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By John C. Brulia

Blasting is both an art and a science with the primary objectives being safety and performance. Safety, the paramount objective, is a process that has limitless opportunities for improvement. Quality, a concept espoused by world-class corporations to competitively meet the needs of customers for goods and services, can be adapted to the explosives industry to improve blasting safety.

Jan 1, 1993

By Mauro Fornaro, Marilena Cardu, Renato Mancini, Daniele Castano

Tunneling by explosive blasting in civil works isn't merely intended to break somehow a way through the rock, rather to drive a permanent, constant cross section, lined way. The current mechanical excavation v/explosive blasting debate is mainly centered on the concept of the tunnel wall quality; and consequently explosive blasting strategy is founded on contour blasting.

Jan 1, 1992

By John T. Day, Lex L. Udy, Mark L. Thomas

When we consider that the purpose of blasting is to fragment rock or ore so it can be subsequently handled and processed, we can see that the cost of blasting, in reality, affects all downstream steps of the mining (and in some cases) production processes. The productivity of all subsequent operations is influenced by the degree of fragmentation of the primary blast.

Jan 1, 1987

By Hike Humphreys, Geoff Baldwin

A project aimed at blast optimisation for large open pit coal mines is utilising blast monitoring and analysis techniques, advanced dragline monitoring equipment, and blast simulation software, to assess the major controlling factors affecting both blast performance and subsequent dragline productivity. This has involved collaborative work between the explosives supplier, mine operator, monitoring equipment manufacturer, and a mining research organisation.

Jan 1, 1994

By Ryan Redyke, Jared Redyke

The demolition of an old power plant boiler house in Parsons, Kansas calls for the use of some linear shaped charges. The steel is thick and the structure is heavy but gravity can be a blaster’s best friend. This entry did not win in a very competitive category. We thought it was worthy of coverage in the Journal of Explosives Engineering.

Jan 1, 2015

By Rowland Jones

This type of quarrying is very much different from that of established quarries in developed countries, demanding somewhat unorthodox techniques to produce the variety of materials required. The demands on the resourcefulness of-the quarrymaster can be very testing, and produces quite a different breed of individual than what is normally met in managerial status in quarries of developed nations.

Jan 1, 1977

By Timothy Stark

At present blasters are strictly liable under tort law for personal injury and property damage caused by ground vibrations and/or air overpressures. The application of strict tort liability to vibration and air overpressure damage has resulted in litigation that has hampered and probably will continue to hamper the blasting industry. There are many case histories in which blasters have been sued for the appearance of cosmetic cracking, some of which have involved frivolous claims and marginal expert testimony (Oriard 1999). This litigation has resulted in additional costs to the blasting and construction industries and the American public because there are usually many plaintiffs involved and each case is usually adjudicated separately instead of under a class-action format. It is proposed herein that blasters not be held liable for vibration or air overpressure damages unless their conduct is proven to be negligent. A number of reasons are presented for raising the legal standard from strict liability to negligence including: (1) improvements in blasting technology that allow blasting to be conducted without substantial risk of damage and if damage does occur it is likely to be cosmetic, (2) establishment of conservative ground vibration and air overpressure damage limits for typical structures, and (3) established industry standards for construction blasting.

Jan 1, 2002

By David Harrison, Brian Harrison

The Army Corps of Engineers completed the Charleroi Lock and Dam in 1932. It is located on the Monongahela river approximately 22 miles (35k) south of Pittsburgh in Charleroi, Pennsylvania. It is comprised of a 420-foot (128m) gated dam, and a 720-foot (219m) by 56-foot (17m) land side lock, which provides for a 16.6 foot (5m) vertical lift.

Jan 1, 2018

By Tom Hale

Developers and blasters are faced with increasing public demand and regulatory restrictions to maintain the lowest possible levels of noise and vibration from blasting operations in populated urban areas. Pyrotechnic products have proven to be a low noise, low vibration alternative to conventional blasting for close-in rock excavation and concrete demolition applications. Pyrotechnic breaking charges often yield 1/10th the vibration and noise compared to traditional explosives, and have been demonstrated to increase public confidence and decreased damage potential where they have replaced explosives, thus allowing new opportunities for work and greater job profitability. This paper presents a practical approach to utilizing pyrotechnic products in various applications including trenching, mass excavation, demolition, and dimension stone production, providing methodology for pattern design, vibration probability and loading calculations. Field research data is reviewed and compared to conventional explosives.

