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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 B de Raadt

After discussing mechanisms of collapse for the explosive demolition of towers in general and cooling towers in particular, author comments upon a blasting operation in which four cooling towers were involved. The intention of this paper is to present reliable parameters, generally valid for the explosive demolition of reinforced concrete cooling towers.

Jan 1, 1978

By Alejandro Ferrada Vergara, María Jesús Barros Godoy

Reducing costs while maintaining productivity and achieving good results is a constant challenge in mining operations, especially in the drilling and blasting stage, since a bad blast can affect production plans, increase costs, affect safety and jeopardizing the pit stability. Examples of undesirable blasting effects are: flyrocks, boulders, loading equipment damages, lower production rates, etc. In some of the biggest open pit mines using conventional blasting patterns visited by the authors, the pattern does not adjust properly to the rock mass, in most cases blasting polygons are large and the rock mass condition is variable within the designed blasting pattern. On the other hand, conventional blasting patterns with stemming columns use 40-50% of the blast hole with inert material (the stemming). Moreover, blasting engineers spend efforts to improve fragmentation results by increasing explosive charge in spite of having the negative effect of ground vibrations, with little or no success. The classic approach is "the more explosive in, the better the fragmentation is", furthermore it is assumed this relation is direct and infinite, but it is definitely wrong. This work challenges the notion of a limitless direct relationship between explosive charge and fragmentation, this means this is partially true but just up to a certain limit. In other words, there is still room to improve energy distribution among the classical blasting techniques without increasing the explosive energy by using air decks. In the work to be presented air decks are built using conical shaped stemming plugs called Paraplug®. The results obtained suggests a wedge effect acts in the bottom of the stemming column that cushions the shock wave and the air deck to reduce the detonation pressure (this is due to the decoupling factor resulted from the air deck). The demonstration shows improvements in fragmentation results, reduced vibration records accompanied with lower dust column and costs savings in explosive charge.

Jan 21, 2025

By M. K. Ameen, R. El-Hacha

This paper presents the analytical results obtained from numerical simulation of reinforced concrete slabs strengthened with various FRP systems and subjected to blast loading. A three-dimensional finite element model using AUTODYN software was used to predict the overall behavior of the slabs. The numerical results were validated by comparing with experimental results from a program carried out to investigate the efficiency of different strengthening systems on the blast resistance improvement of small-scale reinforced concrete (RC) slabs. The experimental program consisted of testing nine RC slabs strengthened with three different externally bonded (EB) FRP systems attached at the bottom side of the slabs and one RC slab tested without strengthening for comparison purposes. The EB FRP strengthening systems investigated included two layers of Carbon Fiber Reinforced Polymer (CFRP) sheets, two layers of Glass Fiber Reinforced Polymer (GFRP) sheets, and one layer of Glass-Fiber Resin Polymer (GRP) sheet. Different epoxy resin, patching mortars and impregnating epoxy adhesives were used for the slab surface preparation and FRP system application of the strengthening layers. The aim was to evaluate the residual strength of the test specimens after exposure to blast loads. The blast loading parameters were evaluated for each test using AUTODYN simulation and compared with the computer program CONWEP. All specimens were subjected to same spherical TNT charge weight and stand-off distance with the respect to the slab top surface. Extensive comparison is made between the experimental results and the AUTODYN simulations for the control unstrengthened slab and the strengthened slabs including time history records of the bottom steel strain and mid-span acceleration and the peak dynamic deflection of the slabs.

Jan 1, 2010

By Edward J. Walter

Vibration control is affected by many factors which are difficult to isolate and evaluate. Occasionally a circumstance occurs in which one factor appears to predominate and its effects can be evaluated. Changing rock characteristic or lithologic variation is one of these factors or parameters. In a recent seismic monitoring project, lithologic variation in the form of hard lenses occurring suddenly and randomly in the rock to be excavated caused sudden and large increases in vibration level. Data are presented to illustrate these effects, and procedures used to control these effects are described.

