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By Stuart Brashear, Robert Brush, Ben Cook

In early 1993, the Piney River quarry owned and operated by the Blue Ridge Stone Corporation of W.W. Boxley, received a series of complaints from the owners of a 130 year-old historic farmhouse that had been converted into a bed and breakfast establishment. Since the distance from the quarry to the farmhouse was substantial, a unique method of seismic data acquisition was utilized to determine if perceived blast effects were caused by air blast or low amplitude, low frequency ground vibration.

Jan 1, 1995

By Jean M. Bouvet, Pierre M. Vuillaume

There is not just one ANFO: ANFO explosive behaviour depends significantly on the blasting conditions and on its physico-chemical characteristics. For instance, ANFO effficiency increases whereas AN porosity is higher and consequently loading density of the explosive is less. This can be argued against generally admitted ideas. Therefore, the efficiency of industrial explosives related to ANFO (for example "relative weight strength" or "relative bulk strength") is a tool that must be used with caution.

Jan 1, 1993

By Romel Villanueva L.

"Peru does not produce ammonium nitrate; nevertheless it is a large consumer of both, porous prill (PP) and high-density (HD) varieties. Explosives cost is an important preoccupation in Peru, due tofluctuations of the imported ANFO grade Ammonium Nitrate (AN). The use of Gasified Emulsion (GE)-manufactured with much cheaper HDAN- has become an alternative to reduce such costs. However, some problems were reported in the application of pure GE, including explosive percolation in highly fractured rock and lack of sensitivity by the effect of hydrostatic pressure in very deep holes. It was, hence, proposed to have an explosive based on GE too, but more robust and capable to keep the shape of the explosive column into the blast hole, by minimizing the leakage into the cracks. This could be achieved by adding limited amounts of lower priced HDAN, at the same time of providing gas pressure benefits. Other alternative is to add a low-density material, such as polystyrene prills, into the GE, although it reduces the explosive energy. The chemical gassing controls the density of GE, thus it can be obtained a wide range of densities."

Jan 1, 2016

By Henry P. Jr Van Ormer

During any blast hole operation the first choice to be made is hole size - it seems simple, just calculate all the factors, spacing, burden, depth, rock characteristics, powder factor, etc. and you have it - Hole Size. But we all know that it is not that easy - the "hole size" is part of a system and many other situations can have great impact on the optimum production Blast Hole Size - such as crusher characteristics, hauling capability, mucking capability and - Drilling Capability!

Jan 1, 1983

By John Floyd, Maria Rocha, Benjamin Cebrian

Wall control blasting is needed in most metal mining operations in terms of increasing mineral reserves and assuring the safety of the operation. This type of blasting has the goal to achieve a clean, stable rock wall in the shortest distance from a well fragmented, easy to excavate, blasted rock mass. This can be done with a variety of blasting techniques, all of which decrease the explosive energy towards the final wall. Each technique needs to suit the geology: modified production blasting, buffer blasting, pre-split and line drilling of empty holes. Pre-split is the most expensive technique, and allows final steeper bench face angles while modified production blasting is the least expensive but needs wider berms.

Jan 1, 2018

By Bjorn Engsbraten

Explosive charges have been fired under defined conditions in a closed tunnel. The explosives have either been detonated in a steel tube or a single borehole. In the latter case dimensions, -loading density and confinement have been chosen to correspond to common practice.

Jan 1, 1980

By Jody Todd, Ernesto Villaescusa, Ronald Lachenicht, Kelly Fleetwood

In the underground environment, characterisation of a rock mass during the mining cycle becomes increasingly difficult due to a lack of rock mass exposure for measurement or observation. In most cases rock mass characterisation occurs prior to mining by inspection and logging of exploration drill core, or prior to mass excavation through drive mapping for geological and geotechnical data. Characterisation strategies, if applied during the mining cycle, can reveal near-field anisotropies that may affect the behaviour of the rock mass with respect to excavation. These methods can aid in understanding the performance of stopes based on geometry, in-stope extraction sequence, and stress modelling. One such method of characterisation involves the use of production blast vibration monitoring and analysis as indicators of rock mass anisotropy through travel-time tomography.

