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By Timothy Smith, Matthew Ryan, Dr. Anthony Konya

Hybrid specifications are a relatively new style of specifications specifically for the drilling and blasting industry that has seen widespread use over the last decade with the U.S. Army Corp of Engineers. This paper analyzed how this methodology was applied to develop this specification for the Soo Lock Deepening Project.

Feb 1, 2020

By Don Thompson

The Minntac Mine drills and blasts approximately 75 million long tons of taconite per year. This requires drilling one million feet of 1 6-inch diameter holes. We are in the process of replacing our old generation rotary blasthole drills (Gardner-Denver 120's and Bucyrus-Erie 61R's) with new generation rotary blasthole drills (Bucyrus-Erie 59R's and P&H 120A's).

Jan 1, 1998

By Michael Wieland

The thermodynamics work-principle was used to develop the rupture-fracture-throw (RFT) model for ranking the performance of reduced-density explosives when shot in rock or other stratum. The RFT model revises techniques used for the rock-water-jelly (RWJ) model, where the reaction-zone remains trapped within the rock/stratum. Therein, ranking of performance refers to trends for the two resolved components of the total expansion work: the reversible mechanical work taken as the heave and the residual irreversible portion, taken as the undissipated shock. For numeric tractability, the RFT and RWJ thermodynamic efficiency were taken equal, while the RWJ late-stage confinement was replaced with restrained venting through the rock, to render the RFT inefficient heave. The transfer of heat from the reaction-zone was neglected and the root-power formula was used to render the gas-covolume. Ranking trends were found for a generic charge formulation over a wide ranging density, with underwater results noted for comparison. Realistic compositions, some with natural resource materials, were treated for just typical and reduced density. Rock characteristics, ranging from hard rock to weak stratum, were represented by their density and rupture compression strength. Quantitative test results for shock or heave in rock remain difficult, so qualitative guidelines remain helpful when reviewing the graphic trends. Theoretical refinements for rock fragment size-distribution remain under development, though some relationships are touched upon to gain insight.

Jan 1, 2011

By A. S. Tawadrous

This paper is an evaluation of Artificial Neural Networks (ANN) as a tool in the design of the geometry of surface blast patterns. The built model uses eight different parameters, which affect the design of the pattern. Those parameters are rock type, stratification, blasthole diameter, bench height, type of explosive, priming position, powder factor and fragmentation size required. The network was trained to predict burden and spacing of the blast pattern. The model was built and trained (back-propagation technique) using 43 case histories collected from the literature. The model has then been validated using 16 cases from operational quarries.

Jan 1, 2006

By Hung Tran, Qian Liu, Patrick Andrieux, Dave Counter

Blast damage in open stope mining has been an important concern in controlling ore dilution. Severe damage to the surrounding rock mass can result in the caving of waste rock and/or backfill materials, as well as general instability of the ground. The blast damage study conducted at Kidd Mining Division in 1995 was aimed at measuring the damage zone around blastholes and at identifying other factors which influence the damage. An approach and methodology developed mainly by Blastronics, together with Noranda under a project with the Mining Research Directorate, was adopted for this project. The principle was to combine vibration measurement results with borehole camera observations to derive the blast damage criteria at the specific site. The Holmberg-Persson Equation was used for the regression of near-field vibration data. The damage criteria was examined with both borehole camera observation results and rock elastic and mechanical properties. Details of this methodology, including instrumentation, are reviewed in this paper and an implementation case study of the blast damage evaluation is presented.

Jan 1, 1998

By Blair Jackson, Tjaart Louw

Martha Mine, owned by Newmont Mining, Australia appointed Macmahon Contractors (NZ) Ltd as the mining contractor to drill, blast, and crush and convey ore for processing, followed by construction of a tails dam facility from the waste material. The open pit is located 140km(90miles) south east of Auckland, New Zealand in the middle of the township of Waihi (the main street of the town with a population of 3,500 is 90m from the perimeter of the open pit mine). Mining must proceed at 325,000m3 (of which involves blasting approximately 11,000 holes per month, in order to ensure continued ore supply.

