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By Sedat Esen

"This paper presents a critical review of the fragmentation data obtained from some large open pit copper and gold mines. Database ncludes 35 mines with Uniaxial Compressive Strength values ranging from 19 MPa to 227 MPa (2756 psi to 32923 psi). Variation in the fragmentation data and the causes are discussed in detail. Quality assurance/quality control (QA/QC) in drilling and blasting was shown to have significant impact on fragmentation. In addition, controllable blast design parameters including drill pattern, powder factor, blast timing, stemming length, etc as well as the large blast sizes havesignificant potential to improve fragmentation. Feed size requirements of crushing and grinding circuits were discussed in detail. The paper discusses the effects of different size fractions (top size, 80 %passing size and % passing 10 mm (0.5 in)) on the downstream processes and the role of the fragmentation model in the mine to mill process. Blast domains based on rock strength and structure canbe established by using a fragmentation model which is calibrated using measured fragmentation data. This allows the blast engineer to compensate for changing rock characteristics and stabilize the ROMfragmentation size and result in increased crusher and mill throughput. Two case studies were presented to demonstrate the benefits achieved in downstream processes. Main benefits were reduced downtime at crusher circuits, improved mill throughput as well as reduced total operating cost. A simple relationbetween uniaxial compressive strength and powder factor was proposed using the database for the optimized mines as a guideline to allow site engineers to compare their sites against the other sites."

Jan 1, 2017

By Ricardo Chavex, Adrien Letellier

Flyrock remains one of the most critical issues in open-pit blasting. Despite the significant improvements made with modern surveying methods, the necessity remains to define sensible danger zones around blasting areas. Therefore, many semi-empirical models predict flyrock distances based on trajectory calculations and probabilistic adjustments. However, most are merely based on nominal parameters, even though a considerable amount of precise data is nowadays available thanks to modern measurement techniques using lasers, GPS, drones, and probes. These data provide accurate information about the actual field circumstances of a blast concerning geometry and rock-mass conditions. So how can we use and integrate them into existing flyrock models? The answer to this question can significantly improve the accuracy of flyrock prediction models and enhance safety. This paper will present a method to adapt existing models to actual field data using appropriate software and digital tools during the blast design process. In addition to calculating a more pertinent danger zone perimeter, this method provides an efficient and practical tool that helps prevent flyrock incidents. Indeed, it allows the blast designer and shot firer to be warned if there is a hazardous critical deviation due to local conditions. Moreover, it also enables blasters to communicate better and share the visualization of the blast-specific evacuation zone. The paper will also discuss how this method can be calibrated and how it has been used to analyze some actual flyrock incidents.

Jan 21, 2025

By David Porter, Nathan Rouse

The implementation of presplit perimeter control in underground mining as a method to decrease dilution yields positive benefits throughout the current and future mining cycles. A case study to understand the benefits of reducing overbreak and underbreak in a cut and fill mining cycle was performed to quantify the reduction in backbreak. The study was performed in a control section of the mine where a presplit perimeter control design was utilized for a length of heading. This control heading was then compared to the existing standard blasting design within the same mining zone. The comparison included multiple aspects of the mining advance including overbreak, dilution of waste, dilution of Cemented Rock Fill, bolt counts, and cycle times. Once mining in the control section was completed and mining commenced in adjacent headings, blast damage due to blast design could be quantified.

Feb 6, 2023

By Adrian Moore, Alan Richards

"It has been common practice to set blast vibration limits for structures using an “observational”approach whereby limits are set at a level based on observations of damage, or the lack ofdamage, combined with a tendency to further reduce the permitted level due to uncertainty. Suchan observational approach was used in the USBM RI 8507 to produce the frequency dependent‘Safe Levels of Blasting Vibration for Houses’ which has become a universal Standard for overthirty years."

