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By J Lyall Workman, Peter N. Calder

Flyrock can be a serious hazard associated with blasting. Many surface blasting accidents involving injury result from excessive flyrock beyond the protected blast zone. Numerous cases of equipment damage at the mine, quarry or construction site have resulted from flyrock. Fragments propelled beyond the property limits of the operation have also caused injury and damage.

Jan 1, 1994

By Sri R. B Singh

Based on CMRI investigations in nearly 50 mines, the authors have developed two empirical formulae for the effective determination of burden and spacing in any kind of rock deposit. Along with charge loading parameters, decoupling effect and bench height, the equations consider rock characterisation parameter by incorporating 'RQD' i.e Rock Quality Designation. The value of 'RQD' may be obtained either by core recovery using diamond drilling or theoretically from the characteristics of joints or bedding planes. The derived equations may be used in any rock mass under varying geologic and charge loading conditions. The Formulae suggested herein, are explicit, simple in form and easily applicable in field purposes. The values obtained from the present equations are verified against various field data generated by CMRI during the past several years.

Jan 1, 1998

By David Harrison, Edward J. Walter, Meitra Ferek

A pre-blast survey can be a great tool in the prevention of blasting complaints and subsequent damage claims. In today's highly competitive industry, we are always looking for ways to become more cost effective. This paper investigates the importance of pre-blast surveys not just for regulatory compliance, but as an overall long term cost cutting and public relations tool.

Jan 1, 1995

By Dale Nies, David P. Childs

The open pit gold and silver mining operations in the State of Nevada have historically used simple row by row, echelon, or chevron delay patterns. Common practice has been to use detonating cord trunklines and either detonating cord downlines or nonelectric common in-hole delays in conjunction with surface delays. Several operations use a series of downhole nonelectric delays with an entire row loaded with the same delay to develop similar patterns.

Jan 1, 1991

By Thomas P. Dowling

With the increased usage of AN/FO type blasting agents and the introduction and development of non cap sensitive slurries, water gels and other types of blasting agents, proper initiation and boostering of these insensitive materials has become a most important aspect of every blasting operation.

Jan 1, 1981

By He Guangyi, Han Zhilong

This paper introduces the new technology of deep-hole blasting with water-soil mixed stemming to exposed stonework. Nine aspects of advantages are drawn in the paper based on tests of different types of charge and stemming under the conditions of different geology, height of bench and diameter of drill.

Jan 1, 1998

By D. K. Ingram, G. L. Mowrey, T. R. Rehak

This paper summarizes flyrock and blast area security fatalities from 1989 to 1999 and examines the causative factors. Coal and nonmetal mining used about 43 billion pounds of explosives and blasting agents between1989 to 1999. A majority of this consumption was used at surface mines. Accident data indicates that flyrock and lack of blast area security were the primary causes of blasting related injuries in surface mining. Fatal injuries due to lack of blast area security were attributed to: failure to clear blast area; failure to follow instructions; inadequate guarding; inadequate blasting shelter; and unsafe location.

Jan 1, 2002

By Paul Worsey, Gillian Worsey

The basic blasting class at Missouri S&T blast in the quarry at the experimental mine in preparation for the International Intercollegiate Mining (Mucking) Competition in April 2014.

Jan 1, 2015

By Philip H. Porter

Ammonium nitrate blasting agents continue to be the work-horse of the explosives industry. The versatile, low-cost, anfo products, whether packaged, poured, or bulk, continue to produce superior results for the explosive consumer who understands their limitations and capabilities.

Jan 1, 1984

By John W. Brown

For seventeen years, I have been involved in surface coal mining in the Mldwest coal fields only to find that once again, I have experienced a problem that was not known to exist in our area. The existence of high sulfur coal seams and pyrite-bearing formations coming In contact with ANFO mixtures has presented yet another potential problem facing the blaster.

Jan 1, 1992

By Daniel Moroz

This paper will provide an informative overview of the types of explosives and the various methods employed to control avalanches within the boundaries of major ski resorts.

Jan 1, 1991

By Randall M. Wheeler

Computer analyses of single hole signatures are often used to help blasting operators predict the type of ground vibration effects that may be produced from production blasts incorporating various delay intervals. Frequency analyses of single hole waveforms and subsequent multi-hole waveform simulations can allow an operator to determine the best type of delay intervals to use in order to minimize low frequency ground vibrations.

Jan 1, 1989

By J Mensah, G C. Sen

Often large boulders of rock have to be fragmented in civil or mining engineering operations. These oversize boulders are encountered after primary blasts in both surface and underground excavations of minerals. Various methods are employed to break large boulders into a manageable size for loading and crushing. These methods range from mechanical breaking (such as drop-ball and hydraulic impactor) to the use of explosives. Apart from these, static agents (such as expanding chemicals) are used in special circumstances.

