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By S B. Richardson, R E. Danell, D Mead, N T. Moxon

Explosives provide a very concentrated source of energy which is often well in excess of that required to adequately fragment the surrounding material. Blast design, environmental requirements, production requirements and the lack of detailed insitu geological data generally limits the degree to which the explosive energy distribution within the blasthole can be significantly altered using, for example, different explosive formulations or variable loading techniques. However, increased flexibility can often be exercised over a blast through the use of air-decks.

Jan 1, 1993

By Jerry Wallace

Construction of a new grammar school required blasting within three meters of the existing school. Due to changes not anticipated at time of bid opening, blasting had to take place while approximately 200 children were in attendance inside the building. Blasting with children in such close proximity forced the blaster to review and revise a systematic approach to construction blasting and make changes to previous Rules of Thumb guidelines. The revised rules of thumb place Blaster-in-Charge at the top of the List. Other changes specific to the project included putting in place a blasting safety plan that included communicating the serious job hazards to teachers and students. The plan included stringent lockdown guidelines establishing school procedures for accounting for each student prior to the countdown-to-blast being implemented. Emergency communications channels were kept open so that any scheduled blast could be aborted at the last instance.

Jan 1, 2001

By Yves Lizotte, Malcom Scoble, Pierre Michaud

The concept of optimum fragmentation in surface mining operations, i.e. the degree of fragmentation to which corresponds the lowest overall associated costs of drilling, blasting, loading, haulage and crushing, was developed more than thirty years ago. Recent field investigations using novel technologies, which have been completed by ICI Explosives Canada and by others, indicate that this ultimate goal of optimum fragmentation is closer to becoming reality.

Jan 1, 1997

By James A. McGrath

"The predominant key word associated with all commercial blasting methods is “safety”. Safetyshould take precedent over all other aspects of the entire explosives industry which on a wholehas had an excellent track record as to number of injuries per unit of hours worked at all blastsites throughout our country."

Jan 1, 1999

By Ali Kahriman, Olivio Angelini, Ibrahim Sefer, Burak Ekmen, Koray Arpak, Ertugrul Kaya, Yucel Karakus, Abdullah Sak, Aziz Ozdemir

In recent years, in order to bring solution to traffic intensity arising from transportation problems and facilitate public transportation in the modern world in paralel to urbanization and to the increase in population, it’s well known that, the construction of Access tunnels is inevitable. The driving of the tunnels is a subject of special interest in the technique of rock blasting. The essential factors in terms of tunnel driving and safety in tunnel blasting that is applied in metropolitan areas, an in depth knowledge of ground vibrations and the ways of reducing them to safer levels.

Jan 1, 2010

By Joseph Meyers

Explosives techniques and technology are constantly evolving and improving, yet basic communication and business skills are not being used regularly. Many potential blasting projects never occur due to simplistic, basic factors, such as a lack of communication. Articulate communication is the key component in the blast approval process, which has changed remarkably from how business was conducted fifty years ago. Imperative to the approval process is communication outlining the safety and benefits of the blasting project. Information and transparency with the stakeholders and the Authority Having Jurisdiction (AHJ) will greatly improve the chances of having a blasting project approved. This open communication starts at the inception of the project when the memorandum of understanding (MOU) is obtained, and involves the AHJ through all steps of the approval process. The blasting industry and regulators must work collaboratively to improve safety, security, regulations and licensing. Implementing state of the art blasting techniques, security, safety measures, vibration monitoring and strict licensing allows the AHJ and all stakeholders to remain integrated and informed, contributing to process approval. Regulatory operators should strive to achieve success thru communication, cooperation and compliance which is accomplished thru continued education and transparency. These steps, combined with regular meetings, has proven to be a benefit to both industry and regulators. Relationships are built through trust, teamwork, transparency and communication –including the take holders and AHJ in the approval process from the inception solidifies these relationships and improves teamwork

By Ali Kahriman, Abdulkadir Karadogan, Umit Ozer, Mehmet Aksoy, Deniz Adiguzel

The environmental problems arising from ground vibration has been faced and discussed frequently in various industries such as quarry, mining, civil works, shaft, tunneling, pipe line and dam construction etc. where the blasting operations are unavoidable. In bench blast design, not only the technical and economical aspects, such as block size, uniformity and cost, but also the elimination of environmental problems resulting from ground vibration and air blast should be taken into consideration. The prediction of ground vibration components plays an important role in the minimization of the environmental complaints. This paper presents the results of ground vibration measurements carried out in the quarries located on the different sides of Çatalca district in Turkey. In order to predict peak particle velocity level for this district, ground vibration components were measured for shots during bench blasting at these quarries. In blasting operations; ANFO is commonly used as blasting agent at the quarries. The type of priming and firing differed from quarry to quarry. The parameters of scaled distance (charge quantity per delay and the distance between the source and the station) were recorded carefully and the ground vibration components were measured for all blast events by using different type vibration monitors. The absolute distances between shot points and monitor stations were determined by using GPS. The equation of square root scaled distance extensively used in the literature was taken into consideration for the prediction of peak particle velocity. In order to predict, and compare the influence grades to the neighboring buildings, and structures at the Çatalca district, the particle velocities and frequency values of all blast events are evaluated according to the United States Bureau of Mines (USBM) and German DIN 4150 Norms due to the lack of a national standard in Turkey. Then, the data pairs belonging to these quarries were gathered together to represent the district and were analyzed statistically. At the end of statistical evaluation of the data pairs, an empirical relation which gives average line at 95% confidence level and upper bound 95% prediction line with a reasonable correlation coefficient was established between peak particle velocity and scaled distance