Jan 1, 1981

By Gungor Tuncer, Ali Kahriman

"In bench blast design, not only the technical and economical aspects, such as block size, uniformityand cost, but also the elimination of environmental problems resulting from ground vibration and airblast should be taken into consideration."

Jan 1, 1999

By Barbara A. Sciever, John H. Sr Schue

Riverboat gambling has caused quite a sensation among people since its talk of coming to Illinois. The year 1992 marked the start of an era for people that had a penchant for gambling, it was the year that riverboat gambling was legalized in the State of Illinois.

Jan 1, 1995

By Monica Stuckert

Field studies were made at an Appalachia coal stripping operation to evaluate the differences in cost and performance between blast casting with pre-split dewatering versus conventional coal overburden blasting.

Jan 1, 1985

By Qingshou Chen, Gongbo Li, Hengqian Ran

A method for safe fracture of rock, concrete and other brittle solid material using dynamic water pressure by explosion is provided. The propagation of the pressure is studied with Allievi water hammer theory. Wave equation and velocity formulas of the pressure propagation are shown. The dynamic water pressure is tested in the lab. The propagation of the pressure is simulated by MMIC-2D. The results of fracturing rock in the lab and on a quarry are presented.

Jan 1, 2000

By Vaughn Bowns, Allen Stanley, Brian Redeker

"Running casing in drilling operations is often complicated by boulders or large cobbles.Past practices of dealing with these have included use of drop hammers, attempts to drillthrough or around the boulder, contact explosive charges and even pulling the casing andrepositioning the hole. All these methods are time consuming, expensive and offer noguarantee of success. In this paper a different method of dealing with these boulders ispresented that promises to be faster and less expensive with a much higher success rate.This involves using a light plastic conduit pipe to place a shaped explosive against theboulder. It requires no special tools or techniques not commonly in use in the drilling andblasting industry."

Jan 1, 1993

By Dale Nies

In the past, cap and fuse has been the only economical and efficient initiation system capable of providing sequential timing, ease of loading and hookup, and unlimited borehole number for backstope rounds. Unfortunately, in spite of these advantages, several negative factors inherent to the system have always been noted. Due to the long, narrow nature of backstope rounds at the Sunshine Mine, the cap and fuse system results in very long, inaccurate delay times. The system was also occasionally unreliable under all the conditions encountered, which in turn could cause potential safety hazards.

Jan 1, 1989

By Thomas M. Keevin, Gregory L. Hempen

A user-friendly model for environmental effects from underwater explosions is presently available. The model by Munday et al. (1986) is effective for determining fish mortality radii from underwater shooting. The IBLAST program (Coastline Environmental Services 1986) from this model includes estimates for both borehole-loaded explosives for demolition or rock removal purposes and midwater shots. Midwater shots may be used for fish population assessments or some seismic surveys. The program produces approximate mortality distances for planning purposes. IBLAST does have serious shortcomings of which users should be aware.

Jan 1, 1995

By D K. Joyce, B Mohanty

"A variety of initiation modes are currently in use. This includes initiation by single ormultiple detonators and boosters, by detonating cords of varying strengths, and bycombinations of cords and boosters. A lack of clear understanding of the role of initiationon detonation characteristics often leads to under-utilization of the explosives system inblasting. This paper reviews the current practice of initiation in packaged and bulkexplosive products. It illustrates the effect of various types of initiation on energy releasecharacteristics in emulsion and ANFO, through calibrated underwater energy tests. Itcompares energy release under end-inidadon against side-inidadon condition for variousinitiator strengths. The effect of confinement on these characteristics has also beeninvestigated. It is shown that side-initiadon by detonating cord results, in most cases, insignificant degradation of detonation properties. This study also provides guidelines forselecting the optimum mode of initiation for various blasting situations."

