March/April 2007

New technology for smarter blasting

By C. Hersey

If someone were to offer you fifty dollars for every one dollar you invested, would you commit? If you’re like any other human on the planet with a pulse, you probably wouldn’t think twice about it. A new electronic blast movement monitor, mutually developed by the Julius Kruttschnitt Mineral Research Centre (JKMRC) and Blast Movement Technologies (BMT), revolves around exactly that concept - invest a little, gain a lot.

Currently, most mines are using a range of techniques to measure muck pile movement, from sand bags and poly-pipe to electronic sensors. The possibilities are endless, but the results never quite as good as they could be. Ore loss and dilution due to insufficient techniques can add up to tens of millions of dollars lost per mine per year.

For example (with an ore block 50 metres wide and a flitch five metres high), missing the ore boundary by just one metre can result in up to AUS$100,000 of lost gold. According to Darren Thornton, senior research officer at the JKMRC in Indooroopilly, Australia, this new technology could save the industry an extra five to ten per cent, a considerable amount for a small investment price.

Research on the Blast Movement Monitors (referred to as JKBMMs) began back in 2003, and they have since been used in several mines with results generating much interest among intrigued mining companies around the world. The JKBMMs are used to accurately measure ore movement, in turn decreasing ore loss and dilution, and thereby increasing profits and revenue. The technology is really quite simple. The JKBMM is a directional transmitter encased in a protective shell (typically the size of a softball) and has about eight hours of battery life immediately after having been assembled. These transmitters are then placed in separate drill holes (which are selected according to desired blast outcome) prior to blasting. After the blast, a directional receiver, much like a metal detector, is used to detect the signal produced by each transmitter. The horizontal location of the JKBMM is recorded and its depth is determined by the strength of the signal. Once all of the JKBMMs and their respectful positions have been accounted for, calculations are made to determine the three-dimensional movement vectors of the transmitters. With the help of these blast movement monitors, the movement vectors for each JKBMM can be available in less than an hour (for approximately 12 JKBMMs), saving time and money normally spent on trying to recover traditional visual markers.

Paul Adams, who works for Porcupine Joint Venture in northern Ontario, has been using the system since last January and can’t imagine how in the world they ever got along without it. Before the JKBMMs came along, workers were forced to dig through muck piles before even knowing the movement of the ore. Waste was being shipped off to the concentrator, while ore (mistaken for waste) was being hauled off to the waste dumps. Translation: loss of revenue, unhappy concentrator, and reduction of profit. Also, traditional markers, such a shovels or poly-pipe, were difficult to recover, if at all, and the time spent finding them resulted in movement information that was too late to be useful. Since implementing the technology, Adams stated that they can now predict ore movement much more accurately, both dilution and ore loss have decreased significantly, and profits are up. One blast test performed at Porcupine using the JKBMMs already revealed enthusiastic results; dilution had decreased by approximately 11.4 per cent and ore loss by approximately 7.6 per cent. “I love these things; they really improve the way we work around here,” Adams said with definite enthusiasm.

Based on the success of current results, research will continue in this area of blast engineering and ore control. There are still aspects of the system that have not been fully developed, and there are likely some improvements to be made to ensure its practicality for everyday use. According to research officers at both JKMRC and Placer Dome Technical Services Limited, some topics could possibly include:

  • Extending the transmitter’s battery life from eight hours to several months
  • Reduction of the transmitter’s diameter to allow entry into drilled holes smaller than 100 millimetres
  • Improving the survival rate of transmitter electronics and protective case
  • Developing unique identification for each transmitter to permit multiple units per hole
  • Improving transmission through more than 10 metres of rock
  • Developing models and software to link with ore block modelling packages

Despite it still being a relatively new product on the mining market, the advantages of this technology are impossible to ignore. Amidst today’s current blasting techniques, JKBMM has stolen the spotlight. It is possibly the only efficient method available today to accurately measure blast movement, in addition to not requiring a massive capital investment in consumables (thanks to disposable transmitters). For a mere few cents extra per ton of rock blasted, open cut mines around the world can be reaping the rewards of this new technology. The system provides results much sooner after blasting and before excavation commences, and there is little interference with current blasting operations. The transmitters themselves are more easily detected than visual markers such as chains or shovels, and, being disposable, there is no precious time or money spent trying to recover them. Of course, the biggest benefit from the JKBMM is the overall better grade product. Less waste and more ore spells better business, higher profit, smiling concentrators, and more revenue for any open cut mine. Soon enough, JKBMM fever will be spreading like a wildfire and more popular than bell-bottoms in the 60s.

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