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By Gary Kahn

In this document the VODR is discussed from a technical point of view and is intended to give the reader a feel for the design of the instrument, its technical specifications, and its limitations. It is not intended as a tutorial on the use of the instrument in the field.

Jan 1, 1989

By Jerry Wallace

A highway bridge demolition project to allow shipping access to a new container port in Puget Sound ran into trouble when contract-stipulated mechanical means of demolition failed. Blasting was then employed under less than ideal conditions and was successful.

Jan 1, 1999

By Christopher Jon Preston, Troy Williams, Daniel Roy

There has been significant progress made with narrow vein gold mines in which a second option for crushing has begun to attract attention. To ensure the profitability of a mine that has based its economics on the absence of a crusher station, more than just best blasting practices are required. Using a blasting operation itself as a primary crusher would undoubtedly save enormous capital costs as well as eliminate some of the costs of crushing ore with the result that considerable savings might be realized. The challenge would be to define the conditions necessary to make this type of operation feasible by providing consistent blasting methods that result in a significant paradigm shift with respect to both blasting and current underground crushing methods. A break model has been developed and applied as a technique in designing blasting patterns based on a unit charge blasting geometry and stress reflection from free faces. There are four components to this model and these are 1) unit charge, 2) thermodynamic/energy, 3) stress reflection, and 4) radial break. Some important changes in timing between holes and rows based on rock properties and the percentage of burden moved were also used. On-site testing at a narrow vein gold mine in Quebec Canada, provided measured parameters for the model. No underground crusher was planned - relying only on the fragmentation profile generated by ring blasting. The specification for muck was that the fragmentation profile needed to be 100% < 400 mm (16 in) with no overbreak - with dilution less

Jan 1, 2019

By Marcello Crispi, Valdir Silva, Juarez Moraes

Companhia Vale do Rio Dote - CVRD is the largest mining company in Brazil and the largest iron ore producer in the world. Serra Geral Mine (SGM) is located at Iron Quadrangle of the State of Minas Gerais, approximately 80 kilometers from Belo Horizonte. Hematite and Itabirite are the two main minerals. A blasting with a spherical charge has been introduced at Serra Geral Mine, an iron ore producer in Brazil, belongs to the CVRD (51%) Kawasaki Steel Corporation (24.5%) others (24.5%), in order to improve fragmentation, as well, load, transportation and crushing productivity. This paper will present the results of a successful blast design with a spherical charge carried out by Serra Geral Mine, the Department of Mining Engineering at Escola de Minas - Federal University of Ouro Preto-UFOP associated to a Blasting Engineering Consultant. The results obtained in the field tests and how it was possible to increase the blast pattern in 53%, which allowed one reduction around 31% in the cost of blasting operation in the Serra Geral Mine, will be discussed in details.

Jan 1, 2002

By Joseph Haid, om, Rio Yang, Kelly Fleetwood

Some coal mining operations in the Powder River Basin are currently observing a number of blast holes detonating sympathetically within their cast blasts. Sympathetic detonation can cause poor cast results, high blast vibration levels, excessive back break and fly rock, along with a number of other undesirable blast results. The reduction or the total elimination of blast hole sympathetic detonation is of paramount importance to the coal mining companies operating in the Powder River Basin. This paper describes a systematic approach to prevent cast blast holes from detonating sympathetically through the use of the electronic initiation and expanded blast patterns. In-situ measurements outlined in this paper were recorded from pressure probes, velocity of detonation probes and near field accelerometers, along with digital images generated from a high speed CCD camera. Large diameter angled drill holes were also checked for any measurable amount of deviation by a cable type borehole measurement tool. The field measurements provided the scientific evidence, statistical data, and documentation necessary to develop a sound method or a “road map” that would minimize and in some situations prevent the occurrence of blast hole sympathetic detonation.

Jan 1, 2005

By Alastair Torrance, George Boucher

The authors were involved in the Trial Blast work at Chek Lap Kok, the site of the new Hong Kong Airport. As part of that work a series of computer programs including 3x30, QFRAG, DESIGNER and 3DMUCK was employed to predict various aspects of the trial blast programme. These aspects included fragmentation and muckpiie shape. This provided an excellent opportunity for these programs to be calibrated, verified and compared under controlled conditions. The results indicated that computer simulation has reached a high level of sophistication and good correlation between prediction and measured results was found.

Jan 1, 1994

By Lyle Dennis

Emphasis on increased production while maintaining rigid quality standards has necessitated a change in blasting technology at Dacotah Cement's limestone and gypsum quarries. The following three methods implemented during the past three years have yielded an increase in production through improved fragmentation.

