Quarry Magazine finds out why major limestone producer Graymont purchased two Kobelco SK500XD excavators.

Lime and limestone are among some of the oldest and most vital materials used by humans. The materials were the literal building blocks for ancient pyramids, temples, and roads.

Nowadays, lime is used in road stabilisation, asphalt, water treatment, steel making and metalliferous processing. Limestone is utilised as a mineral filler in stockfeed, for cropping and pasture improvement and flue gas desulphurisation, among many other applications.

Canadian-owned company Graymont is a world leader producing lime and limestone solutions critical for a decarbonised world. Graymont’s Australian operations are located on the east coast and Tasmania. This network is supported by its operations in New Zealand, Malaysia and the Philippines. Graymont also has a significant presence in the North American lime and limestone market.

Kobelco Customer Graymont Sk500Xd

While limestone is not particularly abrasive, Graymont wanted to update and upgrade its excavators. Damian Power, site manager at Graymont’s Attunga plant, told Quarry this is why the company purchased two Kobelco SK500XD diggers.

“We were in the market for a good, reliable machine that was well supported by the dealer,” he said.

The SK500XD ticked all the boxes – it is ergonomic, has low noise output and is economical to run.

Damian Power, site manager at Graymont’s Attunga plant

Kobelco designed the SK500XD for extreme durability. It is engineered to operate in the harshest conditions worldwide, making it ideally suited for a variety of applications in Australia, such as quarry excavation.

Weighing in at 52,200 kg, the SK500XD is the heaviest machine in its class. It is purpose-built with a robust machine body and substantial additional reinforcements to all key areas of stress and wear across the boom, arm, underbody, and undercarriage.

Kobelco Customer Graymont Sk500Xd

It features a specially adapted heavy-duty boom and arm set to handle harsh quarrying conditions. It comes with factory-fitted, triple-plated, hardened steel applied to all key structural sections, including the boom-to-arm connection, the boom centre, and the end of the arm—providing a high level of durability and longevity to the attachment structures.

 A specially designed full-length rock guard is installed on the inside of the dipper arm, on top of additional steel plating. A quadruple track guide frame allows it to operate reliably in harsh and rocky conditions, while reinforced heavy-duty 600mm triple grouser shoes make easy work of rough terrain.

Kobelco has also worked to improve the durability of the track links. The idler frame has received substantial double reinforcement plating inside and out, preventing premature wear of this key structure.

Power said one of the key benefits of the machine was its fuel efficiency.

“It has one of the lowest fuel burns of all the diggers we looked at,” he said.

“That adds up. It means we’re spending less on fuel, and we’re emitting less carbon, which is becoming even more important.”

Fuel efficiency is a key part of the SK500XD’s design. It delivers an average fuel consumption under 30 L/hr in typical Australian heavy digging conditions.

Kobelco Customer Graymont Sk500Xd

Part of this is due to a new boom-to-arm regeneration system, which more efficiently controls hydraulic fluid flow and delivers a significant reduction of in-line resistance and pressure loss. As the need for fluid to be forced from the pump is reduced, the engine and hydraulic workload will be less, which means higher fuel savings.

Three work modes allow the operator to select the best mode for the job at hand – heavy-duty and standard work options, and an ECO-mode that automatically optimises digging efficiency, delivering a 13 per cent decrease in fuel consumption.

Power said the machine came highly recommended by others in the local industry.

“We did our homework and looked at the excavators that were available. A major Tamworth business had given them a go and were happy with them,” he said.

Gato Sales and Repairs, one of the dealers that supplied the machines, were great to work with too. They were always available on the phone if we needed something.”

Ease of serviceability was a key priority for Kobelco engineers. The SK500XD has extended fluid service intervals, easily accessible remote-mounted fluid filters, and modern engine emissions, which are simple to service and don’t require AdBlue.

Kobelco’s reliable fluid filtration systems improve hydraulic performance for the life of the machine, reducing the risk of mechanical trouble and enhancing the machine’s longevity. The intelligent hydraulic system further enhances reliability, notifying the operator if filter performance is compromised, ensuring reduced downtime while maximising the machine’s value.

The addition of a new hydraulically driven cooling package with independently driven fans for the hydraulic cooler, engine radiator and intercooler, not only improves fuel economy but also reduces engine noise while providing optimal oil temperature control—for increased reliability and performance in demanding high ambient temperature environments.

However, the highlight of the machines for Power is its ergonomic factor.

“The cabin is spacious and feels comfortable to sit in for extended periods of time. It’s got a large front window and a lot of noise dampening inside,” he said.

“It’s also got a heated and air-cushioned suspension seat, protecting the operator from vibration, with climate control to keep you cool on hot days.”

Also inside the cabin is a colour LCD multi-display screen, that shows all the important information, including fuel consumption and maintenance intervals, as well as an integrated rear-view camera.

Power said the Kobelco excavators, which have been used across the quarry, have been fantastic.

“They’re reliable machines. We’re very happy with them and looking forward to continue seeing these great results.”

Kobelco Customer Graymont Sk500Xd