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By Tom Treleaven

This guide presents numerous patterns that provide 8 millisecond separations between initiated charges. The guide is tabulated in seven sections to provide quick reference by number of decks or bunch blasting. The pattern is presented in the section where the highest number of decks works. It should be noted that patterns applicable to multiple deck shootings are also applicable for fewer decks.

Jan 1, 1997

By Ali Kahriman, Abdulkadir Karadogan, Alper Celtikci, Ahmet Varol, Ertugrul Kaya, Turgay Ozat

This paper presents analysis of environmental effects induced by cautious blasting during the construction of the Istanbul Subway 4 Levent - Ayazaga Darulsafaka Metro Tunnel Project carried out by the contractor, located at Northern Istanbul in Turkey. Within the scope of the study, for the prediction of the peak particle velocity and to determine the slope of the attenuation curves together with the maximum charge per delay for the S6-7-8 shafts of this tunnel route, ground vibration components were measured carefully by using five vibration monitors during the construction of the tunnels which required blasting. The particle velocities and frequency values of all blast events are evaluated according to the United States Bureau of Mines (USBM) and German DIN 4150 Norms in order to predict, and compare the influence grades to the neighboring buildings, and structures. Also, data pairs of scaled distance and peak particle velocity obtained from 107 records belong to 51 shots were analyzed statistically. Empirical relationships with correlation at the 95 % confidence interval were established for these tunnel excavations and suggested for the test sites in order to estimate particle velocity of the ground vibrations. As a result of the studies, some practical charts are created in order to minimize the psychological effects of the shots, and simplify the authorities of shots’ job. And last but not least, make sure that the shots will be done in a controlled way.

Jan 1, 2011

By Jose Luis Pineda Villarreal

New technologies emerge every day with practical applications for open pit mining. For every operation, managers need to understand the best way to increase efficiency in drilling, blasting, fragmentation and hauling routes.

Jan 1, 2018

By D. Rudenko, C. T. Aimone-Martin, J. K. Ratliff, I. G. Wong, J. Aiken, R. E. Burnham, T. A. Davidsavor

A small quarry blast was conducted with a maximum of 90 pounds per delay and shortly afterwards, area residents sensed ground motion and building shaking indicative of an earthquake. In addition, seismometers up to 500 miles (800 km) away recorded a magnitude 2.8 earthquake located in the area. Positioned in a seismically inactive area, southern Minnesota is not known for earthquakes. The earthquake was originally described by the USGS to be a surface blast at the quarry. Analysis showed that the earthquake occurred shortly (approximately seven seconds) after the quarry blast some distance away and well below the surface. This paper describes the evaluation of the “seismic events” including the blast, the following earthquake, initial governmental response, and provides the framework for assessing the relationship between the blast and the earthquake. The paper also discusses management of large volume claims from a complex event and presents a claims management strategy with best practices.

Feb 6, 2023

By Rachel E. Gooding, George C. Emmett, David R. Bradley

The United States (U.S.) Department of Homeland Security (DHS) Directorate of Science and Technology (S&T) is using a probabilistic risk assessment (PRA) approach to evaluate the risks from terrorist use of explosive materials against the Homeland. A similar approach is currently being used to evaluate the risk from terrorist use of chemical, biological, radiological and nuclear materials.

Jan 1, 2017

By Julijan Bratun, Joze Kortnik

Production of technical stone is an important economic branch in Slovenia. In 2009, we had 95 dolomite quarries, 27 limestone and 6 silicates quarries, according to the Ministry of Economic Affairs. Together they produced nearly 15 million tons of aggregates. The production in quarries is mostly performed with drilling and blasting method and only a minor part with other method like mechanical mining method.

Jan 1, 2011

By Jason Baird, Joshua Hoffman, Phillip Mulligan

The purpose of this report is to address the method of reducing the overall explosive weight of Explosively Formed Projectiles (EFPs) while still achieving satisfactory performance. This reduction is crucial in order to comply with outdoor explosives testing standards for Missouri University of Science and Technology’s (Missouri S&T’s) Experimental Mine. Initial EFP design testing exceeded given limitations, making reliable data difficult to ascertain. EFPs must be tested outdoors to allow for specific information recordings which aid in defending against them.

Jan 1, 2010

By F Ouchterlony

Soviet precursors to Cunningham’s Kuz-Ram model from 1983 are described. They are rooted in the mean fragment size and Rosin-Rammler (RR) fits to sieving data and rely on approximations. Three versions of Kuz-Ram model are presented and all three are de facto based on the median fragment size x50, even if the term mean is used in the papers. This discrepancy caused Spathis in 2004 to suggest a correction procedure for the Kuz-Ram rock factor A, which was said to explain some of the missing fines in the model. This correction, while applicable to Cunningham’s 1983 paper, does not apply to his 1987 paper in which he presents his own A factor. Common fixes of the Kuz-Ram model’s fines issue are fragmentation models where the fines are mainly generated in a crushed zone around a blast hole. This is contradicted by careful model blasting tests. The lack of a largest block size in the RR function may lead to spurious values of the uniformity coefficient n, e.g. in conjunction with image based fragmentation measurements or crusher modeling. These issues may be solved by using the transformed RR function, which has a largest block size xmax or its replacement by the Swebrec function such as in the KCO model.

