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By A. S. Romphf, C. K. McKenzie

Recent full-scale field studies involving single-hole charges fired to free faces under a wide range of operating conditions have delivered precious insights into airblast characteristics and propagation. The field tests involved production blasthole diameters in the range 89 to 406 mm (3 ½ to 16 in), bench heights in the range 9 to 24 metres (30 to 79 ft), burden ratios (burden/hole diameter) in the range 14 to 51, stemming ratios (stem height/hole diameter) in the range 11 to 36, explosive types of ANFO, heavy ANFO and pumped emulsion, and both solid-column and double-decked charge configurations. Around 700 measurements of peak amplitude and wave shape were made in all directions (0 to 360 deg) from the free face, from 38 single-hole tests in nine North American operating quarry/mine environments. The most striking observations were the strong dependence on directionality of the wave propagation parameters and wave frequency, the consistency of wave shape which resembled the modified Heelan wavelet, and the occasional appearance of distinct, multiple pulses from single events, shown to be echoes/reflections from quarry faces. In-hole deck charging failed in this study to achieve expected peak overpressure reductions, with the peak overpressure levels in Pascals/psi/millibars being approximately 40% higher than the as-charged weights. Inter-deck delay times in excess of around 25 ms are required for effective reduction of peak overpressure levels from front-row holes. Simple linear-superposition models based on synthetic wavelets applied to large production blasts produce composite waveforms which capture the important features of the actual pressure-time history, and correlate well with measured waveforms.

Jan 26, 2026

By Jim Peterson, Ricardo Freire, Mason Biernat

Variable nature of rock and face conditions, varying execution and changing nature of blasting are making ongoing optimization challenging. Intelligent planning and on-going analytics are required to mitigate variability and convert blasting into a predictable outcome by use of technology. Blasting operations generate a huge amount of data which can be used intelligently for optimization. In this paper, details are provided of a system which is used for blasting data collection in the field – Key details around blast parameters, explosives, initiating system details, video, photographs, vibration and fragmentation are collected in a cloud-based platform. Data can also be collected through a mobility device in the field (even without internet connectivity) and synchronized with cloud-based system. Also, data from various sources can be imported in excel formats in the software including from upstream and downstream processes from blasting. App also gives indication about exceeding of vibration, air blast overpressure, fragment size etc. Thus, making it possible to perform QA-QC before charging and deciding initiation timing and sequence at the blasting site. The data can be processed and analyzed to spot trends, help predict events, and formulate strategies at the design and execution stage. Data gathering of blast parameters, explosive used processing and analysis can be used to optimize operational efficiency, improve safety and environmental controls.

Jan 1, 2019

By AK Chakraborty, AK Raina

Burden of drill hole is third most sensitive parameter effecting the ground vibration in blasting apart from maximum charge per delay and distance. Various types of burdens can be seen in practical bench blasting situations. Burden can be expressed as drilled burden and initiation burden. Drill holes may have various front row burdens (toe burden), which may be different from the designed burden. In order to ascertain the impact of front row burden as well as the initiation burden on intensity of ground vibration and air overpressure experiments were conducted in sandstone overburden benches of an opencast coal mine and limestone quarry. Blast trials were carried out in cognisance of both drill and initiation burden while keeping all other parameters constant. Effect of front row burden was also extensively studied by keeping almost all other parameters constant. The results of the study reveal that there is substantial influence of front row burden on the vibration and air overpressure. The statistical analysis of vibration and air overpressure data with drilled burden and initiation burden gives significant evidence that the level of peak particle velocity of vibration (Vmax)) is reduced by reducing effective burden with modification of initiation. Data analysis carried out for air overpressure versus initiation burden shows that reducing effective burden with modification of initiation results in increasing the level of P. The study reveals a qualitative assessment of the influence of burden on the blast induced vibration and air overpressure. The study also recommends to modify the initiation pattern to reduce the effective burden in order to reduce the vibration, without disturbing the fragmentation.

Jan 1, 2004

By Richard G. Burdick

The use of explosive charges for generating seismic energy has been around for a long time. For oil-field work or crustal studies, when the target of interest is many thousands of feet deep, the surface waves and similar phenomena are of little consequence. In mining applications, however, when the target is a few tens or hundreds of feet deep, the return signals are often masked by these waves and an accurate interpretation is difficult or impossible.

