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By G Dean Barrett

Just one year ago at the 1986 Annual Meeting of the Society of Explosives Engineers, Dr. Calvin J. Konya presented a paper entitled "Presplitting Granite Using Pyrodex, A Propellant.'' Since that time more evidence has been developed to support the concept that "...gas energy can be the principal splitting force and that the stress wave or shock wave is not necessary to cause the presplitting action to occur." Work done in Vermont and Georgia is presented, and the ability to split granite without causing radial cracking of the bore holes is demonstrated.

Jan 1, 1987

By D Frantzos

Pressure time histories were recorded for low density ammonium nitrate/fuel oil, detonated in long heavy walled steel cannons of various bores. These were shell used in a finite element model of a horizontally layered limestone rock mass to predict the crack propagation limits in presplit blasting for a range of borehole diameters. Apart from showing very good agreement with field results, the model clearly demonstrated the strong dependence of the results on the pressure-time curve. The important elements were the peak pressure, the rise time to it and its duration. Control of these characteristics offers the possible future production of more ideally suited pressure-time profiles for the optimization of crack propagation distances and borehole spacings for various ground conditions. Also the results to date provide the basis for investigating the characteristics of the explosives presently used in presplit blasting, and finding ways to modify them with the purpose of optimizing the field results.

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 Bengt Ljung

Manual charging of long upward drilled holes in mines is a heavy and risky job today. Mechanization of this work has been requested for some time by miners, their supervisors, industrial safety organizations and the trade unions, all of whom are interested in improving the working environment. This paper presents newly-developed charging systems intended primarily for charging in connection with sublevel caving and sloping. These systems have been field-tested during 1977 in the LKAB mines in northern Sweden. The results of these field tests and the results of laboratory work conducted to help eliminate the risks involved in charging explosives are also discussed. The equipment being tested (see fig. 1 and 2) consists of a charging vehicle with articulated steering, the PT-60, which has been equipped with a hose feed system mounted on the hydraulic extension boom. From a sheltered position, the operator brings the detonator and primer to the hole opening, after which the hose is pushed in mechanically to the end of the hole. Measuring equipment indicates when and if the end of the blasthole is reached. The operator then withdraws the hose mechanically as charging takes place.

Jan 1, 1978

By E. A. McCullough, Jackson B. C., S. K. Metz

Public perception is a significant challenge facing the explosives industry. The public often perceives that its needs and interests are in direct competition with those of blasting companies’, leading to conflict between corporations and the community. This misunderstanding lends to unnecessary political and regulatory hardship, and ultimately, social discontent. Although individual corporations implement strategies to address conflict, many of these techniques are insufficient. Consequently, stakeholders resort to expensive litigation. If blasting companies could reduce or eliminate the volume of judicial disputes, valuable resources could be re-directed to more productive activities.

Jan 1, 2015

By Alan R. Cameron, Alastair C. Torrance

An explosives underwater test facility has been established and commissioned in the Hunter Valley, New South Wales, Australia which allows the measurement of the actual shock and gas energies of the explosive

Jan 1, 1990

By D K. Joyce

Large diameter boreholes have become increasingly popular in underground mining. Drilling equipment can drill full rings, including vertical upholes. Special techniques are required to load upholes of three inch to eight inch diameter. The current methods for loading AN/FO and bulk or packaged emulsions are described.

Jan 1, 1988

By Donald J. Westmaas, Fred C. Drury

The Great Lakes Region, in the states of Illinois, Indiana, Michigan and Ohio, uses approximately 14% of the explosives annually consumed in the United States. While materials being blasted differ widely over this geographical area, a basis of comparing practices is proposed and evaluated.

Jan 1, 1979

Blast performance is related to rock structure and strength, as well as to factors such as site geometry, drill patterns, explosives loading, firing sequences and delays.

Jan 1, 1986

By J Lyall Workman, Peter N. Calder

Flyrock can be a serious hazard associated with blasting. Many surface blasting accidents involving injury result from excessive flyrock beyond the protected blast zone. Numerous cases of equipment damage at the mine, quarry or construction site have resulted from flyrock. Fragments propelled beyond the property limits of the operation have also caused injury and damage.

