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By S. Kevin McNeil, William Joa, Catherine Johnson, S. Omar Garcia

The geometry of an explosive is known to have a fundamental effect on the resulting shock wave propagation. Typically researchers use a spherical or hemispherical geometry in order to simplify the shock wave so that resultant overpressure and impulse are uniform in all directions. The goal of this research is to understand the overpressure characteristics from a sheet explosive, a geometry often utilized for breeching in the military. In training alone, soldiers can be exposed to several tests per day, which may be contributing to the prevalence of blast induced mild traumatic brain injuries. Using PCB pressure transducers and high speed video, it was found that as the angle departed from normal (perpendicular) to the face of the sheet explosive, the over pressure decreased significantly. When in line with the plane, a decrease of over pressure by as much as 20% was observed. Time of arrival was roughly 20% faster directly in front of the charge with a pressure amplification of 46% relative to a spherical baseline charge of the same mass. This testing may reveal a more complete relationship between the pressure and angle from the explosive that could have applications for military and law enforcement with respect to best practices on blaster location for reduced over pressure exposure.

Jan 1, 2019

By Xiaoning Yang, C David Pearson, Brian W. Stump

An experimental study of ground motion from explosions designed to remove overburden in an open pit coal mine is reported. The purpose of this study is a characterization of these ground motions in the distance range of several tens of meters to several kilometers. The investigation has focused upon both single cylindrical sources with different explosive configurations as well as arrays of charges in the production mode. Critical to this study of source configuration and coupling is experimental control of the individual explosions, the timing of the explosions and the geological properties. The height of the explosive charges, their depth and charge distribution were monitored in the field. High speed photography as well as velocity of detonation measurements were made on the multiple explosion source so that detonation of individual charges could be documented.

Jan 1, 1994

By R. Reed Skaggs, William Gault, Douglas Kooker

Both armored personnel carriers and light combat vehicles are increasingly vulnerable to a variety of highly lethal antitank land mines. As a result, there is a need for modeling and understanding the interaction of mine blast products with respect to the resulting loading and damage mechanisms inflicted by explosive blast and impact on vehicle structures. However, the mechanics of blast soil interactions are still poorly understood. The objective of this investigation is to computationally simulate a series of experimental buried mine explosions in saturated sand soil -- over a wide range of scale – and compare the predictions of blast loading to data. Small scale tests have recently been conducted at the University of Maryland with a few grams of RDX acting against an aluminum plate, while recent full-scale tests at ARL involve several kilograms of TNT against 12,500 kg of RHA. The ARL measurements reported here are based on the Vertical Impulse Measurement Fixture (VIMF) facility, a structural mechanical device that responds to blast loading by measuring the vertical displacement of a fixed mass vertical guide rail, which is a direct measure of the imparted impulse. CTH predictions for vertical momentum of the target plate are within 60 – 80 % of the reported impulse data for this wide ranging set of tests. One of the comparisons, however, suggests that the TNT charge in a particular VIMF test may not have fully reacted.

Jan 1, 2005

To meet the energy requirements, hydroelectric projects are planned and executed in many countries. Though these projects requires a high capital investment, the returns are regular with minimum maintenance after commissioning of the project and are ecofriendly. Bhutan is situated in the eastern Himalayas and covers an area of 38,394km2 (14824.01sq. miles. It is bordered by India in East, South and West and by Tibet in the North. The hydropower potential of the country is estimated at 30,000MW, out of which around 5% has been harnessed.

Jan 1, 2016

By Robert B. Hopler

Emplacing explosives in the borehole by bulk methods is utilized today for about 35% of all of the explosives used in the United States. Although different from today's methods, some bulk emplacement has been utilized throughout the history of explosives. This paper provides an overview of the evolution of the industry from primarily packaged to primarily bulk materials and methods.

Jan 1, 1992

By Pefer F. Stacey

This paper considers some of the trends in slope design technology that are emerging as we approach the 21st Century. While the ability to design stable slopes has unproved greatly over the past 20 years, trends towards steep short-term slopes for small highgrade orebodies, and very high slopes for mega-pits centered on low grade deposits are starting to indicate limitations in available technology.

Jan 1, 1994

By Mike Higgins

"Data management is emerging as a major concern for miners. Engineers today are faced with anextensive array of data from varying sources, and are required to consolidate and analyse thisinformation to produce an effective and efficient mine plan. The viability of a mining operation canbe dependent on the outcomes of this process. With so much at stake, it is no surprise that mostengineers prefer a standard approach to blasting which is designed to minimise risk rather thanoptimise performance."

