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By Jody Todd, Ernesto Villaescusa, Ronald Lachenicht, Kelly Fleetwood

In the underground environment, characterisation of a rock mass during the mining cycle becomes increasingly difficult due to a lack of rock mass exposure for measurement or observation. In most cases rock mass characterisation occurs prior to mining by inspection and logging of exploration drill core, or prior to mass excavation through drive mapping for geological and geotechnical data. Characterisation strategies, if applied during the mining cycle, can reveal near-field anisotropies that may affect the behaviour of the rock mass with respect to excavation. These methods can aid in understanding the performance of stopes based on geometry, in-stope extraction sequence, and stress modelling. One such method of characterisation involves the use of production blast vibration monitoring and analysis as indicators of rock mass anisotropy through travel-time tomography.

Jan 1, 2008

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 Jorge Cardenas, Diego Sanchez

Maximizing SAG mill throughput and metallurgical recovery in hard rock operations requires achieving target fragmentation, particularly a sufficient proportion of fines (<25.4 mm). These fines thresholds are strongly influenced by rock mass competency, commonly characterized using the Axb parameter (30–70) from the JK Drop Weight Test. In many operations, conventional blasting designs and standard emulsions fail to generate the fines content required for efficient downstream comminution. This study evaluates several advanced blasting strategies aimed at enhancing fines generation in very competent rock masses while maintaining cost-effective drill and blast performance. The first approach focuses on steadily increasing the powder factor (kg/t) as a core strategy, complemented by adjustments in blasthole diameter, reduced burden and spacing, the use of dual initiation points, short inter-hole delays (<25 ms), and optimized sequencing—all aimed at enhancing energy distribution and maximizing fines generation in highly competent rock masses. The second strategy consists of increasing the energy factor (kJ/t) by selecting explosives with higher energetic content and detonation performance. This includes the use of heavy ANFO blends and ultra high-energy emulsions with aluminum-based formulations, achieving Relative Bulk Strength (RBS) values between 180–190 and up to 210–230, respectively. These products offer higher detonation velocity (VOD) and peak pressure, enhancing shock energy transmission and breakage efficiency. Field results in granodioritic porphyries with high uniaxial compressive strength showed a 3–5% increase in fines generation compared to standard emulsions—contributing directly to meeting mill performance targets in high Axb conditions. Combined, these strategies provide a practical and technically validated pathway to achieving fines generation targets required for optimal mill performance. When matched to site-specific rock mass characteristics and integrated with blast monitoring tools, they enable improved fragmentation control, reduced P80, and enhanced plant throughput—without compromising operational efficiency or increasing costs disproportionately

Jan 26, 2026

By Michael Burrell

This project involved the protection of an historic landfill located on the site. Construction blasting was for a permanent access road to carry traffic to and from a new metal processing plant being constructed nearby. The landfill contained materials disposed of during the closure of a Phosphorus plant that had previously occupied a portion of this site.

Jan 1, 2012

By Francisco Sena Leite, Vincius Miranda, PhD Machado Leite, PhD Pinto, Raquel Carvalhinha, Alexandre Julio, Dorival de Carvalho

Rock blasting, in particularly the drilling process, is one of the first processes in the stage of rock fragmentation and plays a fundamental role by influencing all the following stages. Given its importance, some proposals to optimize this process have been presented over the last few years. These proposals, while having different approaches, aim (in a large part) to minimize the costs of drilling and blasting respecting the limits of fragmentation required by primary crushing. Reviewing some recent articles leads us to an enriching experience, since the authors of these articles clearly model the problem, but do not address the mathematical solution of these models, which in turn, given their non-linear nature, have no directly and easy solution. Simple and even robust optimizers present in the market show different results and often do not converge to a single solution. To address this problem, an adapted gradient heuristicbased model was developed to try to find optimum values. Heuristics search for values of stemming, subdrilling, burden and spacing that minimize the costs of blasting and drilling. This search, which by the nature of the heuristic moves the solution in the direction of the gradient with maximum decrease to find optimal solution, found values that in turn, when compared with values presented by market solutions not only equaled them as, in some situations, even improved the proposed solution. The algorithm was tested and validated on the field, and although the results have already been presented in papers published in the last year by the authors of this paper, it is now presented with its mathematical formulation and comparison with the other solutions. This approach is expected to be able to improve (and even demystify) the process of pattern expansion and be the basis for future work in the continuation of the optimization process.

