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By E E. Cloete, R I. McCrindle

Permitted explosives were previously nitroglycerine based and cap sensitive. Due to safety, health and environmental requirements, water-containing explosives, such as watergels and emulsions, were used instead. However, in order for these explosives to perform at their designed level during blasting, a more powerful stimulus than is delivered by detonators on their own is required.

Jan 1, 1999

By J R. Phin

The properties of all available modern blasting initiation techniques are reviewed. Primadets are nonelectric initiators, the nonelectric features of the system eliminates concern of premature initiation from static or stray currents. The loading techniques are simple and a minimum of training is required. There is no limitation in the number of necessary sequences in which the Primadet need be connected for initiation. This flexibility improves vibration control,and often reduces costs due to increased fragmentation.

Jan 1, 1975

Prediction of fragmentation in Taconite Mining is an important aid to blasting engineers. A simple theory relates the intensity of radial fracture per unit length to distance from the borehole, from which a power law for mass fraction passing versus size is derived. For the lower end of the size distribution, the equation agrees well with several published examples of fragmentation from sieving of full scale blasts. Large size fragments arise from interaction of fractures from neighboring holes and pre-existing joints. Analysis of two assumptions regarding radial fracture interaction shows that complex fragmentation distributions can arise from the simple mechanisms proposed. Measured fragmentation falls between the two extremes calculated.

Jan 1, 1996

By Bill Bauet, John Anderson

There are always security concerns when explosives are transported and stored, and these concerns are intensified in peacekeeping operations where explosives could fall into the wrong hands. MREL Specialty Explosive Products Limited has developed FIXORTM, a new approach to neutralizing landmines and unexploded ordnance (UXO). The product consists of two precursors: a flammable liquid in one plastic container and a totally inert powder in another; neither of these precursors is classified as explosives. Both precursors are approved for transport by land, sea and commercial passenger airfreight. The precursors are mixed to form an explosive immediately prior to placement next to the UXO or landmine. Initiation is by blasting cap or detonating cord.

Jan 1, 2001

By GF Brent, Armstrong L. W

It is recognised that presplitting is a special case in blasting which requires the reduction of conventional explosive pressures in order to avoid excessive rock damage. Two routes to achieving this are the use of reduced density explosives or the practice of decoupling the explosive from the blasthole walls. Applications of two such systems in large diameter, deep blastholes are described. Both systems were tested in presplits alongside sections charged with decks of conventional explosives.

Jan 1, 1998

A case history is presented where a variance was permitted by the court to change a 500 foot limit to 250 feet for blasting overburden at a surface coal mine in the proximity of a historic structure.

Jan 1, 1991

By Anders Lagerkvist, Agne Rustan, Tommy Edeskar

Landfills containing house hold waste produces methane gas during its decomposition. This gas can be recovered and used for heating purposes or as fuel for vehicles. Gas drainage pipes are installed in the landfill and connected to a central suction point. Methane gas is produced over several years until the slots in the drainage pipes are clogged by black mud. And the bottom of the vertical drainage pipe are filled with mud and water. The hypothesis tested in this paper is if blasting in the drainage pipes could activate the production and flow of methane. In the first part of the paper we have studied what maximum linear charge concentration could be used in different size of PE-pipes place vertical on surface and surrounded by air. The results show that the maximum linear charge concentration for single blasts varied between 5-10 g/m, depending on the diameter of the pipe (90, 100 and 160 mm). Maximum charge concentration for the repeated blast varied between 2-5 g/m. In the second part of the paper we study what maximum linear charge concentration could be used in situ for full scale blasting tests in a special prepared test area which later on was dug out after the blastings. Up to 40 g/m could be used without damaging the top of the 160 mm diameter pipes. The increase in methane flow was so low so it could not be measured c4.5 m3/h. The conclusion therefore is that the stimulation of methane flow by explosives is not enough.

Jan 1, 2000

By N K. Jain

"The idea of writing this article is to give correct picture about the technique in blastingindustries based on the safety aspect, basically without effecting the results thereof.Like many other sciences, blasting is rapidly advancing and research scientists are dailycreating new devices which are very reliable and efficient.The theory of explosion and all the respective changes caused by the explosives takingplace during the detonation has been brought up to the level enabling a mathematicalexpression of detonation characteristics even in comparative complex cases."

