Caval Ridge - Mud Dredging

Mud Dredging

Principal: BHP Billiton Mitsubishi Alliance

Location: Moranbah, Queensland

Contract Value: $3,000,000

Completion Date: August 2014


In April 2014, Neumann’s were contracted by BMA to remove 475,00m3 of mud from the floor of an open cut coal mine as part of preparation for reopening the pit. 

As the pit had been disused for some time, mud had been carried into the pit from surface runoff and accumulated in the pit floor. The task was to dredge this mud and pump it out of the pit for placement in an adjacent excavation. 

The 450mm bucketwheel cutter suction dredge Nu Bounty was mobilised for this project along with a booster station and 2500m of pipeline. A return water pump and pipeline was also mobilised to transfer water back from the discharge area to the dredge pond to enable an orderly draw-down of the water level in the dredge pond. 

All equipment was diesel powered. 

Innovations 

  • Management of pumping through a 40m vertical pipe section to the booster pump located on the cast bench 
  • Trialling of a discharge restriction valve to manage pressure at the discharge line highpoint while maximising the siphon effect 

Challenges 

  • Water levels and draw-down had to be carefully managed to maintain geotechnical slope stability
  • Strict design cut conformance was managed and reviewed using on-board RTK navigations systems
  • To expedite the work dredging was carried out on a 24/7 basis

See Dredge Specification for Dredge 7 - Cutter Suction Dredge Nu Bounty

See Other Dredging Projects