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By Robert A. Farnfield

This paper outlines the theory behind transfer functions and illustrates their application in the prediction of structural response to blast induced ground vibration. The ability to predict the response of a structure to a recorded ground vibration is desirable for a number of reasons.

Jan 1, 1994

By Roger Holmberg, Dick Salomonsson

Nitro Nobel (the company was acquired by Dyno Nobel in 1986) originally developed non-electric initiation systems. These system were based on the 1967 invention of the shock tube fuse by Per-Anders Persson. Through licensees CIL and EB production and sales also started in Canada and the US. Early on, some accidental initiations of the tube occurred in production. It was found that static electricity was involved. After corrective action was taken - by changing the aluminium content in the tube core load - no further accidental initiations were reported until 1991.

Jan 1, 2002

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 Michael Weaver, Dale Ramsey

Description of Project: The National Gateway Clearance Initiative is an improvement program to achieve a minimum of 21 feet of vertical clearance along CSX Transportation Inc’s (CSX) rail corridor so that double-stacked intermodal railcars can be transported between mid-Atlantic states and their ports to midwest markets.

Jan 1, 2014

By R. K. Wharton, G. H. Pickering

The paper reviews the explosives products that have been certified by the different Explosives Notified Bodies for sale in European Union countries. The development of harmonised standards for explosives is also discussed as are recent developments relating to certification and a possible forthcoming Directive on pyrotechnic articles.Copyright

Jan 1, 2004

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 Thomas L. Barkley

This paper describes an unusual design for a 12 foot diameter, 30 foot deep circular shaft shot in a close in urban environment less than 100 feet from occupied structures. It uses diagrams, video footage, and vibration results to describe a 3 deck, 17 hole burn round used to pull 17 feet in one lift.

Jan 1, 1994

By Dale Nies

In the past, cap and fuse has been the only economical and efficient initiation system capable of providing sequential timing, ease of loading and hookup, and unlimited borehole number for backstope rounds. Unfortunately, in spite of these advantages, several negative factors inherent to the system have always been noted. Due to the long, narrow nature of backstope rounds at the Sunshine Mine, the cap and fuse system results in very long, inaccurate delay times. The system was also occasionally unreliable under all the conditions encountered, which in turn could cause potential safety hazards.

Jan 1, 1989

By David Lilly

The introduction of electronic caps with significantly more precise timing is forcing an examination into the practical effects of timing precision upon vibration, air blast, fragmentation and crusher productivity. These investigations have produced suggestions that techniques using multiple delays of the same period with conventional detonators might approximate electronic high precision.

Jan 1, 2006

By David F. Street

In order to achieve an efficient operation in an open pit mine it is very important to develop and maintain good coordination and communication between various departments within the operation. This paper will address this subject using methods and procedures developed at an open pit gold mine in northern Nevada.

Jan 1, 1994

By B Mohanty, R Deshaies

Initiation of small diameter explosives by sympathetic shock pressure in water has been investigated under controlled laboratory conditions. Changes either in the geometry of the donor explosive or its point of initiation can alter the essential characteristics (amplitude and duration) of the resulting shock pressure pulse. The pressure signatures from both spherical and cylindrical explosives donors have been studied, in water as well as in various explosive matrices. This paper summarizes the investigations carried out with both 'primed' and 'non-primed' slurry and emulsion explosive matrices with various types of voids. These measurements serve the basis for predicting distances in water for sympathetic initiation for both spherical and linear charges. It is shown that the explosive-detonator system in combination has a far greater probability of initiation due to sympathetic shock pressure than either the explosive or the detonator alone. Various explosive matrices with air bubbles and glass microballoons have been examined and the differing sensitivities to shock pressure explained on the basis of these measurements. It is also concluded that explosives containing air bubbles instead of microballoons would be significantly more prone to sympathetic initiation.

Jan 1, 1992

By Isaac E. "Chip" Harris

A general understanding is given to how and where blast hole drills are used and what recent developments have taken place with small and large diameter drill hole machines. Indications are that new developments with high penetration rates and large diameter holes are not necessarily the answer to increased production in the field.

