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By Thomas E. Lobb, Harry C. Verakis

Significant progress has been made in the reduction of serious injuries and fatalities resulting from mine blasting operations. Despite the progress, injuries and fatalities continue to occur. A leading cause of injuries and fatalities from blasting continues to be inadequate blast area security. Even though significant improvements in technology have been made, insuring adequate blast area security remains a challenge and requires constant vigilance. The advances in technology have created safer blasting products and have improved productivity and economics by enabling large, more efficient and effective blasts. However, as blasts grow larger in size, the complexity of adequately securing the blast area increases even more. Periodically the basic fundamentals involved in blasting safety should be reviewed, particularly for securing a blast site regardless of the size of the planned blast. Factors such as flyrock and toxic fumes must be taken into account to insure the safety of persons and property from the results of a blast. This paper examines the factors related to injuries due to inadequate blasting shelters and blast area security, and identifies mitigation techniques. The key concepts are: (a) accurate determination of the bounds of the blast area, (b) clearing employees from the blast area, (c) effective access control, (d) use of adequate blasting shelters, (e) efficient communications, and (f) training. Fundamentals are reviewed with an emphasis on analyzing task elements and identifying root causes for selected blasting accidents. Mitigating techniques are presented along with discussions and examples.

Jan 1, 2005

By S. Green, R. Yang

Blasting is a commonly used method for rock fragmentation in mining operations for mineral extraction. It involves breaking the rock mass into small pieces, and ideally creating micro fractures within the small pieces. Such micro fractures could significantly reduce the energy required for subsequent processes like crushing and comminution. Additionally, micro fractures would enhance the rock-fragraments fluid permeability thereby enhancing desired chemical reactions during certain processing operations. This paper presents recent developments of the Multiple Blasthole Fragmentation (MBF) model, which simulates blasting rockmass fragmentation. The MBF model allows estimating rock strains experienced during the blast, for various blast design parameters and geometries. The intent is to correlate these strains with created micro fractures in the blast rock fragments. Adjusting blast design parameters in the MBF model of explosive loading and delay timing allows blast optimization. Such optimizing would create desirable strains to enhance micro fractures within the rock fragments. This would improve mining operations by enhancing downstream operation efficiency, thus reducing costs.

Jan 1, 2024

By Richard L. Ash, Calvin J. Konya

Proper selection of the spacing distance between blastholes is fundamental to successful blasting. Its value directly affects the profitability of an operation. It also exercises control over adverse effects such as airblast, flyrock, generation of ground vibrations, and overbreak. One of the more significant factors influencing the spacing's specific value is the initiation firing time intervals used between blastholes. Examples are described to illustrate some of the problems that result when spacing and timing are not compatible.

Jan 1, 1979

By Richard D. Love

Competition in the aggregate industry of the 90's will be an over increasing really. With this in mind a quarry manager should always be comparing new and innovative concepts to increase productivity and reduce operating costs. In this paper, the author will present a comprehensive history of a drilling and blasting program that achieves these results. By employing proven methods and implementing new concepts, this program was proven to be a success over a ten year period.

Jan 1, 1991

By Kazuyoshi Kawami, Fumihiko Sumiya, Kunihisa Katsuyama, Yuji Ogata, Koichi Kurokawa, Yuji Wada

When explosives are detonated in the borehole where there is an air gap between the explosive charge and the borehole of inner wall, the shock cave in an air gap travelling ahead of the detonation front sill be generated. This shock wave is called the precursor air shock wave (PAS). The explosive is precompressed by the PAS, and as a result of that the detonation failure occur on occasion. This phenomenon is well known as channel effect.

Jan 1, 1994

By Benjamin Cebrian

Rock blasting at quarries represents multiple challenges not easy to see at first sight. Aggregate industries face similar or superior prices for explosives while extracting a material that usually is of less value of metal mining operations. Therefore, learning to optimize a quarry operation can be a perfect training for a position in blasting at larger metal mining operations.

Jan 1, 2010

By C. Lownds, U. Steiner

In 2008 a paper from the same source describing four actual cases of exposure of electronic detonators to lightning strikes was presented. It was shown that electronic detonators, like other initiation systems, are vulnerable to very close or direct lightning strikes. At the time of submitting this abstract no further incidents with lightning have been experienced. As a result of those original incidents, and in order to understand how the safety devices inside electronic detonators break down, two series of tests have been done, each with 2 detonator designs. In the first series detonators were subjected to capacitor discharges up to 6kV and 1kJ in energy. In the second series the intensity was increased to 800kV and 24kJ in energy. In the second series, more electrical energy was delivered to the detonator assembly than the explosive energy of the detonator. In both series both detonators showed a spectacular ability to resist very high discharge energies. The tests are described in detail with supporting photographs. The data for both pin-to-pin and pin-to-case (more relevant to lightning) are presented and discussed. The mechanism of breakdown of safety devices is now understood better and the learning is being used to design more robust products. This high-voltage testing is relevant in understanding how electronic detonators might initiate as a result of a very close or direct lightning strike 1. Orica

Jan 1, 2009

By Favreau R. F. Ph. D, Favreau Patrice

The article explains that the way to achieve a successful blast is by insuring that the explosive energy divides properly into the weakening action of the shock wave which is necessary to prevent large collar blocks and toe, and into adequate stress field intensity SS which is necessary to obtain good fragmentation size distribution at the crusher, as well as adequate burst out rock movement to achieve easy mucking.

