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By Italo Onederra, Miguel Araos

"In order to characterize non-ideal explosives, the explosives industry rely on unconfined velocity ofdetonation tests and where possible underwater pond tests. The information obtained from such tests isquite helpful, however it cannot tell us much about the dynamics of the detonation reaction process. The detonation process has been studied for ideal explosives and the reaction zone length have been measured. However, for non-ideal explosives, that type of information is not available. Therefore, the primary aim of this work was to capture the detonation process of a non-ideal explosive using high speed video camera to determine the zone length."

Jan 1, 2017

By Dale Preece, Joergen Pilz, Zavis Zavodni

An overland conveyor was constructed at a surface coal mine to reduce the truck haul distance and make the operation more efficient. An important element in this system is a truck dump facility to transfer coal from truck to conveyor. Mechanically stabilized earth retaining walls were employed to accommodate the coal processing equipment, including the crusher, in this facility. These retaining walls are close enough to the pits being mined that blasting induced vibrations must be considered in analyses of the wall structural stability.

Jan 1, 2010

By Pierre-Alexandre Abeel, Charles Dowding, Justin Lueker

When blasting is eliminated as a cause of cosmetic cracking, often someone will ask, “If blasting didn’t cause the crack, then what did?” This paper describes detection by remotely operated instrumentation of the new cosmetic crack that was climatologically-induced. The measurement was obtained as a part of the development of Autonomous Crack Measurement (ACM) instruments to measure micro-inch response of cracks to both long-term, climatological, and dynamic, blast vibration effects. The crack occurred in the wall of a structure that was monitored for over 29 months and as such represents one of the longest periods of ACM observation.

Jan 1, 2015

By Paul Worsey, Ron Ecklecamp, Scott G. Giltner, Ronnie Inman, Terry Drechsler

A blast monitoring program conducted at Chemical Lime Companys new lime calcining facility near Ste. Genevieve, Missouri is discussed. The purpose was to develop blasting criteria for the construction and operation of the lime plant within the quarry operated by Tower Rock Stone. Further, it was imperative to accommodate production requirements into the blasting criteria. The major concern was the effect of blasting on the curing of green concrete during the construction of the storage silos and kiln stacks. In addition to discussing the susceptibility of curing concrete to blast vibrations, the paper also details how this varies with time.

Jan 1, 1996

By Matias Suarez, Diego Zenteno

This paper is aimed to display the new advancements of blasting engineering done in different mining sites throughout the country, associated to electronic sequencing, energy of the explosive and its impact on the fragmented rock. This document explains how to define and implement selective sequencing in the blasting in order to promote the propagation of cracks, therefore impacting positively the productivity through the use of the LaGrange diagram. The LaGrange diagram is a very convenient and illustrative method to present the dynamic behavior associated with wave and crack propagation (Rossmanith. H, 2002).

Feb 1, 2020

By Matias Suarez, Diego Zenteno

It is known that the introduction of electronic timing in the sequencing of blasting has changed the vision and way in which mining is developed. It is possible to deal with more complex and sophisticated drilling designs, without compromising productivity or safety. It has been shown in various studies, that a correct timing of the blasting provides an improvement in the improvement of the processes downstream, due to a decrease in the resistance of the resulting fragments coming from the interaction of the waves generated in the detonation of explosive loads. On the other hand, it has also been shown that variations in the composition of a same type of explosive, has a significant influence over the resistance of the blasted material, also the energy associated to break it, affecting directly its degree of fragmentation. This paper is aimed to display the new advancements of blasting engineering done in different mining sites throughout the country, associated to electronic sequencing, energy of the explosive and its impact on the fragmented rock. This document explains how to define and implement selective sequencing in the blasting in order to promote the propagation of cracks, therefore impacting positively the productivity through the use of the LaGrange diagram. The LaGrange diagram is a very convenient and illustrative method to present the dynamic behavior associated with wave and crack propagation (Rossmanith. H, 2002). This study focused on the methodology of the formation and measurement of seismic pulses, through the rock massif. For this purpose, seismic pulses were acquired in the field and then, the different dynamic phases of the wave were molded mathematically, with the purpose of favoring the coupling between them.

