BHP Iron Ore Capacity Expansion Project
Abstract
The new No. 3 Car Dumper, constructed as part of BHP Iron Ore’s Capacity Expansion Project at Port Hedland, is a two cell rotary iron ore rail car dumping facility which extends 25 metres below ground and includes a load-out tunnel rising from the bottom of the car dumper to ground level over a distance of 150 metres. The permanent car dumper and tunnel structures were constructed using purpose-designed concrete and required one of the deepest temporary vertical ground retention systems undertaken in Australia, as the new facility is located between the two existing car dumpers and operating rail lines. The civil works were complicated by highly variable ground strata and a saline groundwater table only metres below ground level. Given the stringent durability requirements to achieve an adequate design life in an aggressive environment, close attention was paid to concrete specification, batching plant establishment and control, trial mixes, reinforcing detailing, joint detailing, waterproofing, crack control, strength design and construction quality. This paper presents the approach taken to address these requirements for this remote area project.