Jan 1, 2013

By Ken Eltschlager, J Silva Castro, J. M. Hoffman, Braden Lusk

This case study focuses on analysis of sounds inside a house induced by blasts as result of surface mining coal in West Virginia and how to better communicate technical information to the public. The field study included a house wide vibration and sound monitoring system installed in a home which was subjected to blasts at varied distances and direction. The structure response was separated into ground vibration and airblast induced movement due to the differences in their times of arrival. This signal was then compared to the sounds recorded to determine which component of blast (ground vibration or airblast) induced the maximum sound. Findings shows that blasts at distances less than 762 meters (2,500 feet) had maximum sound responses from both ground vibration and airblast. While for blasts beyond this distance the maximum sound response was caused by ground vibration without exception. The kitchen generally created the most sound. The second phase of the study was to gauge the public’s response or preference to technical information. Three hundred and forty eight (348) telephone surveys were conducted in Logan and Boone counties West Virginia. Based on the survey, the public prefers units of pounds per square inch (psi) for airblast and millimeters of displacement for ground vibration. Ultimately a public relations plan was developed based on the results.

Jan 1, 2012

By Dick Green

During the recent troubles in Northern Ireland due to terrorist activities, there have been many buildings demolished or damaged by improvised explosives. This article explains about the Demolition of Churchill House in Belfast, the first controlled use explosives to demolish a high rise office building since the recent troubles started, and a further indication that normality is returning to the lovely city in Ireland.

Jan 1, 2006

By C. Breeds, K. Jeremiah, E. Jennings

Washington State has a well developed set of blasting regulations which have been promulgated by the Department of Labor using extensive stakeholder input, not only from citizens but also from manufacturers and representatives of IME, blasters in charge, blasting engineers, blasting companies, local and federal law enforcement agencies, fire officials, and local and state government representatives. WAC 296-52 therefore provides a foundation or platform for developing city ordinances for Washington State cities should a City wish to do so. On the other hand, Oregon’s code is based on OSHA 1926, Subdivision U, Blasting and the Use of Explosives which provides scant direction regarding the modern use of explosives. Reference is also made to ODOT Section 00335 - Blasting Methods and Protection of Excavation Backslopes. This paper examines two separate programs that have been developed by two Cities, one in Washington State and one in Oregon to further regulate blasting inside City limits and discusses why the lack of a regulatory foundation made one approach more difficult than the other. One of the authors was retained by the City of Kennewick, WA to develop their ordinance and has more recently followed and reacted to a pending ordinance for the City of Redmond, Oregon. The paper will compare and contrast the different approaches and comment on the reaction from both Blasters and the public. We also present a case study that involved blasting in an urban area of Oregon to prepare a foundation for a water tank. Controlled Blasting was carried out within 70-ft of residencies and within a community that had expressed reservations regarding blasting even though the work would make a significant contribution to the betterment of the community. Pre-construction surveys of residencies located in a large area surrounding the site were performed and a well-planned blasting program was carried out. Residencies were subject to vibration levels that were monitored using six seismographs that surrounded the site and these units measured vibration levels that were significantly lower than allowed by statute. There were complaints triggered by individuals reactions to blast vibrations which validated commonly held models of human perception but no damage was caused by the Blasting.

Jan 1, 2024

By Ed O'Connor, Per-Anders Persson, Manhong Zhou

This chapter deals with the concepts of shock waves and detonation waves together, because a detonation wave is really a shock wave, supported by the explosive reaction that the shock wave ignites and propagates as it travels through the explosive material. In the context of rock blasting, furthermore, there is justification for treating shock waves and detonation waves together, because the mechanical effect of the detonation in an explosive in a drillhole in rock is propagated and its effects are spread throughout the surrounding rock by means of a shock wave. The overall performance of an explosive in rock blasting or any other application is of course dependent on how much thermal energy is released in the chemical reaction that occurs when the material detonates, and on how much useful mechanical work the reaction products can do as they expand. A major portion of this chapter deals with the prediction and measurement of explosive performance, a subject which is now still in a process of rapid development.

Jan 1, 1997

By Ronald Ticona, Anaani Huaman, Andrea Lucero

Mine-to-mill optimization begins with a clear understanding and ongoing assessment of blasting, crushing, and grinding operations. Modification of blasting practices to optimize feed size can increase a mine’s throughput. However, this is only an initial step. To optimize the entire process and fully utilize downstream equipment, fragmentation must be measured at critical points along the size reduction circuit

Jan 1, 2019

By Ankit Jha, RICHARD AMOAKO

In this paper, we examine the challenges associated with the use of empirical rock fragmentation models. We highlight key parameters omitted by these models, and propose a machine learning approach that incorporates these parameters, leading to a simple, yet more accurate approach to blast design.

