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By B Mohanty, R Yang

Blasting vibration information is now commonly used to diagnose blast malfunctions. These range from limiting vibration levels to protect normal dwellings to determining scatter in detonator firing times, and even to rating of explosives in the borehole. Although blasting vibrations have the potential to yield reliable information in all these issues, there are key restrictions on their specific use, which are often ignored. These include all aspects of instrumentation, and sensor layout, as well as methods of analysis. This paper highlights these limitations. It emphasizes the distinction between near-field and far-field seismic recording in terms of borehole dimensions and blast geometry. Several case studies from both underground and open-pit blasting operations are discussed to illustrate and emphasize the essential characteristics of blasting vibrations and their optimal use in diagnosing blast malfunctions.

Jan 1, 1997

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 Bert Bahnson

As farms decrease and subdivisions increase there is a continuing demand for easy and safe silo removal. A few years ago I attended one of the Omni istribution explosive classes and was impressed by a product designed by Omni owner Bill Nixon called the Omni Breach. Its original purpose and main current use is law enforcement; specifically door breaching and tactical operations, with most of the force coming from water using a minimal amount of explosive component. I experimented with various charge strengths on concrete and found that it can be easily shattered with little flyrock or airblast. A neighbor of mine had an old silo within a foot of a barn that he was rebuilding and inquired about its removal. His property was sandwiched between an elementary school and Interstate 40, so I told him that I would do some test shots and if the results proved satisfactory, I would take the job for free to test the following theory.

Jan 1, 2006

By Earl C. Hutchison, Gene Smith

Extensive blasting was required to construct an underground tunnel for a 90 inch sewerage relief line. The tunnel and required excavation extended under an upper middle-class residential area in Atlanta, Georgia for more than a mile and a half and required the use of more than a half million pounds of explosives in the immediate vicinity of houses and residential apartments valued at more than 16 million dollars. Other houses and property valued at more than 80 million dollars were within range to claim blasting damages. An effective blasting damage control program was carried out which limited the number of blasting damage claims to less than 2-1/2% of the total number of potential claims. All but three of the small number of blasting damage claims which were made were effectively denied without any resulting legal actions and less than $3,800 was paid for settlement of the three claims.

Jan 1, 1981

By Joshua Hoffman, Catherine Johnson, Braden Lusk

The practice of dual initiation using precise timing from electronic detonators in boreholes is thought to be beneficial for increasing fragmentation at a desired location in the rock strata. This increased capacity for fragmentation is understood to be a product of both the collision of detonation waves in the explosive column and an increased energy liberation rate, each resulting from dual initiation. In addition, the collision of shock waves from two adjacent blast holes is suggested to improve fragmentation at the location the two shock waves meet, which can be controlled with precise timing. This paper presents the results from scaled laboratory experiments where converging detonation waves and shock waves were studied.

Jan 1, 2014

By P Bellairs

The Hamersley Province is located 1OOOkm to the North of Perth .the Capital City of Western Australia and is of major economic significance due to the mining of extensive deposits of Haematitic Iron Ore for both domestic and export use. A small but significant proportion of the waste associated with these deposits presents problems due to its ability to spontaneously combust and react with explosives resulting in premature detonations.

Jan 1, 1996

By R Holmberg, C Sjoberg, B Larsson

This paper describes the excavation of an underground naphta storage facility at Stenungsund in Sweden. The main purpose with this paper is to give an overall view of how the excavation was carried out and in what type of bedrock the storage was built. Emphasis has been done to highlight the importance of using cautious blasting to avoid blast damage in the remaining rock. Attempts has also been done in order to evaluate what the degree of Swedish cautious blasting has meant for the rock support costs during the construction period.

Jan 1, 1984

By D Vrkljan, Z Ester

There was no use of emulsion explosive at Croatia till 1997. Several attempts have been done to bear out the economical and technological affordability of applying the emulsion explosive for open pits and to make the contractor familiar with characteristics of emulsion explosive exepiting experimental blasts series at more open pits on different kinds of rocks. Testing the efficiencies of emulsion explosive there has been applied the original method for linear enlargement of burden of Sc.D. Josip Krsnik’s from Mining, Geology & Oil Faculty, University at Zagreb. The method of linear burden’s enlargement, in distinction from other methods concerning these problems, has been carried out in situ, under real exploitation conditions whereas the physical-mechanical rock’s features, geological conditions, bed relations and rocks’ structure influence the blast efficiencies. On such way, by mean of method the precise boring and blast sizes will be reached for each kind of rock and geological structural bed’s conditions referring to specific explosive type. The technical-economical analysis indicates the most favorable explosive type for specific bed.

Jan 1, 1999

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 Alastair Torrance

The performance of commercial explosives is clearly influenced by the conditions under which they are used. Mining companies are supplied with Technical Data Sheets which provide details about explosive properties and its suitable application. These are generally produced using laboratory techniques which may not accurately reflect the quality and performance of the product in the field.

