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By John T. Day, Lex L. Udy, Mark L. Thomas

When we consider that the purpose of blasting is to fragment rock or ore so it can be subsequently handled and processed, we can see that the cost of blasting, in reality, affects all downstream steps of the mining (and in some cases) production processes. The productivity of all subsequent operations is influenced by the degree of fragmentation of the primary blast.

Jan 1, 1987

By Larry D. Lawrence, Gerald W. Greenway

Corrugated boxes have been the dominant shipping container for packaged commercial explosives for the past 3 decades. Recent changes in shipping regulations have dictated to the industry the adoption of enhanced standards dealing with the construction of fiberboard shipping containers for explosives. Effective October 1944, all shipping containers used for explosives will require individual certification verifying that the containers conform to the United Nations performance oriented packaging standards. The U.S. Department of Transportation will continue to enforce compliance to the new UN standards. A renewed emphasis on the design of corrugated shipping containers to insure industry compliance to the UN standards has been a joint development program between the explosive manufacturers, fiberboard container suppliers and the academic community. Along with drop strength, leakproofness, and vibration resistance, the individual stacking strength of corrugated shipping containers has come under tight scrutiny based on the new UN standards.

Jan 1, 1994

By S. P. Singh, Turgut Yalcin

The physical characteristics of blasted rock are fundamental variables affecting the economics of mining operations and are in fact the basis for evaluating the quality of a blast. A study was designed with the objective of quantifying the effect of muck size distribution on scooping operations in a mine.

Jan 1, 2002

By L D. Lawrence, R S. Day, Gordon Coleman

Commercial emulsion explosives are typically characterized by their relatively high detonation velocities due to the intimacy of oxidizer and fuel and to their sensitization with glass microballoons. However, numerous blasting operations in softer, more porous rock formations are better fragmented with slower shooting explosives. Although mixtures of emulsions with large amounts of ANFO (60-80%) can considerably reduce the high velocities, little water resistance is achieved with low levels of emulsion blended with ANFO. "Water proof" blends containing typically 50 percent of emulsion become quite costly due to escalating powder factors in ANFO patterns. Blends of sensitized emulsions with 20-30 percent ANFO retain the high velocity characteristics of the emulsions as well as increased densities which can also adversely affect blasting results in softer rock formations. The introduction of a reliable and predictable on-site gassing process for sensitization and density control of repumpable emulsions, with or without added ANFO, offers the end user the option of supplying a final product more suited to his blasting needs. The capability to widely vary final product loading densities and consequently product detonation rates better tailors the final explosive to different rock characteristics. The beneficial advantages of this system in softer rock formations have been well documented. Overall comparison between these variable density products with typical repump emulsions containing solid density control will be reviewed. Besides the obvious cost advantages and safety advantages of these systems the end user is provided more definitive control of his blasting operation.

Jan 1, 1990

By Paul V. Sterk, James Wieser

Mining in underground situations requires constant change due to changing ore bodies and economics. The Homestake Mine in its 122 years of existence has gone through numerous changes due to these factors. Recent sustained low prices in gold and ore bodies that are smaller or within mined out areas have forced the mine to reevaluate how these ore blocks will be mined. This paper will describe the design, drilling, and blasting of a complex ore block using the blind raise uphole bulk mining method.

Jan 1, 1999

By Robert L. Brooks

Blasting liability problems are frequently compounded by a company's inability to effectively communicate with concerned property owners and the lack of adequate complaint documentation. Often, by the time the insurance carrier becomes involved in a blasting claim, the situation has deteriorated to the point that a solution agreeable to both parties is virtually impossible to reach. The insurance carrier, wishing to minimize their lose potential may decide to pay on a somewhat questionable blasting claim rather than be drawn into lengthy civil proceedings that would ultimately end up in front of a jury with little chance for a successful outcome.