By Scott G. Giltner, Alex Schwenk

An iron operation sought to extend the life of the mine by conducting a major pit pushback in an area close to several public structures and the neighboring town. The result of the pushback would make millions of tonnes of ore available for mining allowing many additional years of taconite mining. This paper discusses the initial development blasts conducted for the pit pushback. For the development blasts, it was determined that no fly rock should leave the mine site and that the blast vibrations should be as low as possible, but specifically under 19 mm/s (0.75 in/s) at a nearby sewage treatment plant. One issue complicating the blast design was the variation in hole depth within any given blast. For the initial sinking shot, the hole depths varied from 6.4 m (21 ft) to 12.5 m (41 ft). In the subsequent blasts the hole depths within each blast could vary up to 5.8 m (19 ft). Various tools were employed to design the blasts to ensure there was no fly rock and that the blast vibrations were as low as possible. UAV surveys of the blast areas were conducted to provide a 3-D representation of the free faces and bench surface. The 3-D point cloud produced from this was used to measure the shape of the free faces. Once the shape of the free faces was quantified, it was possible to establish proper placement of the crest holes and develop a custom explosive load for each blast hole. In addition, signature hole analysis was performed for each blast to determine the optimum delay time that balanced the need for minimal vibration, prevent fly rock, and a well fragmented muck pile. Electronic detonators were applied to achieve the necessary control of the blast that balances these three concerns. The results of the seven blasts conducted to date provided the desired results. The peak vibration level at the sewage treatment plant for the seven blasts was 10 mm/s (0.40 in/s). The only fly rock occurred when there was a miscommunication in the blast design resulting in under burdened holes on the front row. To date, the mine has been able to safely expand the pit into an area that will add many years to the mine life. The muck piles have been well fragmented with reports from the shovel that they have all dug well.

Jan 21, 2025

By Diego Quezada, Carlos Munoz, Marco Arellano

It is well-know that the presence of fine materials in mining has a direct impact on the plant processes with a great influence in the total amount of ore production and recovery. In Cu mining heap leaching is affected negatively by the presence of fines material (< 100 # Ty) in leaching piles, where a decreasing in Cu recovery is achieved in a lot of cases. D&B practices used normally in mine operations can generate fines > 4% in blasted piles, but the principal effects are reflected in the downstream processes where pre-conditioning post-blast materials release greater quantities of fines.

Jan 1, 2010

By Nan H. Lee, Christopher J. Hunter, Stephen H. Chung

Several factors affect the productivity of mining operations. The geological structure of a mineral deposit and the fragment size of blasted material are considered to be most influential. It is well known that productivity varies with mucking cycles and that this is related to the explosive energy produced by a blast.

Jan 1, 1991

By Oldrich Machacek, Gary R. Eck

The underwater detonation test method has been long recognized as a useful tool for the evaluation of the energy release and relative effectiveness of commercial explosives. In this study, underwater energy tests were performed for emulsion and watergel commercial explosives in comparison with ANFO. Heavy ANFO type blends based on emulsions and watergels were also investigated under and without confinement.

Jan 1, 1990

By Eduardo Lozano, Vilem Petr

This study demonstrates the ability of high-order, shock-capturing methods to simulate detonation wave propagation in right circular cylinders of non-ideal explosives. 2-D axisymmetric, reactive Euler equations were solved for the detonation of the highly non-ideal explosive ammonium nitrate-fuel oil (ANFO) using a simple pressure-dependent rate law and perfect gas equation of state. The fractional step method was applied to the convection and reaction operators using a 2nd-order Strang splitting. The flow solver consisted of a finite difference scheme where the flux is reconstructed by a modified fifth-order weighted essentially non-oscillatory (WENO5-Z) with local characteristic decomposition and local Lax-Friedrichs (LLF) flux splitting. Time integration was performed by a third order total variation diminishing (TVD) Runge-Kutta time discretization method, also known as the strong stability preserving (SSP) method

Jan 1, 2019

By B T. Lusk, John J. Silva Castro

The signature hole method uses a convolution operation to predict the waveform of a production blast based on the record of a waveform produced by a single blast hole. Convolution is a mathematical operation on two functions, (generally the product) to produce a third one. Recent research communication and publications highlight a lack of discussion in the literature about the available methodologies to calculate the convolution for blast vibration prediction. The goal of this paper is to discuss and present in detail for students in ground vibrations from blasting, several techniques to calculate the convolution between signals when the signature hole method is used. Convolution is a straightforward operation when signals produced by each hole are assumed the same, however; variations in the signals from each hole in a production blast require a more complex convolution operation. A graphical procedure is shown in this paper to solve a convolution when signals vary hole-to-hole (as expected in a mining production blast). The graphical methodology was tested using a recorded blast event and the results were compared to the regular mathematical procedure (convolution) and the results from a commercial software used in the mining industry. Results show that the graphical procedure is in agreement with the results from the other two.

Jan 1, 2014

By Earl C. Hutchison, John Loviza

At the Metropolitan Nashville International Airport, with its more than 600 scheduled daily flights from American Airlines hub operations, other scheduled airline flights, Tennessee Air National Guard operations, as well as numerous industry air flights, the excavation of 300,000 cubic yards of rock was required without disrupting airport operations for a cut and cover underground tunnel with a 4 lane US Highway and new airplane runway to extend across it's top. In addition to the excavation, the removed rock was to be broken to specification type that was clean and of small size for fill in another area of the airport property. The blasting was limited to two 1/2 hour windows per day and stiff monetary penalties were in place for schedule slippage of each phase of the project.

