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By Thomas P. Dowling

Historically, laws controlling the manufacture, sale, transportation and storage of high explosives and regulations governing the use of explosives were formulated to prevent accidents or eliminate incidents that might jeopardize public safety. Many of the original laws and regulations regarding classification of explosives and blasting materials, tables of distances for separation and/or isolation of explosives, construction of storage magazines and methods of blasting were based upon empirical data, field experiments or scientific facts. During the past few years, however, it appears that some of the explosive laws and blasting regulations introduced and/or enacted by federal, state and local agencies seem to be based more on political expediency than on factual information or technical data.

Jan 1, 1976

By Fred C. Drury

The introduction and growth of modern chemical explosives based upon prilled ammonium nitrate has been the most significant development in the explosives industry during the 20th century. These modern chemical explosives have been of incalculable value to our society. Their use has permitted a reduction of blasting costs, improved safety, and the development of new resource sources which would not have been accessible without this new technology.

Jan 1, 1980

By Justus Deen, Paul Sterk

Overbreak into the wall rock of a development drift leads to the inevitable need to rehabilitate a drift. Moreover, overbreak in a production heading can lead to external dilution and lower ore grades. Both of these factors are critical to bottom line costs of underground operations today. The geology of the Homestake orebody makes this an even more complex problem. For over fifteen years the Homestake Mine has attempted to implement perimeter blasting techniques that are both safe and cost effective. Many practical perimeter methods and products have been tested including air decking; low density emulsions; various types of stick powder; various decoupling media including rope, low density ANFO, polystyrene ANFO, salt based ANFO, and various grain detonating cords up to 200 grain.

Jan 1, 1997

By Mark R. Fritzen, Ted A. Fritzen

Anytime that blasting operations will be conducted near existing inhabited structures, vibration damage claims are a major concern of the blasting contractor. It has been our experience that even when vibration and airblast levels generated from a blast are well below accepted damage thresholds, damage claims can still arise. The single greatest source of damage claims is the element of surprise associated with not knowing that blasting operations are being conducted nearby. The second greatest source of damage claims arise from the inability to produce accurate and detailed records of all blasting activity which provides evidence that vibration and air blast levels from each blast had been taken by seismic recording equipment.

Jan 1, 1994

By John Turner, James Lamb

The Minnesota Department of Transportation (MNDOT) has an extensive project to improve driving conditions and reduce hazards to motorists on US Highway 61 between Duluth, MN, and Canada along the north shore of Lake Superior. In 1991, the Lafayette Bluff Tunnel was completed just north of Two Harbors, MN, through a joint venture of Johnson Brothers Corporation of Litchfield, MN, and Obayashi Corporation of San Francisco, CA.

Jan 1, 1994

By Kamal Wadhwa

Ever since the introduction of Liquid oxygen explosives in India in 1927, these explosives are being extensively used in the various mining industries such as coal, ironore, limestone, bauxite, magnesite etc. The earlier LOX compositions were based on cellulosic material of Weberlox series of French origin. They contained the basic ingredients of saw dust with an admixture of cork dust, some hydrocarbons and some metallic powders. However, there were some inherent defects in the soaking characteristics of these compositions, in as much as, absorption and retention of liquid oxygen in the cartridges were not properly regulated in the fine pores and in the inter-granular spaces inside the ingredients in a uniform manner.

Jan 1, 1989

By Glenn Ludwig, Stephen H. Chung

Fragmentation has a direct impact on mine costs and productivity. Computer programs have been developed to calculate fragmentation using data on the properties of the explosive, the characteristics of the rock, the rock mass and the blast pattern. While computer models can yield good data, conclusions must be verified. Fragmentation assessment, muckpile surveys or high speed film analysis of rock mass movement are some of the techniques that have been used to confirm blast results. Digitizing photos of the muckpile is now the most common method to assess fragmentation. But it has some drawbacks. Although automatic electronic imaging equipment speeds up the process, the results depend on the photographs. Shadows will distort results. High resolution, black-and-white prints are essential.

Jan 1, 1992

By John Manka

Emulsion manufactures often spot buy the diesel fuel used in their fuel phases from various sources. Because their diesel source changes, there can be large fuel variation which may affect the quality of the resulting emulsions. This paper shows that the diesel fuel used in manufacturing emulsion explosives has a significant impact on emulsion stability and that the fuel additives dosed into the diesel fuel as it is made also have an impact on the emulsion characteristics and stability. We found that fuels with higher distillation ranges improve emulsion stability. We also found that while none of the diesel fuel additives affected the initial formation of the emulsion, some fuel additives did affect the characteristics and stability of the emulsions as measured by emulsion viscosity, droplet size, high and low shear testing, bin storage testing and freeze thaw cycling.

