How Composite Matting Get Flood Damaged Rail Lines Back on Track
Flash Flooding and a Near Miss
It was a case of mixed blessings leading up to Australia Day 2020 in North West Queensland. A monsoonal low from the Northern Territory created a storm cell promising days of torrential rain. While the heavy downpour was refreshing news to the drought-affected farmers, it was however a cloud of worry for the rail asset managers of the Mount Isa Line, hoping for the best but preparing for the worst.
Then at 6.30am, Sunday the 26th of January, an eastbound freight train barely avoids derailment at the Prairie Creek rail bridge, where the ballast has been washed out by floodwaters.
The fully loaded freight train was able to retract and stabilise at a safe location however the track had to be closed, causing disruption to the rail line between Mount Isa and Townsville.
The Clock Ticks
The Mount Isa Line is a critical supply line from the North West Mineral Province to the Port of Townsville. It is estimated that 75% of freight on this supply chain consists of minerals, acid and fertiliser. Each day the line was closed meant a disruption to Queensland’s export output ultimately affecting Australia’s reputation as a reliable supply partner to global buyers of zinc, copper, lead and fertiliser.
As the recovery team watched the skies during Queensland cyclone season and waited for flood waters to recede enough for detailed inspections to take place, preparations began with a pressing sense of urgency.
Urgent Site Access
Once the flood water levels allowed for assessment, the recovery team identified three locations requiring urgent repair works:
- Prairie Creek Rail Bridge - Replacement of track and ballast
- Prairie Creek Rail Bridge - Repairs on western approach to bridge
- Little Emu Creek Rail Bridge - Repairs to bridge and earthworks
The immediate challenge was how to get the construction vehicles across waterlogged grounds and on to the recovery site. With further rain expected, the ground was not likely to dry in time.
The team drew on the experience from previous year’s unprecedented flooding event. In January 2019, flooding caused extensive damage to the Mount Isa Line between Cloncurry and Hughenden, as well as a derailment at Nelia.
Supporting the 11-week recovery works on more than 200 sites across 300km of track was a heavy-duty interlocking composite mat called Dura-Base, provided by JWA Oilfield Supplies.
The call to JWA Oilfield Supplies was made and shortly after, 16 semi-trailers were organised to transport 1,600 meters of DURA-BASE Composite Mats from the Brisbane depot.
As soon as the first truck arrived on site, installation of the mats began. Each mat provided a working area of approximately 4m x 2m with a thickness of 10.5cm. Building a 4m wide track was a matter of laying one mat over another with twist-turn action locking pins at the overlapping parts.
Within hours, the first temporary roadway was ready for the fleet of excavators, compactors, rollers, bulldozers and trucks to commence rebuilding work.
Weatherproof with Minimal Soil Disturbance
Each 450kg panel interlocks together to create a continuous surface safely supporting high traffic of heavy wheeled and steel-tracked equipment. Made of durable HDPE, the composite mat roadway was not affected by further rains during the repair operations.
The thickness of the matting also served to minimise topsoil disturbance from construction traffic, and acted as a control measure for sediment and erosion management.
Repairs Completed Ahead of Schedule
The scope of works was initially expected to take over 3 weeks, however combining the tireless efforts of 60 Queensland Rail employees with uninterrupted site access, the job was completed with the track certified fit for service in 2 weeks.
JWA Oilfield Supplies have been supporting Australia’s resource and construction sector with composite matting solutions for temporary access and work platforms since 2003. To find out more about the DURA-BASE Composite Mats, click here or call 1800 264 628.