Published in the January 2010 Australia’s Mining Monthly

A gantry stacker is the preferred means to provide this, at least for WICET stage one.

The approach was proposed by Aurecon Hatch, which also has designed the stacker.

As far as Aurecon Hatch is aware the only other time this has been tried is in Los Angeles at the LAX coal terminal. That unit, which ran for a while in the 1990s, was about three quarters the size of the one planned for stage one of WICET.

A builder for the WICET gantry stacker is yet to be appointed.

The WICET stage one owners Aquila Resources, Bandana Energy, Caledon Resources, Cockatoo Coal, Northern Energy Corporation, Wesfarmers Curragh, Yancoal and Xstrata Coal wanted to be able to blend up to five different types of coal with very close tolerances.

Blending is a growing marketing tool in mining. Rio Tinto has been doing this sort of thing with iron ore for years. Indeed, it has built a competitive advantage out of it. The attraction of being able to do it for the WICET owners is obvious.

However, cross contamination from coal dust from other stockpiles is one of the bugbears of blenders.

A lot of this dust comes from the dozer push operations used to create these coal stockpiles.

This is one of the reasons WICET also wanted to reduce the number of dozers it would need to run its stockpiles.

The gantry stacker would allow WICET to halve the size of the dozer fleet it would need to operate a 25-30Mtpa facility, the size stage one is expected to be.

The assigned operator – the Gladstone Ports Corporation – already has lots of experience with dozer push operations at its RG Tanna facility.

Aurecon Hatch consultant (mechanical) Jim Harrison told Australia’s Mining Monthly one of the key aims for the WICET terminal was to reduce its dust signature.

“They realised dozers were one of the main dust causers,” he said.

The gantry stacker operates on two rails, just like a gantry crane does.

However, following the gantry crane example, in the place of the hook there is a discharge chute for the coal. This “chute” can move anywhere within the rails, just like a gantry crane hook would.

The gantry stacker simply moves over the various stockpiles adding the coal to each as required by its blend.

Harrison said the stacker would be fed by a 6000 tonne per hour conveyor.

It also has its own transformer and switch room and an umbilical cord for its power and water needs.

“The unit knows exactly to the millimetre where it is at any one time,” Harrison said.

“Its controllers can decide where it needs to go. It goes there, checks to see there’s nothing in its path, and then starts operating. A completely unmanned operation.”

At this stage only one of these gantry stackers will be required. However, there are plans for two more to be added in stage two of the terminal and a fourth to be put in with stage three. By that point the terminal should be pushing out 70Mtpa.

Harrison said, however, that the proponents would reassess the gantry stacker situation as part of the planning for stage two.

WICET appointed Worley Parsons to provide procurement and construction services for stage one of the terminal earlier this year. It hopes to have final approval of the procurement and construction management contract in early 2011.

It also has appointed the Australia and New Zealand Banking Group as financial adviser to help secure stage one funding.

The deadline for coal producers seeking new or additional capacity through an expansion of the terminal closed on August 31.

“Reaching these milestones demonstrates that an industry-funded terminal offers real benefits for coal producers,” WICET project director Mark West said.

Financial close for the project is expected in the first half of 2011, with first shipments from the site expected from 2014.

Infrastructure bottlenecks are the main driver behind WICET.

Coal is Queensland’s largest export, worth $30.3 billion in 2009-2010. That is expected to double over the next decade. The trouble is, the existing ports are at maximum capacity.

Harrison told the Bentley Systems Be Inspired conference in Amsterdam in October that Aurecon Hatch had gone for the most energy efficient design it could for the WICET project.

Using the gantry stacker effectively halves the fuel burn because the dozer fleet has been halved.

Harrison said the design called for the use of solar power as much as possible, uses variable speed drives for the conveyors and will harvest and reuse as much of its water as possible.

“This is a huge project,” Harrison said. “There will be $12 billion additional export income from this terminal.”

The community around Gladstone had indicated some concerns about the potential dust issues from the WICET site.

Aurecon Hatch was able to mitigate these concerns through some clever use of three-dimensional modelling. The firm was able to set up a fly-through of the proposed terminal.

“The use of 3D models gave us the conduit to allow the plant to be shown to the community so they could understand it,” Aurecon Hatch senior project engineer Andrew Hauff said.