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Investigating blast vibrations typically utilises scaling and attenuation models for prediction of vibration amplitude over a range of charge weights and distances. A number of generalised relationships have been established from many years of far-field data analysis, where small changes in charge weight and ray-path distance are less critical. Under far-field conditions, small variations in local geology or geometry do not significantly affect the vibration scaling behaviour over an expected range of data. In the near to intermediate-field (less than 5 times the explosive charge length), small variations in wavepath and rock mass conditions between a blast and a monitoring point can greatly affect the outcome of vibration modelling. This case is especially true for underground blasting in sublevel open stoping, where the paths of blast-induced vibrations regularly encounter voids and preconditioned ground.

Jan 1, 2010

By K. Hausmann, P. A. Sashin, G. J. Prejean

Misfires caused by unreliable shock tube constructions can have significant cost implications and place field workers at serious risk during remediation. Ionomer materials, used as a subtube in shock tube constructions, provide superior hot tack strength, oil resistance, impact resistance at cold temperatures and excellent thermoformability properties. These are important features for resisting blast-throughs and ensuring blasting reliability in demanding environments, such as open pit mining in harsh environments. Superior hot tack strength, strain hardening, and excellent thermoformability properties of the ionomer materials ensure uniform powder distribution along the shock tube during construction and avoid undesired powder accumulation due to deformation or vibration during use. Oil or chemical resistance is another feature of Ionomers. This allows improved property retention in contact with oils and hence longer sleep times of the shock tube. Another feature of these highly engineered ionomers is superior impact strength at low temperatures. This plays an important role considering the resistance to fly rock impact in open pit mining operations in particular in cold climates.

Jan 1, 2011

By Italo Onederra, Gary Cavanough, Ewan Sellers

Reactivity of ammonium nitrate based explosives is associated with the presence of iron sulfides in the ground reacting with explosive products and in some instances causing spontaneous reactions which can lead to detonation. The stability of explosive products can also be linked to in-hole density, which influences detonation efficiency, breakage performance and the potential generation of Nitrogen Oxide (NOx) fumes. Reactive ground testing involves detecting a temperature rise of a mixture of a bulk explosive product sample, a ground rock sample and some specific chemical agents. This paper describes improvements in reactive ground testing involving the use of time lapse video analysis and detection of NOX gas emissions from the sample. Reactivity is stored and linked to a using cloud based software to map of the mine showing the exact location of the sample. The location marker can be selected to allow quick access to the sample test results and video. In addition to reactivity, the stability and detonation performance of bulk product can also be influenced by depth. In this paper, a system that simulates product at depth and measures density changes and monitors the structure of bulk samples is described. Results from an explosive product are analyzed and detonation performance is assessed by the measurement of velocity of detonation and detonation pressure.

Jan 1, 2018

By R D. Skaggs

A good blast is dependent on a well engineered design. However, a good design's performance depends on the control of the drilling and loading of the blast holes. The key stone to good blasting is the drilling of straight holes of the correct orientation in the required positions.

Jan 1, 1991

By Roger N. Prescott

This report presents a new process in delay blasting with the use of ANFO and slurry explosives.

Jan 1, 1977

By Cam Grundstrom

The Ok Tedi Mine is a large open pit copper and gold mine located in a remote section of the Western Province, Papua New Guinea, with an annual rainfall of over 10 metres. Ok Tedi mines an average of 205,000 tonnes per day. A strong working co-operation between the mine operator (Ok Tedi Mining Limited) and the explosives contractor (ICI Explosives Asia / Pacific) has led to progressive development of bulk emulsion formulations to meet site-specific needs, continued improvement to blasting applications, and competency based training programs for the national blast crew.

Jan 1, 1997

An explosive's velocity of detonation (VOD), can be used to indicate a number of important characteristics regarding the product's performance under specific field and test conditions. A number of new characteristic and transient VOD curves have been identified in the field, which can be used to evaluate explosive performance, control ground vibration amplitudes and frequencies, select the correct amount and type of stemming for use at the collar and in stem decks, eliminate explosive desensitization, evaluate primer performance, design air deck based blasts, evaluate contaminated explosives and to overcome post blast noxious fumes.

Jan 1, 1994

By Duane A. Houkom

Explosive demolition of concrete has been accepted as a safe and economical means of concrete removal for many years. I imagine that the early concrete blasters were experienced rock blasters who applied their knowledge to just another formation. Since a concrete foundation is generally located in a congested area, the owner is willing to accept the higher costs of mechanical removal,rather than promote "a new idea" to his management. This attitude is rapidly changing,making it possible to use the advantages of explosives in more congested locations.

Jan 1, 1982

By Charles H. Dowding

This paper describes NUVIB, analytical software to digitize, analyze, display, and plot time histories generated by blasting and construction vibrations. It is available in conjunction with a new book on Construction Vibrations (Dowding, 1996) through internet procedures described at the end of the chapter on analytical software These internet based procedures eliminate the need for inclusion of disks in the book and take advantage of the growing electronic communications network. Perhaps more importantly this procedure allows the software to be updated more often than the book is reprinted.

Jan 1, 1997

By Wang Xuguang Shen Yingfeng

Structure is the main aspect affecting the performance of emulsion explosive. Calculation of such structure parameters as osmosis pressure, interface area per unit volume etc. must be helpful to the understanding of the structure of emulsion explosive. This paper has solved the Laplace-Young Equation for simplified monodisperse emulsion system by Galerkin method, and gained the relationship between mean curvature, contact angle, volume fraction, fractional film area and interface area per unit volume. The paper also presents a new expression of osmosis pressure at non zero contact angle.

