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By Roger L. McCarthy, Ali Reza

The use of an ammonium nitrate-fuel oil (ANFO) explosive in the Oklahoma City Federal Building bombing has led to a renewed interest in using additives during the manufacturing process of ammonium nitrate to render it non-detonable. Suggested additives include calcium carbonate, which is already used in some European countries, and mono-ammonium phosphate (MAP) or di-ammonium phosphate (DAP), which are the primary desensitizing agents claimed in US patent 3,366,468, Method for desensitizing fertilizer grade ammonium nitrate and the product obtained, issued Jan. 30, 1968 (Porter, 1965).

Jan 1, 1999

By Gerald R. Coonan

Laboratory research is being conducted to substantiate suggested levels for voluntary standards on human response to transient vibration. The application of those findings to actual field conditions, however, will be limited because they will not include social and psychological factors existent in the real world. It is necessary, therefore, to examine available empirical information on complaints in an attempt to define the influence social and psychological factors might have on the laboratory results.

Jan 1, 1982

By P Cotton, N Cox

The Brisbane City Council has implemented a program of continual improvement at its Mount Coot-tha Quarry in the heart of Brisbane, Australia. The program has been underway for the past 6 years, and has resulted in very significant improvements in terms of both the cost effectiveness of its operation, and in terms of its environmental impact on nearby residents. The work has included a focus, amongst other things, on blasting efficiency, and has challenged conventional thinking in terms of the size of blasts fired, the frequency of firing, the diameter of blastholes, and the use of bulk emulsion or slurry explosives.

Jan 1, 1995

By Jeff Wachendorf

As the title implies, this paper details the start of a cast blasting and the design flexibility required to satisfy different parameters encountered on a large coal mine employing cast blasting as the program has grown and evolved around the town of Colstrip, Montana. As strip ratios have increased, the need to adapt and find solutions to provide coal at a reasonable cost to the mine mouth power plants has risen. Colstrip, Montana has a long history of coal mining which dates back to the early 1920s when Foley Brothers began supplying coal strictly for powering locomotive engines.

Jan 1, 2015

By Rodney C. Espley-Jones, John C. B Wilson

South Africa is well known for its shaft sinking exploits, and many of the world's biggest and deepest shafts are to be found there. Blasting practice differs in a number of respects from that followed elsewhere.

Jan 1, 1979

By Kenichiro Yamamoto, Masaharu Murakami, Toshio Matsuzawa, Yoshiyuki Ikeda

In a series of tests, we examined the dynamic shock resistance of Emulsion Explosive in water and compared it with that of Dynamite and Slurry Explosives. Both the distance between donor and acceptor charges and the delay initiation timing of the acceptor charges were varied. The resistance to dynamic shock varied with the properties of the explosive. In the case of emulsion explosives, there seems to be a certain proportional relationship between the critical detonation distance and the delay initiation timing. Some blasting results with emulsion explosives are described.

Jan 1, 1983

By J Foklesi, G Bohus, D Benedek

The breakage process in blasting takes place in space and in time and the latter will determine the degree of fragmentation, shape of the muckpile and the extent of displacement. The shock wave travels at the velocity of sound in the material and it can easily be measured. The cracks' velocity is only 0.38 % of the velocity of sound. The number of cracks at any distance from the explosion cavity, their length and the time of development can be calculated.

Jan 1, 1986

By Jack Eloranta

Transmission of sound through the atmosphere is affected by local conditions. Anecdotal accounts of the sound of cannon fire traveling great distances go back to the Civil War. The Royal Society published a paper near the turn of the century concerning the reports from the cannons fired in London at the funeral of Queen Victoria. Early computers were used by the U.S. Army at Aberdeen in Maryland in the 1950’s to model airblast problems during munitions demolition. Today’s blaster has to have access to weather information beyond a simple local forecast. Surface winds, winds aloft and temperature profiles have a dominant role in neighbors reaction to blasting. Many ground vibration complaints are really airblast complaints. Blasters who maintain ground velocities under . 1 inches/ second are often perplexed by complaints from distant neighbors, even when local monitoring shows airblast to be under 110 dB. This paper will help the blaster identify warning signs of high airblast conditions.

Jan 1, 2000

By Paul Worsey, Matthew K. Coy

New blasting mat designs are currently tested in the field on actual blasting jobs and only undergo qualitative rather than quantitative assessment. The majority of matted blasting occurs in trenching in which the blast designs and field conditions vary considerably. In order to assess a new blasting mat material and design, a new standard test was devised.

Jan 1, 2015

By Roger Lucas, Dale Nies

The McLaughlin Mine is an open-pit disseminated gold mining operation. Homestake Mining Company's approach to solving some of the blasting problems inherent to this type of deposit provide an interesting case history. Geology, although unique and site specific, is overall similar to other mines within the Western United States over-thrust belt and demonstrates an excellent example of the blasting conditions and requirements common to most of these operations.

