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The following situation was submitted as an ethics case study for inclusion in the Journal. To the best of our knowledge, they are based on actual circumstances encountered in the field. Blowing the Whistle Protecting Confidentiality or Doing the Right Thing? This case centers around a construction job and involves a contractor, subcontractor/blaster, and a farmer/homeowner who lives near the job site. It is essentially a study of professional ethics versus morality, our professional code of conduct versus what is right or wrong.

Jan 1, 2007

By Matias Suarez, Diego Zenteno

This paper is aimed to display the new advancements of blasting engineering done in different mining sites throughout the country, associated to electronic sequencing, energy of the explosive and its impact on the fragmented rock. This document explains how to define and implement selective sequencing in the blasting in order to promote the propagation of cracks, therefore impacting positively the productivity through the use of the LaGrange diagram. The LaGrange diagram is a very convenient and illustrative method to present the dynamic behavior associated with wave and crack propagation (Rossmanith. H, 2002).

Feb 1, 2020

By Travis Davidsavor, Stanley: Dong Vitton

Concrete is a common construction material used throughout the world, and with increasing demand of fast-track construction, blasting and concrete casting are occurring simultaneously at many sites where rock is being excavated for concrete placement. However, there has been significant disagreement in the construction industry as to what intensity of shock vibrations green, or fresh concrete can tolerate. Peak particle velocities are often arbitrarily chosen, or are simply based on materials such as plaster and drywall that have been more thoroughly studied in relation to damage. Previous research on green concrete has used the concrete’s static strength subjected to shockwaves at different ages as the primary damage criteria. In addition, the static strength tests have been based on curing time. However, changes in temperature or humidity can dramatically alter the hydration rate, which affects strength development of different cements. To account for temperature changes and humidity the concept of concrete maturity is commonly used and allows the researcher to see where the concrete was in terms of hydration progress. In general, static testing determines the failure stress that the concrete’s macrostructure can handle, and often failure occurs in the natural materials first or along large defects in casting techniques. Dynamic testing or high strain rate testing, on the other hand, loads materials at such a high rate that larger defects do not have time to react and instead the microstructure is more highly stressed leading to higher strength and stiffness values. This is known as the material’s strain rate sensitivity. Since dynamic testing better tests the microstructural strength, it is believed that it may provide a better way to assess damage to green concrete. Testing includes both static and dynamic compression as well as static and dynamic splitting tensile strength to assess whether damaged has occurred to the concrete. No significant statistical evidence was discovered that damage to the concrete occurred at five different “green” maturities from peak resultant velocities ranging from 10.66 in/s (271mm/s) to 4.40 in/s (112 mm/s) with average intensity of 6.7 in/s (170mm/s).

Jan 1, 2003

By Matias Suarez, Diego Zenteno

It is known that the introduction of electronic timing in the sequencing of blasting has changed the vision and way in which mining is developed. It is possible to deal with more complex and sophisticated drilling designs, without compromising productivity or safety. It has been shown in various studies, that a correct timing of the blasting provides an improvement in the improvement of the processes downstream, due to a decrease in the resistance of the resulting fragments coming from the interaction of the waves generated in the detonation of explosive loads. On the other hand, it has also been shown that variations in the composition of a same type of explosive, has a significant influence over the resistance of the blasted material, also the energy associated to break it, affecting directly its degree of fragmentation. This paper is aimed to display the new advancements of blasting engineering done in different mining sites throughout the country, associated to electronic sequencing, energy of the explosive and its impact on the fragmented rock. This document explains how to define and implement selective sequencing in the blasting in order to promote the propagation of cracks, therefore impacting positively the productivity through the use of the LaGrange diagram. The LaGrange diagram is a very convenient and illustrative method to present the dynamic behavior associated with wave and crack propagation (Rossmanith. H, 2002). This study focused on the methodology of the formation and measurement of seismic pulses, through the rock massif. For this purpose, seismic pulses were acquired in the field and then, the different dynamic phases of the wave were molded mathematically, with the purpose of favoring the coupling between them.

By Remi Proulx, Ruilin Yang

The effectiveness of presplit in soft or fractured ground is hard to visualize or quantify. There have been many attempts by the blasting community to measure and quantify the effectiveness of presplit blasts. Various methods have been adapted by different researchers, and the results are debatable.

Jan 1, 2019

By Matheson and Miller

Does anyone have any definitive information on vibration limits for damage to well casings near blasting? Also, are people using self-imposed limits when approaching cased wells? I can only tell you what I have personally done with success. Often in new construction in hard rock, the well is drilled before the foundation is excavated and before the ditch for the water line is excavated. These both require drilling and blasting. Under these circumstances when blasting for the ditch for the waterline we will drill right up to within 10 inches (not feet) of the well casing. We drill line holes the width of the ditch, then about a foot from this, another row of trim holes then as we move away from the casing holes for 1 1/4 inch stick powder for about three rows then as we get further still, we can load with ANFO. I do not have vibration data for this but my experience has been that as long as you are not displacing the material into the casing that no damage is done. These typically are steel casings for residential water service.