Jan 1, 2008

By Don Houston

Vertical crater retreat mining (VCR) requires initiation methods that minimize debris in the borehole. The use of detonating cord and shock tube detonators eliminates debris that could interfere with subsequent loading operations and avoids the cost of using drilling equipment to clear the debris. The explosive must not be sensitive to the strength of detonating cord used, otherwise timing will be affected. “Slicing and Dicing” of product before “Air mailing” down boreholes may facilitate loading, especially in wet holes, and can result in product surrounding the detonating cord. Cord sensitivity testing confirmed that having the detonating cord surrounded by product significantly increases the likelihood of an energetic reaction. Careful formulation and testing, based on a thorough knowledge of the application and the role of ingredients in affecting performance, ensures reliable initiation and avoids cord sensitivity. The use of certain metallic nitrate salts, even in relatively small amounts, was found to significantly increase the cord sensitivity of watergel formulations. Evidence of increasing cord sensitivity includes increasing amounts of damage to product and packaging, to ejection of product from the test pipe, then cracking of the pipe, followed by deflagration then detonation of the product. Predictably, the likelihood of an energetic reaction increases with product temperature, cord strength, and borehole diameter, while it is inversely related to product density.

Jan 1, 2002

By Robert C. Brown

During a research period lasting over three years, a vast number of seismograms were collected and analyzed. From this data, other than obtaining a host of new information pertaining to the effects of surface mine blast on underground mines, it was found that by mounting seismograph velocity transducers at the center of crosscuts in underground mines, seismograms can be obtained which give fairly accurate information about the maximum levels of vibration, and the associated Of stresses and strains, misfiring of blast holes, delay accuracy and delay overlap. The technique of analysis is a simple one; it involves matching of the frequency of wave or wave groups with the shot card information such as rows of holes, number of holes and the cumulative milliseconds of delays used in the blast holes. Any discrepancy that might exist between the frequency of waves and the expected cumulative millisecond delay for a given row or hole eventually will show up as a mismatch in the analysis. This simple technique enables the seismographer to be involved not only in the monitoring of blast peak vibration, but also in making recommendations as to the choice of millisecond delays, reducing the possibility of delay overlaps and reducing the hazards of blast hole cutoffs.

Jan 1, 1980

By Frank Hammelmann, Peter Reinders

This paper briefly describes the past history of blast management. A modern blast management suite is then presented which demonstrates the current capability of the functional link between an electronic blasting system and blast design software. Finally, we look at the potential of tomorrow’s fully integrated blast management systems. From the first time blasting was introduced in mining as part of the production process, blasting technology and blast management have been interconnected. Over the past decades we have gained more recent experience with the new electronic blasting systems in mining, quarrying and construction. To start, the primary focus of electronic blasting was to increase timing accuracy. However, since then the technology has gradually developed, broadened and opened up new possibilities, including impressive flexibility in blast design and full in-situ verification of system functionality. To support this capability, modern electronic blasting systems are specifically designed to facilitate full two-way transfer of information between the office-based blast management software and field-hardened equipment. Blast management systems now comprise a suite of expert systems for planning, documentation, analysis, measurement and prediction of blasts. Within this blast management suite, the blast design software allows the transfer of the blast design information from a PC directly to the hardware of the electronic blasting system. The future development of this technology holds huge potential for the blasting industry.

Jan 1, 2004

By Michael S. Wieland

Delay detonators that are damaged by cross-hole wave interactions degrade blasting work and raise the risk of incidents. Damaged detonators impose risk, because they can retain sensitive explosives that respond to stray energy during recovery, inspection or disposal. Laboratory techniques were developed to rank the ruggedness of delay detonators under replicated field-shooting conditions. The hazards are tremendously magnified if trial detonators are installed directly in secondary explosives to rank initiation strength. Therefore indirect ranking techniques were sought that mitigate the risks without compromising the worthiness of the method. Four types of hardware fixtures, referred to as simulators, were developed to yield distinct forms of transient compression. The shock and rift versions generate compression pulses representative of in situ waveform components. The waiting time, until the trial detonator functions, duplicates typical delay periods. The trial detonator is mounted within water, which has a density and inertial resistance comparable to most blasting explosives. The work output from the trial detonator explosion is registered as fixture wall-expansion. This work output determines malfunction results, regardless of which type of simulator is used.

