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The objective in controlled blasting is to reduce overbreak to control the final pit wall slope, shaft, drift ditch, bench, etc. to the final planned excavation limit. The six main types of controlled blasting utilized today are: 1) Line Drilling 2) Cushion Blasting 3 Smooth Wall Blasting 4) Buffer Blasting 5) Presplitting or Preshearing 6) Air Deck Presplitting

Jan 1, 1992

By Randall M. Wheeler

Many of us have used a seismograph to measure peak particle velocity and frequency. But do we really understand why? Also, why do we measure particle velocity instead of displacement and/or acceleration? What is the vector sum? How do these items relate? Where does frequency fit in? This workshop will attempt to answer these and other questions. Some of the answers may surprise you, others may not.

Jan 1, 1997

By V. Sastry

Signgareni Collieries Company Ltd. is operating the JK Opencast Project, at Yellandu, with a rated annual capacity of 1.6 Mt of coal with an average stripping ratio of 4.3. This opencast coal project has three working sections, OC-II block, C-Block and D-Block These workings are operating in close proximity to the JR-5 Longwall Shed, 26-Dip Incline, other structures of 26-Dip, and a Township. There were complaints about ground vibrations and fly rock problems caused due to blasting operations, especially in OC-II and D-Blocks. In view of this, studies were taken up to eliminate the problems of ground vibrations and fly rock.

Jan 1, 2001

By Lance McAnuff

The year 2001 coincided with the forty-fifth year of blasting-control specialization by the author. Commencing with the construction of the Saint Lawrence Seaway System in 1956 and continuing until the present time this career has spanned one of the most progressive and exciting periods in the still relatively short history of commercial blasting. The paper touches upon a number of the more interesting projects with which the writer was involved during those early days, including the removal by explosives of “Ripple Rock” the infamous underwater hazard to shipping which at one time inhibited ocean traffic along the Inside Passage between Vancouver Island and the mainland of British Columbia, Canada’s most westerly province. Various assignments involving incidents from devastatingly ,tragic to comically absurd are described, along with personalities encountered along the away, most of them readily recognizable as giants in the field of explosives engineering. Various stages in the evolution of state-of-the-art explosive products, initiation systems vibration monitoring equipment and limiting criteria are compared and some of the effects these have had on safety and productivity during the last forty-five years are analyzed.

Jan 1, 2002

By Ron Beeslaar, Tony Rorke

The Professional Blast Manager is a blast design tool that has been developed in South Africa. It is aimed at mining and civil engineen, blasting contractors and mine planning engineers. The code can be used as a stand-alone package or be combined Into complex mine information systems.

Jan 1, 1998

By Charles Deacon

The mining industry is constantly taking greater cognisance of their operating costs as a strategy to counter the effects of falling commodity prices. As a result, optimal operating efficiency is more important than ever. One such operation is that of blasting. Considering the relative increasing costs of explosives and accessories it is desirable to optimise the number of blast-holes fired by maximising their individual output. This achievement may now only be possible following the advent of higher technologies in the form of modified explosives and electronic detonators. This paper reviews and introduces some techniques of blast monitoring, types of operations where each is most suited, resulting modifications to blast designs, and identifies some pitfalls to watch out for when analysing the results.

Jan 1, 2000

By Janice K. Means

The purpose of this paper is to provide the seminar attendee with: information on pipeline construction, operation and standards to better equip him (or her) to analyze the ultimate effect of blasting stress on pipelines; an introduction to the analysis of blasting effects to pipelines using the American Gas Association analysis method; and; supplemental sources useful in the analysis of blasting effects to steel pipelines, and, in particular, on natural gas pipelines.

Jan 1, 1992

By Jaki Wilson, Les Armstrong, Neville T. Moxon

Low shock energy ANFO (ANFO) mixtures have been developed for use in fragmenting weak overburden materials and reducing damage.outside the blast zone in dry conditions. These mixtures can be readily produced on a minesite using conventional equipment and are formed by mixing low density additives such as polystyrene, bagasse and sawdust with ANFO.

Jan 1, 1990

By Charlie Adcock, Rob Farnfield, Andy Wetherelt

The ISEE Blasters Handbook gives guidance on the level of air overpressure likely to cause occasional window breakage (151dB) and general window breakage (171dB). A long-term safe level of 140dB is also suggested. This guidance is widely used by demolition and other contractors to assess damage zones in the region of explosive applications employing unconfined charges. Other reference material gives more detailed guidance relating to window area, aspect ratio and glass thickness. Despite the guidance given in these references, complaints by members of the public regarding window breakage continue to be received by explosives engineers from air overpressure levels well below the longterm safe limit. Such complaints are not limited to the use of unconfined charges but can even be generated from the highly confined use of explosives in quarry blasting. This paper describes a series of experiments with explosive charges fired in unconfined conditions close to various window configurations. The aim of the work was to test the existing guidance levels and to extend the knowledge base in this area. Topics covered include the role of differential pressure across windows in the walls of an enclosed space such as a room.