Jan 1, 1998

By R Yang, D B. Kay

"Blast vibration control is of vital importance for tunnel blasting in urban environments. A vibration model with multiple seed waveforms (MSW) as input for a point of interest was developed in recent years by one of its authors. The MSW blast vibration model has been applied successfully in open cut and quarry blasting situations. From the literature, it appears that there may not be any seed wave-based vibration modelling work for tunnel blasting.A project was conducted to test the MSW model for tunnel blast vibration. A series of tunnel blast rounds were fired and tri-axial vibration waveforms from the blasts were recorded with several seismographs at distances ranging from 10 to 100 metres from the blasts. Seed waveforms were collected and the charge weight scaling law for the signature hole PPV were established.The MSW model is applied to tunnel blasting and specific issues associated with tunnel blast vibration addressed, such as variable effects of confinement and screening to vibration during a blast round. The capability of the model in terms of the PPV and frequency prediction is demonstrated in the paper. The paper demonstrates that the MSW blast vibration model is a useful tool for managing tunnel blast vibration with the potential to optimise round by round design in terms of managing the vibration below the limit while maximising tunnel advance rate."

Jan 1, 2011

By Ann Barron

Even though you think your company’s safety program is the best it can be, equipment, processes, supplies, surroundings and people do not always behave or react as expected. Consequently, needless accidents occur each year at quarries, construction sites, surface mines, and other locations where explosives are used. While blasting accidents account for only a small portion of the total accidents reported, the severity rate for blasting accidents is higher than for any other accident category.

Jan 1, 2007

By O E. Crenwelge

Seismograph measurements are usually made near blasting operations solely for the purpose of monitoring compliance with governmental regulations. However, recordings of seismograph signals have far greater potential than this, if the proper procedures are used for analyzing the transient data.

Jan 1, 1991

By Richard J. Mainiero, Harry C. Verakis, John J. Mulhern

There are application in coal mines where it would be advantageous from a safety stand point to fire unconfined shots. However, the firing of mud caps (adobes) or other unconfined explosive charges in underground coal mines is not permitted because of the explosion hazards associated with methane gas and coal dust. Present safety regulations in Title 30, Code of Federal Regulations prohibit such Practices. Recently, MSHA proposed revised coal mine regulations for the approval and use of sheathed explosives for Public comment.

Jan 1, 1987

By Ruilin Yan, Kameron Ray

This paper reports a simple approach to model the waveform change due to travel distances based on the field measurement. A linear interpolation is used to estimate the waveform at a distance from two vibration waveforms recorded at two different distances. The resulted waveforms are compared with actual recorded waveforms at the point in both time and frequency domains. It shows that the proposed method to estimate the waveform change yield reliable results. The advantages of the proposed method are that it does not require assumptions that a transfer function does and that it is based on purely the measured waveforms that are encoded with in-situ rock properties. The method could be more reliable for far field seismic waveforms and could be an approximation for near field waveform estimation.

Jan 1, 2014

By Frank Wilder, Mark Ferrero

One of the challenges currently facing the explosives industry is how to transition its workforce and its business systems to respond to the increasing pressures for improved inventory and records management. The pressures applied by many U.S. federal and state agencies, such as the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) and the Department of Environmental Protection (DEP), as well as regulatory agencies around the world, are increasing the need for accurate inventory accounting of explosive materials and blast documentation. With blasting companies now facing regular documentation audits, potential liability issues may arise due to the inconsistent or missing documentation.

Jan 1, 2006

By C. B. Navalkar

The optimization of blast design under consideration is for the conventional driveways in under ground coal mines with respect to board & pillar workings in India. Basically The Blast Design includes following parameters: AA> Drilling Pattern. BB> Charging Pattern. CC> Material & Method Of Stemming. DD> Selection of type & quantity of explosives. EE> Initiation system & Blasting Sequence.

Jan 1, 2002

By Gordon Revey

In construction and mining work, situations occasionally occur where hard rock or concrete must be excavated at locations near critical structures or utilities. Fearing damage from blasting, contractors and engineers often explore the viability of using mechanical methods or expansive concrete to facilitate the excavation work. However, for moderate to large excavations, the prolonged duration and high cost of using these methods is often impractical. In these situations, under the right conditions, controlled blasting and blast-management methods can be used to speed up the work and lessen costs. The process of determining whether or not blasting is practical is ofien complex, particularly when risks are high.

Jan 1, 2001

By Jim Daley

SEE is a dynamic organization composed of people from all facets of the explosives industry who are truly interested in the advancement of that industry. I had been a miner at the Homestake Gold Mine in Lead, SD for 12 years when I decided to obtain a mining engineering degree. The mental and economic consequences of that decision were more severe than we had imagined. The joint scholarship program of the Northern Plains and Black Hills Chapters of SEE provides assistance to several college students each year. I was fortunate enough to receive scholarships from this program twice and this assistance helped me and my family with both monetary and psychological support during times of need so that we could stay focused on the goal of obtaining a degree.

Jan 1, 1995

By Per-Anders Persson

This chapter deals with the concepts of shock wave8 and detonation wavea together, because a detonation wave is really a shock wave, supported by the explosive reaction that the shock wave ignites and propagates as it travels through the explosive material. In the context of rock blasting, furthermore, there is justification for treating shock waves and detonation waves together, because the mechanical effect of the detonation in an explosive in a drillhole in rock is propagated and its effects are spread throughout the surrounding rock by means of a shock wave. The overall performance of an explosive in rock blasting or any other application is of course dependent on how much thermal energy is released in the chemical reaction that occurs when the material detonates, and on how much useful mechanical work the reaction products can do as they expand. A major portion of thii chapter deals with the prediction and measurement of explosive performance, a subject which is now still in a process of rapid development.

Jan 1, 1998