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By John Petty, John Loviza

As a blaster, have you ever had that uneasy feeing in the pit of your stomach as a codes enforcement official drives onto your jobsite? Have you ever needed an ally in a court of law against an unjust damage claim? Have you ever wished for a better and more open relationship with the guys who wear the badges?

Jan 1, 1996

By Andrea Francioso, Roberto Folchi

In order to comply with the latest European Highway Standards, the highway Salerno - Reggio Calabria, in southern Italy, had do be widened and upgraded to reduce its vulnerability to earthquakes. Reinforced concrete viaducts, no longer needed for the new road, had to be demolished. Many bridges still to be used for the highway required refurbishment due to 50 years of wind, frost and salt corrosion. This re-furbishment and new construction had to be carried out simultaneously. To keep the highway open dur-ing the renewal process, all traffic was directed to one side of the road. Demolition was conducted ex-tremely close to operational roadways and viaducts, as close as only 2 cm (0.8 in). Care had to be taken to ensure that the stresses (vibration levels), resulting from the demolished pylons and decks hitting the ground, were below the no-damage thresholds for the nearby acceptors (structures receiving the vibra-tion stresses). These structures included bridges, houses and buried pipelines (water, oil and gas). In some cases, care also had to be taken to preserve the existing pylons supporting decks that were being demolished; since the same pylons were going to be used for the new viaducts (bridges). New continu-ous decks in weathering steel replaced the old reinforced concrete decks.

Jan 1, 2013

By Constanza Bujes, Mark Jones, Graham Crook, Yansan Jamyanbaatar, Sedat Esen

Tracking ore characteristics such as grade and hardness from its original position into the material handling and processing stages remains one of the key challenges in open pit mining of hard rock deposits. The most efficient technique for rock fragmentation and separation of ore from waste is blasting, which induces changes in the grade distribution by displacing the in-situ ore into a diggable muck pile. Material movement defines the post-blast grade distribution, which is key to optimising the value of the ore and accounting for ore loss and dilution. Techniques to directly measure the displacement in open pit mining have been implemented routinely and have provided calibration and validation data for blast models to build upon. The JK Value-Based Ore Control blast movement model (JKVBOC) is the latest development of a series of research studies into blast movement and ore control at the Sustainable Minerals Institute of the University of Queensland. The blast model discretises the bench into blocks, defines the initial velocity of each block based on the blast design, confinement and explosive properties, and simulates the displacement using a physics engine. Calibration and validation of the model has been performed in open pit hard rock mines in Australasia in diverse confinement conditions. This paper describes the calibration and validation of the blast movement model against direct measurements of blast movement and final muck pile shape for a case study where the displacement of multiple shots was modelled for an open pit mine, with an analysis of the implications for ore loss and dilution. A key finding in this study is the need for further integration of this technology into the existing systems for ore control, and the potential for applications in tracking ore characteristics other than grade into process control.

By T Duff

This paper describes results from small scale tests conducted to determine the distribution of pressure on target plates when subjected to loading due to the detonation of a buried mine in various media. The tests are conducted by using saturated sand, dry sand, and water as the loading media. Different stand-off distances are investigated. Kolsky bars and pressure sensors are used to determine the free-field pressure - time profile of the output of the charge at any location on the vehicle bottom. For verification of the pressure results at certain distances, the specific impulse measured by utilizing different size round plates are employed. In order to investigate the loading mechanisms, high speed cameras are applied. The small-scale test results can be scaled to full scale by using verified scaling laws.

Jan 1, 2014

By Hairong Zeng, Matthew Baumann, Shahram Tafazoli, Edmond Chow

Measurement of rock fragmentation has evolved from a completely subjective and manual process to a statistically objective and semi-automated process. However, ultimately, the vision is to achieve a statistically representative and fully-automated process. From the blast optimization perspective, it is critical to receive reliable rock fragmentation results quickly to incorporate into the planning of subsequent blasts. Since manual rock fragmentation measurement methods tend to be time consuming, a fully-automated method is the practical way to meet these requirements.

