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Blast performance is related to rock structure and strength, as well as to factors such as site geometry, drill patterns, explosives loading, firing sequences and delays.

Jan 1, 1986

By Jerry R. Wallace

Infrastructure improvements and industrial plant expansion and modernization often require rock blasting within 20 feet of existing structures. In many instances trenchlines must cross beneath existing in-serv1ce utility lines.

Jan 1, 1994

By Paul D. Dupree

This paper discusses the drilling and blasting techniques used in blast casting at a large western coal stripping operation.

Jan 1, 1986

By Rajesh Sonkar, Sanjeev Kumar

The deployment of Dragline machines in opencast coal projects involves huge capital expenditure as well as operating costs. The mine operators always endeavor to ensure smooth excavation of material by the Dragline machines while meeting the major objectives of safety, minimal disturbance to environment and optimal operating costs. Optimization of fragmentation through well designed blasts is fundamental in meeting part of the objectives is good fragmentation of rock or mineral proposed to be lifted by the Dragline machine. If the overburden lying over mineral is not properly fragmented, it may result in formation of ‘Toe’ the removal of which is the most arduous task in opencast coal mines. The mine operators always endeavor to achieve best possible results in blasting to ensure smooth operation of the high cost Dragline Machine. However, despite continuous efforts by the blasting engineers involved in bench blasting for the machine, the formation of ‘Toe’ is an ever nagging problem faced in large opencast coal projects eventually reducing the overall operational efficiency of mining.

Jan 1, 2011

By Tapan Goswami, Geoff Keith

"At Bulga Coal, the objectives of drilling and blasting are to maximise safety and to minimise the totalcost of mining. A recent audit of two overburden blasts established that the standard of drilling and blasting is excellent. No apparent hazards were identified. Laser profiling showed that highwall free faces are reasonably planar with some exceptions, thereby promoting uniform burden distances along front-row charges. However, in three isolated areas along one face, small burden distances existed. The mean and the standard deviation of errors in the collar positions of front-row blastholes was found to be 0.3 + 0.03 m. A borehole video camera was used to show that blastholes did not feature open bedding plane partings, cavities or damage produced by the blast in front of them."

Jan 1, 1999

By Lyall Workman, P D. Katsabanis

Energy released by the explosive is typically partitioned in brisance, heave and losses. The fact that energy released in the P-V expansion curve below a certain point is lost has resulted in the concept of available energy. Through simple calculations it is shown that energy released at pressure levels thought to be low, amounts to a significant proportion of the total energy value. Furthermore, throw calculations indicate that the assumed loss of that part of energy does not justify practical results. Loss of energy at the low pressure levels may also not be justified from the fragmentation point of view as pressure levels below 1 kbar are enough to extend radial fractures around a borehole. Finally the equation used for the P-V behaviour of the explosive gases is important in throw calculations. Simplified approaches may not reproduce the performance of the explosive which is not characterized only by its energy content.

Jan 1, 1998

By P. Ross, O. Rielo, P. Katsabanis

Selection of delay times to optimize fragmentation has been a controversial topic among researchers and blasting practitioners. The paper reviews all available experimental information, ranging from small and medium scale tests in geologic materials to small scale tests at the laboratory and synthetic materials, simulating rock. Tests have been re-analyzed and discussed in terms of the information they present and the limitation of the testing environment in representing actual conditions. New results obtained from blasting experiments in specimens made of a grout have provided a clear picture of the effect of delay on fragmentation. The grout used has a strength of 60 MPa (8700 psi), density of 2.5 g/cm3 and P-wave velocity of 4000 m/s (13100 ft/s). Each block was placed in a yoke to eliminate unwanted reflections and the desired delay was obtained using the appropriate length of detonating cord between holes or sub-millisecond electronic detonators. Delays ranged from 0.1 ms/m (0.03 ms/ft) of burden to 16 ms/m (4.9 ms/ft) of burden. Fragmentation was obtained using screen analysis of the collected fragments. Delay time has been shown to be a significant parameter affecting fragmentation and back break. Generally larger fragments and less back break was observed at short values, while fragmentation somewhat deteriorated at significant delay times, compared to what was observed at intermediate delay times. The work is now extended to include the effect of energy partition on fragmentation as well as the effect of initiation point and coupling ratio.

