Right mix to fix road dust issue

It's amazing how many worldly problems two mates can solve while doing a spot of fishing.
Earlier this year, outdoor enthusiasts Grant Lewis and Lance Aukett were busy hauling in some nice fish when talk turned to the dusty, pot-holed and corrugated metal roads many Northlanders endure by right of where they live.
If it's not wet, slippery winter surfaces, it's the summer dust that slathers everything within 100m of the road.
They were not content with just talking it up - within months the pair had established a business to deal with the problem.
Mr Aukett, a contractor, and Mr Lewis, a developer, had both experienced problems with shrinking and swelling clay surfaces under road bases and felt there had to be a better way to work with the sub-grade soils. The pair decided to investigate alternatives to the normally used lime and cement stabilising products. They particularly wanted stabilisers that would be environmentally friendly and act as dust suppressants.
They trialled products from three companies with some successes and failures. Throughout their research, the name of one corporation servicing major mining companies in Australia kept popping up.
They made contact with the Australian company and from there things progressed relatively quickly. Rainstorm's products use a polymer emulsion, which mixes readily with water and can be sprayed on to or mixed into the surface being treated, leaving a strong wind- and water-resistant bond.
"The fact that the products not only stabilised and compacted but also acted as a dust suppressant, and were environmentally benign, ticked all the boxes," said Mr Lewis.
Along with their wives and a third partner, Jeff Clague of Tomarata, Gravel Lock NZ was established from a base at Waipu in May. "We've created a good relationship with our supply company and have entered into an exclusive arrangement with them," said Mr Lewis, who is the new company's director.
"We now have access to product ranges being offered for the first time outside of Australia, and have the benefit of their 25 years' experience in dust control and road stabilising."
Rainstorm representatives flew over and gave advice on what products would be most effective on New Zealand soils and gravels. "This advice has been invaluable in selecting the best range for our conditions," said Mr Lewis.
The company are able to create stand-off pads, pressure races, feed pads, roads and driveways. Mr Lewis said the Gravel Lock products kept the surface at an optimum moisture content, which ensured it bonded well with a variety of organic and inorganic aggregates. "In most cases we can treat the existing materials in an area without the need to apply additional gravel - it sets like concrete."
He believes one of the four products used by Gravel Lock - PolyMag - could be used by councils to control Northland's road-dust problems. PolyMag has been used in arid mine sites in Western Australia and Nevada since 1983, and on public roads in Tasmania, British Colombia and parts of Australia since the 1990s.
Mr Lewis says the product, which is easy to apply, creates a smooth, hard surface which requires less repairs, maintenance or topping up with gravel. He said dust was recognised not only as a nuisance but a health risk to humans and animals, and compromised road safety because it reduced driving visibility.
It also has an impact on agriculture and horticulture because it reduces weight gains in stock, degrades produce quality, lessens the effectiveness of pest and weed control and contributes to the silting up of waterways and drains.
The company currently offers three products: PACZYME - an organic soil stabiliser; PolyMag, a road-dust suppressant and Glueon 500, a gravel stabiliser. A fourth product - Rainstorm Cement, a binary two-part Magnesia soil cement - will be released early next year.
Trials are available now. "We have had great success over winter applying these products into the private sector for homes, driveways and farm races, and look forward to providing our services across the broader spectrum for larger companies and organisations requiring cost-efficient roading and maintenance and dust solutions," said Mr Lewis.