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Explosives and Blasting Technique, Holmberg (ed.) © 2003 Swets & Zeitlinger, Lisse, ISBN 90 5809 605 X
Electronic blasting and blast management F. Hammelmann Technical Service – Field Support, Orica Germany GmbH
P. Reinders R&D Electronic Blasting Systems, Orica Germany GmbH
ABSTRACT: Since blasting was introduced in mining as part of the production process, blasting technology and blast management have been interconnected. Over the past decades Orica Explosives has gained experience with electronic blasting systems in mining, quarrying and construction. In the beginning the primary focus of electronic blasting was to increase the timing accuracy. Over time the technology gradually developed and opened up new possibilities such as flexibility in blast design and full function verification. Furthermore, modern electronic blasting systems are designed to allow easy two-way transfer of information between the office based blast management software suite and field equipment. Blast management systems comprise a suite of expert systems for planning, documentation, analysis, measurement and prediction of blasts. The blast design software SHOTPlus®-i is an integral part of Orica’s blast management suite, which allows to transfer blast design information to the hardware of the electronic blasting system. This paper briefly describes the history of blast management. In the following a modern blast management suite is presented, which provides a link between the electronic blasting system and the blast design software. Finally an outlook gives an impression of tomorrows integrated blast management systems.
1 BLAST MANAGEMENT IN CHANGE OF TIME In the 12th century the use and manufacture of black powder was developed in China. But it took more then 200 years, before black powder was introduced in blasting for civil purposes in Europe by Bertold Schwartz. The first civil blast in an underground ore operation – documented by Casper Weindel – took place in the German “Harz” mountains in 1627 (Petzold et al. 2000a).
Figure 1. First documented blast in underground mining.
Since mining activities always have been – and still are – a time and cost intensive business, accurate planning and engineering have been important form the very beginning of civil blasting. Blasting technology as part of the production process and the evaluation of blast performance has therefore been a key interest of mine operators to improve cost efficiency of the operations. The first blast management tools were developed to evaluate the basic geometric parameters of benches or stopes before and after blasting. Drilling and blasting parameters were controlled by the use of “plumb and scale”, a method which is still commonly found in surface production blasts nowadays. The capability to measure geometric parameters was the basis for an improved engineering and blast management. The first measuring technologies made use of gravity, position of sun and stars and the magnetic field of the earth. The next generation of optical tools was developed to enable engineers to measure distances (e.g. burden and spacing). These new tools allowed to transfer a reference scale to any place in the blast site. The next important step was the development of precision tools for measuring distances and angles and the ability to
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Figure 4. Orica’s standard blast management suite for an electronic blasting system. Figure 2. Early days of blast management.
Figure 3. Optical tool for trigonometrical measurements.
calculate other distances and angles on basis of the measurement results. Today sophisticated measuring tools – based on different measuring principles (magnetic-field, optical scale, gravity, laser profiling, etc.) – and dedicated software programs are available for planning and control in mining industry. 2 ELECTRONIC BLASTING AND BLAST MANAGEMENT The standard software tools in a blast management suite are programs for fragmentation analysis, for blast performance prediction and for initiation design. The later can also be part of the prediction software. A variety of such programs all with different capabilities are available in the market. These programs can be considered as the standard tools in a blast management suite. Furthermore such a suite may comprise different programs for surveying, cost calculations, equipment planning, vibration modelling or for distinct modelling
of muckpile displacements, etc.. The different software tools typically require dedicated databases, even though the input parameters are in many cases essentially the same. The missing common platform for the software tools makes the mine planning process very complicated, duplicating work at many stages of the product cycle. In top only highly skilled specialists can apply the software tools. Figure 4 shows the standard programs (PowerSieve®, Sabrex, SHOTPlus®-i) of Orica’s blast management suite and the interconnection to the electronic initiation system i-konTM. After blasting the fragmentation analysis results can be used for a calibration of the prediction model. Input parameters are type of explosives, initiation system, the rock mechanical characteristics of the ground, hole length and diameter, burden and spacing, the delay timing, etc. Over the time and with continuous calibration of the prediction model the quality of the prediction – like fragmentation, heave, shape of wall – becomes more realistic. The results of the prediction model can then be used for optimising the blast design of the electronic blasting system. The input parameters of Orica’s standard tools share the same data bases, so that the time and work required for carrying out an analysis is minimised. The blast design software SHOTPlus®-i provides the link to the digital blasting system i-kon™. SHOTPlus®-i has been specifically designed for use with the hardware components of the electronic blasting system. These are: the digital detonator, the Logger for logging, testing and programming the detonators and the Blaster for firing the detonators (Petzold et al. 2000b). SHOTPlus®-i provides a simple and convenient way to design a blast, to carry out some basic design analysis and to create pre- and post-blast reports. The software is available in two different versions: SHOTPlus®-i surface, for use in surface applications and SHOTPlus®-i underground, for use in underground applications.