Jan 1, 2014

By Sam Taoum, Omar Riahi

Few tools allow for accurately tracking ore dilution after blasting. Existing methods often rely on data analysis or linear interpolation of velocity, which can be imprecise and less effective in varied geological settings. A promising alternative is the use of numerical simulations, which involve complex mathematical calculations incorporating real physical data about explosives and geological characteristics. These simulations can model blast-induced fragmentation and subsequent ore dilution with greater accuracy, providing detailed insights into blast dynamics by considering factors such as explosive type, blast pattern, and rock properties. Numerical simulations integrate data from sources like seismic sensors, blast monitoring equipment, and geological surveys, offering a holistic view that single-method approaches cannot match. By simulating different scenarios, mines can predict the outcomes of various blasting strategies, optimize blast designs to minimize ore dilution, and maximize recovery. Advanced numerical simulations enhance the prediction of fragmentation distribution and size post-blast, crucial for effective dilution control and maximizing ore recovery rates.

Jan 21, 2025

By Norman Kramer, Roger Keller

The authors would like to thank Austin Powder Company for their technical support and input, specifically Stephen Harris, Jason Ryan, and John Capers of Austin Powder, without whose support this paper would not have been possible. Thanks are also extended to Nick Francis of Sandia National Laboratories and Jim Houseworth of Duke Engineering for their input regarding Performance Assessment.

Jan 1, 2000

By Shonn K. McNeill, Joshua Micah Hoffman

Security engineering is similar to other forms of engineering – the design is guided by the loads, materials, and desired function. For facility design, the load is the threat. Facilities that are designed with considerations for explosive hazards are designed with a shot, or series of shots, of a given size and distance from key locations. These facilities range from office buildings and industrial sites in developed nations to military and police stations in contingency areas. The challenge is the design shots are not often communicated to facility owners and managers. If the hazards change, whether it’s due to an increased capacity to cause damage by a threat or a decrease in capacity by a structure, not knowing the design shot means not knowing if security design needs to change. Blast modeling is an engineering tool that can be used to reverse engineer what a facility is suitable for, as well as be a tool for modifying security design for new conditions. This paper will examine military and civilian examples, including a case study of a military facility that did not know their as-built conditions and had to be rapidly closed; due to the determination their security engineering shortcomings could not be mitigated.

Jan 1, 2019

By Chris Breeds, Larry Leone, Jerry Wallace

One of the Authors was recently retained to provide a professional engineering analysis of the potential impacts from underwater blasts used to enlarge intake tunnels at the Cheesman Dam near Denver in Colorado and to design Blast Protection Bags that could be installed in each tunnel to protect the 100- year old downstream valve structures.

Jan 1, 2012

By Tassilo Baur

In the motion picture/television industry and to some extent in the entertainment industries in general, there is often a need to use energetic materials to create special effects as part of a production which travels, generally by truck. This can in certain instances create unique compliance challenges given that a production may change its filming location daily or even more often

Jan 1, 2009

By Michael Wieland

The thrust of this report is to overcome some of the technical deficiency in the scientific methodology that correlates the work output during a charge explosion to the resulting toxic fumes. Thermodynamic work-principle models yield (undissipated) shock and heave results for shooting underwater and in rock stratum with related toxic fumes. Underwater circumstances yield reliable test data for the work process, though questionable or no fume results. Work-output measurements in rock shots remain difficult if not intractable, though some fume reports exist. Underground tests with thick-wall metal pipe bombs yield consistent toxic fumes trapped within the test chamber. The work output, rendered as fragment kinetic energy, can be inferred from the well-tested theory of R. W. Gurney, originally designed for military ordinance. Therefore a work-principle model for cylindrical pipe bombs was developed to predict fragmentation work output and reaction-zone fumes, permitting the double comparisons to reported and inferred results.

