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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

By Tristan Worsey, Jhon Silva

The paper discusses a limestone quarry case study that looks at change in fragmentation due to using different charge sequences when using the regular rhythmic timing method.

Feb 1, 2020

By Scott Scovira

All flyrock incidents have the potential to result in injuries or fatalities that can result in loss of company reputation, license to operate with clients, and bear the exposure to high cost liability. From 2007 to 2009, one NA Quarry and Construction Business experienced a series of flyrock incidents. In the Spring of 2009, this business declared that the frequency and severity of Flyrock Incidents had reached an unacceptable level. A Flyrock Elimination Program was launched.

Jan 1, 2012

By Lazar Kricak, Vladislav Kecojevic, Dragan Bogunovic

In spite of many advantages explosives have, their usage may cause environmental problem such as seismic vibration. One of the solutions to this particular problem may be application of an artificial screen as a barrier to the seismic wave path. This paper presents the results of experimental research on the artificial screen concept, its characteristics and role in attenuation of seismic effects generated by blasting. More than 1,500 laboratory measurements were conducted with different combinations of screen sizes, positions of the screen to blasting source, and intensities of blasting impulses. The results of the study show a significant reduction of generated vibrations by employment of artificial screens.

Jan 1, 2007

By Chris Breeds, Larry Leone, Jerry Wallace

One of the Authors was recently retained to provide a professional engineering analysis of the potential impacts from underwater blasts used to enlarge intake tunnels at the Cheesman Dam near Denver in Colorado and to design Blast Protection Bags that could be installed in each tunnel to protect the 100- year old downstream valve structures.

Jan 1, 2012

By Yong Pan, Purushotham Tukkaraja

It has been well understood that blasting is the cost-effective method for breaking rocks as compared with the mechanical systems. However, vibrations induced by blasting in open-pit mines could pose problems to the structures surrounding the mine site. Blast-induced ground vibration has been the subject of research for several studies in the past; because of the complex nature of blasting mechanism, it is difficult to predict blast-induced vibrations. Even though there are several approaches proposed by the previous researchers, traditional regression analysis is still playing an important role in predicting blast-inducedgroundvibrations.

Jan 1, 2019

By Glenn Tobin

The overarching goal in modern drill and blasting operations is that of optimising mining operations to achieve higher levels of productivity, safety, profitability and sustainability. Air decking, a technique used in drill & blasting to optimise explosive product use while achieving a target rock fragmentation1, is a technique that when executed correctly is proven to achieve consistent results independent of rock strength and the position of the holes (single, multiple, vertical, slanted), as well as being proven to reduce super-fragmentation (under-size or fines) while able to achieve optimal fragmentation, especially in the stemming zone2. The ‘shock absorber effect’ if the air deck reduces ground vibration and air blast3. Additionally, the practice of loading explosive product directly in saturated ground without dewatering or lining prior is an increasing global trend.

Jan 1, 2012

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 Brent Blanchard

As most veterans of our industry are aware, explosive demolition by its very nature is often a challenging proposition. Even under the best of circumstances, proper planning and care must be taken during a variety of processes to ensure a safe, successful result. However, every now and then a project suddenly arises where safety, timing and cost factors combine to form a critical scenario requiring rapid execution in an environment far more challenging than the norm. On these occasions, the stresses, complications - and most notably the dangers - related to the industry increase exponentially, and conspire to test the mettle of even the most seasoned experts.

