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By Mario Karfakis, G. Langlois

Well stimulation is the process by which any production well, whether for production (extraction), storage (injection) or deep interaction (remediation, monitoring, etc) can be made or stimulated to flow at higher levels. This stimulation is driven by active methods to increase the permeability in the near-well environment and create a larger zone of communication between a well and the reservoir it services. Well stimulation is a crucial aspect of well completion and reservoir engineering and is a subject of careful pre-drilling planning. In many modern industrial endeavors the effectiveness of well stimulation is often critical to economic viability. Because of the broad impact of well engineering on several large industries (petroleum and natural gas extraction and storage, geothermal power, groundwater monitoring, extraction and management, environmental remediation, mining and minerals extraction, etc.) changes in the state of the art in well engineering and well stimulation can affect the capabilities of very diverse and disparate industries. This paper is an effort to communicate the status and effectiveness of current practice and technology in well stimulation. The intention being that effective communication of progress can spur innovation in industries that require well stimulation but are removed from immediate communication of technological or practical improvement.

Jan 1, 2009

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

By B Mohanty

Full-face blasting rounds have been used to excavate a 4.6-mdiameter shaft at Atomic Energy of Canada Limited's Underground Research Laboratory near Pinawa, Manitoba. Both standard pyrotechnic delay detonators and the newly developed electronic delay detonators (EDD) were used on the project. The full-face blasting technique, employing 89-mm-diameter relief holes and 38-mm diameter blast holes, NG-based explosives, and the regular long period delay detonators, has been standard practice at the site, giving excellent wall control and fragmentation results. The comparison blasts using pyrotechnic detonators and EDDs were carried out to test the operational logistics, timing accuracy and blast results obtained with the latter. The long period pyrotechnic delays ranged from O to 18, with the nominal delay varying between 350 ms and 800 ms. The EDD blasts used the same number of periods, with the respective delay interval between successive periods set precisely at 190 ms and 210 ms for the two blasts. Based on a broad range of critically assessed parameters, the EDD blast results proved to be signficantly superior to those obtained with regular pyrotechnic detonators. The results have been analyzed in detail and the relative merits of the two delay systems have been determined. Alternative designs to derive maximum benefits from EDDs in shaft and tunnel blasts have also been suggested.

Jan 1, 1990

By Greg Mclellan, Mark Johnson, John Pepper

Several large quarrying projects recently occurred in Miramar, Florida. These were closely monitored by the Seismologist of Record and Broward County in accordance with County and City regulations. In addition to this monitoring, the City of Miramar employed The Pepper Engineering Group, Inc., to provide additional spot check monitoring and to review the records of the other two parties on a routine basis. Broward County ordinances require that the location of each shot and the nearest protected structure be recorded along with seismograph measurement of each shot at the nearest protected structure. The positions of the blasts and nearest protected structures were determined using GPS. The blast vibrations were measured by seismograph. Over 600 shots, which are the subject of this study, were measured both by the County, the Seismologist and, on many occasions, The Pepper Engineering Group. As such, the vibration data was constantly cross-checked for consistency. The blasting contractor also provided blast designs for each shot. In this paper, the measured vibrations are plotted in terms of Resultant Peak Particle Velocity (RPPV) versus Scaled Distance (SD) on logarithmic scales. The data curves are fitted with least squares and upper 95% and 99% prediction limits are provided. Equations are presented to predict the RPPV based on scaled distance and prediction level using power fits. Statistical information concerning the derivation of the various limits is presented. The raw data used to develop this paper, along with other information concerning the shots, will be posted on the Internet for use by other researchers.

Jan 1, 2000

By Paul Sairato, Cathrine E. Johnson

Recruiting and retaining students in the explosives industry is becoming increasingly important each year. With no undergraduate degree in explosives engineering currently available in the United States, it is from other industries and degree disciplines we must recruit. The 2014 annual ISEE conference saw the first anonymous online survey distributed to members of SEE student chapters of the International Society of Explosives Engineers. The survey contained questions about future job and career plans, ideal job placement, expectations of salary and current academic degrees. The purpose of the survey was to determine what these students expect or require from a career in the explosives industry, and their current path to pursue this. This information can help steer recruitment activities and job offers for graduating students. The success for both student response rates and interest from the industry has allowed space for a yearly update of this survey. This paper provides the data from a second, restructured, online survey distributed to all student members of the International Society of Explosives Engineers, globally. Understanding the main incentives for a student to accept a graduate position as an explosives engineer can help us, as an industry; position ourselves to remain competitive in recruiting against other major degree disciplines.

