Further north on the site the pungent smell of smouldering coal filled the air as we stood above a coal extraction area. Yet more dumpers scurried by. Like ants. Busy busy.

The objective of this operation is to sell coal extracted on the site. Our Solid Energy host made sure we understood that, guiding us to the coal-processing, storage and load-out facility, rounding off nicely the Rotowaro site visit.

Each stockpile contains approx 5-6000m3 waiting to be conveyored directly to (or blended with another heap) to a hopper for loading onto rail-wagons.
The coal is discharged from the large hopper (located on the left of this photo). It holds approx 8000 tonne processed coal and one wagon (approx 19 tonne) can be filled every 25-30 seconds.


On April 23, a bus load of 18-20 hardy souls departed from the north Auckland Branch to meet 35 or so of their southern colleagues from Waikato/Bay of Plenty Branch for a top day out.

It had been several years since the IOQ had held a trip to Solid Energy’s Rotowaro Coal Mine in Huntly.

Despite being the Saturday of a 3-day Anzac weekend, many were keen to observe first-hand large equipment working in the open-cast coal operations. None was disappointed.
Henry Walker-Eltin are the operators at Solid Energy and utilise a fleet of diggers and dumpers, some of considerable size!

A Komatsu PC4000 Excavator loads overburden onto Komatsu 730E Hauler

Komatsu PC4000 Excavator stats:
* Made in Germany
* Operating weight – 380 tonne
* Engine – Cummins QSK 60. 16 cylinders in V configuration (60 litre)
* Flywheel HP (SAE) – 1875 (1400kw) / 1800 rpm
* Bucket Capacity Range – 16-28 m3 (This one fitted with 22m3 bucket)
* Hydraulic system – 4 x variable piston pumps
* Max oil flow – 4140 litres/min
* Max oil pressure – 310 kg/cm2 (4495 psi)
* Track shoe width 1500mm
* Fuel tank – 6400 litres
* Hydraulic tank – 3900 litres
* Boom length – 9.75 m
* Stick length – 4.5 m
* Estimated production – 2260 m3/hour

Equally impressive were the 730E Haul Trucks. Several scooting back and forward carting overburden to the dump site approx 800m away.

Komatsu 730E Haul Truck Statistics:
* Made in USA (ex Dresser Haulpak factory)
* Empty Vehicle weight – 138 tonne
* Gross vehicle weight – 324 tonne
* Hauling Capacity – 186 tonne
* Heaped capacity (2:1) – 111 m3
* Engine – Cummins K2000 16 cylinder in V configuration (50.3 litre)
* Gross HP – 2000 (1492kw) / 1900rpm
* Flywheel HP – 1860 (1388kw) / 1900rpm
* Max speed – 55.7 kph
* Turning radius – 14m
* Tyres – 6 x 37.00-R57
Fuel tank – 3217 litres

A similar arrangement operated in another area in the Rotawaro site approx 1km away. A clean loading area is considered important – Note the “small” dozer in the photo below – cleaned up the site as each full dumper left, to minimise risk of punctures.


En route from the Solid Energy coal scene it was appropriate to squeeze in a few minutes to take in Stevenson Huntly Quarry.

This whirlwind tour around their Huntly Quarry was conducted by former employee, turned OSH Inspector, again turned quarryman, Pat Wallbank. Wow that was a surprise for a few!

And on a midday Saturday blokes were there working that crusher overtime getting more stones on the ground ready for delivery to the new Hampton Downs prison site. Thanks Pat.


If ever you wanted to see a DEEP quarry, ask Terry Takiari, Quarry Manager Perry Aggregates Waipa Quarry, located just 2km south-west of Ngaruawahia.

Hemmed in by DOC (Department of Conservation) land to the west of the site, and unable to extract to the north – several substantial slips prevent extraction here, Perry Aggregates wait for the resource consents to be finalised so they can develop to the south.

Meanwhile managing extraction from a VERY narrow hole well below sea-level is Perry’s Terry’s fate. But he no complain. And he and his staff welcomed 50 or so very hungry boys and girls to lunch.

There are a good number of sponsors to thank for the day’s outing, one of the main ones being Eagle Equipment, part of the Porter Group of Companies.

In addition to serving mouth-watering BBQ sausages and steak displayed their new Hyundai 770-7 front-end wheel loader for the lads to “ooh” and “aah” at.

When Warwick Leach asked the troops for a group photo, we figured it a good chance to again thank the sponsors for showing off their new Hyundai excavator a bright yellow shiny machine contrasting the hard working front-end loaders of the regular Perry fleet.

Many thanks to all concerned for a GREAT day out.

Report from Murray Discombe.