The originator of the idea is Brisbane mining engineer, Aaron Trevis, who formulated the concept in 1995, while serving an 18-month stint underground as part of his engineering degree. Trevis said he was unimpressed by the cumbersome shuttle car bumping its way over rough terrain ferrying coal to the conveyor belt.
“There had to be a better way,” remembered Trevis. “The problem was that the mining wasn’t continuous – the further out the shuttle car went from the coal face, the slower the process became.”
Trevis and partner Steve Smith, who owns SWS Engineering, designed the concept of piping coal in slurry form, rather than transporting it by shuttle car. The two formed a company, Eikon, which holds the intellectual property rights to the concept, and linked up with G & S Engineering in Mackay – a company offering engineering and maintenance services to the mining industry.
In June the group was granted R&D Start funding from the Federal Government to progress the concept, comprising a percentage of the total project costs, with expected completion of the R&D project being December 2004.
“While pumping is commonly used in mining, it hadn’t been used in this application and the machinery was accepted as being an inventive and innovative step in the industry. From a mine operator’s point of view, it was heaven-sent. The industry has recognised the serious risks related to the shuttle car, ” Trevis said.
“I thought how great it would be to pipe the coal and walk the underground roads without the threat of being run over by a shuttle car. I realised there was enough existing technology to make it work but there were a lot of practicalities, redesign and trials ahead.”
Some key issues will be sizing raw coal down to 50-70mm and getting the pumping technology right. At this stage positive displacement piston pumps will be used. These ultra high concentration pumps are generally similar to designs used in the concrete pumping applications.
The pump will be driven by electric motors with working power ratings to be determined after interim development works. The pipeline is expected to be formed of high pressure hoses with a diameter of 250mm, positioned adjacent other services and supported from the roof.
A high concentration slurry process is envisaged, allowing a coarse mix (10-15% water content) to be used where slurry travels as sliding bed. The slurry is considered stable and more resistant to blockages compared to conventional, turbulent flow slurries.
In Stage 1, a 250m transport distance is targeted but this could be extended once technical glitches are ironed out. Complete construction of a full prototype is due for completion in December 2004 with underground testing and system validation expected to be completed by June 2005.
A surface pumping trial will be run in early 2004 at a mine in central Queensland and Trevis said further interest was sought from mines interested in hosting trials.
“Assuming the technology does what we say it will, the market potential after five years is in excess of $230 million. The need is so great that we can see each unit paying for itself within a year. There is also possible long-term use in other areas of the industry such as metalliferous mining.”
Trevis said there is a big step between the concept and actual working product. Despite technical challenges the benefits, he believes, far outweigh the potential risks, particularly in the area of safety and productivity.
“The local coal industry is under threat and if the rest of the world starts putting more coal into the export market, we definitely need to increase efficiency. This is one way of ensuring we remain competitive.”