Jan 1, 2012

By John Vynne

BHP’s Navajo coal mine installed drill monitoring and high precision navigation systems on their three overburden drills during 2002 and 2003. Details of the DrillNav system hardware and reporting system will be discussed, as well as the significant benefits Navajo has achieved since the systems were installed. Navajo is not satisfied with the current results and plan additional upgrades to the systems. In addition, Navajo plan to integrate the data from their drill systems with data from other systems to achieve even greater increases in drill productivity and to reduce overall mining costs.

Jan 1, 2007

By Finn Ouchterlony, José A. Sanchidrián

"A model for fragmentation in bench blasting that originates from dimensional analysis of fragmentation in asteroid collisions is presented. Percentiles of the size distribution are obtained in the basic model as the product of a rock strength-to-explosive energy ratio, a bench shape factor, a scale factor or characteristic size and a percentage passing-related factor. The parameters of the model are fitted to 169 bench blasts in different sites and rock types, bench geometries and delay times, for which thefragmentation of the muckpile was obtained by sieving. The basic model is found to significantlyimprove with an additional factor describing the rock mass structure in terms of the spacing and orientation of discontinuities, and another one describing the delay between successive contiguous shots; the latter is conveniently formulated as a function of the P-wave velocity and the holes spacing. The rock strength property chosen is the strain energy at rupture that, together with the explosive energy density in the rock (or energy powder factor), forms a combined rock strength/explosive energy nondimensionalfactor. The model, called xP-frag, is applicable from 5 to 100 percentile fragment sizes, with all parameters determined from the fits significant to a 0.05 level. The expected error of the prediction is below 25 % at any percentile. These errors are half to one third of the errors expected with the best prediction models available to date."

Jan 1, 2017

By Robert McClure, Carlton Lehman

Rendering safe explosives in an urban environment presents a unique challenge due to the safety concerns and disruption to the general public. Potential damage to the surrounding homes, businesses, utilities and transportation infrastructure are some of the major concerns when planning the render-safe operation. Engineering controls to mitigate blast effects, such as damaging air over pressure levels, material ejection and ground borne vibration, need to be implemented as part of the operation. Monitoring of seismic and air overpressure during these operations are needed to protect against potential claims when controlled or unplanned detonations occur.

Feb 1, 2020

By Robert McClure, Carlton Lehman

Rendering safe explosives in an urban environment presents a unique challenge due to the safety concerns and disruption to the general public. Potential damage to the surrounding homes, businesses, utilities and transportation infrastructure are some of the major concerns when planning the render-safe operation. Engineering controls to mitigate blast effects, such as damaging air over pressure levels, material ejection and ground borne vibration, need to be implemented as part of the operation. Monitoring of seismic and air overpressure during these operations are needed to protect against potential claims when controlled or unplanned detonations occur. Two recent render-safe operations conducted in and around urban environments dealt with deteriorated, sensitive dynamite and damaged blasting caps. Utilizing innovative neutralization chemicals and processes to render-safe the deteriorated dynamite, while protecting the general public, proved to be the safest, most environmentally responsible and cost-effective way to approach the problem. In both cases, the explosives, old dynamite and detonators were found in abandoned, unlocked magazines. The dynamite was in a significantly deteriorated state, which was evident due to the nitroglycerine found leaking in,around and under the dynamite cartridges. Iron wire permissible electric blasting caps were also found in a corroded condition with exposed explosives and un-shunted lead wires. With occupied buildings within 180 feet (54.86 meters) of the magazines, any procedure (e.g. transporting, countercharging, burning) that could potentially cause a detonation was not an option. In the event of an unplanned detonation during neutralization operations, several blast mitigation methods were employed to safeguard the site. This operation and a similar one with over 1,000 pounds of crushed and buried leaky dynamite were unique since all the explosives were rendered-safe and neutralized on site. The use of advanced neutralization products and filtering processes allowed for a safer, more environmentally responsible way to resolve the problem. The magazines and all residual solids and fluids were tested and confirmed by independent labs to have no explosives residues. The effluents were treated on site, tested and met safe levels, so they were disposed of at a local municipal wastewater facility.

By Mark Bosse

This is a paper demonstrating the use of a fixed wire and trolley system to deliver 2 or 5 lb cast primers (with 2 meter cap/fuse assemblies) deep into avalanche terrain. This avalanche terrain is mitigated using explosives prior to being opened to guests.