Jan 1, 1998

By Jaki Wilson, Les Armstrong, Neville T. Moxon

Low shock energy ANFO (ANFO) mixtures have been developed for use in fragmenting weak overburden materials and reducing damage.outside the blast zone in dry conditions. These mixtures can be readily produced on a minesite using conventional equipment and are formed by mixing low density additives such as polystyrene, bagasse and sawdust with ANFO.

Jan 1, 1990

By A. Feldman

Measuring dynamic effects on existing structures such as dams and bridges during earthquakes or blasting is frequently done using strong motion detectors. However, a more comprehensive dynamic structural evaluation requires direct measurement of deflection, strain, and pressure changes during dynamic events. Many existing structures have vibrating wire gages already installed that can be used with modifications to the data acquisition systems to provide direct measurement of dynamic displacement, strain, and pressure. The project described in this paper provided the opportunity to demonstrate the feasibility of using vibrating wire technology to measure dynamic effects on existing structures.

Jan 1, 2006

By Brian Wingfield, Greg Williams, Richard W. Givens

Application of required energies into the rig design can have a dramatic impact upon productivity. Computer modeling of these production variables has led to changes in design with values closely approaching actual field data. Knowledge of these required energies can also specify the proper drilling technique to the application. With this knowledge, productivity-to-cost ratios can be determined with the most efficient option chosen.

Jan 1, 1995

By Martti Hagfors

The Finnish Defence Forces Technical Research Centre (PVTT) studied the effect of shape of boost-er to its ability to ignite insensitive (IM) plastic bonded explosive (PBX). Therefore an explosive fac-tory produced 20 insensitive (IM) plastic bonded explosive (PBX) charges for the tests. The mass of each of the charges was exactly 9.2 kg (20.3 lb). The charges were equipped by two different type of boosters; RDX and PETN. Both the explosives contained some parts of plasticizers. The weight of all the boosters was exactly 300 g (0.66lb). On the bases of their shape, the boosters were also divid-ed into two different groups, cylindrical and “pancake”. In the middle of the “pancakes” there was also shaped a small cone in such away that the detonation could accelerate to its full speed after the charge was ignited. The following shots were exploded;

Jan 1, 2013

By G. R. Adhikari

Step 4: Selection of explosives and initiation system Various types of explosives are manufactured in India and a wide choice is available among them that include nitroglycerin based explosives, slurries, emulsions, ANFO (ammonium nitrate mixed with fuel oil) and heavy ANFO. The choice is also available between cartridged and bulk loading systems. In Indian mines, much importance is unduly given to the cost of explosives alone which is not conducive to optimization of blast design parameters. The concept of energy per meter of blasthole and the way in which the total explosive energy is partitioned between shock and heave is not considered in the prevailing practices. Besides, very little efforts are made to objectively evaluate the performance of explosives for a given site condition. Tailoring explosives is limited to changing the density of the bulk explosives. Cartridged explosives are still being extensively used in large operations where bulk explosives should be the preferred choice.

Jan 1, 2002

By Rudi Toba

Several areas at the DOZ haulage were observed for the crusher’s location. Initially the new crusher designed position was west of the crusher 1, but due to concerns of the mine crack zone (deep MLZ) the crusher position moved to the south. The new crusher location is situated in a diorite rock massive between 3053 – 3079 levels, with the overall excavation of 2500 cum and dimension of 14m long, 14 m wide and 14 m high. Main Crusher chamber itself excavated by development jumbo in three lifts. Development of access to the bottom crusher was developing the same time as chambering the top crusher. The pocket of the crusher mined with vertical crater retreat system which is initiated in one time after middle slot raise. Collaboration between production and perimeter blast holes to be obtaining in control the actual cuts as per the design shape.

Jan 1, 2007

By Des Bolton

With the introduction of Cast Blasting techniques, field controls of Drilling & Blasting operations became more important. New drills were purchased which were equipped with sophisticated instrumentation and more accurate drilling plans were required. Concurrently a decision had to be made on the replacement of borehole logging equipment owned by the mine. The use of a contractor to log blast boreholes was eventually decided upon, the information gained from this operation is used in the short-term drill and blast planning and may also be used to assist in the coaling operation if density I quality correlations prove acceptable.

