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By Thomas M. Keevin, Gregory L. Hempen, David J. Schaeffer

In an attempt to reduce the potential for fish mortality during the explosive demolition of Locks and Dam 26, Mississippi River, the U.S. Army Corps of Engineers, St. Louis District explored the use of a bubble curtain to reduce the fish kill radius of underwater explosions. Bubble curtains are walls of bubbles rising from a bottom-resting bubbler manifold supplied with compressed air. Demolition engineers have long been aware of the attenuating properties of air bubbles in water. As such, air curtains have been routinely used to protect underwater structures from damage by underwater explosive shock waves. However, their use in protecting aquatic resources during full-scale explosive demolition projects was untested.

Jan 1, 1997

By M Scoble, J Szymans

During the past year, the Canadian Centre for Automation and Robotics in Mining (CCARM), McGill University, Montreal, has been involved with INCO Ltd.'s Manitoba Division in investigating the extent and mechanisms of blasthole deviation. Drilling accuracy can well be regarded as perhaps the single greatest "controllable" factor influencing dilution in INCO's open sloping operations. As INCO and other underground mines seek to minimize dilution, while attempting to maximize productivity, issues of drilling accuracy become increasingly significant. It is important therefore, that means exist by which true blasthole trajectories can be determined, so that if needed, modifications to hole loading instructions or redrilling of holes can be ordered, thus avoiding poor blast results.

Jan 1, 1991

By Bill Bauet, John Anderson

There are always security concerns when explosives are transported and stored, and these concerns are intensified in peacekeeping operations where explosives could fall into the wrong hands. MREL Specialty Explosive Products Limited has developed FIXORTM, a new approach to neutralizing landmines and unexploded ordnance (UXO). The product consists of two precursors: a flammable liquid in one plastic container and a totally inert powder in another; neither of these precursors is classified as explosives. Both precursors are approved for transport by land, sea and commercial passenger airfreight. The precursors are mixed to form an explosive immediately prior to placement next to the UXO or landmine. Initiation is by blasting cap or detonating cord.

Jan 1, 2001

By S C. Alford

Explosive fracturing of metal is usually considered to be an imprecise process but, by careful consideration of shock-wave geometry, precise results are obtainable. The limited development of such charges is attributed to experimental difficulties. A charge configuration has now been devised in which a prismatic wave-shaping element is used to resolve the shock-waves entering a target plate into two convergent components. The extreme pressure caused by their collision initiates a diamond fracture in the proximal target face, and coincidence of reflected tension waves generates a fracture in the distal face. A combination of these effects breaks the target. An embodiment of S.R.T. is described which is flexible, magnetic and contains no cavities.

Jan 1, 1986

By Q Liu, P D. Katsabanis

The energy output of crushed AN/FO, crushed AN/FO mixed with Aluminum (5%, 6.4% and 9.4% A1 by mass) and a commercial emulsion explosive has been measured using a detonation calorimeter. The charges had a diameter of 10 mm and were heavily confined by a 11 mm thick copper shell. In order to achieve stable detonation glass microballoons were used in the explosives so that the density of the AN/FO charges would be around 1.1 g/cc. The charges were detonated in vacuum and the detonation products were analyzed using gas chromatography. It was found that energy values were very close to calculated values obtained by ideal detonation codes.

Jan 1, 1993

By John J. Ridgeway

Habits take us where we were yesterday and attitudes tend to keep us there. Until recently, little had been accomplished to improve conventional explosive energy for use offshore. But with the special requirements of the Offshore Oil Industry, and particularly in the North Sea, most equipment, products and services must be specialized as well. Previous attempts to excavate a trench for a sealine in surf areas had been impossible to accomplish. But with the application of safe, controlled explosive energy, an impossible task to accomplish yesterday has now become a reality. Explosive energy, often overlooked as a convenient and economical offshore tool, excavated a clean trench underwater for a 40" sealine at Djeno in the African Congo recently.

Jan 1, 1977

By A. Cobbii, M. Kasliki, W. Birchi

The Department of Mining and Mineral Engineering at the University of Leeds has a long history of research into the environmental impacts of blasting from quarries and opencast mines. This paper gives an outline of a detailed case study into the structural damaged induced in a rock walled tunnel with a brick lined crown due to close proximity quarry blasting. The test site Taffs Well Quarry is located in South Wales in The United Kingdom and has a disused railway tunnel situated within the south eastern comer of the quarry site. Quarry development plans included the working of this area and therefore the deliberate destruction of the central section of the tunnel.

Jan 1, 2001

By Jaime Huidobro, Mervin Austin

The effect on an explosive column of the sharp transient stress waves generated during the earlier detonation of adjacent blastholes is of paramount importance to explosives users. Some explosives will sympathetically detonate under these stresses. Others may suffer a transient desensitization, arising from a temporary increase in the density of an explosive beyond certain limits and persisting until the explosive mass relaxes back to the original density. Some explosives are so adversely affected by these stresses that the product suffers immediate and permanent loss of sensitivity. These effects can be clearly seen while blasting in tough conditions such as burn cuts or wedge cuts and in materials, such as coals, that propagate shock waves well.