Feb 1, 2020

By D P. Proudfoot, S G. Keith, D P. Onagi

A number of aspects of the Canadian concept for nuclear fuel waste disposal are being assessed by Atomic Energy of Canada Limited (AECL) in a series of experiments at its Underground Research Laboratory (URL) near Lac du Bonnet, Manitoba, Canada. One of the major objectives of the work being carried out at the URL is to develop and evaluate the methods and technology to ensure safe, permanent disposal of Canada's nuclear fuel waste.

Jan 1, 1996

By Andrew Theobald, Peter Dare-Bryan, Trevor Byers

The use of advanced modelling techniques and the timing flexibility of electronic initiation systems allows for unprecedented control over blast outcomes as shown in several complex blasting problems experienced by the open pit operation Xstrata Ernest Henry Mine (EHM) in north-west Queensland, Australia.

Jan 1, 2010

By Fred Baldassare, Marcia Harris, Kenneth K. Eltschlager

Surface mine blasting was recently investigated as a potential source of high concentrations of stray gases found in nearby residences of western Pennsylvania. In one incident carbon monoxide was detected in a home and in the other, high concentrations of carbon dioxide were found in a home. Both carbon monoxide and carbon dioxide are by-products of blasting. However, other potential sources of these gases may also exist in a residential setting. In each case, gas chromatography (GC) and carbon isotopic analyses were used to define atmospheric concentrations inside the homes, and to determine the source of a stray gas. Molecular and isotopic analyses provide geochemical evidence as to the origin and source of the stray gas. This paper discusses elements of a stray gas investigation and the analyses necessary to identify the source of a stray gas.

Jan 1, 2004

By Ruilin Yang

Kinematic approach of blast modeling refers to using the velocity, strain, or displacement as controlling parameters to model blasting, rather than the stress and the material constitutive relations. The rock stiffness or constitutive relations is very hard or impossible to obtain due to the complexity of the rock mass property.

Feb 1, 2020

By Jair Alarcón, Lucas Steffen, Leopoldo Muñoz

Flyrock is one of the most significant hazards associated with blasting in open pit mining, especially for blasting operations near communities. Flyrock can lead to severe injuries, fatalities, and property damage, compromising the license to operate. For this reason, defining exclusion zones is critical to ensure the safety of people and equipment. A very large radius will reduce the risk of flyrock; however, excessive exclusion zones can significantly impact the productivity of the operation and, in some cases, compromise the extraction of ore in critical sectors. Many mine sites use distances derived from pre-established standards, experiences from other mines, or still use simple methods for analysis, like recording blasts with a terrestrial camera and performing deterministic calculations to determine exclusion areas, applying an arbitrarily safety factor for people and equipment. In this paper we present a new approach that allows the calculation of the exclusion zone by measuring critical flyrock parameters with a high degree of accuracy through a new video analytics technology, this data then is used as input to calibrate probabilistic flyrock models to have more robust calculations, allowing optimized and safe exclusion zones. The proposed methodology leverages high-accuracy data and continuous monitoring to dynamically adjust D&B designs and exclusion zones, ensuring maximum safety without unnecessarily restricting operational efficiency. A case study is presented where the application of these new digital technologies allows precise prediction and control of flyrock trajectories, enhancing the accuracy of exclusion zone boundaries. In this case we successfully reduced the exclusion zone radius to 100m, allowing the ore extraction in a critical region close to the community safely. The study shows notable improvements in safety and productivity, including zero flyrock incidents and enhanced protection for nearby communities. The adaptive nature of these digital tools offers scalable solutions for various blasting environments. The paper concludes by recommending the integration of these tools into standard blasting protocols, highlighting the potential for widespread adoption in the industry to mitigate flyrock risks effectively.