Feb 1, 2020

By Jaime Herrero, Santiago Gómez, Pablo Segarra, José Ángel Sanchidrián

This paper presents a mathematical model for the study of the 2D movement of blast bench faces based on the high-speed video analysis of three blasts at El Aljibe quarry (Spain) recorded at 2,000 frames per second. In these blasts, a set of bags of 0.75 × 0.75 m were placed in front of a selected blasthole defining a reference plane in which to study the kinematics of the movement. The burdens range from 3.86 m to 5.54 m, with a bench height of 12–13 m. An affine transformation system was calculated to convert coordinates from the video images into actual spatial coordinates. The problem is established from a multi-objective minimization approach in order to simultaneously optimize two defined objectives: trajectory fitting using Total Least Squares regression, and time–displacement regression using Ordinary Least Squares. Muti-objective minimization formulation produces Pareto plots of non-dominated solutions, i.e., optimal combinations of initial velocities and response times, (i.e. time between detonation and the onset of bench face motion). From the Pareto frontier, the most balanced solution is selected. Blast response time lasts only a few milliseconds and appears so brief at the frame rate used that it is difficult to detect visually. In this context, the bi-objective optimization-based approach proves to be a more robust tool than frame-by frame survey for quantifying such a rapid event while also maintaining a strong performance in the trajectory fitting task. Root Mean Square Error (RMSE) for the two minimizations average 0.22 m and 0.13 m, respectively. The initial velocities obtained range from 4 to 17 m/s, and the response times 0.7 ms to 21.7 ms. An analytical model is also presented for predicting fragments initial velocity and response time as functions of blast geometry and rock mass properties, explaining approximately 87% of the total variability.

Jan 26, 2026

By Diogo Fonseca, José Manuel, Nuno Fernandes, Blessing Taiwo

This research focuses on enhancing the synergy between blasting and primary crushing operations in quarries. A blast operation at dstgroup aggregate quarry in northern Portugal was simulated to fine-tune blasting techniques aimed at optimizing fragmentation indicators. The methodology involves conducting precise blast drill hole surveys, generating detailed terrain 3D models, and integrating these models into blast simulation software to enhance accuracy and optimize production efficiency. The study applies these simulations to test blasts, evaluating improvements in cost-effectiveness, crusher power consumption, and fragmentation efficiency using both aerial and terrestrial image analysis technology. The quarry key performance indicators (KPIs) guide the blast design simulations, ensuring practicality and relevance. The case study blast revealed that implementing optimum blasting techniques can enhance crusher throughput, reduce operational costs, and improve safety. This paper is part one of a three-part technical series where we aim to create a sampling procedure and establish a reliable baseline for the current state of operation. This baseline will be used in subsequent follow-up technical papers to make recommendations and improvements. The outcome of this study provides a framework for quarry operations seeking to enhance their efficiency.

Jan 21, 2025

By Jeff Hiedeman, Clint Sestrich, Christopher Hyle

Westslope Cutthroat trout have declined in distribution and abundance across their range and currently occupy about 59% of their historic habitat. Due to hybridization with non-native species such as rainbow trout, genetically pure populations persist in only 10% of that range. A westslope cutthroat trout population with relatively high genetic purity (97%) and conservation importance persists in less than two linear stream miles in the headwaters of the South Fork Madison River in southwest Montana. The relative purity of this population has been maintained through the presence of a downstream intermittent reach. However, spring flows fill the intermittent reach, creating a connection between occupied westslope cutthroat trout habitat in the headwaters and the habitat of competing trout species downstream.

Jan 1, 2011

By Bill Loviza, Jimmy Sanders

This report is not everything we would like it to be. Access to information concerning unresolved legal actions is a sensitive matter. Obtaining the information presented in this report was a challenge alone. The Tennessee Department of Commerce and Insurance, Division of Fire Prevention, the firms and individuals that elected to share information did so with various assurances of nondisclosure, confidentiality or anonymity. All those providing information did so with the expectation that the industry and ultimately the public would benefit from this effort. We offer special thanks to Assistant Commissioner, Fire Prevention, Emmett Turner, recently retired Director, Bomb and Arson, Dick Gardner and Director, Codes Enforcement, Randy Safer for support that made this endeavor possible. We make no claim with regard to being a scientific study. We did the best we could with available information. Our task was one of assembly, sorting and reporting. Where collateral information was available we used it.

