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By Sandra K. Penttinen

A difficult blasting project can go very smoothly when every precaution is taken prior to and during the blasting procedures. These precautions include conducting careful preblast condition surveys of nearby structures, initiating a good public relations program prior to the beginning of the blasting, and following a good safety program during the blasting procedure.

Jan 1, 1994

By R J. Roach, D Roy

After months of discussion on ways and means to improve productivity in the shaft sinking process, it was decided to look at those areas where, historically, methods have been stagnant for many years. These categories included drilling, hole diameter, drill patterns, explosive types, explosive loads, initiation techniques, cut design, wall control, fragmentation and heated magazines.

Jan 1, 1997

By Rob Farnfield

The control of vibration from surface mine blasting by the application of detonator (cap) delay techniques has been universally accepted for many years. For almost as long it has been known that, for delay techniques to be effective, a minimum of 8 milliseconds delay must exist between blast holes.

Jan 1, 1999

By Tristan Worsey, Nathan Rouse, Daykin Schnell

The authors were retained by a proposed underground metals mine operation to evaluate the potential blast vibration amplitudes that could be generated at surface structures above the proposed mine. Literature reviews of published blasting documentation gave little information, data, or models on surface blast vibrations produced by underground mines. At the client’s request, the authors contacted a number of underground mining operations to evaluate interest in sharing blast vibration data with the authors so that the authors could develop an underground-to-surface blast vibration regression equation. The authors worked with three underground metals mining operations to collect surface blast vibration data produced by heading blasts and stope blasts. The data included blast vibration amplitude values, seismograph records, blast design geometry, charge weights, and detonator delay and sequence designs. The total amount of information was used to produce a regression equation and summary dataset that could be used by the proposed underground mining operation to evaluate blast vibration amplitudes that will be generated on the surface. This work is published and presented so that operations with proposed underground mines or proposed underground mine extensions can use these equations to predict vibration amplitudes on the surface above the mine workings before any blasting occurs.

By Gilberto Nunez, Ron Eastman, Hector Parra

The prediction of blasting outputs has proven to be a sound engineering tool to provide a guideline for design improvement. It has also been demonstrated to be extremely useful in critical situations when production can be compromised and there is no chance for error.

Jan 1, 2015

By Robert B. Hopler

The hazards which naturally prevail in underground coal mines, always severe and unpredictable due to the loosely-consolidated strata in which coal is frequently found, are increased by the commonly-occurring combination of coal dust, methane, and explosives. It was recognized by the mid-nineteenth century that coal dust was the basic factor contributing to disastrous explosions killing hundreds of miners, and that the ignition of methane gas was often the source of the coal dust explosions. It was apparent that preventing the ignition of methane was a critical part of avoiding these disasters, and it was also apparent that one cause of such ignitions was the firing of explosives. In addition, it was found that dust explosions were often initiated by blown-out shots of explosives in the absence of methane.

Jan 1, 1996

By C V. B Cunningham

The assessment of blasting results under production conditions is extremely difficult. As a result, it can take months or years to establish objective and valid estimates of explosive performance in achieving rockbreaking goals. This fundamental problem often results in decisions related to the manufacture, marketing, purchase and use of explosives being largely swayed by calculated energies from detonation codes. However, these codes are by no means standardised. Different energies are given by different codes because these employ varying combinations of fundamental science and empiricism. After a basic review of code operation, important guidelines to dependability are given with reference to ICI’S state-of-the-art codes IDEX and CPEX. Distinctions are drawn between Ideal, Non-Ideal and Blasting Codes. Concepts of explosive energy are discussed in brief.

Jan 1, 1991

By I. Petrovsky

Presence of the ground water, especially flowing water, causes limitations in the type of the explosives, which can be used for the blasting development in the open cats and quarries. This presents really big problem in Russia, because more than 70% of the blasting holes are wet and filled by flowing water. The waterproof explosives need to be used in these conditions, which increases the cost of the blasting development. So the search of the methods to remove the water from the blasting hole and to prevent direct contact of the explosive material with the water is important. It will give possibility to use nonwaterproof explosives (such as ANFO) and decrease the cost of the blasting development.

Jan 1, 2003

By Enrique Albarrán, Julian Hernández

"In 1942 The “Presa Mixcoac” dam was built, along with 15 other dams, to control the rain fall waterin the mountains west of Mexico City. Mexico City’s population at that time was around 1.5 millionpeople, and the dam was way out of the city."