Jan 1, 2010

By W. L. Saunders

RBH Note: In the early days of drill & blast tunneling the jobs utilized large crews of drillers and muckers. Advance per round was limited (typically around four feet) but two rounds per 8-hour shift were expected, around the clock. The scene after a shot must have been chaos, with the muckers expected to quickly make space for the drill setup. Makes one wonder how much time was allowed for the smoke and fumes to clear. Note the headgear of the tunnelers.

Jan 1, 2011

By G. Walsh, L. Wolkovitch, A. Savage, V. Romero, T. Zimmerly, G. Imahara, J. Hyneman, K. Byron, D Tapster, S. Belleci, J. Metzger, M. Stanley

Testing was conducted at the Energetic Materials Research and Testing Center for the MythBusters on three separate occasions. This testing included (1) an experiment designed to create diamond from graphite using the shock and pressure of a detonation, (2) the flattening of a car using a steel plate driven by a rocket sled, and (3) the bifurcation of a car also using a rocket sled. All tests were successful; diamond was produced following the detonation of ANFO, and extracted from a graphite / cobalt matrix. A plate was accelerated to 646 mph (1040 km/hr) using a two-stage sled system loaded with 5” (12.7 cm) high velocity aircraft rockets (HVAR) into a car, which was subsequently demolished. Finally, a steel wedge was pushed to 541 mph (871 km/hr) by a one stage sled using HVAR rockets, and was able to cleanly cut a target car in half.

Jan 1, 2010

By C. Breeds, K. Jeremiah, E. Jennings

Washington State has a well developed set of blasting regulations which have been promulgated by the Department of Labor using extensive stakeholder input, not only from citizens but also from manufacturers and representatives of IME, blasters in charge, blasting engineers, blasting companies, local and federal law enforcement agencies, fire officials, and local and state government representatives. WAC 296-52 therefore provides a foundation or platform for developing city ordinances for Washington State cities should a City wish to do so. On the other hand, Oregon’s code is based on OSHA 1926, Subdivision U, Blasting and the Use of Explosives which provides scant direction regarding the modern use of explosives. Reference is also made to ODOT Section 00335 - Blasting Methods and Protection of Excavation Backslopes. This paper examines two separate programs that have been developed by two Cities, one in Washington State and one in Oregon to further regulate blasting inside City limits and discusses why the lack of a regulatory foundation made one approach more difficult than the other. One of the authors was retained by the City of Kennewick, WA to develop their ordinance and has more recently followed and reacted to a pending ordinance for the City of Redmond, Oregon. The paper will compare and contrast the different approaches and comment on the reaction from both Blasters and the public. We also present a case study that involved blasting in an urban area of Oregon to prepare a foundation for a water tank. Controlled Blasting was carried out within 70-ft of residencies and within a community that had expressed reservations regarding blasting even though the work would make a significant contribution to the betterment of the community. Pre-construction surveys of residencies located in a large area surrounding the site were performed and a well-planned blasting program was carried out. Residencies were subject to vibration levels that were monitored using six seismographs that surrounded the site and these units measured vibration levels that were significantly lower than allowed by statute. There were complaints triggered by individuals reactions to blast vibrations which validated commonly held models of human perception but no damage was caused by the Blasting.