Jan 1, 2010

By Jose A. Sanchidrián, Ricardo Castedo, Pablo Segarra, Juan Navarro

A study conducted at a mine site that used traditional field surveying and physical hole spot markings bench marked their combined drill and blast performance. The analysis of the operational expenditure (OPEX) improvement determined there were many measurable cost improvements. A primary factor that most operations have to deal with is over drilling of holes. This alone impacts the cost due to nonproductive labor allocations, excessive explosive costs, increased drill tool costs, increased drilling costs and has an impact on the downstream operation cost such as digging the shot material. Other related investigations also show a downstream impact of poor fragmentation on digging payload tonnes, cycle times, haulage payload tonnes, time to load a truck and the number of passes to load the tuck. The intent of this presentation is to draw attention to aspects of mining we understand but may be missing the big picture effects, such as the ability to reduce the operational expenditures consistently to impact the bottom line. The target audience is across the board from owner operators, drill and blast contractors to blasting contractors. Everyone can benefit from these improvements.

Jan 1, 2019

By Robert Hopler

On June 13, 1912, the final decree of dissolution of the DuPont explosives trust was handed down, and the resulting new companies began operating at the beginning of the new year. The property assets granted to (or retained by) the companies were as follows:

Jan 1, 2014

By Alan Diaz Butron, Eng. Thierry Bernard

"In tunnel blasting the most challenging objective is definitively obtaining the maximum advanceassociated to a minimum overbreak. Achieving 100% of advance with no overbreak is the targetchallenge by Chavimochic Consortium. Chavimochic Special Project is an irrigation system that extends throughout much of the coast of the La Libertad Region, on the north coast of Peru. In 2012, it began management for construction of the third and last stage of CHAVIMOCHIC to irrigate lands of Chicama Valley, North of Trujillo. This project of 13 Km (8 mi) of various tunnels, it's a combination of technology and daily optimization by experienced people, which allow to accomplish the objective. Achieving this advance with no overbreak provide a huge saving on time. This paper describes the method, technology used, and the results obtained on more than 600 blasts done with conventional initiation system on the first 3 km (1.86 mi)."

Jan 1, 2017

By William Reisz

In our line of work,like many other professions, there may be times when circumstances or a series of events may arise, contributing toward unacceptable risk. When multiple parties are involved, there will almost inevitably be differences on how best to deal with these situations. Unless approached in an intelligent and these differences may often have the potential for costly and unexpected results.

Jan 1, 2014

By Laurence Neufville

Proper risk assessment and blast design are very desirable to the execution of a blast. Not only will this ensure that it achieves its desired outcome, but the probability of complaints and litigation will be reduced. Blasting engineers rely heavily on site-specific data for analysis and input to the blast design equations, and therefore data collection is critical to this process. The traditional approach to data collection is to carry out site-specific reconnaissance by visiting the site, but the time spent doing so can be reduced if a remote sensing approached is adopted.

Jan 1, 2009

By Lifeng Li, Jhon Silva-Castro

"Signature Hole Technique is one method to assess the vibration waveform of a production blast.Methematically, it is the convolution between a prior measured waveform of a single blast hole (signature) and a given time delay sequence (comb function). Being an advantage, the inverse operation of convolution, known as deconvolution, can be used to estimate the signature."

Jan 1, 2017

"Large scale open pit mining and quarrying operations dictate safe and reliable pit wall stability. The current approach of employing the particle velocity-scaled charge distance approach to estimate and minimize damage to residential structures is considered inadequate to protect rock slopes. This study utilizes close-in blasting vibration data as input to an advanced 2D numerical code to study its applicability to serve as a predictive tool in terms of blast-induced rock slope failure. Two tri-axial accelerometer stations, consisting of high-frequency and high-amplitude (20 kHz, 100g) sensors, located within ~100m of the blast, but at two different bench levels, were used to monitor a production blasting in a quarry. The production blast consisted of double-decked explosive loads in 155 mm (6 in) diameter holes, with an inter-deck delay of 42 ms, and each deck consisting of 130 kg (285 lb) of emulsionexplosive. The blasting vibration data obtained at the two bench levels were critically analyzed, and thevibration results served as input to the numerical model consisting of a single rock block with a 45 degree persistent joint plane but with specified strength properties, significantly different from that of the intact rock. The model was able to characterise progressive accumulation of damage in the form of micro-cracks along the joint surface as a function of the vibration load from successive explosive decks. The results showed that such a numerical model can serve as a very good diagnostic and predictive tool, when backed up by careful vibration monitoring and further supported by detailed slope monitoring."