Jan 1, 2016

By H. S. Venkatesh R. Balachander, G. C. Naveen

During the construction of a 1020 MW underground hydroelectric project in Bhutan a huge rock fall took place in the Downstream Surge Chamber (DSC) during March 2016. The total quantity of rock in the fall area is estimated to be about 1,50,000m3 (2.6 billion cubic feet), out of which about 25,000m3 (0.44 billion cubic feet) of muck was removed. The removal of muck was stopped apprehending that the cavity formed due to the rock fall may get further aggravated leading to widening and destabilising the adjacent transformer hall cavern or it might day light as the top cover was about 190m (623 feet). As the fall has virtually blocked the 314m (1030 feet) long cavern and divided it into two different chambers (south and north), and that the muck cannot be disturbed, it was decided to erect concrete wall on either side of the fall up to the cavern roof and then later address the filling of the cavity with appropriate fill material. As the access to the DSC was there for the southern side it was decided to extend a cable tunnel which was terminated at a distance on the north side of the cavern by D&B so that once it gets punctured into the north wall of the DSC it can be used to access the fall from this front too. This is a unique situation where in every blast approaching the DSC, the parting between them is diminishing and hence the tunnel blast will be exerting axial load on the parting wall leading to dynamic transient loading conditions and buckling may take place on the northern wall of DSC. This paper describes the various drill blast combinations adopted for successful excavation of this tunnel.

Jan 1, 2019

By Gungor Tuncer, Ali Kahriman

"In bench blast design, not only the technical and economical aspects, such as block size, uniformityand cost, but also the elimination of environmental problems resulting from ground vibration and airblast should be taken into consideration."

Jan 1, 1999

By Dale S. Preece

A carefully designed and controlled in-place destruction experiment was performed on a concrete bunker buried in 4.27 m (14 ft.) of soil. The objective was to determine if the explosive charges would collapse the structure in-place without requiring mechanical excavation. Collapse of the buried structure was fi rst attempted by drilling holes in the soil and placing four 13.38 Kg (29.5 lb) Comp B explosive charges at a depth of 2.13 m (6.7 ft.). The confi guration of the charges when detonated was 2.13 m (6.7 ft.) off the top of the concrete roof and 3.66 m (12 ft.) apart in a square pattern. Detonation of these charges created a crater ~4.88 m (16 ft.) in diameter and 2.13 m (6.7 ft.) deep, leaving ~2.13 m (6.7 ft.) of soil covering. Very limited spalling occurred on the ceiling of the concrete structure as a result of detonating these four charges. The second attempt to collapse the structure consisted of placing another single 13.38 Kg (29.5 lb) charge, identical to the fi rst four, near the geometrical center of the bunker roof. This charge was detonated in the soil cover 100 to 200 mm (4 to 8 in.) above the reinforced concrete roof, collapsing it. Due to the collapsed roof and remaining soil cover, the structure had been collapsed in place, requiring no further demolition. A computer simulation of the above explosive destruction scenario was completed using the computer hydrocode AUTODYN with a granular material model to treat the soil and the RHT brittle material model to represent the concrete. AUTODYN accurately recreated the scenario including the slightly damaged response of the concrete structure to the initial four charges and the collapse of the structure resulting from the second single charge close to the roof.

Jan 1, 2007

By Norman Paley

A blasting project was undertaken at the Teck Alaska Red Dog Mine in 2005 to 2007 to determine the extent that using electronic detonators could increase Semi-Autogenous Grinding (SAG) mill throughput. The results of that project were reported at the 2010 ISEE Annual Conference. This paper is a postscript to that project and provides the fragmentation resulting from the implementation of a 15% pattern expansion using electronic detonators.

Jan 1, 2012

By Liu Hui Yang Nianhua Feng Shuyu

The paper analyzed the dynamic stress in the rock around the tunnel and the effect on the stress variation for the different blasting parameters. Also, the paper verified the theoretical results by dynamic photoelastical tests and provided helpful reference for the design of blasting near a tunnel.

Jan 1, 1998

By Karl E. Burgher

Accidental explosions occur throughout the world. They can happen at chemical plants, fireworks plants, grain depots, or as a result of collisions involving volatile or hazardous chemicals. It is interesting, as we know as blasters, that we can take two very harmless products and mix them under certain conditions and produce a violent explosion. It is often very difficult for the investigator to determine the magnitudes of blasts after the fact. However, an estimate must be made to settle vibration and airblast damage claims. The blasting consultant or technical representative is often called upon to act as an expert to mitigate these claims.