Jan 1, 2015

By Joshua Micah Hoffman, Catherine E. Johnson

The recruitment and retention of future talent into the explosives industry is becoming increasingly important. One potential area from which future talent can be recruited is local student chapters. Many of the student chapters are closely connected with engineering programs. While this makes sense and both entities benefit from these arrangements, there is a trend of job placement primarily in the engineering industry. Before the explosives industry can begin to compete with other industries, it should be determined what is drawing the students into these other fields. The work presented in this paper sought to better understand the collegiate student population from which a portion of future explosives professionals will emerge. This was done through the use of an anonymous online survey distributed to the student members of the International Society of Explosives Engineers, as well as, members of SEE student chapters. The survey contained questions about future job and career plans, ideal job placement, and expectations of salary. The purpose of the survey was to determine what these students expect or require from a career in the explosives industry. This information can help steer recruitment activities and job offers. Through understanding what is incentivizing these students who have accepted or plan to accept jobs in other industries the explosives industry can better posture itself to be more competitive in recruiting from the collegiate talent pool.

Jan 1, 2014

By Corry Goumans, Dan Agostino

Photo 1. Demolition work on the Pitt River Bridge. The drill crew is using the 3800 Gardner Denver Air Track to drill the holes on the Bridge turning dolphin. The barge in the background is used for support.

Jan 1, 2013

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 Robert C. Brown

During a research period lasting over three years, a vast number of seismograms were collected and analyzed. From this data, other than obtaining a host of new information pertaining to the effects of surface mine blast on underground mines, it was found that by mounting seismograph velocity transducers at the center of crosscuts in underground mines, seismograms can be obtained which give fairly accurate information about the maximum levels of vibration, and the associated Of stresses and strains, misfiring of blast holes, delay accuracy and delay overlap. The technique of analysis is a simple one; it involves matching of the frequency of wave or wave groups with the shot card information such as rows of holes, number of holes and the cumulative milliseconds of delays used in the blast holes. Any discrepancy that might exist between the frequency of waves and the expected cumulative millisecond delay for a given row or hole eventually will show up as a mismatch in the analysis. This simple technique enables the seismographer to be involved not only in the monitoring of blast peak vibration, but also in making recommendations as to the choice of millisecond delays, reducing the possibility of delay overlaps and reducing the hazards of blast hole cutoffs.

Jan 1, 1980

By Frank Hammelmann, Peter Reinders

This paper briefly describes the past history of blast management. A modern blast management suite is then presented which demonstrates the current capability of the functional link between an electronic blasting system and blast design software. Finally, we look at the potential of tomorrow’s fully integrated blast management systems. From the first time blasting was introduced in mining as part of the production process, blasting technology and blast management have been interconnected. Over the past decades we have gained more recent experience with the new electronic blasting systems in mining, quarrying and construction. To start, the primary focus of electronic blasting was to increase timing accuracy. However, since then the technology has gradually developed, broadened and opened up new possibilities, including impressive flexibility in blast design and full in-situ verification of system functionality. To support this capability, modern electronic blasting systems are specifically designed to facilitate full two-way transfer of information between the office-based blast management software and field-hardened equipment. Blast management systems now comprise a suite of expert systems for planning, documentation, analysis, measurement and prediction of blasts. Within this blast management suite, the blast design software allows the transfer of the blast design information from a PC directly to the hardware of the electronic blasting system. The future development of this technology holds huge potential for the blasting industry.

