Caterpillar 322CL excavator with spot cultivator - Operator Review

Leaving the Tasman Highway at Springfield heading south, a few kilometres west of Scottsdale, the narrow bitumen lane quickly gave way to a well-maintained gravel road.

In the distance, clouds form a blanket around the imposing Mt Barrow, also known as ‘The Diddlum’ to locals. As the track winds its way further up into the hills, the tall timbers close in.

It is here in The Diddlum that men used to carve a meagre existence from the forest for their families. Even today, shoe-holes created by early tree fellers to locate their ‘shoes’, which were essentially long timber planks to stand on to cut down the trees, can be seen on the huge tree stumps.

Even in the 1950s, the skills of an axeman meant a good living.

“If you could fall more than someone else, well, you got more money,” an old feller explained. “It was as simple as that.”

“And times were tough, you know,” he reflected. “In the early ‘50s, if you could earn eight or ten pounds a day falling, that was good money compared to an average wage of about two pounds a day.”

Today, the steady beat of the tree feller’s axe echoing down the valley has been replaced by the steady humming of machines taking over the jobs of these axemen.

Spot cultivator

As the forest cleared, the yellow arm of a Caterpillar 322CL excavator fitted with a spot cultivator attachment came into view. Robbie Viney is a workshop foreman for Scottsdale based contractor, Kelly Gerke, and oversees the building and fitting of these spot cultivators on to the company’s Cat fleet.

Currently, there are 12 of these machines working around the state.

“This spot cultivator you see here is part of a continual evolution that started some six years ago,” Viney explained. “In that time, we’ve redesigned it from virtually the ground up.”

He added the design of the spot cultivator very much depended on the conditions operators are working in.

“The earlier versions worked well in soft soil, but as we realised their potential and expanded their utilisation, the terrain and vegetation changed,” he said.

“We started to encounter rockier outcrops so we needed to beef them up. It wasn’t just a case of adding an extra bracket here or there, as this would affect the spot cultivators' operation; nor could we simply use thicker steel, as this would add considerable weight which in turn meant a larger machine might be required.

“We are constantly monitoring how they operate in terms of the task at hand and service life.”

The spot cultivator is used to build a mound for new trees to be planted in. At the same time it builds the mound, it also forms a moat type basin to hold water, which is what makes it so useful.

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Versatile and sustainable

“To fully understand the significance of these spot cultivators, it’s probably worth understanding how revegetation preparation was carried out before these spot cultivators came on the scene,” Viney said.

“In most cases, we would use what’s known as a mound plough towed behind a Caterpillar D6 or D7 dozer. Using that method was not as simple.

“Firstly, the dozer would have to clear the bush by removing all the stumps and left over limbs. It would then make a second pass over the ground with a stick rake pushing the stumps it had cleared into windrows.

“The dozer then had to make a third pass with the plough and in really steep country, the dozer and plough simply couldn’t operate.

“Because ploughing typically leaves long furrows, during extended periods of rain the volume of water could overflow the furrows which in turn causes erosion even though the hills were contour ploughed,” Viney said.

“You can imagine as each furrow emptied into the one below, the deterioration just grows.

“So not only have we improved the efficiency of our operation with the spot cultivators, but we have also realised a considerable number of environmental benefits,” Viney said.

Almost as if on cue, the 22-tonne Caterpillar excavator working away in the background lifted itself over a tree stump and continued building mounds.

“With the excavator, all the vegetation is left intact which greatly assists the young gums as they start to grow,” Viney said. “The excavators can also work in steep country and do everything in one pass.”

Cat 322CL to the rescue

As the spot cultivator evolutionises, the company was faced with the challenge of finding the right machine to operate it.

“We tried a smaller 20-tonne excavator but with limited success,” Viney said.

“Then we tried the larger 25-tonne machine, but we found the 22-tonner to be the most effective.

“They’re very quick with their hydraulics, and extremely efficient to run for their size. We started with the 322B machines and now have the 322CL models.”

Operator Tim Knight has been driving earthmoving machines for a long time and said the Caterpillar 322CL was the best he’s been in so far.

“From an operator’s point of view, these Cat 22-tonners are extremely smooth and quiet,” Knight said.

“The redesign Caterpillar made to the interior really maximised the workspace. The right hand wall and console provides easy access to the switches, dials and controls.

“The fully automatic climate control adjusts temperature and flow and determines which air outlet is best in each situation. And the new seat greatly reduces operator fatigue.”

The 322CL is powered by CAT’s 3126B ATAAC HEUI fuel system giving 168hp. Extended maintenance intervals mean the machine can work for longer in between servicing.

The hydraulic cylinder snubbers at the rod-end of the boom cylinders and at both ends of the stick cylinder cushion shocks, reduce sound and increase cylinder life, keeping the machine working for longer.

The boom and stick regeneration circuit increases efficiency and reduces cycle times for higher productivity and lower operating costs.

Servicing points are easily accessible at ground level, allowing critical maintenance to be done quickly and efficiently.

Viney also sang the praises of Caterpillar’s aftersales service and said that was one of the main reasons the company owns so many Cat machines in its fleet, alongside the 37 to 48 months warranty package, spare parts availability and overall reliability.

Each of the 322CL excavators fitted with spot cultivators tills approximately two hectares per shift.

“This type of work is really hard on the track gear and final drives of the machines, mostly because excavators are not designed to walk up and down paddocks like a tractor,” Viney said.

“An excavator is most efficient when it is sitting in one place loading or digging. That’s why we work the 322CLs between 5000 to 6000 hours with the spot cultivator, then we attach a log grab and put it at the landing to load our trucks.

“It just sits there loading trucks all day and when it comes time to change the machine over, the wear and tear is as it should be for a machine of its age and engine hours.”

In fact, word about the unique but effective machine combination of excavator and spot cultivator has spread far and wide and forestry contractors throughout Australia are reportedly expressing interest in rolling it out in their respective operations.