Feb 1, 2020

By L C. Taylor, H U. Lesiste

This paper provides a preliminary description of the properties of the output pressure (shock) wave of an end initiated, cylindrical charge of low height to diameter ratio in saturated sand. The properties of primary interest are the pressure wave velocity, peak pressure and rate of rise of peak pressure to within 1.4 charge diameters from the output end of the charge. The behavior of these properties is seen to be quite different from their behavior at more customary ranges in water.

Jan 1, 2013

By Bethany Witter, Dyno Nobel

In the past decades, a technological explosion has caused generational shifts. First, millennials experienced a technological shift to computers and cellphones. Next, Generation Z experienced a shift to smart phones and social media. These two generations are immersed in technology and are accustomed to constant connectivity. How do the extractive and construction industries gain the interest of younger generations and integrate them into the industry?

Feb 1, 2020

By Craig Adams, William Poe

Introduction The United States Department of the Interior, Minerals Management Service (MMS) is mandated under the Outer Continental Shelf Lands Act (OCSL A) and the Energy Policy Act of 2005 to oversee leasing, exploration, development, and production of mineral and renewable energy resources on the Outer Continental Shelf (OCS). Under these authorities, MMS is responsible for permitting and overseeing an array of offshore operations; some of which involve the underwater detonation of explosive charges. Explosives are most critical for their use in the severance of bottom-founded piles and well components during the decommissioning of OCS platforms and well abandonment work.

Jan 1, 2011

By Tyler Acorn

In December of 2009 an estimated one million ton slope failure activated a 10 million ton mass impacting use of the main ramp system in the Newmont Gold Quarry pit. The failure left behind a 400 foot (122 meters), vertical to sub vertical scarp feature and shut down production in the lower benches of the pit.

Jan 1, 2011

By J. Aravena, S. Gajardo, M. Ayala, P. Salinas

Both, Teck Carmen de Andacollo (Teck CDA) and Orica, work hard in the implementation of new technologies available in the explosives industry and drilling and blasting techniques, with the objective of sustainable development of their operations, regeneration, and protection of the environment, also considering the welfare and relationship with the surrounding communities. The open-pit Carmen de Andacollo mine is located adjacent to the town of Andacollo. Therefore, both companies together have developed the implementation of different techniques and technologies to mitigate the impacts of mining operations in the community, considering an important part of this challenge to minimize the impact of their perception of blasting by reducing the level of vibrations and sound pressure (airblast), in addition to the control of dust and smoke, strengthening sustainable production in harmony with communities. The technologies and techniques that have been implemented are the installation of airblast and vibration monitoring stations stands out, whose database has records since 2011. Using the vibration database, different models were developed to predict the vibration level of blasting in its design phase, achieving a difference of 4.1% between the estimated and measured values in the last year. Two techniques stand out to minimize the ejection of material, "Hydraulic Dome" and "Dual layer blasting", the first consists of water irrigation on the surface to be blasted and the second is an unconventional blasting technique, which was awarded in 2015 for its results in the environment. Also pre-splitting engineering has been modified in a positive evolution, where through different configurations, the airblast has been reduced by 15% compared with records from 2011 to 2022. Finally, due to the impact of operational restrictions, such as days available to blast, number of holes, and powder factors, the wireless initiation technology was implemented, which allowed reducing the limitations in the loading, generating an improvement in terms of blasted materials over conventional systems. Understanding the restrictions and challenges in terms of impact on communities, the correct implementation of all these techniques is important, and in conjunction with collaborative work, it has been shown and validated that producing in a sustainable and sustainable manner is possible.