Jan 1, 2019

By John L. Didlinger

We all hate the paper work in keeping accurate blasting records. Nevertheless, have you ever thought what those records could show you? Think about it. Those records could show you vibrations, noise, and safety problems. They could show you the ratio of powder used and tons produced, the cost per foot, even help negotiations for pricing.

Jan 1, 1997

By Alton Dunaway, Kevin Sullivan, Charles Gray, Doug Hall, Kevin Grant, Kelly Thiel, John Paulson, Bruce Leland, Cole Boyd

Beaver (Castor canadensis) are responsible for economic losses exceeding $4 billion over the last 4 decades in the southeastern United States alone. A large portion of these damages occurs to public roads and highways, forests, agricultural resources, and other property from flooding caused by beaver dams. The United States Department of agriculture, Animal Plant Health Inspection Service, Wildlife Services (WS) program is a non-regulatory Federal program directed by Congress to assist resource owners with managing damage caused by wildlife.

Jan 1, 2007

By Jorge Flores, Dean Nichols

Some view quantitative risk assessment (QRA) as difficult to understand and complicated to use. They are comfortable with the proven reliability of quantity distance (QD) and question the benefits of applying QRA principles to explosive safety. In response to such questions, a review of the history of the American Table of Distances (ATD) provides insight to the strengths and weaknesses of the concepts behind QD tables. Additionally, a closer look at QRA features that are available today will reveal stunning capabilities and improved user friendliness not available previously. This paper looks at the early days of explosive safety, the use and limitations of QD, the meaning of risk in the context of QRA and discusses recent developments that knock down barriers previously hindering acceptance of QRA among regulatory agencies.

Jan 1, 2015

By Matthew K. Coy, Paul N. Worsey

The work described in this paper comprised the master’s thesis work of the primary author and was conducted at the Missouri S&T experimental mine. The objective was to determine if rubber tractor treads could be used as an alternative material for blasting mats. These treads are made from steel cable and vulcanized rubber and are very tough. However, once they reach the end of their life on mobile equipment, they are destined for a landfill, or dump site, because they are too tough to recycle. A potential alternative use for them is as blasting mats. Several discarded treads were obtained from Kolb Grading in St. Louis.

Jan 1, 2015

By Zhao Jie, Christopher G. Smith

Commercial explosive use in China has been dominated by powdered AN-TNT mixes. Water gels and emulsions are now gaining market acceptance because they offer potential for better performance. Although raw material costs for emulsions initially may be more than AN-TNT mixes, the more expensive technology improves sensitization and leads to lower costs overall for mining operations. A recently completed study in northeast China compared microsphere-modified emulsions to AN-TNT and lower-cost emulsions. Testing of microsphere-modified emulsions at several pH levels indicated a high degree of stability and consistency of VOD. Using 42 mm blastholes in underground mines and 170 mm holes in sandstone open pit mining demonstrated the superior performance of glass microsphere sensitized emulsions. Comparisons of explosive cost, drilling cost, secondary blasting cost and muck pile profile were favorable to the microspheres-sensitized-emulsions. Noxious fumes with AN-TNT or with water-based systems that partially fail during detonation are also a concern. Efficient detonation of emulsion products sensitized with hollow spheres appears to reduce fume generation. Prolonged storage or exposure to water also is not a problem.

Jan 1, 1997

By Thomas P. Dowling

Historically, laws controlling the manufacture, sale, transportation and storage of high explosives and regulations governing the use of explosives were formulated to prevent accidents or eliminate incidents that might jeopardize public safety. Many of the original laws and regulations regarding classification of explosives and blasting materials, tables of distances for separation and/or isolation of explosives, construction of storage magazines and methods of blasting were based upon empirical data, field experiments or scientific facts. During the past few years, however, it appears that some of the explosive laws and blasting regulations introduced and/or enacted by federal, state and local agencies seem to be based more on political expediency than on factual information or technical data.

Jan 1, 1976

By Sean Paterson

The purpose of this paper is to demonstrate a method of delaying and loading a shot. Since entering the construction industry, I have learned that cover is needed on a lot of blasts. When in close having to cover shots was new to me and it seemed time consuming and wastefull. Until I really needed it and didn’t have it. So What To Do??? Remember that safety comes first, if you have concerns cover it. Even if you have to sit on your shot all night to wait for cover. This method is not a replacement for cover, but it will help keep your rock down. Do not bet your life, others lives or your career on it.