Jan 1, 1992

By Gordon F. 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 often complex, particularly when risks are high.

Jan 1, 2002

By B Mohanty

The current basis for rating of commercial explosives is examined, with particular emphasis on calculated bulk and weight strengths, detonation velocity and underwater energy measurement. The calculated strengths still form the basis for selecting explosives for most blasting applications, with the measured detonation parameters serving only as a measure of the quality of the explosive. The major drawbacks with this approach are discussed, in view of the non-ideal nature of commercial explosives and the field conditions prevalent during the blasting operation. A unified approach to rating explosives on the basis of blasting performance rather than calculated energy alone is presented for various types of explosives. This incorporates the relevant field parameters as well as the effect of non-ideal reactions, both of which affect explosive energy release and its transfer to target rock.

Jan 1, 1988

By Andrew P. Ritter, James W. Reil, Douglas A. Anderson, Stephen R. Winzer

We have developed a method for predicting and controlling ground vibration from blasting using a rigorous scientific approach. The method is based upon the superposition of seismic waveforms generated by a single-hole free-face shot, recorded at seismographs deployed in an array that includes environmentally sensitlve locations. Waveforms generated by single-hole shots are shown to be reproducible. The waveforms for each of the sites are used to construct synthetic seismograms for delayed shots based upon linear superposition. A computer code systematically constructs the seismograms for the delayed shots, with incremental delays between holes of 1, 2, or 3 milliseconds (ms). A Fourier amplitude specs-rum is calculated for each synthetic seismogram and the spectra are plotted on a map in delay-frequency space, i.e., each row of the map represents the Fourier spectrum for a blast with a particular delay interval. For single-row shots, the delay between holes in a row is used; for multiple-row shots, the delay between holes In a row is kept constant and the delay between rows is incremented. Predicted vibration varies strongly as a function of delay and h

Jan 1, 1985

By Thomas R. Scotese, John L. Ackerman

The Hanging Lake Tunnel Project represents a major portion of the Glenwood Canyon Project, the last piece of Interstate 70 to be constructed. The project features twin bore, large span rock tunnels and six open cut portal excavations, all excavated by drilling and blasting. This paper presents descriptions of the methods used by the Owner and Engineer to control and monitor the drilling and blasting practices in the tunnels and in the portal areas.

Jan 1, 1992

By Satish R. Kate

Explosive is a chemical energy, which on detonation is released instantaneously with extremely high speed and under high pressure. It is used to meet the basic requirement for breaking of rocks. The productivity is the function of Drilling, Explosives and Fragmentation. Thus, the quality of explosives (energy content) is the key to get desired fragmentation. The variation in energy of explosives and volume of rock per hole have direct impact on fragmentation and cost of excavation (drilling and explosive costs). With the application of higher and higher energy content explosives, it is possible to expand the drilling patterns, i.e. volume in cum. per borehole. As such, higher drill productivity and higher production from the given number of holes can be achieved by adopting appropriate energy content in explosives, and suitable drill pattern for getting desired fragmentation.

Jan 1, 1998

By J S. Brower

Disposing of the AMDP-1, Jackup drilling rig in the Arabian Gulf.

Jan 1, 1978

By M. Szumny, P. Mertuszka, K. Fuławka

Multi-face destress blasting is the basic method of reducing rock bursts hazard in Polish copper mines. Blasting operations of this type are carried out regularly, twice a day in order to minimize the geomechanical threat while maintaining high extraction efficiency. Unfortunately, the assessment of the effectiveness of this type of work until recently was based solely on determining whether a given destress blasting triggered a seismic tremor or not. Information on the characteristics of seismic waves generated by blasting has so far been omitted in analyzes of this type. The lack of reliable knowledge about the generated seismic effect makes the introduction of constructive corrective actions impossible, which in turn significantly reduces the triggering potential of conducted destress blasting. This study presents the results of comprehensive work aimed at increasing the effectiveness of active rock burst prevention in Lubin underground copper mine. For this purpose, an innovative system for continuous monitoring of seismic waves induced by multi-face blasting was developed, and a new method for seismic assessment of the effectiveness of the destress activities was developed. Based on the monitoring data and the comprehensive analysis of waveforms, the effectiveness of individual blasting operations was determined, and on this basis, modifications to the drilling and blasting patterns aimed at increasing the generated seismic effect were proposed. The use of innovative methods of monitoring and data analysis made it possible to increase the effectiveness of the conducted activities, in terms of the magnitude of seismic vibrations, up to 250%. It should be emphasized that the introduced modifications were aimed at increasing the effectiveness of blasting operations while maintaining the current level of costs. As a result, the proposed solution turned out to be highly effective, significantly affecting the safety of the work carried out in Polish copper mines. Thus the proposed approach is planned to be implemented in other Polish copper mines belonging to KGHM in the near future

Jan 1, 2024