Jan 1, 1993

By Kirk Yeager

All explosive formulations display some sensitivity to heat. A common technique utilized to measure an explosive’s response to thermal stimulation is differential scanning calorimetry (DSC). As DSC analysis is run on quantities of material easily handled in a laboratory setting, and is relatively inexpensive, it tends to be one of the more predominant tools utilized to determine potential thermal hazards of energetic materials. The analysis of energetic materials via DSC provides unique challenges, as both large energy outputs and significant production of gaseous products result from their decompositions. In addition, the unique thermal decomposition characteristics of ammonium nitrate (AN) based materials have also created difficulties in DSC analyses. A wide variety of techniques have been developed to study the decomposition of explosives. Traditionally, sealed glass capillaries were utilized to house samples. Recently, the introduction of specialty cells designed to withstand high pressures has enabled new sampling techniques to be developed. Analyses of explosives with both traditional and “high-pressure” cells will be compared and contrasted. Lessons learned about the application of both techniques towards analyzing thermal hazards such as incompatibilities will be presented. Inconsistencies in the results displayed during analyses of AN-based explosives will be highlighted. Recommendations on the best approach for analyzing the more problematic AN formulations will be given.

Jan 1, 2000

By Michael E. Kovach

This discussion is an overview of an approach to drilling and blasting angle holes at Martin Marietta Aggregates. Method of determining burdens, hole depths, angle settings and explosive selection will be discussed in detail with an emphasis on safety and production. Such techniques and methods involve the use of hand-held surveying instruments such as the Abney level, pocket transit and inclinometer along with measuring tape and burden pole. An interesting method developed by Oscar Banfield a retired Martin Marietta and E. I. duPont engineer, for setting the proper angle on a drill will also be presented. This treatise is a discussion of the use of simple yet important tools and techniques a blaster should use to resolve both routine and complex problems encountered during quarry blasting operations.

Jan 1, 1992

In situ, most Taconite is heavily pre-fractured; because of the high cost of comminution of taconite, maximum fracture of pre-existing blocks is desirable. Sustained borehole pressure plays a significant role in fragmentation, especially by penetrating pre-existing fractures. The distribution of explosive-induced energy in the burden in three dimensions was calculated. Data on the comminution of single particles was used, with the distribution of energies and the distribution of pre-existing block sizes, to calculate fragmentation for a case study. The calculation agreed well with the measured fragmentation. Sequential comminution events are much more efficient than single ones, and enhanced fragmentation may be possible with alternative blasting practices. Some important factors in the dependence of comminution on energy input are discussed.

Jan 1, 1995

By Shulin Nie, Mats Olsson

The mechanism of rock fracture by explosive is a fundamental in rock blasting. It is generally believed that the shock waves from the detonation initiate the fractures. Then the detonation gases penetrate into the fractures and elongate them. However, our previous researches indicated that the detonation gases do not contribute significantly to the fracture propagation. In our latest experiment, blasts have been carried out in 8 large granite blocks. The main goal was to study the fracture mechanism, namely to determine whether the shock waves or the detonation gases fracture the rock.

Jan 1, 2001

By D T. Froedge

In 1972 the Kentucky State Legislature enacted House Bill 625 which was known as the Kentucky Blasting Law. This law was enacted primarily to stop problems associated with surface mining, but when it was enacted all industries using explosives were included. The bill was assigned to the Department of Mines and Minerals which created a Division of Explosives and Blasting. At that time, this division only had regulations concerning blasting. One should make a distinction between blasting regulations and other explosive regulations. Blasting is the actual use of explosives, the control of the blasting operation, how much is used, at what distances to buildings, the yardage, and other actions associated with the detonating process, explosives regulations generally including safety to the personnel and the storage of explosives.

Jan 1, 1977

By Charles H. Dowding

This paper describes NUVIB, analytical software to digitize, analyze, display, and plot time histories generated by blasting and construction vibrations. It is available in conjunction with a new book on Construction Vibrations (Dowding, 1996) through internet procedures described at the end of the chapter on analytical software These internet based procedures eliminate the need for inclusion of disks in the book and take advantage of the growing electronic communications network. Perhaps more importantly this procedure allows the software to be updated more often than the book is reprinted.