Jan 1, 2006

By Matt Slezak, Tristan Worsey, Nathan Rouse, Kyle Hall

As everyone knows, blasters are required to file blast reports of every blast for regulatory purposes. To this day, the authors see many handwritten blast reports. Handwritten blast reports are notorious for containing errors or omissions. This is not because the blaster intends to misreport information. It is because blasters have many tasks to complete in a day, are sometimes in a rush, and could accidentally miscalculate data, omit items, or record incorrect data. In most cases, blasters do not suffer consequences to these errors because blast reports are seldom reviewed in detail. In some cases, such as when a blasting operation undergoes some sort of litigation process, the reports are reviewed in detail and the blaster is ultimately held responsible. If the reports contain errors, the blaster can be fined, have his/her license revoked, or worse. Electronic blast reporting and centralized data management can help reduce or eliminate the potential for accidental blast reporting errors to occur. This paper presents many ways that electronic blast reporting can reduce or eliminate blast reporting errors, decrease time and extra costs spent reporting, and improve efficiencies in the field and the office.

Jan 1, 2018

By Gabsoo Kim, Rulin Yang, Dave Kay

Blast vibration data, such as PPV are usually scattered. In many cases, plots of PPV versus the charge weight scaled distance are so scattered that useful trends from different blast designs cannot be identified. The scattering of the data may be attributed to the inaccuracy of the PPV measurement, the definition of the scaled distance from a multiple-hole production blast, and the measurement of distances and charge weights. The error from vibration measurements is one of the major contributors to the scattering of the plots. If accurate monitoring is conducted, improved design options may be identified. This paper documents two case examples that compare different vibration sensor couplings. The first case shows mounting accelerometers at spots that protrude from the ground, compared with the sensors that were mounted on a flat ground surface. The second case compares data from loose-sand buried geophone with that from sensors coupled to the ground using concrete blocks.

Jan 1, 2014

By Ewan Selers, Gary Cavanough

Drilling automation technology is well advanced and automated drill rigs are in use at a number of operating mines. This is not the case for the other drill and blast processes due to significant technical challenges to overcome. These challenges, with regard to the current “on bench” practices, include placing the initiators, loading the explosive and connecting up the initiation system. Although difficult, these challenges will be solved with engineering advances.

Jan 1, 2016

By Bruce Vandenberg, R. Frank Chiappetta, John Foley

Recent advances in solid-state, field portable, fast framing compact video camera systems and PC based frame capture hardware now allow blast imaging up to 1000 frames per second. Up to 4.1 seconds of data can be captured directly into the unit, downloaded to a PC or archived to a standard VCR without data compression. Since no film processing is involved, motion analysis can be performed instantly and on-site within a few minutes. This paper will describe the design features and applications of the MotionMeter system and compare these with the analogous aspects of film-based cameras and other systems. Of all blast monitoring systems and techniques available today, high-speed motion picture photography and videography still remain as the most valuable, stand alone, diagnostic techniques for troubleshooting and evaluating full scale blasts in the mining and explosives industries. High-speed image data, coupled with information obtained from other instrumentation systems, such as continuous velocity of detonation recorders, laser surveying systems, refraction and ground vibration recording seismographs, etc., can eliminate many assumptions about what actually took place in a blast. Thus, diagnostic confidence in evaluating both excellent and poorly designed blasts is increased, and optimum blast results, (which are application dependent), are achieved considerably faster when compared to the trial and error approach of relying on strictly the experience factor. Applications include developing site-specific blast designs, decay equations relating burden, burden velocity and explosive energy, determining ground response times, reducing coal damage, quantifying backbreak, evaluating the effectiveness of sternming, checking delay detonator firing times, evaluating air decks and for studying general dynamics. Motion analysis is performed with a 2D and 3D software package developed specifically for video analysis, but is also directly applicable to film analysis when using a digitizer. Dimensional controls, lens aberration, field set-ups and camera orientation are all automatically corrected for with matrix analysis.

Jan 1, 2000

By David S. Bowling

The ER-300 Series White Recorders were developed to provide on economical, yet invaluable instrument for those who desire permanent recordings of such data OS displacement, vibration, concussion (air borne effect) and velocity information. The precise monitoring of earth displacements and air blast magnitudes aids quarrymen and construction contractors in estimating safe blasting limits when operating in populated areas. A refraction model is available for recording velocities which permit the determination of weathered zone depths as well as the .depths to other subsurface formations. The dual purpose (Refroction- Displacement) systems ore utilized for velocity studies and displacement - oir blast measurements.

