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By C. Mick Lownds, Dale S. Preece, Ali Bhuiyan

FDM (Fracture Density Model) is a three-dimensional mechanistic model of blast induced rock fragmentation. FDM uses several computational mechanics algorithms to simulate the effect of blasting in different rock types. Earlier, FDM was successfully exercised to simulate 29 small scale shots from the United States Bureau of Mines (USBM), and 6 full-scale bench blasts at the Bararp dimensional stone quarry in Sweden. Excellent agreement was obtained for those shots, and the results were documented in earlier publications. One of the drawbacks of previous ver- sions of FDM was its inability to predict the fines, specifically in Bararp quarry simulations. Ac- curate predictions of fines can be very useful in reducing energy consumptions during down- stream comminution processes and improve the mine-mill operation efficiencies. In this paper, we propose a newer algorithm that can predict the fines as well as the coarse fragments in Bararp with reasonable accuracy. The model was also applied to an open-pit Copper mine with heavily jointed rocks, and it produced very good fragmentation predictions for the full range of fragment sizes. Comparisons with the sieved fragmentation data (for both Bararp stone quarry and the open- pit Copper mines) show great potential for this updated version of FDM in modeling the entire range of fragment size distributions in mining and quarrying applications.

Feb 6, 2023

By J. Silva, T. Worsey

The Worsey-Silva equation determines the optimal row timing for the smallest fragmentation and allows fragmentation models to be adjusted due to row timing. The equation utilizes the concept of dynamic confinement to determine when the best time to fire the next row or sequence series would be if the smallest fragmentation is desired. Full-scale testing was conducted at an aggregate quarry in Ontario to support the theory and equation. The full-scale testing comprised six (6) blasts, two (2) different contractors, and three (3) different sequences. The test parameters were kept consistent, besides changing the timing between sequential charges to explore the timing sequence’s influences on fragmentation. From this research, the theory of dynamic confinement relating to row timing was discovered, and the equation to determine the optimal timing for the smallest fragmentation was derived. An equation to adjust fragmentation based on row timing was derived from the full-scale testing and literature review. The Worsey-Silva equation can be used with other fragmentation models as it takes the fragmentation results from the other models and adjusts them based on the row timing used. The paper explains the theory behind the equation, the research supporting the findings, and the developed Worsey-Silva equation for row timing

Jan 1, 2024

By Tristan Worsey, John Henchion, Nathan Rouse, Yannick Lauras

"This paper presents an approach used to plan and evaluate drill and blast trials for a mine that currently mechanically excavates in-situ rock. The document presents the approach used to plan the trials, the key performance indicators (KPIs) that were necessary to evaluate the mining methods, the test matrix used during the trials, and the results of the trials. The trials, which occurred as part of an overall drill to mill optimization project at this site, helped to evaluate various blast designs using fragmentation results,drilling and blasting costs, and downstream costs. This project was unique in that (1) drill and blast methods were trialed on multiple rock types and various bench heights using a range of blasthole diameters and powder factors and (2) the load and haul costs were evaluated using a range of loading equipment, from 66 tonne (73 ton) excavators up to 250 tonne (276 ton) excavators. A ten year net cost financial evaluation of the material extraction alternatives was also prepared for the site management. Ultimately, the process of evaluating the drill and blast trials helped the management decide whether to continue extracting using mechanical methods or to introduce drill and blast methods to extract the rock."

Jan 1, 2017

By Mathias Jern, Ruilin Yang

A blast vibration model has been developed that simulates effects of almost all blast design parameters on the blast vibration peak particle velocity (PPV) from a production blast with multiple blastholes at a given point of interest in the rock. The velocity of detonation (VoD), initiation points, explosive types (density, VoD, energy), charge decoupling, and decking in each blasthole are simulated along with other blast design parameters. The information from signature hole blast vibration and the blast design are the input to the model. The model can be used to assess blast damage in proximity of blastholes as well as far field vibration PPV.

Jan 1, 2019

By Michael A. Barbaglia, Mark William Withey

The lift shot is an essential blast design in the execution of mine creation and expansion plans. Whether it be opening a new quarry, creating a new level in an existing operation, or for control of water, lift shots are utilized to create the desired results. Lift shots by their nature differ from conventional production blasts because they have no free faces for relief of the blast. Due to this fully confined state, the primary direction of the rock movement is vertical, and the potential for excessive vibration and fly rock generation is great.

Jan 1, 1994

By Rajesh Sonkar, Sanjeev Kumar

The deployment of Dragline machines in opencast coal projects involves huge capital expenditure as well as operating costs. The mine operators always endeavor to ensure smooth excavation of material by the Dragline machines while meeting the major objectives of safety, minimal disturbance to environment and optimal operating costs. Optimization of fragmentation through well designed blasts is fundamental in meeting part of the objectives is good fragmentation of rock or mineral proposed to be lifted by the Dragline machine. If the overburden lying over mineral is not properly fragmented, it may result in formation of ‘Toe’ the removal of which is the most arduous task in opencast coal mines. The mine operators always endeavor to achieve best possible results in blasting to ensure smooth operation of the high cost Dragline Machine. However, despite continuous efforts by the blasting engineers involved in bench blasting for the machine, the formation of ‘Toe’ is an ever nagging problem faced in large opencast coal projects eventually reducing the overall operational efficiency of mining.

