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

Repelling charges are small explosive charges detonated to frighten and drive fish away from a blasting zone just prior to detonation of a major explosive charge. Use of repelling charges has been recommended by natural resource agencies to mitigate the effects of submerged explosives. Blasting companies have used this technique in a "good faith effort" to reduce potential damages to aquatic resources. It has been assumed that noise or pressure generated by the small charge will drive fish from the immediate area, thereby reducing impacts from the much larger and potentially more-damaging blast.

Jan 1, 1997

By R J. Roach, D Roy

After months of discussion on ways and means to improve productivity in the shaft sinking process, it was decided to look at those areas where, historically, methods have been stagnant for many years. These categories included drilling, hole diameter, drill patterns, explosive types, explosive loads, initiation techniques, cut design, wall control, fragmentation and heated magazines.

Jan 1, 1997

By B. M. P. Pingua & Md. Nabiullah

About 60 to 70 percent of bulk explosives are used in Indian coalmines to achieve coal production for power generation. Coal India Limited (CIL) is the major coal producing company in India. The average production of CIL is 400 to 450 million tonne coal per annum. The major subsidiaries of CIL are Northern Coalfields Ltd., Mahanadi Coalfields Ltd., Bharat Coking Coal Ltd., Eastern Coalfields Ltd, South Eastern Coalfields Ltd. and Western Coalfields Ltd. Most of the mines of CIL have watery holes. Therefore, high water resistance bulk explosives are preferred for better out puts.

Jan 1, 2008

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

"In order to increase control over blasting, it is important to identify the imperative mechanismsand to quantify their participation during the rock fracturing process. The useful energyreleased by the detonation of an explosive is split into shock and gas energies. The relativeimportance of these two energies in the rock fracturing process is still an area of active debate."

Jan 1, 1999

By Reynold N. Hoover, Davis S. Shatzer

The Bureau of Alcohol, Tobacco and Firearms (ATF) is responsible for the regulation and enforcement of the explosives laws codified in the Organized Crime Control Act of 1970, Title XI. To meet its responsibilities ATF has special agents, inspectors and specialists who regularly interact with the explosives industry. However, with just over 2,000 special agents and 800 inspectors and specialists, it is difficult to visit the almost 10,000 explosives licensees and permittees in the United States.

Jan 1, 1995

By R A. Farnfield

Measurement of the environmental impact of ground vibration from blasting operations is based almost exclusively on the peak vibration level generated. This measurement is known as the Peak Particle Velocity or PPV. The recorded PPV is used to assess the impact of the vibration both in terms of structural damage and human response. Limits for vibration are almost universally quoted in terms of PPV levels and, as a consequence, blast design for vibration control is centred around techniques for the control of this peak value.

Jan 1, 1996

By G Alan Foster

Because of the marked human response to blast effects and inherent defects present in many modern structures the real possibility of being named as a defendant in a law suit faces most blasters. Until recently even frivolous law suits involved a great deal of expense since legal costs were inevitably incurred whilst waiting for your day in court, which typically occurred some 2-4 years after the alleged damage took place.

Jan 1, 1989

By J Lyall Workman, Peter N. Calder

Operations using draglines to remove the overburden above coal seams have increasingly turned to cast blasting to improve productivity and reduce costs. Many such operations also employ active highwall pre- splitting to produce highwalls of well defined configuration, behind which the subsequent blast can be designed and implemented to maximize casting. In some cases isolating the block to be blasted allows water to drain out of the rock mass and provides the opportunity to use less costly explosives.

Jan 1, 1991

By H. C. Verakis

This paper summarizes blasting accident data for over a quarter of a century (1978-2004) for all types of surface and underground mining operations in the United States. Although many billions of pounds of explosives and blasting agent have been used by the mining industry, the accident safety record has improved significantly in the past 25 years. Over the past decade, approximately 5 billion pounds of explosives and blasting agents were used annually in the United States. Coal mining has been and continues to be the dominant user of blasting agents.

Jan 1, 2006

By Braden Lusk, Kyle Perry

Recent events and MSHA actions have resulted in discussion and reevaluation of the practice of sealing abandoned coal mine workings. In the past, MSHA has approved alternative seals based on a pass/fail system that required minimal engineering. Disasters involving fatalities led MSHA to impose higher seal pressure requirements based on research and experiments. Impending new MSHA seal regulations will force manufacturers and industry to obtain a high level of engineering expertise. The expertise necessary is in the field of blast resistant design, which is not easily accessible due to the limited number of experienced individuals within the mining industry.

Jan 1, 2008

By Thomas Bakley, Rob Lee, Jay Rodgers

The present state of technology in Controlled Blasting uses standard explosives’ products to create a crack between holes along a desired line of break. The resulting pre-split, post-shear or cut line is often of variable quality with unwanted damage at right angles to the desired cut line. A new concept in Detonating Cord manufacturing has provided a radically different performing explosive. This new Cord has reduced the Velocity of Detonation by more than a third. It changes the Detonation Pressure proMe of Detonating Cord to a lower and longer sustained pressure pulse. In addition, it develops more gas than conventional cords. At the same time it maintains all of the handling and reliability advantages of conventional Detonating Cord.

