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New Zealand’s South Port to dredge historic rock sediments

2022-08-25 Tamara Parkin

23082022 // heron_construction_slide.jpg (143 K)

Photo Credit: Heron Construction

Heron Construction Company has been contracted by New Zealand’s South Port to remove fragmented rock from the port entrance channel by dredging this material. The New Zealand company will remove rock sediments created by previous blasting works to the channel in the 1980s. At the time, engineering limitations meant the rock sediments were impossible to retrieve. The removal of these fragmented rocks will prevent potential impediments to planned future capital dredging operations. 

The dredging was scheduled to begin between 15- 21 August and be completed towards the end of September.The work will be carried out under an existing coastal permit issued by Environment South under the Resource Management Act. The six-week clearance period does not include any blasting activity. 

A GPK De Donge “B” type backhoe dredger will dredge part of the entrance channel at Bluff Harbour. The GPK is a 45m x 15m Donge Flushing Yard (DFY) B-type backhoe dredger named after Heron Construction Ltd’s late director Gerard Paul Kroef. The B-type dredger has increased stability and accessibility to lower sheaves. Heron equipped this pontoon with a Liebherr P9150 excavator, which can dredge up to a depth of 19 metres. 

South Port does not anticipate any major disruptions to commercial or recreational users of the channel as the dredging plant will remain stationary whilst in operation. For larger vessels, the dredging plant will be relocated outside of the channel boundary to allow safe navigation. 

This dredging project is one of several underway in New Zealand at the moment. The Opotiki District Council confirmed in July that dredging will commence in the Opotiki Harbour Development Project. This work will widen the harbour entrance to allow access for larger boats. Whilst Eastland Port’s Twin Berth project is close to submitting its stage two application which includes dredging of the channel and harbour. 

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