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By Kurt Oakes, Paul Worsey, Braden Lusk, Tony Brasier, Scott Crabtree, Randy Wheeler

Theoretical description of destructive wave interference and the use of sacrifi cial holes is included and is supported by data collected at Springfi eld Underground. Finally, the process by which the reduction in vibration was achieved in practice is described. Results are discussed for several production blasts taking place over a one year period.

Jan 1, 2008

By Daniel P. Lathrop, Leslie C. Taylor, William L. Fourney

Except when the target is on the surface, e.g. a tank track, the most important loading mechanism from a buried charge on a target above it is the impact of soil propelled at the target by the expanding gas from the explosion. Detonation of a shallow buried explosive generally yields an unstable interface between the rising soil and the air which appears to be the result of Richtmyer-Meshkov instability. Irregular “fingers” of saturated sand extend into the air above a more generalized dome of soil. These fingers move at a much higher velocity than the material between them at smaller stand off distances. As a result, the local load on the target at positions on the target at the same distance from the charge may vary by 50% or more from shot to shot or even within a single shot. This variation requires a large design safety factor to assure the integrity of design of mine-resistant vehicles.

Jan 1, 2009

A simple and cost effective technique to increase fragmentation and burden velocities without making major modification to the overall blast design is with ALTERNATE VELOCITY LOADING OR BOOSTERING OF ANFO. The technique requires the placement of a cartridge or slug of explosive, having higher density and detonation velocity than ANFO, every few feet in an ANFO column. The greater the difference in density and detonation velocity of the Alternate Velocity Load to ANFO, the more pronounced are the results. Emulsions were selected as the Alternate Velocity test explosives because they detonate closer to ideal conditions than most other commercial explosives.

Jan 1, 1989

By Jason M. Ryan, T Michael LeBlanc, John H. Heiiig

Drill trajectory deviation is a recurring problem in the Mining Industry retreat stoping operations. As a result of this deviation, it is quite concevable that 60 kg (165 mm 0) and 103 kg (203 mm 0) explosive charges are detonated beyond the hanging wall contact. Consequently, there follows a reduction in hanging wall stability and an increase in ore dilution.

Jan 1, 1995

By Frank Sames, Brad Terhune

In many construction projects and in most quarrying operations drilling and blasting remains the only feasible method of loosening rock in the removal of rock or overburden, the development of the quarry and in the production process of crushed stone. Often, a blasting plan is required for the project or the quarry’s permit with primary concerns over safety and site security, and compliance with environmental regulations or standards. From this plan, a blasting program has to be developed considering the varying requirements of production, the advance of the mineral extraction and the environmental impact. The actual blast design requires a planning and optimization process. This optimization process is driven by the blasting technicians/engineers, project or mine management and often by community concerns. The blast design process comprises the selection of blast parameters, including the explosives, and the actual layout of the blast. Design tools and controls range from conventional methods based on established blasting practices to advanced design tools or computer models. Blast monitoring and evaluation can also range from empirical to advanced blast assessment. The data and information from each blast or a series of blasts can further be used in the optimization process. Its success depends upon recording the data, the timely transformation of the data to relevant information, and the development of process oriented knowledge. The elements of the blast design process are summarized and described with examples of state-of-the art engineering controls. The reporting and monitoring of individual blasts is discussed with respect to data management and information systems. A conceptual overview of the components and interfaces of a blasting program is given and discussed on the background of technical, management and community concerns.

Jan 1, 2004

By Laurance A. Beck

Safety is the most important aspect of haul road design. Although other aspects of road installation enter decisions on design, the safety of persons using the road has to be foremost for the duration of haul road usage. Other aspects of mad design focus on minimizing truck cycle time and fitting haul roads to the long-term configuration of the mine/quarry or construction project. Roads are often installed at high gradients for a short-term goal, but the long-term benefits are easily shown with lower gradient haul roads which provide better cycle times and lower operating costs.

Jan 1, 1995

By Seokbin Lim

In the design of explosives devices, an understanding of the behavior of explosively propelled matter is one of the most important steps in maximize the performance of these devices. For instance, an explosively driven metallic liner in LSCs (Linear Shaped Charges) creates its functional effect of penetration after a finite distance of travel (before collapse), thus the detailed study of the projection mechanism of the flat liner after detonation helps in the optimization of the design of LSCs. In a typical metallic flyer driven by explosive detonation, the detonation gas propels nearby matter including flat flyers. After a certain degree of expansion in the detonation gas, the flat flyer reaches its maximum velocity and slows down afterward. These typical behaviors are well investigated and numerically studied by many researchers. However, the rarefaction intrusion (detonation gas expansion) near the surface of the explosive charge creates significant deformation of the flat flyer , and produces U-shaped bending or deformation near the edge of the flyer during projection, creating unexpected behavior in explosive devices of interest. In this paper, a preliminary investigation of a localized Ushaped deformation of flat metallic flyers during projection is studied utilizing a theoretical approach and computational modeling facilitating an understanding of a general tendency of the deformation behavior.