Jan 1, 1979

By MSHA website

“Conditions at underground and surface coal mines can change dramatically during the winter months,” said Joseph A. Main, assistant secretary of labor for mine safety and health. “We must be ever mindful of the seasonal changes that can affect our work environments.”

Jan 1, 2011

By D Linn Coursen

In the proposed method, the charges are elongated and arranged in one or more arrays. The orientation of each charge in an array, its velocity of propagation of explosion, and the velocity of propagation of vibration in the formation are such that, at an outlying location where vibration is to be reduced, the onset of vibration from explosion of the first negligibly small increment of each charge arrives a finite time before that from explosion of the last negligibly small increment of that charge. The charges of each array are fired in accurately-timed sequence, with the times between initiations chosen so that, at the outlying location, the onset of vibration from explosion of the last small increment of each charge, except the last charge, arrives a negligibly small increment of time before the onset of vibration from explosion of the first negligibly small increment of the succeeding charge. With such timing, vibration may be reduced at the widest range of locations by tilting the boreholes so that the terminal end of each charge is directly above or below the terminal end of the succeeding charge.

Jan 1, 1995

By Paul Worsey, Randall Franklin

This paper is based on an undergraduate research project undertaken for the explosives emphasis in the UMR mining engineering degree program by the first author. The purpose of the selected research topic was to investigate the impact sensitivity of commercial detonators to determine their relative safety for handling and how much abuse they can take without accidentally firing. A modified BAM tester was used for the investigation. Both electric and non electric detonators were impacted at incremental positions along their length to determine the relative effect of their various components. Repeat impact tests were also conducted to see how a damaged cap would react to repeated abuse. The results indicate that it takes a significant amount of impact energy to initiate commercial detonators. They also indicate that repeated abuse can increase sensitivity. Modern commercial detonators appear to be relatively insensitive to impact (an order of magnitude above RDX in the standard BAM test) and this is mainly due to their construction. This explains why damaged caps with exposed powder are more sensitive. Their measured insensitivity correlates with rough handling not being a major cause of blasting accidents.

Jan 1, 2004

By Walter Voglauer, Elisabeth Zechmeister

Description of Project: The four photos show a chimney blasting operation in Vienna’s district of Floridsdorf on May 4 2011. The blasting was done with two types of charges. An internal charge provided a force of blast which resulted in 135 single electrical blasting caps initiated detonations on the basic ensured the straight collapse of the chimney. The preparation work was done by reserve force military engineers. The series of photos were shot by Elisabeth Zechmeister. She works in the Austrian DOD but not as a professional photographer; much more she did all activities in her spare time.

Jan 1, 2013

Tracer blasting is commonly used in Canadian underground mines for overbreak control. It involves tracing a column of ANFO with a low strength detonating cord. In order to investigate the effectiveness of tracer blasting in perimeter control and to understand its mechanism, a field experimentation was conducted which involved drifting, benching and pipe tests.

Jan 1, 1994

By C. B. Navalkar

The optimization of blast design under consideration is for the conventional driveways in under ground coal mines with respect to board & pillar workings in India. Basically The Blast Design includes following parameters: AA> Drilling Pattern. BB> Charging Pattern. CC> Material & Method Of Stemming. DD> Selection of type & quantity of explosives. EE> Initiation system & Blasting Sequence.

Jan 1, 2002

By V R. Sastry, D P. Singh, N R. Thote

Rock parameters which are uncontrollable impose restrictions on the procurement of desirable fragmentation. Blast design parameters which are controllable prove to be important tool in blasting operations. An attempt was made by the authors to investigate parameters which causes big oversize boulders in overburden blasting. A case study of coal mine is discussed in this paper.

Jan 1, 1995

Vibration resulting from blasting has been a source of concern from the inception of the use of explosives. As a result many investigations have been made concerning the seismic effects of blasting and at present there is available an adequate set of standards with which to judge seismically the damage capability of a blasting operation.

Jan 1, 1976