Jan 1, 2001

By Klaus G. Hinzen

Seismic observations offer the only possibility for remote sensing of physical processes like shock-front spreading, material crushing and ground movement. A better understanding of these processes will help to increase the economy of blasting. We developed a digital seismic monitoring system for research purposes. The system can simultaneously record up to 64 channels with a maximum sampling rate of 31 kHz per channel. A software package for rigorous analysis of blast induced seismic waves has been developed.

Jan 1, 1989

By Doug Johnson

This paper reviews the field implementation of R & F Coal's blasting optimization work concerning analysis, prediction, and control of overburden blasting vibrations using site specific measurements and state-of-the-art computer technology. Blasting personnel at R & F Coal had the opportunity to work jointly with Otto Crenwelge of Shell Development Company in his test studies and to later be instructed in the procedures involved in optimizing vibration frequency.

Jan 1, 1988

By D E. Shaw, J B. Case, J Gusek

Explosive casting of overburden is defined as the use of explosives in blasting to move overburden to a spoil pile without rehandling. Studies of the economic feasibility of the method, and the formulation of a design hypothesis involving rock properties, and blasthole geometry are presented. These studies indicate that if technical feasibility can be demonstrated to increase surface coal production, considerable economic advantage would accrue to coal mine operators.

Jan 1, 1980

By Joe Atalla, Jesse Desrochers, Rodrigo Hayashida, Joseph Mukendi Kabuya

The Mont-Wright mine stands as a prominent open-pit operation in Canada, renowned for its vast iron-ore reserves. However, the efficacy of its blasting operations, crucial for efficient production, has encountered challenges due to the diverse lithological compositions across multiple pits. This study presents a comprehensive approach to optimize blasting practices at Mont-Wright mine, tailored to the specific lithological characteristics of each rock domain. Through systematic analysis and experimentation, blasting guidelines were meticulously developed, aiming to enhance grindability and equipment productivity. The implementation of these guidelines promises significant improvements in operational efficiency and resource utilization, positioning Mont-Wright mine at the forefront of sustainable iron-ore extraction.

Jan 21, 2025

By Cary Moffat, John Kita, Rick Walker

The Lac des Iles Mine, in an isolated area of NorthwesternOntario is a relatively new open pit platinum and palladium mine. They were encountering problems with the equipment and production scheduling when ramping down to begin production on the subsequent benches. A co-operative effort between Lac des Iles Mine operation people, ICI Explosives, and the mines drilling and blasting contractor - Consbec Inc., resulted in a decision being made to use full depth sinking cuts to provide access to the next bench.

Jan 1, 1996

By Ewan Selers, Gary Cavanough

Drilling automation technology is well advanced and automated drill rigs are in use at a number of operating mines. This is not the case for the other drill and blast processes due to significant technical challenges to overcome. These challenges, with regard to the current “on bench” practices, include placing the initiators, loading the explosive and connecting up the initiation system. Although difficult, these challenges will be solved with engineering advances.

Jan 1, 2016

By Scott G. Giltner, Terry Millar, Ben Bringhurst

"Kennecott Utah Copper (KUC) Smelter scheduled a rebuild of their flash smelting furnace forSeptember, 2014. KUC’s goal in this project was to reduce the rebuild time from 65 to 55 days by using explosives to break the matte and brick layers of the uptake shaft and hearth sections of the furnace. Previous rebuilds had employed the slower technique of mechanical breakers to remove the matte and brick layers which took 22 days. KUC has many years of experience in removing slag from the uptake shaft, but they had never used explosives to remove the hearth. As far as KUC was aware, no other smelter operation had attempted a hearth removal in this way."

Jan 1, 2016

By Ron Woolf, Corry Goumans

This paper describes rock slope remediation performed along America’s first Superhighway, the Pennsylvania Turnpike and in particular, the specialized drilling equipment designed and built by Pacific Blasting to complete this work. This S-month project was performed on an existing rock cut slope within the Bedford Narrows, a gap formed by the Juniata River through Evitts Mountain. These rocks are in the folded Juniata and Tuscarora Formations within the Valley and Ridge Province and strike northeast with near vertical to slightly overturned bedding.

Jan 1, 2001