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By Tyler Rockley, Greg Bailey

This paper is an engineering case study of a blast performed on a highly weathered sandstone isthmus in an area sensitive to vibration and airblast, the challenges associated with such a blast, the methods used to understand rock characteristics, the blast design considerations and a discussion of the blast results. The purpose of the blast was to remove approximately 12 feet (3.7 m) of surface material in order to install a pumping station. The isthmus provided several challenges due to the weathering of the rock and multiple open faces with surrounding water. The highly fractured and weathered rock was subject to about ten years of freeze thaw cycles, influx of water and seasonal submersion. As such, all actual rock conditions were indefinite, including fracturing, rock properties, degradation and competency. The isthmus also had immediate neighbors who were unused to the environmental effects of blasting. To help continue to keep the social license to operate in the area, it was important to reduce the ground vibration, blast duration, dust and airblast. These factors required a better understanding of how the rock would respond to blasting. In order to do this, test blasts were performed on the same geologic formation in a different location of the quarry that was less sensitive to vibration and airblast effects, allowing the blast parameters and design to be verified and refined. The test blasts were performed while monitoring vibration, air blast, material movement and overall shot performance, and the blasting parameters were adjusted accordingly. The isthmus blast was performed based on the final design from these test blasts. The drilling and loading of the shot all met acceptable criteria and were comparable to the test blasts. The blast performance, however, was not as expected; the depth impacted by the blast was substantially more than expected. Since the test blasts were performed in the same formation, but in material that was significantly less weathered than the isthmus, the actual effect of this weathering was the only difference between test blasting and the isthmus blast. Thus, these results can be used for future reference to highlight the effects of blasting such highly weathered rock and help instruct the blast design in similarly complex conditions.

By John A. Davis, David W. Brunton

(Excerpts, pp 157-160) The usual means of firing blasting charges, especially in tunnels and adits in the Western States, is by the use of a safety fuse. The term safety fuse originated from the fact that when properly used under working conditions this fuse burns at a uniform rate and does not flash or explode, as was often the case with the means employed for igniting blasting charges previous to its invention; but the term is somewhat misleading, because the fuse is not, nor has it ever seriously been claimed to be, safe for use in gaseous coal mines. The fuse used for tunnel work is composed of a core of gunpowder surrounded by various layers of waterproofing material.

Jan 1, 2015

By Q Liu, P D. Katsabanis

The energy output of crushed AN/FO, crushed AN/FO mixed with Aluminum (5%, 6.4% and 9.4% A1 by mass) and a commercial emulsion explosive has been measured using a detonation calorimeter. The charges had a diameter of 10 mm and were heavily confined by a 11 mm thick copper shell. In order to achieve stable detonation glass microballoons were used in the explosives so that the density of the AN/FO charges would be around 1.1 g/cc. The charges were detonated in vacuum and the detonation products were analyzed using gas chromatography. It was found that energy values were very close to calculated values obtained by ideal detonation codes.

Jan 1, 1993

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 K. M. Kim, J. B. Kemeny

A case study was conducted with 5 shots with varying pre-blast block sizes and explosive energies. From this case study a site-specific predictive fragmentation model was developed. There are two main innovations in this study. One is using an image analysis program (Split-Desktop 3.0) on the bench face to obtain the pre-blast block size (F80) quickly and consistently. Another innovation is to utilize the Schmidt Hammer Hardness (SHH) to estimate intact rock strength.

Jan 1, 2011

By Unknown

[Executive Director’s note: According to 17th edition of the ISEE Blasters Handbook in its section on trench blasting, “...consideration must be given to the proper venting of gases generated from the blasting. Should those gases spread laterally rather than vent directly to the surface, the gases may travel underground and finally vent well outside of the planned area. Such events may be caused by the strata, soil conditions or root systems, or existing and/or abandoned utilities or other man-made structures. In the worst situation, gases resulting from the detonation such as CO2, CO, and/or NOx may travel through the strata and find their way into basements of nearby homes or businesses. The IME has recommendations on how to minimize this potential problem. Some of the points include removing the overburden and digging the rock immediately after the shot, and drilling vent holes periodically between the ditch and adjacent homes.” The Board of Directors of the International Society of Explosives Engineers has expressed its concern that blasters be made aware of the issue of migration of carbon monoxide resulting from blasting operations. What follows are excerpts from “Carbon Monoxide - The Silent Hazard”, an article that was recently included in the Safety Update, Vol. 20, No. 1, 2001, published by Nobel Insurance Services.]

