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By Dale Preece, Stephen Chung

Mining and quarrying industries recognize blasting as the most effective method for breaking and removing large volumes of rock. However, the economics of blasting are often offset by the costly trial-and-error approach. Researchers in the field of blasting therefore design models to help eliminate the number of trials before finding the best feasible solution. Because of the complexity of blasting, a capable model would allow the designer to look at more than one variable at a time so that the most critical factor can be tackled.

Jan 1, 2002

By Anne Charline Sauvage

Blast designers and blasters need to know the rock mass influence on blast to increase explosive effi-ciency and to optimize costs, but also to succeed in limiting blast emissions (vibration, overpressure, flyrock) This paper presents an applied approach which makes it possible to structure the information con-cerning the rock mass and the blasting.

Jan 1, 2013

By Michail G. Egorov

As well as destruction and moving rock, the blast energy sets up a seismic wave in the ground and a shock wave in the air, which can present danger to buildings and disturbance to human occupants. This shock air wave potentially can cause to destruction of a window glass, the window and door frames and partitions of buildings. In modern buildings, distinguished with high flexibility, the shock air wave can cause to the intensive wall vibration, dangerous for these buildings.

Jan 1, 1996

By Robert L. Brooks

Blasting liability problems are frequently compounded by a company's inability to effectively communicate with concerned property owners and the lack of adequate complaint documentation. Often, by the time the insurance carrier becomes involved in a blasting claim, the situation has deteriorated to the point that a solution agreeable to both parties is virtually impossible to reach. The insurance carrier, wishing to minimize their lose potential may decide to pay on a somewhat questionable blasting claim rather than be drawn into lengthy civil proceedings that would ultimately end up in front of a jury with little chance for a successful outcome.

Jan 1, 1992

The reformulation of military explosives and solid propellants into commercial explosives offers a unique solution to the problem of disposing of high energy materials with essentially zero environmental impact at a low cost and with a salable product. Studies using the insensitive PBX PBXN-4 have been completed through the pilot plant stage and have been successfully tested as a mining explosive. A number of other military explosives have been examined and their VODs and heats of explosions determined and in some instances tested in 'field" operations.

Jan 1, 1995

By G Dean Barrett, Ed Jr Smith, Calvin J. Konya

The purpose of the project was two fold: 1. To determine whether Pyrodex, a propellant, manufactured by the Hodgdon Powder Company, could be used as a substitute for high explosives for presplitting in granite and other materials. 2. To determine if Pyrodex, a slow reacting propellant which produces no stress waves in rock because it reacts subsonically, could cause the rock to crack similar to the results achieved with high explosives.

Jan 1, 1986

By T Michael LeBlanc

Drill trajectory deviation is a recurring problem in vertical retreat stoping operations. As a result of this deviation, 60 kilogram (165 millimetre diameter) and 103 kilogram (302 millimetre diameter) explosive charges are routinely detonated beyond ore/waste contact zones. Consequently, there follows a reduction in finished stope wall stability and an increase in ore dilution.

Jan 1, 1996

By Curtis Garner

Griesemer Stone located in Springfield, Missouri has supplied aggregate in Southwest Missouri since 1946. In 1954 the decision was made to mine the formation and utilize the mined out area for warehouse space. As advancement proceeded, entrances and small diameter air shafts for ventilation were needed and had to be added. It was decided in 1989 to sink an 8' diameter air shaft designed to move 200,000 cubic feet of air per minute with the help of (4) four 50,000 CFM Loren Cook Fans.

Jan 1, 1991

By John R. Coulson

A survey of federal and state licensing requirements for blasters employed on the surface and underground was conducted for the Bureau of Mines. Subdivisions include surface and underground (large and small), metal, nonmetal and coal. The requirements for certification, class of license, available training, types of testing and enforcement practices are discussed. Included are recommendations of some of the industry trade organizations.

Jan 1, 1980

By H. Frank Murati, D. S. "Sax" Saxena

The presence of a mobile home park with drinking water wells created a unique geoenvironmental deterrent to the developer’s plans for effective rock blasting, excavation, and development of water management areas (lakes) in connection with the construction of Crown Colony Resort, a residential cum golf course community in southwest Fort Myers, Lee County, Florida, USA.

Jan 1, 2002

By Charles A. Kliche

The Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) established a national program for responding to releases of hazardous substances into the environment. The funding mechanism for this program is the Hazardous Substance Response Trust Fund (commonly referred to as Superfund), which provides funding for the implementation of removal and remedial response actions.

