Coleman Microtunnelling has microtunnelled two power plant water cooling lines using a Herrenknecht microtunnel boring machine (MTBM) in Ghana, West Africa.
The Kpone Independent Power Plant (KIPP), located on the coast 25 km from the capital of Ghana, is an oil-gas power plant that supplies approximately one million households with electricity.
In order to facilitate cooling, two water cooling lines needed to be installed to transport sea water from the Atlantic Ocean to the plant.
This type of project required machinery equipped to cope with tunnelling into seawater, so Bothar Boring Australia subsidiary Coleman Microtunnelling ordered a specially designed Herrenknecht AVND2000AB microtunnelling machine with a salvage module.
To construct sea water intake and outfall tunnels, the machine travels from the coastline to the open sea where it’s recovered from underwater.
The addition of the salvage module prevents the machine and the tunnel from flooding.
Crews launched the MTBM from two shafts on the coast to complete four pipe jacking drives.
The first two drives – one at 545 m and the other 520 m – created tunnels from the shaft, running under the mainland, to the power plant.
Connecting to the first drives, the second drive excavated the challenging 1,085 m tunnel from the coast, under the sea floor, to the seabed target for water intake.
After crews retrieved the MTBM at a depth of 17 m, it was used to create a parallel 380 m water outfall tunnel transporting the cooling water back to the Atlantic.
Coleman Microtunnelling Project Manager Brent Jones was impressed with the Herrenknecht support in Schwanau and the Herrenknecht service team responsible for the region.
“We could not have done it without this extraordinary support. All through Christmas, the supply of spare and wear parts went smoothly,” he said.
Herrenknecht Business Unit Utility Tunnelling Area Sales Executive Middle East Swen Weiner said that this performance is a good indicator for the future.
“The good project performance for the long sea-outfall drive in Kpone will be a benchmark for the future in the region,” said Mr Weiner.
For more information visit the Herrenknecht website.
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