Jan 1, 2004

By L. L. Oriard

he Metropolitan Water District of Southern California (MWD) supplies water to some 16 million people in a semi-arid region. Most of this water is imported. Some of the supply lines cross over the San Andreas fault, one of the most notorious and active faults in the U.S. There was a serious need for emergency water in case normal supplies should be interrupted. To fill that need, MWD had to find a reservoir site on the west side of the San Andreas fault, west of the mountains. Because of the distinctive nature of the location, it was necessary to construct a huge “bath tub” by building a dam at each end of a valley, requiring some 115 million cubic yards (88 million cu.m) of fill. In effect, two large-scale surface mining operations have been under way simultaneously. The $2.2 billion project is known as the Eastside Reservoir Project. Because of space limitations, this paper will be limited to those topics which are expected to be of primary interest to explosives engineers, principally related to large-scale rock fill production. There is not sufficient space to discuss the many diverse geotechnical questions related to site selection, geological and geophysical field testing, laboratory testing and design considerations. This brief overview may assist those who might be interested in making a tour of the project site following the ISEE conference.

Jan 1, 2000

By Midori Sakamoto, Nobuaki Sakuma, Tsuyoshi Murashita

Recently, tunnel blasting works near the residential area and existing building are increasing and environmental problems caused by vibration have become serious public concern. In order to solve these problems, blasting works have been conducted with segmented blasting and reduce advance per round. However, with these blasting, work efficiency is not obtained, and regrettably the cost and risk of accident tend to increase. We developed a new controlled tunnel blasting technique with electronic delay detonator. Electronic delay detonator can supply extremely large range of delay period which could not be achieved with conventional pyrotechnical delay detonators. We utilized advantages in initiating hole by hole over entire tunnel face at the same round. Much seismic data obtained from tunnel blasting with conventional detonator was statistically analyzed in order to find average duration time of vibration caused by a single hole initiation. Numerical simulation using sample waves from a single hole initiation was carried out in order to find an optimum delay time which can separate vibration in each hole initiation and without decreasing blast performance. Trial blasting was conducted to examine the correctness of optimum delay time obtained from numerical simulation. This blasting technique was applied to an actual tunnel construction. This tunnel is 2 lane automobile tunnel with a total length of 659 meters and internal cross section of 70 square meters. The purpose of the use of blasting technique on occasion, was the protection of fresh water reservoirs directly above the tunnel, and to keep the effect on local private houses to a minimum. The vibration level against this station was limited under 20 mm/see P.V.V. With this blasting, the tunnel construction was completed without exceeding the limited vibration level, with minimum cost and construction time.

Jan 1, 1998

By Adrian Moore, Alan Richards

Time window techniques that limit the explosive charge mass being fired within a specified time window (commonly 8 milliseconds (ms)) have been used for many years and are widely accepted by explosives engineers. The 8 ms time window may be relevant for controlling ground vibration for small blasts at close quarters in a high frequency vibration environment. For controlling ground vibration from blasts in a low frequency vibration environment an 8 ms separation between blastholes is arbitrary and meaningless. The 8 ms time window was never intended as a means of controlling airblast. The use of time window techniques will, in many instances, result in airblast and ground vibration levels that are substantially greater than planned, with unfortunate outcomes. The uses of time windows that are inappropriate have been well explained in previous papers. This paper gives further examples of blast designs that satisfied time window considerations but have resulted in substantially greater airblast and ground vibration levels in certain directions, due to wavefront reinforcement or the combined effect of drilling pattern and delay sequence. Techniques that identify wavefront reinforcement, due to the combined effect of drilling pattern and delay sequence, can assist explosives engineers to avoid blast vibration problems that result from inappropriate time window techniques.

