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By David Lilly

The introduction of electronic caps with significantly more precise timing is forcing an examination into the practical effects of timing precision upon vibration, air blast, fragmentation and crusher productivity. These investigations have produced suggestions that techniques using multiple delays of the same period with conventional detonators might approximate electronic high precision.

Jan 1, 2006

By David Willock, S. Singh, Michael Glogger

The efficiency of the loading system in a mine depends upon the characteristics of the muck pile, the loading machine specifications and the loading practices. The focus of this paper was to look specifically at the size distribution of blasted material, and to quantify its effects on loader productivity. A scale model of LHD was designed and fabricated to represent machines currently employed in the industry. The experiments were performed using crushed Gabbro, which was mixed in various proportions according to Rossin-Rammler size distribution to give five different characteristic particle sizes and five different size distribution constants for each characteristic particle size. The effect of the size distribution constant on peak and mean penetration forces, work done and bucket fill factor was examined. In addition, the influence of mean particle size, 80% passing size (D80) and % oversize on the penetration force and bucket load was investigated.

Jan 1, 2001

By Alastair Grogon

Proper coupling of a geophone to a monitoring surface is probably the single most important step in accurately recording and measuring ground vibrations from a blast. Over the years, a number of monitoring methodologies have been published. Some of these were published as a "standard", by organizations such as the International Standards Organization, others as suggested methods by various authors in papers or text books, or in the users manuals supplied by seismograph manufacturers. These monitoring standards differ, and are sometimes apparently contradictory. The purpose of this paper is to summarize the coupling methodologies from a number of these "standards", point out similarities and differences, and discuss the technical basis behind some of the different methods.

Jan 1, 1998

By Callie Covert

This paper describes the application and results of a more efficient method of breaking boulders using dynamite and water. This method is being used for the disposal of boulders that result from pinnacle and cap rock remaining after blasting on highways and job sites. This method is a faster and less expensive use of dynamite to reduce oversized boulders than the conventional rock hammer. The problem with excessive fly rock has been substantially reduced when using this technique over traditional methods.

Jan 1, 2001

By Jeffrey A. Straw, Joseph P. Jr Shinko

Ground vibration produced by blasting operations within South Florida, due to saturated soil conditions, generates surface vibration waves that may be measurable over distances of 3 - 5 miles from the source, and perceptible at distances of up to 2 miles. Structures above ground usually receive the most of the attention from the effects of high vibration levels. During construction of the Trilogy Development of the Swerdlow Companies, blasting was completed in a lake excavation immediately adjacent to the City of Pembroke Pines Utility Department, Deep Injection Wells No. 1 and No. 2.

Jan 1, 1994

By James Barker, David Leidel, Don Crawford, Daniel Dorffer

This paper describes the test processes performed to ensure the suitability of an RF-safe detonator for use in oilfield explosives operations on land and offshore locations where RF silence cannot be implemented or the distances from explosive systems arming operations to the RF source or sources are too close for conventional resistorized hot-wire detonators based on the safe distance tables. The test program for the detonator assembly was based on MIL-STD-461E, “Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment”, 20 August 19991.

Jan 1, 2008

By John L. Floyd

A personal computer is a valuable tool for blast design and analysis. Programs designed for the personal computer, such as the electronic spreadsheet, can be used for a wide range of applications. The spreadsheet formats discussed in this paper are used for explosive comparison, inventory/shot records, and timing design analysis. Each template can be adapted to fit the individual needs of the end user. An example of a graphically orientated blast design program, written in the BASIC programming language, is also discussed.

Jan 1, 1987

By Paul D. Dupree

This paper discusses the drilling and blasting techniques used in blast casting at a large western coal stripping operation.

Jan 1, 1986

By Cam Grundstrom

The Ok Tedi Mine is a large open pit copper and gold mine located in a remote section of the Western Province, Papua New Guinea, with an annual rainfall of over 10 metres. Ok Tedi mines an average of 205,000 tonnes per day. A strong working co-operation between the mine operator (Ok Tedi Mining Limited) and the explosives contractor (ICI Explosives Asia / Pacific) has led to progressive development of bulk emulsion formulations to meet site-specific needs, continued improvement to blasting applications, and competency based training programs for the national blast crew.