Jan 1, 2003

By Italo Onederra, Miguel Araos

"Most of the current explosives for mining blasting activities are based on ammonium nitrate (ANFO, emulsions and watergels). AN-based explosives’ detonating properties were discovered in the 50’s and since then they have proven to be reliable, safe and cost effective. However, there is no current alternative raw material to replace AN. As part of a program of research initially funded by the Australian Coal Association Research Program (ACARP), Mining3 and the University of Queensland engaged in the search for potential oxidizing agent alternatives that could replace AN in the manufacture of mining explosives. Candidates included those that are produced in large quantities and that can be cost competitive with ammonium nitrate. The initial work identified hydrogen peroxide (HP), calcium ammonium nitrate (CAN) and sodium nitrate (SN). Explosives mixtures were prepared and sensitized using void sensitization techniques. The detonation properties results showed that explosives based onmixtures of HP/CN and HP/SN as the oxidizer were able to detonate in a range of 2000 – 5000 m/s, indiameters 50 and 102 mm, and densities in the range of 0.50 – 1.40 g/ml. Although more studies need to be conducted to fully understand these explosives, if successful, these explosives would be able to offer an alternative to the AN-based explosives in the mining industry."

Jan 1, 2017

By Thomas L. Barkley

This paper describes an unusual design for a 12 foot diameter, 30 foot deep circular shaft shot in a close in urban environment less than 100 feet from occupied structures. It uses diagrams, video footage, and vibration results to describe a 3 deck, 17 hole burn round used to pull 17 feet in one lift.

Jan 1, 1994

By Alain Blanchier, Anne Charline Sauvage

Rock mass variations have a huge influence on explosives efficiency and on blasting results. Numerous blasting improvements could be gained by taking into account rock mass and its variations. However, extracted rock mass is generally considered as statistically homogenous. The development of a panel of pre-blast survey procedures that every blaster can use, consists in the realization of a process integrated into every day work: for example as well as toe burden or blast hole depth, discontinuities spacing or the weathering expanse have to enter in rule book, if it provides blasting efficiency and security improvements.

Jan 1, 2004

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 Joseph Indeck, Seokbin Lim, Andrew Thompson

In the design of explosively driven penetration devices, understanding the impact conditions between the explosively propelled penetrator and the target is one of the most important steps in optimizing the performance of the device. These impact conditions are especially prevalent when a shaped charge jet impacts concrete, which is not an ideal target material. The specific impact conditions, including but not limited to the impact angle and jet properties, create a great deal of variability that affects the performance and penetration of the shaped charge. The large amount of impurities and voids in concrete, along with its heterogeneous nature and the general strength characteristics, make concrete a non-ideal material for shaped charge jet penetration. These material characteristics lead to a highly non-linear deformation behavior of the concrete target during a hyper-velocity impact.

Jan 1, 2011

By Jeff Yaro, Steven P. Case, Carl Kish

This project involved the construction of a new 4-story library on the campus of Cornell University in Ithaca, New York. The new building was constructed completely below grade, adjoining several of the oldest buildings on the campus. Excepting some surface soil, the job was 100% rock and the excavation had to be completed within a 3-month window.

Jan 1, 1992

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan

In the bench blasting, the realisation of an economic, and safe blasting is only possible with a reliable blasting design on condition that considering all sequential activities such as drillingblasting, excavation-loading, haulage, crushing (especially primer crushing). Here what we mean with a good, and reliable design is that ensures an almost displaced, adequately swelled muckpile with desired fragmentation degree for the loaders effectivity, and succesive usage. Meanwhile it must also has no environmental problems such as ground vibration, air blast, and rock flyings, or at least these matters have to be minimised. Two main parameters which have generally being questioned to achieve a safe and economic design on any rock conditions, are specific charge, and burden. In the condition of determining these elements, the other blasting parameters could be calculated according to them, and the blasting design could be completed. Within the scope of this study, it was aimed to determine the optimal blasting conditions of gypsum which is major rock unit of overburden at Sivas Celestine open pit mine. First of all, the engineering (mass, and material) and digging difficulty classifications of gypsum were done according to the current classification systems by using the results of field and laboratory studies. Then the blasting system which was being used on all rock units, was considered, and the necessary data were obtained. After previewing the site properties, predesigns were done, and applied by adopting Langefors design model. The necessary adjustments were done before, during, and after the shots, and the applications were observed. In order to determine, and record the data from each shots properly, a practical form was developed, and all data were transfered to these forms which give information about the blasting results such as muckpile displacement, and height, average particle size, back break, and rock fly existence, number of boulders etc. The blasting parameters such as burden, hole diameter, hole inclination, the amount and position of primers, bench height, delay sequence, and blasting geometry were considered for the iteration of each shots. During the applications, ANFO, gelatine dynamite, and electric delay detonators were used as explosives.

