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By Natalie Zeleznik, Brian Hawkins, David Bradley, Rachel Gooding, Patrick Wilson

"An Event Tree Analysis (ETA) is an established approach for logically deconstructing and assessing scenarios for probabilistic risk assessment. This deconstruction into a series of understandable eventsfacilitates probability estimation for explicitly defined explosive terrorism scenarios with consideration of modes of possible failure during execution (a scenario is defined through selection of a target, selection of an explosive material, and interdiction prior to arriving at general target location, etc.). Further, each event is decomposed into a range of possible outcomes. The physical action or reality ofthe outcome is statistically represented by “branches” of the event tree (e.g., the terrorist may choose totarget a stadium, hotel, or subway; terrorists may be successful or unsuccessful in acquiring the material)."

Jan 1, 2017

By D VanDoorselaere

"Image analysis techniques are widely used for blast fragmentation measurement, and various commercial packages are available for this purpose. These packages are very versatile and serve as a useful tool for optimization of blasting practice. But many times, the results provided by image analysis techniques do not match with sieved and predicted data. This leads to the suggestion that understanding the limitations of this technology is as important as understanding its usefulness and versatility.A study was conducted in two stages:(a) Comparison between the results of image analysis and screened data using laboratory scale muck piles.(b) Comparison between predicted (Kuz-Ram) and measured (Image analysis) blast fragmentation results for several bench blasts.During laboratory work, muck piles with known size distributions were analyzed with the help of image analysis technique. A disparity was observed between the sieved and measured results because the image analysis techniques cannot accurately determine the % of fi nes in the muck. During fi eld work about fourteen blasts were monitored. It was observed that predicted (Kuz-Ram) results rarely matched with measured (Image analysis) results. The Kuz-Ram curves were modifi ed by changing the rock factor so that the Kuz-Ram and Image analysis curves match in the vicinity of the 50% passing size. The pairs of curves (modifi ed Kuz-Ram and Image analysis) were divided into three categories depending upon their differences in the coarse and fi nes ranges. The blast design parameters affecting the difference between the pair of curves have been outlined. The suggestions have been made to better utilize the image analysis system."

Jan 1, 2007

By Dale Preece, Stephen Chung, D. Scott Scovira

The DMC_BLAST (Distinct Motion Code) has been developed to model rock motion and displacement during the gas expansion phase after the detonation of an explosive in a borehole. Recently, a designated delay firing order algorithm was written into the DMC_BLAST code. The model can now be used to analyze rock mass displacement for a V-cut, center opening, or sinking cut initiation sequences. This new feature allows the investigation of the effects of delay firing order on rock displacement when blasting complex inter-bedded and ore-waste structures. The model provides important ground movement and mixing indicators for dilution control in surface gold mining relative to the initiation sequences employed. Echelon blasts as compared to center opening type blasts show differences in their internal muckpile displacement. These displacement differences can be important to operations that mine narrow strike driven ore bodies. The model also has applications to through coal seam blasting and demonstrates that down-dip blasting is a better alternative than up-dip blasting. There is less disturbance to the dipping coal seam and less mixing of the rock and the coal.

Jan 1, 2000

By D. Goodings, W. L. Fourney, Bonenberger, R., Uli Leiste

The problem of the maximum depth at which a mine buried in the surf zone or beach zone is a threat to landing vehicles is being studied by Naval Surface Warfare Center (NSWC), Indian Head Division, Naval Research Laboratory (NRL), and The University of Maryland Dynamic Effects Laboratory. The problem was divided into two parts: The first part involves determining how deep a pressure plate mine can be and still detect a vehicle passing over it. This requires determining the distribution of stress within dry and saturated sand when a vehicle passes over a buried mine. The results obtained from that study are presented in a related paper (1). This paper will cover the second part, which entails determining the impulse delivered to the vehicle. This is equivalent to determining the impulse delivered to a plate suspended above the detonating explosive charge and includes an investigation of the distribution of the impulse over the plate. The purpose of the research is to develop a scaling law and/or computational capability which will permit predicting impulse to be expected in the field from tests conducted in the lab. The computational effort is aimed at the development of and confidence in computer codes that can be used to predict stresses and strains in plates due to the detonation of buried mines.

Jan 1, 2004

By Cristian Rodriquez, Fernando Fernandez, Rodrigo Fuentealba, Tom BoBo, Maria Rocha, John Kemeny

This paper describes a case study that was conducted at a new mine in South America. This mine has significant geologic variations that will result in different distributions of hard and soft ore being mined at different periods of time over the mine life. A study was conducted to determine the optimum blast design that will meet the mill throughput requirement of 95,000 tonnes (104,720 tons) per day for the first 10 years of the mine life. As part of this study, field rock mass characterization and laboratory tests were conducted. This includes standard rock mechanics tests as well as rock breakage tests used in mill simulations. The geology of the ore body was broken up into four Geologic Units, and statistical variations in the properties were determined for each unit. Using this data along with the data on the occurrence of the different geologic units over time, simulations were made of the run-of-mine (ROM) fragmentation due to different blast designs, and these results were used in simulating the resulting throughput after crushing and grinding. Four blast designs were considered with powder factors of 0.44, 0.54, 0.64 and 0.94 kg/t. The results of this study show that determining the proper blast design is important in ensuring that the mill throughput requirement will be met over the mine life.