Jan 1, 1989

By Monica Stuckert

Field studies were made at an Appalachia coal stripping operation to evaluate the differences in cost and performance between blast casting with pre-split dewatering versus conventional coal overburden blasting.

Jan 1, 1985

By Charles M. Curtin

A significant advance in nonelectric delay blast initiation has been achieved by Nonel shock tube, an invention patented by Nitro Nobel AB of Gyttorp, Sweden. Ensign Bickford has been licensed by Nitro Nobel to manufacture Nonel in the United States.

Jan 1, 1976

By D K. Joyce

Large diameter boreholes have become increasingly popular in underground mining. Drilling equipment can drill full rings, including vertical upholes. Special techniques are required to load upholes of three inch to eight inch diameter. The current methods for loading AN/FO and bulk or packaged emulsions are described.

Jan 1, 1988

By Christopher Smith

The critical nature of detonator function in blast design and its effects upon performance and safety of a blasting operation are well documented. Numerous laboratory and field studies have shown dynamic shock waves, generated by the detonating explosives in a shot, to be detrimental to the performance of the explosive columns in the adjacent boreholes. Laboratory tests conducted in Japan have explored the possible effects of dynamic precompression upon cartridges of emulsion explosives, which had been sensitized with different hotspot void producing methods. These tests uncovered significant differences in the magnitude of the dynamic shock wave pressures measured inside the different emulsion explosive cartridges, and demonstrated these pressure differences by crushing detonator shells inserted inside the emulsion cartridge. Basically, the results of these tests clearly showed the magnitude of the compressive force applied to the detonator inside the primed explosive cartridge to be a function of the mechanism that had been used to sensitize the emulsion (i.e., glass microspheres, plastic spheres, chemical gassing). The current study was designed to further explore the actual detonator failure mechanism in these dynamic precompression tests using live detonators inside the emulsion cartridge as opposed to empty detonator shells. The testing involved inserting commercial delay detonators inside emulsion charges, which had been sensitized with common hotspot void producing agents, and subjecting the primed explosive cartridge to the dynamic pressure wave generated by an underwater donor explosive charge. The effects of variations in the emulsion’s sensitization method upon the damage inflicted to the detonator were studied. Depending upon the degree of detonator damage, detonator crushing can lead to varying degrees of detonator malfunctions, ranging from sympathetic initiation of the detonator, to a reduction in delay time accuracy, to reduced detonator output, to complete detonator failure. Each of these malfunctions can have serious detrimental effects upon the performance and safety of a blasting operation.

Jan 1, 2006

By Jeff Wachendorf

As the title "Cast Blasting Around Town" implies, this paper details the starting of a cast blasting program in and around the town of Colstrip, Montana. As strip ratios have increased, the need to adapt and find solutions to provide coal at a reasonable cost to the captive power plants has risen. Colstrip, Montana has a long history of coal mining which dates back to the early 1920's when Foley Brothers began supplying coal strictly for powering locomotive engines. Early mining days starting in the 1920's and the progression up through the 1970's when mine mouth power plants were built will be discussed. To accomplish the desired results, early mining techniques included steam and electric powered equipment as well as a lot of actual horse power.

Jan 1, 2009

By Claude Cunningham

AEL’s Electronic Delay Detonators are in routine use and growing in both volume and breadth of application in Africa. This trend will continue and grow internationally owing to increasing pressure on rockbreaking operations to conform to sustainable development principles. A fundamental breakthrough has been achieved, bringing production blasting into line with technologies, which leverage performance through tight monitoring and control. When moving from pyrotechnic systems, benefits are normally realized without having to adopt different timing patterns, but significant additional benefits are realisable by using the flexibility and precision of the electronic units to enter windows of timing previously closed. The higher price and increased care needed are a worthwhile investment, enabling operations to cross the chasm to stronger revenues, but the system must be robust and suited to the application and personnel. Economic models are vital for keeping track of the potential and achieved benefits of these systems. Some resistance can be expected from those who stand to lose income as a result of the improved efficiencies.

Jan 1, 2004

By Douglas Anderson

In the early 1980s, a method for controlling blast vibrations other than by modifying the Scaled Distance came into use. Research studies had indicated that blast vibration could be simulated by detonating a signature hole with the vibration monitored at critical locations, and then using a computer to superpose the waveforms with varying delays. By choosing delay times that create destructive interference at frequencies that are favored by the local geology, the “ringing” vibration that excites structural elements in houses and annoys neighbors could be reduced.

Jan 1, 2008