Jan 1, 1994

By I E. "Chip" Harris, G Alan Foster

Whilst a great deal of published data exists as to safe ground vibration and air blast levels which result from blasting little documented research has been carried out to determine how and why human beings complain about blasting operations. This paper gives the authors thoughts and experiences of why complaints arise and practical steps to minimize such complaints.

Jan 1, 1977

By T. Bajpayee, G. Mowrey, D. Ingram, T. Rehak

Blasting operations are an essential element in the recovery of our Nation’s mineral resources. The mining industry uses billions of pounds of explosives annually. The majority of blasting occurs in surface mining .operations. Blasting results in the fragmentation and often the projection of rocks. Frequently, the rocks are thrown beyond the expected limits. Flyrock and failure to secure the blasting area dominate blasting-related accidents in mining, especially in surface mining.

Jan 1, 2001

By Unknown

Contact Local Law Enforcement Authorities. Contacting the local law enforcement authorities is essential to the quick recovery of explosives taken in a crime. Contact Local ATF Office. The local ATF office will work with the local law enforcement authorities investigating the theft. They can also assist in the preparation of the Theft/Loss Report for submission to the U.S. Bomb Data Center.

Jan 1, 2009

By Jim Breedlove, Stephen P. Case

When a major ground subsidence occurred in the AKZO Salt mine at Retsof New York, the company was forced to pick up their production from a lower mine level. Before full production on the lower level was possible, an escapeway and ventilation shaft would have to be constructed. Construction of a shaft under emergency conditions required some special techniques. Dynatec Mine Construction, Inc. of Lakewood Colorado was awarded a contract for the project.

Jan 1, 1995

By Peter F. Bayer, Fred C. Drury

This paper deals with explosives regulations in the State of Wisconsin. As has been typical elsewhere, there has been considerable pressure to add additional restrictions over blasting in Wisconsin. What we believe to be a novel approach to the problem has been developed and is being implemented. Members of this Society have been instrumental in this approach whereby the emphasis of the regulations is directed at permissible levels of blasting resultants rather than at specific methods of blasting. It is our intent that this paper serve as a guide to others who may become involved in similar regulatory review in other states.

Jan 1, 1984

By Alan R. Cameron, William W. Forsyth, Tom H. Kleine

In the production environment, the current limits of blasting are most often defined by the ability of the operator to drill blastholes from a planned collar location to the required toe location. Many problems which are initially described as deficiencies in blasting or support are directly related to drilling. The assessment of support performance and blasting efficiency must begin with a detailed examination of drilling practices.

Jan 1, 1995

By Sandra K. Penttinen

A difficult blasting project can go very smoothly when every precaution is taken prior to and during the blasting procedures. These precautions include conducting careful preblast condition surveys of nearby structures, initiating a good public relations program prior to the beginning of the blasting, and following a good safety program during the blasting procedure.

Jan 1, 1994

By P D. Katsabanis

Explosives malfunction due to shock waves is a serious concern for successful blasting results. Malfunction includes sympathetic detonation and desensitization of explosive charges as well as the modification of firing times of conventional pyrotechnic detonators.

Jan 1, 1995

By Eugene Baker

President George Bush signed the Safe Explosives Act (SEA), which amended the Organized Crime Control Act (OCCA) of 1970, into Law on November 24, 2002. As a result of this legislation, new restrictions on who could legally receive or possess explosives in the United States went into effect, resulting in a profound impact on the commercial explosives industry. The law went into effect in two key phases. The first phase, which went into effect on January 24, 2003, resulted in additions to the categories of persons who are prohibited from receiving or possessing explosive materials in the U.S.

Jan 1, 2004

By Yuji: Wada Ogata, Kunihisa Katsuyama

It is well known that a compressed stress wave reflects at the free face, it propagates to the backward as a tensile stress wave, and cracks grow when the tensile stress becomes the dynamic tensile strength. The behavior of these cracks has been discussed through the observation of the dynamic photoelastic high speed photography.

Jan 1, 1993