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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 Roberto Folchi, Hans Wallin

Having so many norms and technical content of legislation to deal with is a problem that an explo-sives engineer has to face, especially when working at an international level. Each country has its own norms and legislation, sometimes even each other region or state, as if the physics of explo-sions, rock, concrete, and masonry characteristics would change across the borders. Both norms and laws are frequently out of date, being mainly developed at the beginning of the previous century and adjusted, piece by piece, to a technical and political context that is constantly changing, with adjustment being frequently adopted in a hurry, due to a problem arising such as that of internation-al terrorism. Sometime also, norms are not harmonized with those they intend to amend, so required explanations and new adjustments lead to a vicious circle that increases confusion, complexity and depresses the explosive industry.

Jan 1, 2015

By James R. Kennedy

The recent drop in world gold prices is driving many northern Nevada underground gold mines to look for new ways to improve and enhance current mining operations. Continuous improvement programs at these mines are finding the means to increase mine productivity while reducing total production cost. This paper looks at developments in the drill and blast program at Independence Mining Company’s Murray mine.

Jan 1, 1999

By Manuel Calderón

Chile is responsible for 30% of the global copper production; the world ́s largest. However, significant challenges are faced in this industry; declining grades (1.13% in 2002 to 0.61% in 2015), high cost of energy, scarcity of water, and environmental concerns. Mining trends suggest the future of the industry will be focused in the underground space, specifically due to the depletion of economically viable surface mineral deposits. For example, the largest block cave mineat Codelco ́s Chuquicamata mine is expected to reduce energy costs by 50% and dust emissions by 97%compared to the open cut mine. To access these underground deposits, critical infrastructure is required; horizontal tunnel developments, extraction levels, vertical raises, and ore passes with the on-time delivery of the highest quality outcomes being a requisite for successful project delivery (Lift 1 of 3 at Chuquicamata Underground has over 1000drawbells).One aspect that makes this scenario even more challenging for deeper underground operations is the increased risk profile (people, equipment, and geotechnical) that forms part of the general environment. Furthermore geotechnical risks should be considered and they include rock burst and windblast. The safe interaction with this environment must be sustainable throughout the full life of the project. This paper presents the Enaex group approach to addressing the blasting challenges and outlines the solutions created. Aspects such as rock mass damage occurrence as a function of blast vibration frequency content has been studied, as well as the development of blasting methodologies for guaranteeing the full 100% extraction of all infrastructure blasts, including the all-important draw bell volumes. The development of such infrastructure volumes in one single event using electronic detonators and the associated achievement of ambitious productivity goals, are described as a critical part of the successful construction of one of the most ambitious UG projects currently present on the world.

By C. E. Johnson, R. L. Bauer, E. M. Johnson

In industry, the strength of a blasting cap is often equated to the type of explosive it can detonate. Comparable cap strength is becoming less important as nearly all caps manufactured today can initiate high explosives, such as primasheet, with ease. Previous studies were conducted to assess the quantity of energy released by various detonators into the directional propulsion of the detonator’s casing. However, the question of how much of this propulsion energy is needed to initiate an explosive remains unanswered. This study will assess the fragmentation size and velocity needed to initiate a high explosive when they are not in direct contact. For this study, primasheet was used as the main charge as it is relatively insensitive and can be situated in different positions relative to the detonator. Electric, non-electric and electronic detonators were used to evaluate initiation potential. The primasheet is observed in response to being in contact with a detonator, and not in contact with the detonator at various distances and angles. This allowed the quantity of energy transferred into the primasheet to be observed and for the initiation of the sheet to be recorded using high-speed video. This study will report the energy necessary to initiate the primasheet at various distances and angles from the charge from a number of widely used, commercial, hot wire blasting caps.

Feb 6, 2023

By Peter Duniam, Stephen John Brace

2000 HIGH-TECH SEMINAR Blasting Technology, Instrumentation and Explosives Applications Orlando,Florida,USA July24-27,200O. Objectives:- After completing this session 1. Explain safety issues 2. Do simple initiation design 3. Describe how the system works 4. Demonstrate scanning, hookup, testing and firing 5. Describe hot to do a post blast check 6. Explain how to treat misfired detonators

Jan 1, 2000

By M Scoble

This paper will report on the application of data collected through the performance monitoring of large diameter surface rotary blasthole drii and electric mining shovels, in an integrated approach to blast optimizatiion.

