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By Andrew P. Ritter, Douglas A. Anderson, Stephen R. Winzer

We have adopted a unified approach to blast design. Based on earlier research, we chose minimum relief of 3.4 ms/ft between holes in a row and 8.6 ms/ft between echelons to produce good fragmentation. A model has been created which generates the expected ground vibration frequencies from a particular delay pattern. Within the relief guidelines, blast designs have been created to shift the expected frequencies of the ground vibration above the resonant range of residential structures. A programmable sequential blasting machine was used to delay circuits. An extensive three-month seismic monitoring program determined that this approach is successful. From data collected for over a year, we have determined that crusher throughput is up about 10%, frequency modification has been largely successful, peak particle velocities have generally gone down by a factor of 2, and neighbor complaints have decreased drastically.

Jan 1, 1982

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

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 Dal Sun Kim, Michael K. McCarter

"Comminution (crushing and grinding) of rock materials is energy-intensive and expensive. Mucheffort has been directed to improve the efficiency of conventional milling practice, but relatively littleattention has been given to the potential benefits of blast-induced damage on comminution processes. To help assess this effect, research has been conducted at the IRECO Laboratory and the Generic Center for Comminution at the University of Utah. The objective of this research is to investigate the effect of shockinduced “crack-like” damage on rock properties and subsequent breakage efficiency for three petrologically different rock materials under laboratory conditions. In order to evaluate the effect of shockinduced damage, a quantitative measure of rock damage is needed. For this purpose, a scalar variable (0) is proposed."

Jan 1, 1993

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 Lee Wehner, Daryl Kin, John Bolger

The Maumee Quarry, located in the city of Maumee, Ohio, has large in-situ cavities, ranging in size from 3 ft (.91 m) in diameter to over 15 ft (4.5 m). The drill/blast team challenge is to drill, load and shoot the geologically disturbed rock in a safe, cost efficient manner, while in close proximity to a commercial area. A continuous improvement process, managed by a Blast Optimization Team (BOT), was implemented to quantify the innovative explosive loading techniques that have been implemented. Borehole camera monitoring, modified loading practices, the need for accurate drill hole logging and open communications between the drill and blast crew proves critical to the success of the operation. Safe Standard Operating Procedures (SSOPs) have been developed and are strictly enforced for the drill/blast cycle. All blasts are monitored with seismographs and recorded on video to provide detailed information as part of the Blast Management Plan. Despite the geological challenges, the measurement of rock fragmentation index versus loader dig rates has provided near optimal crusher throughput.

Jan 1, 2007

By Y. Idrogo

Electronic delay detonators have been used in most types of blasting application with great success, with the accuracy and precision being used effectively to control negative environmental impacts like vibration. They have also provided consistent repeatable fragmentation and heave results. With the very wide choice in delay period and powerful timing design software, the choice of firing times to optimise blast results is not always clear to the designer. So the improved results achievable from the use of electronic delay detonators are often not optimally achieved.

Jan 1, 2018

By Robert A. Cummings, Francis S. Kendorski, Charles H. Dowding

During the summer of 1980, a field project was carried out to determine the stability of the beautiful and dramatic natural limestone pinnacles (locally termed "Hoodoos") at Bryce Canyon National Park, Utah, when subjected to ground motions and airblasts resulting from proposed strip coal mine blasting. The concern arose from environmental considerations associated with the proposed development of a large coal strip mine which would approach within 4 miles of the park. The pinnacles range up to 150 ft in height and are quite slender, producing a fragile appearance. The remoteness and ruggedness of the area required a field camp, and 4-wheel drive vehicles, helicopters, and snowcats for support. Portable magazines were necessary to store the more than 7 tons of blasting agents and explosives required. In conducting the blasting, great attention was paid to environmental impacts. In the field, a target pinnacle was selected and instrumented with mechanical strain gages, and research seismographs that required helicopter placement.