Jan 1, 2002

By P D. Katsabanis, W Roberts

Commercial explosives exhibit non ideal behaviour which is very difficult to model. The fume spectrum produced by commercial explosives apart from its practical significance for underground mining is of great theoretical importance since it reveals information about the chemistry of the detonation process. Emulsions, watergels and dynamites were tested under various degrees of confinement in an one cubic metre closed chamber. Sand, concrete, steel and copper pipes were used to alter confinement. The degree of confinement was found to significantly influence the quantity (litres/kg of explosive) and the relative proportions of toxic and non-toxic fumes (percent of total fume measured). These results lead to further confinement testing using various rock materials. Fume results, and thus detonation performance were found to be dependent on the type of rock material used for confinement. Materials such as dolomite, limestone, and granite were found to result in a relatively high detonation efficiency of the subject explosive as shown by the distribution of detonation fume products. Conversely materials such as sandstone, talc and massive sulphide resulted in fumes suggesting low relative detonation efficiency. Fumes appear to be a sensitive indicator of the completeness of reactions occurring within the expansion zone of the composite emulsion explosive, while the detonation velocity is relatively insensitive to small variations in confinement. Estimates of sonic velocities of the confining rock materials were found to show no correlation with VOD results. However good correlation between fume results and sonic velocity suggests that the performance of an explosive as indicated by the resulting fume spectrum is affected by the degree of confinement.

Jan 1, 1992

This paper describes the circuit simulations based on SPICE of the SDI Electronic Detonator System at the system level. SDI is launching the Electronic Detonator System with a robust serial protocol exhibiting great ease in field usability and deployment. Programmable delay time with increment of 1 ms up to 10s is possible. Bus length of up to 2 km containing 1600 detonators can be utilized. This system was analyzed using SPICE simulations and an Excel-based firing model spreadsheet. The effects of wire diameter, resistivity, detonator leakage characteristics, blasting array topology (lumped, linearly distributed or branched) were simulated using the firing model. Such spreadsheet is instrumental in determining the blasting topology of any given detonator number and bus wire diameter or resistivity. Initial simulation results were interactively coupled back into making the serial protocol more robust during typical mining conditions.

Jan 1, 2006

By B Mohanty

Several parameters such as, Energy, Strength, Brisance, Impulse, and Bubble Energy, are in common use in the explosives industry today to rate commercial explosives in terms of blasting performance. However, this multiplicity of terms, their frequent interchange and their purported one-to-one correlation with expected performance have given rise to a considerable amount of confusion, and have often resulted in unrealistic rating of explosives. In this paper, various theoretical and experimental methods of estimating energy and performance of explosives are discussed and their relative merits examined. These methods include, Computer Code Calculations, Cylinder Test, Trauzl Test, Ballistic Mortar Test, Underwater Test and Model-scale blasting. It is shown, in the light of actual blasting process, that such measures cannot be considered accurate indicators of expected blasting performance as the properties of rock to be blasted are either totally ignored or only partially accounted for in these methods. It is also shown that no single technique alone among those currently employed by the explosives industry can lead to realistic rating of explosives in terms of expected blast results. The need for the adoption of a two-tier rating system, one based on chemical potential "energy", and the other based on blasting "performance" is proposed, and specific approaches to achieve this objective are outlined.

Jan 1, 1981

By Brent Blanchard

The use of explosives to safely fell structures can be traced back over 300 years. Since then, dozens of chemists, inventors, blasters and demolition experts worldwide have played prominent roles in the evolution of what has become the modern-day explosive demolition industry. In America, one of the earliest applications of explosive demolition occurred in response to the great fires of San Francisco, where homes and businesses were blasted with gunpowder in a desperate attempt to create firewalls. Later in the 19th century, inventions such as nitroglycerine, dynamite and blasting caps made structural blasting a safe, efficient alternative to conventional demolition methods. The 20th century brought the first experiments in shaped charge technology, and this, combined with developments in portable seismology and non-electric delay systems, allowed an ever-expanding variety of structures to be explosively felled by demolition experts throughout the country. The 1950s and .60s brought a new wave of commercial structural-blasting entrepreneurs (several of whom are still active today), and their efforts towards improving adjacent-structure protection and public relations beget the felling of large commercial buildings in dense urban environments. By the late 1980s, publicity-driven motives were gaining greater influence in the decision to .implode. various structures, and the transformation of blasting operations into promotional spectator events played a role in several injuries and fatalities. Since that time, however, a renewed sense of responsibility practiced by most blasting firms and project officials has resulted in the safe, successful completion of hundreds of recent endeavors. In sum, what appears today as an efficient, economical - and visually spectacular - way to demolish structures has its roots in developments of the past several centuries

