Putting production figures of the two 550-tonne excavators on site against each other provides for an interesting comparison. The EX5500 performed to NRW’s planned dig rates. However, according to Shaun Lucas, the EX5600 excavator, matched with the EH4000 trucks, provided "about 30% in end-yield on top of what the 5500 does".
In this video: Learn about the productivity gains the Hitachi fleet has brought to NRW's operation. (1min, 43s).
Sean Lucas attributes the increase in performance to the significant increase in the horse power - which translates into productivity - of the EX5600. The EX5600 is powered by two Cummins diesels delivering a total of 2238 kilowatts of usable power - up from the 2014 kilowatts of the EX5500. The improvements are appreciated and acknowledged at NRW: "What Hitachi have done with the 5600 as opposed to what the 5500 was is incredible. They have really listened to what to operations need and they have made those changes".
The other half of the Hitachi equipment equation at Middlemount - the AC-drive dump trucks - are also playing their part, especially the 220-tonne payload EH4000s. But the quick turnaround is having some unexpected impacts. Whereas in the past the truck operators could look forward to a bit of downtime during the loading cycle, but, as Shaun Lucas tells it: "...(the drivers) get their book open and find their line and it’s bang and they’re off again. Three buckets in an Hitachi 4000 and it’s gone".
On the next page, we look at the result of having Hitachi machinery.
