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By Richard J. Mainiero, Eric S. Weiss

This project investigates the behavior of blast waves from the detonation of high explosives in an underground mine. A series of explosive tests was conducted in the underground and surface facilities at the Bureau of Mines' Lake Lynn Laboratory to evaluate the potentially dangerous effects of blast waves produced by open shooting, blown out holes, or accidental detonations of explosives. Shots of C4 and TNT were fired at the dead end of a 6 ft high by 20ft wide entry, at the intersection of two entries, and on the surface. C4 and TNT were chosen for this research because they exhibit very consistent performance. Behavior of the blast wave was evaluated through recording of the pressure as a function of distance from the explosive detonation.

Jan 1, 1995

By Kim Henley, Chris Batten

This paper discusses the use of the Orica WildFireTM flyrock model to help mining operations in Australia and Asia minimise blast exclusion zones for equipment, increasing utilisation and productivity and delivering downstream value

Feb 1, 2020

By Sérgio Augusto Ferreira, Alan Gerson Diaz Butron, Carlos E. Arroyo, Marcus Neves, Jorhs Enrique Casimiro Huayhua, Dieggo Santos, Eventomar Junior

The presence of natural underground cavities is normally a characteristic of iron ore deposits, specifically in tropical deposits. Brazil and the United States are the only countries that have a legislation to protect these structures, but in Brazil this legislation is very specific for the existing cavities in the federal territory. These cavities are classified by their level of relevance as high, medium, and low. From this perspective, its preservation becomes mandatory, especially, for those of high relevance in order to protect the species (flora and fauna) that live in them. When these structures are within the production phases, it becomes a challenge to exploit these reserves with the use of commercial explosives, since these structures condition and may restrict the use and amount of explosive charge. This paper presents the methodology of controlled blasting associated with predictability via realistic simulation in production polygons, applied in a Brazilian iron ore mine where there is a presence of high relevance natural cavities with restrictions in relation to the limits of Peak Particle Velocity (PPV), which is product of detonation.

Feb 6, 2023

By Craig Adams, William Poe

Introduction The United States Department of the Interior, Minerals Management Service (MMS) is mandated under the Outer Continental Shelf Lands Act (OCSL A) and the Energy Policy Act of 2005 to oversee leasing, exploration, development, and production of mineral and renewable energy resources on the Outer Continental Shelf (OCS). Under these authorities, MMS is responsible for permitting and overseeing an array of offshore operations; some of which involve the underwater detonation of explosive charges. Explosives are most critical for their use in the severance of bottom-founded piles and well components during the decommissioning of OCS platforms and well abandonment work.

Jan 1, 2011

By Patricio González Santis, Jacopo Seccatore

This paper documents drilling and blasting activities from gold mining in Ecuador and Chile. First, are described the outdated and often non-rational techniques employed by miners, to provide a general framework of the current methods. Then, it is shown what can be improved and how the current methods can be modified. Finally, are shown some field applications and the comparisons of the results obtained

Feb 1, 2020

By Jorge Alvarez

In a large-scale open-pit mining operation, continuous efforts are made to control damage to the slope walls. An essential tool in this effort is determining the PPVc (critical peak particle velocity) in areas of interest. By knowing this value and generating criteria, drilling and blasting designs can be established to reduce vibrations that affect wall construction. It is crucial to understand that the PPVc changes as different mining phases develop, especially due to exploitation on the benches, which leads to vertical inherited damage. Therefore, it is imperative to regularly update the PPVc based on field tests that provide accurate data. With this information, vibration damage criteria can be established, and drilling and blasting techniques can be designed to minimize the impact on the remaining rock mass. This document presents a methodology for generating scaled criteria that best represent the reality of the rock mass.

Jan 21, 2025

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 Andrew F. McKown

Overbreak and damage to rock walls at the perimeter of rock excavation can lead to safety problems due to rock falls and additional costs due to a] extra mucking, b] extra concrete or shotcrete to backfill overbreak, c] additional rock reinforcement, d] additional water inflow and e] additional maintenance of rock walls. To minimize these undesirable effects, there are several perimeter control techniques available (i.e. line drilling, cushion blasting, pre-splitting, smooth blasting, and fracture control blasting) which control perimeter hole spacing, burden and loading to provide a smooth, stable excavation contour. Conventional perimeter control loading and hole spacing is satisfactory for massive, homogeneous formations, but when blasting in weathered or fractured rock closer spacing and very light loading is required.