Jan 1, 1997

By Ed Jr Smith, Calvin J. Konya

The purpose of this paper is to describe the case history of a blasting project conducted jointly by Precision Blasting Services and Cherokee Explosives. It is the intent of the authors to show how blasting could be done in controlled fashion near very expensive computer controlled machinery. The job was done in minimal time with no complaints or allegations of damage in spite of the fact that blasting was conducted within five feet of the equipment and with the 32 acre plant fully operational, with machine operators working within 10 feet of the blasting site.

Jan 1, 1986

By J W. Edl, F C. Wu

In instrumented model rock blasting experiments in granite blocks, best fragmentation results were obtained when delays between holes were 1 to 2 milliseconds per ft. of burden and when a rectangular shothole pattern was used with spacings larger than the burden. Effective fragmentation in multiple hole blasts seemed to depend primarily on the full development of the crack network around each hole before the charge in the next hole was detonated. The test results showed that simultaneous or almost simultaneous initiation of shotholes in bench blasting resulted in poor fragmentation.

Jan 1, 1975

By Lee W. Saperstien

Section 709 of Public Law 95-87, "Surface Mining Control and Reclamation Act of 1977," requests the National Academy of Sciences to determine if the standards of the act are applicable to minerals other than coal. The Academy has established the Committee on Surface Mining and Reclamation to respond to this charge. The committee is, itself, organized to be responsive to the varieties of minerals, environments, mining systems, and locations that are representative of U.S. mining systems. It is not the charge of the committee to write trial legislation, but to indicate whether or not technology, extant or proposed, is available to meet the standards of the law, and at what cost. It is within this set of conditions that the committee will examine blasting.

Jan 1, 1979

By Norman S. Smith, Richard L. Ash

Relationships between the three design factors of borehole burden, spacing, and length that control rock breakage were examined by means of reduced-scale bench blasts in dolomite. A set of three indices were developed for analyzing the differences between fragment-sizing distributions obtained from various design combinations. It was found that the factors were interdependent and the indices were directly related to the common stiffness relationship for solid structures. The burden-spacing-length combinations that produced the best and poorest overall breakage, maximum and minimum overbreak, and least and most toe were determined.

Jan 1, 1977

By J S. Kuszmaul

The economic development of modified in situ oil shale retorting will benefit from the ability to design a blasting scheme that creates a rubble bed of uniform permeability. Preparing such a design depends upon successfully predicting how a given explosive will break rock. Numerical models are used to make predictions of the extent of damage caused by an explosion.

Jan 1, 1985

By Qingshou Chen, Paul N. Worsey

It has been recently argued that rock strength has little effect on the final results of pre-split blasting and is of only minor importance when blasting rock in general. However, it can be shown that the maximum borehole separation for optimal perimeter blasting results with constant borehole and loading configuration is strongly dependent on the tensile strength of the rock.

Jan 1, 1986

By Kaby K. Kabongo

The paper is drawn from a project intended to explore a technique of prediction, control and optimization of fracture in coal induced by blasting. It evaluates the fines generated in coal submitted to dynamic loading stresses in an impact stamp mortar. The aim is to analyze a complex phenomenon of coal response to blast-generated stresses from a series of discrete simulations of shock and gas actions in controllable processes.

Jan 1, 1995

By Kenneth Medearis

There is considerable evidence that more rational damage criteria need to be generated with regard to low-rise structures subjected to blasting vibrations. There is not sufficient basis for specifying a maximum ground particle velocity damage criterion such as 2 inches/second. A peak ground velocity guideline does not currently take into account a number of significant parameters, including the predominant frequencies of the ground motion excitation and the structure being excited. Although a number of states have adopted, or are adopting, maximum particle velocity criteria, such criteria have been ruled inadequate in certain legal decisions affecting blasting operations. The development of more rational damage criteria is thus of significant importance.

Jan 1, 1978

By Joseph A. Sohara, John J. Mullay, Curtis J. Keefer, Robert L. Schrepple

The desensitization of an explosive column by the action of a previous detonation (adjacent borehole, deck or detonating cord) is a vital concern to the explosives industry. Previous reports to this symposium and in other places have addressed this issue. However, this work has been mainly concerned with model or simulated conditions. No systematic study has appeared that utilizes an actual borehole environment. Thus the relation between this work and expected field performance is somewhat uncertain. The present paper attempts to partially resolve this difficulty.

Jan 1, 1990