by Kyle Molyneux | Fri 03 Apr 2020
New Liebherr for Premier Coal
Premier Coal, a large mining company based in Western Australia, has recently taken delivery of a brand new Liebherr R 9400 hydraulic excavator, complete with mighty 24m3 bucket and high-vis detailing. Replacing an R 994B on site, the new machine joins another R 944B, R 995 and a pair of R 996Bs for a seriously impressive line up.Premier Coal mines around 4m tonnes of coal per year, and the company’s new Liebherr R 9400 should play a big part in that going forwards. With an operating weight of around 350 tonnes, the excavator runs a Cummins QSK50 engine developing 1,250kW at 1,800rpm.
Posting details of Premier Coal’s machine on Facebook, Liebherr Mining made an interesting comment about why its excavator's boom cylinders are mounted upside down compared to those of smaller machines. Although “there is no correct or bad installation of the hoist cylinders, the final installation is mainly driven by two things: the structural life of the main frame and the hydraulic connections. Installing the cylinders with the barrel on the boom side gives more clearance for the chassis design. The chassis design is very important to achieve the structural lifetime and fatigue life which are very high in the mining industry as we consider a day cycle of approx. 22.5 working hours.”
When it comes to the hydraulic connection, “The bigger the cylinders, the bigger the oil volume needed to achieve a correct speed. Having the cylinder barrels on the boom side makes the hydraulic connection much easier as the hoses can run over the boom top before coming down to the cylinders. If you had the cylinders installed the other way, you would have to find a way for the hoses through the main frame and that’s nearly impossible for big cylinders because of space problems. If you have a look on our competition, you will notice that everybody is installing the hoist cylinders with the barrel on the boom side.”
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