Jan 1, 1992

By Dale Preece, Stephen Chung

The DMC-BLAST (Distinct Motion Code) has been developed for modeling bench blasting to one or two free faces such as choked blasting in surface gold operation and cast blasting in coal mining, respectively. This computer code has been used to assist the analysis of rock mass displacement after a blast was initiated in an orderly delay sequence. Applications of this feature can be found in the studies of dilution control in surface mining of gold as well as coal involving complex rock structures. Recently, DMC-BLAST has been modified to include a designated delay firing order coupled with variable rock strengths in the blasted media. This newly added feature allows the investigation of the effects of delay firing order on rock displacement in blasting a complex interbedded ore-waste structure. Examples of blasting a steeply dipping coal seams and bedded rock structure, especially in coal mining operations will be addressed and the comparison of efficiency in blasting in an up-dip as opposed to blasting in a down-dip direction will be discussed. Also covered in the paper is a new application of DMC-Blast to simulate a stope blasting underground. Simulations of blasting in a few selected types of timing/structure combinations will be presented in this paper.

Jan 1, 2000

By William Reisz

The explosives and blasting industry has a commendable safety and security record, especially over the last several decades. This is due in large part to our newer technologies, better training and education, engineering practices, corporate initiatives, our professional organizations, and whether we like to admit it or not - our regulatory agencies.

Jan 1, 2012

By Michael S. Wieland

Delay detonators that are damaged by cross-hole wave interactions degrade blasting work and raise the risk of incidents. Damaged detonators impose risk, because they can retain sensitive explosives that respond to stray energy during recovery, inspection or disposal. Laboratory techniques were developed to rank the ruggedness of delay detonators under replicated field-shooting conditions. The hazards are tremendously magnified if trial detonators are installed directly in secondary explosives to rank initiation strength. Therefore indirect ranking techniques were sought that mitigate the risks without compromising the worthiness of the method. Four types of hardware fixtures, referred to as simulators, were developed to yield distinct forms of transient compression. The shock and rift versions generate compression pulses representative of in situ waveform components. The waiting time, until the trial detonator functions, duplicates typical delay periods. The trial detonator is mounted within water, which has a density and inertial resistance comparable to most blasting explosives. The work output from the trial detonator explosion is registered as fixture wall-expansion. This work output determines malfunction results, regardless of which type of simulator is used.

Jan 1, 1997

By Duane A. Houkom

Explosive demolition of concrete has been accepted as a safe and economical means of concrete removal for many years. I imagine that the early concrete blasters were experienced rock blasters who applied their knowledge to just another formation. Since a concrete foundation is generally located in a congested area, the owner is willing to accept the higher costs of mechanical removal,rather than promote "a new idea" to his management. This attitude is rapidly changing,making it possible to use the advantages of explosives in more congested locations.

Jan 1, 1982

By Lawrence Cheng-Kwang Hu

"Since the only available delay detonator in Taiwan is electric delay detonator, which can beaccidentally initiated by fire, i impact force, friction, static electric, lighting, radiotransmitter, and stray current etc., that always represent fatal threatens to the blasting crew.Fire, impact, friction can be Prevented by handling carefully; lighting also can be detectedwith proper instruments. But when a blaster find an unknown extraneous current in his welllaid down blasting cable; what a horror scence will be expected especially the electricdetonators have been connected already."

Jan 1, 1993

By Walt Meglasson

"Developing technologies in demolition equipment and processes have produced a newsophistication within the demolition industry. Yet, with increasing frequency, owners,architects, engineers, and contractors reject out of hand one of the safest and most effectivetools in the demolition industry today, specifically the use of explosives and blastingtechniques in man_made structure removal. The use of explosives in any application mustbe considered as a tool, no more or less dangerous than any other type of tool, when usedproperly. Accordingly, importance must be attached to recognizing the skill, integrity, andcare of those who use it. Massive amounts of information and help are available to assistthe rock blaster, ranging from the practical to the highly theoretical, but very littleinformation exists to guide anyone considering unleashing the power of explosives instructural demolition blasting. The planning and work required to execute such projects iscomplex, and the recognition of the different applications explosives can be applied to isthe first step."