Jan 1, 1982

By Alastair Torrance, Braden T. Lusk, MinGi Seo, Gary Cavanough

Velocity of Detonation (VOD) is the most commonly used method to determine explosive performance as VOD is a function of the confinement (ground conditions) density and composition of the explosive. Techniques used to measure VOD include resistance wire, time domain reflectometry, simple start stop and fibre optic methods. All these approaches require a cable of some sort to be inserted into each blast hole being monitored and the holes to be fired in a specific sequence. It is time consuming and fairly technical to position the cables correctly to gather the data from each hole. It slows down the hole loading process and increases the number of people on a bench at that time. The equipment and cable limits the measurements to a few holes, typically 5 or less, that are in close proximity. These measurements can generate useful information about the monitored holes but does not provide a full picture of how the explosive is performing across the whole blast and whether any change in performance is noted with changing ground conditions or confinement.

Jan 1, 2019

By Paul Worsey, Seokbin Lim

In many high explosive applications, the explosives are covered or clad by a metal. This metal cover may serve a variety of purposes including: 1) to protect and prevent the disturbing or misshaping of the explosive during its transportation, handling and use, 2) in many military applications the cover material itself is used to provide a required effect, for example, the shrapnel from grenades, the metallic liner of shaped charges, and the confinement of explosives so they perform optimally, and, 3) in civilian applications in the use of well perforating shaped charges and linear shaped charges used for the demolition of steel structures such as bridges. For these reasons the interactions between the explosives and their covering materials are of great importance in understanding the performance of these devices.

Jan 1, 2005

By Richard J. Mainiero, Eric S. Weiss

This project investigates the behavior of blast waves from the detonation of high explosives in an underground mine. A series of explosive tests was conducted in the underground and surface facilities at the Bureau of Mines' Lake Lynn Laboratory to evaluate the potentially dangerous effects of blast waves produced by open shooting, blown out holes, or accidental detonations of explosives. Shots of C4 and TNT were fired at the dead end of a 6 ft high by 20ft wide entry, at the intersection of two entries, and on the surface. C4 and TNT were chosen for this research because they exhibit very consistent performance. Behavior of the blast wave was evaluated through recording of the pressure as a function of distance from the explosive detonation.

Jan 1, 1995

By Amund Bruland, Vegard Olsen

This paper presents analytical assessments around unintended misfire detonation, within rock debris drilling and bench top cleaning, primarily in the quarrying and mining industry. The main purpose of the work has been to see which operation has the lowest fatal accident probability. To be able to do this a risk analysis model is developed and the basics of the model are described first in the paper. Further a practical approach of the model use is presented. This includes a summary of general fatal injury statistical data, which is used to establish input parameters in the model. The result of the work shows that the rock debris drilling operation has at least half the probability of fatal injury compared to bench top cleaning. The result of the work should bring along rewriting of the Norwegian explosives regulation. The statistical data also shows that the blasting industry generally has a high fatal injury rate compared to other industries and basic risk reference levels. Risk reduction efforts concerning the examined operations are described.

Jan 1, 2008

By Henry P. Jr Van Ormer

During any blast hole operation the first choice to be made is hole size - it seems simple, just calculate all the factors, spacing, burden, depth, rock characteristics, powder factor, etc. and you have it - Hole Size. But we all know that it is not that easy - the "hole size" is part of a system and many other situations can have great impact on the optimum production Blast Hole Size - such as crusher characteristics, hauling capability, mucking capability and - Drilling Capability!

Jan 1, 1983

By Shazad Hosein, Bill Birch, Catherine Johnson, Toby White, Liam Bermingham

Air overpressure (AOP) from blasting can give rise to a significant number of blasting complaints from residents living adjacent to blasting operations from mines, quarries or civil engineering projects. High amplitudes of AOP are usually associated with the lateral movement of a vertical free face, but it can also be caused by the upward lifting and the venting of gases through the surface of the blast area.

Jan 1, 2018

The underwater explosions have been used for several decades for the determination of energy content of explosives. This test method is the only one by which shock, fly rock and total energy can be measured separately. It enables to develop the energy content of explosives for different purposes; the military high explosives should contain more shock energy whereas the fly rock energy is very important feature for the blasting explosives. The purpose of this study was to establish a test place for the underwater experiments in an old water filled open pit, to estimate the repeatability of the energy measurements, to calculate the standard deviations and to compare the total energy content of commercial explosives to the theoretical values calculated by the thermo dynamical program. The test method seems to work quite well especially for the homogeneous explosives. The difference between the energy content of theoretically calculated and measured values for the homogeneous emulsion explosives was about -3% and for the dynamite about -5%. The energy difference for the unhomogeneous ANFO was detected to be -19%. The diameter of the charge was 15 cm and it was obviously too small for ANFO to detonate ideally. On the basis of the test results this test method seems to fit best for the cap sensitive, completely homogeneous, spherical charges whose masses are big enough and which are initiated from the centre of the charge. The underwater explosions as a test method is the only one which can separate shock, bubble and total energies from each other and therefore makes it possible to develop the properties of explosives for different purposes which is very important feature of this method.

