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By Shulin Nie

The detonability of a chemically gassed emulsion explosive has been studied in recent tests, after the study of three micro-balloon sensitized emulsion explosives. Blasting experiments in steel pipes and computer simulation have been carried out. This study showed that the gassed emulsion explosive and the micro-balloon sensitized emulsion explosives have different desensitization features. Namely, the gassed emulsion explosive can recover its detonability very rapidly after the pressure vanishes, in contrary to the micro-balloon sensitized explosives.

Jan 1, 1997

By Raymond H. Green, Mitchell W. Green

The authors examined the application of precise millisecond delay electric blasting at a well-known Vermont quarry. The paper explains how the use of a new high-accuracy electric delay detonator has improved fragmentation, raised productivity 10%, simplified blast design, and increased the ability to predict results from blasting.

Jan 1, 1986

By Richard Arsenault

The production of oil & gas from wells requires method of flow from the producing formation into the well bore. Once the well is drilled it will have casing pipe installed to protect the integrity of the well formations and means of delivery to the surface. Once casing pipe is installed it will be cemented in by pumping cement through the annulus of the casing pipe down to the bottom of the well and allowed to flow outside the casing pipe up into the formation.

Jan 1, 2007

By William R. Adamson, Carlos R. Scherpenisse

The successful development of surface mining operations depends, amongst other factors, on the successful creation of final pit walls which offer long term structural stability. The achievement of such walls will be much more feasible if the mechanisms of rock mass deterioration in the mine are well understood, permitting the control and reduction of this deterioration (or damage). The role of drilling and blasting in causing damage is widely accepted but rarely fully quantified. It is also true that the dependence of rock mass damage on vibration levels is only incompletely understood and little accurate field measurement is routinely conducted in the mining industry.

Jan 1, 1998

By Kenneth Eltschlager, Steven V. Crum, David E. Siskind

The Bureau of Mines was funded by the Office of Surface Mining (OSM) to determine how blast vibrations from a local surface coal mine were affecting homes in the towns of Daylight and McCutchanville, located in southwestern Indiana near Evansville. Although Daylight was about two miles from the blasting and McCutchanville four to five miles away, many residents claimed that blast vibrations were damaging their homes. At least one citizen felt that the vibrations worsened at the time the mine began cast blasting.

Jan 1, 1992

In this work, is being described the developing of the study for the demolition by controlled blasting project of a building of reinforced concrete, in the center of a spanish city. Synthetically, it is being analyzed the timing of the fall of the parts of the structure. This documentation is completed with a group of four photographs of the falling sequence and a film about several demolitions and the particular one described in this paper.

Jan 1, 1977

By Mike Koehler

An underground mine that produces aggregate limestone was in operation for approximately eight years when geological changes resulted in dangerous rock falls. The roof in the mine was not bolted; therefore, the drilling and blasting program was called upon to maintain roof integrity. Drilling and blasting were analyzed and modifications were adopted to stabilize the roof. Initial changes were made in the drilling equipment, drill pattern, explosive type, and timing. Any amendments made, after the initial phase, were made individually so it would be easy to discern which changes worked.

Jan 1, 2002

By Kunihisa Katsuyama, Yuji Ogata, Yuji Wada

Test blasting was carried out to study the flying characteristics of rock mass caused in bench blasting. The quantity of explosives was increased from 7.6kg to 9.1kg and the Minimum burden was changed from 131mm to 451mm. The effect of condition for the characteristics of fly rock were considered. The fly rock was observed using the high-speed camera and video to study the flying characteristics of the rock mass caused in the bench blasting. Numerical simulation of fly rock was carried out using DDA (Discontinuous Deformation Analysis) method. It was clear that the DDA method can be applied in the simulation of fly rock caused in bench blasting.

Jan 1, 1997

By Dale S. Preece, J Paul Tidman, Stephen H. Chung

A discrete element computer program named DMC_BLAST (Distinct Motion Code) has been under development since 1987 for modeling rock blasting (Preece & Taylor, 1989). This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in two dimensions (2-D). DMC_BLAST calculations compare favorably with data from actual bench blasts (Preece et al, 1993).

Jan 1, 1998

By RR Vandebeek, A W. Bauer

The Canadian Explosives Research Laboratory regularly evaluates the properties of commercial explosives for authorization under the Canada Explosives Act. Propagation sensitivity is normally measured using small scale tests. Relating the results in actual mining practice is difficult. In the mining industry, the propagation sensitivity is a measure of the ability of one cartridge to propagate to an adjacent cartridge in a borehole. They may be separated by a gap of in-filling material. As well the propagation sensitivity will be affected by the explosive type, temperature, degree of coupling, cartridge diameter and other factors.

Jan 1, 1987

By M Lemieux, R Mason

The SABREX blast modeling program was introduced to I.O.C.C.'s Carol Lake Iron Ore Project in December 1987. As part of CIL's Technical Services, SABREX was used to implement an optimization program designed to analyze and introduce various grades of MAGNAFRAC at a constant pattern while maintaining acceptable blast results.

Jan 1, 1989

By C James Dahn

A new generation of high performance and high density ammonium nitrate prills have been developed. These cycled "prills" offer significant improvement in ANFO mixing time, detonation velocity performance, and heaving capabilities. In addition, their safety characteristics are better than standard ANFO explosives.