Jan 1, 2002

By Hung Tran, Denis Fleury, (Ken) Qian Liu

Pastefill technology has gained an increasing popularity over the past decade. The main advantages are: environmental performance (mainly in tailings disposal), low operation costs and ease of operation, as well as homogeneous properties. However, its weaker nature compared to other types of fill makes it more vulnerable to blast damage. In the last few years, Louvicourt Mine has experienced some cases of pastefill sloughage during the mining of secondary stopes. In order to reduce pastefill sloughage, some studies have been undertaken to investigate the causes and to find possible solutions by looking at stope design, extraction sequence, ground support and blast design. This paper presents the results of a blast damage study carried out at Louvicourt on the 860m level. The instrumentation included vibration monitors (using 6 sets of triaxial geophones grouted in the pastefill), a borehole camera to observe the damage in the pastefill, and a cavity monitoring system for three-dimensional surveys of the blasted stope. The test stope was mined out by four slot blasts and three mass blasts. Most of the damage was created by the mass blasts. It was found that the accumulation of ground vibration was mainly due to the low seismic velocities in the pastefill and the relatively tight delay between blastholes. In addition, there was a substantial difference between the critical PPV in the confined and unconfined pastefill. In practice, these findings have led to modifications of blast design to minimise the exposure time of pastefill walls to air. Such modifications included changes of blast sequence in secondary stopes and delay layout between heavily loaded blastholes. Over the paste two years, the implementation of new blast sequence has shown encouraging results in terms of reduced pastefill sloughage and dilution.

Jan 1, 2000

By Zheng Deming, Li Hongwei, Lei Zhan, Dai Chunyang

This paper introduces the application of a digital electronic detonator in the demolition blasting of largescale (LS) and long delay time (LDT) frame-shear structure buildings. The whole building to be demolished by blasting is an L-shaped frame shearing structure. Some parts of these buildings have a large length along the direction of collapse, so the detonation delay of the column is longer. To ensure the building is successfully blasted and demolished, a digital electronic detonator detonation system is adopted. In the design of the detonating network, full use is made of these characteristics of the digital electronic detonator, such as flexible installation, high precision of delay before blast, and dedicated testing equipment to check the reliability of the network. These advantages ensure the damage of the load-bearing structure is within the blasting gap and that the accuracy of the collapse time of the building, which not only guarantees the collapse effect of the building, but also provides strong technical support for improving the intrinsic safety of the blasting operation and the supervision of the flow direction of the detonation, these research be provide reference for the application of digital electronic detonators in similar projects.

Jan 1, 2019

By Mark S. Stagg, Steven V. Crum, Stephen A. Rholl

As part of its ongoing research concerning rock fragmentation by blasting, the Bureau of Mines has undertaken a series of test blasts where six cylinder-shaped pieces of granite rock were fragmented using high explosives. The tests were intended to: 1) Establish a dataset that could be used in the development and verification of theoretical models that simulate rock blasting and 2) To add to the fragmentation data currently being collected by Bureau researchers. The cylindrical geometry was chosen so that the fragmentation could be directly compared to two-dimensional computer simulations that assume an axisymmetric configuration as well as more sophisticated three-dimensional models. The granite cylinders, Carnelian granite and Charcoal granite, ranged in size from about 0.46 meters (18 inches) to 0.58 meters (23 inches) in diameter by 0.91 meters (36 inches) to 1.52 meters (60 inches) in length. Physical rock properties tests performed on the Charcoal granite cylinders indicated that the rocks did in fact have similar physical characteristics. PETN-based detonating cord and dynamite were used as the explosive charges and estimates of the values of some important physical properties are given. For the first five tests, the blasted rock was contained by a heavy rope mat suspended inside the Twin Cities Research Center's blasting shelter. The fragments from each of these shots were sorted and weighed to determine the corresponding fragment-size distributions. Even though different types of granite and cylinder sizes were used, similar fragment distributions were produced from shots that used a similar explosive, in this case the PETN-based detonating cord, and comparable burden-to-charge diameter ratios. Significantly coarser fragmentation was produced from a blast that used dynamite as the explosive charge. Fragment velocities were calculated using photographic data from the sixth test which was shot unrestrained in a quarry and filmed with high-speed cameras.

Jan 1, 1990