Search Documents

By A. Karadogan, G. Tuncer, A. Kahriman

Determination of optimal blast parameters have been the priority act for blasters on the field due to financial and technical properties of the operation. Therefore many researchs were done to establish a general formula for many years. These intends could reach some empirical and numerical design frames consisting the rock, geology and explosives properties. Blasting parameters have to be adjusted according to the desired fragmentation rate especially on the mines where particle size distrubition after blasting has a great importance. Therefore the blast designs have to be evaluated considering the particle size distribution after the blasts. The Kuz-Ram model which was modified by Cunningham is one of the tools for estimating the particle size. Although it doesn’t give an accurate result, it can be very succesful on modifying the blasting design parameters by establishing a back correlation between the blasting parameters and the exact particle size distribution results which can be easily achieved by digital image processing system. Within the scope of this study, the particle size distribution after blasting was assessed by Split-Desktop digital image processing system and bench blasting parameters were studied considering the desired particle size distribution at Espey colemanite mine using Kuz-Ram and digital image processing system combination to determine the specific blasting parameters for this site.

Jan 1, 2005

By Frank Chiappetta, Karl Zipf, Robert Hopler, Brian Stump, Francois Heuze, Bob Martin, Vindell Hsu, William Walter, Craig Pearson

The Comprehensive Test Ban Treaty (CTBT) was accepted for signature at the United ,Nations in September of 1996. It ‘now awaits ratification by its signatories, ~including the United States. After the Treaty is in force, the main concern of the international community twill be to verify that no nuclear test is performed.

Jan 1, 1998

By Michael Ostrowski

While the words “explosives” and “blasting” cause insurers to become apprehensive, skilled contractors using modern techniques under controlled conditions rarely cause serious damage or injury. However, blasting operations frequently result in complaints and, consequently, insurance claims. The purpose of this bulletin is to inform construction project participants of some of the measures which may be taken to reduce losses arising from blasting operations.

Jan 1, 2003

By Detnet Solutions

1. “Daisy-Chain” concept The term “daisy-chain” stems from the fact that when the HotShot? detonators are connected there is a chain or electrical path for electrical current to flow from detonator A to detonator B, detonator B to detonator C etc until the path is terminated by an electrical means. The “daisy-chain” concept has long been used in electronic detonator systems, historically used in Expert Explosives’ ExEx 1000 5/6 wire system and currently in use in African Explosives Limited (AEL’s) Electrodet? electronic detonator system and has been adopted as the basis upon which the “auto-programmability” of the HotShot? electronic detonator system functions. HotShot? Detonators are connected to each other in a string, completing a “daisy chain”, and during the auto-detection mode of the control equipment, it is possible for the equipment to determine the order of hookup of the detonators as well as map the entire blast layout. The auxiliary components (Row Controllers & Branch Controllers) assist the control equipment in mapping the entire blast by indicating different points on the blast, i.e. The inflection point of a row of blast holes on a closed chevron timing pattern, the beginning of row of blast holes on open chevron timing pattern and extra blast holes or extra blast rows.

Jan 1, 2004

By Serge V. Krasavin

The behavior of rocks subjected to dynamic loading conditions under explosion includes sufficient information about hydrodynamic variables such as pressure P, mass velocity U, internal energy E, specific volume V and density p as functions of time. Measurement of dynamic characteristics in compressed media with manganin wire sensors has become common in the past few years, but the experimental data for certain media, such as rock, do not provide an exhaustive description of rock's behavior in the near zone of an explosion, which is highly responsible for the transformation of energy of explosives.

Jan 1, 1992

By Qi Shifu, Guo Tao, Liu Haoquan, Yao Chaogui, Zheng Li

Abstract: To excavate oil-gas pipeline ditches in a rocky region or area the explosive method is needed. When a parallel ditch is to be dug by blasting near or in the vicinity of an existing pipeline, a safe criterion must be determined to ensure safety for the latter. In this investigation, with the construction of the second phase of the West-East Gas Pipeline Project, we carried out real blasting tests and numerical simulations to explore the safety criteria for the existing pipeline. Through this investigation, we obtained the safe strain elasticity threshold es2000µe, blast vibration velocity calculation formula, and the maximum vibration velocity Vmax=14cm/s(5.51in./s) for the pipe under blast shock loading, and worked out how to determine the charge size in the follow-up blasting excavation. These results can be used to determine the maximum explosive weight per delay and decide delays for the initiation circuit network in blasting a parallel pipeline ditch, and to make safety assessments for the existing pipeline in service. Having successfully been applied in the second and third phases of the West-East Gas Pipeline Project, China-Russia Oil Pipeline Project and China-Myanmar Gas Pipeline Project, these findings are very significant for other similar pipeline construction.

Jan 1, 2014

By W B. Gregg

The rock blasting and mining industries use a system of detonators and explosives for mining operations. Many detonators use small metal bridgewires, which are heated by passing a current through the wire, heating and igniting the pyrotechnic powder in contact with the wire. Typical bridgewires require a current of at least 3 amps, applied for a few milliseconds, for an explosive output. The semiconductor bridge (SCB), in comparison, initiates an explosive in 0.01 to 0.1 of a millisecond.

