‘MINING CHRONICLE’, October, 1998
(supplied with 3 selected illustrations)

State-of-the-art expansion adds

12m tonnes to BHP Iron Ore flow

by Brian Jenkins

When BHP Iron Ore embarked in 1996 on its objective of a major increase in ore handling capacity at Nelson Point, Port Hedland, its policy was to deploy Australian services to the maximum extent—with preference to installing plant equipment manufactured in Western Australia.

The leading Australian engineering consultant Sinclair Knight Merz (SKM) was selected to manage the project, having a 34-year record of service to mining industry and a recent local achievement in completion of the Port Hedland power station for the Pilbara Energy Project. SKM's experience in materials handling includes design of a major expansion of shiploading facilities at Newcastle for Port Waratah Coal Services.

With engineers, planners, scientists and ancillary staff totalling over 1500 people in 27 offices across Australia, the Pacific and South East Asia, SKM has the resources, financial standing and technical capability to undertake projects of any magnitude and has been awarded many prestigious developments in the region, including project management of the Olympic Games stadium in Sydney.

No stranger to Western Australia, SKM provides consultancy services to Alcoa, has supervised construction of power stations, including the Kununurra hydro-electric plant, and of Perth's "Access" freeway upgrade.

BHP’s Nelson Point plant receives material railed from the Newman and Whaleback mines, which is processed and screened as lumps or fines and routed either to shiploading for export customers or to the company's new Direct Reduced Iron (DRI) plant at Boodarie.

Fine ore is co-produced with lump ore. While the DRI process can use fine ore, blast furnaces preferentially use lump ore. Predominant export demand for lumps creates a world surplus of fine ore and depresses its price. By opening an additional market for fine ore with a hot-briquetted iron (HBI) process, BHP enables additional production of the more saleable lump ore.

The 1996 brief was to eliminate bottlenecks and increase throughput capacity from 52 to 64 million tonnes per annum over a 2-year redeveloment period. Key elements in the contract, following a feasibility study, were the provision of:

• a new 10,000-tonne-per-hour rotary ore dumper handling two rail wagons at a time, to be constructed and commissioned without interruption to throughput of the existing smaller dumper;

• construction and/or modification of 21 conveyors totalling 3.4 km in length, with computerised instrumentation and controls;

• upgrading of crushing and screening facilities

• modifications and enhancement of power distribution and transfer stations.

• New and modified software for overall plant monitoring and control, including touch-screen control over route-selection

The feasibility study was completed in 1996, following which SKM built a village to accommodate the projected workforce of up to 500 .

Project manager Mr Jack Rowley said construction of the car dumper had begun in April 1997. Commencement of the conveyor package followed in September, and the upgrade of Plant 2 crushing and screening in November, 1997. The target date for completion was June, 1998.

The complexity of the task was compounded by its location within the existing operating plant which required modification to ensure that material from the original dumper was conveyed to the new storage stockpiles.Two conveyors were built for that purpose.

Detailed shutdown planning programs were conducted with the desired result that there was no pause to the shipment of ore and, in fact, BHP achieved record production rates in the period.

The footings of the diaphragm walls and galleries beneath the new car dumper extend 17 metres below ground level to the underlying conglomerate rock stratum. The excavation was a site of complex and monumental reinforced concrete works to house the hopper and apron feeder beneath the giant rotary dumper. Large-vehicle access is provided by a ramp from ground to the lower levels .

Professionals in SKM’s Perth office provided the sophisticated design amd phased-construction program, all details of which were available on-line both to the site engineers and to BHP management.

'Walk-through' 3D visualisation software allowed the entire project to be modelled and constructed in a virtual environment. This enabled close monitoring and linkage of each step of the construction process, with spin-offs for progressive procurement data and client communications.

SKM’s responsibilities included safety provision for the workforce which peaked at 450—an exacting task in view of the scale and complexity of the operations which involved considerable innovation in progressing from a brown-field site, synchronising with parallel production and installing a variety of very heavy components with large cranes. The firm’s established safety policies and management practices proved equal to the task.

BHP was able to announce in its August 1998 report to shareholders that the forecast final cost for the project was within the approved budget of $348.3 million. All work had been completed with the exception of the delivery of two new locomotives (by a separate railroad contractor) and the upgrade of control software.

It was further reported that more than 1.5 million hours have been worked on site for a Lost Time Injury Frequency Rate of 3.2 injuries per million hours worked.

ends