Jan 1, 1981

By Paul L. Matrin

This paper will discuss the recent and on-going drill and blast optimization measures at the Sparkhule Limestone Quarry, which have resulted in a 44% reduction of drill and blast unit costs per ton of broken limestone. This amounts to approximately $240,000 of drill and blast saving per year at current annual production rates of about 2.5 million tons (2.3 million tonnes) total material shot. The reduction of drill and blast costs were accomplished by a detailed and controlled in-the-mine drill/blast experimentation and cost evaluation using 8 different blast pattern designs and shots totaling approximately 267,000 tons (242,200 tonnes) of shot and mucked material. A careful review of the geology of the deposit was performed to determine the different rock classification/strengths/structural properties and to adjust blast designs to optimize fragmentation for the different rock types. Equipment loading productivity and crusher throughput performance were monitored as part of the evaluation process to assure that an optimal fragmentation of broken rock was achieved with the new blast designs. The study included the review of bulk explosive and accessory selection criteria (ammonia nitrate/fuel oil mix - ANFO, mini prills (high density ANFO), sensitized and un-sensitized emulsions at a 30% emulsion/70% ANFO blend), blast pattern design, charge diameter and the cost of drilling. Laser profiling technology was used to assure proper bench heights, stemming and sub-drill footage and front row burdens. High speed photography, video and still photos were taken of the different designed shots to assist in the evaluation of the performance of each blast. Powder density checks, size distribution, back break, detonation velocity and pressure measurements were taken. Different borehole diameters were used for the drill optimization study and drilling cost and productivities determined. A detailed cost comparison between in-house blasting and complete shot service was prepared to evaluate if shot service is a cost effective alternative to current in-house loading and blasting including a review of the new and pending United States Bureau of Alcohol, Tobacco and Fire Arms (ATF) regulations and associated owner costs/risks and potential benefit of shot service.

Jan 1, 2004

By Tom McDonald, Rodney Burke

As mining progresses in the West, the depth of material has increased, making highwall stability a major factor in safety and production. The Jim Bridger Coal Mine has made highwall stability a priority, concentrating on safety as well as increasing and improving production. Overburden depths are increasing dramatically; the geological environment consists of medium to soft material, faulting, water, and current pit alignment not favorable to joint planes. Angle drilling the presplit at 20 degrees became necessary as vertical presplit drilling produced wall failures.

Jan 1, 1997

By Qi Jinduo, Gong Min

On the basis of actual parameter of wall control blast in Nanfeng mine, China, the process of dynamic stress changing between two column charges was studied recently for a presplit-cushion blast by holographic photoelasticity. In the experimental model, two holes were simultaneously detonated from both ends (four ignition points). The bottom of the holes were loaded more than other parts (heavy charge). Under these conditions, four consecutive isochromatic fringe patterns at different times were acquired in one loading run, and the characteristics of the stress distributions were compared at different places and times in the holes. It was found that interaction types of stress waves vary along the holes. The theory is posed that the stress wave which is formed by the interaction of earlier producing P wave and later S wave along a distributed line charge is the most important part in all stress waves. Research indicates that a heavy charge in the bottom of the holes is crucial to producing a presplit-cushion effect at the bottom. "End Effect" doesn't affect the magnitude of stress along linking lines between the bottoms. The chief fields of the "End Effect" are also explained in the paper.

Jan 1, 1998

By Robert Hopler

RBH Note: At the time of this price list the handwriting was already on the wall regarding the ultimate breakup of the company under the Sherman Anti-Trust Act. The brand names Atlas and Hercules, noted on page 3 of this pricelist, would become the names of the new companies created from du Pont.