Jan 1, 1980

By Zhang Qi

For the most part, the flying piece is serious endangerment in the demolition blasting. To prevent the endangerment, a large number of materials are needed as the protection. Therefore, the determination and design way of the flying distance of piece in demolition blasting have been concerned extensively. Previously, the experienced or half experienced formula was adopted to calculate the distance of the flying pieces. The calculating values of the distances of flying pieces are not identical with the practice results. The problems concerning the design way of flying distance of pieces are researched in the paper.

Jan 1, 1994

By R Mancini, G Borla

This paper analyses the first results of a part of an EEC research project ("Blasting control for underground mining"). This research that involves three universities (Paris, Torino and Leoben) has been carried out at the Eisenerz test mine in Austria. In the experimental campaign here reviewed, parallel holes rounds have been fired "decomposed", which means with enough delay between the explosions of the successive blastholes groups to allow for a separate evaluation of their effects on the rock. The seismic effects have been recorded by geophones placed at small distance from the blast, the aim being to find out correlations between the features of the seismogram and the good or poor performance of the single blastholes, or of the groups pertaining to the same delay. Indeed, the seismogram is the only safe and cheaply obtainable description of what happens during the blast. The seismogram should be transformed in a diagnostic tool in the round 'calibration' stage, and in a routine control device during excavation.

Jan 1, 1995

By K Uenishi, H P. Rossmanith, N Kouzniak, A Daehnke

This contribution presents an introduction into that part of the field of elastic wave propagation which is relevant to blasting of boreholes and addresses briefly borehole breakdown and the formation of the fracture network around a borehole which ultimately leads to the disintegration of the rock mass. Phenomena of this kind are encountered in mining and quarrying. Numerical as well as experimental work referring to stress wave expansion from a detonating borehole is addressed.

Jan 1, 1998

By Donald D. Eilers, Pharis E. Williams, Thomas O. McKnown

The Continuous Reflectometry for Radius vs. Time Experiment (CORRTEX) system was developed by the Los Alamos National Laboratory for determining the energy released in a nuclear explosion by measuring the position of its shock front as a function of time. The CORRTEX system, fielding techniques, and the methods and software for data reduction and analysis were developed over a 15 year period with hundreds of measurements made on nuclear tests and high explosive experiments. CORRTEX is a compact, portable, fast-sampling, microprocessor-controlled system, based on time domain reflectometry, requiring only a 24 volt power source and a sensing element. Only the sensing element (a length of 50 ohm coaxial cable) is expended during the detonation.

Jan 1, 1995

By Geoff Baldwin, Alastair C. Torrance

The use of monitors to assess equipment performance is carried out on a routine basis in many industries. The benefits gained through process control in knowing exactly how the equipment is working far outweigh the initial capital costs of the monitor. In the mining industry several dragline monitors have been developed and installed on equipment through out the world, but to date none has been fully accepted by the industry. This paper describes the use of a sophisticated monitoring system which incorporates an onboard processor to assess both dragline and blast performance. The use of a radio telemetry link for data transfer has removed the need for manual data collection and transfer, leading to a more efficient and powerful system. Significant effort has been put into the development and verification of a dig index to allow blast performance to be objectively assessed.

Jan 1, 1990

By Satish R. Kate

Explosive is a chemical energy, which on detonation is released instantaneously with extremely high speed and under high pressure. It is used to meet the basic requirement for breaking of rocks. The productivity is the function of Drilling, Explosives and Fragmentation. Thus, the quality of explosives (energy content) is the key to get desired fragmentation. The variation in energy of explosives and volume of rock per hole have direct impact on fragmentation and cost of excavation (drilling and explosive costs). With the application of higher and higher energy content explosives, it is possible to expand the drilling patterns, i.e. volume in cum. per borehole. As such, higher drill productivity and higher production from the given number of holes can be achieved by adopting appropriate energy content in explosives, and suitable drill pattern for getting desired fragmentation.

Jan 1, 1998

By Q Liu, P D. Katsabanis

Dust explosions in underground sulphide and oil shale mines result from the detonation of explosives in the blasting operations. Explosive composition, oxygen balance, priming and ideality of detonation were examined theoretically and experimentally in the presence of reactive sulphide dust. It was found that the temperature as well as the chemical composition of the gaseous products of detonation are the controlling parameters related to the explosive. Non aluminized, oxygen balanced emulsion explosives were proven to be relatively safe, while explosives creating combustible products were proven to be extremely dangerous due to the secondary flame they generate. Since a large number of dusty orebodies are often very friable, low density emulsion explosives are also examined for application in production blasting.

Jan 1, 1991

This paper presents a brief discussion of three case histories to illustrate several aspects of the question of blasting in or immediately adjacent to concrete. The results demonstrate a need to make dramatic upward revisions in previous criteria, whether it be the standard particle velocity criteria or damage response spectra bounds, - especially those which include conservative upper limits of constant acceleration for the high-frequency portion of the spectrum. It is demonstrated, also, that conventional off-the-shelf blast-monitoring instruments are not capable of monitoring small blasts at close range. Both the frequencies and the levels of effect are beyond the range of such instruments. These case histories suggest further that there is a need to review the applicability of certain wellknown equations of elasticity.

Jan 1, 1980