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By W. J. Birch, R. Farnfield

All shock-tube based initiation systems have a time lag relating to the propagation velocity of the shock-tube itself. This paper examines the exploitation of this inherent time lag to achieve delay blasting with accuracies approaching that achievable with electronic systems albeit over a much shorter delay range. The system employed consists of a combination of standard shock-tube, plain detonators and various shock-tube branching components. The accuracy of the complete system depends on the scatter in delay time induced by each component. In order to quantify this scatter a series of trials were undertaken to determine the variability for each component. These trials are described along with a detail statistical summary of the data recorded.

Jan 1, 2009

By J T. Schamaun

Recent applications of explosives and blasting agents to rubble rock have led to requirements for more elaborate design and analysis methods. In most blasting uses, it is necessary not only to fracture the rock, but also to move the broken rubble in a predictable manner. Many in situ extraction techniques require; rubblization to take place in a confined region where rock motion is a predominate factor in creating a permeable broken bed. In this paper, an engineering model is presented which describes the large rubble motion during blasting. This model is intended to provide the blast designer with a tool for evaluation and further refinement of blasting patterns and timing sequences.

Jan 1, 1983

By R Heater, G Glynn

Various small diameter commercial grades of slurry and emulsion explosives were tested and compared. Velocity diameter curves for confined and unconfined charges were established and the effects of temperature and hydrostatic pressure on critical diameters and minimum primer weights were determined.

Jan 1, 1984

By AJ Rorke

Blasting trials using Daveytronic Electronic Delay Detonator systems (EDD’s) were conducted at the Alpha Ferro Quany (Pretoria) and the Eikeboom Colliery near Witbank in November 1999. The objectives of the trials were to determine the influence of accurate hole firing on rock fragmentation, blast-induced vibration and blast throw. This paper provides an outline of the trials and an analysis of the results. The results were compared with a normal shock tube initiation system. Fragmentation was measured using video-imaging techniques at the hard rock Ferro Quarry for one conventional shock tube blast and two EDD blasts. No significant difference was measured in the fragmentation between the shock tube blast and the two electronic detonator blasts. Joint planes mostly defme the fragments at Ferro Quarry. The fragment sizing was therefore controlled mainly by the rock structure and the blast timing appeared to have no influence. Vibration measurements made at Ferro Quarry indicate that electronic detonators have a marked effect on vibration frequencies compared to shock tube systems. The more accurate detonators resulted in a narrower f+equency band at lower amplitude with similar timing. By modifying the blast timing, the dominant frequencies were changed. The electronic detonators had a significant positive influence, therefore on blast vibration and its control. The timing scatter measured from the shock tube blast was considerable, with measured inhole detonator scatter at 48 ms over a sample of 19 units. Surface delay periods less than 42 ms would therefore not be able to provide effective sequential firing. The scatter of the Daveytronic units was below the 2 ms resolution of the high-speed camera used to film the blasts. Reliable sequential firing, even at very short delay intervals was considered the main reason for notable improved throw in an overburden blast at Eikeboom Colliery. Blast throw was improved by 25% for the test blast.

Jan 1, 2000

By Uli Leiste

Two papers are presented which examine Air Deck Blasting, one from a computational aspect and the other from a shock aspect.

Jan 1, 2016

"Large scale open pit mining and quarrying operations dictate safe and reliable pit wall stability. The current approach of employing the particle velocity-scaled charge distance approach to estimate and minimize damage to residential structures is considered inadequate to protect rock slopes. This study utilizes close-in blasting vibration data as input to an advanced 2D numerical code to study its applicability to serve as a predictive tool in terms of blast-induced rock slope failure. Two tri-axial accelerometer stations, consisting of high-frequency and high-amplitude (20 kHz, 100g) sensors, located within ~100m of the blast, but at two different bench levels, were used to monitor a production blasting in a quarry. The production blast consisted of double-decked explosive loads in 155 mm (6 in) diameter holes, with an inter-deck delay of 42 ms, and each deck consisting of 130 kg (285 lb) of emulsionexplosive. The blasting vibration data obtained at the two bench levels were critically analyzed, and thevibration results served as input to the numerical model consisting of a single rock block with a 45 degree persistent joint plane but with specified strength properties, significantly different from that of the intact rock. The model was able to characterise progressive accumulation of damage in the form of micro-cracks along the joint surface as a function of the vibration load from successive explosive decks. The results showed that such a numerical model can serve as a very good diagnostic and predictive tool, when backed up by careful vibration monitoring and further supported by detailed slope monitoring."

