DEMM Engineering & Manufacturing
Bolting performance fundamental to Bishop crane refurbishment
Up in the rugged and remote highlands of Papua New Guinea, miners and contractors prize reliability and uptime in the machinery they deploy for vital production, construction and maintenance tasks.
Keeping such machinery in prime operating and safety condition was particularly important to Bishops when the company decided to refurbish a Liebherr All Terrain Crane LTM1090/2 deployed 770 metres above sea level in the misty jungles near Bulolo.
The machine – new examples of which are worth more than NZD1.8 million – had completed five years of service at the Hidden Valley gold and silver mine operated by Morobe Mining joint venture between Harmony Gold of South Africa and Newcrest Mining of Australia.
Bishops Company Principal Mark Bishop decided that, after five years of continuous service at the mine, the crane would benefit from a rebuild to as-new condition, so he swapped it with his 100t Liebherr and shipped the previous crane back to his workshop and machine shop facility in Port Moresby, about 250 km away.
“Replacement of such an important part of the crane as its slew ring was fundamental to his rebuild strategy, for which he required top quality, fast, efficient and safe professional bolting technology,” said Enerpac PNG Manager Pat Molloy, who works in partnership with Enerpac distributor Bishops.
The tools selected for the task including the Enerpac S1500 torque wrench, supplied by Bishops Port Moresby, from the same Enerpac professional bolting ranges used globally on some of the world’s biggest building and infrastructure projects.
RIGID STEEL ENERPAC
The powerful, safe and non-impact rigid steel torque wrench was actuated by an Enerpac ZU4 torque wrench pump, which features Z-Class high-efficiency pump design; higher oil flow and bypass pressure, cooler running and requires 18 percent less current draw than comparable pumps. The swiftly operating and ‘easy-to-use’ ZU4208BE-Q pump features a powerful 1.7 hp universal electric motor that provides a high power-to-weight ratio and excellent low-voltage operating characteristics.
This performance, coupled with the power of the 2.7kg S1500 (which, at 1898Nm, is the baby of Enerpac’s Square drive range extending up to 34.079Nm) easily loosens bolts that have become frozen in place over time. “Then the same pump and tool combination rapidly and safely retightens slew ring nuts to the exact and even torque ratings required for ongoing reliability and safety,” says Molloy.
All Enerpac professional bolting tools – including S-Series Square Drive and W-Series Low Profile Hexagon torque wrenches – are precision calibrated and rated for quality, performance traceability across a diverse range of bolting tasks, including joint separation, controlled tightening and joint assembly, ensuring joint integrity across the spectrum of bolting work flow.
“The Enerpac gear was ideal for this job, because it provides speed and accuracy as well as traceable bolt loads,” said Molloy. “The large nut rotation per wrench cycle and rapid return stroke of the S-Series makes the job particularly efficient,” he said.
Operated by Bishops in-house staff trained to world standards, the pump and wrench combination was also used as required in the refurbishment of the crane’s entire drive train, including transmission, brakes and steering rebuild and fitting of new suspension on the carrier. All hydraulic components have been refurbished, with new hoses throughout. Electronics, electrical and lighting have been upgraded or replaced. The machine has also had a cosmetic refurbishment, being refinished in yellow and grey to match the rest of Bishop’s Liebherr. PNG technicians trained by Liebherr, John Laho and Miu Hao, have been the driving force behind the task.
Bishop’s crane fleet includes 14 units, extending from his flagship LTM1200 / 200t All Terrain down to 20T Terex Franna Mobiles. Bishops Equipment Hire played a major role in the construction phase of the Exxon Mobil gas project in Port Moresby.