Sunday 8th Dec, 2019

Gear from SEW China ticks all the boxes

By combining German design, Chinese manufacturing and local support, SEW-Eurodrive upgraded an Australian mine operator’s critical slewing-winch gearboxes.

After 29 years of operation, mining company Tronox needed to upgrade a major dredge at its mineral sand mine in Cataby, Western Australia.

The site’s dredge is core to Tronox’s entire process, dredging ore deposits, which are then run through a concentrator to produce a heavy mineral concentrate. The concentrate is processed at Tronox’s Kwinana pigment plant, altogether forming one of the world’s largest integrated titanium dioxide projects. If the dredge is taken offline for too long, all aspects of the operation would be unacceptably interrupted.

The existing gearboxes were inadequate for the new duty, with all gearing and some bearings requiring upgrades. As part of the upgrade, the dredge’s slewing winch gearboxes needed to deliver 30 per cent more slewing power.  Three gearboxes would be required for the upgrade, with two to be put into operation and the third kept as a spare unit.

Demanding constraints

As part of the search, Tronox engaged a consultant in China to investigate its market and source at least one of the gearboxes required. While there was a variety to choose from, few were able to meet the demanding constraints of high-end quality, appropriate cost, improved performance and mechanical fit. Ultimately, it was a trusted supplier, Inline Engineering Services, who proposed the solution.

Based on previous successful projects, Inline suggested SEW-Eurodrive, which was provided with the criteria of the project. Knowing the capabilities of its colleagues’ manufacturing site in China, SEW-Eurodrive’s Perth team devised a plan. Tronox also inspected the SEW-Eurodrive manufacturing plant in Tianjin, in addition to other Chinese gearbox suppliers, before making the decision to progress with SEW-Eurodrive’s offer.

Wayne Martin, WA State Manager, SEW-Eurodrive, explains his colleagues in China had the capability of designing and manufacturing gearboxes which met the demanding criteria.

The new gearboxes were supplied to Tronox by Inline Engineering Services, which also assisted with installation and commissioning. During this phase, and following the project’s completion, SEW-Eurodrive’s Perth office provided ongoing support. All parties needed to work together to achieve the desired outcome for the mine with minimal disruption during the upgrade.

To avoid time-consuming modifications to the dredge, the design team opted for a ‘drop-in’ solution. The replacement gearboxes replicated the external footprint of the original by matching all the critical dimensions, including bolt-hole patterns. Changes to mounting platforms, terminal connections, couplings and motors can often become expensive with refurbishments of this kind but weren’t required with this method.

While the external dimensions of the gearboxes were specifically designed to match the dredge, the internal design was a different matter. SEW-Eurodrive used its standard gears within the gearboxes, allowing the designers to achieve the desired 30 per cent increase in slewing power.

“This combination makes it so much easier for the client,” Mr Martin says, “Basically, you just take it to site, get a crane and drop it in.”

Quality assured

With the technical specifications and gearbox performance taken care of, attention turned to assuring Tronox of the high quality of materials and processes in the manufacturing facility. Due to its importance, the project team allocated a full month to this verification and qualification phase.

Bryan Brookes, SEW-Eurodrive’s Industrial Gears Product Manager, says that in addition to the standard material data reports that would normally accompany its gearboxes, SEW-Eurodrive provided additional details.

“These source documents were quite specific in nature, covering both material verification and manufacturing processes, including for the heat treatment stage,” he says.

“This was in addition to documents verifying dimensions and traditional parameters such as material load testing. There was no compromise when it came to the quality of the product coming from SEW China.”

Non-standard designs of this kind generally take a longer time to manufacture. However, Mr Brookes says in this case the process was fast-tracked and completed within standard timeframes. This was done to suit maintenance schedules at the mine, as the new gearboxes could only be installed during a major shutdown.

With the new gearboxes safely delivered to Australia, Tronox and Inline Engineering Services worked closely together, fitting new drums to the gearboxes and then mounting them onto the dredge.

The dredge-upgrade project took 12 months to complete, including the planning and design phases. Matthew Rein, Senior Mechanical Project Engineer at Tronox Northern Operations, says the project was successful.

“Tronox has rarely sourced equipment of this kind from China,” he says. “The reassurance of local support and representation from Inline Engineering Services and SEW-Eurodrive was an important factor in making the decision.”

“It all went well and according to plan,” he says. “We would do it again. We made cost savings, but without compromising quality.”