Jan 1, 2008

By H P. Rossmanith

This contribution addresses the advanced blasting technology which is based on wave propagation theory and fracture mechanics. The new concept of sonicity and the principle of maximizing sonicity in blasting as well as the energy or work of a blast operation will be introduced. It is shown that - in contrast to common belief – it is not the velocity of detonation which controls the blast but the relationship between velocity of detonation and the wave speeds, in other words, the Mach numbers of the blast operation. Based on numerous practical blasts in Germany, the authors show that, when using wave dynamic concepts, there is a linear relationship between peak particle velocity and the work of a blast operation and this linear relationship is controlled by the sonicity of the blast. Extensions to layered and faulted rock masses are presented. It will become clear that a second change of paradigm is enforced, the first one being the implementation of short time delaying. Again, the acquisition of knowledge in wave progation theory and fracture mechanics becomes mandatory in advanced blasting technology, where the art of blasting is now fully transformed into a science of blasting with little room for methods of trial and error.

Jan 1, 2010

By Chris Vagasky

On July 10, 1926, lightning struck at Picatinny Arsenal, New Jersey, and caused the explosion of at least 600,000 pounds (272,000 kilograms) of ammunition, resulting in more than $600 million (2015 dollars) in damage, the destruction of 200 buildings, and 22 deaths. Fortunately, there has not been a major incident involving lightning and explosives in the US in some time, though lightning has destroyed fuel storage tanks in recent years, including in North Dakota, Texas, and Ohio. Lightning poses a significant hazard to the explosives industry. Carrying high currents and temperature, lightning can cause explosives to detonate, start fires near storage facilities, and injure or kill operators.

Jan 1, 2017

By Peter Reinders, Dirk Hummel

This paper describes a new digital Centralized Blasting System (CBS), which is currently being introduced into underground applications. The CBS makes use of the field-proven detonator and equipment technology of an electronic detonator system and existing mine radio communication networks. Therefore no capital investment for additional mine infrastructure networks is required for the deployment of the digital CBS. Components of the new system are a Remote Blasting Box for use at the actual blast site and a Master control unit ‘Lockbox’ which is located at the central blasting location of the mine. The system is operated via a PC based centralized blasting software. Several sophisticated safety devices guarantee the highest safety standards are maintained with the application of the new digital CBS.

Jan 1, 2004

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 Jorge Flores, Dean Nichols

Some view quantitative risk assessment (QRA) as difficult to understand and complicated to use. They are comfortable with the proven reliability of quantity distance (QD) and question the benefits of applying QRA principles to explosive safety. In response to such questions, a review of the history of the American Table of Distances (ATD) provides insight to the strengths and weaknesses of the concepts behind QD tables. Additionally, a closer look at QRA features that are available today will reveal stunning capabilities and improved user friendliness not available previously. This paper looks at the early days of explosive safety, the use and limitations of QD, the meaning of risk in the context of QRA and discusses recent developments that knock down barriers previously hindering acceptance of QRA among regulatory agencies.

Jan 1, 2015

By Braden Schmidt

The following full paper will go into the products, techniques and people who work in the avalanche control industry giving insight to the other members of the ISEE an overview of the niche blasting that is Avalanche Control.

Feb 1, 2020

A major problem that has continued to plague the surface coal industry is blast induced damage to the coal seam. Atlas Powder Company has addresssed this situation through seven years of field research in full-scale production environments. Many operations across the United States have been evaluated.

Jan 1, 1990

By R. J. Cefalo

Blast and mining spillover between phases or critical areas of the pit is a continuing problem in the mining industry and a safety concern for operating mines. The challenge for many mines is to produce the highest value in the shortest amount of time for any project. For any project, the top priority of any mine is producing ore as fast as possible. The next challenge is to keep that ore feed continuous. To achieve continuous ore feed, pits are designed with multiple phases that are connected and are mined at different elevations. This difference in elevation causes dangers with spillover between the phases during mining, drilling, and blasting. This paper covers an incident that occurred at an active mine and the work completed in creating a spillover control program over an active mining phase. The drill and blast technical group was responsible for creating blast patterns to reduce spillover between these phases. Unrealistic goals and expectations were initially set for the area of the pit. The drill and blast technical group needed to figure blast objectives and work with the geotechnical team to align with these goals. This paper will go over the executed example of setting up spillover targets and expectations for multiple sections of an operating mine. Different sections of the pit had different control measures and blast objectives due to narrow laybacks and double benching. The use and value of blast objectives and goals were beneficial in setting expectations and measuring design success. Having unrealistic blast goals can set up the operations to fail or get frustrated in trying to work on an impossible task. The problems and risks of phase interactions for many open pit operations need to be considered in the design process, along with designed controls that minimize the probability of any safety incident. Mine designs are being created in the industry and do not consider phase-to-phase mining interaction and the impact it would have on safety or production. The best future for safer mines is blast patterns that reduce spillover between phases of mining and pit designs that might account for spillover interaction.