Jan 1, 2011

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 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

By C. Zuniga, S. Combrinck, C. Peters

Agnico Eagle Gold have partnered with Enaex Australia at their Fosterville gold mine to leverage a combination of drill and blast technologies to optimise underground development mining. The mine is the first site globally to collaboratively develop and trial Enaex SWIFT electronic development detonators, which utilise a novel approach to the user interface, simplifying implementation and enabling the benefits of electronic initiation without the complexity of a conventional system. This has been combined with the use of a Sandvik 422i smart jumbo, and the Enaex underground emulsion charging unit with the capability to tailor the delivery of explosives as required and report on a hole-by-hole basis. The combination of these technologies enables full engineering oversight of the development cycle, in turn enabling optimisation of this process in a historically conservative application. The methodology for leveraging these technologies is to bore a controlled and defined blast pattern through using a smart jumbo, load the blast holes utilising lace loading to deliver a desired quantity of ammonium nitrate emulsion per hole, with the ability to reduce chargeweight for perimeter control, and utilising Enaex SWIFT electronic detonators with flexible template type pre-defined delays to initiate the blast holes. Subsequent to firing and excavation the performance of the blast in fragmentation, advance efficiency, and overbreak and underbreak is measured and reviewed. This is then used to optimise the development cycle and apply to other parts of the mine.

Feb 6, 2023

By Richard Givens, Thomas Baginski

Technological advancements in warhead designs and implementations have driven the development of arrayed initiation networks of highly accurate, highly reliable, and extremely safe detonators. Recent development efforts have produced advanced Exploding Foil Initiator (EFI) based systems that have been adapted for civilian use in commercial blasting applications.1,2,3,4,5 This novel, high technology system promises multiple improvements and advantages over the manufacturing, transportation, tracking, storage, inventory and field operation of current detonator systems. Ultimately the insertion of this technology would result in fielding a Non-Energetics Based Detonator (NEBD). Insertion of complementary technologies into the detonator’s supporting systems would greatly advance current detonator hardware/software.

Jan 1, 2011

By Christodoulos Xiouris, Ali Reza, James Karnesky

A rocket parachute signal flare is often used to signal a maritime emergency. In the general operation of these devices, a solid rocket motor propels a metal body to an altitude of approximately 1000 ft (305 m). At the end of the rocket motor, a propelling charge drives a signal flare and parachute out of the metal body and ignites the flare, which then burns for approximately 40 seconds as it falls to earth. In this paper, we describe an engineering investigation of an accidental ignition of a rocket parachute signal flare, which caused injury to the user. T

Feb 1, 2020

By Advanced Initiation Systems Inc

10 years in R&D Last 5 years available commercially Worldwide Met strict approvals for manufacturing and use

Jan 1, 2004

By Paulo Couceiro, Manuel Lopez Cano, Carlos Rodgriguez Calvo

Apart from its difficult execution, underwater blasting is one of the most critical operations of the blasting techniques; mainly because of the ground vibrations - normally associated with low frequencies -, destructive hydraulic shock waves, the difficult coordination, and high costs. To solve these challenges during the underwater blasting on the expansion program for the Panama Canal “Widening and Deepening of the Pacific Entrance and the South approach Channel to the Third set of Locks of the Panama Canal”, a new method to blast using bulk explosive, developed by MAXAM, was used. The project was successfully executed, and more than 800.000m3 were blasted in less than 5 months, jointly with the biggest underwater drilling platform ever build, the Yuan Dong 007, with ten hydraulic drills on board guaranteeing a high production, excellent fragmentation result, total control of the vibration levels, no complain of the neighborhood surrounding the area of the project and simple local logistic due to the classification of the main product used (an oxidizer classified as 5.1). That was finally sensitized down in the hole.

Jan 1, 2011

By Nickolas Vlahopoulos, Nicholas Stowe

A concept has been proposed for the focusing of underwater energy. An array of spherical TNT charges is used to achieve this aim. The goal of the present research effort is to model such a system and identify optional arrangement and detonation timing schemes. A fast-running model is necessary to perform optimization analysis due to the highly iterative nature of most optimization algorithms. This requirement renders the use of sophisticated numerical solvers impractical. An analytical, physics-based model must be developed to satisfy the demands of the multiple charge optimization problem. This model must capture shock propagation speed, pressure-time histories throughout the fluid domain, and multiple charge interaction phenomena. Such a model is presented herein.

