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By Cameron McKenzie, John Heilig, Patrick Andrieux, Andree Drolet

It is widely accepted that both underground and surface blasting operations can de-stabilise excavations to the point where it can threaten the feasibility of mining through personnel safety or OK dilution. Research has been undertaken to outline a practical method in which the impact of blasting will be accounted for during the early excavation design stage by modelling, and during the following production stages by monitoring rock response to blasting operations.

Jan 1, 1994

By Charles A. Kliche

The Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) established a national program for responding to releases of hazardous substances into the environment. The funding mechanism for this program is the Hazardous Substance Response Trust Fund (commonly referred to as Superfund), which provides funding for the implementation of removal and remedial response actions.

Jan 1, 1997

By Norman Kramer, Roger Keller

The authors would like to thank Austin Powder Company for their technical support and input, specifically Stephen Harris, Jason Ryan, and John Capers of Austin Powder, without whose support this paper would not have been possible. Thanks are also extended to Nick Francis of Sandia National Laboratories and Jim Houseworth of Duke Engineering for their input regarding Performance Assessment.

Jan 1, 2000

The use of angled shot holes can be extremely effective in blasting faces that either have a great deal of toe burden or where it is difficult to give a drill access to a face due to backbreak and face erosion. However many quarry operators are wary of using angled holes because of the perceived possibility of increased flyrock and uncertainty of the driller's abilities to drill at the designed angle.

Jan 1, 1994

By Raymond V. Adolphson

The introduction of a new explosive component in 1955-56, called ANFO, featured much safer, effective blasting characteristics when compared to dynamite, accompanied by a notable reduction in cost. These savings mounted as borehole diameter or depth was increased with ANFO volume subsequently enlarged.

Jan 1, 1983

By Sushil Bhandari

Presented here is the simplified process of fragmentation of homogeneous rocks by blasting based on experimental studies. Small scale single hole blasting experiments on jointed limestone are described. Results show that directions of joints overshadow the degree of fragmentation and also influence the remaining rock. The possible influence of joints on the process of fragmentation of non-homogeneous rock by blasting is also discussed.

Jan 1, 1983

By R Ludeling, Klaus G. Hinzen, Ulrich Steiner, Friedrich Heinemeyer, Peter Roh

A method for hybrid modelling of blast vibrations in time domain is developed. Field seismograms of single shot experiments are combined with computer simulations. In this way firing times of blastholes in a pattern can be optimized due to diverse criteria like maximum velocity amplitude and frequency content of the vibrations.

Jan 1, 1987

By Carl Hendricks

AQUILA Mining Systems Ltd. is the world leader in drill monitoring, control and GPS based drill navigation systems for the mining industry. This paper will review the general design and application of AQUILA.s drill systems currently in use throughout the world and the key benefits that derive through their use.

Jan 1, 2002

By Mauro F. Dobran

The use of Slot Raises has been common for many years. The following presentation will compare various methods of developing these Slot Raises and introduce two new ones.

Jan 1, 1996

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 Valerie A. Rhodes, Catherine T. Aimone

Often blast damage litigation involves structural damage which clearly is not blast related. The fact that structures are observed to be damaged when blasting has taken place in the near vicinity of these structures does not necessarily mean that the damage was caused by blasting. If careful blasting and seismograph records were kept by the blaster which decisively indicate damage is not blast related, then other causes of structural damage need to be assessed. These include problematic soil characteristics and long-term changes in climate or subsurface soil moisture. This paper presents the evaluation process required to investigate soil problems leading to damage often attributed to blasting.

Jan 1, 1991

By Richard W. Watson, Julius Roth

The Bureau of Mines has recently completed a contract study of the hazards associated with surface mining.! Part of this effort involved an analysis of surface mining accidents associated with blasting activities. For this purpose, 71 reports of accidents investigated by the Bureau of Mines or the Mining Enforcement and Safety Administration (MESA), covering the period from 1962 to 1976, were collected and analyzed. In addition, blasting accident frequencies for the period 1973-1976 were extracted from the central computer files maintained by the Health and Safety Analysis Center (HSAC) in Denver, Colorado. This paper presents a preview of the findings, which are treated in more detail in the final report.

Jan 1, 1978

By Mark S. Stagg, Norman S. Smith, Rolfe E. Otterness, Stephen Rholl

Blast design parameters were studied in an attempt to quantify their relationship to rock fragmentation. The Bureau of Mines conducted a series of 29 reduced-scale shots at the University of Missouri-Rolla's experimental mine with bench size from 40 to 80 inches. Design parameters varied were burden, spacing, explosive diameter and stemming-explosive length. The shots had 3 or 4 blastholes fired at delays of 1-4 ms per foot of burden, based on previous tests that showed hole interaction could improve fragmentation by 12 to 20 percent over single-hole shots or simultaneous firing. All rock, 2000 to 23,000 pounds per shot, was screened and weighed to determine the fragmentation size-weight distribution.