Jan 1, 2013

By Salah A. Taqieddin

Blast casting or trajectory blasting, as it is sometimes called, is an innovative mining technique that has been receiving increasing acceptance among operations of surface coal mines and quarries as a means of offsetting the rising cost of mechanical excavation of overburden with a high overburden-to-ore ratio. Many similarities exist between geological characteristics of overburden formations of phosphate beds and the formations that conceal coal seams. Both are sedimentary origin and are removed for mining in an identical manner (i.e. use of a dragline or shovel to strip or cast the overburden aside).

Jan 1, 1997

By Gimtong Teowee

SDI has launched the Electronic Detonator Blasting System containing a set of robust serial protocol and hardware exhibiting great ease in field usability and deployment. Programmable delay time with increments of 1 ms up to 10s is possible with excellent timing accuracy. Bus length of up to 2 km containing 1600 EIMs can be employed. A key feature of the SDI Electronic Blasting System has been its high tolerance towards current leakage in the bus line.

Jan 1, 2007

By Robert Hopler

In part one we discussed a Chinese seismoscope allegedly invented and used in the year 136 (or 132, depending on the source). Interestingly, historical references to the measurement of earth movements then seem to be nonexistent until up into the 1700’s. There could be two explanations for this hiatus: first, that there were no earthquakes in the world for 1600 years, or, second, the “Dark Ages” really did exist, where intellectual inquiry and all sorts of learning came to a halt. Of course there were earthquakes, so the explanation for the lack of a record of invention is the reality of the Dark Ages. explained is the fact that the Dark Ages ended in about A.D. 1000, but that is beyond the scope of this story.

Jan 1, 2006

By Bryan J. Lane, Paul N. Worsey

The recommended maximum explosive weight for boulder blasting using internal charges is 0.1 O-kg/m” (3.5 oz./yd) (Olofsson, 1988). Normally this charge results in excessive scattering and flyrock, creating increased liability for the operator, especially in congested areas. An alternative technique using smaller explosive charges is being developed at the University of Missouri - Rolla. It is designed to reduce boulder scatter, flyrock and fumes and allows shooting in close proximity, using common blasting products.

Jan 1, 1999

By Mark S. Stagg, Stephen A. Rholl

The firing times of millisecond-delayed initiators are random variables that exhibit varying degrees of scatter. This scatter can cause crowding and overlap of adjacent delay periods, which results in adverse effects on safety, fragmentation, and blasting vibrations.

Jan 1, 1988

By T Weaver, R Dick, R Sivakumar, C T. Aimone

A series of small-scale crater tests were performed in concrete and sand in an effort to understand the cratering process in large-scale field blasts. The surface orientation of these tests varied from flat to a 30° slope. In comparison to previous crater experiments in competent oil shale, the crater tests in concrete produced craters similar to those in oil shale after scaling the measurements for differences in the mass of explosives among the experiments. Material strengths and the degree of brittleness had a significant effect on the size and shape of the crater. The small-scale sand tests resulted in some crater features that were similar to large explosive tests in alluvium and soil.

Jan 1, 1986

By Claude Cunningham

Blasthole pressure is the starting point for many blast design calculations, but the way in which it is usually derived, from measured detonation velocity, indicates that more thought is needed as to its true meaning and implication. The general impression is given that the energy in the hole is defined by VoD, but rarely is this the case. VoD is defined by the energy released in the Detonation Driving Zone between the shock front and the Sonic (or 'CJ') surface, and for commercial explosives it is normal for reaction not to be complete within this zone. Reaction and energy delivery continues behind it, not reflected by VoD. Thus it would be more appropriate to use the theoretical VoD, not the measured VoD, to derive the starting pressure, since this would reflect the energy input of full reaction. In decoupled situations, the derivation of pressure at the blasthole wall using a polynomial decay concept is also of debatable value, and an alternative is offered.

Jan 1, 2006

By Larry R. Fletcher

The Bureau of Mines obtained blasting accident data from the Mine Safety ant Health Administration (MSHA), U. S. Department of Labor. These data were analyzed to determine the most frequent causes of accidents in mine blasting. Accident totals for 1971 through 1981 are tabulated for metal-nonmetal and coal mines both surface and underground. In the past 11 years (1971-1981, inclusive) there has been an annual average of 9 fatal and 121 nonfatal blasting accident victims. Underground mining averaged 6 fatal and 93 nonfatal injuries each year.

Jan 1, 1983

By B de Raadt

After discussing mechanisms of collapse for the explosive demolition of towers in general and cooling towers in particular, author comments upon a blasting operation in which four cooling towers were involved. The intention of this paper is to present reliable parameters, generally valid for the explosive demolition of reinforced concrete cooling towers.

Jan 1, 1978

By William A. Travnik

For more than 60 years, ESSO RESOURCES CANADA LIMITED has been producing and refining oil at a small refinery in Norman Wells, Northwest Territories, and supplying diesel fuel and other oil products to northern markets. In 1982,ESSOwas granted governmental approval to expend production from the oil field from 475 cubic metres a day to 4400 cubic metres a day. This $800,000,000projectproceeded ahead of schedule for a start up in 1985.

Jan 1, 1986