Jan 1, 1984

By Miquel Lamadrid, Changshow Sun, Chris Johnson

To reduce blasting overbreak and improve stope stability, several new blast designs were proposed for current and future stopes. Based on the analysis of the powder factor, and the extent of damage zone, the appropriate new blast design was selected. Excellent results were achieved from the new blast design. Comparing the new blast design with the old one, the largest of the overbreaks decreased more tan two times and average overbreak reduced more than two times. The new blast design is currently applied in all mining zones in Leeville underground mine.

Jan 1, 2008

By Brian Hawkins, David Bradley, Rachel Gooding, Lucas Rodriguez, Patrick Wilson, Kevin Wegman, Dhruv Mittal

To better protect the nation and inform difficult defense and preparedness decisions, the Department of Homeland Security (DHS) is performing a probabilistic risk assessment of explosive terrorism risk to the US homeland. After assessing existing models against requirements, well-developed mathematical descriptions and algorithms associated with explosives hazards were combined with probabilistic modeling techniques used in DHS chemical, biological, radiological, and nuclear (CBRN) terrorism risk assessments to create a suitable interior explosive consequence model for assessing the impact to human health.

Jan 1, 2018

By Finn Ouchterlony

"Recently detailed fragmentation data from blasts fired with electronic delay detonators (EDDs) in the Red Dog mine in Alaska were presented. They include a comparison with pyrotechnic detonators fordifferent in-­-row delays in a standard pattern and EDDs in an expanded pattern. Fragmentation was measured on the belt after the primary crusher. The Rosin-­-Rammler function (RR, two parameters) was used to describe the crusher product. This was combined with the JK SimMet crusher model and the CZM blast model (Crushed Zone Model, three to five parameters) to estimate a reasonable crusher feed (muck pile fragmentation or run of mine, ROM) for each fitted product. In this way the effect of delay timing and electronic detonators on the median fragment size x50 and uniformity coefficient n for both crusher product and the blasted rock was determined. "

Jan 1, 2012

By Leslie C. Taylor, Scott A. Yamada, William L. Fourney

Previous studies have shown that the pressure load on a target by a buried explosive charge is not smoothly distributed. The effort reported here was undertaken to explore the mechanisms believed to cause this uneven pressure distribution: jets from the surface originating in instabilities caused by the explosive shockwave interacting with surface irregularities. Small-scale tests using conical, hemispherical, and cylindrical indentations in the sand surface above a buried charge were conducted to identify trends in the velocity and form of the resulting jets. In these tests, the most important factor affecting the resulting jets was the distance between the bottom of the indentation and the top of the charge. Cylindrical indentations resulted in higher jet velocities than those from comparable hemispherical and conical indentations.

Jan 1, 2012

By Peter Moser, Andreas Grasedieck

In modern rock blasting it is becoming more and more important to achieve a certain specified fragmentation. This means that the rock particles formed as a result of the blast should conform to a desired particle size distribution. An important issue with respect to achieve a desired blast result in terms of fragmentation is both the availability of models for the prediction of the characteristic of the particle size distribution of blasted material and the determination of the energy necessary to achieve a certain fragmentation status. Within the research project “Less Fines” funded by the European Union under project reference G1RDCT200000438, the latter has been addressed by the Department of Mining Engineering& Mineral Economics of the University of Leoben. For that purpose fragmentation results from lab scale blast tests have been analyzed and the relationship between the specific charge used for the blasts and the resulting specific surface of the fragmented material has been examined. Linear relationships between the specific charge and the specific surface of the resulting fragmentation were found for various types of rocks to apply over a range of 10 for the powder factor.