Jan 1, 1991

By Kenichiro Yamamoto, Masaharu Murakami, Toshio Matsuzawa, Yoshiyuki Ikeda

In a series of tests, we examined the dynamic shock resistance of Emulsion Explosive in water and compared it with that of Dynamite and Slurry Explosives. Both the distance between donor and acceptor charges and the delay initiation timing of the acceptor charges were varied. The resistance to dynamic shock varied with the properties of the explosive. In the case of emulsion explosives, there seems to be a certain proportional relationship between the critical detonation distance and the delay initiation timing. Some blasting results with emulsion explosives are described.

Jan 1, 1983

By D T. Froedge

To preface these remarks, it is not intended that this paper be a criticism of anyone or any organization involved in drafting the current regulations, for it appears that everyone involved in the process has made an extreme effort to be safe. We wish to show that in this case by making huge safety margins, we have created an unsafe condition in another area. That is by creating vast safety margins in the area of mobile transmitter intensity versus distance scales we have caused a severe handicap in the use of the mobile transmitter in securing blasting areas. The use of these mobile transmitters, which are absolutely essential in clearing areas where there are woods, mountains, or urban structures is virtually eliminated because of the safety factors prescribed in the regulations. We wish to show that these mobile transmitter safety factors are much too great, and can be traded off to increase the margin of safety in the ability to clear blasting areas.

Jan 1, 1975

By Paul Worsey

A strong inverse relationship between rock face movement and stemming ejection is presented. Previously unpublished data from blast control plug research and development involving high speed video analysis, which was conducted between 1986 and 1988, is presented. Face and stemming ejection velocities were calculated for tests utilizing the same bench blasting configuration comprising; a 4 ft high bench in dolomite, 3 ft burden and single 1.75 in. holes loaded with 2 ft of small diameter cartridge emulsion. The singular difference between these tests was the stemming configuration. Varying lengths of stemming were used with the presence or absence of differing experimental configurations of blast control plug. The effectiveness of this plug has been published previously.

Jan 1, 1990

By Michael Swisdak, John Tatom, James Tancreto

In 2002, testing was proposed to generate needed data to assist in developing improved explosives safety standards within the US Department of Defense. This testing emphasizes two major areas: (1) full-scale donor/acceptor trials examining debris generation and acceptor response and (2) debris perforation testing of representative roof/wall materials. The full-scale donor/acceptor trials are referred to as the SciPan series. The first three tests in the SciPan series have been completed, as has the first phase of the SPIDER program. This paper describes the status and future of these testing programs, reasons for choosing specific tests, potential benefits, and planning for future phases.

Jan 1, 2006

By Paul Worsey, Gerald Rupert, Mark Kirkbride

The realignment of Highway H in the proximity of Crystal Cave (Springfield MO.) required the development of a blasting program that was both economical and efficient for construction, yet ecologically safe for the cave. Three component seismographs were strategically placed underground near prominent and sensitive cave features and the vibration levels from the construction blasting continuously monitored. Peak particle velocity (PPV) values were found to obey the square root scaling law and a peak particle velocity value of 0.3 in/sec was chosen as the safe maximum limit. This value proved adequate in preserving the integrity of the cave and its features. Scaled distances for the maximum and lower values enabled blasting personnel to select explosive charge weights per delay for given distance to the cave. Delays were determined from the dominant frequencies recorded underground.

Jan 1, 1997

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 Josephine Bones, Robb Larson, Daniel Miler

Avalanches are commonly mitigated through the use of explosives at ski resorts and above transportation corridors. Surprisingly, very little research has been conducted on snowpack response to explosive inputs, and efforts to model this response have been limited. The purpose of this ongoing research project is to ascertain an understanding of the dynamic snowpack response in relation to explosive size and height above the snowpack, coupled with snow conditions, to enhance avalanche control. A system of sensors and computer-controlled data acquisition components has been created to record the movement of snow resulting from the charge detonation. The system records acceleration vertically and radially within the snowpack at two distances from the point of detonation as well as blast air pressure at one location during explosive events. The data at two locations allows inferences to be made about the transmittance and attenuation of shock waves through the snowpack radially as well as vertically. The data shows that raising charges above the surface results in increased snowpack dynamic response when compared to surface detonations. Applying power function regression to accelerations for individual charge elevations, it was determined that both radial and vertical rates of attenuation were not dependant on charge elevation. Additionally, raising the charge also resulted in increased dynamic response at depth within the snowpack

Jan 1, 2012