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By Charles A. Kliche

The Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) established a national program for responding to releases of hazardous substances into the environment. The funding mechanism for this program is the Hazardous Substance Response Trust Fund (commonly referred to as Superfund), which provides funding for the implementation of removal and remedial response actions.

Jan 1, 1997

By Kazuyoshi Kawami, Fumihiko Sumiya, Kunihisa Katsuyama, Yuji Ogata, Koichi Kurokawa, Yuji Wada

When explosives are detonated in the borehole where there is an air gap between the explosive charge and the borehole of inner wall, the shock cave in an air gap travelling ahead of the detonation front sill be generated. This shock wave is called the precursor air shock wave (PAS). The explosive is precompressed by the PAS, and as a result of that the detonation failure occur on occasion. This phenomenon is well known as channel effect.

Jan 1, 1994

By Richard Arsenault

The production of oil & gas from wells requires method of flow from the producing formation into the well bore. Once the well is drilled it will have casing pipe installed to protect the integrity of the well formations and means of delivery to the surface. Once casing pipe is installed it will be cemented in by pumping cement through the annulus of the casing pipe down to the bottom of the well and allowed to flow outside the casing pipe up into the formation.

Jan 1, 2007

By Tom Donnelly, Roger C. Ilsley

Remote telecommunications seismographs were used to monitor blast vibrations at two historic structures in Cedarburg, Wisconsin during adjacent sewer line construction. The purpose of the vibration monitoring program at the historic structures was to maintain blast vibrations below limiting tolerances established by the Wisconsin State Historic Society.

Jan 1, 1991

By R Yang, D B. Kay

"Blast vibration control is of vital importance for tunnel blasting in urban environments. A vibration model with multiple seed waveforms (MSW) as input for a point of interest was developed in recent years by one of its authors. The MSW blast vibration model has been applied successfully in open cut and quarry blasting situations. From the literature, it appears that there may not be any seed wave-based vibration modelling work for tunnel blasting.A project was conducted to test the MSW model for tunnel blast vibration. A series of tunnel blast rounds were fired and tri-axial vibration waveforms from the blasts were recorded with several seismographs at distances ranging from 10 to 100 metres from the blasts. Seed waveforms were collected and the charge weight scaling law for the signature hole PPV were established.The MSW model is applied to tunnel blasting and specific issues associated with tunnel blast vibration addressed, such as variable effects of confinement and screening to vibration during a blast round. The capability of the model in terms of the PPV and frequency prediction is demonstrated in the paper. The paper demonstrates that the MSW blast vibration model is a useful tool for managing tunnel blast vibration with the potential to optimise round by round design in terms of managing the vibration below the limit while maximising tunnel advance rate."

Jan 1, 2011

By W C. Brukle

Our title for this presentation could be taken in many ways. One course would be terrifying and that would be to cite incredibly bad practices. All of our votes/efforts should be for the reverse direction in which everyone does his/her best to keep their pit or working place free from hazards.

Jan 1, 1983

By Alain Blanchier, Pascal Bernasconi

Blasting operations took place on Channel coast NW of France to extend Flamanville Nuclear Power Plant (EPR new generation). The closest operating reactor building was monitored by a 24 remote vibrations transducers network to fulfil, on one hand, the severe environment constraints and satisfy high degree of productivity required by the project, on the other hand. Although these requirements usually are incompatible, this challenge compelled to introduce a seismic modelling technique to optimize blast designs using electronic initiating system. The “Hybrid Seismic Modelling” (MSH) uses blastholes signatures (seismic vibrations records) which are greatly dependent on geology and alteration of rock mass, explosives, charge geometry, blast configuration, and the final excavation shape. In order to respect severe vibrations limits, excavation layout was divided into areas with specific blasting modules - type and number of charges, single charge, initiating sequence. Thanks to this technique, it has been possible to reach lowest blasts vibrations levels and a better productivity compared to classical blasting operation at the same location in the past. After the modelling method presentation - principle and use precautions, technical improvements are reported.