Jan 1, 1993

By Thomas M. Keevin, Gregory L. Hempen

Natural resource agencies, under various regulatory authorities, are challenged with permitting underwater explosive use while at the same time protecting aquatic resources. Deciding on whether or not to allow use of explosives requires striking a balance between development and aquatic resource protection. A company's goal in underwater explosive use is to select methods that are both expedient and cost effective. Use of explosives is often the best alternative for engineering reasons or economic considerations. Over and above legal requirements, indiscriminate destruction of fish and other aquatic resources is not in a company's best interests because of concerns relating to public image, as well as the need to secure future contracts.

Jan 1, 1995

By Stephen A. Rholl

Computer software has been developed which uses fast Fourier Transform (FFT) techniques to analyze the frequency spectrum associated with peaks in ground vibration time histories. The procedure consists of filtering the FFT of a time history into individual frequency components.

Jan 1, 1996

By Brett Pielstick, E Emery Gray

"Construction of the new Acosta Bridge in downtown Jacksonville, FL required the removalof an historical center lift span bridge once one_half of the new bridge had been opened totraffic. This paper discusses the potential problems faced with the demolition phase of the projectas observed by the CEI (Construction Engineering Inspection) and the blasting consultants"

Jan 1, 1993

By Cathy McGinley, John Mullay, Clark Stancavage

The use of crater studies to evaluate explosive performance is a well-established practice in the Blasting Industry. Normally, this work utilizes larger charge sizes (>75mm) in order to minimize the influence of geological factors adjacent to the borehole. This can impose unwanted restrictions in the experimental factors accessible to investigation. Thus, for example, systematic studies of non-ideal performance in a somewhat practical setting is rendered quite difficult.

Jan 1, 1995

By Wang Xuguang Shen Yingfeng

Structure is the main aspect affecting the performance of emulsion explosive. Calculation of such structure parameters as osmosis pressure, interface area per unit volume etc. must be helpful to the understanding of the structure of emulsion explosive. This paper has solved the Laplace-Young Equation for simplified monodisperse emulsion system by Galerkin method, and gained the relationship between mean curvature, contact angle, volume fraction, fractional film area and interface area per unit volume. The paper also presents a new expression of osmosis pressure at non zero contact angle.

Jan 1, 1998

By Baron Fidler, Dave Lilly, Matt Budin

Cumulative sum (CUSUM) statistical process control methods have been used in many industries to monitor quality control results. CUSUM charts are a method to determine when small changes in data indicate a major change in results. E.S. Page at AT&T developed the method in 1954. In many blasting situations, vibration and air blast readings vary slightly from blast to blast. Whether the change is significant or not can be hard to interpret from the raw data. CUSUM charts can assist in determining whether a major change is taking place and when the change began.

Jan 1, 2009

By R M. Bhatawdekar, A I. Theresraj, H S. Venkatesh

Wadi Limestone Quarry is one of the largest captive mines of Associated Cement Companies Ltd, India. The mine management wanted to extend the excavation as close to the plant as possible for maximum exploitation of the deposit. The National Institute of Rock Mechanics and the management of Wadi Limestone Quarry carried out comprehensive investigations to evolve a methodology to control vibration and flyrock within safe limits.

Jan 1, 1999

By Sheila Luchansky, F M. Babcock, Daniel M. Sanders

A cooperative effort between a blasting vibration consultant, a blasting contractor, and personnel from the City of Las Vegas has dramatically reduced complaints from residential areas near developmental blasting projects. The principal methods used involved the preparation of an informative video recording which presents various aspects of the blasting operations, the design of a distinctive flyer which is attached to residential doors, and pre-blast meetings for information dissemination.

Jan 1, 1993