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By K Ramachandra Rao

Joints, fractures and other structural defects bring anisotropic character Into a rock mass. Conventional methods of blast design In a rock mass consisting phyllites, mica schist etc., which are characterised by the presence of closely spaced, nearly vertical planar Joints, result In formation of large slabs which cannot be handled by the excavation and loading equipment without resorting to secondary blasting. Frequent secondary blasting Is not only expensive but also, Is a source of environmental hazard. Interruption of production cycles frequently, leads to uneconomical mining. This problem could be minimised by designing blasts which produce forces whose components along and across the joints/fracture planes Is lust sufficient to break the rock mass In both directions. Rock mass strength can be assessed from field and Laboratory tests. Projecting structural features with respect to bench orientation on a stereoplot helps In assessing magnitude and direction of force vectors required to fragment the rock mass to the desired size range.

Jan 1, 1995

By Jesus A. Pascual de Blas

After 30 years of development and introduction, electronic initiation systems are now well established in blasting applications, both mining, quarrying and civil works. In terms of blast technology, it could be considered that timing is the new challenge: how to define the most appropriate sequence to improve fragmentation, reduce vibrations, avoid dilution, eliminate damage… Some classic tools have been updated and adapted to the new scenario, and are giving us good performance; on the other hand, others should be considered obsolete, given the accuracy of electronic initiation systems has exposed these tools to incoherent conclusions. Besides, other tools have appeared and are in use, providing new approaches to old issues. Additionally, not only the technical side has to be considered: safety, security, economics are well present in daily blasting activity and affect to the final decision: are electronic initiation systems the right answer to my blast?

Jan 1, 2019

By Christian Dye

"The following paper focuses on the developing relationship between the members of theInternational Society of Explosive Engineers (ISEE), and the mining students from the BritishColumbia Institute of Technology (BCIT). During the past two years mining students and theISEE members have worked closely in developing a student chapter within the society and onFebruary 1st 2015, the first Canadian Student Chapter was recognized at the annual generalmeeting in New Orleans. This paper discusses the benefits that both the industry and studentsgain with a strong relationship. The mining students recognize the importance for filling the rolesof retiring members of the society and industry. Prior to 2015 the school had only offered a twoyear diploma program in mining and mineral exploration methods. That included a brief sectionin the use of explosives in the mining industry. In September of 2015 students were recruited forthe first ever Bachelors in Mining and Mineral Resource Engineering program. This engineeringdegree includes a full four month course in advanced blasting and rock fragmentation. Studentssuccessfully completing the diploma program will have an entry level of technical understandingin how blasting is conducted. The students successfully completing the bachelor degree will havean in depth technical understanding of explosives and rock fragmentation. Having this uniqueand dynamic multi-level program provides the explosives industry with a pool of talent that canbe used to fill positions with graduates for all levels of the blasting industry."

Jan 1, 2016

By Mark S. Stagg, Stephen A. Rholl

The firing times of millisecond-delayed initiators are random variables that exhibit varying degrees of scatter. This scatter can cause crowding and overlap of adjacent delay periods, which results in adverse effects on safety, fragmentation, and blasting vibrations.

Jan 1, 1988

By Alejandro Rosario, Ricardo González

The restrictions imposed by the Brazilian environmental legislation regarding natural caves lead to a block of substantial amount of mineral reserves. Mining activities can released caves, as long as the company ensures that the activities will not cause any damage to them, requiring profound and time-consuming studies. Since the use of explosives in the mine are potential sources of some damage to any structures, it leads to a deep need for controlling the rock blasting activities. In this context, the maximum charge per delay used in operations close to cave regions must follow some internal blasting assumptions that have been developed during specific tests and mining activities. By the seed wave technique, it is possible to determine the behavior of a seismic wave, which travels through a rock mass and it is generated by blasting a known explosive charge. This technique has proved to be an effective tool because it is able to accurately include the physical characteristics of the rock and different lithologies. This paper discusses about modelling blasting induced vibrations in order to improve caves protection, which surround the mining operations.

Jan 1, 2019

By George Young Mosteller

This paper is summary of the practical solutions developed in the excavation of drilled piers (caissons) at GPCo's Plant Scherer, Juliette, GA. Plant Scherer is a 3,245 Megawatt Fossil Fuel Powerhouse and, when completed, will be one of the largest fossil fuel plants in the Southeast.