Jan 1, 1990

By Young-Dong Cho, Han-uk Lim, Bok-Ki Park, Sang-Eun Lee

Many methods and techniques have been developed to reduce ground vibrations. Some of them are an adoption of electric millisecond detonators with a sequential blasting machine and an improvement of initiating system with an adequate number of delay intevals.

Jan 1, 1995

By Donald Jonson

The Arlanda Link project is for the time being the most interesting project in Sweden, concerning rock and blasting technology. The total amount of rock excavated beneath Arlanda airport comprises 800 000 m³ divided in four parallel tunnels measuring a total length of 8,5 km, with a rock covering of only 5-15 m between the tunnel roof and existing terminal buildings.

Jan 1, 1997

By E Castelli, M Fomaro, R Mancini, M Cardu

The economic return of rock blasting is not provided by brute volume of broken rock, rather by the amount of marketable product. That is the case of the porphyry quarries of Trento district, whose output is mainly absorbed by road paving and building facing elements production.

Jan 1, 1995

By Michael Swisdak, John Tatom, James Tancreto

In 2002, testing was proposed to generate needed data to assist in developing improved explosives safety standards within the US Department of Defense. This testing emphasizes two major areas: (1) full-scale donor/acceptor trials examining debris generation and acceptor response and (2) debris perforation testing of representative roof/wall materials. The full-scale donor/acceptor trials are referred to as the SciPan series. The first three tests in the SciPan series have been completed, as has the first phase of the SPIDER program. This paper describes the status and future of these testing programs, reasons for choosing specific tests, potential benefits, and planning for future phases.

Jan 1, 2006

By Thomas Palangio, Lyall Workman, Jack Eloranta, Tom C. Palangio

The fragmentation distribution of the blasted ore is an important descriptor of blasting results. Traditionally it has been hard to measure quantitatively. Developments in image analysis over several years makes it more feasible to measure fragmentation before crushing on a continuous basis. Post crushing, mill feed distributions can also be measured.

Jan 1, 2007

By Minoru Kawamora, Koichi Kurokawa, Kenji Hashimoto

We developed concentrated remote control blasting system to blasting simultaneously at a large number of sites in a mine of large scale. This system is consisted of three parts, the first part is a control station with high voltage power source units, the second part is a relay terminal with relaying and branching units, and the third part is a blasting machine with charging and discharging units. The control station is connected with the blasting machine by mean of control bus wire. The blasting machine adopts MBS(electromagnetic induction blasting system) for the reason of safety and good handling.

Jan 1, 1990

By Dwayne Tannant, Jeffrey Loeb

Blasting techniques and protective measures exist that can mitigate risks associated with flyrock and the nuisance of vibration, and overpressure. However, these are often misused or not used because there are no prescriptive regulatory requirements and typically urban blasting guidelines do not exist. The relationship between the increasingly negative publicity that the urban blasting industry receives and the existing state of regulatory control on blasting in urban environments is presented.

Jan 1, 2012

By Isaac E. "Chip" Harris

Any contractor who agrees to supply materials or to perform services for a sum, is well aware of the importance of proper pre-bid information. Being able to properly plan costs and methods results in profits that allow the contractor to prosper. The paper discusses procedures used in estimating pre-bid cost; in particular, drilling and blasting cost for highways, dams and general construction projects. It breaks cost down into five categories and relates them to a total estimate used in bidding and budgeting a construction project.

Jan 1, 1975

By Catherine T. Aimone

A series of experiments have been performed to characterize fragmentation and microcracking in quartz monzonite copper porphyry. The flyer plate impact method was used to generate plane shock waves in rock specimens for impact pressures between 1.6 and 7.3 GPa and impact pulse durations between 1.1 and 7.0 µs. The effects of pressures up to 4.8 GPa and pulse duration on fragment size distributions and microcrack densities were studied. The results show that pressures effect particle sizes to a greater extent at higher pulse durations. However, changes in pressure and pulse duration show little influence on the density of microcracks induced during explosive loading. These results indicate that the nucleation and growth of microcracks in rock subjected to shock waves occur uniformly throughout. A substantial decrease in particle sizes for high pulse durations is attributed to more time allowed for microcracks to grow and coalesce, forming individual particles.

Jan 1, 1985

By Jack Eloranta

Building on previous work, this paper expands the template for modeling the economic relationship between blasting and grinding. The actual efficacy of various blasting enhancements is not addressed, however, placing costs and potential benefits in proper context should aid in designing mine/mill optimization trials.

Jan 1, 2014