Jan 1, 2017

By Javier Castaneda, Luis Zozaya, Noel Huarachi, María Rocha

The objective of the project was to implement and calibrate drill and blast models supported by Geotechnical and Geological models as well as the mine and operation characteristics. The models would then be migrated to HxGN Blast to ensure a productive process that is simplified, digitized and optimized.

Feb 1, 2020

By Santiago Gómez, Pablo Segarra, José A. Sanchidrián

In-hole detonation pressure measurements are unusual in the production environment of a mining operation, partly owing to the hostile conditions to which recording equipment and pertinent probes must be subjected and, partly by the constraints of the production cycle. In recent decades, detonation pressure measurement techniques have been developed using low carbon resistors (LCR)-based gauges. They are cheap, relatively easy-to-operate, robust and with a high percentage of success in both open-pit and underground mining. Detonation pressure measurements are extremely important when carrying out numerical modelling to simulate explosive induced vibrations, since simulation results are highly dependent on the pressure-time history applied on the blasthole wall. Analytical equations have typically been used to model the pressure-time history; however, they usually do not adequately represent the behaviour of the explosive in terms of: peak pressure reached, rise time, mean frequency, decay and shape of the signal. Experimental records may be directly used instead of utilizing synthetic signals if they are available. In this work, (LCR)-based gauges are used to measure detonation pressure inside a production blasthole. The operation principle of the gauges utilized and the instrumentation layout is described in detail. A flexible resolution USB oscilloscope with high sampling rate has been used to catch the elusive pressure peak event. Measurements were carried out in production blasts fired with ANFO (0.86 g/cm3) in an underground mine––this also includes velocity of detonation (VOD) records––. A procedure based on the shock impedance matching has been developed to calculate the detonation pressure due to the characteristics of the gauges prevent its direct measurement. Detonation pressures obtained range from 1.71 to 2.97 GPa (248.01 to 430.76 ksi) which are in line with pressures calculated from the VOD records. Mean frequency and rise time analysis shows that 2 of 3 signals cannot be described using typical analytical equations.

Feb 6, 2023

By Hairong Zeng, Shahram Tafazoli, Edmond Chow

Blast fragmentation is one of the main parameters for optimizing mineral processing, but reliable data is difficult to acquire, resulting in unpredictable performance and efficiency. Crusher and grinder circuits are designed to process specific rock size ranges. Oversized rocks require extra energy to reduce before feeding into the process, and undersized rocks indicate that the process is not used to its full extent. Blast design is the key to controlling the blast fragmentation, so the ability to accurately monitor the particle sizes is imperative.

Jan 1, 2011

By Ruilin Yang

This paper provides a theoretical analysis of shockwaves in an air-deck induced by detonation of an explosive charge and shows that the initial shock pressure in the air-deck at the interface with the explosive charge is only about 1% of the detonation pressure. A rarefaction wave with the low pressure travels back into the explosion detonation products greatly reducing the post-CJ detonation pressure. Additionally, AUTODYN modelling shows that the pressure attenuates further during shockwave propagation along the air-deck. Although the pressure increases at the bottom of the blasthole due to shock reflection, the overall pressure in an air-deck does not increase and is still around 1% of the detonation pressure which is too low to break most rock.

Jan 1, 2016

By Riaan Van Wyk, Gys Landman

In today’s mining environment the use of radio communications in the form of two-way radios, cellular phones and even automated mining, form a vital part of the daily operations of a mining site. The radio transmissions that are used are a form of energy and as with all other types of energy it can have an influence on blasting equipment.

Jan 1, 2011

By J. Silva, M. Kotraba, F. Pontanilla

Blasting is the application of highly complex science that, in some cases, could be viewed as an art. Many variables are involved in a blast, including geology, pattern design, timing and firing sequence, and explosives selection. Assuming that better results can be achieved by only increasing the powder factor is inaccurate. The Drill-to-Mill (D2M) concept has been in the mining industry for over two decades. The D2M approach is commonly viewed in an oversimplified manner, assuming that by simply increasing drilling and the amount of explosives used (both of which add operational costs), the downstream value will be created. An optimized D2M initiative should combine the smart application of explosives at the beginning of the mining process, matching the dynamic properties of the rock to the explosive selected to improve the efficiency of the energy created by the explosive to the rock mass being blasted, and to bring benefits to the mining operation across the entire mining and processing value-chain. This paper reviews the principles behind matching the shock impedance of the rock and the explosive and compares the traditional use of explosives versus the smart application for two hypothetical blasts.

Jan 1, 2024

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