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By William Reisz

Over the years as surface mining operations have become more sophisticated, angle drilling has become a more popular blast design technique, especially in areas where overburden and stripping ratios have increased. Another method of blast design is the staggered pattern, which greatly improves explosives distribution within the blast. While both methods present some engineering challenges, this paper will discuss how the two methods can be combined to enhance fragmentation, improve cast percentage, drill production ratios and highwall control. A practical engineering approach will be presented as well as a discussion on the discipline required to maintain a quality blasting plan.

Jan 1, 2002

By John Dean Smith

"In many operations the two most overlooked aspects in the drilling and blasting process is theblast optimization and explosive selection. Often times we find a blast design that seems to work andproduce acceptable results and will use this cut afier cut, even years. When in reality one should never become complacent and should be constantly looking for ways to improve the drilling and blasting operation."

Jan 1, 1995

By Jackson R. Pressley, M L. Hopkins, R E. Danell, N T. Moxon, Andrew Bowman

Efficient and cost effective blasting is achieved by closely matching the explosive energy to the strength of the material in which it is being used. Although there are many empirical relationships wich approximate this situation complete the blast optimization can only be achieved by quantitatively assessing explosive/rock interactions and explosive performance. The performance of an explosive is essentially governed by its velocity of detonation or the rate at which the detonation wave travels through the explosive column.

Jan 1, 1991

By Jason M. Ryan

"Along with recent advances in computer technology have come cost-effective systems desiiedto evaluate fragmentation distributions through digital images of particles. In mining operations andmineral processing plants, important data from these systems is obtained through monitoring sizedistributions at key stages of the comminution process. Blast engineers apply this technology as atool for the validation of empirical fragmentation models so that predicted results are more meaningful."

Jan 1, 1998

By Tom Treleaven, Andrew Williams

The town of Greenwich, CT, an exclusive suburb of New York City awarded several contracts for the installation of sanitary sewer in the North Mianus section of town. The Valley Road section was the most challenging from a rock excavation standpoint. The cut was up to 14 ft (4.25m), with adjacent utilities [20 in. (500mm) water, 6 in. (150mm) water and 8 in. (200mm) gas] located to within 5 ft. (1.5m) of the proposed sewer trench. Rock types varied but were ultra metamorphic in nature, ranging from quartzites, granite gneiss and various types of migmatities.

Jan 1, 2004

By Roberto Folchi, Hans Wallin

Having so many norms and technical content of legislation to deal with is a problem that an explo-sives engineer has to face, especially when working at an international level. Each country has its own norms and legislation, sometimes even each other region or state, as if the physics of explo-sions, rock, concrete, and masonry characteristics would change across the borders. Both norms and laws are frequently out of date, being mainly developed at the beginning of the previous century and adjusted, piece by piece, to a technical and political context that is constantly changing, with adjustment being frequently adopted in a hurry, due to a problem arising such as that of internation-al terrorism. Sometime also, norms are not harmonized with those they intend to amend, so required explanations and new adjustments lead to a vicious circle that increases confusion, complexity and depresses the explosive industry.

Jan 1, 2015

By Alex Chapman, Cam Thomas, Bryan Karney

"During the early summer of 1989, Ontario Hydro removed a concrete portion of the North Channel Dam at Crystal Falls Generating Station by blasting and excavating in marine conditions. Because of the severity of underwater blasting and because the site was in close proximity to the replacement dam, there was concern that hydraulic shock waves generated by the detonation could damage either the new dam or its control structures. This paper examines the data associated with the hydraulic shock waves generated by underwater blasting, and studies the effectiveness of an air curtain in reducing the peak pressures. In previous trials using the air curtain technique, a rule-of-thumb factor was used to estimate that only 10% of the original pressure pulse would propagate across the air curtain. However, this value had little basis in theory. A theoretical formulation of the problem by Karney in 1989 indicated a provisional value of 0.18 for this factor, but was heavily dependent on confirmation from in-field testing. Data provided by Ontario Hydro from an actual blasting procedure indicate that a more conservative value of 0.32 may be more appropriate. Thus.although the air curtain did provide considerable reduction of peak pressures, the data at Crystal Falls indicates its performance was below the anticipated level. However, due to problems with the instrumentation and some inconsistencies in the resulting data. it is recommended that this value be further refined as additional data become available."