Jan 1, 2012

By W. J. Birch, R. Farnfield

Nuisance caused by perceived high vibration levels as a result of blasting on quarries and opencast coal mine is now the number one environmental concern of residents living adjacent to such operations. The intrinsic nature of blast vibration monitoring and prediction is that it is impossible to accurately forecast the vibration levels that will be experienced by a given blast at a given location. Thus it is that a statistical approach to the problem is the only viable option. Unfortunately, persuading local residents living adjacent to a project that requires blasting that this is the best way of safe guarding both their homes and their quality of life is not an easy task. Thus routine monitoring involving both operators and regulators play a key role in building trust. However, public confidence is often shaken when regulators and operators use two different blast monitoring instruments side by side to record a blast at a local resident’s house and arrive at different results. To make certain that this does not happen in future, what is needed is a protocol that ensures that any two different blasting seismographs give the same peak particle velocity values at the same observation point. To do this all the equipment manufacturers, regulators and relevant professional explosive engineering bodies need to be involved.

Jan 1, 2014

By Matthew Graham, Tapan Goswami, Geoff Brent

In dragline coal mining operations, throw blasting is used for the controlled placement of overburden to maximise coal exposure rates or to minimise overburden removal costs. This may necessitate sacrificing thin coal seams, generally less than one metre in thickness, which are often present in proximity to the main coal seam. This represents not only a significant loss of potential revenue and profit but also a waste of a valuable energy resource.

Jan 1, 2010

By Jason Rock, Rob Thompson, Lee Julian

Reactive ground is ground that undergoes a spontaneous exothermic reaction after it comes into contact with nitrates. This is commonly caused by inert rock hosting sulphide minerals, such as pyrites that act as the reagent. The presence and subsequent rate of reaction with nitrate based bulk explosives can be difficult to predict. Once identified, only explosives that are tested and proven to be compatible with the reactive ground may only be used. These typically take the form of inhibited ammonium nitrate emulsion blended with a limited volume of ANFO or porous prilled ammonium nitrate (PPAN) to ensure that all AN prills in the blend are wholly encapsulated and thus protected from the reactive ground. The requirement for high emulsion content bulk products limits the suite of products available for use to high energy, and high expense products. Further, if chemically sensitised products are used, charged holes must be left unstemmed to allow for gassing to occur, adding delay and exposing the blast crew to an unconfined charge in reactive ground. A range of inhibited products has been developed that are solid sensitised and can be bulked to as low as 0.9 g/cc (56.2 lb/ft3). The use of a solid sensitiser enables stemming to occur immediately after each hole is charged, confining any unplanned detonation more safely within the rock mass. The effective and precise manufacture of bulked inhibited products required a new and innovative Mobile Processing Unit (MPU) design. This MPU required the ability to blend two solid raw materials (AN prill & sensitiser) along with two liquid ingredients (AN emulsion and process fuel). This MPU has been designed, manufactured and has used successfully to manufacture low density inhibited explosives. This paper presents an innovative shift in inhibited bulk products with specific reference to their manufacture and application.

By R H. Stevenson

This paper deals with a new variation of the cast blasting technique, where-in the object is to cast the economic deposit out front under the overburden, while avoiding dilution from the floor material. To date, the technique has been successfully applied at two cement quarries in Iowa and at a granite quarry in Minnesota.

Jan 1, 1991

By U. Steiner

Electronic detonators have been in commercial use for a decade, with an excellent safety record. This paper lists known incidents involving electronic detonators. Typical standards required by regulatory bodies for static electricity and electromagnetic fields are reviewed. The performance of some detonators is compared to these standards; in general the minimum standards are easily exceeded. The general resistance of electronic detonators to extraneous electrical energy that can be derived from the body of test results is compared to danger levels for exposure of humans to these energies; it is shown that electronic detonators can safely tolerate higher electrical energies than people can. This comparison includes comparable data for electric detonators, which are shown to be more vulnerable to extraneous electrical energy than people are. Electronic detonators also bring significant safety benefits in blasting due to their testability, two-way communications, reliability, programmability and precision. The links between these attributes and enhanced safety are discussed with examples from actual blasting. Although electronic detonators are usually more vulnerable to extraneous electricity than non-electric initiation systems, the paper shows that the net safety benefit in handling and blasting is in favor of electronic detonators, which are the safest initiation system that has ever been offered to the mining industry.

