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01/11/2013
Powering up the Pilbara

The number of Australian greenfields projects is shrinking, primarily because of the risks associated with long exploration times, minimal infrastructure, and exploding costs.


So when Fortescue Metals Group decided to develop its $3.2 billion Solomon iron ore mine located in the Hamersley Ranges, west of Fortescue’s existing Cloudbreak and Christmas Creek mines, there was a lot to consider in terms on infrastructure development.


Namely a $1.2 billion port and loading facility, rail infrastructure which is expected to cost about $850 million and a further $850 million to develop the mine itself.


The Solomon Hub includes the Firetail operation which commenced mining activities late last year, transporting first ore in December and the Kings mine which is scheduled for completion later this year, lifting Solomon’s total production capacity to 60 million tonnes per annum.


“The Solomon project if you take both Firetail and Kings is the biggest greenfield iron ore project to start up in Australia, and maybe the world,” FMG Solomon project director Simon Carter said.


One of the key elements to mine site infrastructure is power generation, but it is also one of the most costly inputs, especially as the majority of Australian mines are located in remote locations and simply hooking up to the grid is not an option.


Diesel generated power is a solution some operations use, but this can prove to be costly – both to the bottom line and to the environment.


Billing the Solomon Hub as a ‘next generation mine’, FMG moved to construct an innovative high voltage power transmission and distribution system; one reliable and strong enough to power two ore processing facilities, crushing hubs, kilometres of overland conveyors, a stock yard and train load-out facility.


FMG’s power infrastructure project manager Graham Martin explained providing power to the site was a complex project, costing $40 million and taking 11 months to complete.


Infrastructure developer Zinfra won the contract to design, supply, install, and construct high voltage overhead and underground transmission and distribution lines as well as three 132kV substations.


The tough working conditions on a greenfields site in the Pilbara which includes cyclones, poor soil conditions, soaring temperatures, and flooding are only exacerbated by the sheer scale of these types of projects.


“We’ve had bushfires, cyclones, storms, flooding, 50 degree days; it’s a very tough environment to work in, it takes a special kind,” Zinfra senior construction manager Tony Stewart said.


Supplying power to the site involved amongst other tasks, installing 177 poles, 54 kilometres of conductor, and laying 10 kilometres of underground cable.


Zinfra explained building flexibility into its plans was critical, especially as the mine’s scope of works continued to change throughout the roll-out phase.


Mine sites cannot afford to have power unexpectedly go down, interruptions to power supply directly impact a mine’s output and productivity, so unsurprisingly the biggest challenges Zinfra faced was ensuring its system was tough enough to withstand the heavy demands of a 24/7 operation and maximise the reliability of the network.


FMG identified Solomon has iron ore resource reserves of more than three billion tonnes, giving the operation a life of about 20 years, and with a ramp up guideline of achieving zero to 60 million tonnes per annum in less than two years from breaking ground, infrastructure reliability is going to be imperative.


Former Zinfra Group managing director Tony Beach said to deliver the project the company’s Solomon workforce peaked at about 80 people.    


“Our people and contractors had to work through the extreme nature of the project by keeping focussed and looking after each other,” Beach said.


Zinfra’s power project was key for FMG to achieve its milestones, including delivering power to the train load out enabling FMG to deliver early ore in December, Stewart explained.


Fortescue also enlisted an innovative hybrid approach to powering its Solomon Hub, signing a deal with GE Energy in 2011 for dual fuel aeroderivative gas turbine packages.


FMG’s director of development, Peter Meurs, has previously stated the miner needed "to rapidly develop our Solomon Hub and enable secure, low-cost production of iron ore for years to come, so we required a reliable and efficient power plant, GE was able to develop a fast track solution which met these demanding requirements for the Hub".


The turbines will start out fully diesel operated, but will later convert to gas when pipelines are available.


"These turbines have a unique capacity, as they can run on diesel and then convert to gas without needing a water injector to manage carbon emissions," GE Energy's sales director for power generation, Steve Graham has previously stated.


The LM6000s are known as aeroderivative as the gas turbines were originally developed for aircraft engine technology.


The dry, low emissions turbines reportedly have a reliability rate of nearly 99 per cent, and are able to achieve full generating capacity within only ten minutes. 


A key aspect of the turbines is that "it allows for continual development, so the operator can build out their power supply as demand grows at the site," Graham explained.