The shovel’s upper and lower slew ring bearing mounting faces, shear ledges and track frames all required machining as a result of wear and tear to restore the required flatness and surface finish, as part of a planned major maintenance overhaul. The work had to be completed in the shortest possible timescale, to minimise shovel downtime and get it back in operation.

The demanding surface tolerances required would normally be associated with workshop machining, but transporting the 1200 tonne shovel off-site would have involved substantial cost and logistical issues, as well as considerable added time. Instead Furmanite, known for its specialist expertise and experience in machining slew rings and mounting surfaces in-situ to workshop tolerances, was called in by P&H MinePro Services to undertake the work on site, representing significant time and therefore cost savings.

Furmanite technicians undertook a laser survey of the 4.6 metre diameter slew ring bearing mounting surfaces to check both flatness and alignment and establish the exact extent of the machining required.

The machining was then undertaken using Furmanite’s circular self-levelling machine (CSLM) technology, which is capable of machining circular structures up to 24 metres diameter in-situ, to extremely high levels of accuracy. A wheel-mounted milling box/cutter rolls on the face being machined as it rotates round a central pivoting system, using a datum ring mounted around the central pivot point as a reference, with electronic probe sensors continuously adjusting the height of the milling head. A final machining tolerance of ± 0.008 inches was achieved, with a surface finish equal to or better than Ra 1.6µm.

Additionally, the 5 metre long shear ledges and track frames were also machined on the horizontal and vertical face, using Furmanite’s X-Y milling machines to an actual tolerance of ± 0.004 inches, again with a surface finish equal to or better than Ra 1.6µ.

“Our ability to undertake highly accurate machining on such large scales on-site is increasingly being called on, particularly in the mining industry where the size of the equipment means it is highly beneficial to be able to undertake any necessary work to high quality standards in-situ, both to minimise downtime and avoid added logistical issues and expenses,” comments Furmanite east region sales manager Graeme Berry. “Our on-site machining expertise is just one of a range of services we offer to help mining industry operators maximise asset uptime.”

The P&H 4100 electric rope shovel weighs a total of some 1200 tonnes, and features a 43m3 (57 cyd) dipper and 77 tonnes (85 ton) dipper payload, enabling three pass loading of 218 tonne (240 ton) haul trucks, plus various ease-of-maintenance features including modular components.

For further press information please contact:

Sarah Manwaring-White, Keep in Touch Ltd,
Tel: +44 (0)1451 844 488  
Email: sarah_mw@keepintouch.co.uk

Issued on behalf of Furmanite Australia
www.furmanite.com