Jan 1, 2004

By Peter Moser, Mark Ganster, Radoslava Ivanova, Florian Bauer

Blasting accurately in underground drifts and creating a smooth contour requires proper drilling, knowledge about the apparent geology, a well designed blast pattern and ideally a smooth blasting product. These products are usually cartridged explosives with less energy and are charged in the contour holes in order to reduce the energy concentration and therefore the cracking into the surrounding rock. With the development of a new contour blasting system, a device can now be delivered to the industry that that avoids the additional storage of cartridged products when bulk explosives are used. The system consists of a foldable hose that is charged with bulk emulsion, in the same way as the rest of the blast, from the base to the collar of the hole. It centers automatically in the borehole and provides a decoupled charge. The paper describes the system in detail, gives background information on smooth blasting and presents the first successful field tests using the system in the drifts of an underground mine. It shows the advantages of blast results that produce more stable contours that reduce the amount, time and cost for support but also increase safety underground.

Jan 1, 2012

By Winfried Rosenstock

AEBT has been available for a couple of years and is successfully applied in Australia. Up to now it was mainly used in coal surface mining at the Australian East- Coast. Presently, the proved results reach ~ 50 % reduction of Drilling & Blasting costs and a productivity increase of between 10 and 20 %. In 2003 it was for the first time used in surface metal-mining. The mine features for the time being an extremely difficult geological environment and had above to be carried out in the transition level waste/ore. Reductions of wall control, powder factor and vibrations were the main target.

Jan 1, 2004

By Mark A. Rugen

It may be difficult to imagine but small engineering companies do exist, even in relatively large cities like San Antonio. Due to the limited capital available for the purchase or use of equipment such as computers, many times the small company must evaluate a blast damage claim by limited means. This paper will discuss how a relatively small company has managed to become the leading blast damage experts in an area without the use of computers or sophisticated equipment. It will be shown that a single individual in a company who is familiar with vibration theory, local soil conditions and who does not mind spending long hours with a calculator and reference books can satisfy both the insuranc e adjuster or attorney, and the homeowner concerning the claim. Several examples will be given which show the typical flow of work and the ultimate outcome. This paper will focus on the special problems encountered by a small firm and how these can be overcome, and the unique interaction of a small engineering firm with both the insurance adjuster/attorney and the homowner that can lead to an equitable settlement of the claim.

Jan 1, 1983

By Raúl Mondaca Aracena

Mantoverde mine requires increasing its production level to double. EMTS - Projects performs far and near field vibration studies to make changes to the D&B design and sequences, in order to equalize the current vibration levels, applying massive blasting in its process.

Feb 1, 2020

By Chick Kerkering, Stephen Iverson

Perimeter control blasting is common in civil construction projects but not as common in mining. A poorly designed and executed underground mine development blast design can result in unwanted wall rock damage. This damage increases the risk of rock falls and injury. With the availability of good drilling equipment, it is a simple matter to add the few extra holes needed to change conventional drifting into drifting with perimeter control.

Jan 1, 2008

By P D. Katsabanis, S Kim

A number of small scale fragmentation tests have been conducted to analyze the effects of blasting effort on the grindability of granite, granodiorite, limestone and iron ore. Powder factors were modified, post-blast fragments were screened and drop weight tests were conducted on fragments of different sizes to deliver a variety of specific impact energies. The fragmentation from the drop weight tests has been analyzed to examine the effect of impact energy and powder factor on size reduction. A consistent effect of blasting on the various fractions of the fragmentation distribution has been obtained for all rocks used. The effect of powder factor on the impact fracturing of the rocks has been expressed in a convenient relationship between progeny size, impact energy and powder factor used in obtaining the primary fragmentation. It is clear that explosives consumption affects downstream size reduction; depending on the rock, the effect can be substantial at coarser final sizes but very small in the case of grinding to small final sizes. Differences from the expected trend can be attributed to changes in blast design. As an example, the effect of in-hole collision of detonation waves is analyzed.

Jan 1, 2011

By Joel Chipana, Roberto Laredo, Benjamin Cebrian

Ring blasting is a common production method in underground metal mines. As a drill and blast process, it presents particular features that do not correspond with bench blasting in open pit or underground mining.

Jan 1, 2017