Jan 1, 1992

By Ed Billington, Mike Shields

The trail blaster is faced with a wide range of workrelated challenges, not the least being the work setting itself. It is usually remote, being anywhere from 5 to 30 or more miles (8 to 50 km) from any road. It may be in mountains, high rock desert, or coastal rain forest, and can range from sea level to over 12,000 feet (3700 m) in elevation. The blaster may be part of a 2-person clearing crew, a 4-person maintenance crew, or a 10-person construction crew. The crew will usually be mobile, moving and working up to 10 miles (16 km) or more per day, relying mostly on their own backpacks to move camp, tools and supplies from site to site. Periodic resupply may be by helicopter, aird rop, or even “sherpa” groups, but most often will be by packstrings of horses and mules. The crew goes into the backcountry a n y w h e re from two weeks to three months at a time, and while there, its members “live the job” 24 hours a day, enjoying baking heat, torrential rain or mid-July s n o w s t o rms along with the truly glorious weather that c o m p e n s a t e s . So who is this blaster? Well, “he” may be she, since some of the top trail blasters are women. He/she will also be more than a blaster: Crews are small, so experienced members must be capable of handling the full range of trail work. Thus this blaster is also a driller, and usually also a bucker, snag faller, rigger, dry-stone mason, log and timber carpenter, bridge builder, mule p a c k e r, small-engine mechanic and, not least, camp cook capable of putting out a hot meal from a campfire , in a downpour, in the dark. Being in remote locations, often without reliable communication to the outside world, trail crews enjoy a remarkable degree of independence from “supervision.” With that comes the responsibility to make sound decisions which expedite the work, while promoting crew safety and welfare .

Jan 1, 2004

In all the industries that require blasting operations using explosives, there exists numerous unwanted side effects of the blast which may pose as environmental hazards. These hazards face prominence, especially in India, where there are very stringent rules and regulations governing the use of explosives. The environmental hazards associated with blasting operations as a whole can be tacked successfully to a certain extent depending upon the ultimate expectations of ,the post-blast effects and the limitations of the environmental obligations as specified by the authorities from time to time and from place to place. The main parameters which require attention to limit the post-blast results to the optimum level are ground vibrations, dust pollution, gas pollution, air blast effects, noise pollution & fly rocks etc.

Jan 1, 1995

By Darren Thorton, David Sprott, Ian Brunton

Blasting causes movement of the rock and can be detrimental to the accurate delineation of the ore and waste regions within the resulting muck pile. The consequences can be ore loss and dilution. However, ore loss and dilution can be minimized and significant increases in profit can be realized if the movement can be accurately measured. Various methods have been used to measure muck pile movement including poly-pipe, chain and sandbags but these have been either inaccurate or impractical. The Julius Kruttschnitt Mineral Research Centre, JKMRC, has developed an electronic blast movement monitor that provides accurate three-dimensional movement vectors following a production blast. From this information, the ore block boundaries in the blasted bench can be adjusted to compensate for the measured movement and then ore recovery can be optimised. Following initial development of the prototype technology, the JKMRC further developed and demonstrated the system in actual production blasts at an open pit gold mine operated by Placer Dome Inc.

Jan 1, 2005

By Dave Weymer

Falling timber in BC has always been a hazardous job. Huge, often rotting trees and steep, rugged terrain combine to create difficult and dangerous conditions. Death and injury rates are among the highest of any occupation in North America. In BC, the men that head out, saw in hand, are called fallers.

Jan 1, 2013

By Carl Lubbe, Ron Frye

Numerous articles have been written regarding the effects of blast control plugs in an attempt to quantify stemming ejection rates, air overpressures, fragmentation’and other parameters measured using these devices. In an effort to further attempt to understand the function of these devices, field and laboratory research conducted with various stemming devices was performed to enhance existing data sets and analyze otherphenomena that occur when these products are used.

Jan 1, 1998

By Rolf Schillinger

Blasting activities on the surface or underground necessarily involve the most sensitive aspect of environment remediation, human response or annoyance. Such effects are unavoidably characteristic of those activities. For this reason, blasting activities are governed by law and official regulations under surveillance of authorities, where companies and explosives engineers have to proceed within proper limits. Subject of the paper is a practical way of handling some necessary vibration standards being focused on blasting activities. The paper is based on the German Standard DIN 4150, Part 1 - 3, “Vibration in buildings”, Part 1: “Prediction of vibration parameters”, June 2001, Part 2: “Effects on persons in buildings”, June 1999 and Part 3: “Effects on structures”, February 1999.

Jan 1, 2006

By Randall M. Wheeler

The measurement and analysis of blast-induced ground vibrations are more complex than ever before. This is primarily due to the advancements made in microchip technology, mass storage utilities and the computer, which have allowed us to reduce and analyze data in a matter of moments instead of days. Terminologies such as Fourier transform, response spectra, cross-correlation, convolution, deconvolution and half-length frequency, etc. mean little to anyone except those who are experts in the field. A little understanding of the basic concepts behind vibration effects can help a beleaguered end-user feel more confident about what their measurements really mean.

Jan 1, 1992

By John E. Wiegand

"We will attempt to explain the basic workings of a modern seismograph and how the recorded data can be interpreted, not only for determining compliance to the regulations, but also in determining whether or not a seismograph record is accurate and valid. We will discuss some parameters that should be included in all seismographic recordings. We will give examples and use overhead slidesto show examples of both accurate and valid recordings, and tampered and inaccurate seismograph recordings. Much of the information presented will be basic in nature, and will reflect the opinions and personal experiences of the author. We ho'pe the listener will gain valuable information concerning the use and interpretation of seismographic data, as well as find interest and sometimes humor in the examples shown."