Jan 1, 1994

By Chen Jianping, Wu Li, Wei Banyun, Chen Canchang

Liquified petroleum gas mixed with oxygen has been used as a new type of mixed gas source for gas detonating system. The experimental studies have been done on the detonation feature of gas detonating transmission in a long and thin tube, the transmitting reliability for detonating network, the design on gas exploder and test devices. The results of the study show that (1 )Liquified petroleum mixed with oxygen can be used as a new type of regular gas source. (2)The transmission of detonating wave is reliable for new type of mixed gas in a 500-meter long plastic tube with 3mm inner diameter and the detonating velocity is up to 2500m/s. The detonating wave can surely initiate and transmit several branched gas detonating cap and explosive through the end of detonating network, the tubes inner diameter for the detonating quenching is 0. I’mm. (3)The gas exploder designed by authors can be used for gas propotional distribution,strong turbulence-mixing,initiating by reflex shock wave and safety control purposes. The developed double flowmeter can be used together or seperately in responsible for main testing in the system.

Jan 1, 1999

By R. Reed Skaggs, William Gault, Douglas Kooker

Both armored personnel carriers and light combat vehicles are increasingly vulnerable to a variety of highly lethal antitank land mines. As a result, there is a need for modeling and understanding the interaction of mine blast products with respect to the resulting loading and damage mechanisms inflicted by explosive blast and impact on vehicle structures. However, the mechanics of blast soil interactions are still poorly understood. The objective of this investigation is to computationally simulate a series of experimental buried mine explosions in saturated sand soil -- over a wide range of scale – and compare the predictions of blast loading to data. Small scale tests have recently been conducted at the University of Maryland with a few grams of RDX acting against an aluminum plate, while recent full-scale tests at ARL involve several kilograms of TNT against 12,500 kg of RHA. The ARL measurements reported here are based on the Vertical Impulse Measurement Fixture (VIMF) facility, a structural mechanical device that responds to blast loading by measuring the vertical displacement of a fixed mass vertical guide rail, which is a direct measure of the imparted impulse. CTH predictions for vertical momentum of the target plate are within 60 – 80 % of the reported impulse data for this wide ranging set of tests. One of the comparisons, however, suggests that the TNT charge in a particular VIMF test may not have fully reacted.

Jan 1, 2005

By Donald F. Rapp, Thomas E. Brown

The application of commercial explosives in an underwater environment, sometimes referred to as submarine blasting, presents the blaster with a unique set of demanding conditions which require exacting detail in design and application. There are two basic methods for removing rock under water: 1) "the drill and blast method"; and 2) "the dobying method." Because it is a far less effective method of blasting, dobying will not be addressed in this 'paper but suggested criteria can be found in the 16th Edition of the **DuPont Blasters' Handbook" page 371. Some examples of submarine blasting utilizing the drill and blast method include channel expansions, harbor construction, bridge pier footer excavations, utility excavation and demolition work.

Jan 1, 1994

By George P. Jr Schivley

Looking at the process of drilling rock from the standpoint of the power required, yields an equation that relates Force-on-the-Bit; Torque, to rotate the bit; and bit Angular Speed to the Penetration Rate of the bit; the Area of the hole being drilled and the Specific Fracture Energy of the rock. Specific Fracture Energy and the Compressive Strength of the rock are related.

Jan 1, 1994

By PHILIPP HARTLIEB, Peter Schimek, Thomas Seidl, Paulo Couceiro, Pablo Segarra, José A. Sanchidrián, Juan Navarro

This paper describes a new methodology to assess rock mass-quality to guide blasting in open pit operations. A developed Structural Block Model and Strength-Grade factor have been combined in a Rock Factor, that, exclusively obtained from drilling data, can provide an automatic assessment of rock structure, strength, and waste/ore identification.

Feb 1, 2020

By Robert Hopler

It is the nature of the initial detonation to the powder around the cap which governs the greater or less effect of the explosion of the whole charge. The cap communicates to the first particles of powder a disruptive impulse, which, according to the nature and strength of the cap, more or less completely overthrows their equilibrium and decomposes the powder with great energy, setting up sympathetic vibrations that explode the particles of powder in turn by the violent disturbances or friction between them in a regular succession of impulses and decompositions, which, if started with sufficient energy, are of such intense heat and velocity that the rupturing force of the explosive is developed practically instantaneously. This detonation has already been shown to be not only the result of mechanical force, but a combination of extremely sudden chemical and dynamical reactions which set up vibrations to which different powders are more or less susceptible, and these explosive reactions will be propagated through the mass of the powder according to the intensity of the vibrations and the resistance with which their motion is opposed by the nature and consistency of the powder, whether it be difficult or easy to oxidize, soft and plastic like dynamite, or hard. If the initial detonation of the powder surrounding the cap is of the highest degree, the vibrations will be most intense and will be propagated further through the mass than by a poorer detonation. Hence the different degrees of detonation. Unless the first particles of powder are so thoroughly decomposed by a detonation of high order, or first degree, as to convey the necessary heat and energy to detonate the whole charge, the greatest force of the powder will not be developed. There will frequently be unbottomed holes or pieces of unexploded powder scattered about, or both, and the air in the mine will be contaminated with some obnoxious gases that have not been completely oxidized.