Jan 1, 2024

By Cary Moffat, John Kita, Rick Walker

The Lac des Iles Mine, in an isolated area of NorthwesternOntario is a relatively new open pit platinum and palladium mine. They were encountering problems with the equipment and production scheduling when ramping down to begin production on the subsequent benches. A co-operative effort between Lac des Iles Mine operation people, ICI Explosives, and the mines drilling and blasting contractor - Consbec Inc., resulted in a decision being made to use full depth sinking cuts to provide access to the next bench.

Jan 1, 1996

By Alton Dunaway, Kevin Sullivan, Charles Gray, Doug Hall, Kevin Grant, Kelly Thiel, John Paulson, Bruce Leland, Cole Boyd

Beaver (Castor canadensis) are responsible for economic losses exceeding $4 billion over the last 4 decades in the southeastern United States alone. A large portion of these damages occurs to public roads and highways, forests, agricultural resources, and other property from flooding caused by beaver dams. The United States Department of agriculture, Animal Plant Health Inspection Service, Wildlife Services (WS) program is a non-regulatory Federal program directed by Congress to assist resource owners with managing damage caused by wildlife.

Jan 1, 2007

By David Porter, Nathan Rouse

The implementation of presplit blasting has been widely utilized in open pit and underground tunneling. This case study works through the iterative process of developing a heading drill and blast design to control overbreak and limit backbreak in cut and fill headings. The initial design was based on rule of thumb parameters, and the design was then modified for the field conditions based on results. Throughout the design process the drill profile, explosive charge, and timing were modified to yield the best profile compared to design. Data collection during the design process was extensive to best understand the effect of modifying parameters, and gauge performance of design changes. Input from the miners as well as engineers was considered to allow for the best possible adaptation of the design change from existing practices. During the process resistance to change was realized and accounted for to understand the issues that the miners were facing and how to best address them while ensuring high quality blasting. Workforce buy- in was addressed by illustrating the long term benefits of higher quality blasting and the tradeoff of with a slightly more in depth drill and loading cycle.

Feb 6, 2023

By Ali Kahriman, Abdulkadir Karadogan, Umit Ozer, Mehmet Aksoy, Deniz Adiguzel

The environmental problems arising from ground vibration has been faced and discussed frequently in various industries such as quarry, mining, civil works, shaft, tunneling, pipe line and dam construction etc. where the blasting operations are unavoidable. In bench blast design, not only the technical and economical aspects, such as block size, uniformity and cost, but also the elimination of environmental problems resulting from ground vibration and air blast should be taken into consideration. The prediction of ground vibration components plays an important role in the minimization of the environmental complaints. This paper presents the results of ground vibration measurements carried out in the quarries located on the different sides of Çatalca district in Turkey. In order to predict peak particle velocity level for this district, ground vibration components were measured for shots during bench blasting at these quarries. In blasting operations; ANFO is commonly used as blasting agent at the quarries. The type of priming and firing differed from quarry to quarry. The parameters of scaled distance (charge quantity per delay and the distance between the source and the station) were recorded carefully and the ground vibration components were measured for all blast events by using different type vibration monitors. The absolute distances between shot points and monitor stations were determined by using GPS. The equation of square root scaled distance extensively used in the literature was taken into consideration for the prediction of peak particle velocity. In order to predict, and compare the influence grades to the neighboring buildings, and structures at the Çatalca district, the particle velocities and frequency values of all blast events are evaluated according to the United States Bureau of Mines (USBM) and German DIN 4150 Norms due to the lack of a national standard in Turkey. Then, the data pairs belonging to these quarries were gathered together to represent the district and were analyzed statistically. At the end of statistical evaluation of the data pairs, an empirical relation which gives average line at 95% confidence level and upper bound 95% prediction line with a reasonable correlation coefficient was established between peak particle velocity and scaled distance

Jan 1, 2007

By Robert B. Hopler

The hazards which naturally prevail in underground coal mines, always severe and unpredictable due to the loosely-consolidated strata in which coal is frequently found, are increased by the commonly-occurring combination of coal dust, methane, and explosives. It was recognized by the mid-nineteenth century that coal dust was the basic factor contributing to disastrous explosions killing hundreds of miners, and that the ignition of methane gas was often the source of the coal dust explosions. It was apparent that preventing the ignition of methane was a critical part of avoiding these disasters, and it was also apparent that one cause of such ignitions was the firing of explosives. In addition, it was found that dust explosions were often initiated by blown-out shots of explosives in the absence of methane.

Jan 1, 1996