Jan 1, 1994

By Douglas Bartley, Robert McClure

This paper discusses the advances in programmable, testable high accuracy electronic detonator technology. The operation and safety of electronic detonator systems are required to meet rigid safety standards and withstand the demanding environment of in-field applications. These requirements are discussed through comments on existing safety requirements in Europe.

Jan 1, 2000

By Qi Shifu, Guo Tao, Liu Haoquan, Yao Chaogui, Zheng Li

Abstract: To excavate oil-gas pipeline ditches in a rocky region or area the explosive method is needed. When a parallel ditch is to be dug by blasting near or in the vicinity of an existing pipeline, a safe criterion must be determined to ensure safety for the latter. In this investigation, with the construction of the second phase of the West-East Gas Pipeline Project, we carried out real blasting tests and numerical simulations to explore the safety criteria for the existing pipeline. Through this investigation, we obtained the safe strain elasticity threshold es2000µe, blast vibration velocity calculation formula, and the maximum vibration velocity Vmax=14cm/s(5.51in./s) for the pipe under blast shock loading, and worked out how to determine the charge size in the follow-up blasting excavation. These results can be used to determine the maximum explosive weight per delay and decide delays for the initiation circuit network in blasting a parallel pipeline ditch, and to make safety assessments for the existing pipeline in service. Having successfully been applied in the second and third phases of the West-East Gas Pipeline Project, China-Russia Oil Pipeline Project and China-Myanmar Gas Pipeline Project, these findings are very significant for other similar pipeline construction.

Jan 1, 2014

By Dale Preece, Stephen Chung

Blasting induced rock fragmentation is an art that has been developed and refined for hundred’s of years through blasting and recording the results. Good blasting fragmentation practices were thus developed through experience. However, this method requires a history that is typically developed in a mine over a number of years and sometimes at considerable expense. Quantification of fragmentation as a function of rock-mass characteristics and blast design is attractive. Developments towards this end have included semi-empirical methods as well as computer codes that explicitly treat shock wave transmission and the subsequent rock breakage. This paper will present predictions of fragmentation resulting from rock blasting using the computer code AUTODYN and a new state-of-the-art material model for brittle rock and concrete.

Jan 1, 2003

By Tristan Worsey, Nathan Rouse

Florida legislature allocated funding for the Florida State Fire Marshal to review the applicability of the United States Bureau of Mines (USBM) Report of Investigations (RI) 8507 blast vibration limits with respect to Florida and its soils. The study also discusses whether the current blasting vibration limits set by statute are still appropriate, including a review of measured vibration amplitudes and frequencies, structure responses, and theoretical analyses of material strength and strains.

Jan 1, 2019

By Ronald L. Cocklin, Vivian Patz

Blasting techniques are becoming increasingly sophisticated as the need for improving mining efficiency grows. One of the areas of blasting that has never been fully exploited, due to a lack of a control and reliability, is the initiation of explosives. Expert Explosives have taken on the challenge to not only provide an initiation system that offers control and reliability, but also provide benefits that are critical to enhanced mining productivity. These benefits can only be delivered through the medium of electronics and computer controlled systems.

Jan 1, 1995

By Michael Wieland

For shooting rock properly, some relatively fixed quantity of rock work is required from the total charge mass, while keeping the overall toxic fumes to a minimum. The overall fumes weighted for the toxicity of different species and taken per unit charge mass, ??, are represented by a relative fume toxicity (RFT) formula. The worst two contributions are often carbon monoxide {CO} and total nitrogen oxides {NOX}, so the traditional Russian formula RFT-R formula suffices, though a generalized form RFT-G with more terms is worth checking. Using the work-principle model from thermodynamics, the rock work per unit charge mass, ??, is found from the reduction in internal energy for the reaction zone. This resolution technique for rock-work invokes the usual assumption that the quick irreversible process occurs without notable heat transfer to the rock (adiabatic); rock-work is not resolved, when this restriction is untenable. The ratio of ?? to ?? yields the weighted toxic fumes divided by the rock work or the readjusted fume toxicity ??, where ?? = ??/??. For convenience, graphical trends of ??, ?? and ?? were normalized using reference results for a stoichiometric (ANFO) mixture of ammonium nitrate (AN) and fuel oil (FO) shot under nominal rock confinement, noted later.

Jan 1, 2006