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By Lon D. Santis

The Code of Federal Regulations Title 30, Parts 56, 57, 75, and 77 require that detonators and explosives be separated by four inches of hardwood or equivalents when transported together in mines. This standard was developed to protect the explosives from initiation by the more sensitive detonators. The research reported here is an attempt to quantify the fire protection offered by four inches of red oak and other materials. Boxes with a volume of 6.75 cubic feet were made from four-inch thick rough green oak (RGO), two-inch thick RGO plied, two-inch thick #1 common (dried) red oak plied, and a metal/plywood composite. These and boxes meeting the Institute of Makers of Explosives' (IME) Safety Library Publication No. 22 were tested in bonfires. The boxes were instrumented with thermocouples, filled with detonators, and placed over a kerosene fire imparting about 16 kilowatts per square meter heat flux for up to 3 hours.

Jan 1, 1997

By Patricia Mendoza Watson, Lundquist Robert G

The velocity with which the burden moves after blasting is of concern for safety and economic reasons. Models developed for motion velocity by various researchers were reviewed and likely model parameters were used to develop statistically significant models. Regression analysis and residual analysis were used to determine the model coefficients and the accuracy of the models.

Jan 1, 1990

By Thomas J. Snyder

Modern quarry management should be alert to every opportunity to improve productivity and reduce operating costs. In this paper, the author outlines areas in which explosives suppliers should be encouraged to propose changes. He also supplies guidelines for evaluating these proposals, suggests yardsticks for measurement, and stresses the need to be open-minded when dealing with imaginative, innovative concepts.

Jan 1, 1988

By Don Rapp, Rufus Flinchum

Air blast and flyrock are two of the most critical concerns facing the blaster of today. This paper will provide the blaster with proven procedures for recognizing open face and bench surface problems, explain various surveying methods, and provide the mathematical formulas for calculating and designing proper hole placement and explosive load configuration. A concept called "Pattern Footage" is utilized in conjunction with a USBM study to develop blast designs aimed at minimizing air blast and flyrock. In addition to this main focus, this concept can be used in shot displacement and cast blasting design.

Jan 1, 1993

By J Lyall Workman, Peter N. Calder

The Manassas Quarry is a large industrial stone quarry in Northern Virginia owned and operated by Vulcan Materials Company. The quarry experienced instability in a portion of the north wall, which included toppling failure in a metasediment and movement on a major fault zone. It was necessary to take remedial measures to stabilize the wall and create good quality final pit walls.

Jan 1, 1992

A case history is presented where a variance was permitted by the court to change a 500 foot limit to 250 feet for blasting overburden at a surface coal mine in the proximity of a historic structure.

Jan 1, 1991

By Minoru Kawamura, Koichi Kurokawa, Yukio Kato, Kenji Hashimoto

It is well known that ground vibration by blasting is mainly related to a distance and charge weight. However, it is not known the correlation between ground vibration and performances of explosives; for example, shock wave energy, bubble energy, detonation velocity and ballistic mortar value etc..

Jan 1, 1991

By John Brennan

Necessity, they say, is the mother of invention. Certainly that sentiment held true during the early stages of explosive engineering. While seaside forts were concerned over static ignition of their black powder caches in the 14th century1, the mining industry in the 1800s were plagued by accidents surrounding the ignition methods for their black powder blasts.

Jan 1, 2011

The common approach of designing blasts on a trial and error basis is quickly coming to an end. When utilizing the full scale blast environment, trial and error can quickly become cost prohibitive and leaves much to be desired in terms of true blast diagnostics. In these situations testing is usually only continued until a perceived improvement is achieved and when the gross undesirables in blast results are removed. This does does not preclude, however, that further improvements of up to 100% or more can not be obtained.

Jan 1, 1991

By C. Pelley, S. Kelebek, G. Kunzel, P. Katsabanis

Small blocks of granodiorite have been subjected to blast loads from a single borehole and from a series of boreholes detonating at various timing intervals. The damage of the blocks was assessed through P-wave velocity monitoring, measuring the change of the point load strength index of the rock after dividing the large blocks into smaller ones and measuring the work index of the material at different distances away from the blasthole. Numerical modelling with the AutodynTM code enabled visualization of damage. It was shown that damage is optimum at a small delay time between successive holes while it drops rather drastically after this point.

Jan 1, 2003

By Jaime Huidobro, Mervin Austin

The effect on an explosive column of the sharp transient stress waves generated during the earlier detonation of adjacent blastholes is of paramount importance to explosives users. Some explosives will sympathetically detonate under these stresses. Others may suffer a transient desensitization, arising from a temporary increase in the density of an explosive beyond certain limits and persisting until the explosive mass relaxes back to the original density. Some explosives are so adversely affected by these stresses that the product suffers immediate and permanent loss of sensitivity. These effects can be clearly seen while blasting in tough conditions such as burn cuts or wedge cuts and in materials, such as coals, that propagate shock waves well.

