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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 application 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.

Jan 1, 1996

By Greg J. Stach, Norman "Skip" Hale

The authors describe the development of an overburden blast casting program in the upper seam of coal at a 2-seam surface mining operation on property adjacent to an active operating underground coal mine. Control of vibration is essential.

Jan 1, 1984

By Roger N. Prescott

The Bureau of Alcohol, Tobacco and Firearms (BATF) is sponsoring legislation requiring the addition of identification taggants to commercial explosives. These are plastic particles with color coded layers that theoretically can be used to identify the explosive by date shift code.

Jan 1, 1980

By Stephen A. Rholl

Computer software has been developed which uses fast Fourier Transform (FFT) techniques to analyze the frequency spectrum associated with peaks in ground vibration time histories. The procedure consists of filtering the FFT of a time history into individual frequency components.

Jan 1, 1996

By T N. Hagan

Where explosion energy moves rock from the in-situ to its desired location without considerable assistance from digging and/or hauling equipment, good fragmentation is of minor importance. Maximum displacement must remain uppermost in the mind of the blast design engineer.

Jan 1, 1979

By A T. Spathis, J J. Felice, W Klass

Cast blasting has become one of the most efficient ways to move waste rock in open cut coal mining. It is used at Mount Thorley Mine in conjunction with a dragline to move some of the overburden onto the spoil dump.

Jan 1, 1992

By Robert C. Friend

On-the-job and "hands-on" training programs which attempt to train newcomers to blasting with instructors whose only qualification is their experience can easily miss the boat. Organized training programs which utilize competent instructors and a well developed format are necessary if we wish to provide a meaningful program of instruction, But, let's not go overboard and attempt to provide a level of training which goes far beyond the scope of the worker's duties and responsibilities, and "need to know",

Jan 1, 1980

By R E. Otterness, M S. Stagg

The U. S. Bureau of Mines conducted 22 full-scale blasts to determine the effects of delay and explosive type on fragmentation. The shots were conducted over a period of 7 years in three limestone quarries and one granite quarry. Hole diameters, bench heights, and number of holes varied from 6.4- to 14-cm, 6.7- to 14-m, and 4- to 24-holes, respectively. Explosive performance and actual firing times were measured and screening was used to assess the fragmentation.

Jan 1, 1995

By Steven V. Crum, David E. Siskind

In response to its own concerns and those of the public, industry and regulatory agencies, the Bureau of Mines is studying the impacts of low-frequency blast vibrations on structures. Previous research has identified potential problems associated with low-frequency ground vibrations and also found that their existence was not particularly rare, given large surface mine blasts and certain geologic conditions. Only a limited amount of data existed in the blast vibration literature on structure response to ground-vibration frequencies below 6 Hz.

Jan 1, 1993

By Leslie Taylor, W. Fourney, Uli Leiste

This paper presents the results from a series of tests conducted to investigate the total vertical impulse delivered to a target plate by a buried explosive charge. The tests were conducted at a very small scale but previous work has shown that small scale testing can predict impulse applied to plates in full scale. Non-deforming plates were used to determine the change in impulse delivered to targets as a result of changes in standoff distance and burial depth changes.

Jan 1, 2009

By J. Meissner

In this paper vibratory crack response is compared to that produced by volumetric changes in foundation soils induced by natural events. These natural phenomena include changes in the water table, changes in soil moisture, and formation of ice lenses to name a few. Previous papers have compared vibratory responses of cracks to atmospheric effects such as those produced by the passage of weather fronts and daily changes in temperature and humidity. Periodicity of these atmospheric effects is on the order of a day to half a dozen days. Thus it is possible to observe atmospheric effects with measurement over a period of weeks to several months. On the other hand, crack response produced by volumetric changes in foundation soils occurs over a period of many months and/or may be seasonal in nature if not longer in the case of drought. Thus its measurement requires long periods of observation (many months to significant fractions of a year) or observation during critical seasons. Since it occurs over long periods of time, its observation may be obscured by climatologically induced crack response. These soil volume changes are compared with climatic data to describe the correlative nature of crack response in time with the soil volume change phenomena and likely climatic causes.

