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By Stanley J. Vitton

An important factor to consider during blast damage investigations is whether the structure was constructed on collapsible soils. Traditionally, these soils have been considered to be soils such as loess deposits, which occur along the Mississippi River in locations such as Vicksburg, MS. However, recent research into collapsible soils has indicated that a number of soils may also fall into this category. A collapsible soil is any soil that is susceptible to large decreases in bulk volume upon saturation.

Jan 1, 1997

By Ralph King

Blasting has been completed when the lawyer calls to say that a landowner has filed a suit alleging damages to the roof of his home. Mitigation talks fail to produce an adequate resolution and the case goes to court. The blaster has pictures of the area made after the blasting was done showing the good condition of the roof. However the judge fails to allow the photographs to be entered as evidence and the homeowner wins the case.

Jan 1, 2008

By Jerry Bennett

A recant Bureau of Mines analysis has shown that failure of blast area security systems is the mayor cause of mine blasting accidents. Accidents occur during scheduled blasting because of failure to clear the blast zone, inadequate guarding, and failure of personnel to follow instructions, retreat to a safe location and/or take adequate cover. The high incidence of blastslte security-related accidents could be considerably reduced by increased attention to improving minesite blast-guarding practices.

Jan 1, 1984

By Gerald R. Coonan

Early in the open session of the 1979 SEE Fifth Conference panel discussion, someone asked a question of the panel concerning the future intent of the Office of Surface Mining and the regulatory limits established for ground vibration and air blast. The "gist" of the question was: "What assurances do we have that OSM will not promulgate a limit of 0.5 inch per second ground vibration, or some other number within the next two years or so."

Jan 1, 1979

By K Ramachandra Rao

This paper explains the methodology for assessing the efficiency of rockmass fragmentation by explosive blasting, from ground vibration frequency spectrum analysis of the blast event. Explosives are used in the mining, quarrying and construction industries for fragmenting rockmass to a suitable size. When an explosive charge is detonated, in addition to fragmenting the rockmass, it will also generate ground vibration and air vibrations. Efficiency of a blast depend upon percentage of blast energy wasted in generating ground vibrations and air vibrations.

Jan 1, 1994

By S B. Richardson, R E. Danell, D Mead, N T. Moxon

Explosives provide a very concentrated source of energy which is often well in excess of that required to adequately fragment the surrounding material. Blast design, environmental requirements, production requirements and the lack of detailed insitu geological data generally limits the degree to which the explosive energy distribution within the blasthole can be significantly altered using, for example, different explosive formulations or variable loading techniques. However, increased flexibility can often be exercised over a blast through the use of air-decks.

Jan 1, 1993

By M J. Ball, R Watt

ICI has developed a new electrical shotfiring system which has markedly improved safety features and operational advantages over existing initiating systems. The development of the 'Magnadet' Electric Detonator and the related product 'Magna' Primer were described in a paper presented at the 1981 S.E.E. Annual Conference. Since then the system has been adopted in many different applications and conditions around the world. The present paper describes these applications, the experience gained and the more recent developments which have taken place.

Jan 1, 1982

By C Hunter, K Fedak, J P. Todoeschuck

"Perimeter wall control has a direct effect on the overall grade of any underground miningoperation. Mine management at INCO's Birchtree Mine in Thompson, Manitoba requiresmaximum perimeter wall control to meet high safety standards and to maximize nickel orerecovery. If footwall or hanging wall contacts are damaged by over_blasting, the ore maybe greatly diluted, mine productivity may be reduced and safety problems can arise.Excessive or poorly distributed explosive energy is a major cause of damage to the hostwall rock."

Jan 1, 1993

By Jerome S. Brower

Quadrex-L is a two component liquid explosive which was developed by J. S. Brower & Associates, Inc. to facilitate handling and shipping, and use in unique applications, while emphasizing safety. It may be advantageously used for all explosive applications. Quadrex-L can be introduced into a preinstalled container configuration and may be easily drained or flushed from these containers when necessary to do so. This characteristic can be effectively utilized to reduce the hazard period during assembly or disassembly operations.

Jan 1, 1975

By David W. Zeeb

The use of an ordinary VHS video camera and a four-head player can be an effective tool to analyze surface blasting. The necessary equipment can be purchased for under $1,300 and will allow frame by frame or slow motion viewing of a blast in 33.33 millisecond increments. Rock breakage, movement, and timing can be studied in high quality slow motion. These studies can result in improved blasts by showing things that the eye can miss in real time.

Jan 1, 1992

By Callie Covert

This paper describes the application and results of a more efficient method of breaking boulders using dynamite and water. This method is being used for the disposal of boulders that result from pinnacle and cap rock remaining after blasting on highways and job sites. This method is a faster and less expensive use of dynamite to reduce oversized boulders than the conventional rock hammer. The problem with excessive fly rock has been substantially reduced when using this technique over traditional methods.

Jan 1, 2001

In this paper, the author points out the need to beware of simple time correlations as proof of cause and effect when comparing building cracks and blasting operations. There is a need to be aware of the many other causes besides blasting which affect buildings. Some of these have histories of cyclic behavior; others have a long-term increasing effect on aging and deterioration, often with poorly defined time histories. Many are so strongly site specific that generic relationships are difficult to quantify.

Jan 1, 1981

By James Keenan

Mesabi Range blasting has evolved in over a century of mining. The obstacles including: hard and heavily jointed rock, bitter winters and frequent wet holes; combine to create a unique challenge for blasters. This paper documents current pattern designs, powder selection and loading practices for these seven mines that consumes as much as 130 million lbs of explosives each year. Blasting is characterized by wide burdens and spacings, large diameter holes (up to 16-inch) and bulk loading of augered and pumped emulsion/prill products.

