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By David A. Paul

Over the past several years a great deal of information on blasting vibrations and their effects on structures has been generated. Much of this knowledge has been gained through the use of ground vibration measuring equipment. While this type of information is valuable and gives us great insight into damage that can be incurred by structures from this source, very little, if any, information of this quality is available for the vast majority of cases in which an engineer is called upon to investigate alleged damage from ground vibrations. For the investigative engineer, then, the problem becomes one of accumulating whatever data is available and drawing a conclusion as to whether or not the subject structure was in fact damaged by the blasting vibrations. Such an analysis certainly requires a working knowledge of the literature on the subject and as much experience as he can bring to bear. Even thus armed, however, the data is often ambiguous, confusing, and/or contradictory. A practical approach is presented herein to aid the engineering investigator in arriving at the best possible conclusion available with the information at hand.

Jan 1, 1983

By Thomas Bakley, Rob Lee, Jay Rodgers

The present state of technology in Controlled Blasting uses standard explosives’ products to create a crack between holes along a desired line of break. The resulting pre-split, post-shear or cut line is often of variable quality with unwanted damage at right angles to the desired cut line. A new concept in Detonating Cord manufacturing has provided a radically different performing explosive. This new Cord has reduced the Velocity of Detonation by more than a third. It changes the Detonation Pressure proMe of Detonating Cord to a lower and longer sustained pressure pulse. In addition, it develops more gas than conventional cords. At the same time it maintains all of the handling and reliability advantages of conventional Detonating Cord.

Jan 1, 2001

By Francis O. Otuonye

An application of a time series and systems analysis modeling technique to blast vibration data is discussed. The vibration data was taken from a rock support structure and the surrounding rock mass at distances close (less than 15 feet) to a blast. The analysis technique provides quantitative information on the frequencies of ground motion as well as the frequencies and damping ratios of a near-field support structure.

Jan 1, 1994

By Norman S. Smith, Richard L. Ash

Many factors affect rock fragmentation from blasting. One variable seldom considered when designing blasts, however, is the borehole length. An example is described of how the length was adjusted to give better breakage when using 4-inch diameter blastholes at a quarry. To explain the basic principles involved test results from experiments conducted by the authors where borehole lengths were altered are presented and evaluated.

Jan 1, 1976

By D T. Froedge

Before this study was started, literature was searched and cases of alleged water well damage were investigated. Occurrence of ground water in Appalachia is primarily in low yield, fractured, water table aquifers. Four test sites were chosen based on geographic and geologic diversity. Test wells were drilled at each site and base line data on water quality, static water level, and drawdown characteristics were obtained before surface mining commenced. Blast-induced ground vibrations were measured at the surface by the wells at levels up to 5.44 inches per second maximum resultant particle velocity. Measurements made at the bottom of wells indicated that vibrations were considerably attenuated at depths of 140 to 160 feet.

Jan 1, 1983

By D K. Joyce, B Mohanty

"A variety of initiation modes are currently in use. This includes initiation by single ormultiple detonators and boosters, by detonating cords of varying strengths, and bycombinations of cords and boosters. A lack of clear understanding of the role of initiationon detonation characteristics often leads to under-utilization of the explosives system inblasting. This paper reviews the current practice of initiation in packaged and bulkexplosive products. It illustrates the effect of various types of initiation on energy releasecharacteristics in emulsion and ANFO, through calibrated underwater energy tests. Itcompares energy release under end-inidadon against side-inidadon condition for variousinitiator strengths. The effect of confinement on these characteristics has also beeninvestigated. It is shown that side-initiadon by detonating cord results, in most cases, insignificant degradation of detonation properties. This study also provides guidelines forselecting the optimum mode of initiation for various blasting situations."

Jan 1, 1993

Lightning Strikes on Vehicles Transporting Explosives The police in one of the countries in which we operate has asked about the consequences of a lightning strike on a vehicle (box van) carrying detonators and explosives. We have assured them that there is not a problem but they require proof of this.

Jan 1, 2011

By Corry Goumans

Photos 1 - 4 – Chris Elliott is a rock slope supervisor on a construction project east of Seattle, Washington. His job is to look after a “two man” scaling crew working on the rock bluffs some 300 feet in height along the I-90 interstate just east of the town Hyak. The Washington State Rock Engineers noticed a very large mass of unstable rock along the upper rock face and asked us to take it out. Chris is loading explosives in 1½" ” holes that are 8 to 10 feet deep by 40 feet long with 1¼” x 8” power primer on the unstable rock mass that is about 300 feet above the new road construction. I-90 runs east and west longside the new construction note the containment fence and the ship containers along the highway for protection and Lake Keechelus in the background.

Jan 1, 2014

By Peter G. Bellairs

The traditional concept of Optimum Drill and Blast is that it is achieved when ore is produced at the lowest unit cost and due to the complexities of most mining operations represents a band which extends either side of an overall cost minima. The above definition implies that Optimum Drill and Blast is static and once blasting is within the band around the cost minima then the process is optimised. However mining operations are not static with many events both long and short term impinging on the cost structure and productivity.

Jan 1, 1995

By Ronald R. Rollins

A continuous propagation velocity measurement probe has been utilized to determine velocities of slurry explosives, whole prills, crushed prills, aluminized crushed prills, in bulk and plastic screw tubes.

Jan 1, 1984

By Chantale Doucet, Mario Paventi, Malcolm Scoble, Yves Lizotte

Laboratory studies in homogeneous material indicate that the area of new surfaces created by blasting is proportional to the energy imparted to the material. Field studies, however, show that fragmentation is also related to the rockmass structure. This paper reviews ongoing compilation of a comprehensive and integrated blasting database which is based upon field monitoring and laboratory testing. A priority application of the database is to support attempts to more fully understand structural control over fragmentation. Database construction and the relative importance of rockmass physical and mechanical properties are considered in the paper. A methodology for data collection prior to, during and after blasting is reviewed. Data summaries from three case studies of blast performance in surface and underground mines are presented. These illustrate various aspects of the methodology, which included image analysis to quantify the fragment shape and remnant geology evident in the muckpile as part of the evaluation of structural control over fragmentation.

