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By B Mohanty, R Yang

Blasting vibration information is now commonly used to diagnose blast malfunctions. These range from limiting vibration levels to protect normal dwellings to determining scatter in detonator firing times, and even to rating of explosives in the borehole. Although blasting vibrations have the potential to yield reliable information in all these issues, there are key restrictions on their specific use, which are often ignored. These include all aspects of instrumentation, and sensor layout, as well as methods of analysis. This paper highlights these limitations. It emphasizes the distinction between near-field and far-field seismic recording in terms of borehole dimensions and blast geometry. Several case studies from both underground and open-pit blasting operations are discussed to illustrate and emphasize the essential characteristics of blasting vibrations and their optimal use in diagnosing blast malfunctions.

Jan 1, 1997

By Robin L. Simmons

Mining in the Genesis open pit has been conducted above the active haulage and ventilation declines of the Deep Star underground mine. Production has continued in both mines. The Deep Star haulage and ventilation declines, the primary and secondary egresses respectively, had to remain open and safe for travel until the new haulage and ventilation accesses were completed. Eventually, the upper 350 feet in each decline will be removed. The declines are in relatively competent calc-silicate hornfels with several high-angle, northeast-striking, clay-filled or open-spaced fault zones that create localized areas of poor ground requiring steel sets. To maintain the integrity of the declines, blast-induced vibration levels and damage were monitored in both declines after each surface blast. Seven geophones were installed in the declines to monitor peak particle velocity and peak vibration frequency. These data helped design subsequent blasts and predict expected vibration and damage levels. Blast design modifications included reducing the pattern size, reducing the powder factor and limiting blasthole detonations per delay. While limiting blast-induced vibration, these blast design modifications had to allow effective surface mining to continue. Linear regression analysis of peak particle velocity and scaled distance was used to determine the scaled distance necessary to keep the peak particle velocity under 2 inches per second. To date, the new ventilation raise, which is also the secondary escapeway, has been established and safe conditions were maintained in the original ventilation decline. Data collection and conscientious blasting procedures continue above the haulage decline.

Jan 1, 1998

By Laurence Neufville

Proper risk assessment and blast design are very desirable to the execution of a blast. Not only will this ensure that it achieves its desired outcome, but the probability of complaints and litigation will be reduced. Blasting engineers rely heavily on site-specific data for analysis and input to the blast design equations, and therefore data collection is critical to this process. The traditional approach to data collection is to carry out site-specific reconnaissance by visiting the site, but the time spent doing so can be reduced if a remote sensing approached is adopted.

Jan 1, 2009

By Leslie Taylor, R. Reed Skagga, William Gault

The ultimate aim of our overall task, of which the effort described in this paper is a part, is to be able to model the impulsive output of buried charges and the response of targets of interest. It is not practical or cost-effective to determine the response of all targets of interest to buried charges of all sizes by testing them. In order to have confidence in our models, however, they must be validated by a modest number of tests. A critical element in modeling the response of a target is the ability to model the loading function. The load a buried charge applies to a target above it when the charge detonates can be characterized in terms of the vertical impulse. The vertical impulse is a function of the size of the charge, its depth of burial, and the properties of the soil in which it is buried. The primary objective of the effort described in this paper is to determine the load a known charge places on a non-responding target so the data can be used to validate our models.

Jan 1, 2005

By Alejandro Berrios, Matheus DaSilva, Erick Siqueira

Vazante mine is an underground polymetallic mine that produces zinc, lead, and silver, which belongs to Nexa Resources in Minas Gerais, Brazil. The mine, a sublevel stope underground mine, mainly applies two subvariants: VRM – Vertical Retreat Mining and Open Stope. In a specific place of the mine, the geology allowed the design of a production stope with larger dimensions than the standard stopes, commonly called Super Stope. At this place, the plan was to apply both sublevel variants simultaneously. This mining block comprises rings in two different levels, with access by two ore drives on each level; the dimensions would be approximately 50 meters high, 50 meters long, and 35 meters wide. Opening the Free Face to mine the whole Stope was a challenge due to operational issues, such as hazard risks from loading over void space, exposure to uncontained places, and the impossibility of implementing the optimal blast sequence. Wireless blasting initiators have gained popularity recently due to their convenience, safety, and efficiency. This initiation system was applied to preload all the rings required to open the Free Face, ensuring a safe and optimal blast sequence. Wireless initiation prevented hazard risks, enhanced the blast sequence to guarantee the required void space, and optimized the equipment's operational cycle. The blast crew carried out the activity without exposure to the risk of loading over void space. The wireless detonators also avoided after-blast activities, which were required to provide secure access to the blast crew, optimizing the operational cycle.

Jan 21, 2025

By Everett Clausen, Richard Walker

CIL/EVANinc and the Canadian Explosives Research Laboratory of the Government of Canada have evolved a concept developed by Research Energy of Ohio, into a landmine neutralization system that is the most innovative to date.