Jan 1, 2016

By David Leidel

A revolution in hydrocarbon well completions within the last thirty years has enabled drillers to tap the resources of known gas plays in an economically viable manner and deliver to market natural gas supplies for industrial, transportation and domestic use without the importation of liquefied natural gas from verseas. An added benefit has been the convenient location of one of these gas plays, the Marcellus Shale, in the Northeastern states strategically close to a major natural gas market, namely the cities and towns of the New England and Mid-Atlantic states. As a sidelight, the development of the tight gas reservoirs and their subsequent production has created thousands of jobs in an otherwise lackluster economy.

Jan 1, 2014

By Catherine T. Aimone-Martin, Kristen Kolden

In August of 2013 the USDA Forest Service (USFS) blasted bedrock at the base of a waterfall in Kanalku Creek within the Kootznoowoo Wilderness Area on Admiralty Island in the Tongass National Forest located in Southeast Alaska. The purpose of the blasting was to widen and deepen a plunge pool at the base of a waterfall complex considered to be a partial barrier to migrating sockeye salmon. Drilling and blasting to remove 12 to 15 cubic yards of rock occurred over a two day period.

Jan 1, 2015

By C. Adcock, R. Farnfield, G. Adderley

The use of explosives to create special effects in the film industry is a well-known past time. A recent production required simulation of a large scale water splash from the effect of a statue falling from a cliff edge and impacting on an open body of water. This was to be achieved through the use of precisely delayed explosions detonated near the surface of the water. A survey of the area revealed a breeding farm for sea bass approximately 250 metres (273 yards) from the intended blast area. It was initially thought that the water pressures produced for the detonation of the explosives may cause harm to the fish. Much work has been carried out over the past few decades on the effect of open water blasting and its effects on aquatic wildlife; this includes water pressure modelling techniques which can be used as predictive tools.

Jan 1, 2010

By Hector O. Romero, Paulo C. Fernández A, Claudio C. Gajardo

Phase 06 of the Los Bronces mine, currently under extraction for development, has the particularity of being close to the installations and buildings of a neighboring copper mine. Therefore, the blasts must ensure the continuity of the operation without affecting the nearby structures of the neighboring district, which include Maintenance sheds and Warehouse. Specifically, the safeguards consider a scenario that includes: - Flyrock projections (<150m) - Edge profile studies - Vibrations according to the NCh3577 standard - Nitrous gases Additionally, Phase 06 is also within Los Bronces, so strict control over spillage into the pit is necessary to avoid blocking ramp access to this level. The challenge lies in protecting not only the operation and facilities of the neighboring mining district but also the operability of Los Bronces. Thus, addressing these considerations, blasting configurations are developed with prior simulation of vibration models, flyrock, and spillage in all blasts, with strict control of technical design and implementation to ensure the results. Currently, blasts are successfully executed with control of projections based on the proximity of the projects, vibration (<40mm/s) with decoupling of holes of 17 mm/s between holes, reactive rock tests for explosive selection (loading advancement), and spillage simulation inside the pit according to the loading design; thus, ensuring operational continuity and mine development.

Jan 21, 2025

By G. C. Naveen

Punatsangchu Hydroelectric Project Authority is constructing 1020 MW underground hydroelectric project in Bhutan. The project envisages construction of concrete dam, Desilting Chamber, Head Race Tunnel, Power House Complex and Tail Race Tunnel. Tunneling is one of the major activity in any underground projects as they are driven for multiple activities. By and large the tunnels are a major part of connecting networks from surface to caverns/underground working sites. Many tunnels in hydropower project are part of water conducting systems and one such important tunnel is the Tail Race Tunnel in this project and had to be excavated in thinly foliated rockmass conditions by D&B method. The rockmass is traversed by three to four joint sets and few minor shear seams. Rock Class “Q” values were between III and IV. Tunnel was excavated by full face parallel hole drilling blasting method. The adopted blasting method consisted of drilling 45mm (1.77 inch) diameter holes to a depth of 2m and the drilled holes were charged with 40mm (1.57 inch) diameter cartridge explosives and charges were initiated with half second non electric initiators. The perimeter holes were drilled at closer spacing of 30cm (1 feet) and alternate holes were charged using 32mm (1.23 inch) diameter cartridges explosive. Low dipping foliation joints present in the rockmass tend to slab in crown portion and erratic occurrence of intrusive bodies lead to unpredictable behavior of rock mass posing a major challenge for the safe excavation. Stability was a major issue through controlled blasting under constant supervision too could not limit the overbreak in certain weak rockmass conditions thereby exposing cavities of about 2.5m (8.2 feet). The stabilization of these cavities and handling the overbreak due to rockmass condition was time consuming and warranted additional supports. With systematic measurements and controlled blast designs the Horse Shoe Shaped Tail Race Tunnel of 9.1 m (29.85 feet) diameter and 304m (997.37 feet) length to connect with Downstream Surge Gallery of 314m (1030 feet) length, 18m (59 feet) wide and 58.8m (193 feet) height in thinly foliated and jointed biotite gneiss rockmass was successfully excavated.

