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By Claude Cunningham, Szendrei

The partitioning of blasting energy into “Shock” and “Heave” components is a popular concept for attempting to match explosives to particular ground conditions and blasting results. The issue is complex, as it affects both the detonation process and the immediate response of the rock skin. However, the fundamental process of energy transfer from the explosive to the rock through the blasthole wall is not well defined. Clues to the “Shock” phase of blasthole expansion are given by cratering behaviour of materials subject to high velocity penetrators. The final cavity volume defines both the energy used to achieve this and the resistance of the confining material. Attention is being given to the link between penetration of a solid target and expansion of a readymade hole, both producing the same outcome. The benefit of this work is that it leads to clearer understanding of how explosives will impact upon the blasting results and helps to explain the energy consumption in blasting.

Jan 1, 2004

By Harry Verakis, Thomas Lobb

This paper summarizes the course of mine blasting safety, particularly in underground coal mining, in the USA for over a century of mining operations. During the late 1800's and especially in the first decade of the 1900's, a large number of mine explosions occurred in which blasting played a significant role. A contributor to the large number of mine explosions during this time period was the use of black blasting powder to extract coal and other minerals. A review is made of some of the more significant underground coal mine explosions that resulted from blasting operations during this time period up to the present day. The safety measures that were adopted and required by a series of laws as a result of mine explosion disasters in which blasting was one of the factors are examined. The time line of historical improvements in blasting safety and the tremendous reduction in fatalities and injuries over a century is illustrated and discussed. The improvements, which included the elimination of black powder and dynamite and the introduction of safer explosives termed "permissibles" occurred slowly over time and culminated from the occurrence of many coal mine explosion disasters. The blasting accident history over the past decade is discussed to show the great gains made when compared to the first decade of the 1900's. The most recent blasting accident fatality that occurred in October 2006 at a U.S. underground coal mine is also discussed. Although the blasting accident record is significantly improved from over a century ago, continual improvement is needed to reach the goal of zero fatalities.

Jan 1, 2009

By Alan Minchinton, Ian Kirby, Jim Chan

It has long been known that successful blasting in soft and hard rock can require the use of different explosives. While choosing an explosive of the right energy density is important, the dynamics associated with non-ideal detonation behaviour play an equally major role. Tuning the energy release rate of an explosive to optimise its blast efficiency can be likened to tuning an internal combustion engine to improve its performance.

Jan 1, 2014

By David Nemir, Jan Beck

A challenge in materials science is the production of a bulk solid material from a powder precursor. One solution is to use shockwave consolidation whereby a ductile tube is loaded with the powder of interest and then surrounded by an explosive. A detonator at the top of the explosive column initiates a symmetrical high-pressure pulse that moves inward and down the tube, causing the tube to deform and the interior powders to consolidate into a dense, well bonded bulk material.

Jan 1, 2016

By Allan King

Ammonium Nitrate (AN) is most commonly encountered as either a prilled solid or a highly concentrated aqueous solution, with or without organic ( e.g amine) nitrates. Under certain conditions of fire exposure involving prilled or solid AN, the molten state can be formed. The shock sensitivity of the molten material at temperatures greater than 220 Celsius has been found to be much higher than that of the prilled or solid form. Molten AN can be a precursor to events leading up to explosion of a bulk prill storage pile as a result of fire exposure. The explosion hazards presented by molten AN are a function of two factors; 1) its shock sensitivity and the deflagration to detonation ( DDT ) properties of the molten material, and: 2) the ability of large masses of unfueled prilled AN to be initiated and detonate. This paper presents the results of tests designed to determine the shock initiation and DDT properties of the solid ( prilled ) and molten AN.

Jan 1, 2008

By P J. Dailey, S L. Burchell, R F. Chiappetta

High-speed motion picture photography and its application to the mining, quarry, construction, and explosive industries has proven to be a valuable diagnostic tool. The techniques developed allow one to evaluate blasting performance, compare explosive efficiencies in relation to burden velocity, and estimate optimum delay times to provide adequate forward relief.

Jan 1, 1983

By James Goldberg, Sally Zadra, Wiliam Reisz

Early recognition and risk assessment is critical to sustaining a safe and productive blasting operation. While every blasting environment holds inherent risk, highwall blasting in highly congested areas such as Hanson Material Service Corporation’s Romeoville and Thornton quarries in the greater south Chicago metropolitan area can be particularly perilous

Jan 1, 2008

By Eric Grigoryan, Wade Hutchison

An engineering study of 2,250 blasting damage claims from 1999 to 2008 in Tennessee, Kentucky, Virginia, Nevada, California, Georgia, South Carolina, North Carolina, Alabama, Arizona and Utah were investigated over the last decade and these investigations determine that blasting ground vibrations damage claims are valid less than 1.3 percent of the time. This study determined that valid blasting damage occurred as a result of impact damage associated with fly rock, air concussion stressing, instantaneous reverse stressing associated with ground vibration and crater zone soil shifting related stressing.

Jan 1, 2009

By Frank Hirthammer

Over the past few years, development and implementation of digital logistics solutions has convinced users of many additional advantages of this technology. Barcode labeling and reading increases the company’s efficiency and safety by reducing handwritten documentation and preventing misinformation. Sustainable information and productivity management is a significant advantage in competition. Since manufacturing information is tracked throughout the whole supply chain until the final consumer, all processes become transparent what ensures efficient risk tracking, correct disclosure to authorities (if required), and the compliance with company rules.