Jan 1, 1997

By John C. Didlinger, John L. Didlinger

As we begin the pre-blast survey we need to decide on the number of holes needed for production and a detailed highwall inspection. The survey consists of checking the highwall and placement of barrier cones. At the Elmhurst Chicago Stone Company, Barbers Corner Plant, we use 18-24" orange highway type safety cones. These cones are easily noticed because of their high visibility color in all weather conditions and are placed approximately 20-25 feet from the face and approximately 50 feet apart along the highwall, then the area is checked for back break, under cut, over hang, surface filled area and clay area. This deposit is unique because of the number of clay filled areas and slip seams that meanders through the deposit plus a fault that runs North-Northwest and South-Southeast. This particular limestone deposit is overlaid with glacial sand and gravel and the top weathered stone wanders plus or minus 10 feet in 1400 feet.

Jan 1, 1996

By Gordon M. Matheson, David K. Miller

Sinkhole development in karst terrains is a serious problem and risk to facilities built in these areas. The potential for sinkholes are a function of many things including the chemistry of the underlying rock, the location of water conductive fractures and fissures in the rock, the natural fluctuation of the ground water table, vibrations from various sources and surface regrading activities. When sinkhole open near quarry operations the occurrence of these features is occasionally attributed to vibrations from quarry blasting. The purpose of this paper is to review the evidence regarding the development of sinkholes as a result of quarry blasting. In general, it has been found that sinkholes result from collapse or piping of overburden soils into cavities or caverns developed within underlying carbonate rocks that have been in existence for many thousands of years. The overburden soils in karst areas are typically clayey and as a result are not subject to densification or liquefaction as a result of vibrations. The primary cause of an increased rate of sinkhole development can be attributed to changes in the ground water table or local surface water drainage. These changes may be caused by seasonal fluctuations, ground water level lowering in drought periods, dewatering of excavations or quarries, or local changes in surface drainage resulting from grading activities.

Jan 1, 1998

By Keith Pucalik

One of the more important duties of the vibration consultant is to evaluate allegations of blasting damage by neighboring property owners. Unfortunately, the consultant is generally faced with having never seen the project, or preparing for litigation three or more years after blasting was completed. Under these circumstances, he must rely totally on blaster's logs and other contemporaneous records to conduct a meaningful evaluation.

Jan 1, 1990

By Yu Yalun, Meng Chuyan, Wang Lin, Wang Deshang

Based on the analysis of problems with wall control blasts in open pits, the essential theoretical basis and technological design of the damping presplit blasts are put forward. After practical application of this method in Nanfen Open Pit China, very good results have been achieved: 1) The rate of decreased vibration is up to 40%; and 2) The damage area of slope is reduced about 60%.

Jan 1, 1998

By Li Jianjun, Zhang Xiaozhi, Guan Li, Jin Jinzhe

People used to regard emulsion explosives as the safest industrial explosives. But in the process of manufacturing emulsion explosives spontaneous ignitions of the remnant emulsion matrix have happened under the conditions of constant or low temperature. These fatal accidents show both emulsion explosives and emulsion matrix may involve hidden danger. Since the temperature in its production emulsion matrix is high, emulsion matrix is sensitive to mechanic action.

Jan 1, 1998

By J Lyall Workman, Peter N. Calder

Large hole rotary drilling is one of the most common methods of producing blastholes in open pit mining. Large hole drilling generally refers to diameters from 9 to 17 inch (229 to 432 mm), however a considerable amount of rotary drilling is done in diameters from 6½ to 9 inch (165 to 229 mm). These smaller diameters are especially prevalent in gold mining and quarrying.

Jan 1, 1996

By Zhang Zhenyu, Wu Xinxia

The blasting quarrying technology of rock material of rock-fill dam is one of the more complex problems in the field of engineering blasting at present. The Kuz-Ram model is not suited to predict fragmentation distribution under the geology condition of Tianshengqiao(TSQ) fist-step power station. The modification of kuz-Ram model is discussed. With reference to the idea of model establishment of Kuz-Ram model and according to the results of experimental blasting in-situ, two fragmentation prediction models-TSQ-1 and TSQ-2 model are presented which are adapted to the particular condition of rock material querying blasting of rock-fill dam with concrete facing of TSQ first-step power station. The rapid judgment method of qualified grade material and the method of optimizing blasting parameters are also presented in this paper.

Jan 1, 1998