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By Roger Holmberg, Donald Jonson

The Swedish Standard SS 460 48 66, “Vibration and shock - guidance levels for blasting induced vibration limits”, is based on more than 50 years of experience from blasting close to structures and tunnels. The Swedish Standard gives a method for calculation of guidance values for different types of buildings and ground condition under the building. This is done for every building and structure within a predetermined zone. The guidance levels are for the peak particle velocity monitored in vertical direction. The standard is valid for all kinds of blasting project (tunnelling, quarrying, mining etc.) The guidance levels neither take in to consideration discomfort for people inside the building or structure nor vibration sensitive equipment inside the structure. The paper also presents the Swedish Standard SS 02521 “Vibration and shock - Blast induced airborne shock wave - Guidance levels for buildings”.

Jan 1, 2005

By Rundqvist

The best method to minimise disturbances from traffic to the neighbourhood and in Urban is probably to go underground. For obvious reasons this will cause vibrations, noise and other environmental effects which need very strict regulations and quality assurance in order to complete the work successfully. One project is “Southern Link”, a part of a ring road system. The system of tunnels includes 16 kilometres of tunnels right beneath the south part of the city of Stockholm. At least 20.000 people will be or could be affected by different kinds of disturbances and pollution such as vibrations, noise, gas and groundwater. Another project is the “Arlanda Link”. A new railway with three stations has been built under the existing and running to Arlanda airport with its terminals. Authorities have carefully judged these projects, which cause complaints from neighbours due to disturbances. The blasting operations are professionally managed by the contractors and controlled by consultants to keep the regulations according to the Swedish standards, which are well described in the tender documents by risk analysis and technical descriptions. In spite of that, one conclusion is that it is not always possible to go underground without exceeding stipulated regulations with existing technique. Some of the regulations also double the cost of excavation

Jan 1, 2001

By Noel Dent

The Electrodet@ Electronic Detonation System Wilere are we going with regard to Accurate, Reliable, Easy to Use and Cost Effective Initiation using electronic initiation techniques? Improvements and applications in theJierd

Jan 1, 1995

By Ed Clah, Catherine Aimone-Martin

The vibration response of a 30 in. diameter high-pressure (845 psi) natural gas pipeline to 11 coal mine blasts was measured. The X-52 steel pipeline was buried 7 ft. below the ground surface. Ground and pipeline motions in terms of velocities were recorded on the pipeline, in the ground adjacent to the pipeline, and near the ground surface directly above the pipeline. These data were used to estimate the maximum stresses and strains in the pipeline occurring during the blasts. Pipeline standoff distances varied from 264 ft. to 3720 ft. Two blast hole layouts and timing schemes were used. One represented highly confined blasts to limit movement of the shot overburden that generated high ground motions at the pipeline. The second represented patterns that provided greater relief and lower the ground velocities at the pipeline.

Jan 1, 2003

By John Brown

Let’s talk about things that you, the driIl boss, the pit boss and the driller can do to eliminate the trend in drilling related accidents that have come to plague our industry in recent years. My paper will focus on reaI issues, problems and solutions that will affect our everyday outlook and attitudes about our jobs and lives. There are some real hard facts we must address if we are going to reverse this terrible killing trend.

Jan 1, 2000

By Robert Hopler

In accordance with the 57th section of the Explosives Act, 1875, the following report on the working of the Act during the year ending December 31, 1903, is submitted. There have been no modifications of the law during the year. No complaint is made of any falling off in the general condition of factories and magazines, and in one instance only during the year have legal proceedings been taken for any irregularity. The occupiers of factories and magazines have invariably shown perfect readiness to remedy any defects, and the managers have themselves in many instances introduced improvements tending towards greater safety. The number of deaths (5) from accidents by fire or explosion in the manufacture of explosives is below the average for the decade (6•4). Looking to the large number of persons employed in this trade, the number of deaths is not excessive and will compare favorably with the death-rate in other dangerous trades. Notwithstanding the large increase in the manufacture of explosives, the average number of deaths has greatly decreased since the passing of the Explosives Act, whereas the number of fatal accidents with explosives under conditions to which the Act does not apply appears to increase with the extension of trade.