Jan 1, 2005

By Chick Kerkering, Stephen Iverson

Perimeter control blasting is common in civil construction projects but not as common in mining. A poorly designed and executed underground mine development blast design can result in unwanted wall rock damage. This damage increases the risk of rock falls and injury. With the availability of good drilling equipment, it is a simple matter to add the few extra holes needed to change conventional drifting into drifting with perimeter control.

Jan 1, 2008

By Jung-Hoon Ryu, Chang-Ha Ryu, Byung Hee Choi, Yang-Kyun Kim

Control of overbreak in tunnel blasting is one of the key factors affecting the construction expenses as well as safety. Overbreak causes an increase in the cost of construction by requiring an additional amount of shotcrete. In addition, blast damage to the final rock face may cause instability and rock fall hazards. For these reasons, controlled blasting is an indispensable routine in tunnel excavation in order to get a smooth face and to reduce damage to the final wall. We have experienced a very poor quality of excavation depending on the tunneling sites although a similar design of controlled blasting technique was applied. Field experiments over 40 rounds were carried out to investigate the cause of the poor results in tunnel blasting. In this paper, discussed are the parameters affecting the overbreak and some findings from the field experiments. Overbreak could be controlled considerably by adjusting some parameters before the efforts of developing a new blasting method.

Jan 1, 2004

By S K. Mandal, S Dasgupta

"Damage is classifi ed as loss in the integrity or deterioration in the quality of rock massand is infl uenced by methodology of excavation on the geo-technical properties of rockmass. Overbreak, on the other hand, is the result of damage and is quantifi ed in either of the terms viz., extra mucking, shot-creting, application of extra support system and extension of scheduled completion time. Damage or overbreak in rock mass by the impact of blasting, is generally unavoidable but, the magnitude can be minimized so that it does not deteriorate the quality or integrity of structure. The paper, here, analyses magnitude of overbreak of a powerhouse cavern with respect to different blast patterns implemented at the site. The magnitude of overbreak was analyzed in terms of profi le measurement with the help of laser profi ler and percentage of halfcast markings observed on the periphery rock wall. The paper revealed the impact of decoupling ratio, blast pattern and geometry of blasting patch on the magnitude of overbreak. The authors observed that presence of un-favourable joint pattern or foliation plane along the periphery rock wall couldn’t contain magnitude of overbreak within allowable limit. The analyses revealed that percentage of half-cast markings on periphery rock wall was infl uenced by response of rock towards detonation of explosive and cannot be a single parameter to assess the effectiveness of a blast. The analyses also revealed that magnitude of overbreak for down-stream wall was more than that observed in up-stream wall."

Jan 1, 2008

By Jennifer Paukula, Steven Lindsay, S. Joon Kim

String loading is the placement of a bead or ‘string’ of emulsion along the lower edge of a development drill hole. The loading hose extraction rate controls the amount of emulsion placed in each drill hole. This allows a controlled distribution of explosive energy throughout the development round. Center holes are loaded using the slowest extraction rate causing the majority of the explosive energy to be placed in the center of the round. The loading hose is extracted successively faster for the buffer and perimeter holes causing less explosive energy to be placed near the edge of the blast. This causes less damage to the rock mass that remains in place after the development blast.

Jan 1, 2012

By Martin Schrier

This paper is an overview of a granite quarry cleanup near Kirkland Lake, Ontario, Canada. A combination of local geology and previous subpar blasting techniques led to the quarry needing significant rehabilitation before it could proceed with general operation. Advanced technologies were implemented into the blasting process, including laser profiling, bore-hole tracking, and geometric timing. The contract consisted of two floor shots and two 25,000 tonne (27,558 US ton) production shots.

Jan 1, 2018