Jan 1, 2008

The underwater explosions have been used for several decades for the determination of energy content of explosives. This test method is the only one by which shock, fly rock and total energy can be measured separately. It enables to develop the energy content of explosives for different purposes; the military high explosives should contain more shock energy whereas the fly rock energy is very important feature for the blasting explosives. The purpose of this study was to establish a test place for the underwater experiments in an old water filled open pit, to estimate the repeatability of the energy measurements, to calculate the standard deviations and to compare the total energy content of commercial explosives to the theoretical values calculated by the thermo dynamical program. The test method seems to work quite well especially for the homogeneous explosives. The difference between the energy content of theoretically calculated and measured values for the homogeneous emulsion explosives was about -3% and for the dynamite about -5%. The energy difference for the unhomogeneous ANFO was detected to be -19%. The diameter of the charge was 15 cm and it was obviously too small for ANFO to detonate ideally. On the basis of the test results this test method seems to fit best for the cap sensitive, completely homogeneous, spherical charges whose masses are big enough and which are initiated from the centre of the charge. The underwater explosions as a test method is the only one which can separate shock, bubble and total energies from each other and therefore makes it possible to develop the properties of explosives for different purposes which is very important feature of this method.

Jan 1, 2005

By Tapan Goswami, Geoff Keith

"At Bulga Coal, the objectives of drilling and blasting are to maximise safety and to minimise the totalcost of mining. A recent audit of two overburden blasts established that the standard of drilling and blasting is excellent. No apparent hazards were identified. Laser profiling showed that highwall free faces are reasonably planar with some exceptions, thereby promoting uniform burden distances along front-row charges. However, in three isolated areas along one face, small burden distances existed. The mean and the standard deviation of errors in the collar positions of front-row blastholes was found to be 0.3 + 0.03 m. A borehole video camera was used to show that blastholes did not feature open bedding plane partings, cavities or damage produced by the blast in front of them."

Jan 1, 1999

By John L. Floyd

The use of explosive energy to displace overburden or waste material can provide substantial savings to operations which normally rely on mechanical means for material removal. To optimize the available explosive energy, it is important to quantify the rock's response to the type of explosive and explosive accessories used. During a blast, rock breakage and movement occur so rapidly that the naked eye cannot detect the details of the fragmentation process. A relatively high speed motion picture camera (500 frames per second) can provide the extended time base needed to analyze in detail the site-specific rock response to the explosive detonation. The data of importance to blast casting that can be quantified from these films includes initial face movement, trajectory of rock, and differential face velocities of the material shot. In addition, the ground swell velocities, stemming confinement, and stemming ejection velocity can be determined. The performance of explosive products and delay element accuracy can also be ascertained. The use of high speed motion picture photography and analysis can reduce the number of field trials necessary to maximize explosive performance and increase the benefit provided by blast casting, and in turn, lower production costs. This paper will discuss the methods used for data accumulation and analysis. In addition, three field studies conducted at three separate mining operations will be presented.

Jan 1, 1988

By Dave Proudfoot, Mike van Wyk

"There has akvays been plenty of discussion around the ‘accuracy of pyrotechnic detonators withmost recognised manufacturers claiming a variability of arourid 1% or less for their ‘superaccurate’ pyrotechnic based detonators. It is only now being understood that this 1% variabilitycan have serious adverse effects on blast performance. For example a 1% accurate 500millisecond shock tube detonator can fire anywhere between 485ms and 515ms. When wecouple these rather inaccurate ‘accurate’ detonators with short delays on surface, such as a 17millisecond connector, the probability of delay crowding and even out of sequence firing is quitehigh."

Jan 1, 1998

By John Watson

Overview: Intro and Product Use Trends ?? Packaged Explosives ?? Bulk Explosives ?? Initiation Systems – Conventional Initiation Systems – Electronic Detonators ??Q&A

Jan 1, 2006

By Z X. Zhang

In sublevel caving mines, eyebrow break usually gives rise to lower ore recovery and worse safety in the field. Eyebrow break is caused mainly by two tensile stress waves: one from the front surface of a blasting ring, and the other from the roof of the drift. In order to reduce the two waves and finally to reduce eyebrow break at Malmberget mine, we employed two methods: (1) cartridge charge, and (2) double-primers in each blasthole. The two methods were tested in one ore body called ViRi. A total of 10 rings with the cartridge charge and 25 rings with the double-primers were blasted. At the same time a total of 34 ordinary rings were blasted in the same ore body. The result shows that the eyebrow break is 3.0 m for the ordinary rings, 2.3 m for the cartridge charge rings, and 2.1 m for the double-primer rings, respectively. In addition, the ore recovery for the double-primer rings is increased by 3% on the level of ViRi930, compared with that for the ordinary rings.

