensional finite element computer program developed at Sandia National Laboratories, was employed to model the fragmentation produced from RS-50, a single hole, reduced scale bench blast in a massive dolomite. The fragment size distribution obtained from the computer simulation was calculated using a submodel that utilizes the crack density and nominal flaw size values computed by PRONT02D.

Jan 1, 1989

By Alan Minchinton, Ian Kirby, Jim Chan

It has long been known that successful blasting in soft and hard rock can require the use of different explosives. While choosing an explosive of the right energy density is important, the dynamics associated with non-ideal detonation behaviour play an equally major role. Tuning the energy release rate of an explosive to optimise its blast efficiency can be likened to tuning an internal combustion engine to improve its performance.

Jan 1, 2014

By Thomas M. Keevin, Gregory L. Hempen, David J. Schaeffer, John M. Jr Pitlo

Repelling charges are small explosive charges detonated to frighten and drive fish away from a blasting zone just prior to detonation of a major explosive charge. Use of repelling charges has been recommended by natural resource agencies to mitigate the effects of submerged explosives. Blasting companies have used this technique in a "good faith effort" to reduce potential damages to aquatic resources. It has been assumed that noise or pressure generated by the small charge will drive fish from the immediate area, thereby reducing impacts from the much larger and potentially more-damaging blast.

Jan 1, 1997

By Mark William Withey

Blasting safety in surface mining is a necessary industrial goal. Proper techniques and disciplines exercised during the blasting process enhance the probability of achieving that goal.

Jan 1, 1995