Four companies ‑ spanning dust suppression, engineering and safety – are joining forces to offer products and services aimed at better haul road safety, economics and dust control.
Mine operators typically face a continuous struggle when trying to balance dust suppression and overwatering on mine haul roads.
The aptly named Haul Road Optimisation Alliance is made up of Australian Diversified Engineering (ADE), Proof Engineers, Road Safety Training Services, and Reynolds Soil Technologies (RST). It aims to provide solutions to the many challenges mine operators face in controlling dust and road safety on site.
ADE general manager, Clive Gray, said recent audits of water trucks and road watering techniques at more than 30 mine sites have revealed that many water trucks are applying over 50% more water than necessary, which can result in major safety issues while affecting productivity.
“If an operation overwaters its haul roads in an attempt to battle dust, it creates the risk of an uncontrolled movement, when a vehicle is involved in a slide or rollover,” said Gray. “This can result in severe safety incidents as well as significantly reduced productivity on site by leaving haul roads closed for hours or even days.”
On a financial level, poor water usage can result in mine sites having to import water from external sources at high costs, whilst poor road management and overwatering can result in increased road maintenance and mobile equipment maintenance. Furthermore, if legislation is breached, mine sites can incur financial penalties.
A mine operator can reap significant savings by consistently applying the correct amount of water to a haul road. For example, on a dry site with an unsealed haul road, an operator may need to apply four litres of water on every square metre, every day, in order to effectively suppress the dust.
This is equivalent to spraying 0.3mm/m2 of water onto the road, thirteen times a day which, if multiplied across a ten kilometre haul road, is an enormous amount of water being used.
If the ten kilometre haul road has the site average width of 32 metres, the mine would be using 1.2 million litres every day just to keep dust under control. Overwatering by even a small percentage can equate to a large quantity of water being wasted, while reducing the amount of water applied means a truck can spray more road in a single tank, meaning mine operators can increase the capacity of their current water truck fleet.
To determine how much water can safely be applied to a haul road, a company pioneered by former and current Police Forensic Crash Investigators, RoadSafety Training Services, has designed a surface friction protocol specifically for mine haul road networks.
The safety protocol, endorsed by the Queensland Mines Inspectorate, classifies mine haul roads using a Global Road Friction Risk Model to specify a safe water application rate, expressed as mm/m2, so that a minimum level of grip in the road is maintained after watering.
Working collaboratively with RoadSafety Training Services is Australian Diversified Engineering (ADE), developer of the ECO Spray Premium, a water truck spray system that uses a defined input to achieve a measurable output, which allows operators to input a set rate expressed as mm/m2, the same format used by the Global Road Friction Risk Model.
“By utilising the remote-operated ECO Spray Premium system, mine operators can ensure no water is wasted while still maintaining a safe level of friction on their haul roads, removing the guesswork from dust suppression and ensuring optimum productivity from every water truck,” said Gray.
“Another factor that can significantly improve the capacity of the current water truck fleet is the addition of Reynolds Soil Technologies’ (RST) road stabilisation and dust suppressants ‑ polymers that assist dust control even after the water has evaporated, resulting in more time between required spray cycles.”
The final component of the Haul Road Optimisation Alliance is a new technology from Proof Engineers, a tool called the Proof Mobile Dust Monitor, which monitors wheel-generated dust‑ one of the largest contributors of fugitive dust on a mine site ‑ in real time.
“Technological advancements continue to change the way the mining industry works, and haul roads are no exception to this trend,” said Gray.
“By undertaking a broad review of haul road management, mine operators can gain greater knowledge of their operations, leading to more efficient haul roads and the ability to significantly improve productivity and road and dust management operations.”