A COMBINED 65,700 cubic metres of material was removed by Neumann Contractors in dredging works recently completed by the company in Queensland’s Burnett River.

The sand and gravel was removed from channels in the river restore the depth of the river’s navigational channels after it was severely impacted by flooding in January 2013.

The work, which was jointly funded by the Queensland Department of Transport and Main Roads and the Department of Natural Resources and Mines, was performed upstream and downstream of the natural Kirby’s Wall rock formation, with the removed material being deposited behind it.

The channels were dredged to a maximum depth of 2.3 metres at lowest astronomical tide (LAT), with the material spread evenly behind the wall to a height below +0.3 LAT.

Neumann used its 450mm Cutter Suction Dredge Nu Endeavour to perform the work, connecting a booster pump and pontoon directly to the rear of the dredge to extend its pumping capability to reach the required distances to the disposal area (up to 1,700 metres).

The Nu Endeavour was coupled to a spreader barge for placement of the dredged material behind Kirby’s Wall.

It used a three wire anchoring system, allowing it to winch across the fill area while the material was being discharged.

Floating pontoons was employed adjacent to Kirby’s Wall to ensure the anchor lines didn’t come into contact with the top of the wall and cause damage.

Neumann also used a barred Bucketwheel to exclude oversize material from the pumping system, as well as workboat the MV Tramp, a fuel barge; an anchor barge and a number of smaller tender vessels.