Jan 1, 2003

By Curtis G. Kremer, Jeffrey L. Brummert

Blue Circle Cement's Ravena, New York quarry mines approximately 6.7 million tons of limestone per year. Blasting occurs approximately twice a week on three separate benches. Shots average 60,000 tons but can range up to 140,000 tons. Ongoing scrutiny of the drilling and blasting program allows for maximum blast efficiency which results in lower overall mining and crushing costs. Close cooperation between management and explosives supplier assures Blue Circle Cement's objective, "To develop, implement, and continuously improve a measurable drilling and blasting system that will optimize the total mining and crushing costs while ensuring compliance to safety and maintaining or reducing the environmental impacts of blasting".

Jan 1, 1994

By Ron J. Elliott, Corry Coumans

The following is a detailed description of the blasting procedures used in the successful demolition of the Stave River bridge, Mission, British Columbia, Canada. This highway bridge spans a highly sensitive salmon-spawning river. Demolition of the bridge took place in a high liability situation in close proximity to sensitive structures. The new highway bridge carrying an exposed 150mm diameter gas line was located only 1.5 meters away. The bridge piers were blasted only seven meters from overhead power lines. Control of blast vibration, flyrock, and underwater overpressure was critical to the success of the operation. Electrical sequential blasting was used to ensure that blast vibration on the new bridge structure was kept below 50mm per second.

Jan 1, 1998

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 Andrew Ritter, Victor I. Montenyohl, Stephen R. Winzer

Thirty-seven open pit production blasting operations have been monitored using high-speed cameras running between 500 and 7000 frames per second. Analysis of the resulting films reveals irregularities in timing including sequencing errors and crowding (holes firing less than 8 ms apart), confirming results of laboratory testing of ms delay blasting caps (Winzer, 1978). Where blasting parameters are otherwise constant and within recommended guidelines (stemming, spacing, burden, etc.), timing problems dominate the overall performance of the blasting operation. Model tests in layered Homalite 100, designed to simulate joint or bedding planes in rock, indicate the importance of the stress waves generated by the explosive in developing the crack network which is ultimately responsible for the fragmentation seen in the resulting muckpile. These mechanisms are strongly supported by high-speed film studies at Pinesburg, Maryland. Experiments in controlling relief in deep shots (where depth approaches the lateral extent of the bench blasted) using borehole geometry and hybrid initiation systems (electronic timer and pyrotechnic delays) were carried out. The results suggest that the 1 me/ft. of burden guideline developed by Bergmann et aI., 1974 is too short, and that much longer times are necessary to optimize fragmentation and muck digability. Longer times are found to reduce noise, vibration, and flyrock.

Jan 1, 1979

By Sebastián Seria, Jorge Álvarez, Diego Cáceres

The capacity to break the rock into adequate size fragments and in a cost-effective way is one of the main challenges in large open pit copper mines in Chile. That capacity is often compromised by the accuracy of geological estimations and the resources allocated by the mine site to update those models, making the blasting design highly dependent on that input and in consequence, blasting results. Given these opportunities, having an alternative method to input estimated key geological parameters allows blast designers to modify their designs and apply the appropriate energy to achieve the desired results. By using measurement-while-drilling data from boreholes and a few samples of actual, widespread, hardness measurements on site, we can deliver an updated cost-effective hardness estimation that is used as an input to improve the blasting design and its results on fragmentation. This estimation is delivered as a hardness interval – often in MPa units- related to the position of actual drilling measurements. In addition, having a sufficiently large drilling dataset allows us to predict hardness in new, undrilled areas near already measured boreholes, serving as a prior estimation available before pattern design. The use of these estimations, applied to several copper mines in Chile, allow us to more accurately determine explosive amounts and borehole drilling, which directly contributes to more productivity and efficiency in mine site operations. The results are often related to narrowing the gap for fragmentation results, even so, in some cases that will be related to direct savings in Drilling & Blasting process in a range 5-10% of the budget, due to powder factor changes.