Jan 21, 2025

By Marcus Neves, Eventomar Junior, Adilson Castro, Leandro Silveira, Sérgio Augusto

The collapse of the Vale S.A. mining tailings dam in 2019, a tragic event that shook Brazil and the world, had consequences that transcended the immediate pain and devastation. Among them, the suspension of rock blasting activities in several mines in the Quadrilátero Ferrífero region of Minas Gerais, Brazil. This measure, taken as a precaution and with the aim of ensuring the safety of nearby geotechnical structures and the population, had a significant impact on the mining production chain. To overcome these challenges and resume blasting activities in a safe and sustainable manner, the mining industry has been dedicated to developing and improving solutions. One of the promising alternatives is the signature hole technique, used in conjunction with attenuation laws. The complex geology of the Quadrilátero Ferrífero, with lenses of compact ores immersed in friable materials, the presence of discontinuity families, and the emergence of geological faults, requires detailed analyses and specific adaptations of the signature hole technique and constant monitoring of the vibrations to calibrate the attenuation laws to ensure compliance with permissible limits and safety of the operations. To demonstrate the methodology, a case study in Abóboras Mine was described. Additionally, the challenge of achieving the desired level of production while controlling vibration and slope damage has driven the development of new charging and timing techniques. To address this challenge, a comprehensive approach was undertaken. A substantial database containing more than 4,000 registers of blasting-induced vibration events from 520 blasts was meticulously compiled from 2020 to 2023, 6 different attenuation laws were established and continuously calibrated with 99.3% of compliance regarding permissible limits of vibrations. The successful implementation of these actions allowed for the resumption of blasting, increasing production from 10 million metric tons to 43 million metric tons per year assuring sustainable operation.

Jan 21, 2025

By Neal Lee

Reduced relief horizontally means an increase in energy expended vertically into the rock surrounding the stemming column, and potentially through the stemming column. The vast majority of holes in any surface blasting operation are afforded two horizontal relief faces at the moment of firing, whether by existing relief faces in front of and to one side, or previously blasted hole(s) in front of and to one side of the holes in question. When the energy expended in any hole on the blast pattern has less than two Horizontal Relief Planes or faces (referred to moving forward here as “HRPs”) available to it at the moment of firing, a higher percentage of the available energy is directed vertically. In the analysis of recorded videos by the author, one will note the fact that stemming ejection/flyrock is observed to a much greater degree from the center of almost all patterns when they are timed to “pull out of the middle” (“box cut" timed patterns). This is because the first hole to fire in each row has only one Horizontal Relief Plane, which significantly decreases horizontal avenue for energy release for these holes. This of course results in an increase in the amount of energy expended vertically. This paper proposes a novel methodology to modify the stemming to better use the explosives energy of each hole, while controlling side effects such as flyrock and airblast.

Feb 6, 2023

By Gavin Yuill, Kameron Ray

"The impact on vibration model accuracy by input data that is inaccurate was previously unknown, butthought to introduce significant error. This paper explores the impact of accuracy of different GPSreceivers, bulk truck density fluctuations, and charge weight location convention on the accuracy of the final vibration model output. GPS accuracy is compared between a professional Differential GPS, a “prosumer” GPS unit and a standard consumer GPS chip commonly found in cell phones. Bulk truck density fluctuations are compared from the density given by the operator and the actual cup density measured in the field. Charge weight locations explored are from the bottom of the blast hole, center of the powder column, and collar of the hole. The findings show that the weakest link in vibration model creation is actually low seismograph accuracy standards. Errors introduced from such are generally greater than those introduced from other sources."

Jan 1, 2017

By W. Birch, G. D. Rangel-Sharp, L. Bermingham

For many years, the accepted method of Measuring the Velocity of Detonation (VOD) in blast holes has been to use an electric cable of a constant resistance per metre. Thus as the wire is consumed by the explosive in the blast hole, the change in resistance is monitored and when this data is plotted against the time period of the in hole explosion, the VOD can be calculated.

Jan 1, 2011

By Carlos Pañura, Michael Geldres, Alejandro Rojas

The vibration waves are produced by the detonation of the explosive charges of each blasthole, analyzing the vibration waves produced by each blasthole, allow us to determine the optimal time between the detonation of each blasthole to reduce the vibrations of the production shot. Once the optimal time is found, it is possible also, to predict the vibration of the production shot (considering times and sequences) using predictive models. The waveform recorded includes information regarding the particle velocity and the dominant frequencies of the vibration.

Feb 1, 2020

By Gloria Contreras

The study aims to optimize the density of holes per tunnel section. The energy distribution, the one with the highest density, is used in the center of the diagram and is distributed homogeneously towards the contours with the lowest energies up to the contours to produce a perimeter control.

Feb 1, 2020

By Julia Creasey, Natalie Hodgson, Claire Ward, Craig Davies, Helen Sarginson

"Emulsion explosive producers are attempting to lower the cost of emulsion production by using lowquality ammonium nitrate in emulsion formulations. Low quality ammonium nitrate contains additivessuch as anti-caking agents and crystal modifiers which contaminate the emulsions causing instability. This presents a need for an effective emulsifier that will maintain emulsion stability under thesechallenging conditions."

Jan 1, 2017