Jan 1, 2011

By Bruce B. Redpath, Thomas E. Ricketts

Scaling laws commonly used for describing or predicting blast motions generated by conventional arrays of blastholes are dimensionally incorrect. The scaling of distance by the cube root of charge weight is correct only for spherical charges, and scaling by the square root of charge weight is incorrect for any charge configuration, although both approaches may result in empirically useful formulas for a limited range of charge sizes. Analysis of motions generated by a large set of underground blasts shows that scaling distance by the square root of the linear charge density, which is dimensionally correct for a cylindrical borehole, yields much more consistent results than the traditional scaling rules. Further, this scaling law is valid right up to the free face of the burden. A significant result of this work is that the peak particle velocity for an array of blastholes is primarily dependent on blasthole diameter and not on total charge weight or maximum explosive weight per delay, which are the commonly used parameters for scaling seismic amplitudes generated by conventional blasting arrays.

Jan 1, 1987

By Kurt B. Oakes, Brian M. Fortelka

Unimin Corporation operates an underground Silica Sand mine at Guion, AR located in North Central Arkansas. The Silica Sand deposit at Guion is part of the St. Peter Sandstone Formation, which is overlain by a competent dolomitic limestone from the Joachim formation, acting as the roof directly above. Both the St. Peter and the Joachirn Formations are of Middle Ordovician age.

Jan 1, 1999

By G. F. Revey

When rock blasting occurs near new concrete of varying age, engineers representing project owners often express concern that vibration from the blasting will crack nearby concrete. Regulations and/or specifications for civil construction projects usually include particle velocity vibration limits intended to protect concrete. In some cases specified limits are unreasonably low and needlessly restrict and increase the cost of excavation work. This paper discusses how methods of predicting resulting flexural strains caused by blast-motion can be used to develop safe and reasonable PPV limits to protect new concrete. Three case histories demonstrating how these evaluation techniques were used to establish higher PPV limits designed to protect concrete of various structural condition are also presented.

Jan 1, 2006

By Robert B. Hopler

The Hercudet™ non-electric delay blasting cap system has exhibited outstanding performance and economic results in surface work. The versatility inherent in the system, which allows the combining of the built-in cap delays with the tubing delay (i.e.: the travel time of the gas reaction through the tubing), has resulted in outstanding blast results. Examples of blast patterns used, details of the blast design process, and recently-developed methods of use of Hercudet for surface initiation of detonating cord downlines are given in the paper.

Jan 1, 1978

By G Dean Barrett, Ed Jr Smith, Calvin J. Konya

The purpose of the project was two fold: 1. To determine whether Pyrodex, a propellant, manufactured by the Hodgdon Powder Company, could be used as a substitute for high explosives for presplitting in granite and other materials. 2. To determine if Pyrodex, a slow reacting propellant which produces no stress waves in rock because it reacts subsonically, could cause the rock to crack similar to the results achieved with high explosives.

Jan 1, 1986

By Dieter Froelich, Giles Turcotte

In the near future, Bong Mining Company (BMC) will start mining a new deposit known as Zaweah II which is a narrow iron orebody requiring multiple row blasts with the bench floor as a free face. This called for the development of a new blasting technique. The article delineates the problem and its restrictions related to blasting. It also describes the approach which was taken for developing this new blasting technique which is essentially an application of the cratering theory with near spherical charges. Basic crater tests were conducted using various combinations of hole sizes, explosive strengths and delay patterns. From the results obtained, several alternatives were considered for production blasts and the most promising ones were evaluated.

Jan 1, 1980

By Ingvar Hansson, Bjorn A. Jonsson, Bernt Larsson

In the Kiruna Research Mine, Sweden, four large open stopes have been mined, leaving intermediate piIlars and crown pillars. At the final stage of mining mass blasting of the crown pillars above two of the stopes was carried out. The crown pillars contained some 290,000 tons of iron ore. In the mass blast a new initiation technique was used, utilizing the new non-electric system NONEL ? UNIDET. The blasting technique including vibration control is described. The mass blast resulted in high recovery, good fragmentation and low vibration levels.

Jan 1, 1986