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By Sandy Tavelli, Thomas L. Barkley

This discussion will present a case study in developing solutions to a metropolitan quarry’s public relations, legal, environmental, and productivity problems. It details an extensive and detailed project to address the blasting practice in a medium sized quarry that is surrounded by residential and industrial zones. The principle work was done over a four-month duration during the normal production season. It included detailed drilling and blasting audits for baseline information. In addition, geologic characterization, seismic modeling, correction of deviations from best practices, and implementation and monitoring of precise electronic timing to provide dramatic solutions for the quarry. The quarry is in the near suburbs of a large metropolitan city. It is framed on two sides by residential municipalities and on two sides by industrial zones. At the start of the project, the quarry was in court as a result of the lawsuit by one of the neighboring towns that was suing to close the quarry. The lawsuit had progressed to the advanced stage where in the Judge had appointed an arbitrator to make the decision of continued operation. This arbitrator was to observe our progress and recommend to the Judge the disposition of the case.

Jan 1, 2004

By Robert Hopler

Blasting powder is a slow-acting, black, granular explosive made of sulphur, charcoal and either potassium nitrate (saltpetre) or sodium nitrate. The blasting powder containing potassium nitrate is known as “A” blasting powder; that containing sodium nitrate, as “B” blasting powder. “A” blasting powder is a little denser, a little stronger and a little less hygroscopic than “B” blasting powder.

Jan 1, 2014

Blastserve, ISEE’s Listserve is being replaced by our new Blasters Forum-online, an exclusive member benefit. Our goal is to provide an ISEE forum for you to network with your peers and exchange technical information and get answers to your technical questions. This forum is unique in the fact that only ISEE members are permitted to review or post on the site. Over time you will be able review the discussion history and use the archived discussion as a valuable resource for trends in the industry. The following are a sample of the discussions that too place recently on Blastserve

Jan 1, 2013

By D. Fry, S. Hunsaker

Ammonium nitrate in explosives and sulfides in reactive ground have the potential to react at ambient and elevated temperatures resulting in premature detonations. The Australasian Explosives Industry Safety Group (AEISG) published, in 2006, a Code of Practice1 for elevated temperature and reactive ground. This paper reviews the chemistry, general reactivity of various ground types, elevated temperature hazards, and testing protocols contained in the code, that are industry best practices for managing ammonium nitrate-based explosives in elevated temperature and reactive ground conditions. In addition to reviewing the 5th edition AEISG Code of Practice, data is presented validating the recommended sampling guidelines within the code. Dyno Nobel has been screening reactive ground samples and performing sleep time testing since the code of practice was first released. Test results demonstrate the effects of samples that are allowed to oxidize before testing and are shown to be subsequently less reactive and not representative of the actual hazards facing mining blasting operations. Results also show that for a given reactive ground sample, reaction times decrease with increasing temperature. Data also quantify the delay in reaction time given by inhibited products. These results emphasize the importance of proper sampling and preparation of samples to accurately characterize elevated temperature and reactive ground hazards. They also demonstrate the efficacy of inhibited products in managing these hazards

Jan 1, 2024

By Jerome H. Stofleth

In June of 1998, the DeBruce Grain Elevator was devastated by an accidental explosion caused by the unintentional ignition of grain dust. The DeBruce grain elevator was the largest ‘single head-house’ grain elevator in the nation. It was comprised of 450 cylindrical grain silos, 30 feet in diameter by 120 feet tall, with a centrally located headhouse. Immediately after the explosion, rescue operations were started for seven missing workers. The Federal Emergency Management Agency (FEMA) had taken over operations of the site by day two. On day three FEMA contacted the Washington DC office of the Department of Energy for explosive expertise, who in turn contacted explosives experts at Sandia National Laboratories (SNL) and Los Alamos National Laboratories (LANL). FEMA was looking for guidance in making the decision to downgrade their operation from a rescue to a recovery operation. Based on some chemical equilibrium calculations, and basic explosive engineering techniques, the SNL/LANL team was able to provide the necessary input to allow the decision to be made for the operational downgrade. At this point, only one worker remained un-recovered.

Jan 1, 2004

By J Lyall Workman, Peter N. Calder

Large hole rotary drilling is one of the most common methods of producing blastholes in open pit mining. Large hole drilling generally refers to diameters from 9 to 17 inch (229 to 432 mm), however a considerable amount of rotary drilling is done in diameters from 6½ to 9 inch (165 to 229 mm). These smaller diameters are especially prevalent in gold mining and quarrying.

Jan 1, 1996

By Alexander S. Escalante, Luis R. Ramirez, Nelson A. Arostegui

Research, analyze, discuss, design, and build an electric oven to perform one of the quality control tests the fanel or common fulminers to determine what temperatures they can detonate at. Give practical applications, conclusions, recommendations and bibliography.