Jan 1, 2017

By P A. Lang, J G. Ayotte, R W. Humphries

Atomic Energy of Canada Limited (AECL) has the responsibility for research, and development of technologies, for the safe and permanent disposal of Canada's nuclear fuel wastes. As part of this comprehensive program, AECL is constructing an Underground Research Laboratory (URL) near Lac du Bonnet, Manitoba, to evaluate aspects of the concept of waste disposal deep in stable geological formations. No nuclear wastes will be used in the URL program.

Jan 1, 1986

By A. K. Sirveiya

A major concern with blasting at surface mines is generation of ground vibration, air blast, flyrock, dust & fume and their impact on nearby structures and environment. A study was conducted at a coal mine in India which produces 10 million tonne of coal and 27 million cubic meter of overburden per annum. Draglines and shovels with dumpers carry out the removal of overburden. Detonation of 100 tonnes of explosives in a blasting round is a common practice of the mine. These large sized blasts often led to complaints from the nearby inhabitants regarding ground vibrations and their affects on their houses.

Jan 1, 2005

By John C. Didlinger, John L. Didlinger

As we begin the pre-blast survey we need to decide on the number of holes needed for production and a detailed highwall inspection. The survey consists of checking the highwall and placement of barrier cones. At the Elmhurst Chicago Stone Company, Barbers Corner Plant, we use 18-24" orange highway type safety cones. These cones are easily noticed because of their high visibility color in all weather conditions and are placed approximately 20-25 feet from the face and approximately 50 feet apart along the highwall, then the area is checked for back break, under cut, over hang, surface filled area and clay area. This deposit is unique because of the number of clay filled areas and slip seams that meanders through the deposit plus a fault that runs North-Northwest and South-Southeast. This particular limestone deposit is overlaid with glacial sand and gravel and the top weathered stone wanders plus or minus 10 feet in 1400 feet.

Jan 1, 1996

By Sarah Guzzelli, Enrigue Munaretti, Anneliese Botelho, Jair Koppe

Drill and Blast (D & B) is one of the main operations in the mining production cycle, which aims to fragment rock according to a pre-defined plan for proper loading, haulage and processing specifications. In this sense, data from a Brazilian iron ore mine was analyzed, given emphasis on blasthole length, subdrilling and stemming. The D & B report, including mining data such as number of blastholes, length, and diameter and stemming aspects, was analyzed in order to be able to compare these results with the blast design. The study showed significant differences between the designed blasting pattern and that one obtained by the operation. As a consequence, problems such as inadequate fragmentation, incorrect size distribution and loss of energy, were identified. For example, when stemming has a different length than it should have, noise and flyrock can occur, including inadequate fragmentation and vibration in both situations. Therefore, a comparison between the usual D & B procedures and recommended D & B design based on literature reveals the most important deviations and their consequences. The study intends to identify solutions for simple problems, improving D & B operations and safety practices.

Jan 1, 2014

By Gungor Tuncer, Ali Kahriman, Umit Ozer, Abdul Karadogan, Mehmet Aksoy, Ertugrul Kaya, Deniz Adiguzel

This research was performed on the quarry that will be opened to produce aggregates and rock filling material at Catalagzi region at Zonguldak providence. Excavations will be done by drilling and blasting. However, there are some structures which can be adversely affected by blasting at the quarry. These structures are a methane exploration drill hole and a house at the distances of 340 m and 390 m, respectively. The one of the main goals of this study is to perform a preliminary assessment of possible damage effect of ground vibrations induced by blasting on these structures by risk analysis based on ground vibration measurements.

Jan 1, 2009

By Chuck Kliche, Bill Clements

This project involved the removal of the top of an old water supply reservoir tank for the City of Lead, SD by explosives. The general contract called for the removal of the concrete top without damaging the sides or floor of the reservoir. The option of a rock hammer was eliminated, due to the possibility of an unpredictable collapse damaging the sides or floor of the reservoir. Different blasting options were discussed between the primary contractor and the blasting contractor, along with the pros and cons of each. The primary contractor settled on the option of drilling the structure for blasting versus using shaped charges

Jan 1, 2007

By Dave Harrison, Phyllis Hasser, Ken Eltschlager

The beginning There was the video:– “Understanding Vibrations from Blasting” – 2002 to 2004 in development – Dale Ramsey ad hoc Public Education committee chair – Available At the ISEE bookstore Public Education and Public Relations Committee • Standing ISEE committee 2004 • Co-Chairs – Ken Eltschlager, Dave Harrison • Purpose: "Develop and conduct programs on public education and public relations. Public education programs will focus on public awareness, understanding, and appreciation of the explosives industry. Public relations programs will concentrate on providing blasting professionals with the tools to assist in the public's understanding of the explosive industry and in the appropriate ways to respond to local community issues."