Jan 26, 2026

By R E. Langston, S M. Gazioglu

A preconstruction inventory program was conducted to determine the existing conditions of residential, non-residential and all other structures within 2,000 feet of the blasting limits for a highway excavation site in Asheville, North Carolina. Prior to major production blasting, eleven test blasts were detonated to establish site specific propagation parameters in order to develop contours of maximum allowable explosive charge weights per delay. The method of scaling distance by the square root of charge weight per delay was utilized in developing the contours of allowable charge weights. The charge weight contours were revised during blasting operations as additional vibration data became available. The effects of blast induced vibrations on a nearby water storage reservoir, a nearby vehicular tunnel and other adjacent residential and non-residential structures were observed and monitored over a period of two years of blasting operations.

Jan 1, 1980

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 Stephan Iversan, Janae Singer

High resolution seismic refraction tomography has proved to be a useful tool to effectively estimate depth of blast induced damage in rock. Excavation blast damage can be as shallow as 1 to 2m (3 to 7ft) and requires resolution at a fraction of a meter for effective imaging. We used an accelerometer with flat frequency response to 1000Hz to record data at spacings of approximately 0.25 to 0.5m (0.8 to 1.6ft) along mine walls. The resulting tomograms of P-wave velocity show low velocity zones which we interpret as residual fracturing from blasting. Experiments on a concrete test block and at two underground mine locations give results that are consistent with fractured rock transitioning to competent rock.

Jan 1, 2009

By Thomas Palangio, Blessing Taiwo

Image-based fragmentation analysis is increasingly utilized in blasting operations to evaluate particle size distribution in a non-intrusive and efficient manner. However, the accuracy of optical granulometry systems can vary significantly with particle size. Higher precision is typically achieved for larger fragments, generally those greater than golf ball size when using drone-based orthomosaic analysis. In contrast, the detection and delineation of fine particles become less reliable due to constraints such as pixel resolution, particle overlap, and partial burial within the muck pile. This variability does not undermine the value of image analysis but rather highlights the need for a deeper understanding of its operational thresholds and the integration of complementary methods or calibration approaches to improve its reliability across the entire particle size distribution. Technologies such as WipFrag, originally developed in the 1980s, are designed to conduct in-situ fragmentation analysis within complex blast environments, where fines are often obscured by larger fragments. The challenge becomes more significant in blast rounds exhibiting wide gradation ranges and increased fines, particularly resulting from excessive energy concentration in high-pressure zones near the borehole. Previously, this issue was addressed through methods such as analytical correction, zoom-merge correction, and empirical calibration using Rosin-Rammler and Swebrec distribution models. However, these traditional empirical calibration approaches, particularly those tied to distribution functions like Rosin-Rammler have shown limitations, especially in accurately representing the fine region of the fragmentation curve. In contrast, the recently developed xP-fan model, which incorporates the relationship between powder factor and fragment size, introduces the fragmentation energy fan principle which Kuz-Ram model does not entail. This paper presents a study on the application of the novel xP-fan calibration to enhance the accuracy of optical granulometry systems. The findings demonstrate how xP-fan help calibrate the fine region of the PSD without deflecting the maximum size.

Jan 26, 2026

By Paul Worsey, Gillian Worsey

The explosives industry is about to reach a critical turning point in human resources. The average age of employees of the largest US explosives company is over 50 and an estimated 5,000 engineers are due to retire from the mining industry over the next decade, with less than 200 mining graduates per year nationally. Not just in the USA, this is a worldwide problem. In Canada the Mining Industry Human Resources Council (MIHRC), reported that older mining engineers are retiring early – at the age of 59.5 on average. It predicts that mining companies will need to hire 370 mining engineers by 2016 and 665 by 2021. The Minerals Council of Australia has predicted the need for an additional 86,000 mining professionals and skilled mine workers by 2020, and the Indian mining industry is also facing a shortage of between 2,500 to 3,000 engineers per year.

