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By Jikai Rong Changai Liu

The dig instrument by blasting is a,new product we developed(See Fig. 1) It is an apparatus to dig hole at the ground. It is composed of combustor A, combustor B, charge pipe and shock head. Work characteristics of Combustor A are that combustion time is 1. 5 seconds, driving force is 725kg. Work characteristics of combustor B are that the combustion time is 1. 3 seconds, driving force is 460kg. After the combustor is ignited, the charge pipe is drived into ground immediately. Then, whole dig instrument is threw out automatically, but explosive in charge pipe is left in ground and blast in the twinkling. The diameter of vertical hole formed by blasting is 3cm to 60cm which is controlled according to engineering requirement. The maximum depth of the hole diged by using the dig instrument is 2M. It applies to blindage of single solidier in military affairs, and hole planting pole as well as sewer in civil use and so on. The two shots are charged in combustors to dig a hole. The maximum weight of shot is 490g, minimum is 130g. The whole process diging hole is completed automatically in about ten seconds.

Jan 1, 1998

By P D. Katsabanis

The phenomenon of sympathetic detonations in blastholes is investigated by comparing experimental observations and numerical modelling results. Numerical modelling using the TDL computer code and Forest Fire decomposition rates for commercial explosives has shown the importance of blasthole diameter, impedance of stemming material and host rock. Comparison with experimental observations has also shown that sympathetic detonations cannot always be treated as shock to detonation transitions (SDT). Examination of previous results which have been obtained from calibrated low amplitude shock experiments reveal that there is an ignition threshold prior to the detonation threshold. The difference between the two thresholds is more pronounced in the case of air bubble sensitized products. The ignition threshold can be very important under the confinement provided by the blasthole and the conditions of application. It also correlates well with the pressures expected at the gap distances of interest in the practical application. It is suggested that critical energies are used as the criterion for cross initiation in blastholes. Practical suggestions based on the numerical calculations and experiments based on these calculations are also given and discussed.

Jan 1, 1992

By Michael S. Wieland

This report discusses measurement techniques utilized in and trend results obtained from research on delay blasting malfunctions in underground coal shots at the U.S. Bureau of Mines. Charge malfunctions occur during delay blasting in underground or surface mines, rendering the explosive operations more hazardous and less productive. Modern instrumentation techniques reveal several types of reduced charge performance, resulting from cross-hole interactions. Two receptor (wave-target) charge malfunctions were detected in fourteen shots that were undeniable. There were other receptor charges that exhibited under-performance by registering out-of-tolerance or noticeably reduced detonation rates. Delay blasting generates tremendous shock waves and rifting forces that fracture and heave the surrounding stratum and unfortunately damage remaining unfired charges. This report contains two graphs, representing roughly 1% of total records, that show donor (wave-source) charge shock waves and rift (reaction-to-heave) compressions. These debilitating wave impacts precipitate modes of reduced charge performance ranging from weak detonations or misfires to sympathetic detonations. As recognized from previous research, impaired charges react poorly, perform less useful work, and yield fumes with atypical higher toxicity.

Jan 1, 1995

By Dale S. Preece, Steven Knudsen

A discrete element computer program, DMC (Distinct Motion Code) was developed to simulate blast-induced rock motion. To simplify the complex task of entering material and explosive design parameters as well as bench configuration, a full-featured graphical interface has been developed. DMC is currently executed on both Sun SPARCstation 2 and Sun SPARCstation 10 platforms and routinely used to model bench and crater blasting problems.

Jan 1, 1994

By D E. Shaw, J B. Case, J Gusek

Explosive casting of overburden is defined as the use of explosives in blasting to move overburden to a spoil pile without rehandling. Studies of the economic feasibility of the method, and the formulation of a design hypothesis involving rock properties, and blasthole geometry are presented. These studies indicate that if technical feasibility can be demonstrated to increase surface coal production, considerable economic advantage would accrue to coal mine operators.

Jan 1, 1980

By P Bellairs

The Hamersley Province is located 1OOOkm to the North of Perth .the Capital City of Western Australia and is of major economic significance due to the mining of extensive deposits of Haematitic Iron Ore for both domestic and export use. A small but significant proportion of the waste associated with these deposits presents problems due to its ability to spontaneously combust and react with explosives resulting in premature detonations.

Jan 1, 1996

By Salah A. Taqieddin

The blast casting technique of removing overburden is an innovative technique which was successfully used in the mining of certain surface coal and quarries. This method was found to be efficient in minimizing the labor and equipment cost while accelerating mining operation with safety. This method was successfully applied to horizontal as well as to dipping coal seams. Also it was practically applied to single as well as to multiple ore bodies

Jan 1, 1992

By J P. Tidman

The problem of blasting fragmentation has received a good deal of attention in recent years. Progress by the scientific method requires a good set of experimental data as a benchmark to test models. Recent models have become so complex that it is not possible to use the results of field data because the complete set of parameters needed to describe the rock and/or explosive are not available.