Jan 1, 2010

By Thierry Bernard

It was in the 1980s that USBM published one of the first regulations to protect constructions from the effects of vibrations caused by mine blasts. Several countries have made their own regulations or recommendations since then with vibration limits that are often lower. However, on many sites, operators choose vibration limits that are lower than those of the existing standards, in order to limit the number of complaints received. The real question is how can we know what level of vibration is susceptible to create or worsen an existing crack in a construction. MCM, to the north of Quebec, is working a deposit on the periphery of the town of Malartic. Within the scope of its environmental monitoring programme, together with the joint monitoring committee, MCM has equipped four sample houses for over 18 months, in order to learn if there is a relationship between the evolution of damage to existing constructions and the seismic levels of vibrations created by mine blasts. The publication presents the results of this unique study that has analyzed millions of measurements (seismic, extensometric, and temperature) to define what relationship exists between the levels of vibration and the movement of cracks. Some surprising results versus some published previously (see ref) might change our perception of the subject.

Jan 1, 2018

By Aiden Carey, Jim Kennedy

During December 2007, Lake Cowal Gold Mine located in New South Wales, Australia experienced a significant pit wall failure. The wall failure resulted in the deposition of a large quantity of saprolite consisting largely of clays and lake bed sediments to the bottom of the Phase 1 open pit mine. This wall failure ultimately buried two loaded blast patterns.

Jan 1, 2011

By Paulo Couceiro

Highly non-ideal explosives usually tend to react expressively below their ideal detonation velocities. In these cases, dimensional effects and product heterogeneities become important to proper model the detonation state. Although Direct Numerical Simulation (DNS) techniques can provide a complete and exact solution for this problem, its actual computation cost is still not practical for industrial applications. In order to minimize these constrains, a simplified two-dimensional steady non-ideal detonation model for cylindrical stick explosives is developed. Based on an ellipsoidal shock shape approach, the proposed model uses the quasi-one dimensional theory for the axial flow solution and combine the post-shock sonic flow criteria with some limiting conditions for the explosives’ unconfined radius determination. Due to its attractive fitting capability for unconfined detonation experimental data, the model offers the possibility to predict the non-ideal detonation state for any diameter, resulting in a full mapping of the diameter-effect curve of the explosive. Thus, the proposed engineering approach is used to model the main properties of some of the most common ammonium nitrate-based explosives used in mining and quarrying industries, including the complete axial flow solution.

By Debra Satkowiak, Ronald Thomas

The Institute of Makers of Explosives (IME), a non-profit safety and security organization founded in 1913, is known for its industry best practices, Safety Library Publications (SLP), some of which have been incorporated into rules by regulatory agencies. The IME developed the first commercial storage, quantity distance (Q/D) table titled “The American Table of Distances” (ATD). It was developed by IME’s legacy association in 1910 and was originally based on observations of structural damage from 117 accidental explosions involving small to very large amounts of explosives, primarily dynamite and black powder. In 1930, the IME published a book, compiled by Ralph Assheton, called the “History of Explosions on Which the American Table of Distances was Based”. The distance in feet in the ATD were founded on the measurements at which inhabited buildings sustained substantial structural damage from the accidental detonation of explosives. For example, minor damage such as window glass breakage and the “shaking down” of plaster was not considered substantial structural damage. Other damage to property that was readily repairable was also not considered “substantial.” It was concluded that unless some integral portion of the building was damaged, the occupants would not be subjected to serious risks.

Jan 1, 2017

By Paulo Couceiro

Highly non-ideal explosives usually tend to react expressively below their ideal detonation velocities. In these cases, dimensional effects and product heterogeneities become important to proper model the detonation state. Although Direct Numerical Simulation (DNS) techniques can provide a complete and exact solution for this problem, its actual computation cost is still not practical for industrial applications. In order to minimize these constrains, a simplified two-dimensional steady non-ideal detonation model for cylindrical stick explosives is developed.

Feb 1, 2020

By Christopher Laughton

A new underground laboratory is under construction at the recently closed Homestake Gold Mine, Lead South Dakota, United States of America. The Deep Underground Science and Engineering Laboratory is designed to meet the needs of an international group of scientists and engineers interested in conducting fundamental and applied research at depth in the Earth’s crust.

Jan 1, 2011

By Uli Leiste

Two papers are presented which examine Air Deck Blasting, one from a computational aspect and the other from a shock aspect.

Jan 1, 2016