Jan 1, 1993

By Luana Ferreira de Carvalho, Aurelio Manço Garcia, Gustavo Sampaio Lopes, Jose Silvio Corsini, Davi Bastos Martins de Oliveira

The Enaex Mining Technical Solutions (EMTS) team, in partnership with the Anglo American Iron Ore Brazil drilling and blasting team, has developed a study aiming to optimize the blast design applied at the Minas-Rio project. The study consists of modeling the dynamic behavior of one lithological domain to determine the best configuration of drilling pattern, charge configuration, timing and sequencing of the blast designs applied at the mine in this particular rock. The first stage of the study was the recognition of the rock blast process in question, assessing key parameters that characterize this whole operation: geomechanical characteristics of the rock mass, implementation quality for drilling pattern and explosives charging (collar position, hole depth, explosive charge length and stemming size) and recognition of current blast designs. The central element of this study was the creation of a vibration attenuation and seed wave model which has allowed the characterization of this particular rock mass present in a region determined by the Minas-Rio team. The model is based on a near field vibration test, constituting a powerful tool in the design of blast parameters. The blast design developed from the damage model simulations basically modified the timing and sequencing. The aim of this study was to improve the fragmentation resulted by the blasting, considering the particle size requirements demanded by the primary crusher and to increase the productivity of the loading and hauling operations. The results were analyzed considering the effective productivity of the two different fleet types of shovels, where the authors have analyzed more than 46000 values of productivity from September 2017 to August 2018, taken from the Dispatch system. A significant increase in effective productivity of these load equipment was observed, 7% to the PC4000 fleet and 2% to the PC5500 fleet, values supported by statistical parameters and hypothesis tests.

By T Goswami

The conventional practice in open cut coal strip mining has been to blast the overburden or coal layers in separate blast events. This is done in order to maximise the benefits from throw blasting and also to limit coal losses. Each blast event usually has a particular design of hole diameters, burdens and spacings, explosive charges and blast timing in order to achieve the required blast outcome for either the overburden or coal. This means that each blast has to be separately cleaned on the surface after excavation of the previous blast. Hole locations then have to be individually surveyed and marked, holes drilled, explosives and initiators loaded and the blast fired. Each of these actions takes considerable time and resources and therefore impacts on mine productivity. The mine has to be cleared for each blast event and every blast presents a new potential source for noise, dust or vibration disturbance to the neighbouring population. Exposed highwalls are also subjected to vibration and damage from each subsequent blast event

Jan 1, 2006

By David Porter, Nathan Rouse

The implementation of presplit blasting has been widely utilized in open pit and underground tunneling. This case study works through the iterative process of developing a heading drill and blast design to control overbreak and limit backbreak in cut and fill headings. The initial design was based on rule of thumb parameters, and the design was then modified for the field conditions based on results. Throughout the design process the drill profile, explosive charge, and timing were modified to yield the best profile compared to design. Data collection during the design process was extensive to best understand the effect of modifying parameters, and gauge performance of design changes. Input from the miners as well as engineers was considered to allow for the best possible adaptation of the design change from existing practices. During the process resistance to change was realized and accounted for to understand the issues that the miners were facing and how to best address them while ensuring high quality blasting. Workforce buy- in was addressed by illustrating the long term benefits of higher quality blasting and the tradeoff of with a slightly more in depth drill and loading cycle.

Feb 6, 2023

By Xue Yongpeng, Zhu Zhenhai, Zhu Ming

The purpose of the Solid Medium Controlled Blasting Technique and Its Applications is to have the inside of the vessel-shaped framework (e.g: oil tank , water pool, gas chamber, chimney, water tower, grain warehouse and etc.) or the one side of the thin wall-shaped structure(e.g: steel bar concrete wall and etc.), both of which are intended to be demolished, inserted with the required solid medium (e.g: soil , sand , coal, salt and etc.) ,in which there is a certain mass density, and then through which the blasting energy is transferred to fulfill the blasting task. For such a technique, it is necessary to bury the explosives into the inserted solid medium and then to start the explosion to blast the intended target into pieces. The filling of the solid medium may be done mechanically or by man. Compared with the water pressure blasting technique, this one has the characteristics of good effect. wide application, simplified construction procedure , safe and reliable operation and small vibration (less vibration than water pressure blasting by 80% to 90%)in particular without any flying stones, thus resulting in better and comprehensive social and economickfficiency.

Jan 1, 2000

BLASPA is the name for a computer code which can assist in the rapid optimisation of blasting procedures in an open-pit mine. BLASPA is based on a mathematical model of the blasting process, a model which has been developing since 1963 as a result of blasting research carried out at the College Militaire Royal de Saint-Jean under sponsorship of the Defence Research Board, and in co-operation with the mining and explosives industry. The model presently includes the following aspects: (1) Geometry, i.e. spacing, burden, bench height, collar, sub-grade drilling; (2) Explosives, i.e. types and grades of explosives, distribution into bottom and top load or decking, size of hole and coupling; (3) Hookup, i.e. parallel or angled firing, delays, location of primers. Computer costs are very small, by comparison with purely spherical AEC codes, so that any number of simulations can be carried out very efficiently. The system has already been used to carry out thousands of simulations for over 40 mines in Canada and abroad. It will be explained how such simulations become a useful guide for a mine's blasting engineer who wishes to optimize his blasting and drilling costs.

Jan 1, 1980