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By Dennis J. Viscusi, James H. III Rowland, Lon D. Santis, Mark H. Weslowski

This paper describes the procedure for analysis of toxic fumes from the detonation of high explosives using the Large Chamber at the U.S. Bureau of Mines (USBM), Pittsburgh Research Center (PRC). This test is specified in 30 Code of Federal Regulations (CFR) Part 15.20 (g) as a requirement for the Mine Safety and Health Administration's (MSHA) approval of an explosive as permissible for use in underground coal mines. The Large Chamber replaced the Bichel gauge and CrawshawJones (C-J) apparatus in the 1989 revision of these regulations. To determine the safety of an explosive in terms of toxic gas production, the Large Chamber Test attempts to simulate mine conditions and miners' exposure to toxic gases from explosives.

Jan 1, 1995

By Tom Hale

Developers and blasters are faced with increasing public demand and regulatory restrictions to maintain the lowest possible levels of noise and vibration from blasting operations in populated urban areas. Pyrotechnic products have proven to be a low noise, low vibration alternative to conventional blasting for close-in rock excavation and concrete demolition applications. Pyrotechnic breaking charges often yield 1/10th the vibration and noise compared to traditional explosives, and have been demonstrated to increase public confidence and decreased damage potential where they have replaced explosives, thus allowing new opportunities for work and greater job profitability. This paper presents a practical approach to utilizing pyrotechnic products in various applications including trenching, mass excavation, demolition, and dimension stone production, providing methodology for pattern design, vibration probability and loading calculations. Field research data is reviewed and compared to conventional explosives.

Jan 1, 2008

By Dan McCutchen, Oettmeier

Kelly bar drilling and blasting is unique to Florida, the' Bahamas and other marine limestone areas in the world where blast holes are required but will not remain open for the loading of explosives. This type of rock formation usually yields 1.5 tons of recoverable rock compared to 2.2 tons per cubic yard for competent limestone. The loss of .7 tons per cubic yard is due to voids and sand in the formation. These deposits all contain water to the top of the blast holes which are collared only a few ft. above the ground water level. The working pit is a water filled lake which is excavated from the bank by draglines. These drills have been used in Florida for many years to depths of 65 ft or less.

Jan 1, 1991

By Virgil J. Stachura, Calvin L. Cumerlato

The U. S. Bureau of Mines is conducting research on blasting methods that reduce highwall overbreak and the associated rockfall hazards. This paper presents the results of tests using a low-density water gel to improve the quality of air-decked presplit blasts at a surface coal mine in New Mexico. The explosive's specific gravity averaged 0.50 and was bulk loaded using a modified truck which injected the gassing agent. Reductions in overbreak and resulting rockfall were achieved in comparison to a highwall presplit with ANFO. The test sections used 15° angled blast holes and resulted in 1,119 m (3,672 ft) of air deck presplit highwall using a low-density water gel which was then compared to 894 m (2,934 ft) of highwall shot with an ANFO air decked presplit design. The total quantity of explosives per hole ranged from 68 to 113 kg (150 to 250 lbs) and the 27 cm (10-5/8in) holes were 19- to 33-m (62- to 108-ft) deep on 5.5 m (18-ft) centers. Periodic visual examination and photographic surveys of the highwall test areas were used to document the amount of rockfall. In addition, laser profiles of selected sections were conducted to further delineate the damage and highwall contour differences.

Jan 1, 1995

By Piet Halliday, Ellina Kharatyan

Conventionally, emulsion matrices (unsensitized) need to be sensitized to become detonable explosives. This is done either chemically or mechanically. Both methods have their advantages and disadvantages. Mechanical sensitization involves the addition of microballoons (plastic or glass) to the emulsion matrix, in order to create hot spots during detonation. This is usually done at the manufacturing site and poses a safety risk in terms of the storage, transportation and handling of a 1.1 type explosive. Many countries throughout the world make use of chemical sensitization as opposed to mechanical sensitization as this allows for the storage, handling and transportation of two 5.1 type products rather than the 1.1 type explosive. Chemical sensitization involves the addition of a small amount of a chemical that reacts with a component of the emulsion matrix causing the formation of gas bubbles that act as hot spots during detonation. The disadvantage of this is the lack of accurate density control (due to various factors affecting the reaction) and the lack of comprehensive understanding of the operators of the reaction. This can easily result in poor blast performance. Due to these disadvantages a pumpable, non-detonable (5.1 type) mechanical sensitizer was researched and developed. This product allows for pumping at a 50:50 volume ratio with the emulsion matrix, when loading into blast holes. The significance of this is that a 1.1 type explosive is formed in the blast hole. As such, the security and logistical issues of the transportation and storage of the 1.1 type explosive are eliminated. Another advantage is accurate density control of the final product, specifically in small diameter long hole applications. A cost effective, unique mini pumping system has been developed for the loading of this product. Moreover, this system can easily be used for secondary blasting applications and the on-site packaging of cartridged explosive products.