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Figure 7. Blast design on basis of mine data. Figure 5. Hardware of the i-kon™ Digital Energy Control System.
Figure 6. SHOTPlus®-i Surface: application interface and visualisation of blast sequence.
The application interface in the surface version consists of a top line main menu, a series of tool buttons on the left hand panel and a bottom status line. The button tools are grouped according to their functions:
• • • • • •
Viewing Drawing Measuring distances Blast design (explosives, primers, stemming, hole length, diameter, angle, pattern, numbering or names, harness wire) i-kon detonator delay time design Logging sequence.
The resulting blast design is shown in plan view, but does contain X,Y and Z coordinate information. The software also allows to import text file data in either the standard DXF (AutoCAD) format or from a file formatted with columns of data. Apart from the pattern and hole information this includes also the mine specific numbering/names of the holes. Figure 7 shows an example of a blast design on basis of an import of mine data.
Figure 8. Design parameters for a single blast hole.
Each blast hole in the design can be edited to show the specific design parameters. The main menu contains standard menu items found in most applications for managing files. Furthermore the software contains a Quick menu for the common actions, a View menu for managing the information currently displayed, a Calculations menu for evaluating the blast design and a Tools menu for selecting less common tasks. The calculations menu allows simple initiation calculations to be performed on the blast design. Entering a calculation mode will display the results within the edit window:
• • • •
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The visualise command shows a representation of the firing sequence of the detonators at different display speeds (Figs. 6, 9). The first movement displays a representation of the direction of first movement of material based on the hole firing times. The burden relief gives the amount of time delay per metre of burden across the blast. The angle of initiation shows the timing contours.
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To allow for the required flexibility on the bench, the Logger enables to add detonators or holes that were not considered in the design, or to leave out designed detonators or blast holes, in case detonators are missing or holes are not drilled. The required time for logging of the detonators is considerably reduced, because the delay time must not be entered manually at the hole. The logging process only serves to register the unique names of the detonators, when SHOTPlus®-i is used. As a result the operation speed is comparable to a tie up with non electric detonators. 3 BLAST MANAGEMENT SUITE OF THE FUTURE Figure 9. SHOTPlus®-i underground: application interface and visualisation of blast sequence.
Figure 10. Download and upload of data to electronic blast equipment.
• • •
The time envelope shows the hole deck firing times and allows to check the amount of explosives per delay time. The quantities calculation displays the number of detonators, the amount of harness wire, and the amount of explosives consumed in the blast. Logger data enables the download of the design to the equipment and the post-blast upload to the design file.
The underground version allows planning and viewing a blast design in three dimensions. The application interface with the available menus and tools is essentially the same as in the surface version. After a blast has been designed, the design information for the electronic blasting system, like the name of the row, hole numbers and detonator delay times in the holes is downloaded into the Logger. On the bench or underground the detonators must be logged in the designed sequence with the Logger.
Today’s blast management suites are typically missing a common platform that allows an easy transfer of input and output parameters to other tools of the suite of programs. As a result the work involved during blast management is often more time consuming then necessary and the planning process inefficient. However, Orica has addressed these limitations and is currently building an integrative blast management suite, which increases the efficiency of the blast management process. If the overall planning process of a product life cycle in a mine is considered, the same problems are encountered. Many different expert tools require different databases. In many cases this implies that the work involved during the planning process is duplicated and becomes more complicated then necessary. An easy way for a transfer of analysis results from one step in the planning process to the subsequent step is often not possible. In the future all the information and the whole engineering during the planning process will be covered by an integrative mining software suite that shares the same data platform. The output of the first expert tool used in the mine planning process can then be used as an input for the next tool in the planning process. All the different data bases (geological and rock mechanical characteristics of mineral and ground, explosives, mining equipment, cost calculations, …) could be used from a common platform, which supports the whole planning process. This would significantly improve the overall efficiency of the planning process.
REFERENCES Petzold, J. & Hammelmann, F. 2000a. Zündtechnik im Wandel der Zeit. Nobelhefte. Heft 2000: 1–17. Petzold, J. & Hammelmann, F. 2000b. The second generation of electronic blasting systems. In Holmberg, R. (ed), Proceedings of the 1st World Conference on Explosive & Blasting Technique, Munich, Germany, Sept.6–8, 2000: 159–164. Rotterdam: Balkema.
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