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Rio Tinto first began to prospect for coal in the Tarong area near Toowoomba, Australia, in the late 1960s. Drilling subsequently confirmed a substantial deposit, sufficient to warrant the construction of a power station. Development works for the resulting mine started in 1978, coinciding with the Queensland Government starting work on an adjacent electric generation plant. As far as the muck-shifting community is concerned, 1982 was a key year in this long-term project, as many convoys of heavy haulage trucks delivered the components of a 3500-tonne Bucyrus Erie 1370W dragline from the port of Brisbane to the new Meandu Mine.

 

 

This giant among earthmoving machinery was, and still is, responsible for shifting the overburden on site. A 47-cubic-metre bucket is swung at the end of its 100m-long boom. During the past 30 years, the 1370W dragline – named Hannibal – has run 24/7, shifting 60,000 cubic metres every 12-hour shift, only stopping for major maintenance works. Meandu Mine was officially commissioned in 1983 and began to supply coal the following year to the recently completed Tarong Power Station, via a 1.5km conveyor belt. As more generators were brought on stream, coal production was further increased. 

 

Interestingly, Hannibal has played a key role in the development of giant dragline technologies, as starting in the late 1990s it was a test bed for an automated dragline dump cycle system. The computer power of the time managed to coordinate the drag, hoist and slew drives, resulting in a system capable of automatically moving the bucket, after the operator had filled it, to a specified dump site and then back into position for the next cycle. 

 

Year after year, Hannibal kept on moving muck. Even more coal was required, as a second power station, Tarong North, was completed in 2003. In a typical year, the Meandu Mine will supply the power stations with up to seven million tonnes of coal. 

 

 

I was fortunate enough to visit the site just before Hannibal received its overhaul. The scale of the workings on the 12,000-acre site is almost unbelievable. The haul roads are wide enough so that two Cat 789C dump trucks – the loaded one grosses out around 320 tonnes – can pass each other with ease. I assumed that the 6in-diameter pipe running to the giant dragline was part of the dust suppression system, but it wasn’t. It was an electrical cable powering the walking dragline. A giant Cat D11 dozer is used as a utility vehicle, to clear up any spillage from the bucket!

 

My guide for the day was Jim Young, who was originally part of the crew that spent 18 months building up the dragline in the early 1980s. He is currently the mine’s asset manager and was responsible for the site’s latest significant acquisition, a Hitachi EX8000-6. This 800-tonne class hydraulic excavator arrived on the back of a fleet of trucks in the middle of this year. Named
Atlas, it started work in September 2013 and is believed to be the only backhoe version of the EX8000-6 produced to date.

 

Arriving close to the dragline, Jim made a radio call to the operator asking for permission to come aboard. Hannibal never stopped working, but steps were lowered and we climbed aboard. On entering the bowels of the beast, the noise of the cooling fans up in the roof was deafening. Walking up through the equivalent of a 10-storey building, the first thing to catch the eye was the huge winding drum. This is used to lift the bucket and is powered by a pair of 1000hp electric motors. A range of smaller electric motors is used to lift the massive boom, move the feet three metres at a time and perform all the other functions of a walking dragline.

 

 

From here it was through a sound-proof door into the ‘crib room’, a crew rest area directly behind the cab. Through another door and it was into the cab where Rod Evans was at the controls. Rod has been one of Hannibal’s operators for the past 21 years. Sitting in what looked like a very comfortable chair, with all the controls he needs positioned on the arms, he was totally focused on the job in hand – to excavate overburden to a depth of 27 metres, to expose a seam of coal 18 metres deep. After witnessing a few cycles we left Rod to it. As in any workplace, time is money, but in this machine we are talking about figures with lots of zeros at the end. 

THE FUTURE 

 

When the mine first opened in the early 1980s, it was estimated that there were sufficient coal reserves to last 25 years. However, the latest projections indicate that there are sufficient reserves to feed the power stations until around 2025 to 2030.

 

The Bucyrus Erie 1370W is now 30 years old, but with up to a couple of decades more work ahead of it, it was time for a rethink. You don’t pop down to your local dealer to order a replacement 3500-tonne dragline, but it is worth spending a few dollars – estimated at A$53million – to overhaul it!

Earlier this year Hannibal completed a three-day, 5.4km walk to an overhaul area on site at an average speed of 250 metres an hour. The bucket, rigging and ropes were removed and responsibility for the dragline was handed over to Queensland contractor G&S Engineering Services. They took four months and employed 160 people to perform the work.

 

It is now back in pit, shifting 120,000 cubic metres of overburden every 24 hours.