Jan 1, 2015

By W. J. Birch

The dedicated documenting of blast design and vibration monitoring results forms part of the best practice methodology for today’s blasting operators. This allows regression curves to be constantly updated and in turn compatible charge weight determinations are based upon the most current data. The point can arise however when so much data becomes agglomerated that variations in blast design, geology or monitoring location response and their effects can pass unobserved and start to have an adverse effect on the forecasting capability of the regression due to a deterioration of the standard error statistic. The simple solution would be to only compile like-for-like blasting returns, but this prospect can quickly become unworkable due to the number of potential variables. In addition it is very difficult to spot subtle variations by simply examining a standard scaled-distance curve mainly due to the intrinsic data scatter that is always present together with the logarithmic nature of the regression curve. If indeed a variation is thought to be apparent, how can the degree and magnitude of its influence to be quantified? The Likelihood Ratio Test when applied to regression data can diagnose subtle variations between data sub-sets and provides a comparative statistic as to the degree of variation. By analysing datasets in such a way, levels of compatibility are obtained, indicating which sets can be combined in order to increase prediction capability.

Jan 1, 2004

By Luan Monteiro, Francisco Biulchi

The AngloGold Ashanti - Cuiaba mine sought innovative approaches to minimize lateral development and stope extraction time while maintaining optimal gold recovery and minimizing dilution. The stope 8GAL EXT 30 was selected as a case study. Traditionally, conventional blasting methods in such a scenario would necessitate either a single mass blast or slot development at each end of the stope. These methods typically compromise recovery and dilution or increase development time and risk. Additionally, conventional wired detonators require workers to re-enter the stope between blasts to load blastholes and connect detonators. The wireless initiation system offers a solution by initiating blastholes using magnetic induction signals that can penetrate rock, air, and water. This technology allows a pre-charged stope to be mined without requiring workers to re-enter the area between blasts to charge and connect blastholes. Engineers from Orica and AngloGold Ashanti designed a new extraction sequence utilizing the wireless initiation system. The process began with the opening of one end of the stope using a conventional slot and wired electronic detonators. Subsequently, pre-loaded rings were fired in three blasts to extract the opposite end and the intersection. The 8GAL EXT 30 stope was successfully mined using this technology enabled method. Each blast was meticulously monitored, and the stope void was scanned to assess blast performance. The results demonstrated a 4.6% improvement in recovery and a 16% reduction in dilution compared to the initial plan, and reduced exposure of people to hazardous locations in the stope. These results represent an additional value of USD 200k, gained from implementing wireless initiation to enable this particular blasting schedule.

Jan 21, 2025

By Ruilin Yang

The vector sum peak particle velocity (PPV) of blast vibrations describes the blast vibration intensity more completely than the PPV of a single component waveform. It is more logical to use a vector sum PPV as a vibration limit than using a single component PPV. In 1980 the USBM recommended the frequency related peak particle velocity criterion. So far this method has been only applied to single component waveforms, but not to the vector sum PPV since there is no method available to associate a frequency to the vector sum PPV. The present paper describes a method to define a principal frequency associated with vector sum PPV. The method is based on the weighted average of the principal (zero-crossing) frequencies of the three tri-axial components at the time of the PPV.

