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By C Deacon, M Jones, P Duniam

Electronic blast timing has been in use around the world since the mid-eighties, and, whilst it has yet to be used commercially by large operations on an ongoing basis, significant inroads have been made in niche areas where tighter control of blasting is required.

Jan 1, 1997

By Deane Tunaley, Clint Brearley, Steven Kotsonis, Richard Goodridge, Tom Smylie

Explosives are widely used in the Oil & Gas Industry for subsurface mapping via measurement of reflected sound waves as each charge is detonated. To complete a seismic survey, several thousand explosive charges may be deployed into narrow boreholes, often in areas difficult to access or where socio-political factors may increase the risk of unlawful recovery or sabotage of the explosives. Therefore, when misfires occur, the explosives left in the ground often cannot be retrieved or sympathetically detonated safely, in which case they are “abandoned” (in-line with local regulations) potentially posing a safety and security risk.

Jan 1, 2014

By S R. "Bob" Pilshaw

Productivity is the popular "buzz" word that catches the attention of most managers when it is featured in the more popular mining and construction magazines. Engineering Task Forces and teams are formed to take advantage of productivity opportunities in almost all phases of an operation except the drilling and blasting area.

Jan 1, 1988

By Wang Hao

"Demolition of reinforced concrete frame structures in building crowded cities is a hardproblem in control blasting. Any mistakes, e.g. wrong toppling direction of multi-storeybuilding or incompleted blasting of structures will all cause terrible accidents.To demolishframe structures safely, various disciplines including structural mechanics, explosionmechanics, rock engineering, etc. are involved"

Jan 1, 1993

By Miles Huntly

This paper will discuss the ideas and actions that led to the development of a Drill Improvement Team at an open cut coal mine in Australia. It will show significant cost savings can be attained by forming a focused Team derived from all the participants that go into drilling a blast hole

Jan 1, 1999

By Cary Moffat, John Kita, Rick Walker

The Lac des Iles Mine, in an isolated area of NorthwesternOntario is a relatively new open pit platinum and palladium mine. They were encountering problems with the equipment and production scheduling when ramping down to begin production on the subsequent benches. A co-operative effort between Lac des Iles Mine operation people, ICI Explosives, and the mines drilling and blasting contractor - Consbec Inc., resulted in a decision being made to use full depth sinking cuts to provide access to the next bench.

Jan 1, 1996

By Peter Moser, Mark Ganster, Andreas Gaich

Surveying of a bench face before blasting is a pre-requisite for a proper blast planning and for a satisfying blasting result both in terms of safety and fragmentation. When surveying a bench face, preferably a large amount of measurement points are required in order to determine the geometry and especially the irregularities with sufficient accuracy. Only contact-free measuring systems allow evenly distributed measurements over the whole bench surface. Existing systems such as total station, laser profiler, or laser scanner show significant drawbacks such as that surveying results are just isolated values of the bench geometry such as heights or profiles, that borehole positions have to be defined in advance in order to know where to take profile measurements and that systems require special surveying skills and that they are expensive too. In order to overcome these difficulties and to provide the blasters a simple tool for bench surveying, blast design and layout and the subsequent back-transfer of the blast plan into the quarry, the Department of Mineral Resources& Petroleum Engineering of the University of Leoben, 3G Software & Measurement company and Mineral AB, one of the largest producers of aggregates in Europe formed a joint venture to develop a new system. Based on an existing stereophotogrammetric system for rock surface surveying and joint analysis (JointMetrix), a new tool was developed within a year. Apart from several mines and quarries using that new tool already today in the daily work, both the Department of Mineral Resources& Petroleum Engineering at the University of Leoben and Austin Powder GmbH Blasting Service did a lot of studies to determine the reliability of the new stereophotogrammetric blast surveying and planning system and its precision in comparison to classical laser surveying equipment. After 1 year of testing and comparison with laser based surveying instruments, it can be concluded, that the new technology of blast surveying& design systems based on stereophotogrammetry is suitable for being used in the daily work routine in quarries and mines. The comparison of the precision of laser based systems and stereophotogrammetric systems has shown, that the deviation between these two types of systems is less than 10 cm, in many cases even lower.

Jan 1, 2007

By Peter Reinders, Dirk Hummel

This paper describes a new digital Centralized Blasting System (CBS), which is currently being introduced into underground applications. The CBS makes use of the field-proven detonator and equipment technology of an electronic detonator system and existing mine radio communication networks. Therefore no capital investment for additional mine infrastructure networks is required for the deployment of the digital CBS. Components of the new system are a Remote Blasting Box for use at the actual blast site and a Master control unit ‘Lockbox’ which is located at the central blasting location of the mine. The system is operated via a PC based centralized blasting software. Several sophisticated safety devices guarantee the highest safety standards are maintained with the application of the new digital CBS.

Jan 1, 2004

By C. McAllister, D. Preece, J. Berendzen

The Multiple Blasthole Fragmentation (MBF) model was developed recently and has been reported in previous papers. The MBF model accepts inputs from the blast design, such as: location and orientation of each blast hole, stemming length, blast hole diameter, multiple decking, bench height, initiation sequence, etc. It models the effect on fragmentation of delay timing with its associated scatter for each blast hole. MBF has a statistical modeling capability for geological random variation of the attenuation of particle velocities. Also simulated is wave reinforcement due to the interaction of simultaneously arriving waves or diminishing cooperative contribution from long delay intervals between charges.

