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By Ann Barron, Mark Abernethy

Along with the immense benefit of modern explosives seismic and acoustic effects caused by their detonation can be disruptive and alarming to many people. Claims range from affecting sexual performance to outright demolition of a residential structure. Regardless of the quality of the blast design and other precautionary measures, the inherent danger posed by the use of explosives often leaves residents searching for restitution. Consequently, many blasting companies today find themselves at the center of litigation. In the event that a blasting complaint proceeds to litigation your case will not be decided on “reasonable doubt” as in criminal trials. Instead, the jury will be instructed to decide guilt or innocence on a “preponderance of the evidence” presented. Even if you are able to present the best and most complete evidence that you have not caused the claim, the jury may rule in the favor

Jan 1, 2004

By Jack Elorenta

We often hear that, "Blasting was an art, but now blasting is now a science". 'Scientific' blasting implies that we have quantified and reproducible measurements of the feedstock and product of the blasting process. However, the industry's reluctance to adopt two key technologies, drill monitoring and optical size analyzers, sheds doubt on the claims of scientific blasting.

Jan 1, 2003

By Tristan Worsey, Nathan Rouse

The Florida legislature allocated funding for the Florida State Fire Marshal (FSFM) to review the applicability of the United States Bureau of Mines (USBM) Report of Investigations (RI) 8507 blast vibration limits with respect to Florida and its soils. The study also discusses whether the current blasting vibration limits set by statute are still appropriate, including a review of measured vibration amplitudes and frequencies, structure responses, and theoretical analyses of material strength and strains

Jan 1, 2019

By Martti Hagfors

The Finnish Defence Forces Technical Research Centre (PVTT) studied the effect of shape of boost-er to its ability to ignite insensitive (IM) plastic bonded explosive (PBX). Therefore an explosive fac-tory produced 20 insensitive (IM) plastic bonded explosive (PBX) charges for the tests. The mass of each of the charges was exactly 9.2 kg (20.3 lb). The charges were equipped by two different type of boosters; RDX and PETN. Both the explosives contained some parts of plasticizers. The weight of all the boosters was exactly 300 g (0.66lb). On the bases of their shape, the boosters were also divid-ed into two different groups, cylindrical and “pancake”. In the middle of the “pancakes” there was also shaped a small cone in such away that the detonation could accelerate to its full speed after the charge was ignited. The following shots were exploded;

Jan 1, 2013

By C. Anderson, Mike Michaelis

Ammonium Nitrate (AN) - based commercial explosives are non-ideal explosives. This is because the chemical and physical structure is heterogeneous on a distance scale comparable to, and in many cases larger than, the reaction zone in the detonating explosive. Such systems consist of inter-molecular fuel-oxidizer systems. Attempts have been made to minimize the heterogeneous nature (inter-molecular distances) of these explosives; emulsion systems are the latest examples of these commercialized AN-based explosives which balance cost, utility and performance. This latter factor (increased performance) is a direct result of increasing the contact between oxidizer and fuel.

Jan 1, 2003

The common approach of designing blasts on a trial and error basis is quickly coming to an end. When utilizing the full scale blast environment, trial and error can quickly become cost prohibitive and leaves much to be desired in terms of true blast diagnostics. In these situations testing is usually only continued until a perceived improvement is achieved and when the gross undesirables in blast results are removed. This does does not preclude, however, that further improvements of up to 100% or more can not be obtained.

Jan 1, 1991

By Robert B. Hopler

The history of the first twenty years of the high explosives industry in the United States begins as an illustration of the free enterprise system at its best and ends with the industry virtually taken over by a single company: a company which strongly opposed the new explosive material at the beginning of the period. In the world of the late Twentieth Century we could almost compare this history to the opposition of the mainframe computer manufacturers to the introduction of the personal computer, and their later entry into, and attempted dominance of, that market. With computers in the twentieth century the attempt to dominate the market has not been particularly successful: with dynamite in the nineteenth century it was.

Jan 1, 1994

By Stephen H. Chung, Kevin Atherton

The main purpose behind this preliminary study was the reduction of costs while maintaining productivity. Finding a way to achieve this balance without compromising controls on safety and quality of blasting results is of continual interest to the mining industry and of particular interest when ore of lower grade is being mined.

Jan 1, 1998

By Clarence R. Zink

A problem has always existed in deep and fast drilling situations such as coal overburden drilling, or when drilling with a tight annulus, such as 9 7/8" bits and 8 5/8" pipe. This problem is the difficulty experienced by blasthole bit and blasthole drill rig manufacturers to attain large jumps in bit and drill rig productivity through bit and rig design, when drilling in these specific situations. In other drilling situations, these large jumps in productivity have been easily attained.

Jan 1, 1998

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Umit Ozer, Kagan Ozdemir

In the condition that drilling and blasting technique is inevitable depending on the rock mass and material characteristics on mining activities, the fragmentation rate and particle size distribution of the muckpile after blasting has important influences on the performance of subsequent mining activities such as loading, hauling, crushing, grinding etc. and the total costs of that mine. Drilling and blasting is an important step in this process chain and it's results such as fragmentation, muckpile shape and looseness, dilution, damage and rock softening effect the efficiency of downstream processes. There is an increasing body of blasting research indicating significant impacts in these downstream processes.

Jan 1, 2007

By M. Hagfors

When establishing an underwater testing site for the energy measurements of the explosives, the dimensions of the measuring pool have to be measured to find out what is the maximum weight for the test charge. Secondly one has to decide the distance between the pressure gauge and the shooting point. Thirdly the pool has to be calibrated because of the reflections of the explosions by measuring the bubble periods of the calibration charges. The calibration shots can also be used to estimate the minimum weight of the explosive charge for the reliable energy measurements by calculating the shock, gas heave and total energy values and their standard deviations.