Jan 1, 1992

By Alain Blanchier, Gilles Gomez

Neighborhood pressure on quarries has become urgent to deal with quarry managers and operators must apply the most recent technologies and communicate it for long shelf life time exploitation, the quarry in which the work is located in urban or suburban environments needs to take into account blasting rules as well as site environment. The main problems to be addressed are:

Jan 1, 2009

By Rob Farnfield, William Birch, Douglas A. Anderson

In the blasting industry, even to the most safety conscious shotfirer, misfires are a constant source of concern. In the United Kingdom, there are two types of misfire, as classified by the Health & Safety Executive. Type A occurs when testing a shot before firing reveals broken continuity that cannot be rectified. However, due to the fact that a majority of quarries use non-electric initiation [i.e. shock tube] that cannot be tested, this type of misfire is very unusual.

Jan 1, 2016

By Agne Rustan

The 9th International Symposium on Rock Fragmentation by Blasting was held in the Granada Conference Centre, Granada, Spain from the 14th - 17th September 2009. The Symposium was preceded by a 1 ½ day Workshop on “Vibrations from Blasting” organized by the initiator Dr. Alex Spathis and his colleague M. J. Noy, both employed at Orica Mining, Australia. Prof. Josè Sanchidrian at the “Universidad Politécnic de Madrid” in Madrid, Spain was the main organizer for both the Workshop and the Symposium. A record number of participants came (292) from a record number of countries (41). There were a total of 14 papers in the Vibrations from Blasting Seminar and 96 papers and 2 Keynote Addresses in the Fragblast 9 Symposium itself. The aim with this paper is to present some results from Fragblast 9 which are of interest for a large target group. One very important result from the Fragblast 9 meeting was that it was decided there that Fragblast 10 will be held in November 2012 New Delhi India.

Jan 1, 2009

By Nolan Eckroade, Nigel Pereira

Wireless electronic blasting systems are a new technology that enable truly wireless initiation through rock, air and water. This is achieved using low frequency magnetic induction waves to wirelessly send a firing command to groups of in-hole primers. Fully wireless initiation not only removes the limitations imposed by a wired connection to each primer in a blast, but also enables users to alter the paradigm of conventional mining techniques to advance operational productivity and reduce personnel exposure to high-risk activities. While initially deployed in underground applications, wireless electronic blasting is now being used in the open cut environment. To capture the early impacts in surface mining operations, case studies conducted at three surface mines evaluated blasts utilizing a wireless electronic blasting system against baseline blasts using conventional, wired initiation systems. The purpose of this paper is to outline the specific learnings associated with wireless electronic blasting in surface mining to date. The paper will include references to these specific case studies as well as benefits realized and applications for the future.

By Neil T. Davie, Thomas K. Blanchat, Thomas C. Togami, Joe R. Weatherby, Dale S. Preece, Robert A. Benham, James J. Calderone

"Geotechnical structures ,such as underground bunkers, tunnels, and building foundations aresubjected to stress fields produced by..the gravity load on the structure and/or any overlyingstrata. These stress fields may be.. reproduced on a scaled model of the structure byproportionally increasing the gravity field through the use of a centrifuge. This technology canthen be used to assess the vulnerability of various geotechnical structures to explosive loading.Applications of this technology include assessing the effectiveness of earth penetrating weapons,evaluating the vulnerability of various structures, counter-terrorism, and model validation. Thisdocument describes the development of expertise in scale model explosive testing ongeotechnical structures using Sandia’s large scale centrifuge facility. This study focused onburied structures such as hardened storage bunkers or tunnels. Data from this study was used toevaluate the predictive capabilities oft existing hydrocodes and structural dynamics codesdeveloped at Sandia National Laboratories (such as Pronto/SPH, Pronto/CTH, and ALEGRA)."

Jan 1, 1998

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 Roberto Folchi, Hans Wallin

Lake Mead, the largest man-made reservoir in the United States, is located about 30 miles southeast of Las Vegas, Nevada. For the construction of Lake Mead third water intake, which is entirely placed underground, an underwater excavation was needed at a depth of 100 m (330 ft): a large surface had to be deepened by 20 m (66 ft) in basalt.