Jan 1, 2004

By Robert Hopler

THE work that is being done by the Government to reduce the dangers of mining was brought out strikingly in the First National Mine-Safety Demonstration which occurred at Pittsburgh, Pa., on October 30th and 31st, under the auspices of the United States Bureau of Mines with the assistance of the American National Red Cross Society and the Pittsburgh Coal Operators’ Association.

Jan 1, 2012

By Langdon T. Mitchell, Karl Ingmarsson

The title is not referring to jewelry; nor is it about diamond core drilling. This article is instead about an emerging application for diamonds, hard rock percussive drilling with diamond drill bits. Diamond’s outstanding wear resistance has long been taken advantage of in core drilling. However, until now diamond has been less successful in hard rock production drilling in the mining and quarry industry.

Jan 1, 1999

By ISEE

Micrometer Crack Response to Vibration and Weather, by Prof. Charles H. Dowding of Northwestern University, adds to Prof. Dowding’s already important contributions to the industry with his “Construction Vibrations” books. This new book reports and interprets important data on crack response that are essential for differentiating the unseen effect of weather on structural cracking from the usually much smaller effect of vibration. In addition, the book contains detailed descriptions of data collection methodology.

Jan 1, 2010

By Johan Finsteen Gjodvad, Mathias Jern

The paper is part of the ongoing work of the Environmental committee of EFEE. To assist the European experts working with explosives one of the aims is to improve the common knowledge of similarities and differences between national legislation, standards or guidelines on vibration monitoring and other environmental monitoring during blasting in Europe and abroad.

Feb 1, 2020

By H. S. Venkatesh R. Balachander, G. C. Naveen

During the construction of a 1020 MW underground hydroelectric project in Bhutan a huge rock fall took place in the Downstream Surge Chamber (DSC) during March 2016. The total quantity of rock in the fall area is estimated to be about 1,50,000m3 (2.6 billion cubic feet), out of which about 25,000m3 (0.44 billion cubic feet) of muck was removed. The removal of muck was stopped apprehending that the cavity formed due to the rock fall may get further aggravated leading to widening and destabilising the adjacent transformer hall cavern or it might day light as the top cover was about 190m (623 feet). As the fall has virtually blocked the 314m (1030 feet) long cavern and divided it into two different chambers (south and north), and that the muck cannot be disturbed, it was decided to erect concrete wall on either side of the fall up to the cavern roof and then later address the filling of the cavity with appropriate fill material. As the access to the DSC was there for the southern side it was decided to extend a cable tunnel which was terminated at a distance on the north side of the cavern by D&B so that once it gets punctured into the north wall of the DSC it can be used to access the fall from this front too. This is a unique situation where in every blast approaching the DSC, the parting between them is diminishing and hence the tunnel blast will be exerting axial load on the parting wall leading to dynamic transient loading conditions and buckling may take place on the northern wall of DSC. This paper describes the various drill blast combinations adopted for successful excavation of this tunnel.

Jan 1, 2019

By Baohua Guo, Xuelin Yang, Tingkan Lu, Hailin Sun

The work presented in this paper mainly involves two parts. Firstly, the fundamental characteristics of the high pressure carbon dioxide gas fracturing technique (CO2 technique), including, a proposed method of TNT equivalence calculation, which is used to calculate the TNT equivalence of discharge of CO2 technique, and the comparison of the explosion volume generated by dynamite and expansion volume of liquid carbon dioxide is conducted to show the differences of fragmentation capacity between the two of them. Secondly, the coal seam fragmentation mechanisms of CO2 technique are proposed, including, 1) Gas jet cutting and penetration by shaped charge, 2) Gas volume expansion by changing phases of carbon dioxide, 3) Coal seam softening by destress blasting and 4) Coal seam fragmentation by discharge vibration, associating with the mechanisms, the equations for calculating fragmentation radius are developed and verified.

Jan 1, 2017