Jan 1, 2002

By Luis Huaroc, Jorge Cardenas, José Salvador

One of the current challenges in mining is managing increasingly competent rock conditions within the mine-to-plant value chain, particularly when working with marginal ore grades. This study presents a case from a Peruvian open-pit operation where the mine plan projected a significant increase in rock hardness, as measured by the Axb index (parameters derived from the JK drop weight test). In response, the Drill and Blast Technical Team made efforts to increase the powder factor by reducing drill spacing and increasing the explosive charge, employing high-energy explosives (3,090 kJ/kg). However, this adjustment presented a challenge in achieving the fragmentation required to meet the target throughput of 97,500 tons/day, resulting in a shortfall of approximately 8.7% under the base case scenario. To overcome this technical challenge, the use of locally engineered ultra high-energy explosives was proposed, offering adjustable energy levels ranging from 3,210 to 3,570 kJ/kg. This solution enhanced ore blending strategies, calibrated to specific Axb ranges. The results also suggest that microfractures generated by the energetic blasting designs contributed significantly to downstream improvements. These outcomes demonstrate the value of a fully integrated mine-to-plant strategy, aligning blasting parameters with downstream processing performance to maximize operational efficiency. This solution led to a 10% increase in process plant efficiency, a 16% reduction in specific energy consumption during primary crushing, and a 13% reduction in the SAG mill. Additionally, shovel productivity rose by 18%, and the dig rate improved by up to 35%. Keywords: fragmentation, blending, high-energy explosive, power factor, microfractures, specific energy consumption and Axb model.

Jan 26, 2026

By Lifeng Li, Jhon Silva-Castro

"Signature Hole Technique is one method to assess the vibration waveform of a production blast.Methematically, it is the convolution between a prior measured waveform of a single blast hole (signature) and a given time delay sequence (comb function). Being an advantage, the inverse operation of convolution, known as deconvolution, can be used to estimate the signature."

Jan 1, 2017

By Jorge Flores, Dean Nichols

Some view quantitative risk assessment (QRA) as difficult to understand and complicated to use. They are comfortable with the proven reliability of quantity distance (QD) and question the benefits of applying QRA principles to explosive safety. In response to such questions, a review of the history of the American Table of Distances (ATD) provides insight to the strengths and weaknesses of the concepts behind QD tables. Additionally, a closer look at QRA features that are available today will reveal stunning capabilities and improved user friendliness not available previously. This paper looks at the early days of explosive safety, the use and limitations of QD, the meaning of risk in the context of QRA and discusses recent developments that knock down barriers previously hindering acceptance of QRA among regulatory agencies.

Jan 1, 2015

By Joseph Nawrocki, Margaret Hettinger, Dr. Catherine Johnson

"Optimized rock fragmentation is essential for minimizing downstream costs to mining operations.Photographic fragmentation analysis, vibration monitoring, and high-speed video all providemeasurements of blast effectiveness and supply data that allows operations to modify blasts to achieve downstream goals."

Jan 1, 2016

By Travis Watts, Chris Prater, G. T. Lineberry

Moving overburden at minimal cost is becoming increasingly important to coal mining companies throughout the U.S. The coal market is currently doing well, with an average spot coal price for Central Appalachia product (12,500 Btu, 1.2 SO2) standing at $62.00 for the week ending November 11, 2005, so it is at this time that companies stand to achieve healthy rates of return on their investments. Cast blasting is one method of blasting used effectively by some surface mining operations. This method allows most of the overburden to be removed and placed (cast) directly in the spoil pile by the use of explosive energy. With the proper design of a cast blast, a high percentage of overburden material can be directed into piles without the use of earthmoving equipment, hence increasing production and lowering the cost associated with overburden removal.