Jan 1, 2010

By Rapheal Trousselle

For over 5 years, Davey Bickford has been developing and testing an electronic detonator blasting system. These new-technology detonators provide more accurate timing than conventional systems that rely on the combustion speed of a pyrotechnic composition.

Jan 1, 1997

By D Frantzos, J J. Cotter, H Tammemagi, J B. Codrington, J Kaasalainen, A C. Webster

"Exploshres Technologies International (ED) is developing an instrument called ROCSCAN which isplanned to have broad application in both blasting and rock mechanics. The purpose of this paper is to outllne the background that has led to the development of ROCSCAN, describe its objectives and to present a progress report on the work to date. Some of the potential applications of ROCSCAN will also be reviewed."

Jan 1, 1989

By L C. Taylor, H U. Lesiste

This is a preliminary study of the statistical variation of the pressures on a target above a buried explosion. The data were taken at various distances from the charge centerline for three heights of the target above the soil and one charge depth of burial. All tests were conducted in saturated sand. They show that peak pressures and times of peaks are neither repeatable from shot to shot nor rotationally symmetric within a single shot. The peak pressure and time of peak at each location can be represented by cumulative normal distributions. The paper describes the means and standard deviations of these distributions at eight distances from the charge center for each height of target. These are used to determine the change in standard deviation of the distribution with distance from the charge centerline and height of target. The effect of scale on the mean peak pressures and times of peaks and on their standard deviations at a single scaled distance from the centerline of the charge are explored using various charge weights.

Jan 1, 2010

By Randy Wheeler

One of the more difficult topics to address concerns the effects of vibration on historic structures. Not only blast induced vibration, but also vibration from other transient and semi-continuous sources like, traffic, human activity, and environment forces. A common question might be, “What level of blast-re l a ted PPV is considered safe?” A review of some of the papers available from the ISEE Explosives Reference Database on CD ROM shows that 0.50 inch per second was often used. It was not clear on what basis this value was selected except that it represents the low frequency limit for plaster developed by the United States Bureau of Mines in RI 8507. In another case, a limit of 0.20 inch per second was mentioned, apparently simply because it was ten times less than 2.00 inches per second.

Jan 1, 2004

By Alastair C. Torrance

"A brief review of the Australian mining industry is given followed by a more detailed treatment of a study of the influence of primer Size on explosive performance. This is based on a joint research programme conducted by BHP Central Research Laboratories and Dyno Wesfarmers Ltd and examined the effect of the size of cast primers on the run up and steady state detonation velocitiesof ammonium nitrate based explosives as a function of blasthole diameter. The field trials examined a numter of the Dynamo 'Westfarmers HDF series of primers in conjunction with ANFO, emulsion and watergel explosives. Results indicate that the iun up velocity of 187 mm diameter ANFO charges is negligible using cast primers as small as 150g. However, emulsion and watergel explosives did exhibit run up in both 187 and 3:1mm diameter blastholes, independent of the size of primer. This could last from 7 to 10 blashole diameters"

Jan 1, 1991

By Joshua Taylor Drake

This report answers specific questions concerning underwater blasting considerations, and blasting safety. The blasting considerations discussed consist of basic blasting principles, and new variables to be accounted for. Blasting safety will include the safety of personnel and structures. The environmental considerations will also be discussed with mitigation methods. To be most effective, this document requires the reader to be familiar with key fundamentals of explosive engineering. In order for a blasting professional to benefit from this report, the following questions will be asked:

Jan 1, 2015

By Dominic Orf, Gregory Poole

On December 12, 2018 at 4:14 AM EST, an earthquake registering a 4.4 magnitude on the Richter Scale occurred in central Tennessee. According to a survey posted on the USGS website, this earthquake was felt throughout the southeast and even as far away as Arnold Nebraska. That’s over 900 miles (1,448 kilometers) from the epicenter. We recorded the vibrations from this earthquake on 44 different seismographs that were set up with remote access to continuously monitor vibrations from blasting activities. Having this data gave us an opportunity to compare the vibrations caused by earthquakes and blasting. A simple observation of the amplitudes, frequencies, and durations is enough to notice that vibrations from earthquakes are very different than vibrations caused by blasting in mining and construction. We were also able to observe the dissipation of the vibrations from the earthquake and see if the low frequencies, that are typical of earthquakes, dissipate at a consistent rate. Regression calculations were performed in order to see if there was a good data fit and if a specific vibration prediction could be made based on the magnitude of an earthquake. “How does quarry/mining/construction blasting compare to the Richter Scale?” This is a very common question that we get from homeowners when discussing vibrations due to blasting activities. This paper is intended to provide some simple answers for such a complicated question. Both the Richter and Mercalli scales are compared to the particle velocities as they were recorded from this earthquake.