Jan 1, 2024

By Per-Anders Persson

TIGERWIN, now on CD, is a user-friendly personal computer code (running under Windows) which determines the detonation and expansion state of an explosive from its known chemical composition. TIGERWIN is intended for users in the mining and commercial explosives industry who do not routinely program or run Fortran codes. The code allows the user to open a window on the computer screen and enter the initial density and the weight percentage composition of an explosive, ingredient by ingredient. Alternatively, the code can balance the composition with one or more ingredient percentages fixed, while proportionally adjusting the others automatically to give a total of 100%. The equation of state and its parameters can be user-selected from several proven and tested versions of the BKW, the JCZ, and the ideal gas equations of state. TIGERWIN allows the user to select several options for different additional calculations, such as determining the constant volume explosion, the Chapman-Jouguet (C-J) point, the detonation Hugoniot, the expansion isentrope from the C-J point, and point calculations with selectable specific volume and temperature. Additional options include calculations of detonation data with one or more ingredients partially reacted, assuming either temperature equilibrium between reaction products and unreacted material, or keeping the unreacted material “cold” at the initial temperature. Thus the code can run both ideal and non-ideal detonation calculations. The code automatically saves the input and output files in a separate directory for future reference. The output from several calculations can be displayed and printed in the form of a comparison table. In it, the key results of up to five calculations with different explosive compositions can be compared. The results from an individual calculation can be displayed graphically and printed with expansion work, pressure, or temperature as functions of specific volume. A complete listing of the details of the calculation results, similar to those from the original Fortran Tiger calculations, can also be displayed and printed. No computer experience is required to run the code and workshop participants are encouraged to bring in their own formulations to try out on TIGERWIN

Jan 1, 2000

By David E. Siskind

In the period 1989 to 1994, the U.S. Bureau of Mines assisted the Office of Surface Mining, Reclamation and Enforcement (OSM) in studying a high-complaint situation near an active surface coal mine. As part of a review for its project report, the Bureau had to address issues on the adequacy of the safe blasting criteria and analysis procedures in its 1980 report RI 8507, Structure Response and Damage Produced by Ground Vibration From Surface Mine Blasting.

Jan 1, 1996

By Kenneth Faroni, Catherine Aimone-Martin, Thomas Gelormino

A blasting improvement program began in 1985 at two traprock quarries in Connecticut to reduce the levels of ground motions and airblast measured at residential structures surrounding the operations. The quarries are situated within town limits, adjacent to a number of historical and other structures. Although blasting vibration amplitudes were found to be far below those that could produce cosmetic defects in structures, they were perceived to be the cause of structural defects observed by homeowners. Based on a comprehensive * review of blasting practices in place during1985, an extensive vibration monitoring program was implemented. The initial study included the instrumentation of selected residential structures to record and analyze strains imposed within structures from quarry blasting, environmental changes, and from daily household activities. A comparison of the results was made with the results reported by the U.S. Bureau of Mines in 1980. The highest strain imposed in drywall from blasting (13 J_I strain) was 12% and 1% of the highest strain levels recorded for normal household activities and temperature changes, respectively. The present philosophy in production blasting is to attempt to keep vibration amplitudes as low as practical by implementing state-of-art blasting control techniques. Currently, blasting seismographs are placed in a circular manner around each quarry, providing production blast vibration records for 360 degrees of coverage at distances of 2500 to 4000 ft. from blasting operations. Seismograph and production blast records are analyzed each year and become part of a Blasting Improvement Plan submitted to the local zoning commission as part of the annual operating permit process. This paper summarizes the results of previous vibration monitoring programs and outlines the modifications made to blasting practices to minimize the levels of ground motions and airblasts. The public relations efforts and standard corporate procedures used by company personnel to address all blast related complaints and alleged damage claims since 1985 are also discussed.

Jan 1, 2000

By Jorge Alvarez

In a large-scale open-pit mining operation, continuous efforts are made to control damage to the slope walls. An essential tool in this effort is determining the PPVc (critical peak particle velocity) in areas of interest. By knowing this value and generating criteria, drilling and blasting designs can be established to reduce vibrations that affect wall construction. It is crucial to understand that the PPVc changes as different mining phases develop, especially due to exploitation on the benches, which leads to vertical inherited damage. Therefore, it is imperative to regularly update the PPVc based on field tests that provide accurate data. With this information, vibration damage criteria can be established, and drilling and blasting techniques can be designed to minimize the impact on the remaining rock mass. This document presents a methodology for generating scaled criteria that best represent the reality of the rock mass.

Jan 21, 2025