Feb 1, 2020

By Thomas P. Dowling

Since the 1950's, blasting practices have undergone many revolutionary changes. Some of the more radical departures have involved, in addition to high speed drilling equipment, a myriad of new explosives, blasting agents, boosters, initiators, initiating systems and delay devices. The introduction of ANFO in the mid 1950's as a blasting agent seems to have instigated a trend toward the development and use of less sensitive blasting agents. The evolution of slurries or water gels has produced dense, high strength, water resistant products which has further promoted this trend away from the more sensitive, conventional explosives.

Jan 1, 1975

By W. Boas, R. Silva, D. Yumi, L. Steffen

The continuity of the flow and stages within the mining process is essential to achieve success in its operation and results, especially when it comes to a gold mine. During the first seven months of 2022, crushing at the Morro do Ouro Mine had 19 stops in the primary crusher due to equipment blockage/obstruction, this could be due to the size of the material that was blasted with explosives and fed. The feeding of coarse material to the crushing plant impacts the operation in several ways, for example, premature wear of the equipment, reduction in the supply of the remainder of the beneficiation, reduction of the buffer pile and damage to the conveyed belt. In a mine located far from the community, the fragmentation improvement is mainly related to load increments or some other relatively simple change. However, when it comes to a mine located close to communities, alterations of this type must be analyzed in detail, as it can have an impact mainly in relation to vibration and flyrock. Aiming to improve the efficiency of the blasting, mainly in relation to the result of fragmentation, a project was created to improve the efficiency of the blasting with a focus on reducing the crushing stoppage and reducing the amount of material discarded due to inadequate granulometry. During the evolution of the project, several improvement solutions were proposed, for example adjustment of the power factor in relation to the geological characteristics of the rock mass, drainage, blasting geometry, vibration reduction techniques and several operational improvements. By using the techniques and methods identified as improvements during the project, it was possible to observe and quantify improvements in relation to the fragmentation of the blast. During the months of January to July 2022 there were 19 events. It was estimated that at this rate there would be 14 more blockage events, but there were only 3 events and that meant a 79% reduction in blockage. In addition to the reduction in crushing shutdown events, there was also a 53% reduction in the amount of ore that is discarded due to inadequate granulometry and, with that, the feed rate of the grinding system was able to reach the maximum feed limit due to the material being fed to the mill well fragmented, contributing to increase the production and productivity of the beneficiation process at the Morro do Ouro Mine in Paracatu-Minas Gerais-Brazil.

Jan 1, 2024

By Brian Hawkins, David Bradley, Rachel Gooding, Lucas Rodriguez, Patrick Wilson, Kevin Wegman, Dhruv Mittal

The Department of Homeland Security (DHS) has undertaken a probabilistic risk assessment (PRA) approach to quantifying the infrequent, yet high-impact explosive terrorist attacks on the United States (US) homeland and aiding in mitigating that risk through efforts ranging from intelligence gathering, defense postures, detection architectures, partnering with industry to prevent acquisition, and informed medical response. Based on an evaluation of existing model options, a path to the realization of an exterior explosive model (EEM) that builds upon existing models while meeting runtime requirements, maintains consistency with existing DHS chemical, biological, radiological, and nuclear (CBRN) consequence models, and provides sound estimates of the human health consequences of explosive terrorism attacks in open-air urban and rural environments.

Jan 1, 2018

By P A. Lang

Canada is constructing an Underground Research Laboratory as part of a comprehensive program to evaluate the concept of nuclear fuel waste disposal deep in stable rock formations. Careful blasting methods have been designed and quality control procedures have been used for the excavation of the access headings in the underground facilities. This paper describes the work done between 1984 December and 1986 December at the second level, 240 metres below surface.

Jan 1, 1987

By Ray Jambakhsh, John Okell, Frank Cook

"In early 1988, an experimental study was carried out at the Inco's McCreedy West Mine inLevack, Ontario. The objective was to develop blasting techniques which would allow themine to maintain production targets and reduce blast induced vibrations and overpressure.Due to its close proximity to the town of Levack (approximately 900 feet), particularconcern was expressed as to the vibration and overpressure resulting from the undergroundblasting operations."

Jan 1, 1993

By Paul Worsey, Gillian Worsey

Description of Project:The basic blasting class underground lab at the Missouri S&T experimental mine in Rolla, o., shows the students how to drill, set up, load, and shoot a shot underground. In this case the shot was part of a new ramp to a second level.

Jan 1, 2014

By Blair Jackson, Tjaart Louw

Martha Mine, owned by Newmont Mining, Australia appointed Macmahon Contractors (NZ) Ltd as the mining contractor to drill, blast, and crush and convey ore for processing, followed by construction of a tails dam facility from the waste material. The open pit is located 140km(90miles) south east of Auckland, New Zealand in the middle of the township of Waihi (the main street of the town with a population of 3,500 is 90m from the perimeter of the open pit mine). Mining must proceed at 325,000m3 (of which involves blasting approximately 11,000 holes per month, in order to ensure continued ore supply.