Jan 1, 1996

By Lyall Workman, Jack Eloranta

Blasting has an important impact on mining and milling well beyond the necessary ability to dig and load the ore efficiently. There is an increasing body of blasting research indicating significant impacts in crushing and grinding. These include increased production through higher output and fewer delays for bridging and jamming by oversize. In addition, fragmentation better suited to the crushing and grinding system is indicated to lead to reduce energy consumption by these activities, an important result in today’s environment. An important component of optimum fragmentation for this purpose appears to be micro-fracturing within individual fragments. This differs from fragmentation criteria for loading which focus mostly on fragment size. Therefore, one must analyze blasting broadly to obtain satisfactory results throughout the operation.

Jan 1, 2003

By Garfiansyah Rayes

In 2023, an Indonesian coal mine experienced significant contamination of an emulsion blend explosive by dynamic mud and water flow, triggered by flooding due to exceptionally high rainfall. This intrusion into explosive columns compromised the stability and efficiency of blasting operations, thereby impacting overall mining productivity. The extent and impact of these contaminants on the stability and performance of the emulsion blend explosive were rigorously analyzed through a robust assessment methodology that included comprehensive field measurements and controlled laboratory experiments designed to replicate the challenging site conditions. Utilizing a combination of theoretical calculations and Computational Fluid Dynamics (CFD) simulations, this study evaluates the kinetic interactions between dynamic mud flows and emulsion explosives within drill holes. The methodology integrates Torricelli’s theorem for velocity assessments and Darcy’s Law for understanding the penetration mechanics of mud into the emulsion blend. CFD simulations are further correlated with actual blast data to assess discrepancies between theoretical predictions and real-world outcomes. Results demonstrate a significant reduction in the velocity of detonation (VOD) of the explo-sives, traced directly to mud contamination levels, which align with the quantified penetration rates in the study. Practical measures for mitigating such contamination are proposed, including the reinforcement of water-ways, culverts, and bund walls at drilling locations based on validated simulation data. Additionally, rec-ommendations for operational adjustments during high rainfall events are discussed, aiming to enhance blasting safety and efficiency. The paper concludes by suggesting future research directions towards the development of more resilient emulsion formulations and enhanced predictive modeling techniques to better forecast the impacts of en-vironmental variables on explosive performance in mining operations

Jan 21, 2025

By Michael Ostrowski

While the words “explosives” and “blasting” cause insurers to become apprehensive, skilled contractors using modern techniques under controlled conditions rarely cause serious damage or injury. However, blasting operations frequently result in complaints and, consequently, insurance claims. The purpose of this bulletin is to inform construction project participants of some of the measures which may be taken to reduce losses arising from blasting operations.

Jan 1, 2003

By Steve Dillingham

Change occurs all of the time. In fact, it’s fair to say that change is a constant. Sometimes the change is inconsequential, but sometimes the change impacts us d i rectly and severely. Take regulations, for instance. Complying with regulatory requirements is just part of the job for those involved with explosives. But in recent years, it seems as if new or revised regulations in areas such as hazardous materials training, drug and alcohol testing, security issues, or local licensing/permitting standards are changing the way we operate on a recurring basis. Simply keeping track of all of these regulations has become a full-time job.

Jan 1, 2003

By James Rowland, Isaac Zlochower, Richard Mainiero, Michael Sapko

The National Institute for Occupational Safety and Health (NIOSH) carried out exploratory laboratoryscale studies to identify factors that may contribute to nitrogen oxides (NOx) production associated with non-ideal detonation of blasting agents. Explosive admixture with drill cuttings, loss of fuel oil in ammonium nitrate and fuel oil (ANFO) from wicking, ammonium nitrate dissolution with water, degree of explosive confinement, ANFO density, and critical diameter were identified as contributing factors to increased NOx production under the laboratory test conditions. Experiments were also conducted to examine the effectiveness of various additives in reducing the NOx production from ANFO, emulsion, and ANFO/emulsion blends. Aluminum powder, coal dust, urea, and excess fuel oil in ANFO formulations were tested and were found to reduce both the nitric oxide (NO) and nitrogen dioxide (NO2) production. Fumes measurements were obtained in the NIOSH underground closed chamber from the detonation of 4.5-kg (10 lbs) charges in schedule 80 seamless steel pipe and from detonations in light weight galvanized steel stove pipe. Some exploratory tests were also conducted with 0.8-kg (1.8 lbs) charges of pulverized ANFO initiated with 0.08-kg (0.18 lbs), 50/50 (Pentolite) boosters (in the NIOSH 12-ft (3.7-m) diameter steel sphere) to measure the degree of fumes production associated with post-detonation oxidation. Ammonium nitrate, emulsion and Pentolite boosters were also detonated in an oxygen-poor environment.