Jan 1, 2007

By Thierry Bernard, Pierre M. Vuillaume, Michel Kiszlo

"In the context of its studies for the trench ministry of the environment and for the French national coal board, INERIS (the French institute for the industrial environment and hazards, formerly CERCHAR) has made a complete critical survey of the methods generally used to reduce the levels of blastingvibrations."

Jan 1, 1996

By Brian W. Stump, David P. Anderson

Identification of seismic events detected under a Comprehensive Test Ban Treaty requires a clear physical understanding of the different types of seismic sources including mining explosions, rock bursts, mine collapse and small, shallow earthquakes. Constraint of the operative physical processes in the source region and linkage to the generation of seismic waveforms with particular emphasis on regional seismograms is needed. In order to properly address the multi-dimensional aspect of data sets designed to constrain these sources, we are investigating a number of modern visualization tools that have only recently become available with new, highspeed graphical computers that can utilize relatively large data sets. The results of this study will provide a basis for identifying important physical processes in the source region that contribute to regional seismograms.

Jan 1, 1995

By V. Wetzig

In the past, various investigations have been carried out at the Hagerbach Experimental Gallery under accurately reproducible conditions, in order to determine the emissions emanating from blasting operations. Comparative investigations proved that the composition of the blast fumes is influenced by the choice of different explosives. It also emerged that the use of emulsion explosives leads to significantly lower concentrations of harmful substances in the blast fumes. Further investigations concerned the residues and reaction products from the explosive process which are left in the debris. Eluate tests on representative samples of debris were used to determine the concentrations of nitrate, nitrite and ammonium in the debris.

Jan 1, 2001

By Rennie Kaunda, David Streeter, John Kemeny

This paper describes a field/laboratory study that was conducted in cooperation with a mine in Arizona. The primary purpose of the study was to investigate the effect of blasting energy on the crushability and grindability of the post-blast rock fragments. The crushability and grindability of the rock fragments were evaluated through laboratory comminution tests. A secondary purpose of the study was to investigate different laboratory methods for estimating the comminution properties of the rock fragments. In particular, a number of standard rock mechanics tests were conducted and compared with the comminution test results. Finally, the study was used to evaluate new technologies for estimating insitu rock mass strength and for assessing post-blast fragmentation. To estimate in-situ rock mass strength, the specific energy of drilling (SE) was calculated during blast hole drilling utilizing a continuous drill monitoring system. Post-blast fragmentation was estimated using the Split image processing system. Results from the study support the idea that increases in blast energy can enhance crushing and grinding. Also, several simple rock mechanics tests were found to correlate well with the results from standard comminution tests, which could prove to be useful in practice.

Jan 1, 2003

By Rundqvist

The best method to minimise disturbances from traffic to the neighbourhood and in Urban is probably to go underground. For obvious reasons this will cause vibrations, noise and other environmental effects which need very strict regulations and quality assurance in order to complete the work successfully. One project is “Southern Link”, a part of a ring road system. The system of tunnels includes 16 kilometres of tunnels right beneath the south part of the city of Stockholm. At least 20.000 people will be or could be affected by different kinds of disturbances and pollution such as vibrations, noise, gas and groundwater. Another project is the “Arlanda Link”. A new railway with three stations has been built under the existing and running to Arlanda airport with its terminals. Authorities have carefully judged these projects, which cause complaints from neighbours due to disturbances. The blasting operations are professionally managed by the contractors and controlled by consultants to keep the regulations according to the Swedish standards, which are well described in the tender documents by risk analysis and technical descriptions. In spite of that, one conclusion is that it is not always possible to go underground without exceeding stipulated regulations with existing technique. Some of the regulations also double the cost of excavation

Jan 1, 2001

By Ed Clah, Catherine Aimone-Martin

The vibration response of a 30 in. diameter high-pressure (845 psi) natural gas pipeline to 11 coal mine blasts was measured. The X-52 steel pipeline was buried 7 ft. below the ground surface. Ground and pipeline motions in terms of velocities were recorded on the pipeline, in the ground adjacent to the pipeline, and near the ground surface directly above the pipeline. These data were used to estimate the maximum stresses and strains in the pipeline occurring during the blasts. Pipeline standoff distances varied from 264 ft. to 3720 ft. Two blast hole layouts and timing schemes were used. One represented highly confined blasts to limit movement of the shot overburden that generated high ground motions at the pipeline. The second represented patterns that provided greater relief and lower the ground velocities at the pipeline.

Jan 1, 2003

By Robert Hopler

The use of electrical fuzes is rapidly superseding the old cap and fuse method of firing blasts. It is therefore desirable that the details of this kind of blasting should be more generally understood

Jan 1, 2006