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By Norman Paley, Zachary Pickett

The Red Dog Mine is a high-grade zinc-lead mine located in northwest Alaska which began operations in November 1989. In June 2014 the upper half of a charge in a trim shot in the Aqqaluk pit deflagrated. No other holes in the area were observed to react and the remainder of the pattern was shot without incident. This was the only known case of a deflagration in the 25 years of operations. As part of the investigation into the cause of this incident rock samples were obtained from the area of this hole and from other areas in this pit.

Feb 1, 2020

By Matthew Hirsch, Jason Connot, Nathan Rouse, Srivatsan Jayaraman, Akash Adhikari, Brent Meins, Purushotham Tukkaraja

The Deep Underground Neutrino Experiment (DUNE) is a world-class particle physics research project currently being constructed 4,850 ft, 1,478 m underground at the Sanford Underground Research Facility (SURF), former site of the historic Homestake Gold Mine in Lead, SD. Construction for the project involves drill and blast excavation of 800,000 tons of rock to house neutrino detecting cryostats adjacent to on-going particle research and sensitive lab areas. To protect nearby labs during the planned 4 years of blasting operations, project specs required installation of six steel, heavily reinforced blast doors designed to withstand 20 psi blast loads. This research aimed to quantify the pressure reduction across the blast doors and more accurately model underground blast wave propagation. 827 blasts to date have been monitored at eight locations on the 4850 level of SURF with some locations behind blast doors and some in front. Additionally, pressure measurements directly in front of and behind one blast door were taken during 94 blasts.

Feb 6, 2023

By Lifent Li, Jhon Silva-Castro

Since millisecond-delay detonators were first introduced, at least two variables, among others, have been more closely considered when timing a mining blast: the accuracy and the precision of the initiation system. Currently, most mine blast design software has the capability to use the precision/accuracy of the firing system and display the overlap timing window between charges in any given time interval (8 ms, 3 ms, etc.). Despite these technological advances, there are still situations which result in the overlapping of charge timings. The consequences of overlapping charges involve flyrock events, fragmentation and diggability problems, and other inconvenient situations affecting the operation of the mine.

Jan 1, 2015

By Ankit Jha, RICHARD AMOAKO

In this paper, we examine the challenges associated with the use of empirical rock fragmentation models. We highlight key parameters omitted by these models, and propose a machine learning approach that incorporates these parameters, leading to a simple, yet more accurate approach to blast design.

Feb 1, 2020

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 Alejandro Ferrada Vergara, María Jesús Barros Godoy

Reducing costs while maintaining productivity and achieving good results is a constant challenge in mining operations, especially in the drilling and blasting stage, since a bad blast can affect production plans, increase costs, affect safety and jeopardizing the pit stability. Examples of undesirable blasting effects are: flyrocks, boulders, loading equipment damages, lower production rates, etc. In some of the biggest open pit mines using conventional blasting patterns visited by the authors, the pattern does not adjust properly to the rock mass, in most cases blasting polygons are large and the rock mass condition is variable within the designed blasting pattern. On the other hand, conventional blasting patterns with stemming columns use 40-50% of the blast hole with inert material (the stemming). Moreover, blasting engineers spend efforts to improve fragmentation results by increasing explosive charge in spite of having the negative effect of ground vibrations, with little or no success. The classic approach is "the more explosive in, the better the fragmentation is", furthermore it is assumed this relation is direct and infinite, but it is definitely wrong. This work challenges the notion of a limitless direct relationship between explosive charge and fragmentation, this means this is partially true but just up to a certain limit. In other words, there is still room to improve energy distribution among the classical blasting techniques without increasing the explosive energy by using air decks. In the work to be presented air decks are built using conical shaped stemming plugs called Paraplug®. The results obtained suggests a wedge effect acts in the bottom of the stemming column that cushions the shock wave and the air deck to reduce the detonation pressure (this is due to the decoupling factor resulted from the air deck). The demonstration shows improvements in fragmentation results, reduced vibration records accompanied with lower dust column and costs savings in explosive charge.

Jan 21, 2025

By Harry Thompson

In using explosives to blast stumps from the ground in order to prepare it for farming, it is comparatively easy to place the charge under a stump having a semitaproot or a lateral system of rooting by boring or digging a hole in the earth to a point under the center of resistance and deep enough to give the desired effect.1

Jan 1, 2015

By R. Hazael, R. Alford, R. Critchley

The ability to compare explosives is fundamental. Numerous methods are used and while simple conversion factors are often used, the use of TNT Equivalency (TNTe) is not a simple subject as explosives exhibit very different equivalencies depending on whether the pressure or impulse are being considered as well as other conditions. The scaled distance has been found to have a significant effect on the TNTe but due to the difficulty of taking measurements at very close ranges, no TNTe have been quoted for charges in direct contact (Z=0). This paper describes the use of a ballistic pendulum to measure the impulse from contact charges and presents some surprising results that require a two-stage propulsion, as originally described by Backofen, to be explained.