Jan 1, 2015

By Greg Rappard, Francois Holowenczak, James Rickard

The King George V (KGV) Shaft forms part of MTR Corporation Limited (MTRCL) Works Contract 703 extension of the underground West Island Line on Hong Kong Island. The Shaft and the associated adit was the sole access to excavate the running tunnels. Originally during the Detailed Design stage, it was concluded that blasting was not feasible at the KGV Shaft due to the close proximity of sensitive receivers in the form of residential buildings, electrical cables and hospitals. As a result, the Contractor planned to excavate the Shaft using mechanical means with a programme time of seven months. The Contractor appointed a Sub-contractor to analyse the feasibility of excavating the Shaft by blasting. The Sub-contractor reviewed the proposal and recommended the use of an innovative blasting technique that had never been previously employed in Hong Kong. The Sub-contractor recommended the Shaft be blasted using DetNet electronic delay detonator technology, manufactured by AEL Mining Services in South Africa, with an initial 1.5m depth of water ballast covering the blast face. The electronic delay detonators provided initiation accuracy to ensure there would be no overlap between sequentially detonating blastholes. The water ballast makes use of the effect of energy lost through the shock front causing the water to break up into droplets creating a spray dome resulting in the attenuation of the energy imparted into the surrounding rock mass. Various tests have demonstrated that both the maximum overpressure and impulse density are significantly reduced when water of a minimum depth is in direct contact with detonating explosives. This innovative blasting technique reduced the excavation programme by three months, saved HK$5 million in direct costs and totally mitigated the impacts on the public and other stakeholders nearby the KGV Shaft. Peak Particle Velocities (vibrations) rarely exceeded 2-3mm/sec (0.08-0.12in/sec) at a distance of 30-40m (98-131ft) from the blast location and air overpressure levels were reduced below the Hong Kong target level of 120dBL. In total, 24 blasts were fired with an average advance of 1.6m (5.25ft) with an average powder factor of 2.03kg/m3 (0.127lb/ft3) to 1.84 kg/m3 (0.114lb/ft3). The initiation pattern had 5ms between sequentially detonating blastholes and 20ms between adjoining rings.

Jan 1, 2013

By Clara Godoy, Paulo Couceiro, Juan Navarro

The continuous automatization and digitalization of the different stages involved in any underground construction bring new possibilities to optimize the operation. One of the most important requirements for the development of these projects consist of a proper rock mass characterization for optimizing the stages of the drilling, blasting and support cycle. In the last few years the road to digitalization has gone through data science and big data, showing the importance of data gathered to describe the geological and geotechnical environment that surrounds the operations. Since rock characteristics have an important influence in the drilling response, the technological advances in the sensorization of drilling machinery such as the Measurement While Drilling system (MWD) allow to gather the necessary amount of information to be applied in data science processes to evaluate changes in the rock mass with higher resolution than conventional methods. In this paper, Machine Learning techniques have been used to combine data monitored from the drill rigwith scanner profiles of the excavated sections to develop an automatic geotechnical rock mass characterization model able to estimate potential zones of over- or under-break of the remaining rock mass in underground blasting. By comparison of scanner profiles of the excavated sections with the blasthole positions, an Excavated Mean Distance (EMD) between the contour blastholes and the excavated profile has been obtained, which may be considered as damage measure. Considering blasting factors as constant, the model combines the rotary, percussive, hydraulic flushing and the rate of advance of the drilling, and the confinement of the rock mass by depth, to detect zones with different rock properties. This provide an early information of the rock mass condition around the blastholes and the prediction of expected overbreak generated after blasting, being possible to design more efficient bastings, in which each borehole is filled with the right and necessary explosive charge. The analysis comprises data from 57 blasts (around 1700 contour blastholes) and more than 4000 excavated sections.

By Clara Godoy, J. A. Sanchidrian

In this paper, Machine Learning techniques have been used to combine data monitored from the drill rig with scanner profiles of the excavated sections to develop an automatic geotechnical rock mass characterization model able to estimate potential zones of over- or under-break of the remaining rock mass in underground blasting. By comparison of scanner profiles of the excavated sections with the blasthole positions, an Excavated Mean Distance (EMD) between the contour blastholes and the excavated profile has been obtained, which may be considered as damage measure.

Feb 1, 2020

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 John Arrell, James Stuart

We have developed a tester that is uniquely able to measure the no-fire power level of certain types of electro explosive devices (EEDs). In the past, it has been difficult to establish a no-fire power level for nonlinear conductors, such as semiconductor-bridge (SCB) EEDs, and conductive-mix EEDs.

Jan 1, 2011

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 Charles E. Van Barneveld

RBH Note: the following item is a little different than the usual, in that it shows how explosives were used in the past to assist in putting down holes for iron ore prospecting on the early Mesabi Range of Minnesota. The way explosives were used would not even occur to the modern explorationist, given the equipment available today. The reason for the great difficulty in putting down a hole was that the area was covered with debris from the great glaciers of the past (the same ones that carved out the Great lakes). This debris consisted of boulders, clay, sand, and any other imaginable mixture of materials.

