Quarrying & Mining Magazine
Machinery

Monster for Huntly Coal Mine

A contract extension at the Rotowaro coal mine has seen Stevenson Mining buy a brand new, 400 tonne Liebherr excavator to provide some serious muscle at the mine. BY MARY BELL.

Stevenson Mining’s EHS and workshop manager Scott Tanner says the excavator would take about three weeks to be assembled; “about a week for the big components and another two for all the bits and bobs and pieces you don’t see.”
Stevenson Mining’s EHS and workshop manager Scott Tanner says the excavator would take about three weeks to be assembled; “about a week for the big components and another two for all the bits and bobs and pieces you don’t see.”

A massive new Liebherr excavator has just arrived in the country and will soon be hard at work digging coal at Rotowaro mine for Stevenson Mining.

There are only a handful of machines of this size in New Zealand, and this one will be the second Stevensons will have working at the mine in Waikato.

However, before a single hour could be logged, the 400 tonne monster had to be transported from Auckland’s port to the mine in Huntly and then be assembled – no small feat for a machine of this size.

Stevensons has had its contract at Rotowaro extended until the end of 2018, enabling the company to justify the multi-million dollar purchase. The brand new monster digger had been sitting on the dock in Australia as the deal that got it there from the manufacturer had fallen through. This meant Stevensons was able to get the machine much more quickly than you would normally expect.

The roll-on/roll-off ship carrying the Liebherr arrived in Auckland in late August. The machine was in 20 different pieces and packages, all loaded on Mafi trailers (a cargo trailer the same shape as the base of a container, with a gooseneck and tractor unit). Once off the boat the team from Tranzcarr Heavy Haulage were waiting to load them onto a fleet of transporters to take them to the mine to be assembled.

The key loads, their weights and the transporters Tranzcarr used were as follows:

  • the upper carriage, weighing 45 tonnes, transported on four rows of eight;
  • central girder, 28 tonnes, three rows of eight;
  • side frames (left and right tracks), 59 tonnes each, loaded onto eight-axle Goldhofer platform trailers with ballasted tractor units (116 tonnes all up per trailer);
  • counterweight, 25 tonnes, transported on four rows of twin; and
  • gooseneck boom, 32 tonnes, seven axle trailer;
An eight-axle platform trailer is reversed under the gantry to be loaded with one of the Liebherr’s massive tracks, which weighs in at 59 tonnes.
An eight-axle platform trailer is reversed under the gantry to be loaded with one of the Liebherr’s massive tracks, which weighs in at 59 tonnes.

The rest of the overweights – the 20-tonne stick, 23-tonne powerpack, cab and cab elevation, and fuel and hydraulic tanks (which weigh less than 10 tonnes each) –travelled on six of Tranzcarr’s low loader transporters.

In addition to these loads there were multiple packs of between four and eight tonnes.

Tranzcarr loaded everything out of the port using its 200 tonne lift and lock gantry system. Once loaded, the various units took the 105 kilometre journey from the port to Stevenson’s yard at Rotowaro mine.

Tranzcarr’s Mike van Ravenstein says they were given an order of assembly so they knew which pieces needed to get to the mine first, and assembly began as soon as the parts of machine started to arrive.

At the port in Auckland the excavator’s 25 tonne counterweight is lowered onto a transporter using Transcarr’s lift and lock gantry system.
At the port in Auckland the excavator’s 25 tonne counterweight is lowered onto a transporter using Transcarr’s lift and lock gantry system.

At the mine Waikato Cranes unloaded the transporters as they arrived and stayed for the week to put the main components together. Q&M was on site to see the biggest lift, the upper carriage with cab lifted onto the undercarriage.

Stevenson Mining’s EHS and workshop manager Scott Tanner told the magazine that assembling the big components would take about a week, however, all the “bits and bobs and pieces you don’t see” will take another two weeks. “For example, the fire suppression system takes about a week to install.”

Supervising the assembly, and doing a lot of the hard work going by the sheer amount of grease and oil on his high-vis, was Harvey Appleton from Liebherr Australia.

Two cranes were used to lift the upper half of the machine onto the undercarriage.
Two cranes were used to lift the upper half of the machine onto the undercarriage.

The only piece that is missing is the bucket. The 24 cubic metre unit was still on the boat from Europe when the magazine went to print and is due in the country this month. Once it’s here the monster Liebherr will begin to work.

Scott says it will load half a million BCM per month, filling a 200 tonne dump truck with four bucketfuls, working two 10 hour shifts, five days a week.

Stevenson will train up a number of operators on the 400 tonner but will roster on the most efficient of these.

“We will put the guy in it who can swing it the fastest,” says Scott. “The machine is working from key on to key off so it takes a certain mentality to stay focused that whole time. The operator needs to be consistent throughout the whole day.”

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