Jan 1, 1996

By J R. "Dick" Daniel

One of the more common tasks in blast management is the adjustment of: shot geometry, explosive energy, and shot timing parameters to achieve changes in blast outcomes and costs. Many of these shot parameters, once a delayed blast is initiated, are modified by the development of new free faces which change the original or static input values to dynamic values. These newly generated dynamic values are easily calculated and find use in fine tuning shot adjustments and in rationalizing blast outcomes in a systematic manner.

Jan 1, 1996

By Richard L. Ash

A question that frequently arises during litigation concerned with accidents or alleged damages involving blasting is "were the explosives used according to the best known standards"" The question is not confined to only law suits, however, but also everytime poor blasting results occur. Unfortunately, general guidelines that can be used to define what may be considered as proper practice have not been established by any responsible body upon which to base a reliable Judgment; more often than not decisions are made primarily according to personal opinion.

Jan 1, 1975

By C F. Argo

In the past several years the "Kelly Bar", an innovative device, which incorporates borehole d-rifling and explosives loading into a single detail, has come under scrutiny and criticism. The practical aspects of the Kelly Bar procedure is not questioned, and the system has been highly successful in expediting the loading of explosives in difficult and unstable formations. There have been a number of accidents indirectly associated with Kelly Bar loading and the point in question has become one of safety rather than mechanical feasibility.

Jan 1, 1975

By Craig Wilbour, John Stimberis, Rob Gibson, Lee Redden

Active avalanche control is the intentional triggering of avalanches while people are kept out of the hazard area. Explosives are frequently the most effective tool for triggering avalances. In a highway setting an avalanche control program will reduce total highway closure time, while providing greater safety to motorists and maintenance personnel. Avalanche control with explosives is effective when the snow is somewhat unstable and almost ready to slide naturally. Forecasting this condition involves having a network of local meteorological stations, examining snow structure, using mountain weather forecasts, doing snow strength tests, and having the results of ski and explosive tests. The method of delivery of explosives to an avalanche starting zone is governed by the accessibility of the starting zone. Common methods include; hand placing or throwing charges, remote delivery cableways, or "trams", surplus military weapons, and a compressed gas charge launcher, or "Avalauncher". Charges dropped from helicopters are also occasionally use. We have increased the effectiveness of our program by use of large elevated charges. Efforts are being made around the world to develop and utilize better methods for the safe, remote initiation, but procedures have varied dramatically between individual control programs. There is now a movement to review and standardize operational guidelines for avalanche control. Highway avalanche control is often done at night, during winter mountain storms. Heavy rain or snow, high winds, and high avalanche hazard, are common work site conditions. Commercial and economic pressures are increading, so methods that redice highway closure time are important. There are also many safety issues to be addressed in avalanche control work.

Jan 1, 2002

By Ashwani Jain, D K. Soni

Compressive strength of rocks is often required by mining engineers and quarrying authorities for blasting operations. Uniaxial compressive strength of rocks can be predicted with reasonable accuracy with the help of point load strength tests which can be easily conducted at site by the field staff, simultaneously as the cores are recovered from drilling operations. A number of diametral point load tests and uniaxial compressive strength tests have been conducted on the specimens of different rock types under air dried, and saturated condition as well to study the effect of ground water saturation on strength. It has been observed that due to saturation uniaxial compressive strength and point load strength get reduced to a maximum of 32 and 29 per cent respectively. It has also been observed that uniaxial strength is sixteen times the point load strength in air dried as well as saturated condition. However, this factor used for calculating uniaxial compressive strength may be reduced to a lower value for the safety of miners in field blasting operations.

Jan 1, 1994

By Katherine L. Heineken, Timothy J. Tope, Kim David Murphy

One method for small arms disposal is the use of a deactivation furnace or explosive waste incinerator. There are numerous hurdles a facility typically encounters to get the furnace or incinerator fully operational and permitted. For example, one Department of Defense installation was in the permitting process 7 years, which included numerous facility upgrades and modifications. This paper will discuss the technical approach for proactively addressing permitting issues and requirements and will identify potential pitfalls to avoid as well as ways to reduce costs. For example, when determining the waste profile, the facility should forecast its treatment needs (taking into account the net explosive weight limits of the furnace/incinerator) and then classify the wastes into "chemical families" based on the type and composition of the wastes. One waste from each family should then be selected for potential inclusion in the trial burn. Modeling the waste disposal can help to narrow down the number of wastes requiring characterization during a trial burn, as well as the number of analyses.

Jan 1, 1997

By Lon D. Santis

This paper reports on an evaluation of the safety characteristics of short lead, 5 centimeter (cm), Magnadet1 detonators. The Magnadet initiation system uses magnetic induction principles to transfer electric energy from the firing line to the detonator without a physical connection. This study was initiated because the Magnadet initiation system represents a new technology and the Bureau is interested in ensuring that no potential safety hazards are introduced into the nation's mining environment. The Magnadet system and its proper use are described along with a discussion of how it works. The potential hazards examined are: stray current from mine service power, lightning, DC current, static electricity, and radio frequency transmissions. Tip strength is also evaluated. Experiments were conducted to evaluate some hazards and theoretical methods were used to evaluate others. The results showed that the Magnadet short lead initiation system does not exhibit any unusual safety hazards. The new system is at least six times as resistant to common hazards as currently used electric initiation systems, so long as the insulation is intact.

Jan 1, 1992