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By I. Petropouleas, J. Croll, R. Bassett

A programme of tests on controlled internal explosions to a class of circular reinforced concrete columns, has allowed the relationships between the blast energy and the extent of local damage to be understood. These tests have also demonstrated the important additional effects on the damage levels of preexisting axial loads.

Jan 1, 2006

By C H. Ryu

This paper presents a simplified two-dimensional numerical model of block fragmentation in a Jointed rock mass during the late or throw stage of a blast after wave effects have subsided. The model is based on the distinct element method. Examples illustrate the approach and allow for a comparison of effects of Joint patterns on fragmentation and resulting block motion.

Jan 1, 1986

By William Yutmeyer, Meredith Hardwick

Since 1996 there have been at least two teams formed within the U.S. Government to develop a consistent set of risk-based standards to be used to govern safety. The first of these was the Risk and Lethality Commonality Team which developed risk criteria associated with protecting personnel during launches at the national test ranges. The second team titled the Risk-Based Explosives Safety Criteria Team (RBESCT) is the subject of this paper.

Jan 1, 2007

By Shih Wen Wang, Ronald R. Rollins

A blast casting model is proposed to predict the burden velocity in bench blasting. This blast casting model is the first theoretical model that 1) explains the throwing procedures and mechanisms, 2) uses the explosion pressure as the primary source in throwing rock fragments, 3) applies them to field conditions successfully. Also the predicted burden velocities are based on the rock properties, the explosive properties, and the drilling and initiation patterns. This blast casting model is programmed into a computer software "ROCKFRAG". The comparisons between "ROCKFRAG" predicted values and two field test data are in good agreement.

Jan 1, 1992

By Huang Fenglei, Jin Qiankun

A new linear charge method has been applied in coyote blasting for highway excavation in which presplitting boreholes are set along the designed rock slope with some empty chambers at the end of linear charges whose axes are perpendicular to the axis of the highway. Three-dimensional nonlinear finite element analysis for this method has been conducted using LS-DYNA3D. The results indicate that the blasting damage to the rock slope is reduced greatly using the new linear charge method in coyote blasting.

Jan 1, 1998

By Mark S. Stagg, Rolfe E. Otterness, Stephen Rholl

The Bureau of Mines is engaged in research to develop and test high explosive fracturing and rubblization techniques that will enhance ore body permeability and thus increase recovery during in situ mining. The natural permeability of many ore bodies is too low to allow successful in-place leaching. These deposits could be profitably mined if flow rates of leach solutions could be increased. Blasting represents a potentially low-cost and effective permeability enhancement technique.

Jan 1, 1991

By Raymond V. Adolphson

The introduction of a new explosive component in 1955-56, called ANFO, featured much safer, effective blasting characteristics when compared to dynamite, accompanied by a notable reduction in cost. These savings mounted as borehole diameter or depth was increased with ANFO volume subsequently enlarged.

Jan 1, 1983

By Ivan Kovac, Pero Marjanovic, Branko Bozic

"The paper deals with results of geophysical survey of the rock masses, and the blasting parameterswhich have effect on the fragmentation in quarries . A relationship between the burden, which is the distance between the charged borehole and the free rock surface, and the velocity of longitudinal waves in the rock mass is established based on measured values for different quarries. It is shown that the drilling geometry can also be detemrined from this relationship."

Jan 1, 1999

By Rick W. Bellenie, Ronald L. Woolf

The Gregg River mine is located 40 kilometres (25 miles) south of Hinton, Alberta, approximately 330 kilometres (205 miles) west of Edmonton and lies against the Front Range of the Rocky Mountains.

Jan 1, 1994

By D Linn Coursen

Detonation propagates in the subject blasting agent at about 2.7 km/sec when it is heavily primed but explosion propagates in it at only about 0.43 km/sec when it is lightly primed. When propagating at 0.43 km/sec, it produces a borehole pressure that is slightly less than 1 kb, but no yellow fumes or other sign of incomplete reaction. It is a pumped AN/emulsion blend to which additional water is added by circumferential injection at the inlet of the hose through which it is pumped.

Jan 1, 1994

By P D. Kasbanis, Lyall Workman

The energy output of an explosive is typically calculated using an equation of state and computer applications. Results are reported as weight and bulk strength, either in absolute terms or relative to ANFO. The effect of the equation of state selected and the assumptions regarding the energy calculation are considered and interpreted for the purpose of blast design. It appears that variations in the heat of detonation which result from the selection of the equation of state and parameters associated with it are not sufficient to significantly affect blast patterns, explosive consumption and costs. However variations stemming from the use of "available energy" associated with a cut-off pressure are significant, suggesting in many cases large pattern expansions. The validity of the various approaches is discussed and blast design results based on the energy calculated by the different approaches are presented and evaluated.