Jan 1, 2024

By Manuel Gutierrez, Roberto Gomez, Juan Aravena, Johan Gjoevad

The use of explosives in mining operations is a process that involves the search for an ideal explosive for the type of geological condition of the mineral to be extracted. For the explosives present on the market the majority are based on Ammonium Nitrate. This as it is an ideal balance of high energy efficiency achieved with low development of gas emission. The manufacturing and loading operation of the explosive requires multiple process stages and different raw materials, which, if is not correctly supervised and controlled may cause the development of harmful gases or, in the worst case, even toxic gases. The majority of mining operations are located at remote locations without the presence of communities, and hence individuals, which could be affected by emission of the harmful or even toxic gases. In these operations the protection is mainly to protect the employees of the operation. However, if the operation is located near communities, the effect of these gases becomes a serious problem. The communities' perception of post-blasting gases, according to interviews carried out in this project, describes these as smells of black gunpowder, damp soil with a volatile permanence and medium intensity, sometimes a stinking tone is added. The legislation in Chile that controls the exposure of “workers” to different gases is Supreme Decree 594, 2019 (Decreto Supremo 594). Currently the Chilean Ministry of Environment and Sernageomin (Servicio Nacional de Geología y Minería) are taking actions to reform and strengthen oversight, seeking through a short law to provide more tools to the government to decentralize decisions in case of non-compliance with the decree. This paper describes the development and implementation of a permanent and remote gas monitoring system, considering the reasons for choosing the gases to be included in the equipment, the types of sensors and their capabilities, the way to verify in the field the correct functioning of the technology throughout the project, and finally how the data collected in the field is meeting the government's expectations in terms of permanent and online reportability. Additionally, it addresses the continuity of gas monitoring in the community that will disappear in the short term due to the expansion of mining operations, thereby ensuring the protection of both workers and affected communities.

Jan 21, 2025

By N Gkikizas-Lampropoulis

Selection of delay times to optimize fragmentation has been a controversial topic among researchers and blasting practitioners. This paper interprets previous experimental information on the effect of delay on fragmentation with the aid of some new experimental observations of the time of detachment of the free face of the blast as well as results of numerical modelling. It was shown that detachment of the burden occurs at delays shorter than the one which produced optimum fragmentation in the experiments, suggesting some fragmentation improvement due to gas action. In addition, at the spacing to burden ratio of the experiments, the damage zone from an earlier detonating charge extends the distance to the neighboring charge, essentially affecting the burden of some of the holes of the blast, at detonation time. Computer modelling demonstrated that increased spacing results is less overlap of stress induced damage zones meaning that there is less influence of delay on stress wave induced fragmentation. It was also shown that simultaneous initiation results in less back break, while increased back break may result even with short delay times.

Jan 1, 2016

By D. S. Preece, S. Silling, A. Bhuiyan, C. M. Lownds

GEM (Geologic Element Motion) is a Discrete Element Method (DEM) capability for blast-induced heave simulation with a very fast computational algorithm that can efficiently treat many different element shapes by utilizing alternating arcs and lines. GEM calculates rock motion from a knowledge of the gas pressure moving the elements. This requires an expression for the pressure vs volume, or the adiabat, of the explosion product gases. This work uses an analytical expression for the adiabat derived from the explosive’s properties. The effect of the explosive detonation pressure in crushing an annulus of rock, and setting up a shock wave, is termed Brisance. GEM incorporates a working hypothesis for the deleterious effect of Brisance on subsequent rock motion.

Jan 1, 2024

By H. R. Maggard, C. M. Bollinger

Solving the problem of detecting underwater explosions from "dynamite fishing" can be done by using a system of sonobuoys programmed to detect the acoustic waves from underwater explosions. The system includes three anchored sonobuoys, which have radio communication to a central station. Each sonobuoy will detect the direction the blast occurred, and then send the magnitude of the acoustic waves and the blast direction to the central station where the blast distance will be calculated. The central station can the send the coordinates to the authorities who can find the location using GPS systems onboard their boats.

Jan 1, 2004

By Charles Zdazinsky

Many blasting applications in the mining industry demand that the hard rock being blasted remains structurally competent. For example, pre-splitting is a common technique to reduce fracturing, and operators of dimension stone quarries use this blasting method to eliminate overbreak. When pre-split design parameters are not applied correctly, there will be a redistribution of stresses within the rock, resulting in Blast Induced Rock Damage (BID). Advances in geophysical technology are enabling blast technicians to monitor BID and then use the results to correctly design their blasts.

Jan 1, 2011