Jan 1, 1993

By R. Ranjan

Stanstead granite has been investigated with respect to its dynamic compressive strength and its strain-rate dependency. A standard Split-Hopkinson Pressure Bar (SHPB) apparatus has been employed to generate strain rates of up to ~500/s through high-velocity impact. The diameters of the test samples were 19 mm, and tested under impact velocities up to ~20m/s. It is found that even within this limited range of strain rates, the dynamic compressive strength for the granite showed nearly a 100% increase in value compared to those obtained under static loading conditions (e.g. compressive strength of 394 MPa at a strain-rate of 600/s, compared to 215 MPa obtained under static loading). The details of the test are described in terms of incident, reflected and transmitted stress pulses, along with means to achieve stress equilibrium in the test samples under dynamic loading conditions. The advantage and drawback of the use of ‘pulse shaping’ techniques to achieve dynamic stress equilibrium are also detailed.

Jan 1, 2010

By Ronald Ticona

Generally, the drilling and blasting operation are managed independently to the processing plant outcomes. Therefore, the technical segmentation to determinate the ore drill and blast designs do not include processing plant rock properties such as Bond Work Index, Axb, Drop Weight Index or other. This work describes the case study of a copper mine in Peru, which, together with its strategic partner ORICA, have implemented projects focused on optimizing mine fragmentation. The year 2021, mine operation according to its mine plan would have a significantly increased SAG mill hardness, which would impact directly on copper concentrated production. An integrated strategy from mine to plant has become necessary to maintain the production levels.

Feb 6, 2023

By K. Hausmann, W. Whelchel

The properties of ethylene Ionomer resins for the inner layer of non-electric shock tubes will be discussed in detail, and opportunities for property enhancement will be pointed out. A stiffness program for prediction of shock tube stiffness, as determined by the stiffness of the individual layers, will be presented and discussed.

Jan 1, 2010

By Yoshihiro Moriyama, Toshihiro Okitsu, Ryouichi Banno

The fracturing composition using the gas pressure generated by the thermit decomposition reaction gives the following performances.

Jan 1, 1995

By John M. Bolger, Keith E. McMaster

Excessive salt fines are undesirable in underground salt mining as they are considered a costly waste by-product. This paper describes an extensive explosive application program conducted at The Canadian Salt Company Ltd, located in Pugwash, Nova Scotia, Canada. The prime objective of the program was to reduce the quantity of fines generated from this company's underground production blasts. The program was known as the "The Fines Reduction Program".

Jan 1, 1996

By Yessica Idrogo

"Undoubtedly mining is currently the activity that brings a great development for all countries involvedin this industry, which means that to develop mining requires adequate explosive mixtures. The following work about AL/AN/FO is presented, knowing that this is a dry blasting agent, which iscomposed by ammonium nitrate, petroleum diesel N°2 and aluminum (AN, FO, AL). It is known that this dry blasting agent AL/AN/FO was invented by A. Baver Ph. D. in Marcona Mining Company, 12/12/1968, where in that investigation also worked Carlos Agreda Ph.D. as assistant of the mentioned inventor."

Jan 1, 2017

By Clayton Thompson

Linear detonation wave generators (DWGs) shape a detonation wave so that every portion of the wavefront reaches the target “line” simultaneously. A projection-type linear DWG uses Gurney plate velocity predictions and Taylor deflection angle predictions to estimate the angle at which a thin projected flyer (typically metal) will impact a target. A mousetrap-style planar DWG consists of two projection-type linear DWGs working in succession to create a planar wave-front through shock initiation of each successive target explosive. The angle of deflection is critical to yielding a planar or linear wave profile. Gurney predictions, nominally accurate to within 10% of empirical results, may not yield ideal linear or planar detonation behavior when used with a grazing projection-type DWG, which typically requires accuracy within 2%. Simulations were conducted using AUTODYN hydro code to compare deflection angle prediction methods. Ranges of minimal error between Gurney and Taylor predictions and the results from the hydro code were determined, using PBX-9404-driven polyethylene flyers.

Jan 1, 2011