The rethink on water has impacted many aspects of the mining sector, including the dust management field. A growing list of water-saving dust combatants has hit the market and there is a marked change in the behaviour of industry dust busters.
Those in the dust business confirm miners are increasingly embracing dust control technologies and strategies that use water more efficiently while keeping dust down.
Rather than being driven by industry-wide standards or regulatory requirements, Micro Fresh Filters business development manager Stephen Gledhill said the shift toward water-saving dust control technologies tended to come from individual minesites.
“In general it’s up to the individual minesites to have their own water conservation management plan,” he said. “Obviously there’s just such a limited supply in certain areas ... so they need to do anything they can.
“I think basically they’re all pretty smart about the whole thing. They can see that if they don’t conserve water then they’re going to run into issues. So it’s up to the entire industry to get together and use whatever water conservation means they have available to do that.”
Peter Duffy is South-East Asian division president of BioCentral Labs, a company supplying eco-friendly dust control solutions. He said the greatest demand for water-efficient dust control products came from companies which were directly affected by water access issues.
However Duffy forecast that a combination of community pressure and legislation would eventually force mine operators to reduce the amount of water used to handle dust issues.
Reynolds Soil Technologies technical services manager Paul Heimburger said most miners understood that straight water was not the cheapest long-term dust management solution.
“The future’s always going to be focused on water … and the cost is escalating,” Heimburger said. “There’s cost involved, with costs in transport, plus there are a few mines that are importing water. And they’re the costs they’ve got to wear.”
On the issues of mines and water shortages, Heimburger put it bluntly: “As they’re running out of water they’ve either got to import water or they can’t operate.”
Micro Fresh Filters said its newest dust suppression products could tackle minesite dust problems and reduce water consumption by up to 70% compared to using water alone.
Suitable for use above and below ground, the 3M-manufactured SDS2 dust suppressant is a blend of wetting agents that allows water to penetrate soil faster and be held in the soil for longer.
Also from 3M, the SDS4 treatment combines wetting agents and polymers to treat surface mining dust dilemmas. Gledhill said this treatment formed a flexible, persistent coating on the surface of a treated dust source, without emitting dust if the surface broke.
In addition to their water efficiency credentials, Gledhill said the 3M products reduced slippery surfaces, discouraged evaporation and helped maintain the integrity of the treated surface.
“Every minesite has a responsibility to use products like this to conserve water by any means possible,” he said. “I think the problems we’re having are only going to compound as we see the effects of global warming and it’s products like this that allow these regional minesites to keep operating. When you’re talking about 70 percent reductions, it’d be a brave operator not to use them.”
A drastic reduction in water use was always the key driver behind Cooee Products’ non-toxic dust suppression solution DustBloc. Queensland-based Cooee said the bitumen emulsion-special additive product could cut minesite water use by up to 90%.
Cooee general manager Frank Vos said in the past year or so the company had noted a clear shift toward dust suppression technologies that promoted more efficient use of water, both within the mining industry and among the civil engineering and construction sectors.
“The customers are certainly seeing a marked drop in the amounts of water that they’re using, and the associated costs of using water because of … the number of times a water cart has to be up and down the road to keep the dust down,” Vos said.
In addition, the use of water-efficient minimal application dust treatments could have other flow-on benefits.
Vos said DustBloc could assist with the industry-wide labour shortage as it required one, rather than multiple, applications to do the same job. Workers were then freed up for other more production-oriented tasks.
Although difficult to quantify, feedback from Cooee’s minesite customers also supported the case that its dust product boosted uptime and productivity.
“Production levels start to increase because drivers aren’t driving in dust so they feel safer in that sort of environment,” Vos said. “That’s been a fairly common anecdotal feedback we get from drivers at sites that use our product.
“It’s a very difficult thing to put a cost saving on, in some cases, but when a driver feels safer in what they’re doing, particularly on the night shift, then they’ve noticed increases in tonnages going through.”
Ultimately less water used means less money spent and it is this issue that drives mining operations, particularly in the cost sensitive mining environment.
“With the boom, what we’ve found is that there are quite a number of mines around the place who are looking for a more cost effective way of doing what they’re doing,” Vos said. “It all comes down to per tonne of material and what’s our cost to do that?”
RST’s Heimburger said the challenge to suppliers was twofold – to develop water-saving dust management solutions while educating users about the most efficient use of water.
“They [miners] overwater and they water things like the windrows, the embankment at the sides where they don’t need water,” he said.
Heimburger added that mining companies had only paid real attention to the importance of spray delivery systems, such as water carts and nozzles, in the past few years. In the fight against dust, such systems often need modifying to achieve optimum efficiency, he said.
One such delivery system provider, Technical Projects, supplies spray nozzles for a range of applications including dust control. Its new ultrasonic atomiser nozzle is designed to reduce water usage and was successfully trialled (and subsequently adopted) at BMA Coal’s Broadmeadow coal mine in Queensland.
The nozzle differs from both hydraulic pressure nozzles and conventional air atomising nozzles in that it uses sound waves to break water into fine droplets and create a fog. Technical Projects manager Graeme Cooper told the ultrasonic atomiser used less water than other nozzles and needed only compressed air and water to operate.
During its initial trial stage at Broadmeadow, Cooper said the ultrasonic atomiser attracted interest not only from other miners but also from the CSIRO’s Exploration and Mining division.
Impressed with the results of the ultrasonic atomiser, Broadmeadow mine engineering team leader Greg Magnus said the new delivery system had proved its worth from a dust control and water consumption perspective.
“It grabs hold of the dust particles a little bit better and you use a lot less water,” he said. “I reckon every longwall mine in Australia should have it on.”
As well as the developments in spray delivery systems, Cooper said attitudes toward fugitive dust suppression were also changing.
“As people have become better informed about the principles behind suppressing dust, they now realise that it’s the relative droplet size that is important and that using a lot of water isn’t the best approach,” he said. “It appears that many companies are being more scientific in their approach which can result in considerable savings in the amount of water used, and greater efficiency in their dust suppression.”