Jan 1, 2018

By Leslie Taylor, Uli Leiste

In this paper, results from small scale testing conducted to determine pressure time profi les acting on a plate (taken to represent the bottom of a vehicle) at any given distance from the center of the plate will be presented. These results will be discussed in relation to visual observations of the upward moving sand.

Jan 1, 2008

By Robert B. Hopler

The history of bulk loaded explosives begins with the loading of black powder and RRP (Railroad Powder) into vertical boreholes. The early air place, net of black powder and nitrostarch dynamites is covered, as are the brands and formulas of the nitroglycerinsensitized "Bagged" powders.

Jan 1, 1993

By Eddie L. Catbagan

The Escalante silver-bearing deposit, consisting of a relatively wide and continuous quartz vein, contains openings ranging from minute to a few feet wide on the footwall and hanging wall. These openings (water courses or vug holes) are I believed to have been created by the fluctuation of the water table.

Jan 1, 1983

By Yannick Bleuzen, Manuel Joao, Frederic Monath, Miguel Quaresma

The N1 Porto tunnel project is a 650m segment of large-scale civil engineering plan to improve traffic flow between Porto’s downtown district, the Santo Antonio hospital district and the highway access. The tunnel is being excavated into a massive “Granito do Porto” granite structure, 4 – 20m below a highly urbanized environment of Porto, Portugal. The project was originally started in 2000 and was stopped due to the inability to mechanically excavate the granite rock. The city of Porto engineers then turned to traditional drilling and blasting techniques. The use of pyrotechnical delay detonators did not easily comply with the specified environmental and safety requirements concerning blast charging, firing and vibration control resulting in the process taking far too much time. The introduction of digital blasting was proposed to overcome these concerns.

Jan 1, 2005

By D Maxwell Ellett

This report presents an evaluation of knowledge concerning a process used in predicting ground motion resulting from large scale conventional explosive detonations, The shots were set off in Arizona in connection with copper ore recovery activities.

Jan 1, 1976

By J R. Hearst, T R. Butkovich

Explosive-induced fracturing and permeability enhancement far from a free face were studied. A one-dimensional computer program, SOC, was used to predict the total failure-associated distortional strain, ef. Laboratory and field experiments associated the calculated ef with the observed fracture and permeability enhancement. An ef value of 0.015 corresponded to the observed radius of effect, which was about seven times the cavity radius and was consistent with predictions from SOC and from the literature.

Jan 1, 1976

By Peter Cameron, Tom BoBo

Comminution, being the energy intensive part of a mining operation receives much scrutiny by cost controllers, CEO’s, investors and others as the mining industry goes “back to basics” to reverse the decline in productivity which occurred during the mining super cycle.

Jan 1, 2019

By Carlos Pañura, Michael Geldres, Alejandro Rojas

In this current era of production in large volumes of surface mining, which demands the realization of large-scale blasting, the mining industry must deal with the impact of the vibrations generated by the detonations that are carried out daily in the mines. In this context, the need arises to minimize and control the impact produced by vibrations by determining the interference times of each generated vibration waveform. The vibration waves are produced by the detonation of the explosive charges of each blasthole, analyzing the vibration waves produced by each blasthole, allow us to determine the optimal time between the detonation of each blasthole to reduce the vibrations of the production shot. Once the optimal time is found, it is possible also, to predict the vibration of the production shot (considering times and sequences) using predictive models. The waveform recorded includes information regarding the particle velocity and the dominant frequencies of the vibration. To determine the time between holes, a graph was constructed with the values of the vector Sum VPP (m / s) vs Time between blastholes (s), once the time between blastholes “t” was found, the simulation of the output sequences continued in such a way that, by adding the single waves generated by the blasthole, it gave us a record of vibrations with the lowest level of vibrations.

By Yves Lizotte, Malcom Scoble, Sanu Hanspal

"This paper reviews the physical, chemical and mechanical components of what is considered to be the anatomy of a blast muckpile. These relate principally to geometry, floor, fragment size and shapedistribution, density, hydrology, weathering, and diggabiity characteristics."

Jan 1, 1995

By Sterling Ziegler, Kameron Ray

Mining operations at a Wyoming coal mine were progressing to within 300 feet (91 meters) of a high pressure natural gas pipeline. Vibration levels from cast blasting were at a point at which standard designs would exceed permitted limits and could potentially damage the pipeline. Without a confident vibration model, mining would be unable to continue in the pit rendering an entire cut of otherwise mineable coal sterile. To safely blast in the area, linear superposition seedwave analysis techniques were attempted to be used to create a model that could accurately predict the vibration at the pipeline. Four signature holes were fired individually. The four signature waveforms were monitored at eight discrete locations to create thirty-two vibration data points. Two of the monitors were equipped with triggers enabling the calculation of p-wave velocity.

Jan 1, 2018

By D Wilson, E Nagy, R A. Augsten, R R. Vandebeek, R L. Guilbeault

The Canadian Explosives Research Laboratory (CERL), is evaluating the status of the Schedule IV explosives container as it presently pertains to the industry. The Schedule IV container serves the same purpose in Canada as the IME 22 container does in the United States. That is, to transport detonators on the same vehicle which is carrying explosives.

Jan 1, 1990