Jan 1, 2013

By Jair Koppe

The unsatisfactory blasting effect is mainly related to the improper selection of design parameters of drilling and blasting scheme. In order to evaluate the rationality of drilling and blasting scheme, scientifically, this paper brings forward a method for scientific evaluation of blasting scheme. This method evaluates the blasting scheme by observing the accuracy of drilling, explosive density, charge, lumpiness analysis, filling length, slope surface design, floor level, vibration monitoring and flyrock. The evaluation involves different stages of blasting construction and implementation, such as terrain survey, drilling, charging, environmental impact and safety evaluation. Through this method, several key problems for improving blasting scheme design can be determined by analyzing each parameter. This method improves the key parameters of blasting design by analyzing blasting results and establishes the relationship between blasting effect and technical design.

Feb 6, 2023

By Paul Worsey, Braden Lusk

Differences exist between public perception of construction blasting and quarry blasting. In general, people are able to tolerate short term inconveniences much better than long term ones. The paper focuses on the public perception of quarry blasting in St. Charles County, MO. This expanding urban environment has seen new legislation targeting preexisting quarry operations that have been in place for many years. A survey was made comprising interviews conducted to gauge perceptions of persons with varying demographics. Interviews covered topics involved with quarry blasting and its reporting methods. The purpose of the interviews was to determine public perception of blasting and how best to report results of vibration measurements. The use of different, less technically complicated measurement scales for vibration and airblast was considered as an alternative reporting system. The question for the industry is, “Has our past haste in adopting complex scientific scales and units been detrimental to us?” In other words, are we reporting the correct things? For airblast, the decibel scale was evaluated against millibar in the public eye. Peak Particle Velocity was also compared to that for displacement. Current legislation in the county is based on complaint levels rather than damage criteria. The complaints most likely not only come from ignorance to the affects of blasting on structures, but also sparse understanding of the units used to report these affects. The past practice of treading softly as an industry has been proven to be a poor choice, and education of the public as well as lawmakers on all levels is necessary. The Mississippi Valley Chapter of ISEE has begun to conduct seminars to this end. One educational seminar has taken place for officials and lawmakers in the St. Louis area, and others are in the planning stages. The focus of this paper is to gauge perception of the damage criteria reported today, and locate focal points for future education of the public in rapidly expanding suburban environments.

Jan 1, 2005

By John Hutchings

Drilling and blasting is a clearly delineated work process, which has well defined inputs and outputs. Drilling and blasting is also a process with a number of steps each of which has measurable outcomes. Drilling and blasting is ideally suited to the application of Total Quality Management principles. Most drilling and blasting information is generally poorly managed with disjointed and unrelated Information Technology systems managing parts drilling and blasting data. Data is often moved from on system to another, sometimes manually. In the field, drilling and blasting is still very much a paper based system and which has not generally benefited from some of the recent hardware and software technology advancements now “on the shelf”. Data collected on paper rarely is transcribed back into an electronic system for further analysis. It is often difficult to collate or review historic drilling and blasting data. This paper will present a definition of Total Quality Management and demonstrate how it can be applied to the drilling and blasting work process. Total Quality Management defines the mechanisms for the application of continuous improvement to drilling and blasting. Continuous improvement will provide opportunities to modify drilling and blasting work process outcomes and generate real cost benefits within the overall mining process. A complete drilling and blasting management system frame work, called DBS, is presented in this paper. DBS provides all the components necessary to implement a full drilling and blasting Total Quality Management solution. Also highlighted will be appropriate “off the shelf” technology that can be applied to replace current paper based systems and provide the means to connect with other mine data systems. Various examples will be discussed which will demonstrate potential benefits of applying a structured Total Quality Management approach to a drilling and blasting work process.

Jan 1, 2004

By Todd B. Harrington, Dennis M. Lydon, Walter B. Sudweeks

Heavy ANFO products made by mixing ANFO (or AN prills) with a relatively small amount of emulsion (typically 15-30 percent) have become very popular in recent years. They are less expensive than straight, sensitized emulsion and maintain the good shooting characteristics of ANFO but have higher bulk strengths. Their use, however, is generally limited to larger diameter, dry boreholes. Smaller diameter, wet-hole quarries have not been able to widely utilize this low cost bulk product.

Jan 1, 1989

By Wm. Reisz, Raphael Trousselle

We are now well into our second decade of commercially available electronic initiation systems. Over this time, the technological advances have made electronic systems a very practical option for a wide variety of blasting applications.

Jan 1, 2011