Jan 1, 1990

By J. Mikhael Erekson, Connie Campbell Brashear, Brent Meins

Christmas morning 2020, an IED in an RV was detonated along an evacuated section of downtown Nashville, Tennessee. The blast damaged over 40 buildings, including AT&T’s Main Central Office and caused internet and cell outages across 1,200 zip codes for three days including the airport and EMS services. Published investigations by the ATF and FBI were inconclusive in determining the explosive composition and size. Video captured a large fireball that may indicate a fuel-air-mixture explosion which would create lower peak pressures than high explosives, but longer pressure duration and significant impulsive loading. Blast pressures were amplified by reflections in the urban environment bordered by the 8-story AT&T building and a row of multi-story historic buildings. Some structures had little damage as they were shielded from the blast pressure by closer buildings, and seemingly far-field structures contained damage from the pressure wave after multiple reflections and propagation through porous parking garages. Damage to the reinforced concrete frame AT&T building included snapped masonry ties, cracking and spall to the closest column, and vertical displacement of the elevator, even with the brakes applied. The historic structures directly across the street from the blast partially collapsed. Initial damage included complete failures of unreinforced masonry façades, broken timber beams, and uplifted roofs. Secondary, progressive collapse took place over months as the brick walls and weakened historic mortar could not resist typical wind and environment loads. One of the close historic structures was renovated in the 1990’s and structural retrofits to comply with building codes were required. The addition of steel columns and façade tie-ins improved survivability and it remained standing with a high percentage of the front brick intact. Generally, the observed blast damage was related to a structural component’s mass and flexibility. Internal timber framing was unscathed, but many steel studs required replacement. Glazing damage was observed several blocks away and many roof membranes were punctured by falling debris. Secondary damage from broken sprinkler lines and loss of environmental control often led to more costly repairs than the initial blast pressure damage. The proliferation of bomb-making knowledge leads to hundreds of bombings each year in the US. Building risk considerations should include explosive threats along with other hazards. ASCE structural standards and design manuals have been published to address these risks and may be useful guides for building construction.

Feb 6, 2023

By Tacio Ferreira

How state-of-the-art software, data analysis and communication applied to drilling and blasting techniques have have allowed quarries in the Midwest of the United States to improve results downstream

Feb 1, 2020

By A T. Spathis, M G. Wheatly

Some preliminary dynamic pressure data were obtained from several charges detonated in a tunnel situated in massive granite rock. The context of the work is the potential for desensitisation of explosives, failure of detonators, and sympathetic detonation due to the close proximity of inter-hole and inter-deck explosive charges to each other. Dynamic pressures were measured using piezoelectric gauges in water-filled 45 mm diameter holes adjacent to the charges. Some of the first arrival peak pressures were noisy, and although not fully resolved, may be due to reflections and the physical arrangement of the transducers and their size with respect to the monitoring holes. The estimated peak pressures were between 0.1 to 8.7 MPa at approximate distances of 2.8 to 0.8 m, respectively. Further work is planned with gauges that are disposable, have a higher pressure range, and can be used within a few borehole diameters rather than the piezoelectric gauges used in the present work.

Jan 1, 2016

By Tom Palangio, Ralph M. Olmstead

Video inspection of boreholes with cameras developed specifically for the mining industry is now possible. These designs are reliable, cost effective, and have the flexibility to be used in other applications.

Jan 1, 1998

By Cathy Aimone-Martin, Brent Meins

A comprehensive instrumentation program was implemented at the Howland Hook Marine Terminal on Staten Island, NY during proximate underwater rock blasting in 2014. Forty-two blasts took place over a 4-week period to deepen the 1200-ft (366 m) Berth 3 from -45 ft (-14 m) to -50 ft (-15 m) MLW to accommodate Post-Panamax vessels. Approximately 86,000 yd3 (65,752 m3) were blasted 120 to 9 ft (37 to 2.7 m) from the wharf to a total depth of -57 ft (-17.4 m). Pre-blast planning included developing and implementing a comprehensive monitoring plan and setting vibration and strain limits to protect the wharf. The plan outlined methods to measure vibrations on five corners of four concrete deck sections, on five concrete-filled pipe piles just below the pile cap near deck corners, and in bedrock adjacent to pile sockets. Water overpressures were measured near instrumented piles for 19 blasts closest to the wharf. A total of 19 geophones were secured to the wharf structure and buried 12 ft (3.7 m) in drilled holes.

Jan 1, 2016

By Gordon Revey

The challenge of managing blasting risk, types of risk, public perception, and a system for managing risk were covered in the first part of this article in the May/June 2000 issue of the Journal of Explosives Engineering. This final part of this two-part series provides a method for identifying specific blasting risks and reviews the importance of community relations.

Jan 1, 2001