Jan 1, 2015

By A. W. (Sandy) Neilson

Whether you are a general contractor who hires subcontractors to perform blasting work or you have your own blasting crew, it is extremely important to understand how Business Liability Insurance works, regardless of who is ultimately providing the coverage. If close attention is not paid to the limitations and preblast survey requirements under most policies that provide blasting coverage, you could find yourself facing an uninsured loss.

Jan 1, 2002

By Timothy D. Stark

Blasters are usually strictly liable for injury or damage caused by flyrock (trespassory invasion) and blast-induced vibrations (non-trespassory invasion). The application of strict liability to non-trespassory invasions has resulted in significant litigation that has hampered the use of blasting and the blasting industry. Stark (2002) proposes that blasters should not be held strictly liable for non-trespassory invasions but should be liable only if their conduct is proven to be negligent. This change in legal standard was proposed because improvements in blasting technology over the last thirty years allow blasting to be conducted without substantial risk of harm to property and thus the amount of harm imposed by a blast can be related to the level of care exercised by the blaster. It is anticipated that negligence standard will reduce the amount of litigation because a plaintiff will have a greater burden to overcome. To facilitate the acceptance of negligence standard by a court of law, this paper illustrates the application of the negligence and strict tort liability frameworks using actual cases in which a decision was rendered. It is evident from these cases that some of the successful claims under the strict liability framework would not have been successful, and probably not litigated, under a negligence framework, which could result in substantial cost savings to the blasting industry and consumers.

Jan 1, 2004

By Paul D. Dupree

This paper discusses the drilling and blasting techniques used in blast casting at a large western coal stripping operation.

Jan 1, 1986

By Mark Bauckman

Discussion Topics • Market Needs • Technology Developments & Best Practices • Industry & Government Developments • Future Possibilities & Your Role

Jan 1, 2006

By Edward J. Jr Walter

This paper discusses the use of slant hole drilling and water matting as an effective method of reducing costs in shaft sinking operations through a general review of cost priorities for the contractor.

Jan 1, 1976

"Blasting is an inherently destructive process and inflicts damage to the immediateperiphery of an excavation, which is later manifested as ground control and dilutionproblems. Different explosives release their energy and interact with the rock in differentways."

Jan 1, 1993

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 B. Hemphill

Each year the demand for precision blasting increases due to the reduction in the amount of prime land. More site preparation and hone building requires blasting than they did a decade ago, Because of this increased need for blasting in more populated areas, the need for blasters and engineers knowledgeable in work involving blasting nets has increased.

Jan 1, 1978

By Jaak J. K Daemen, Carol Geertson

A portion of a tailings impoundment may need to be removed with the expansion of an open-pit mine in northeastern Nevada. The tailings are saturated and consist of fine silty soil. During the removal of the tailings, they would have no support structure and vibrations induced by blasting in the pit could lead to slope failures.

Jan 1, 1998

By Jim Simpson, John Waller, Scott Stewart

The authors review the evolution of drilling and blasting procedures at this West Virginia surface coal mine where management seeks continually to improve and update the drilling and blasting programs. Today's operations require efficient programs which include quality control to maximize production and minimize the public's sensitivity to the blasting events.

Jan 1, 1992

By H J. MacDonald

An Exploding Bridgewire Detonator (EBW) is an explosive initiator which contains only secondary explosives such as PETN and RDX. It is safer than the normal blasting cap because it requires both high electrical energy and a very fast application of that energy to function

Jan 1, 1981

By S. P. Singh, Turgut Yalcin

The physical characteristics of blasted rock are fundamental variables affecting the economics of mining operations and are in fact the basis for evaluating the quality of a blast. A study was designed with the objective of quantifying the effect of muck size distribution on scooping operations in a mine.

Jan 1, 2002

By Sandra K. Penttinen

A difficult blasting project can go very smoothly when every precaution is taken prior to and during the blasting procedures. These precautions include conducting careful preblast condition surveys of nearby structures, initiating a good public relations program prior to the beginning of the blasting, and following a good safety program during the blasting procedure.

Jan 1, 1994

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 Thierry Bernard, Pierre M. Vuillaume, Michel Kiszlo

In the context of its studies for the french ministry of the environment and for the French national coal board, INERIS (the French institute for the industrial environment and hazards, formerly CERCHAR) has made a complete critical survey of the methods generally used to reduce the levels of blasting vibrations.

Jan 1, 1996