Jan 1, 1992

By Claude Cunningham, Szendrei

The partitioning of blasting energy into “Shock” and “Heave” components is a popular concept for attempting to match explosives to particular ground conditions and blasting results. The issue is complex, as it affects both the detonation process and the immediate response of the rock skin. However, the fundamental process of energy transfer from the explosive to the rock through the blasthole wall is not well defined. Clues to the “Shock” phase of blasthole expansion are given by cratering behaviour of materials subject to high velocity penetrators. The final cavity volume defines both the energy used to achieve this and the resistance of the confining material. Attention is being given to the link between penetration of a solid target and expansion of a readymade hole, both producing the same outcome. The benefit of this work is that it leads to clearer understanding of how explosives will impact upon the blasting results and helps to explain the energy consumption in blasting.

Jan 1, 2004

By Michael Swisdak, John Tatom

In a quantitative risk assessment (QRA), the ability to accurately model real-world situations is obviously critical. In the end, the model must be able to represent the effects produced by the detonation of the donor and the consequences on the target. The science that goes into such a model must be carefully thought-out and based on as much data as possible.

Jan 1, 2007

By Virgil L. Lewis

On September 7, 1994, a Burlington Northern coal train crashed into a parked train in the downtown Gillette, Wyoming rail yard. I would like to address two issues in regards to this accident. One, a slide presentation of the damage created by the accident and the resulting required clean-up and two, a simulation of "what if" had there been an explosion during the course of the crash.

Jan 1, 1996

By Zoltan Susanszky

This paper discusses problems encountered when blasting under rivers for pipeline crossings. Many pipelines have recently been laid under the Danube River. Great care had to be taken to determine limits of detonation impulses from blasting operations in order that no damage would occur to structures at the water's edge, boats, and swimmers. Equations were derived from the results of this study which enable prediction of impulse levels.

Jan 1, 1977

By Frank Barker

Mining operations present a very different environment to the suppliers of explosives, initiating systems and services, both on surface and underground. Typical hazards include underground movement, air quality, ground stability, moving equipment, and the use of explosives. As contractors to the mining industry we do not have management control over the environment in which our people operate. The hazards and consequent level of risk that our people are exposed to in some mining operations are significantly higher by orders of magnitude than in a normal factory environment. Orica Explosives (and other Explosives suppliers) are continually and increasingly identifying opportunities to partner with customers by adding value through the provision of services leading to a reduction in total mining costs. These services include the provision of a bulk underground loading services, delivery of product into underground magazines, magazine management, value added blasting, conversions, rock-on-ground contracts, and blast management programs.

Jan 1, 2000

By Michael Beattie

A large open-cast limestone mine had its blasting operations severely restricted by the imposition of limiting PPV levels to protect a water pipe-line passing through the mine property. Attempts were made to measure the strains induced in the pipe by ground vibrations, so that a less restrictive blasting limitation could be established on a scientific basis.

Jan 1, 1992

By J R. "Dick" Daniel

In the fall of 1988, The Cannon mine decided to investigate a central blasting system based on conventional electric blasting detonators being used to initiate rounds primed with Nonel detonators. The advantages of this hybrid detonator system were viewed as being safety and cost effectiveness. A study was done reviewing the safety aspects of utilizing a permanent blasting line installed throughout the main haulage drifts to a central blasting station located at the mine portal. The study addressed the following potential safety hazards: radio frequency induced current, stray current from both electrical utilities and transmission lines, galvanic and electrostatic sources of extraneous current.

Jan 1, 1989

By D T. Froedge

To preface these remarks, it is not intended that this paper be a criticism of anyone or any organization involved in drafting the current regulations, for it appears that everyone involved in the process has made an extreme effort to be safe. We wish to show that in this case by making huge safety margins, we have created an unsafe condition in another area. That is by creating vast safety margins in the area of mobile transmitter intensity versus distance scales we have caused a severe handicap in the use of the mobile transmitter in securing blasting areas. The use of these mobile transmitters, which are absolutely essential in clearing areas where there are woods, mountains, or urban structures is virtually eliminated because of the safety factors prescribed in the regulations. We wish to show that these mobile transmitter safety factors are much too great, and can be traded off to increase the margin of safety in the ability to clear blasting areas.

Jan 1, 1975

By Sushil Bhandari

Presented here is the simplified process of fragmentation of homogeneous rocks by blasting based on experimental studies. Small scale single hole blasting experiments on jointed limestone are described. Results show that directions of joints overshadow the degree of fragmentation and also influence the remaining rock. The possible influence of joints on the process of fragmentation of non-homogeneous rock by blasting is also discussed.

Jan 1, 1983