Jan 1, 2007

By James Goldberg, Sally Zadra, Wiliam Reisz

Early recognition and risk assessment is critical to sustaining a safe and productive blasting operation. While every blasting environment holds inherent risk, highwall blasting in highly congested areas such as Hanson Material Service Corporation’s Romeoville and Thornton quarries in the greater south Chicago metropolitan area can be particularly perilous

Jan 1, 2008

By Abdulkadir Karadogan, Zikri Keti, Umit Ozer, Mehmet Aksoy, Ulku Kalayci

This paper presents an investigation about how the motions of blast induced vibration waves were affected by the presence of the fault planes. This study was carried out at Espey Open- Pit Boron (Colemanite) Mine in Turkey. Within the scope of the study, ground vibration components were measured for 8 shots using 9 vibration monitors, considering the direction of the fault. Measurement stations were located around the fault line that intersects the open-pit mine in the north-south direction and on different benches along the fault plane. Then, the data of the vibration components obtained from the 77 recorded events were analyzed and the results were presented.

Jan 1, 2012

By William H. Snyer, Victor A. Sterner

A cache of buried explosives was discovered by ICI Explosives, USA Inc. at one of their sites near Gillette, Wyoming. An intensive investigation conducted by ICI management indicated that nitroglycerin sensitized dynamite might be present. Information also indicated that up to 20,000 pounds of explosives may have been buried.

Jan 1, 1997

By Robert L. Martin, Brian W. Stump

"The Black Thunder Mine is located in the Powder River Basin of Northeastern Wyoming. Over 39.2million tons of coal were produced at the Black Thunder Mine in 1996. Just over 100 million pounds ofANFO/Emulsion blend were consumed in that same year. Currently around 30% of the overburden is cast to final with the use of explosives. With plans for a mine expansion, explosives will continue to play a very vital roll well into the future."

Jan 1, 1997

By Jeffrey W. Lin, Jonathan D. Abbott, Patrick R. Bowden, Tyson J. Plitt

Pentolite is a class of high explosives containing trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN) with PETN content typically ranging from 40 to 60 wt%. Manufacture involves melting TNT, 80 °C, followed by addition of PETN and trace ingredients to form a homogeneous mixture. Once a mix is ready to be poured, several factors can influence the behavior of the finished product including how long the mix has been at temperature and cooling rate. After the manufacturing process has been completed, storage conditions combined with manufacturing conditions may cause physical changes. Two such changes explored were exudation, liquid exuding from solid boosters, and ratchet growth, irreversible volumetric expansion. Exudation is principally caused by excess water in the process. Ratchet growth is a common phenomenon of nitroaromatic compounds such as TNT where time and temperature fluctuations can cause materials to increase volume, simultaneously decreasing density. Although neither phenomenon affects common attributes such as sensitivity, performance, and shelf-life, both can cause issues in storage and handling. In this study pentolite was cast into various forms under different manufacturing conditions and evaluated over several months of controlled storage conditions including ambient, temperature cycling and elevated isothermal. Subjective and objective measurements were made throughout the evaluation period with the aim to determine the preferred storage methodology.

Jan 21, 2025

By John N. Jr Edl

Geokinetics, Inc. has pioneered an in-situ oil shale retorting production process that provides the requisite void space for producing a permeable rubble bed, within the retort zone, by using the explosive energy from vertical blastholes to lift the overburden. By installing suitable instrumentation on the surface of the overburden over an appropriate blasting pattern, it is possible to obtain estimates of the average radius of gas penetration around the blasthole and the average volume, per unit length of blasthole, that is actually occupied by the explosively produced gases (which includes both the volume of the cracks that are penetrated by the gas pressure and the deformed blasthole volume). It is expected that these estimates can be used to examine, and quantify, the effects of such blast design parameters as the type of explosive, the blasthole diameter, the geometry of the explosive charge (length to diameter ratio), and the relative timing of sets of charges.

Jan 1, 1983

By Zheng Deming, Li Hongwei, Lei Zhan, Dai Chunyang

This paper introduces the application of a digital electronic detonator in the demolition blasting of largescale (LS) and long delay time (LDT) frame-shear structure buildings. The whole building to be demolished by blasting is an L-shaped frame shearing structure. Some parts of these buildings have a large length along the direction of collapse, so the detonation delay of the column is longer. To ensure the building is successfully blasted and demolished, a digital electronic detonator detonation system is adopted. In the design of the detonating network, full use is made of these characteristics of the digital electronic detonator, such as flexible installation, high precision of delay before blast, and dedicated testing equipment to check the reliability of the network. These advantages ensure the damage of the load-bearing structure is within the blasting gap and that the accuracy of the collapse time of the building, which not only guarantees the collapse effect of the building, but also provides strong technical support for improving the intrinsic safety of the blasting operation and the supervision of the flow direction of the detonation, these research be provide reference for the application of digital electronic detonators in similar projects.

Jan 1, 2019