Jan 1, 1980

By Alday B. Andrews

A computer program called Seiswise that predicts the character and intensity of ground vibration generated by surface blasting operations was developed and field tested. The program uses the time histories of one or more pilot shots in combination with various initiation sequences to construct synthetic seismograms which are examined to select designs that will produce low levels of ground vibration.

Jan 1, 1990

By F. Malek

An extensive blast monitoring program has been carried out to study explosive performance and the effectiveness of blast designs in production blasts in a deep underground mine. Comprehensive monitoring of blasting vibrations through multi-station high-capacity high-frequency accelerometers, and borehole deformation history have been the main tools of such analysis. The mining activity involves relatively unstressed stopes as well as highly stressed stopes. More than 30 production blasts have been monitored, and the respective vibrations from close-range as well as distant seismic stations have been analyzed, and the vibration parameters (amplitude and frequency) have been correlated with explosive charge weight in the holes. It is found that the correlation between blasting rounds and the corresponding vibration amplitudes often have poor correlation for a very significant portion of the blasts. These point to either explosive charge malfunction in those specific blast holes, or inadequate blast design, or the effect of high in-situ stresses, or any combination thereof. This paper analyzes these variables and their effect on the overall blasting operation at the mine.

Jan 1, 2013

By Richard J. Mainiero, Harry C. Verakis, John J. Mulhern

There are application in coal mines where it would be advantageous from a safety stand point to fire unconfined shots. However, the firing of mud caps (adobes) or other unconfined explosive charges in underground coal mines is not permitted because of the explosion hazards associated with methane gas and coal dust. Present safety regulations in Title 30, Code of Federal Regulations prohibit such Practices. Recently, MSHA proposed revised coal mine regulations for the approval and use of sheathed explosives for Public comment.

Jan 1, 1987

By Yannick Bleuzen, Manuel Joao, Frederic Monath, Miguel Quaresma

The N1 Porto tunnel project is a 650m segment of large-scale civil engineering plan to improve traffic flow between Porto’s downtown district, the Santo Antonio hospital district and the highway access. The tunnel is being excavated into a massive “Granito do Porto” granite structure, 4 – 20m below a highly urbanized environment of Porto, Portugal. The project was originally started in 2000 and was stopped due to the inability to mechanically excavate the granite rock. The city of Porto engineers then turned to traditional drilling and blasting techniques. The use of pyrotechnical delay detonators did not easily comply with the specified environmental and safety requirements concerning blast charging, firing and vibration control resulting in the process taking far too much time. The introduction of digital blasting was proposed to overcome these concerns.

Jan 1, 2005

By V R. Sastry, D P. Singh, N R. Thote

Rock parameters which are uncontrollable impose restrictions on the procurement of desirable fragmentation. Blast design parameters which are controllable prove to be important tool in blasting operations. An attempt was made by the authors to investigate parameters which causes big oversize boulders in overburden blasting. A case study of coal mine is discussed in this paper.

Jan 1, 1995

By Ralph E. Burnham, J. Kelly Ratliff

"The words “dynamite,” “TNT,” “explosives,” and “blasting” typically cause the general public, andjurors, apprehension and fear. Although blasting operations conducted by well-trained, skilled, andexperienced blasters rarely cause damage or injury, the public’s perception of blasting is that it isdangerous, disruptive, and results in damage to nearby properties. As a result, blasting operations have always resulted in complaints, claims, and lawsuits. However, in recent years, the public perception combined with an increase in public opposition, social media, more stringent regulations, predatory plaintiffs’ attorneys, and the application of strict liability to blasting claims has resulted in an increased threat of litigation to blasting companies and individual blasters. Consequently, many blasting companies find themselves receiving more complaints, involved in more litigation, and facing an alarming number of frivolous claims, which can result in increased insurance costs and other financial tolls. Accordingly, today’s blasting companies must be prepared for litigation and take steps to eliminate accidents and claims before the first shot is detonated on a job. The best way to accomplish this is standard operating procedures that incorporate best management practices, industry standards, and regulations in daily operations. This paper outlines some of the considerations that a blasting company should incorporate into its standard operating procedures before, during, and after the shot."