Jan 1, 2009

By John Brown

Let’s talk about things that you, the driIl boss, the pit boss and the driller can do to eliminate the trend in drilling related accidents that have come to plague our industry in recent years. My paper will focus on reaI issues, problems and solutions that will affect our everyday outlook and attitudes about our jobs and lives. There are some real hard facts we must address if we are going to reverse this terrible killing trend.

Jan 1, 2000

By Brent Coleman, Wade Hutchison

The Montgomery Bell Academy project is a parking garage structure topped by a soccer field. This project included expanding parking and moving the present tennis courts. The project is located adjacent to an affluent historic neighborhood that posed some special public relations challenges.

Jan 1, 2012

By J R. "Dick" Daniel

One of the more common tasks in blast management is the adjustment of: shot geometry, explosive energy, and shot timing parameters to achieve changes in blast outcomes and costs. Many of these shot parameters, once a delayed blast is initiated, are modified by the development of new free faces which change the original or static input values to dynamic values. These newly generated dynamic values are easily calculated and find use in fine tuning shot adjustments and in rationalizing blast outcomes in a systematic manner.

Jan 1, 1996

By Paul V. Sterk, James Wieser

Mining in underground situations requires constant change due to changing ore bodies and economics. The Homestake Mine in its 122 years of existence has gone through numerous changes due to these factors. Recent sustained low prices in gold and ore bodies that are smaller or within mined out areas have forced the mine to reevaluate how these ore blocks will be mined. This paper will describe the design, drilling, and blasting of a complex ore block using the blind raise uphole bulk mining method.

Jan 1, 1999

By J R. "Dick" Daniel

One of the more common tasks in blast management is the adjustment of: shot geometry, explosive energy, and shot timing parameters to achieve changes in blast outcomes and costs. Many of these shot parameters, once a delayed blast is initiated, are modified by the development of new free faces which change the original or static input values to dynamic values. These newly generated dynamic values are easily calculated and find use in fine tuning shot adjustments and in rationalizing blast outcomes in a systematic manner.

Jan 1, 1996

By Ray Patterson

A planned modification to a cement kiln at the Holnam Portland Cement Plant near Florence, Colorado required the removal of a ring of cast-in-place (CIP) refractory lining. The CIP lining was approximately 14 inches wide, 12 inches thick and 38 feet in circumference.

Jan 1, 1999

By Petr Mostak, Miroslav Horacek, Miroslav Stancl

Detection of plastic explosives is an important task in the security measures against criminal misuses of this type of explosive. Particles and vapour detectors are basic instruments in this detection. Colour reactions and dogs are also used. Marking system in accordance with requirements of Montreal Convention was developed and applied in full scale production of plastic explosives including Semtex since 199 1. The influence of marking on technology, performance and other properties of plastic explosives is discussed. 2,3 dimethyl 2,3 dinitrobutan is the most popular marking agent which is broadly used. The detectability of this compound is not optimum by some detectors. The substantial effort has been given to development of plastic explosives with controlled shelflife. Some results of this work are presented. Technical and economic aspects of identification marking are discussed.

Jan 1, 2001

By Othmar Mueller

Building demolition techniques using blasting are different depending on the structure of the building, on surroundings, traffic, debris-transport systems, and re-usability of salvaged building materials, etc. This paper outlines some of the trends and problems in demolition blasting technique in Europe and especially in Hungary.

Jan 1, 1975

By A B. Jr Nunn, W C. Gould

Good community relations is a major concern at this central Virginia aggregate quarry. In this paper, the authors describe the use of a new electric millisecond delay initiation system that has reduced the average level of vibration by 27% since its use began in late 1984.

Jan 1, 1986