Jan 1, 2012

By Alastair Grogan

In October of 2002, the author was retained by Public Works and Government Services Canada, on behalf of the Department of National Defense, to design, construct and test the effectiveness of a bubble curtain system at an underwater demolition range, near Victoria, BC. The purpose of the bubble curtain was to reduce the potential for fish mortalities at the site. This paper presents some of the elements of the design, along with the results of overpressure monitoring during blasting and compares the results of fish mortality and animal behaviors with and without the bubble curtain in operation.

Jan 1, 2005

By David Siskind

The authors studied small seismic exploration blasts for vibration characteristics and effects on structures in Mexico. Obtained were 267 three-component recordings of ground vibrations and structure responses from 62 test blasts at six single-story masonry structures. Charges were 4.55 kg (10 lb) of Vibrogel expolsive at depths of 20 and 30 meters. Initial blasts were 240 meters distant and proceeded towards the structures to as close as 5 meters. All blasts were in soil media in two basic types of terrain, low saturated areas and upland dry areas. Structural inspections were before, during, and after the test blasts.

Jan 1, 2002

By Sam Kangwa, Thomson Sinkala

Th e re are three basic types of hole deviations in long hole d ri l l i n g , n a m e l y collar i n g , alignment and tr a j e c t o r y dev i a t i o n s . In mining, the accur a cy in drilling has a significant effect on the effi c a c y and economy of mining oper a t i o n s . This ar t i cl e d e s c ribes the types, s o u r ces and effects of hole deviations in mining oper a t i o n s . The art i cle further demonstrates the economic consequences due to hole dev i a t i o n s .

Jan 1, 2004

By Yasunori Kosaka, Junya Tokita, Aramaki Shosaku, Inoue Junji

Light ANFO that satisfies blasters and customers who want to reduce the amount of explosive consumption without changing blasting effects and designs and passes Cap sensitivity test regulated by law. The reduced loading density of light ANFO reduces the amount of explosive consumption. The loading density of conventional ANFO is 0.X-0.9g/ml, while the loading density of light ANFO is 0.7-OXgiml. The detonation velocity of light ANFO is maintained not to reduce blasting effects. Detonation velocity of conventional and light ANFO using steel tube of inside diameter 36 mm are 3200 - 37OOms. detonation velocities are the same though the loading density of light ANFO is reduced by O.lg/ml. This suggests that the reactivity of light ANFO improves.

Jan 1, 2002

By David Flores, Benjamin Cebrian

Gold mining require high levels of dilution control due the high value of ore. These types of operations employ short benches, which are suitable for ore control, lower displacement and more representative block models. However, shorter benches makes fragmentation by blasting difficult because blast designs tend to be stiff in regards to burden/bench height ratio. This is especially relevant in hard, massive ore bodies where usual drilling diameters lead to poor energy distribution. In regards to control ore loss and dilution, there are different techniques to minimize both, which include: panel blasting, buffer blasting to muck piles and differential loading of areas of the blast bench. All of them should be sequenced with appropriate displacement along the ore/waste contacts. This paper describes extensive engineering approaches to achieve both dilution control while not hurting fragmentation in the very hard, massive ore sections of a mine case study. Ore Tracker microchips are used to correlate performance of these designs at the SAG mill (bottleneck of this specific operation). Another gold mine uses the same technology to detect when and where operational dilution is happening. The system tells where flagging of the different ore bodies has been followed in order to detect which operators pass the excavation limits beyond ore control flagging.

By Darren Thorton, David Sprott, Ian Brunton

Blasting causes movement of the rock and can be detrimental to the accurate delineation of the ore and waste regions within the resulting muck pile. The consequences can be ore loss and dilution. However, ore loss and dilution can be minimized and significant increases in profit can be realized if the movement can be accurately measured. Various methods have been used to measure muck pile movement including poly-pipe, chain and sandbags but these have been either inaccurate or impractical. The Julius Kruttschnitt Mineral Research Centre, JKMRC, has developed an electronic blast movement monitor that provides accurate three-dimensional movement vectors following a production blast. From this information, the ore block boundaries in the blasted bench can be adjusted to compensate for the measured movement and then ore recovery can be optimised. Following initial development of the prototype technology, the JKMRC further developed and demonstrated the system in actual production blasts at an open pit gold mine operated by Placer Dome Inc.

Jan 1, 2005