Jan 1, 1997

By A T. Spathis, J J. Felice, T A. Beattie

High speed cinematography of surface blasting operations is used for diagnosing various aspects of blast performance. Several quantitative features may be derived including confirmation of the hole initiation sequence, time to first movement, evidence of stemming ejection and measurements of face velocity. Face velocity measurements using high speed cinematography have the following disadvantages: firstly, for accurate measurements placement of targets on the face and surveying of them is necessary; secondly, the analysis requires experience and time and can only be done after the film has been developed.

Jan 1, 1991

By George P. Schivley

When drilling blast holes, with roller cone bits, a phenomenon known as drilling vibration can occur. It is characterized by either axial or lateral modes of periodic motion of the drill pipe; superimposed on the time-average angular motion of the drill pipe provided by the drill rig rotary head and the vertical motion associated with the penetration rate of the tricone bit into the rock being drilled. This periodic motion can be very severe and, if appropriate action is not initiated by the drill rig operator, could lead to structural damage to the drill rig. Ultimately, the occurrence of drilling vibration limits the productivity potential of a rotary drill.

Jan 1, 1997

By Kenneth Medearis

There is considerable evidence that more rational damage criteria need to be generated with regard to low-rise structures subjected to blasting vibrations. There is not sufficient basis for specifying a maximum ground particle velocity damage criterion such as 2 inches/second. A peak ground velocity guideline does not currently take into account a number of significant parameters, including the predominant frequencies of the ground motion excitation and the structure being excited. Although a number of states have adopted, or are adopting, maximum particle velocity criteria, such criteria have been ruled inadequate in certain legal decisions affecting blasting operations. The development of more rational damage criteria is thus of significant importance.

Jan 1, 1978

By Edward J. Walter

Our modern technology is provided with a unique but flexible power tool in the use of explosives. A by-product of explosives usage is vibration or elastic deformation of the earth which is annoying to the ordinary person and can be damaging to structures. The problem is not new, it is more than fifty years old. Adequate vibration standards have been developed so that blasting programs can be properly planned and safely executed. Changes in our social culture have somewhat changed the emphasis in blasting vibration from damage considerations to the much lower level of citizen annoyance. Vibration codes based on this level will be highly restrictive and prohibitively costly. Cooperation is urged between operators, community officials, agencies at all levels,and consultants to see to the development of sound realistic vibration codes.

Jan 1, 1975

By Donald C. Clark

The Blasting Contractor as an Insurance Risk involves a discussion of changing times in the insurance market and changing methods of operation in the construction industry. Since the advent of Internal Revenue Service~1 and Occupational Safety and Health Act~2 regulations by the Federal Government in the early 1970's, operations have changed. Many small users of explosives have discontinued any use in favor of subcontracting the drilling and blasting to specialists. This change in operations along with the change in the insurance market has created coverage problems which is the subject of discussion of this paper. Although no definite conclusions are reached, it is an attempt to promote understanding and further the efforts toward equitable solutions.

Jan 1, 1977

By Peter F. Bayer, Fred C. Drury

This paper deals with explosives regulations in the State of Wisconsin. As has been typical elsewhere, there has been considerable pressure to add additional restrictions over blasting in Wisconsin. What we believe to be a novel approach to the problem has been developed and is being implemented. Members of this Society have been instrumental in this approach whereby the emphasis of the regulations is directed at permissible levels of blasting resultants rather than at specific methods of blasting. It is our intent that this paper serve as a guide to others who may become involved in similar regulatory review in other states.

Jan 1, 1984

By N K. Jain, Rajesh Jain

This article has been written indicating the present trend in Blasting all over the World, so as to help in planning production and development of Industrial Explosives for the development of industries in all the countries in general

Jan 1, 1992

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 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 R H. Stevenson

This paper deals with a new variation of the cast blasting technique, where-in the object is to cast the economic deposit out front under the overburden, while avoiding dilution from the floor material. To date, the technique has been successfully applied at two cement quarries in Iowa and at a granite quarry in Minnesota.

Jan 1, 1991

By Paul Downing

While safety and security have always been concerns of the U.S. explosives community, events throughout the world during the past few years have caused us to re-examine our industry’s potential vulnerability and change the way we do business on a day-to-day basis.

Jan 1, 2006