Jan 1, 2006

By Satish Kate

Indian limestone mines which are highly mechanized in operation and supply limestone to the cement plants have been quite successful in devising ways and means to optimize blasting parameters, so as to have best fragmentation, powder factor, and cost of excavation. In primary blasting mechanized or manually mixed ammonium nitrate Fuel Oil is quite popular in dry holes, and in case of watery holes conventional packaged slurry/emulsions are being used. In order to avail the low density characteristics of the ANFO, some limestone mines have also used Saw Dust and Rice Husk along with ANFO. A number of field trials have been undertaken to explore the suitability of mixing rice-husk and saw dust with ANFO. Presently, about 10% of rice husk/saw dust is being used only to expand the explosive column. The main technical consideration for the use of saw dust/rice husk, has been to reduce the final density and increase the occupancy of explosive in the blast-hole. This not only lowers the detonation pressure in the blast holes, but also reduces cost of explosive without compromising on the fragmentation quality. Besides, with sleeping of the charge there is no substantial fall in the blast quality.

Jan 1, 2006

By B Mohanty, G Ludwig

A thorough assessment of development drilling and blasting practice was carried out at two underground mines at INCO operations in Thompson, Manitoba. The study showed that significant improvement in productivity can be achieved through careful selection of explosives and loading practice, and modifications of the standard blast lay-out. The analysis involved assessment of the effectiveness of various perimeter blasting methods, employing selected explosives and loading practice in both jumbo and jack-leg rounds. The blasting pattern as well as burden and spacing were varied to determine their effect on the blast results. The various types of explosives used were, pneumatically loaded ANFO, with and without detonating cord tracing, extra-strength detonating cord, and slurry and emulsion explosives with and without cord tracing. The study also dealt with various means to achieve increased rate of advance in both jumbo and jack-leg rounds. The diagnostic measurements consisted of VOD, 'burn' marks or half-barrels on perimeter wall, and blasting vibrations. The effects of geology, firing sequence, blast lay-out, and drill hole deviation on the final results were also examined. The results of the study have been shown to have very important bearing on the design of development round blasting.

Jan 1, 1998

By Frank Sames

Ground vibration levels are generally predicted using equations such as the USBM equation implementing the scaled distance concept and describing geological and blast design parameters in a ground transmission constant.

Jan 1, 1995

By Brent Blanchard

Dallas/Fort Worth Airport recently took a major step in its fiveyear expansion project with the explosive demolition of the Hyatt Regency Hotel West. Built in 1965, the Hyatt Regency held the distinction of hosting five U.S. Presidents over the years and was reportedly one of the first hotels in the world to be built within an airport’s boundaries.

Jan 1, 2003

By John Yenter

"Unique blasting problems during reconstruction and expansion of 100 year old buildings toaccommodate gambling. Located on steep mountainous terrain and linked by narrowroadways, the towns of Central City and Black Hawk challenged blasters to exceptionalmeasures in order to control over_break, vibration, public exposure and damage to thecharacter of these historic mining towns. Utilities were also upgraded to fit demands of asmuch as 800% volume change in one year."

Jan 1, 1993

By David P. Reddick

Economics is a social science dealing with the allocation of scarce resources. In modern times the “science” was identified by Adam Smith in his book, The Wealth of Nations, written in 1776. Mr.Smith, highly influenced by the Mercantilists of the 17th and 18th centuries, identified the “Invisible Hand” which would lead every individual to pursue selfish rewards in purchasing goods. He speculated these selfish motives would result in the best good for all. Price would be determined by barter, at a point where self-centered customers and vendors were mutually satisfied. Today, Smith’s theory is known throughout the world as “Capitalism” but most often termed “Free Enterprise” in the United States.

Jan 1, 1992

By Billy J. Thorne

The damage model in PRONTO simulates the dynamic fracture behavior of brittle rock. It is based on work started by Kipp and Grady, [lg] continued by Taylor, Chcn and Kuszmaul [I91 [20] and recently.modified by B. J. Thorne (first documented here). The essential feature of this model is the treatment of the dynamic fracture process in rock as a continuous accrual of damage in tension, where the damage mechanism is attributed to microcracking in the rock medium. The fundamental assumption of the damage model is that the material is permeated by an array of randomly distributed microcracks which grow and interact with one another under tensile loading.