Jan 1, 2003

By Clara Godoy, Paulo Couceiro, Juan Navarro

The continuous automatization and digitalization of the different stages involved in any underground construction bring new possibilities to optimize the operation. One of the most important requirements for the development of these projects consist of a proper rock mass characterization for optimizing the stages of the drilling, blasting and support cycle. In the last few years the road to digitalization has gone through data science and big data, showing the importance of data gathered to describe the geological and geotechnical environment that surrounds the operations. Since rock characteristics have an important influence in the drilling response, the technological advances in the sensorization of drilling machinery such as the Measurement While Drilling system (MWD) allow to gather the necessary amount of information to be applied in data science processes to evaluate changes in the rock mass with higher resolution than conventional methods. In this paper, Machine Learning techniques have been used to combine data monitored from the drill rigwith scanner profiles of the excavated sections to develop an automatic geotechnical rock mass characterization model able to estimate potential zones of over- or under-break of the remaining rock mass in underground blasting. By comparison of scanner profiles of the excavated sections with the blasthole positions, an Excavated Mean Distance (EMD) between the contour blastholes and the excavated profile has been obtained, which may be considered as damage measure. Considering blasting factors as constant, the model combines the rotary, percussive, hydraulic flushing and the rate of advance of the drilling, and the confinement of the rock mass by depth, to detect zones with different rock properties. This provide an early information of the rock mass condition around the blastholes and the prediction of expected overbreak generated after blasting, being possible to design more efficient bastings, in which each borehole is filled with the right and necessary explosive charge. The analysis comprises data from 57 blasts (around 1700 contour blastholes) and more than 4000 excavated sections.

By J. Rafael Otaíza, Francisco Mardones

This work has addressed the problem of creating a predictive model of the maximum particle velocities in the rock mass (PPV). The model designed specifically can model the subsequent vibrations of blasting based on geometric parameters, explosive loading, and the blasting process itself. Models based on artificial intelligence (AI) algorithms can find useful non-linear patterns to solve classification, regression, clustering, among other problems. They are flexible mathematical transformations adaptable to various objectives and types of data. With their different levels of abstraction, they can find a function that relates the input variables to the sought-after response. These models have been successfully used in similar contexts (Prashanth, (2018)) and have achieved state-of-the-art results in the field (Lawal, (2021)). The main challenge is to adapt them to the context of Chilean mines, in addition to including the geometric information of the blasting and the heuristic to obtain the set of optimal parameters, it is proposed to follow the work of (Simonyan, (2013)) and obtain "saliency maps" adapting it to tabular variables. We implemented an Artificial Neural Network (ANN) with a large number of neurons in the hidden layers. Models based on neural networks can find useful non-linear patterns to solve classification, regression, clustering, among other problems. They are flexible mathematical transformations adaptable to various objectives and types of data. With their different levels of abstraction, they can find a function that relates the input variables to the sought-after response. The literature shows that, for the problem of rock type identification, basic neural networks perform well (Simonyan, (2013)), but lack uncertainty estimates. This is a data-driven model, and in this sense, the model training was carried out using data from multiple operations in the large copper mining industry in Chile. In these databases, data consistency and the balance of the various independent variables that have the greatest impact on the model were ensured. With the above, the optimal hyperparameters of the model were determined, obtaining a predictive R-squared of 0.94.

Jan 21, 2025

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

By Alastair Torrance, George Boucher, Roger Keller

An investigative blast programme has been carried out to provide information on the best blasting methods to excavate Chek Lap Kok island in Hong Kong for the new airport. The objectives of the programme included the assessment of a range of blast design parameters and their influence on fragmentation. This has been evaluated by physical assessment, photo digitising of the muckpile and computer predictions. In addition, a model to predict the three dimensional muckpile shape has been successfully calibrated.

Jan 1, 1992

By Ruilin Yang

The vector sum peak particle velocity (PPV) of blast vibrations describes the blast vibration intensity more completely than the PPV of a single component waveform. It is more logical to use a vector sum PPV as a vibration limit than using a single component PPV. In 1980 the USBM recommended the frequency related peak particle velocity criterion. So far this method has been only applied to single component waveforms, but not to the vector sum PPV since there is no method available to associate a frequency to the vector sum PPV. The present paper describes a method to define a principal frequency associated with vector sum PPV. The method is based on the weighted average of the principal (zero-crossing) frequencies of the three tri-axial components at the time of the PPV.

Jan 1, 2015

By Stanley L. Lippincott

A number of Federal and State agencies require formal training for blasters. Federal agencies often specify the need for initial training involving all job responsibilities as well as periodic refresher training to assure adherence to current operating procedures. failure to provide and document such training can result in substantial penalties.

Jan 1, 1995