Jan 1, 1997

By Ann Barron

Even though you think your company’s safety program is the best it can be, equipment, processes, supplies, surroundings and people do not always behave or react as expected. Consequently, needless accidents occur each year at quarries, construction sites, surface mines, and other locations where explosives are used. While blasting accidents account for only a small portion of the total accidents reported, the severity rate for blasting accidents is higher than for any other accident category.

Jan 1, 2007

By Fumihiko Sumiya, Yukio Kato, Yoshikazu Hirosaki

Secluential blasting is one of the most popular methods in blasting. tiowever, it is well known that an emulsion explosive can be dead-pressed by dynamic pressure generated by the previous detonation. It is difficult to gain the expected blasting performance due to tb.e malfunction of explosive caused by deadpressing and shock desensitization. Such malfunction of an explosive is undesirable for safety blasting operation. Voids in the emulsion explosives will considerably affect the performance of explosives such as sensitivity, detonation velocity (DV), pressure-resistance and so on. To clarify the detonability and the performance of precompressed emulsion explosives, the DV was measured. Three types of microballoon or micro bubble ; two types of glass microballoon(GMB), resin microballoon@MB) and chemical gas bubble ; were used as sensitizers for the sample emulsion expiosives. The underwater explosion test was carried out to load dynamic pressure into the sample explosives. The dynamic pressure was generated by the detonation of a donor explosive, and the DV of the sample explosives as acceptor was measured by ionized gap terminals. The dynamic pressure level and initiation interval for the donor and the acceptor were chosen as experimental factors. The detonability was carefully investigated at short initiation intervals taking into consideration the interaction between same delays caused by the deviation of the ignition time of the electric detonators. From these experiments, the following results were obtained ; A) The DV of precompressed emulsion explosives was low compared with that of uncompressed emulsion explosives in all pressure conditions. B) The decrease of DV in the sample explosives sensitized by GMB s was larger than that of DV in the sample explosives sensitized by RMBs or chemical gas bubbles. C) The recovery of the detonability occurred rapidly in the sample explosives sensitized by RMBs and chemical gas bubbles. However, a long period was needed for the recovery of detonability in the sample explosives sensitized by GME! s. It was concluded that the type of microballoon and micro bubble significantly influenced the detonability of precompressed emulsion explosives.

Jan 1, 2002

By John F. Mitchell

Large production blasts involving many series in parallel have long been a source of complication. When speed and accuracy are most necessary in blast preparation an efficient and precise method of wiring is required. After loading a large number of holes and being pressured for time, due to lack of daylight, equipment shutdown, etc., an effective hook-up plan can eliminate many last minute problems. It is the intention of this paper to offer a simplified wiring proceedure which when employed can save precious time and encourage efficient and economical utilization of blasting personnel and material.

Jan 1, 1976

By John W. Kopp, David E. Siskind

Over 4 billion pounds of commercial explosives are used by the U.S. mining industry every year with an excellent and improving safety record. However, accidents involving explosives are seldom minor. They produce a disproportionate amount of fatalities compared to other mining activities, as reflected in the relatively high severity rates. The U.S. Bureau of Mines (USBM) has been analyzing blasting accident data obtained from the Mine Safety and Health Administration (MSHA) to determine the most frequent causes of mine blasting accidents, examining trends in these accidents, and identifying areas of needed research. This paper is an update of three previous blasting accident studies conducted on 4-year intervals by the USBM and published in 1983, 1987, and 1991, and is based on a total of 869 blasting accidents.

Jan 1, 1995

By D Reid Watson

A unique blend of theory and hands-on teaching of blast hole drilling and explosives technology is being provided at a Canadian Community College. Students graduate at an apprentice level quite capable of operating and maintaining blast hole drills and designing and executing surface blasts.

Jan 1, 1987

By Stuart Pether, Cedric Goode

The Mt Morgans Minesite is located 800km North East of Perth, the Capital City of Western Australia. The surrounding region has been a significant producer of gold since the turn of the century. The mine was previously host to a township of approx 40 - 50,000 people.

Jan 1, 1996