Car dumpers for iron ore sites

PROJECT delivery, engineering and sciences firm, Sinclair Knight Merz (SKM), is providing leading technology and project management for new and upgraded car dumpers for the mining sector.

Since 1998, SKM has designed new, or upgraded old, car dumper facilities on seven BHPB Iron Ore and Rio Tinto Iron Ore sites in the Pilbara, Western Australia as part of EPCM contracts.

For Rio Tinto Iron Ore (RTIO), these have included Car Dumper 2 (CD2) at Cape Lambert, CD3 and CD4 at Parker Point, Dampier, and CD2 at East Intercourse Island, Dampier. For BHP Billiton, SKM has worked on CD3 at Nelson Point, CD4 at Finucane Island and an upgrade to CD1 at Nelson Point, all at Port Hedland.

SKM Engineering Manager, David Booth, said SKM had utilised technical expertise, efficient project management, effective safety procedures and innovation to deliver the projects.

“The work often has to be undertaken during a shutdown scenario, so ensuring the project is completed on time is essential,” Booth said.

“Work areas are congested, and critical heavy lifts are involved, so detailed planning of activities, to enable them to be executed safely, is of the utmost importance.

“Utilising technical expertise and innovation to design, upgrade, construct and deliver the equipment to site is also vital, and SKM has succeeded in each instance.”

Booth said a good example of a car dumper upgrade in practice was the East Intercourse Island CD2 (EIICD2) which was commissioned in September 2006 and had been operating successfully since. It contributes up to 50 Mtpa of the future 220 Mtpa capacity of Rio Tinto Iron Ore’s port facilities and shipping capacity, which will be reached in 2009.

The original East Intercourse Island single car dumper was a single cell unit that tipped two ore cars. This dumper cell was supported at each end and was rotated by two drives onto a single drive rack at one end of the cell. After 25 years it had reached the end of its operating life and needed to be replaced.

The car dumper was to be replaced by a twin cell, two car configuration, with four sets of trunnion support rollers and one drive per cell.

The project consisted of two phases. The first occurring over the 18 months preceding the installation, was the fabrication of the new car dumper, which comprised two rotating cells and associated drives and controls, and preliminary pre-shutdown work. The second phase was the removal of the old single cell two car “barrel” and installation of the new twin cell two car machine during an 18 day shutdown.

The new car dumper cells were fabricated and trial assembled in Perth, prior to road transport to Dampier in piece-small components. The cells were re-assembled at the car dumper facility.

The old single cell was supported at each end by a set of trunnion rollers, requiring a total of two sets of trunnion rollers.

Each new cell also required trunnion roller supports at each end, thus requiring a total of four sets of trunnion rollers. The extra two sets of trunnion rollers required the installation of a set of centre trunnion support beams and associated structural supports, following the removal of the old single cell and its trunnion support rollers.

“The challenge was to install the new support structure in the middle of the building where none had existed before,” Booth said.

“We had to remove the old single cell and install two new cells, while working alongside another contractor who was overhauling the ore car positioner, that was located adjacent to the car dumper, as part of RTIO operations maintenance activities.

“The work area was congested, limited by the size of the original dumper’s concrete structure, existing infrastructure, and topographical features. A large 850t heavy lift double crawler crane was assembled and commissioned alongside the dumper to remove the old cell and install the two new cells.

“This large crane further added to the congestion.”

The CD2 facility was shut down for 18 days, and to enable the various works to progress concurrently without incident, the separate Project and Operations work areas were formalised with a “Blue-line” work area demarcation.

Studies were carried out examining the various work tasks, taking into account the work crews and various crane activities, which resulted in critical heavy lifts occurring during the day where possible.

A three shift 24-hour day system was run during the shutdown for the workforce, using a staggered start/stop time that enabled continuity of activity at work fronts. EHS personnel and engineering support worked a two shift 24-hour day system, which provided overlap of supervision across the three shift system.

“The works were completed after only 16.5 days of the 18 day shutdown without any Medical Treatment Injuries or Lost Time Injuries,” Booth said.

“The dumper was at full production one week after the completion of the shutdown and it has performed to expectations since.”

Key contact:

David Booth

Engineering Manager Mesa A, Area Engineer EIICD2 & CD4

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