Jan 1, 2007

By Satish Kate

Mining of Iron Ore in India is done by Surface Mining methods and most of the deposits are massive and are occurring in Hills, surrounded by green forest cover. While majority of iron ore produced are from mechanized mining systems, some quantities are also produced from semimechanised mines. In mechanized mines, apart from state-of-the-art level of mechanization, the Run-off-Mine ore is subjected to multi-stage crushing, screening and washing/beneficiation, for improving the grade and ensure segregating of different size range. The steel plants within the country have been operating their own captive mines, where both lumps and fines are used in their furnaces. In case of mines, which exclusively supply ores to export market, the lumps produced yield very high price and thus efforts are being made to maximize lumps recovery. The mine, where the author had been associated, is an export-oriented mine which supplies iron-ore to Japanese steel plants.

Jan 1, 2004

By Dale Preece, Ayman Tawadrous

This paper presents a number of examples of three-dimensional blast modeling in both surface and underground environments that include time-delay explosive decking. These examples include: 1) quarry blasting, 2) coal seam protection blasting, 3) mineral mine blasting with high energy time delayed decks, and, 4) underground single-level/single-shot drawbell blasting.

Jan 1, 2014

By Chulgi Suk, Hoon Park, Hyonsoo Kim, Hakman Kim, Sangho Cho

Dust emission from blast demolition and other construction activities can be a nuisance; it is widely recognized that fine particles less than 10 µm in equivalent diameter (called PM10) may cause health problems. Mist spray systems, such as rain guns, sprinklers, water/surfactant sprays (or foams) etc., are some of the most effective dust suppression methods. A large amount of research has showed that when water droplets are produced in an equal amount to that of dust particles, the airborne dust is suppressed by the agglomeration of dust and mist particles. A method for generating micro-sized mist from water, achieved by the detonation of explosives in the water tube, was suggested and is called the ‘detonationdriven water bag burst system’. There are many experimentally observed limitations of the explosioninduced water break-up process. The water bag explosion tests were simulated using the AUTODYN software, in order to investigate the aerosolization mechanisms of the detonation-driven water and water break-up process into micron-sized droplets. As a result of the numerical analyses, the diffusion direction of water when detonating in the central interior part of water tube was radioactive and significantly stronger than when detonating in the bottom exterior part; this is due to the compressive flow of the volume change inside of the water tube, which resulted from the blasting wave inside of the tube, as well as the reflected pressure on the ground. Blast tests of full-scaled reinforced concrete columns were conducted to verify the effectiveness of the suggested detonation-driven water bag burst system. The water breakdown and dispersion that occurred while blasting the reinforced concrete columns were observed using a high-speed camera, and dust generation was monitored using four density detectors. The suggested detonation-driven water bag burst system showed that the average dust density decreased by up to 7 mg/m3.

Jan 1, 2016

By Roberto Folchi, Hans Wallin

Lake Mead, the largest man-made reservoir in the United States, is located about 30 miles southeast of Las Vegas, Nevada. For the construction of Lake Mead third water intake, which is entirely placed underground, an underwater excavation was needed at a depth of 100 m (330 ft): a large surface had to be deepened by 20 m (66 ft) in basalt.

Jan 1, 2012

By Charles Barnhart

This paper is a discussion of the causes of deflagration in cast blasting and a description of a project intended to demonstrate how changes in six critical parameters contribute to the deflagration chemical reaction. Control of these parameters is key to solving the nitrogen dioxide “orange smoke” problem. Preliminary results of an investigation into the development of a technology addressing the problem of atmospheric releases of nitrogen dioxide during cast blasting in surface mine operations are described. The project is funded by a $600,000 Small Business Innovative Research grant from the National Science Foundation and an $80,000 Abandoned Coal Mine Land Reclamation Program grant from the state of Wyoming. The presentation will address the measures required to control the blast chemical reaction so that it does not produce nitrogen dioxide through deflagration. Experimental blast data will be focused on a new shaped charge detonation system designed to instantaneously bring the powder column to maximum velocity of detonation (VOD), thus insuring efficient detonation of the entire colulnn.

Jan 1, 2003

By Kameron Ray, Ruilin Yang

This paper compares the modeling results obtained by using a single seed waveform (SS) versus multiple seed waveforms (MS) as inputs to the Multiple Seed Waveform (MSW) blast vibration model. The field data for the comparison was collected at a coal mine. The results of the comparison showed that the MSW model yields more accurate predictions and significantly higher correlation to field measurement when using MS as input. When using a single seed waveform as input, different seed waves result in different predictions of PPV. In contrast, using the multiple seed waveforms as an input, more consistent results are obtained.