Jan 1, 1992

By Philip M. E Thomas

For over sixty years man has struggled to defeat the natural swamp lands known as the Florida Everglades as demand for land to support the burgeoning population growth in the state continued almost unchecked. Over the past ten years there has been a growing awareness that this land development could wipe out a whole ecosystem in a very short time unless steps were taken to reverse the trends. In 1991, a state law called the Marjory Stoneman Douglas Everglades Protection Act was enacted giving power to the South Florida Water Management Board to condemn certain lands for conversion to manmade swamp lands, designed to filter polluting run-off water from the agricultural lands around Lake Ockeechobee.

Jan 1, 1994

By Ulrich Leiste, Andrew Wardlaw, William Fourney

This paper describes the loading on a plate suspended directly over an explosive charge submerged in water. This problem is of interest because it yields results similar to those obtained in the detonation of an explosive buried in saturated soil and thus it is associated with landmines. Recent experiments [1] indicate that plate loading from a submerged charge is similar to that for a buried one, with respect to impulse and pressure. Compared to the buried explosive problem, the submerged explosive case is attractive from a computational point of view; it replaces sand, which is diffi cult to simulate, with water, whose properties are well known. Studying this problem allows modeling uncertainties to be separated from sand simulation issues.

Jan 1, 2008

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 Scott G. Giltner, Terry Millar, Ben Bringhurst

"Kennecott Utah Copper (KUC) Smelter scheduled a rebuild of their flash smelting furnace forSeptember, 2014. KUC’s goal in this project was to reduce the rebuild time from 65 to 55 days by using explosives to break the matte and brick layers of the uptake shaft and hearth sections of the furnace. Previous rebuilds had employed the slower technique of mechanical breakers to remove the matte and brick layers which took 22 days. KUC has many years of experience in removing slag from the uptake shaft, but they had never used explosives to remove the hearth. As far as KUC was aware, no other smelter operation had attempted a hearth removal in this way."

Jan 1, 2016

By Paul McAnuff, Alastair Grogan

In Canada, the only vibration regulations which apply across the entire country are intended to protect fish spawning areas. The Provinces and Territories regulate mines and quarries, and are responsible for setting vibration and airblast regulations. Some Provinces have set specific regulations, while others leave these restrictions to the mines inspectors who can set limits on a case by case basis. For the most part, it is left to individual municipalities to regulate blast vibrations and airblast from other blasting activities, which differ from jurisdiction to jurisdiction, and in some cases are not enforced. Blasters working in different jurisdictions have to be aware of the applicable regulations for the area they are working.

Jan 1, 2005

By Jeff Senules, Oana Meins, Catherine Aimone-Martin, Scott Lanker, Brent Meins

Global wall strains from 4 to 77 micro-strains were measured at three structures adjacent to a highly-confined Florida quarry blast when PPV amplitudes ranged up to 6.05 in/s. Increasing the peak zero-crossing frequencies with carefully control delay timing helped to lower ground displacements affecting wall strains.

Feb 1, 2020

By Deepak Vidyarthi

This paper deals with various measures adopted in protecting a conveyor duct (named after a Conveyor Belt that was numbered as ‘02’) housing a 1600 mm (63 inches) belt conveyor system in a large, heavily mechanized open cast iron ore mine, producing about 20.0 million tones of ore per annum.

Jan 1, 2008

By Gary Kahn

In this document the VODR is discussed from a technical point of view and is intended to give the reader a feel for the design of the instrument, its technical specifications, and its limitations. It is not intended as a tutorial on the use of the instrument in the field.

Jan 1, 1989

By S R. "Bob" Pilshaw

Productivity is the popular "buzz" word that catches the attention of most managers when it is featured in the more popular mining and construction magazines. Engineering Task Forces and teams are formed to take advantage of productivity opportunities in almost all phases of an operation except the drilling and blasting area.

Jan 1, 1988

By Robert M. Carland, Horace Gene Biggs, David Holland

At a North Carolina feldspar surface mine, the orebody contains intrusions of waste material occurring at various angles from horizontal to dipping, and varying considerably in thickness. In order to obtain optimum feed for the mill, it is desirable to obtain maximum separation of ore from waste during blasting and digging.

Jan 1, 1990

By Jack C. Leader

The success of a blast using ANFO in wet boreholes is dependent on the quality of the bag the ANFO is packaged in. When a shot fails the dragline may stop and expensive redrilling may be necessary. The total loss to the mining operation can be hundreds-of-thousands-of-dollars.

Jan 1, 1981

By Wang Hao

"Demolition of reinforced concrete frame structures in building crowded cities is a hardproblem in control blasting. Any mistakes, e.g. wrong toppling direction of multi-storeybuilding or incompleted blasting of structures will all cause terrible accidents.To demolishframe structures safely, various disciplines including structural mechanics, explosionmechanics, rock engineering, etc. are involved"

Jan 1, 1993