Southern Pacific Sands operates one of the largest and most diverse sand mines in South East Queensland at Ningi, east of Caboolture. The mine has in the past operated equipment for long hours, with some machines approaching 20,000 hours, but the appointment of Mick Dickinson as Mine Manager 18 months ago has seen a change in philosophy.

The recent purchase of a 34-tonne hydraulic excavator involved competitive tendering, and Mick looked for a warranty to cover the 8000 hours that he planned to operate the machine before replacing it.

A Doosan DX340LC excavator performed well in competitive trials, and the pricing and support package that Daewoo / Doosan Construction Equipment salesman Drago Leskarac put together clinched the deal.

The DX340LC excavator is used to load 25-tonne dump trucks that take sand to the screening plants and, with a larger mud bucket than its predecessor (2.4 m3 vs. 2.0 m3) and greater digging force, it can load the dump trucks in four passes rather than six. The improved cycle times mean that more trucks can be put on a circuit to improve productivity. Larger dump trucks are being considered for the future.

The hardest job for the DX340LC excavator is accessing underwater sand, which supervisor Steve Powell describes as “hard as concrete.” The excavator works at full reach to dig a bench, then walks onto the bench to dig under water and cast the sand onto the upper level. Automatic lubrication was specified to protect the dipper arm and bucket joints during underwater work.

The Doosan excavator uses a marginally smaller bucket for this, though larger than that used by its predecessor (1.55 m3 vs. 1.45 m3). However, it does not have the same overheating problems in this work and can maintain productivity.

Operator David Adams has been impressed by the smooth feel of the controls, the roominess of the cab and the space and layout of the engine bay for servicing.

Southern Pacific Sands plans to add a second Doosan DX340LC excavator to its fleet in the near future