BHP has recently constructed a Hot Briquetted Iron Plant at Port Hedland in the Pilbara region of Western Australia. Supply of iron ore fines to the plant is by conveyor from the company's existing Nelson Point stockyards. The conveyor passes under Port Hedland harbour in a concrete segmentally lined tunnel, approximately 1030 m long and with a 5.1 m external diameter. The tunnel was constructed by a Tunnel Boring Machine (TBM) which both excavated the ground and erected the tunnel lining. The tunnel was bored between cut and cover in situ concrete portal structures, the TBM being launched from the Finucane Island side towards Port Hedland town. The alignment required lengthy gradients of 1:6 on either side of the harbour's dredged channel, under which the tunnel is bored with a minimum clearance of 8 m._x000D_
The tunnel is fitted-out with: 1800 mm belt conveyor capable of 10 000 tph; walkway along which a specially designed inspection/ maintenance vehicle can run; and tunnel services including power, light, fire detection and suppression communications, water mains for wash down and sumps and pumps for drainage._x000D_
This paper gives a general overview of the design and construct contract, important aspects of the design and the construction process itself.