Jan 1, 2002

By Terry Matts, Henry Heidrich, Cluny Randell, Carl Kottmeier

Until 1990, all production of asbestos ore at Cassiar was by open-pit methods. With the impending exhaustion of open-pit reserves, a decision was made in February 1988 to continue mining underground, using the block-caving technique.

Jan 1, 1992

By Alday B. Andrews

A computer program called Seiswise that predicts the character and intensity of ground vibration generated by surface blasting operations was developed and field tested. The program uses the time histories of one or more pilot shots in combination with various initiation sequences to construct synthetic seismograms which are examined to select designs that will produce low levels of ground vibration.

Jan 1, 1990

By John C. Adams, Robin Irwin

In early 1993 a test program was designed to determine if mining costs could be reduced by using a high density ammonium nitrate mini-prill blasting agent. The goal was to reduce mining costs by expanding blast hole patterns while maintaining or improving dig-ability of the shot material. The program was conducted at Santa Fe Pacific Gold's Lone Tree gold mine near Valmy, Nevada.

Jan 1, 1994

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 Stephen A. Rholl

Computer software has been developed which uses fast Fourier Transform (FFT) techniques to analyze the frequency spectrum associated with peaks in ground vibration time histories. The procedure consists of filtering the FFT of a time history into individual frequency components.

Jan 1, 1996

By John F. Vynne

This paper will discuss the application of available monitoring technology on blasthole drills with the goal being to reduce costs and increase productivity. Case studies from the monitoring of blasthole drills in North American open pit mines will be used to illustrate the ability to meet these objectives.

Jan 1, 1997

By Josh Campbell

Modern blast engineering involves the use of modern technology to provide more efficient blasts. Through the use of improved measurement techniques more information can be obtained on many of the physical variables of a quarry rock face. By employing this information, a more efficient production shot can be designed and loaded. Along with improvements in production, greater safety and improved environmental impact can be achieved. This paper concerns the employment of modern blast engineering at a granite quarry in the Southeastern United States. The test period extended over a period of approximately six months, and this paper will show the results achieved in that time span.

Jan 1, 1998

By Philip Barnhard, Lyman G. Bahr

By recording the arrival time of a pipe wall at evenly spaced intervals in a plane perpendicular to the pipe axis, application of the equations of motion permits calculation of the pressure of the explosive acting to accelerate the pipe wall. Data observed from various non-ideal explosives are presented, together with values of pressure to be expected from thermodynamic calculations.

Jan 1, 1981

By Thomas L. Linton

The results of an extensive literature review and field experiments regarding the effects detonation of high energy explosive have upon various aquatic organisms are reported. These results were used to modify regulatory permitting criteria in Texas. Three separate field experiments were conducted. In the first study, surface placed charges were used in a marine habitat. In the other two, the charges were placed in drilled holes. In one, which was in a freshwater environment, the drilled holes were filled with drilling mud after placement of the charges. In the second, which was in an estuarine environment the holes were allowed to sit for thirty days prior to detonation to permit natural back-filling to occur by water transported sediments. A variety of aquatic organisms held in wire cages were exposed to detonations. Immediate and long-term effects of the exposure were determined based on external and internal visual observations. Damage to aquatic organisms was found to be reduced by placing the explosives in drilled holes and back-filling the holes prior to detonation of the explosives.

Jan 1, 1997

"Recently, an effort was made to calibrate the Riedel-Hiermaier-Thoma (RHT) material model to reproducethe behavior of granite under impact and explosive loading conditions. The study concluded that the materialmodel captured the phenomenon of compressional damage in granite due to such loading conditionsfairly well. The present work uses hydrodynamic modeling with the calibrated RHT model to estimate thefines generated around a blasthole. This can improve the calibration of different size-distribution empiricalmodels and enhance the prediction of fines."

Jan 1, 2012

By Carlos Agreda

The rock blasting environmental impacts such as: flyrock, groud vibrations,airblast,and/or noise, dust and fumes are identified and mentioned. Some comments on the correction factors that might be taken into consideration to calculate the initial velocity and the maximum projection of the rock fragments are mentioned as well.

Jan 1, 1995

By Frederick R. Cosgrave

Blasting near buried Natural Gas pipelines has always been an area of great concern. Given the many variables that the blaster must contend with in determining how to break the rock while trying to keep the vibration low and doing so while not compromising the pipeline.

Jan 1, 1995