Jan 1, 2024

By Andrew F. McKown, Robert A. McClure

This paper will describe a trench blasting case history in close proximity to several adjacent structures, including a bridge abutment, railroad tracks, and utility pipes. Some design considerations involved in close-in blasting will be discussed, including allowable peak particle velocities and prevention of rock block movement. The importance of several trench blast round design factors is pointed out, including choice of explo sive to prevent propagation, maintaining a sufficiently high powder factor, and mucking out for maximum relief after every round. Vibration monitoring and good record keeping are shown to be important in order to evaluate blast problems and make modifications to round designs.

Jan 1, 1988

By Keith Best

It has been said that when a person does something right no one remembers but when they do something wrong no one forgets. This statement, when applied to the explosives industry, has never been truer. Think about it.How many times have you seen a news crew reporting on how well a blaster is doing his/her job? Normally, all you will see is how bad things are going and how much “damage” is being done.

Jan 1, 2008

By Tristan Worsey, Brad Gyngell, Todd Buschjost, Gus Diehr

This paper highlights the opportunities provided by integrating MWD data and drone generated 3D model to industries that use explosive energy to perform useful work as an integral part of their rock extraction process.

Feb 1, 2020

By Joshua Hoffman, Braden Lusk, David McLane, John Rathbun

The dynamics of explosive detonations are understood; however recreating a real-world, to-scale scenario is costly. The use of a shock-tunnel allows testing to be done on a smaller scale, with the simulated effect of a large explosion. Analyzing explosive waveforms using this method can greatly reduce cost in testing blast-resistant products, such as anti-terrorism devices, mine safety products, and military equipment. The purpose of this project is to better the understanding of how the waveform dynamics of an explosive detonated within a shock-tunnel differ from those in an open-air arena test.

Jan 1, 2011

By George W. MacDonald

ALFRED NOBEL was born at Stockholm on October 21st. 1833, and died on December 10th, 1896. Although Sobrero’s discovery of nitroglycerin dated back to 1847, this explosive was manufactured on a commercial scale for the first time in 1862, by Nobel at a factory which he erected at Heleneborg, near Stockholm. These works were entirely wrecked by an explosion in 1864. In 1865, he erected works, which are still in existence, at Winterviken, near Stockholm. In 1864 Nobel introduced modifications in the manufacture of nitroglycerin which were the subject of a patent (see footnote No. 1), and at the same time, claimed a process for the detonation of nitroglycerin. Nobel states that, up to that time, the method used for the manufacture of nitroglycerin consisted in pouring glycerin, drop by drop, into a mixture of sulphuric acid and nitric acid contained in a refrigerating mixture. In order that the nitroglycerin should not be decomposed, the temperature was not allowed to rise above 0° C.

Jan 1, 2012

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 Jeffrey Meissner, Charles Dowding

Cracking is one of the concerns cited by owners of structures adjacent to construction or mine blasting. During the past decade a large number of measurements have documented the low level of crack response produced by typical, ground motions compared to those produced by climatological effects. These data support the observation that there is a level below which ground motions do not cause even cosmetic cracking. As with all new findings, these crack response measurements need to be thoroughly investigated for all possible alternative interpretations. Among these alternatives is that uncracked locations are more affected than cracked locations. This paper presents measurements to shed light on the influence of existing cracks and the response of uncracked, but weak locations. Blast and weather induced responses of cracked and uncracked areas of gypsum wall board are compared in two structures: one near a surface coal mine in Indiana, the other near a limestone quarry in Florida. The ground motions that excited one of the structures were unusual in that the dominant excitation frequencies of 5 Hz were near the structure’s natural frequency and amplitudes exceeded 0.7 ips (18mm/s).

Jan 1, 2011

By Terri Jordan, Gregory Hempen, Thomas Keevin

Water-borne blast pressures from confined blasts were recorded as part of a submerged blasting program in Florida for channel deepening. The blasting was confined within the rock floor by stemming. Shot patterns of stemmed borings were recorded, as were two open-water shots. One hole of one shot was not confined properly, which allowed comparison of confined and a poorly confined larger charge weights per delay. The pressure data were intended to gain information on typical pressure measures from the rock removal program relative to impacts on marine organisms. Water-borne pressures from actual confined, rock-removal shots validate the hypothesis of lessened impacts to aquatic and marine biota.

Jan 1, 2007

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 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 Jarrod Bonsmann, Zachary T. Plitt

"A surge in mine related deaths in Middle Eastern conflicts over the past few years has prompted research into the mitigation of the impact on a blast loaded vehicle. In past military conflicts, it has been observed that blast loading can cause injury to the brain but the exact cause is unknown [1]. The recent rise in deaths due to Improvised Explosive Devices (IEDs) has led to research that has speculated that the high acceleration experienced by soldiers on a blast loaded vehicle leads to Traumatic Brain Injury (TBI) [2]. This research aims to investigate vehicle designs that can reducethe peak acceleration for passengers on board the vehicle, in the event that the vehicle is blast loaded by an IED."

Jan 1, 2016

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