Jan 1, 2013

By Michael Weaver, Dale L. Ramsey

The Pinkerton Tunnel open cut project is part of the National Gateway Clearance Initiative improvement project to achieve a minimum of 21 feet of vertical clearance along CSX Transportation rail corridor so that double-stacked intermodal railcars can be transported between mid-Atlantic states and their ports to midwest markets in the U.S. This project involved drilling and blasting of 1.2 million bank cubic yards of rock over a 14 month period while maintaining rail traffic of two passenger and 38 freight trains daily. See story and photos, page 6.

Jan 1, 2015

By Ken Schei, Martin Reed, Samuel Bowser, John Wright

From October 18 through October 21, 2001, United States Antarctic Program blasters opened ten access holes for research divers in 11-ft. thick sea ice at Explorers Cove, McMurdo Sound, Antarctica. During this project, a blasting seismograph with a hydrophone accessory was used to monitor the underwater shock waves associated with the blasting technique. Shock wave values averaged 42.3 psi for initial (cratering) shots and 5.9 for subsequent clearing shots, indicating that the ice absorbs most of the shock wave. The results also provide data for refining safety protocols for divers and for the protection of marine biota.

Jan 1, 2003

By C F. Argo

In the past several years the "Kelly Bar", an innovative device, which incorporates borehole d-rifling and explosives loading into a single detail, has come under scrutiny and criticism. The practical aspects of the Kelly Bar procedure is not questioned, and the system has been highly successful in expediting the loading of explosives in difficult and unstable formations. There have been a number of accidents indirectly associated with Kelly Bar loading and the point in question has become one of safety rather than mechanical feasibility.

Jan 1, 1975

By M. Ramulu, A. Raina, A. Chakraborty, Jethwa Choudhury, Dudhankar

Application of digital image analysis technique for assessment of blast fragmentation is gaining grounds in India, very recently. Central Mining Research Institute, India made its maiden attempt to optimize blast design based on fragmentation assessment of one of the biggest opencast mines of Singareni Collieries Company Limited, India. Indigenously developed photoanalysis software called ‘FRAGALYST’ was used for measurement of blast fragmentation A series of trial blasts were carried out in overburden benches with ongoing blast parameters and pictures of muck pile were taken by video camera for image analysis. Cycle time study of loaders and dumpers was done to determine machinery performance for each and every blast. Optimization of pre-blast parameters like specific charge, specific drilling and post-blast results like shovel cycle time and dumper cycle time, was done to determine optimum range of fragmentation. Interpreting the mean fragment size (K50) obtained by image analysis the blast design parameters were modified.

Jan 1, 2001

By Rundqvist

The best method to minimise disturbances from traffic to the neighbourhood and in Urban is probably to go underground. For obvious reasons this will cause vibrations, noise and other environmental effects which need very strict regulations and quality assurance in order to complete the work successfully. One project is “Southern Link”, a part of a ring road system. The system of tunnels includes 16 kilometres of tunnels right beneath the south part of the city of Stockholm. At least 20.000 people will be or could be affected by different kinds of disturbances and pollution such as vibrations, noise, gas and groundwater. Another project is the “Arlanda Link”. A new railway with three stations has been built under the existing and running to Arlanda airport with its terminals. Authorities have carefully judged these projects, which cause complaints from neighbours due to disturbances. The blasting operations are professionally managed by the contractors and controlled by consultants to keep the regulations according to the Swedish standards, which are well described in the tender documents by risk analysis and technical descriptions. In spite of that, one conclusion is that it is not always possible to go underground without exceeding stipulated regulations with existing technique. Some of the regulations also double the cost of excavation

Jan 1, 2001

By Doug Anderson

Blast vibration seismograms are generally collected strictly for compliance with regulations. The peak levels (including dominant frequency) are typically all that are looked at. However, these records contain a lot more information about how a blast has performed. The seismogram is actually a record of explosive energy that was not used in fragmenting rock. The trick is to determine how to extract information that would be useful in analyzing blast performance.

Jan 1, 2013

By Leslie Taylor, W. L. Fourney, Uli Leiste

Over the past few years, our laboratory has been investigating the loading on vehicles due to the detonation of buried explosives. We have been using target plates to represent the bottom of the vehicles that were being subject to the forces from the detonating explosives. Parameters shown to be important in the blast loading were type of soil, stand off distance (distance from the surface of the soil to the bottom of the target plate), and depth of burial (distance of the charge center of gravity to the sand surface). We conducted over the first year of our work a large number of tests which looked at the impulse being applied to the plates as a function of depth of burial, stand off distance, and type of soil. Of the three parameters we found stand off distance to be most important, depth of burial to be the next most important parameter, with type of soil least important. We also found that impulse could be scaled with explosive size quite accurately and that results (for impulse) were quite repeatable from one test to the next.

Jan 1, 2008