Jan 1, 1991

By Alan Minchinton, Ian Kirby, Jim Chan

It has long been known that successful blasting in soft and hard rock can require the use of different explosives. While choosing an explosive of the right energy density is important, the dynamics associated with non-ideal detonation behaviour play an equally major role. Tuning the energy release rate of an explosive to optimise its blast efficiency can be likened to tuning an internal combustion engine to improve its performance.

Jan 1, 2014

By John C. Didlinger

How do you measure the highwall? Why do you even need to know the highwall measurement? Why is it important? The importance of this measurement is to help keep a level floor and to help control vibration. Nevertheless, since most of us are not mountain climbers, there must be a safe and easy way to make an accurate highwall measurement. So with these factors in mind, how do you make your measurement?

Jan 1, 1997

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 Fred C. Drury

The Explosives Engineer's concern for personnel training in the safe, efficient and effective use of explosives materials has grown in recent years. Available training options have also grown. Today's options include off-site training seminars and in-house training departments, both of which represent significant cost to the smaller producer.

Jan 1, 1981

By Thierry Bernard, Pierre M. Vuillaume, Michel Kiszlo

In the context of its studies for the french ministry of the environment and for the French national coal board, INERIS (the French institute for the industrial environment and hazards, formerly CERCHAR) has made a complete critical survey of the methods generally used to reduce the levels of blasting vibrations.

Jan 1, 1996

By Thomas H. Kleine, Alan R. Cameron, William W. Forsyth

In general the software required by a blast designer includes tools that graphically present blast designs (surface & underground), can analyze a design or predict its result, and can assess blasting results. As computers develop and computer literacy continues to rise the development of and use of such tools will spread.

Jan 1, 1995

By John Turner, James Lamb

The Minnesota Department of Transportation (MNDOT) has an extensive project to improve driving conditions and reduce hazards to motorists on US Highway 61 between Duluth, MN, and Canada along the north shore of Lake Superior. In 1991, the Lafayette Bluff Tunnel was completed just north of Two Harbors, MN, through a joint venture of Johnson Brothers Corporation of Litchfield, MN, and Obayashi Corporation of San Francisco, CA.

Jan 1, 1994

By Bert Bahnson

As farms decrease and subdivisions increase there is a continuing demand for easy and safe silo removal. A few years ago I attended one of the Omni istribution explosive classes and was impressed by a product designed by Omni owner Bill Nixon called the Omni Breach. Its original purpose and main current use is law enforcement; specifically door breaching and tactical operations, with most of the force coming from water using a minimal amount of explosive component. I experimented with various charge strengths on concrete and found that it can be easily shattered with little flyrock or airblast. A neighbor of mine had an old silo within a foot of a barn that he was rebuilding and inquired about its removal. His property was sandwiched between an elementary school and Interstate 40, so I told him that I would do some test shots and if the results proved satisfactory, I would take the job for free to test the following theory.

Jan 1, 2006

By Jason Baird, Philip Mulligan, Caleb Baumgart

This report details the pressure variances, measured at four pressure sensors placed equidistant from the center of an airburst explosion, as the blast pressure from a single charge expands radially. Many of the empirically derived equations used for predicting the blast pressures of an explosion, assume a point source detonation and that the radial pressure expansion is equal. The authors understand that the equations used to approximate the blast pressure may not have 100 percent agreement with the observed pressure. However, during previous research at Missouri University of Science and Technology (Missouri S&T) the pressure variances had a range of 1,200 psi, between the four pressure sensors placed two feet from the center of a 1/2-pound (226.8 gram) of hand packed C4. The variances indicated that at the close distance from a suspended explosive charge the pressure does not behave as that observed from a point source.

Jan 1, 2014

By John R. Schuring, Walter Konon

The 2.0 in./sec. peak particle velocity criterion traditionally used to protect structures from blast induced vibration damage is non-conservative for landmark structures. Various factors which must be considered in establishing vibration criteria for landmark structures are discussed. Existing criteria by past investigators for this class of structure are presented.

Jan 1, 1984

By Kevin Cole, Dennis A. Clark, F William Laslow

Since 1976, the Metropolitan Sanitary District of Greater Chicago, (MSDGC), has commissioned the excavation of a tunnel system in the Chicago area, hundreds of feet below the surface in solid limestone. This paper outlines the blasting patterns, explosive selections, and monitoring techniques used to assure a satisfactory job completion, following the specifications.

Jan 1, 1982

By R E. Otterness, M S. Stagg

The U. S. Bureau of Mines conducted 22 full-scale blasts to determine the effects of delay and explosive type on fragmentation. The shots were conducted over a period of 7 years in three limestone quarries and one granite quarry. Hole diameters, bench heights, and number of holes varied from 6.4- to 14-cm, 6.7- to 14-m, and 4- to 24-holes, respectively. Explosive performance and actual firing times were measured and screening was used to assess the fragmentation.

Jan 1, 1995