Australian Diversified Engineering on the importance of haul road safety

An important safety report was recently released by the NSW Government that showed that there were over 20 incidents reported between January 2017 and February 2018 that involved the loss of control of a vehicle caused by over-watering of roads.

The overwatering of roadways where mining vehicles regularly travel severely decreases tyre traction which in turn increases braking distance and time. It can also contribute to dislocation of fill slopes and cause severe erosion.

Because haul trucks and other vehicles on mine sites find it more difficult to stop on wet roads, over-watering can result in vehicles losing control and crashing into infrastructure, other vehicles or safety berms.

In reviewing the circumstances reported, mine operators have not acknowledged whether there were other contributing factors than a wet road surface. The issues of road construction or materials used in the road construction, road slope/grade, tyre condition, drainage, when the road was last maintained, and if water operations coincided with a rain event, were also not identified as causative influences in the incidents.

ADE Sales Manager, Eric Tomicek, supplied some valuable information about what this new report means for the industry in terms of safety, how overwatering haul roads can affect your site’s efficiency and how companies can adopt certain products and procedures to improve their sites.

Mr. Tomicek said this report is very important for the mining industry.

“Roads are watered to minimise fugitive dust emissions that not only effect workers and equipment on the mine site, but people and livestock in the surrounding community. For a long time, dust suppression was the priority, this report brings to light a major hazard created by water cart dust suppression; over watering of haul roads,” he said.

The findings of the report will affect safety in the industry. He said that operators in the industry were going to have to implement processes that ensure optimal water application for dust suppression. This means not overwatering roads so that they become slippery, but still applying enough water to effectively manage fugitive dust emission.

“This is a great opportunity to dramatically improve a fundamental aspect of open cut mining. The haul road is the backbone of the mine and when poor fugitive dust management practices occur (such as overwatering), production cycle times increase as the average speed of the haul trucks is reduced to manage the adverse haul road conditions” he said.

“Improving fugitive dust suppression procedures will ensure efficient haul road operations and maintain optimum production.”

Overwatering haul roads affects a site’s efficiency and it is vital for operators to make changes. There are certain types of procedures that industries should take on board to prevent these types of incidents in the future.

Mr Tomicek said, “Think about what happens to our cities road networks after it rains; the now slippery roads slow traffic, create congestion and unfortunately sometimes will lead to an accident.”

“How much water should be applied to the haul road to optimally suppress dust but not make the road slippery? Up until a few years ago mine management and water cart operators haven’t had the tools that are required to determine the optimal water coverage rate without sufficient knowledge of key aspects such as water output or road material. Sites need to implement procedures that measures the risk and then forward on the relevant information to the water cart operators to manage the risk.”

There are of course several products and methods that can be used to measure and understand how friction is affected after road watering.

“As a priority, miners need to learn how to measure friction and understand how friction is affected after road watering. ADE provides training and the tools to measure friction and supply a water cart spray system designed to work with the output of mine haul road friction testing” he said.

Mine operators should take all contributing factors into consideration when reviewing control measures. They should also review the suitability of the materials used on roads, as well as construction and design of ramps and roads. Training should also highlight appropriate actions in response to a loss of vehicle control.



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