By C. M. Badeen, J. Paige, W. Evans, L. McCauley, A. Caddies, I. Alilovic, R. Turcotte, C. O. Lyogun, C. Bonner

Gear pumps are very commonly used for the pumping of AN-water based emulsion products for both handling and blast loading applications. The potential major hazardous problems likely to be encountered with these pumps are: (i) high probability of friction; (ii) possibility of product confinement in the area of the bushings; (iii); high bearing failure rate; (iv) pump running dry; (v) presence of foreign material; (vi) deadheading of pump; (vii) delamination of elastomer from steel gears. Of all these possible scenarios, the no-flow situations where the pump is running dry or deadheaded have always been recognized as the most serious ones.

Jan 1, 2015

By Chris Breeds, Larry Leone, Jerry Wallace

Project Owners typically require General and Detailed Blast Plans when blasting close to important structures and specify the maximum allowable peak particle velocity for each potentially affected structure. Low, residential level PPV limits may be specified which significantly restricts the potential for blasting to be effectively used. Contractor’s responding to these contract conditions typically cite historic case studies which may, or may not, apply to the specific situation and/or types of structures for which limits have been set. A long submittal cycle typically follows.

Jan 1, 2010

By David G. Borg, John Bussey

The new AIRDEK (tm) technique for pre-splitting in surface coal mines produces highwall conditions that have greater safety with lower costs for explosives, labor, and drilling. Successful applications have been made in highwalls ranging from 20 to 100 feet or more and in blasthole diameters from 3-1/2 inches to 12 inches.

Jan 1, 1988

By Scott Rosenthal, Logan Connolly

Butte, Montana holds a prestigious place in the history of mining, deemed “The Richest Hill on Earth,” containing a plethora of underground mines. The Orphan Boy/Orphan Girl underground mines, on the western side of Butte, operated from 1895-1956 producing zinc, lead, silver, and manganese. Today, the Orphan Boy mine is part of Montana Tech’s Underground Mine Education Center (UMEC) and the Orphan Girl mine houses the World Museum of Mining. Underground development in the Orphan Boy mine continues to progress as students from Montana Tech receive hands-on underground training; in addition, the UMEC is a multi-disciplinary research facility. Repeated underground blasting occurs in close proximity to old mine workings (wood supports installed circa 1950 or earlier). Research began to determine the impact of underground blasts on nearby pre-existing structures. Using the ISEE Field Practice Guidelines for Blasting Seismographs, one seismograph monitors the predominately-wooden structures to measure their response during each underground blast and one seismograph positioned on the surface to monitor surface structure response to the blast. This paper presents the findings of the research conducted to date for the project. The paper includes analysis of the research data, and conclusions determined from the research. Recommendations for the future work are included as well.

Jan 1, 2018

By Kristen Dunlap

There are several thousand remote stream crossing structures in the Tongass National Forest in need of removal. In 2007 thirty-three collapsing log bridges, log culverts, and metal culverts no longer in use were removed with explosives. Species of salmon, trout, char, and sculpin are present in the project area. Blasting overpressures may injure or kill fish in streams and ground vibrations can damage salmonid embryos in streambeds. Regulatory agencies offer guidelines with limits for blasting induced overpressures and vibrations. However, there has been no quantification of blast overpressures in shallow streams. Methods used to predict lethal levels for various blasting applications have not been completely validated. This research provides guidance for analyzing ground vibrations and water overpressures during blasting activities in or around fish streams.

Jan 1, 2009

By David G. Borg

"Although researchers have realized varying degrees of success in numerics modeling, computer blast simulations and small scale in-situ testing, most will agree that the greatest uncertainty in total success stems from the uncontrollable field variables. Given the diverse nature of field conditiorencountered, no reliable and proven method of evaluating fragmentation quantitatively, and the lack of adequate field controls found in many operations, it is unlikely that a universal plug-in model will be developed for all blasting in the imediate future. This does not imply that all research devoted to modeling should cease, for it is precisely here where more research efforts are desperately needed."

Jan 1, 1989