Jan 1, 2012

By Christodoulos Xiouris, Ali Reza, James Karnesky

A rocket parachute signal flare is often used to signal a maritime emergency. In the general operation of these devices, a solid rocket motor propels a metal body to an altitude of approximately 1000 ft(305m).At the end of the rocket motor, a propelling charge drives a signal flare and parachute out of the metal body and ignites the flare, which then burns for approximately 40 seconds as it falls to earth. In this paper, we describe an engineering investigation of an accidental ignition of a rocket parachute signal flare, which caused injury to the user. The components of the flare involved in the accident were inspected via x-ray and microscopic imaging techniques, and compared with those of unfired flares recovered from the same vessel. Chemical analysis of residue on recovered components from the accident flare was also performed. These comparisons were used to determine the likelihood that the actuation mechanism had been deliberately manipulated. In the subject model of the flare, ignition of the rocket motor is accomplished through a percussion cap which is struck by a firing pin. Prior to activation, the firing pin holds down a pre-compressed spring. We present a comparison of the ignition system of the incident flare with those of other rocket parachute flares, which do not incorporate any stored mechanical energy.

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 Hernan Navea, Carlos Alvarado, Exequiel Nuñez, Matías Suarez, Jhon Silva, Bryan Townsend, Bryan Caceres, Felipe Pontanilla

Nowadays, technology dominates all aspects of human activities, and drilling and Blasting (D&B) is no exception. In most cases, the use of technology in D&B is focused on controlling individual activities such as drill performance, drilling advance rates, truck loading performance, etc. Still, in very few instances, the advantages of using technology along each D&B activity and how this influences the D&B results are documented. This paper shows how technology is applied to create a “relative hardness” model for the mine Caserones in Chile. In the future, the model can relate the relative hardness parameter to several variables, including excavation rate, fragmentation results, and vibrations. It can also be used in the explosives loading process, similar to the model used by Dyno Nobel’s Differential Energy (DE) technology. In the relative hardness model for Caserones, a design is loaded in the drill system, and data is collected during the advance of the blasthole. The collected data includes rpm, torque, pressure, etc. Then, an algorithm using the measured variables while drilling and known relationships between the properties of the rock and the drill's performance is used to classify the average relative hardness of the blasthole in four intervals: hard, medium, soft, and very soft. Optimization techniques and models used in the oil and gas industries to analyze drilling performance were adapted to implement the algorithm. The model uses the concept of mechanical specific energy (MSE). Using the data from the drill, the algorithm identifies the depth where the MSE reaches a minimum to calculate the “relative hardness” for the blasthole under analysis. The results are presented in maps highlighting the areas where hard, medium, soft or very soft rock masses are expected. That information can be used to anticipate areas where explosives with higher energy need to be used or to predict areas of the blast with additional digging difficulties and then lower loading rates. The paper shows examples where “relative hardness” maps are compared to drilling speed excavation rates and other variables.

Jan 21, 2025

By C. T. Aimone-Martin, B. M. Meins

This paper compares response of large urban structures to small charge weight, ultra-high frequency rock blast excitation from contiguous excavation to that of houses to more distant, larger charge weight blasts. Time correlated responses were measured for both structures at the corners, top and bottom of the structures as well as in the foundation rock below the bottom. The comparison allowed the following conclusions: Close-in blasting with direct rock to building wave transmission imposes short wave length excitation which fails to excite the large, massive structures synchronously whereas the more distant blasts do synchronously excite houses. The larger urban structures respond predominantly in wave transmission mode where there is a noticeable difference in time, frequency, phase and amplitude of motions measured at the bottom and top corners of the structure. Excitation motions along the base of the larger urban structures also differs in time, frequency, phase and ampli-tude. The short wave length of the excitation motions leads to attenuation of the peak particle veloc-ity along the base. Ultra-high excitation frequencies, which are much higher than the expected struc-tural natural frequencies, lead to deamplification for all events for the large urban structures.

Jan 1, 2018

By Kristen R. Bingham

"Today, more than ever, drilling and blasting contractors are challenged to manage the ever-changing risks associated with blasting operations. New neighborhoods are encroaching upon mine sites and blasting projects are confronted with increasing scrutiny by permit issuing authorities and nearby residents disgruntled by new construction. The act of transporting explosives material to and from thejobsite is far from easy and trouble-free. At the same time, the pressure to stay in compliance with the growing number of government regulations continues to mount. While new tools and technology are appearing in the workplace to address some of these challenges, losses still occur. Can the datagenerated by this technology help drilling and blasting contractors make better decisions? While basic risk management principles are still applicable, do new tools and technology assist in the effort to prevent losses? What are the downsides? In this age of new technology, is face-to-face interaction still necessary? While technology is certainly a useful component in the drilling and blasting world, can it be helpful in defending claims?"

Jan 1, 2017

By Italo Onederra, Miguel Araos

"In order to characterize non-ideal explosives, the explosives industry rely on unconfined velocity ofdetonation tests and where possible underwater pond tests. The information obtained from such tests isquite helpful, however it cannot tell us much about the dynamics of the detonation reaction process. The detonation process has been studied for ideal explosives and the reaction zone length have been measured. However, for non-ideal explosives, that type of information is not available. Therefore, the primary aim of this work was to capture the detonation process of a non-ideal explosive using high speed video camera to determine the zone length."

Jan 1, 2017