Jan 1, 2004

By David La Rosa, Matthew Craft, Lee Julian

Rules of thumb are ubiquitous in blasting. Typically presented as ratios, they assist with the initial assumptions of blast design and provide guidance for best practice. Examples include the blast hole diameter as a function of bench height, and stemming length as a function of hole diameter. The most common rules of thumb were developed in mid-20th century and it is important for a blaster to know if the rules of thumb are still reliable.

Feb 6, 2023

By Stephen Mansfield, Saran Sankar

The Sentinel open pit copper mine, operated by First Quantum Minerals Ltd, is located in the North West province of Zambia. The Sentinel orebody is a sediment-hosted, structurally modified deposit in which mineralisation is contained in the phyllite formation, which occurs as a series of layered, continuous sheets having a northerly 20 to 30⁰ dip. The persistent nature of the geological structure can lead to the generation of large slabs when joints are relatively close together or very large blocks when joints are more widely spaced. With standard blasting methodologies, the challenging fragmentation most commonly occurs in the stemming zone and blast interfaces, reducing excavation rates and increasing the risk of crusher bridging events and reduced throughput. A generalised approach to increase powder factor would increase in drill and blast costs and would not be sufficient to target the specific cause of the challenging fragmentation. Implementing differential blast energy based on post blast requirements for different material type, such as ore and waste, and rock mass characteristics is not new in the mining industry. High-energy blasts for ore aim to produce finer materials, enhancing downstream processes such as crushing and grinding, while reducing power consumption and increasing throughput. Conversely, waste rock often requires less energy in order to deliver optimised fragmentation for loading and hauling efficiency. Identifying and applying optimum blast energy to specific material type and geological domains will not only ensure smoother and efficient operations throughout downstream processes, but will have a direct impact on overall profitability of the entire operation. This paper will describe the methods used to model and implement differential blasting across a range of material types in order to deliver the required blast outcomes for ore and waste and the impact on downstream processes and drill and blast unit cost.

Jan 21, 2025

By Lon Santis, Michael Swisdak, John Tatom

The Institute of Makers of Explosives (IME) and A-P-T Research, Inc. (APT) have developed a quantitative risk assessment tool called IMESAFR (IME Safety Analysis for Risk) for managing risk from various activities undertaken in the commercial explosives industry. The first version was completed in 2006 and Version 2.0 of the software was completed in 2012, incorporating several major new features. The platform is now based on a Geographic Information System (GIS), providing a bird’s-eye-view to help visualize facility layouts and risk. Spatial data on potential explosion sites and exposed sites can now be automatically transferred from the images to ease users’ data input. Use of GIS data provides the ability to check facility compliance with quantity-distance (QD) standards such as the American Table of Distances (used by the Bureau of Alcohol, Tobacco, Firearms and Explosives, ATF), the NATO standard (used by Natural Resources Canada and other nations), or a user-defined table. Research conducted and knowledge gained over the last 10 years enabled changes in the algorithms and models that provide greater fidelity and reduce conservatism. Expert users can change global settings to more accurately match actual site conditions and the program runs using either Imperial (English) or SI (metric) units of measure. These changes and other new features are discussed and demonstrated.

Jan 1, 2013

By Jack Eloranta

This paper compares energy requirements for blasting, crushing and grinding. By tracking electrical consumption for various powder factors, a general trend has appeared. This study involves over 100 million tons of ore and powder factors ranging from .5 lbs/LT to .8 lbs/LT. Actual energy usage is compared to predicted energy based on the Bond equation.

Jan 1, 1997