Jan 1, 1994

By Hubert den Dikken

ache, especially when it comes to forwarding of small quantities. Air transport is limited to 1.4 explosives on cargo aircraft and 1.4S classified explosives on passenger aircraft, so most samples cannot be transported by air. Ocean transport is a possibility, but due to stowage and segregation regulations of the IMDG code, a very expensive one. Road transport is often the only solution, but high explosives require special trucks with licensed drivers. The solution to these logistic problems is solved by creating a 1.4S (Class C) classification for all high explosives, when packed in special containment vessels.

Jan 1, 1995

By Wang Zhong Qian, Liu Hui

The paper proposed a fractal and damage model for rock-breaking by blasting, which assumed that the process of rock-breaking results from intrincent fractal development and the accumulation of damage. Remarkably, the process is of fracture character. Based on the model, a computer program is compiled to calculate the 3-dimension damage distribution in blasting crater. Trial results agree well with the predicted results, showing the model set up in the paper is sound.

Jan 1, 1997

By Surinder Singh, Vassilios Kazakidis, Damian Gregory

Safety, stability, and functionality of mine excavations depend on the structural integrity of the surrounding rock mass. Various explosives and perimeter control blasting techniques have been developed in order to minimize rock damage associated with the conventional drilling and blasting operations. The success of perimeter control blasting depends on many factors grouped in three categories: rock mass features, blast design and implementation, and explosive parameters.

Jan 1, 2008

By Peter Moser

The average annual consumption of raw minerals in Europe is 10 ton per person. About 50 % is produced by blasting. For a population of 450 million (including the population from the countries of the new member states) this makes 2.25 billion tons of blasted rock, 80 % being building industry aggregates and industrial minerals. In aggregate quarries 10-15 % of the rock blasted can’t be sold, as the material is too fine, i.e. smaller than 4 mm. This ‘fines problem’ is worse in the quarries of limestone and cement producers where up to 30 % of the material is useless. Thus about 450 million tons of useless rock fines are produced and put on waste dumps every year, i.e. 1 ton/person. This problem is addressed by the research project LESS FINES - “Less Fines production in aggregate and industrial minerals industry” which is funded by the European Union under the project contract G1RD-CT-2000-00438. The project consortium, formed of nine partners from 5 EU countries, works on the following two main research subjects: 1. The determination of the natural breakage behavior (NBC) of the rock mass, which is defined as the particle size distribution curve for a certain rock mass with the maximum uniformity and thus for a given maximum particle size that fragmentation curve which gives the minimum amount of unusable fine material. The comparison between the NBC and an actual blast fragmentation curve allows to quantify the fines reduction potential. 2. The adaptation of explosives properties, charging techniques and timing in order to produce only the minimum, inherently unavoidable percentage of fines. With about 15 full time working persons the project is estimated to be one of the largest blast related research activities in Europe at the time of the project period. The project is coordinated by the Department of Mining Engineering& Mineral Economics of the University of Leoben.

Jan 1, 2004

By Robert M. Carland, Horace Gene Biggs, David Holland

At a North Carolina feldspar surface mine, the orebody contains intrusions of waste material occurring at various angles from horizontal to dipping, and varying considerably in thickness. In order to obtain optimum feed for the mill, it is desirable to obtain maximum separation of ore from waste during blasting and digging.

Jan 1, 1990

By D G. Dressler, Paul Yeager

A previously little-known facet of seismic frequency spectrum analysis is gaining significance. The frequency spectrum of seismic waves promulgated from blasting is a significant factor in causing blasting complaints and threshold (architectural type) damages.

Jan 1, 1987

By Dale S. Preece, Lee M. Taylor

Computer simulation of the physics involved in conventional rock blasting can be split into two phases; transient stress wave propagation and rock motion. Because the two phases involve totally different mechanisms and time scales, they must be numerically modeled with two different computer programs. The first phase is usually modeled with a finite element or finite difference code which treats the rock ss a continuum and simulates the transient stress wave and subsequent fragmentation of the rock. The second phase is usually modeled with a distinct element technique where the rock mass after fragmentation is no longer treated as a continuum but as a finite number of distinct particles that interact with each other through collision mechanics.

Jan 1, 1989

By Dale S. Preece, Lee M. Taylor

Computer simulation of the physics involved in conventional rock blasting can be split into two phases; transient stress wave propagation and rock motion. Because the two phases involve totally different mechanisms and time scales, they must be numerically modeled with two different computer programs. The first phase is usually modeled with a finite element or finite difference code which treats the rock as a continuum and simulates the transient stress wave and subsequent fragmentation of the rock. The second phase is usually modeled with a distinct element technique where the rock mass after fragmentation is no longer treated as a continuum but as a finite number of distinct particles that interact with each other through collision mechanics.

Jan 1, 1989

By L M. Stodart

In the increasingly competitive environment of the 1990's, there is a need to provide the users of explosives with accurate and immediate information. Research has shown that information technology alone will not provide companies with a sustainable competitive advantage. However, where information technology is used to assist the development and enhance the performance, of the employee sustainable competitive advantage can occur. A Performance Support System is a tool that combines explosive's theory, government regulations, and site specific knowledge in an easily accessible computer program. In this paper five areas are addressed where a Performance Support System can assist the user: as a reference source, in an assistant or advisory role, as a instruction aid, in regulatory compliance, and as an operations monitor.

Jan 1, 1993