By Kush Patel

This paper presents methods currently available for the evaluation of bulk explosives and discusses the results of the evaluation of bulk explosives using each of the methods. Through the preliminary experimental analysis, wet chemistry and the Bulk Explosive Analyser were found as methods most suitable for the evaluation of bulk explosives. This paper also presents data obtained from the experimental comparison of the wet chemistry method and the Bulk Explosive Analyser.

Feb 1, 2020

By Robert Hopler

After the disbanding of the Gunpowder Trust Association in 1904, the Association of Independent Powder and Dynamite Manufacturers was formed, followed in May of 1906 by the formation of the Association of Manufacturers of Powder and High Explosives. Due to a lack of success in attracting all manufacturers to membership, these organizations did not survive.

Jan 1, 2014

By Brian Stump, Rong-Mao Zhou

A series of single-fired (simultaneously detonated) explosions were conducted in an Arizona copper mine. The explosions spanned yields from 1700 to 13600 lbs (773 to 6169 kg) and were all detonated in an approximate 100 m by 100 m area. In order to quantify the effect of the mine free-face, the individual explosions were also detonated under three different emplacement conditions including at the free-face of the mine under normal burden, twice normal burden and fully contained. The purposes of these experiments were to investigate: (1) Generation of in-mine and regional phases such as Pg, Pn, and Lg from mining explosions; (2) Quantification of the relationship between yield and seismic amplitudes; (3) Quantification of the effect of confinement; and (4) Similarities and differences between single-fired waveforms and those from delay-fired explosions. Instrumentation was deployed at near-source (100-700 m) and in mine (1-5km) distances. Empirical scaling relations for the different shots in this test series were developed in order to quantify the effects of yield and confinement.

Jan 1, 2006

By Steve Dillingham

PHYSICAL BLAST DATA Pattern Description All measurements related to the description of the physical blast pattern must be made with the mind-set that it has to tell a powerful factual story enabling a future accurate reconstruction of the event. A case has never been lost because too much factual information was available to assist investigators. An accurate physical description of the pattern must be provided based on the blaster’s observations of the pattern actually loaded. The blaster must measure the pattern size, depth, face heights, etc., recording only accurate results. All too often, a blaster records simple pattern sizes and information relayed to him or her from the driller, or from a phone call into the office the night before for powder pre-load inventory purposes. If a pattern was actually measured on the job site by the blaster to be 8.5 x 9.5’, it may, in fact, originally have been ordered at 9’x9’, 8’x9’, or 9’x l0’. In a claim situation, particularly flyrock, recording a “generalization” of what was loaded could result in an interpretation of a blaster’s negligence due to “not knowing or caring” what the actual pattern was, and not loading appropriately for conditions. It is important to remember that other documentation exists such as a drill log from a contract driller or mine records that may provide a different interpretation of the loaded pattern.

Jan 1, 2002

By Tapan Goswami, Stephen Jeric, Geoff Brent

Highwall failures in large deep open cut mines have very significant safety and commercial implications. There are many factors influencing the stability of highwalls. The major influence is the interaction of the local geology with the shape of the pit wall. This factor is in the realm of the geotechnical engineer and is beyond the control of the blasting engineer. However, a secondary influence is the blastinduced damage to the wall. In most open cut metal mines the blasting strategy to control this damage involves the use of separate production and trim blasts bounded by presplits at the final wall.

Jan 1, 2011

By E Novikov, D Johansson, U Nyberg, A Beyglou, N Petropoulos

Fragmentation is an important factor for improving downstream processes in mine operations. Six trials have been conducted at the Aitik copper mine to investigate the effect of ultra-short inter-hole delay times, i.e. smaller than 1 ms/m of burden, on fragmentation. Swelling, MWD data, and crusher efficiency were also evaluated for trials. According to the results, the effect of examined short inter-hole delay times, i.e. 0.14 to 0.86 ms/m of burden, on fragmentation was found to be marginal. Delay time of 0.43 ms/m of burden resulted in slightly finer fragmentation and larger swell; however, the effect of short delays was overshadowed by the effect of small variations in specific charge.

Jan 1, 2014

By D. Lansburg

Electronic detonators are increasingly being used in today’s blasting in quarries, seismic, surface and underground mines. Electronic detonators offer several distinctive features over electric and non-el (shock tube) detonators including better timing accuracy resulting in excellent fragmentation and vibration control, field programmability and digital safety means. Because of the prerequisite electrical communications between the electronic detonators and the blasting machine, the layout or hook-up of these detonators can play an important role in obtaining the communication fidelity.

Jan 1, 2011