Jan 1, 2016

By Stuart Brashear, Eddie Colburn

The Birmingham Coal and Coke – Knight Mine is a single seam coal mine in central Alabama. As pit development progressed in 2013, concerns over increasing vibration levels resulted in modifications to the blasting program that inhibited shot size and coal recovery. By January 2014, while still over 1,400 feet (427 m) from the regulatory seismograph, vibration levels climbed above 70% of the mine permit limit, even with triple decking of holes and reduced burden and spacing. At this time the decision was made to commit to the use of signature waveform analysis and precision programmable electronic detonators to minimize vibration and maximize the amount of coal that could be recovered before vibration levels reached permit limits.

Jan 1, 2015

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 Mark Svinkin

The purpose of this paper is to present an overview of recommended existing criteria of ground vibrations generated by blasting. It is shown that these criteria have limited liability because they were found for specific categories of structures. A new approach based on measurement of structure vibrations is suggested for assessment of damage in structures subjected to blasting vibrations. This approach provides the flexibility of implicitly considering a variety of soil-structure interaction and structure conditions. It is explained a new frequency-independent safe-level criterion of 51 mm/s (2 in/s) for the PPV of structural vibrations. Attention is brought to use seismographs properly calibrated for the required frequency range. Positive flexibility is demonstrated in assessment of structure and component of concern vibrations from blasting.

Jan 1, 2003

By D P. Yang, Yang R. G

The laws of throwing and heaping of engineering blast are important for making use of throwing and heaping of thrown body to form certain shape, such as building dams by directional blast. The article is to apply Ballistic theory of single thrown body to take the throwing course of thrown body as the movement of particle system, and then delimit the total of thrown body into units of thrown bodies, and regard the heaping shape of single thrown body as a perfect triangle, and found a quantitative relation between macro-geometry parameters of perfect triangle and designed parameters of explosives. The theory has been adopted in blast practice and gotten good effects.

Jan 1, 1999

By James Rowland, Richard Mainiero

When most people think of explosives transport they think of a hazardous operation. We all know that we aren’t allowed to transport explosives through tunnels and are discouraged from traveling through heavily populated areas. Popular opinion suggests that explosives transport is a very risky operation. The authors decided to look into this a little more thoroughly and found just the opposite to be true.

Jan 1, 2008

By Minoru Kawamura, Shinya Tanaka

In Japan, a cartridged emulsion explosive is generally used for tunneling. The workers are compelled to approach the face on charging the explosives into the drill hole with the tamping rod. Therefore, the workers are exposed to the risk of the disaster with the cave-in and the falling rock. The mechanization of the tunnel work has been advancing gradually. Especially, the development of the mechanization for charging work is desired in order to avoid the risk of disaster on workers. Recently, some charging machines such as the bulk emulsion explosives have been evaluated. However, a universal method has not been established yet, because the evaluated machines were not adequately suited from the point of the regulations and the consumption style of explosives.

Jan 1, 2008

By Huang Fenglei, Jin Qiankun

A new linear charge method has been applied in coyote blasting for highway excavation in which presplitting boreholes are set along the designed rock slope with some empty chambers at the end of linear charges whose axes are perpendicular to the axis of the highway. Three-dimensional nonlinear finite element analysis for this method has been conducted using LS-DYNA3D. The results indicate that the blasting damage to the rock slope is reduced greatly using the new linear charge method in coyote blasting.

Jan 1, 1998

By Alastair Grogan, Ron Elliott, Dale MacLean

Blasting for armour stone presents many unique challenges. Often, blasters get themselves into trouble when they assume that they can simply modify a production blast design to produce the required fragmentation size. They bid on the project using typical production blasting costs, and then find that they cannot produce the required fragmentation size and quantity with an acceptable waste factor. This paper outlines industry best practice guidelines for the production of riprap or armour stone. The paper examines the importance of initial geological mapping to determine the average in-situ block size, and the advantages to be gained from working with the geology to maximize production of the required block sizes. The paper also outlines the importance of proper explosives selection as well as blast designs that are unique to the production of riprap. The paper reviews challenges and experiences realized from multiple projects in differing rock types.

By S. S. Jenkins Jr.

While the method is seldom used anymore, coyote blasting is an historically interesting way to blast large quantities of rock. It was used extensively in the days before modern fast drills were available and can be very effective in some formations that have a natural breakage pattern. This paper will cover the general principles, some blast design factors and point out several actual blasts including some very large ones.

Jan 1, 2005

By Michael Allen, Paul Worsey

In underground blasting, the pull of the initial cut is the limiting factor for the success of the rest of the round. By improving the pull of the first cut, a critical step is made towards improving the entire round. This project attempted to optimize a burn cut’s effective pull by varying the depths of the relief holes in the burn. The effect of varying the depths of the relief holes was investigated, including depths longer than that of the cut’s charged holes. The overall objective was to consistently achieve greater pull than in a standard burn, using an identical amount of explosives. Increased pull results in savings of both time and cost in underground heading advance.

Jan 1, 2015

By H J. MacDonald

An Exploding Bridgewire Detonator (EBW) is an explosive initiator which contains only secondary explosives such as PETN and RDX. It is safer than the normal blasting cap because it requires both high electrical energy and a very fast application of that energy to function

Jan 1, 1981