Jan 1, 1992

By Scott G. Giltner, Alex Schwenk

This paper is an update on a paper presented at the 2022 ISEE conference. The original paper presented how the mine operator desired to open up ore reserves near several mine structures including two crushers, the conveyor belt drive and the concentrator thickeners. In order to open up additional ore for extraction (over 3 million long tons or 3 million tonnes) it was necessary to blast out two benches near the mine structures. Since the two benches have been successfully shot, the mine has now conducted nine production blasts in this area at distances as close as 116 m (380 ft) to the two primary crushers. These production blasts are full size production blasts consisting of up to 300 or more blast holes. For these blasts the two primary crushers were still the critical structures as they were the production life blood of the mine. If the crushers were shut down due to any damage from the blasting, the revenue of the mine would be adversely affected. As with the initial bench blasts, two issues provided an extra challenge to the blast design. The first was that the blast holes were still considered large diameter at 12¼ inches (311 mm) and 16 inches (406 mm). The second issue was that the bench heights were short, with the average varying from 34-40 ft (10.3-12.2 m). This combination of large diameter blast holes with a short bench provided an unfavorable geometry for the goals established by the mine management. The mine management established the following goals. 1) None of the mine structures would be damaged by fly-rock. 2) Minimize the blast vibrations at the crushers. 3) The last goal was to produce a muck pile that could be dug easily by hydraulic shovels. Electronic detonators were applied to achieve the necessary control of the blast and optimal fragmentation throughout the mine. UAV surveys of the blast area were also conducted to provide a 3-D representation of the free faces and bench surface. The 3-D point cloud produced from this was used to measure the shape of the free faces. Once the shape of the free faces was quantified, it was possible to establish proper placement of the crest holes and develop a custom explosive load for each blast hole. The results of the nine blasts have provided what the customer requested. The peak vibration level at the crushers for the nine production blasts was 1.6 in/s (40.6 mm/s) at a frequency of 18.9 Hz. There have been no fly-rock or blast vibration issues at any of the nearby mine structures. As a result, the mine has been able to maintain its production with no downtime. The muck piles have been well fragmented with reports from the shovel that they have all dug well.

Jan 21, 2025

By Larry Schneider

I n the simplest application of a shock tube initiation system, the tubing acts as a “relay line” which passes a detonation signal from borehole to borehole. When the signal arrives at each borehole, it causes the detonator attached to it to fire. Such a single path constitutes a progressive series where each unit must function properly in order to activate the following units. Any application error, malfunction, or mistake in connecting any surface unit will stop the progression of the detonation signal through the system and result in a “cutoff” or misfire of the following charges.

Jan 1, 1995

By Lance McAnnuff

Whatever system is devised to control noise and ground vibration from blasting operations must present an effective compromise between the rights of the individual to be undisturbed by the actions of others, and the necessity for society, the whole of the population individually and collectively, to have the services and the products of commerce, industry and transportation along with the relaxation of recreational and cultural pursuits, all at a price within the means of the same society. One of the first jurisdictions in North America to attempt to quantify acceptable environmental limits for specific blasting operations was Ontario, Canada’s largest and most populous province. A process for development of guidelines applicable only to quarries and strip-mining operations was begun in 1974 and culminated with their inclusion in a “Model By-Law” published by the Ontario Ministry of the Environment in August 1978. This paper examines the process of development of the final guideline document and its application over the last 25 years. While acknowledging that the published guidelines for air blast and ground vibration control have provided a useful and generally workable framework for the purposes of land use planning and complaint or damage claim reduction, a number of flaws, weaknesses and misinterpretations connected with their application are identified. Recommendations for amendment of the controversial items are submitted with a view to making these and potentially similar guidelines in other jurisdictions, more acceptable to both government and industry.

Jan 1, 2004

By J. Lindenau

One of the significant benefits of electronic detonators is their safety, especially their relative insensitivity to extraneous electrical energy. The various brands of electronic detonators on the market have different resistance to electrical stimuli, but all have safety structures designed to afford a significant level of protection. A common source of extraneous electrical energy is lightning. This paper discusses the nature of the energy that occurs with a lightning strike and the resistance offered by electronic detonators. Four actual cases of exposure of electronic detonators to lightning strikes are considered. Electronic detonators, like other initiation systems, are vulnerable to very close or direct lightning strikes. The incidents are a reminder that all blast patterns need to be vacated on the approach and during the progress of a lightning storm. 1. Orica

Jan 1, 2008

By Adam Gray, Emery Gray

State-of-the-art seismographs can be employed to assist the blasting engineer in understanding the propagation of vibration waves generated by blasting. Wave traces and frequency plots are used to adjust shot loading and timing, especially around close or near- field structures. Successful close-in blasting vibration monitoring requires careful consideration of the following: Geophone locations Mounting of geophone both on structures and in the ground Differences between ground motion and structural response This presentation will discuss methods used to control and monitor blast-induced ground and structure motions. Case histories are presented to illustrate seismic monitoring used as a tool to control vibrations and guide the blaster in the design process.

Jan 1, 2005