Jan 1, 2006

By Randall M. Wheeler

Computer analyses of single hole signatures are often used to help blasting operators predict the type of ground vibration effects that may be produced from production blasts incorporating various delay intervals. Frequency analyses of single hole waveforms and subsequent multi-hole waveform simulations can allow an operator to determine the best type of delay intervals to use in order to minimize low frequency ground vibrations.

Jan 1, 1989

By Thierry Bernard

For many years now electronic initiation has brought the time parameter to the centre of blast designs forever. Although this parameter existed before the era of electronic detonators, Blasting engineers or blasters could not directly handle it; technology imposed it. Only discrete values were available. Today, the fact that we can choose any detonation time for an explosive charge questions the viability of most of the rules applied for blast design. Thus, the very famous charge per delay method, that enables a level of vibration to be forecast at a given distance (“Chapot’s law”), is no longer necessarily valid when using electronic initiation. Therefore, it must be approached in a totally different manner. The KUZ-RAM formula, that allows fragmentation to be forecast, is also subject to the same distortion. The aim of this article is to show how the calculation laws used for blast design are influenced by the time parameter (sequence) and how we can efficiently make the most of this, in particular for vibrations. Copyright ©

Jan 1, 2005

By Michael David Wilkins, Paul N. Worsey

Little research has been published on stemming blast holes, particularly what happens during the process. Previous work has concentrated on the performance of the inert material to find the best way to seal the hole and retain the explosive energy, at the exclusion of determining what happens during the loading and stemming process.

Jan 1, 1998

Vibration resulting from blasting has been a source of concern from the inception of the use of explosives. As a result many investigations have been made concerning the seismic effects of blasting and at present there is available an adequate set of standards with which to judge seismically the damage capability of a blasting operation.

Jan 1, 1976

By Jim Breedlove, Stephen P. Case, Mike Fabio

To meet salt production needs over the remaining life of the Cayuga Mine at Lansing, New York, the Salt Division of Cargill, Inc. decided to build a new underground screening plant. The new plant required a chamber 50 feet wide by 250 feet long and nearly 70 feet high. On advice of their mining contractor, Dynatec Mining Company, the company chose an ingenious excavation method similar to sublevel stoping. This method eliminated the need for an access ramp, reduced equipment needs and excavation time substantially.

Jan 1, 1996

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 Adrian J. Moore, Alan B. Richards, Rob Evans

Air and ground vibration from blasting is influenced by the delay pattern that is used. Wavefronts from blastholes fired in a blasting pattern can combine in certain circumstances to give increased blast vibration levels. A simple computer model has been developed which shows the combined effect of wavefronts from a multi-hole blast and identifies if wavefront reinforcement occurs, and permits delay patterns to be designed which will avoid or reduce wavefront reinforcement.

Jan 1, 1994

By SMF Hossaini

With the aim of a clearer understanding of the applicability of existing empirical equations for blast induced ground vibration, an investigation has been conducted on three mostly applied forms of such equations. The effect of explosive type on the applicability of these equations has been assessed by analysing 44 sets of data produced by using two types of explosives, namely ANFO and slurry explosive, in an open pit coal mine. The analysis of the data has revealed that the type of explosive affects the applicability of the criteria of the three equations. All three criteria have better correlation with the data of shots in which ANFO was used than the shots with slurry explosive. However, the applicability of one of the criteria is reduced, by far, only by replacing ANFO with slurry explosive for the same ground conditions. It was also found that one of the parameters of these criteria (i.e. “k”) is significantly sensitive to the type of explosive in all the three equations. The degree of influence to the values of “k” obtained by the variation of explosive from ANFO to slurry explosive in the three equations is 76.3%, 811% and 39%. This implies that “k” is not only dependant on ground conditions, as stated in most previous publications, but is also strongly a function of the type of explosive.

Jan 1, 2004

By Dr. Anthony J. Konya

The modern era has seen a boom in virtual training platforms. This study details the effectiveness & applicability of online training in comparison to in-person training for the drill & blast industry.

Feb 1, 2020