Jan 1, 2016

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 Ron J. Elliott, Corry Coumans

The following is a detailed description of the blasting procedures used in the successful demolition of the Stave River bridge, Mission, British Columbia, Canada. This highway bridge spans a highly sensitive salmon-spawning river. Demolition of the bridge took place in a high liability situation in close proximity to sensitive structures. The new highway bridge carrying an exposed 150mm diameter gas line was located only 1.5 meters away. The bridge piers were blasted only seven meters from overhead power lines. Control of blast vibration, flyrock, and underwater overpressure was critical to the success of the operation. Electrical sequential blasting was used to ensure that blast vibration on the new bridge structure was kept below 50mm per second.

Jan 1, 1998

By Eduardo Lozano, Vilem Petr

This study demonstrates the ability of high-order, shock-capturing methods to simulate detonation wave propagation in right circular cylinders of non-ideal explosives. 2-D axisymmetric, reactive Euler equations were solved for the detonation of the highly non-ideal explosive ammonium nitrate-fuel oil (ANFO) using a simple pressure-dependent rate law and perfect gas equation of state. The fractional step method was applied to the convection and reaction operators using a 2nd-order Strang splitting. The flow solver consisted of a finite difference scheme where the flux is reconstructed by a modified fifth-order weighted essentially non-oscillatory (WENO5-Z) with local characteristic decomposition and local Lax-Friedrichs (LLF) flux splitting. Time integration was performed by a third order total variation diminishing (TVD) Runge-Kutta time discretization method, also known as the strong stability preserving (SSP) method

Jan 1, 2019

By Dworzak, Andrzej Biessikirski, Jozef Pyra

During the detonation process 20-30% of the energy is being consumed only on the quarrying pro-cess. The remaining amount of the energy generates harmful effects such as: shock wave, acoustic wave, fly rocks and ground vibrations. The ground vibrations effect is the most dangerous especially to structures which are situated nearby an open pit mine.

Jan 1, 2015

Previous approaches to pre-split blasting theory have tended to concentrate on the mathematics of dynamic stress wave interaction, whilst only recognizing some interaction with quasi-static stresses induced by expanding gases in the boreholes. However the decoupling used in pre-splitting is specifically designed to reduce dynamic effects to a level that a small degree of radial fracturing is created around the borehole which is emphasized and extended by quasi-static gas effects. It can thus be argued that the process has more in common with hydrofracture than with more conventional use of explosives.

Jan 1, 1984

By C. Kosloski, E. McCullough, A. Fox, S. Reed

This paper serves as a reference guide for creating or strengthening student chapters of the International Society of Explosives Engineers. This includes chapters that are just starting, currently undergoing transition in leadership, or that are in the process of rebuilding. ISEE student chapters have great potential to increase student involvement and national membership, and can benefit from formalized strategies to help them do so. Several key strategies are introduced and should be employed to promote organizational participation throughout the university system.

Jan 1, 2016

By Michael Louis, Charles Dowding

Concern over construction vibration-induced cracking has led to development of a new approach to vibration monitoring called autonomous crack measurement (ACM) and illustrated in Figure 1. This paper describes the concept as well as sensor performance in the first test house fitted an ACM system. Response of three cracks in this concrete masonry unit (CMU) house was measured as part of the system verification. ACM employs a single sensor that measures both weather-induced micrometer changes in crack width and those produced by habitation and ground motioninduced vibration. This comparison is displayed in real time via the Internet without human interaction. Graphic display through the Internet provides a new pathway for communication with the public. Such visual comparison of changes in crack width provides a simple alternative to the present system of comparison of measured and allowable vibration time histories. Measurements reported herein show that weatherinduced response of cracks is greater than that caused by presently allowable construction-induced vibration.

Jan 1, 2003

By Thomas Leonard, Philip R. Berger, Bryan E. Papillon

Bardon Trimount Inc., a large producer of aggregate, crushed stone, and concrete, was experiencing significant public opposition to its five quarries in the Boston area. It was believed by the authors that this opposition could be significantly lessened if the total number of blasts per week were reduced. Although the blasting company at these quarries, Austin Powder Company, contended that this could easily and safely be accomplished by increasing the size of the blasts, regulations precluded this alternative by limiting the total amount of explosives that could be used per blast.

Jan 1, 1996