Jan 1, 2002

By Steve Dillingham

There are some blasters and blasting companies that just seem to have better safety reputations than others. This is in spite of the fact that they are essentially doing the same type of work under similar conditions. To achieve that enviable safety reputation, it simply comes down to a strong safety culture prompted by a responsibility for others, as well as yourself and your company.

Jan 1, 2003

By Thomas Pallua, William C. Gates

"Two major railroad companies have identified several segments along the railroad corridor betweenTehachapi and Bakersfield, Kern County in California that require construction of a second track to improve operations in this area. The total project proposes an upgrade of five segments along the Tehachapi-Bakersfield route. The authors focused on two segments: Walong to Marcel and Cliff Siding Extension. The second track project comprised design of a through-cut adjacent to an existing tunnel and up to 120-feet-high (36m) side-hill cuts (both in granitic rock). The authors characterized the geologic ground conditions and ground behavior, including rock mass quality and strength using a combination of rock core drilling and rock slope mapping. The rock mass is generally characterized as granitic tonalite with strong core stones surrounded by a matrix of decomposed granite (DG)."

Jan 1, 2017

By Randall Wheeler

In early 2008 we were asked by a quarry to become involved in a conflict with a pipeline company concerning blasting near one of their underground high pressure gas lines. The pipeline company, without the quarry’s knowledge, had sought and obtained a temporary restraining order against the quarry forbidding them from blasting near the pipeline.

Jan 1, 2011

By Larry Ng, Keith McDonald

The benefits of controlled blasting techniques have gained increasing recognition by the mining industry in recent years. The utilization of an effective controlled blasting programme can result in a safe work environment with less loose rock and a reduced level of scaling and ground support.

Jan 1, 1994

By Yong Pan, Purushotham Tukkaraja

In this paper, CFD was used to investigate the blasting toxic fume characteristics under different entrapping percentages and under changing muck pile properties like broken rock size and porosity. It showed that CFD was a very useful method to study blasting fume in an underground mine and it took much longer time to dilute toxic fume into a safe level with higher entrapping percentage. The dilution time increased with a decrease of broken rock size and porosity.

Feb 1, 2020

By Jerry Wallace

Construction of a new grammar school required blasting within three meters of the existing school. Due to changes not anticipated at time of bid opening, blasting had to take place while approximately 200 children were in attendance inside the building. Blasting with children in such close proximity forced the blaster to review and revise a systematic approach to construction blasting and make changes to previous Rules of Thumb guidelines. The revised rules of thumb place Blaster-in-Charge at the top of the List. Other changes specific to the project included putting in place a blasting safety plan that included communicating the serious job hazards to teachers and students. The plan included stringent lockdown guidelines establishing school procedures for accounting for each student prior to the countdown-to-blast being implemented. Emergency communications channels were kept open so that any scheduled blast could be aborted at the last instance.

Jan 1, 2001

By Yong Pan, Purushotham Tukkaraja

Block caving is a preferred underground mining technique due to its high production rate and low operation cost. Before its final step into a mature caving system using gravity to break rock, drilling and blasting are required to form drawbells to connect the production level and undercut level and induce the initial caving propagation in undercut level. A large amount of toxic fume generated by blasting activities poses a big threat to people working in a confined environment and ventilation is assumed to be the most economical and efficient way to deal with this issue. Past research shows that it’s common to use traditional methods like using a formula or using numerical method (Computational Fluid Dynamic (CFD)) simulation to predict re-entry time after each blasting, but it fails to consider the percentage of toxic fume entrapped in muckpile, which could reach up to 70%. In this paper, CFD was used to investigate the blasting toxic fume characteristics under different entrapping percentages and under changing muck pile properties like broken rock size and porosity. It showed that CFD was a very useful method to study blasting fume in an underground mine and it took much longer time to dilute toxic fume into a safe level with higher entrapping percentage. The dilution time increased with a decrease of broken rock size and porosity.

By Ginn Huh

The blasting work to construct a subway in Seoul, Korea have often caused increased neighbor’s complaints because of ground vibration. In order to prevent the damage to the structure, it was necessary to predict the level of blasting induced vibration and to determine the maximum charge weight per delay within an allowable vibration level. The effect of blasting pattern, rock strength and different explosives on the blast-induced ground vibration was studied to determine the maximum charge weight per delay within a given vibration level. The blasting vibration was measured from 10 sites along the subway line in Seoul and an empirical particle velocity equation from over 100 test data was obtained, V=K(D/W1’3 )-” , where the values for n and K are estimated to be 1.7 to 1 S and 48 to 138 respectively.

Jan 1, 2000