Jan 1, 2007

By Mark A. Williams, James D. Humphrey

Without question, draglines are one if not the most effective tools available to the surface mining industry for overburden handling. With few moving parts and a two- or threeman crew, this machine silently sits and chews into millions of yards of overburden annually. A 100 cubic yard machine operating for 30 years will excavate three-quarters of a billion yards of material during that time. That is 750,000,OOO yards of material!

Jan 1, 1990

By Dale S. Preece

"The computer program DMC (Distinct Motion Code) [Taylor and Preece, 1989a] was developed in 1988 and 1989 to predict the motion of rock following a conventional blast. DMC executes very efficiently on a CRAY type computer due to the high degree of vectorization and also due to the use of spherical elements [TayIor and Preece, 1989b]. Bulking mechanisms developed specifically for use with spherical elements include rotation-induced dilatation and aspect ratio > 1.0 [Preece and Taylor, 19901. Rotation-induced dilatation allows the radius of the sphere to expand as a function ofsphere rotation to simulate the interaction of corners and sides of blocky rocks. An aspect ratio > 1.0 is achieved by kinematically tieing spheres together."

Jan 1, 1991

By Don McCarthy

Modern mining has been dominated by the drill-and-blast method for more than a century. There have been steady improvements in drilling technology, explosive products, methods of initiation and integration of the two techniques but the essential cyclical nature of drill-and-blast rock excavation naturally limits continuous improvements in cost and productivity. Dynamite and safety fuses, compressed-airdriven tools, and most of the crushing and grinding machinery in use today were all developed before 1900. Moreover, virtually every mechanized mining system used today was in use by the late 1950’s.

Jan 1, 1998

By Tom Short

"Construction blasting covers a very extensive variety of explosive applications. I will discussseveral of these with you and then show slides from my collection, starting in 1956, which will betterillustrate the types of blasting under discussion."

Jan 1, 1991

By Pierre L. Labelle

Non electric Dual Delay initiators have revolutionized many aspects of underground mining. The units are used in all types of underground blasting operations. Some operations, due to the complexity and variety of their blasts, have extremely large inventories of conventional non electric products. The Dual Delay system has drastically reduced these inventories and has added an important element of versatility to blast designs.

Jan 1, 1994

By Thomas E. Brown

Commercd explosives have evolved through this century f?om dynamite through ANFO to the current lines of Water Gels and Emulsions. Water Gels and Emulsions evolved to counter the lack of water resistance and density of ANFO yet maintain its low cost position verses dynamite. Today, explosives must be safe and inexpensive and perform under a wide range of temperatures, function efficiently in wet or dry boreholes and have a good shelf life. Emulsions meet this criterion, which is why they are the current trend products worldwide.

Jan 1, 1998

By Robert Boehnke, Bernd Mueller

Despite enormous efforts over the last decades there are still many unanswered questions with respect to calculation and modeling of the blast process using appropriate physical laws. Most calculations of explosive charges of a blast design are based on experience, empirical observations or blasting theories with serious shortcomings. This paper presents a new theory for the design and calculation of a rock blast that is based on the momentum. It offers a clear-cut method for the calculation of blast processes. The theoretical results will be compared with on-site measurements by means of a newly developed strain sensor and further measuring equipment. The momentum theory helps better to explain physically the processes of a blast. On the basis of long-term statistical investigations a momentum balance can be carried out with the volume-based blasting momentum and the measurable momentum associated with the muckpile and the remaining rock mass. This type of consideration requires a complex procedure which includes the blastability of the rock masses. Realis tic strain measurements open a new interpretation possibility and judgment criteria for the most probable building damage, the dynamic impact on general types of buildings and also for the blast process itself. The blast-induced stress and the momentum generated could be back-calculated using a geophone profile and the strain sensor. The strain owing to a dynamic impact can be influenced by the changing of the drill-, blast- and shotfiring technique like the until now measured vibration velocity. In this way it is possible today to make a complex preparation, calculation and evaluation of blasts. The new techniques of measuring in connection with the momentum theory bring about an increase of the safety and a clearcut method of improving the blast processes. This procedure offers new possibilities for the precise calculation, simulation and modelling of blasts and resulting vibrations and leads to an increase of the safety as well as economic adaptation of the drill-, blast- and shotfiring techniques to a pre-determined blasting result.

Jan 1, 2003

By Barend Botha, Trevor Davids

The presence of an extensive soft siltstone layer in the middle of the inter-burden sequence of rocks at Syferfontein Colliery in the Republic of South Africa prompted tests to determine the effect of different mid-column decks of inert material in the siltstone layer. The objective was to achieve significant cost savings in explosives use whilst not degrading dragline productivity. An important factor that had to be considered was that the initiation systems available in South Africa are not accurate enough to ensure simultaneous initiation of explosives decks in a blasthole. A number of inert materials were tested including ash, drill cuttings, river sand and crushed stone. It was found that the ash, drill cuttings and river sand did not effectively attenuate the shock wave and that the risks of sympathetic detonation or partial disruption of one or the other explosives deck in a blasthole was high. This became much worse when the inert material was saturated with water. Crushed rock was the most effective in attenuating the shock wave, but this material was very expensive to use because it had to be imported onto the mine.

Jan 1, 2000

By Russell Carter, Tom Barkley

"Optimization of blasting is hampered by the lack of inexpensive methods of measuringblast results. Optical methods of size analysis have the potential of creating abreakthrough in size analysis and in overall blast optimization. Attainment of reliablemeasurements hinge on solving a number of shortcomings inherent to optical systems."

Jan 1, 1999