Jan 1, 1999

By Steve Collinsworth

Sometimes, for those of us in the right place at the right time with the right product, necessity creates opportunity. Such is my case at a West Virginia coal mine where a mine manager was desperately seeking a way to eliminate coal damage on cast shots while maintaining cast percentage without the expensive process of secondary drilling. This paper will focus on how bottom hole air decking is solving the problem.

Jan 1, 2000

By Franklin J. A, Tam C. Palangio, N H. Maerz

WipFrag systems I, II and III have become the world standard in photoanalysis systems to measure particle sizes. Mines, quarries and excavating contractors can now easily measure blast results and track the progress of optimization efforts. This technology was developed and evolved ~to allow automatic measurements of the size distribution of particles on moving conveyors, in truck boxesand on crusher feeds. Production machinery can now be controlled by photoanalysis results and multiple cameras allow various locations to be monitored by a single system. Blast designs can, be monitored on a shot by shot basis. Changes in delay times, explosives, patterns and hole sizes can be quickly evaluated. Along with this measurement capability has come a heightened awareness of the importance of “optimum size” and uniformity of particles for lowest cost production and material handling efficiency. In the past, savings in the “drill / blast” cycle of the operation were sometimes overshadowed by downstream production costs related to fragmentation. Now total production costs can be compared with fragmentation sizes, which will immediately show the trend towards optimum size for economical production. No cost reduction program can be complete without this critical information.

Jan 1, 1998

By Stephen John Brace

Increasingly, electronic blast initiation systems are being made available to the mining and construction community, both in South Africa and internationally. Indeed, in some parts of the world, perhaps half a dozen electronic products are being used, with a choice also of shock tube, electric and fuse and igniter cord systems. As these developments have taken place, improvements have been made in safety, reliability and accuracy, so much so that high performances in all these areas are now expected. However, disadvantages often seen by customers, other than : higher price, are decreased user-friendliness and loss of flexibility.

Jan 1, 1998

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 Yves Lizotte, Malcom Scoble, Sanu Hanspal

"This paper reviews the physical, chemical and mechanical components of what is considered to be the anatomy of a blast muckpile. These relate principally to geometry, floor, fragment size and shapedistribution, density, hydrology, weathering, and diggabiity characteristics."

Jan 1, 1995

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 W. Reisz

The fear of heights is a natural defense against performing a dangerous and unnatural act such as standing on the edge of a hundred foot wall. Yet through familiarity, a casual attitude often exists. Those of us, who work near highwalls on a daily basis, may become overly comfortable in our surroundings, losing sight of the disaster which may often rest a single misstep away. And this is where the hidden dangers lie.

Jan 1, 2009

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 David Hersey

The Paseo Bridge was located at the I-29/I-35/US-71 Missouri River Highway Crossing. It was built between 1952 and 1954 by Massman Construction Company. The 1,232 foot long, self-anchored suspension bridge was the longest of its type when built. On Jan. 22, 2003, a connector pin designed to allow the bridge to expand and contract during temperature cycles seized and caused a portion of the bridge deck to raise up and block traffic. This marked the beginning of the end for the old Paseo Bridge.

Jan 1, 2013

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 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 Charles E. Joachim

Railroad and blast induced vibrations were measured in the vicinity of the proposed Big Bend Cutoff. Peak horizontal and vertical particle velocity relations were developed using least squares regression analysis. The dominant frequencies of these data are in the range of 30 to 50 hz. Therefore, allowable charge weight per 30 msec delay curves were generated for buildings (2 in./sec) and unlined tunnels (8 in./sec). A blasting contour map is presented for this site.

Jan 1, 1984

By Andrew F. McKown

Overbreak and damage to rock walls at the perimeter of rock excavation can lead to safety problems due to rock falls and additional costs due to a] extra mucking, b] extra concrete or shotcrete to backfill overbreak, c] additional rock reinforcement, d] additional water inflow and e] additional maintenance of rock walls. To minimize these undesirable effects, there are several perimeter control techniques available (i.e. line drilling, cushion blasting, pre-splitting, smooth blasting, and fracture control blasting) which control perimeter hole spacing, burden and loading to provide a smooth, stable excavation contour. Conventional perimeter control loading and hole spacing is satisfactory for massive, homogeneous formations, but when blasting in weathered or fractured rock closer spacing and very light loading is required.

Jan 1, 1984

By Alastair Torrance, Italo Onederra, Do Sun Kim, Kush Patel, Gary Cavanough

Reactivity of ammonium nitrate-based explosives is associated with the presence of sulphide in the ground reacting with explosive products and in some instances causing spontaneous reactions which can lead to detonation. This paper explains the mechanism of these reactions, the potential cause of spontaneous detonation and how inhibited explosives prevent the reaction

Jan 1, 2019