Jan 1, 2014

By Romel Villanueva, Juan Vasquez

We present the results of our field research on the variation of the density of the gassed explosives and their influence on the blasting results in the Peruvian mines: Yanacocha, Toquepala and Antamina. Currently, 90% of Peruvian mines uses gassed explosives, for their economic and technical benefits. But new practices and design criteria have had to be adopted, and the most important a careful control of the in-hole density, whose variation in the depth of the hole strongly affects the detonation process. For gassed explosives the density varies gradually according to the depth in the hole, due to the pressure on the bubbles by its own weight. The density at the bottom of the hole can reach critical values, which directly affects the start of the detonation in the booster zone with a high probability of nitrous fumes formation. On the other hand, density translates into the amount of explosive and energy available. Therefore, for the optimum performance of the explosive, the minimum and maximum values of the in-hole density must be determined. For the cases studied, the maximum in-hole density and the maximum charge length have been determined. When the charge length is greater than 7.0 m [ 23 ft.] special care must be taken with the cup density, which as a general rule should not exceed the value of 1.15 g/cm3 [71.8 lb/ft3] at the risk of losing the sensitivity at the bottom, also increasing the probability of nitrous fumes, bad fragmentation and finding intact explosive after blasting. In the large holes in Toquepala and Antamina mines, where the charge length can be greater than 9.0 m [29.53 ft]. If the cup density is greater than 1.15 g/cm3 [71.8 lb/ft3] the in-hole density can easily reach a high value of 1.30 g/cm3 [81.16 lb/ft3].

By Luis Huaroc, Augusto Sotomayor, Erick Rodriguez, Paulo Fernández, José Ricaldi, Luis Alejandro

The application of the Kuz-Ram model for the prediction of fragmentation is used worldwide, in Coimolache Mine it was used to determine blast domains and optimize the process by obtaining drilling patterns that meet a required X80 and reducing the uncertainty of drilling.

Feb 1, 2020

By Patrick D. McLaughlin, C Fordham

"The project outlined in the accompanying paper was to densify beach sands on the pond side ofa tailings dyke to the strength required for future dyke construction, This was to be achievedthrough the detonation of relatively small explosive charges in the sand to cause settlement intoa denser state."

Jan 1, 1992

By Juan Pablo Henríquez, Sebastian Lozano, Constanza Soto, Gonzalo Segura, Carlos Torres, Danko Morales

The Atacama Kozan underground mine, located in Tierra Amarilla, Atacama, Chile, was facing over-excavation and slow progress in drift construction, issues associated with the use of traditional explosive, ANFO. The presence of water in the blast holes required as well the use of cartridged emulsions, which extended loading times and increased operators’ effort. With loading times ranging around 76 minutes and lower advanced rate, Enaex Underground proposed the use of a pumpable emulsion-type explosive to optimize blasting, enhance safety, and streamline the operational process. This explosive is loading into the blasting holes using an UBT equipment (Unidad Bombeable para Túneles in spanish). This equipment allows mechanized loading, adaptation to small and medium diameter boreholes, ensuring compatibility with varying drilling profiles, integration with Atacama Kozan’s operational equipment and improvement in environmental and occupational conditions, with a measurable reduction in contaminant emissions and worker exposure risks. The implementation of this emulsion-based explosive allows an increase in productivity in drift development. A notable effective advance rate of 95% to 96% was achieved, alongside a reduction in overbreak in 7%, and a decrease in loading time to 40 minutes. Additionally, there was a 40% occurrence of drilling half cast, contributing to contour drift quality. The operation also benefited from a cleaner and safer working environment, enhancing operator ergonomics and reducing the need for jetanol and compressed air.

Jan 26, 2026