Jan 1, 1989

By Kwang-Tae Kim, Yong-Kun Choi, Jeong-Soo Chong, Yun-Jae Lee

An annex building at the former Agency for National Security Planning(NSP) complex located in downtown Seoul was demolished by progressive collapse method. This work was done as a part of efforts to restore the landscape of Namsan Mountain which lies in the Center of Seoul. The five-story reinforced concrete structure was razed in 5.5 seconds by the 29kg of high powered explosives which were placed in some 320 holes in the building with floor area of 2,577 m². The asbetos and all the other finishing materials in the building were removed before the demolition and the specially coated wrap minimized the spread of blasting dust. Seismic and air overpressure waves were monitored at 8 points, which were below safety limits and the continuous communication with neighborhood prevented any complaint.

Jan 1, 1998

By Bill Williamson, Doug Richmond, Kerri Kuntz, Gus Gilman, Larry Heywood

This was a description by the poet of what occurred over two centuries earlier to Hannibal’s troops as he passed through the Alps. Interestingly, the pass that many feel is the route that Hannibal chose, Col de la Traversette, is the sight of possibly the earliest avalanche mitigation known. Monastery records describe a tunnel built in 1470, near the top of the pass designed to protect pilgrims from the upper slopes. For the next several centuries, avoidance and reinforced structures were the primary tactics to defend from avalanches

Jan 1, 2009

By Stuart Brashear, Lee Schettler

The effect of water on several ANFO/emulsion blend ratios are documented by both physical observations and analytical testing to demonstrate the effect even small quantities of water can have on water resistant blends.

Jan 1, 1996

By Alan Jorgansen, Dave Hummer, Scott Scovira

Kennecott Energy's Colowyo Coal Mine is the largest open pit coal mine in Colorado and produces 5.5 MM tons per year. Colowyo uses the terrace mining method to recover up to seven seams of rolling coal ranging in thickness from 5 to 20 feet. Draglines are used to strip overburden ranging from 60 to 120 feet thick off two coal seams. These two seams are characterized by soft and fold fractured coal and in past practice cast blasting caused excessive coal damage. As a result, to ensure minimal coal damage and high coal recoveries, the overburden was excavated in two passes. The first pass removed the upper overburden to within 10 to 20 feet of the coal seam. The second pass removed the remaining overburden above the coal. Two-pass mining was effective in controlling coal damage, but also carried significant additional costs.

Jan 1, 2003

By Larry R. Fletcher

A misfire results when explosives fail to detonate as planned during a mine blast. Accidental detonation of misfires is a frequent cause of personal injury, equipment damage, and lost production. In an effort to minimize these problems, the Bureau of Mines investigated the causes of misfires, methods for detecting misfires, and procedures for their disposal. During this investigation, input was obtained from explosives suppliers, mining companies, blasting contractors, blasting consultants, and governmental agencies. Additional data were obtained through detailed analysis of blasting accidents involving misfires.

Jan 1, 1983

By Rob Farnfield, Yuill Gavin

The rock blasting industry continues to be under pressure to reduce the level of vibration induced by the use of explosives. In recent years much research and development has been directed to minimizing vibration levels by controlling the delay period between blast holes. The most commonly applied technique is known as Linear Superposition. This technique takes the vibration produced from a single-hole test shot and simulates the vibration that would be produced from a full-scale production blast. The simulation can be run with various delay periods and the optimum delay chosen. The success of the Linear Superposition technique depends to a great extent on having accurate delay detonators and on the single-hole test shot reliably indicating the vibration signal produced from each hole in a production blast. A quarry-based case study is given illustrating how these assumptions are not always valid. In this case the use of electronic detonators has controlled frequency but not vibration level. The paper goes on to describe a series of single-hole test shots in an U.K. limestone quarry. The vibration 2 signals recorded are examined in terms of variations in free-face provision, blast geometry, explosive properties, etc.

Jan 1, 2001

By Wenbo Lu

A combined method is present in this paper in analysis the dynamic stability of rock slope under the loading of blast induced seismic, in which, by combining the dynamic load calculating method of quasi-static method with the load inputting method of dynamic finite element method, such factors as the decay of seismic wave along its way of propagation, the frequency. amplitude. the phase difference of seismic wave, etc., can all be taken into account in analysis of the dynamic stability of slope.

Jan 1, 1999