Concrete for the Western Harbour Crossing approach roads, cut and cover tunnel and the ventilation buildings came from what is believed to be the biggest 'batching plant' in the world. Pioneer International's 'quality assured' Ap Lei Chau plant is thought to be the largest concrete batching plant in the world, capable of producing 400 m3 of quality-controlled concrete an hour. With four mixing points and more than 90 mixer trucks, Pioneer was able to supply Gammon Construction with 200,000 m3 of concrete for the construction of the approach roads, cut and cover tunnel and the ventilation building at Sai Ying Pun. Pioneer was also responsible for supplying Kumagai Gumi with 180,000 m3 of a special concrete mix produced from a purpose-built plant set up at a disused quarry at Shek O. The concrete used by Kumagai to construct the immersed tube sections of the tunnel needed to have high durability, so close co- operation between the contractor and engineers was needed to produce a concrete mix that offered high performance and was resistant to sea water and the elements. Pioneer erected a further on- site plant on the West Kowloon reclamation to provide Nishimatsu Construction with 70,000 m3 for the construction of the northern entrance to the Western Harbour Crossing. Pioneer was also awarded the contract to surface the roads within the tunnel.