Jan 1, 1996

By Jack Eloranta

This paper describes a method of evaluating shot performance through the use of available mine- data. The mine had already been monitoring the following parameters for other purposes: drill penetration rates, shovel loading rates, crusher throughput, crusher power and crusher hangups. By assigning pit coordinates to these factors, maps showing the location of difficult and favorable blasting are as are identified. Products and techniques are compared by the same method.

Jan 1, 1993

By Donald H. Matthews

The usual method of dismantling massive concrete formations with explosives, is to totally demolish the entire concrete structure. If any portion of a concrete structure is required to remain in its original form and retain its structural integrity, the use of explosives is usually forbidden and the portion to be dismantled is demolished by mechanical means, using various techniques and equipment that are tedious and expensive.

Jan 1, 1978

By Vilem Petr

Optimization blast design parameters for rounds used at surface mines, quarries or cast blast has taken on a new importance with the increased the cost of the explosives and electronic detonators. This paper addresses the fundamentals of blast design and optimization explosive energy utilized for fragmentation. This laboratory studies shows that one key variable-the strain energy set up in rock mass by blast vibration – can be used to predict the extent of damage done to the rock strata, the degree of fragmentation of the broken rock, and the velocity of the broken rock. It also shows how the dynamic strength of the rock strata is influence the fragmentation size distribution as well as the blastability.

Jan 1, 2008

By Jeffrey N. Deisher, H Y. Fang, Richard P. Scheller, Robert M. Koerner

The need to adequately quantify cracking in structures in the vicinity of blasting activity becomes more important each year. This urgency comes about through a growing number of complaints and lawsuits between the various parties involved, i.e., operator/owner, government, and complaintant. It is felt that existing rules and regulations (mainly based on peak particle velocity of the soil or rock adjacent to the structure in question) fall short of such quantification and lead to confusion in adequately assessing structural damage.

Jan 1, 1977

By Conny Sjoberg, Finn Ouchterlony, Bjorn Jonsson

This contribution reports an investigation of the blasting damage in the contour of an access ramp to a Swedish underground laboratory for nuclear waste related studies. Near zone vibration measurements were made for 7 rounds and the results converted to a site specific scaling law. A simple engineering correction for the influence of the charge length wee developed and the resulting equations used to predict the damage zone depths of three different drilling and charging patterns.

Jan 1, 1993

By Rodney C. Espley-Jones, John C. B Wilson

South Africa is well known for its shaft sinking exploits, and many of the world's biggest and deepest shafts are to be found there. Blasting practice differs in a number of respects from that followed elsewhere.

Jan 1, 1979

By Randall M. Wheeler

Many blasting companies are using simulated production ground vibration waveforms to aid them in the control of their vibration effects. The simulations are typically produced by using a seismograph to record a signature waveform from a single hole shot and subsequently applying the various delays to be used in a proposed production design. The ability of this simulation method to give good results usually depends on three primary factors. These are: 1) the homogeneity of the seismic travel path from hole to hole; 2) the consistency of the seismic energy release per unit of explosive from hole to hole; and 3) whether or not the delays fire as planned.

Jan 1, 1991

By N Vijay Mohan, K V. Balamukund, G Ananth Ramulu

Jointing of steel rods in reinforced concrete structures needs careful consideration as it renders the structure weak at the joint. The jointing is usually done at sections of structural members, where the bending moment and shear force are least. Jointing is done either by overlapping the rods or welding or by mechanical splicing. A novel method of jointing them is by inserting the two rods in a steel sleeve and cladding it on to the rods by subjecting the sleeve to explosive energy. A rod jointed in this fashion is tested for direct tension and bending when used in a reinforced concrete beam. The test results show that it is an effective method. The advantage is that a number of joints can be made in a single operation.

Jan 1, 1993

By J Foklesi, G Bohus, D Benedek

The breakage process in blasting takes place in space and in time and the latter will determine the degree of fragmentation, shape of the muckpile and the extent of displacement. The shock wave travels at the velocity of sound in the material and it can easily be measured. The cracks' velocity is only 0.38 % of the velocity of sound. The number of cracks at any distance from the explosion cavity, their length and the time of development can be calculated.

Jan 1, 1986