Jan 1, 2001

By S. Mandal, R. Singh

The demolition of structures with explosive though most rapid, safe and efficient requires planned blast design parameters with respect to geometric and strength properties of the structure to be demolished. The paper, here deals with successtil demolition of three old bridge piers by different blast designs. These piers were 11 m tall and very close to the existing bridge, The plan distance of the old piers from the existing bridge varied between 43 m and 14,25 m. The paper also deals with the mathematical concepts for the causes of such action of demolition/dismantling of structures.

Jan 1, 2001

By David E. Siskind

U.S. Bureau of Mines Report of Investigation 8507 was published in 1980. In a comprehensive analysis of all known blast damage studies plus new definitive data, the USBM authors adopted new safe level criteria of 0.5 & 0.75 in/sec for the frequency range corresponding to structure resonances. These were 3 to 4 times lower than the existing limit of 2 in/sec and are the most restrictive scientifically-based blasting criteria for the prevention of threshold hairline cracks in homes. The Bureau's own tests involved 76 homes in six states. In USBM RI 8507, those tests were combined with data from nine other studies from the US, Canada, Czechoslovakia and Sweden in an overall conservative summary analysis intended to preclude blasting damage.

Jan 1, 1998

By R W. Givens

This paper discusses emulsion performance and characteristics. Also presented are pattern design equations by a weight strength method, a "Q" factor method, and a coupled energy powder factor (CEPF) method. Pattern expansion by replacing ANFO with emulsion is presented along with quality control checks for emulsion products. The predicted performance of the calculated burden and the equivalent powder factor as a function of the emulsion percentage, as determined by the three methods, is compared. Field results indicate that of the three methods the weight strength is the moot conservative, the "Q" is overly optimistic, and the CEPF more accurately predicts the effect of coupling and is more consistent with a variety of emulsion and heavy ANFO products.

Jan 1, 1989

By Sam Oaks, David A. Smith

The new Corridor "G" Federal Highway Project in Logan County, West Virginia is the largest mass excavation highway project currently being built in the United States. Seven sections covering 14 miles of four lane highway and two connector roads will require over 30 million cubic yards of excavation. Construction is on a fast track schedule requiring the contractors to complete excavation and pavement placement in a little over 19 months. The two different general contractors have implemented several innovative Blasting and Excavation Programs to complete this project within the tight completion schedule. The paper expands on some of these unique programs that made the project a reality.

Jan 1, 1994

By Lyall Workman, P D. Katsabanis

Energy released by the explosive is typically partitioned in brisance, heave and losses. The fact that energy released in the P-V expansion curve below a certain point is lost has resulted in the concept of available energy. Through simple calculations it is shown that energy released at pressure levels thought to be low, amounts to a significant proportion of the total energy value. Furthermore, throw calculations indicate that the assumed loss of that part of energy does not justify practical results. Loss of energy at the low pressure levels may also not be justified from the fragmentation point of view as pressure levels below 1 kbar are enough to extend radial fractures around a borehole. Finally the equation used for the P-V behaviour of the explosive gases is important in throw calculations. Simplified approaches may not reproduce the performance of the explosive which is not characterized only by its energy content.

Jan 1, 1998

By Geoff Baldwin, Alastair C. Torrance

The use of monitors to assess equipment performance is carried out on a routine basis in many industries. The benefits gained through process control in knowing exactly how the equipment is working far outweigh the initial capital costs of the monitor. In the mining industry several dragline monitors have been developed and installed on equipment through out the world, but to date none has been fully accepted by the industry. This paper describes the use of a sophisticated monitoring system which incorporates an onboard processor to assess both dragline and blast performance. The use of a radio telemetry link for data transfer has removed the need for manual data collection and transfer, leading to a more efficient and powerful system. Significant effort has been put into the development and verification of a dig index to allow blast performance to be objectively assessed.

Jan 1, 1990

By G. R. Adhikari

A major part of mineral production comes from surface mining and there has been a rapid growth in this sector with the deployment of high capacity equipment. The importance of blast design combining appropriately both theoretical methods and practical approach has been well recognized in the field of surface mining. It is known that blast design has a direct consequence on productivity, safety and economic viability of these mines. Blasting is the most common method of breaking rocks in mining, but it has to be cost-effective. In coal production, for instance, drilling and blasting account for 25 percent of the total procution cost. In hard rock mining, the cost of drilling and blasting is about 40 percent. Due to ever increasing concern for cost-effectiveness together with environmental consciousness, designing blasts for each application has now become a stringent requirement and indeed a challenging task as well.

Jan 1, 2002

By Satish Kate

Mining of Iron Ore in India is done by Surface Mining methods and most of the deposits are massive and are occurring in Hills, surrounded by green forest cover. While majority of iron ore produced are from mechanized mining systems, some quantities are also produced from semimechanised mines. In mechanized mines, apart from state-of-the-art level of mechanization, the Run-off-Mine ore is subjected to multi-stage crushing, screening and washing/beneficiation, for improving the grade and ensure segregating of different size range. The steel plants within the country have been operating their own captive mines, where both lumps and fines are used in their furnaces. In case of mines, which exclusively supply ores to export market, the lumps produced yield very high price and thus efforts are being made to maximize lumps recovery. The mine, where the author had been associated, is an export-oriented mine which supplies iron-ore to Japanese steel plants.

Jan 1, 2004