The New South Wales Department of Primary Industries issued a safety alert following the latest incident in which a load-haul-dump (LHD) operator underground noticed an oil mist coming from within the engine compartment.
Attempts to shut down the diesel engine system were not successful and the engine would not shut down, even when the diesel fuel was shut off.
The DPI said the engine continued to run on atomised oil and revved higher when the fuel was switched off, with large amounts of smoke being emitted.
Eventually the CO2 extinguisher located on the LHD was used at the air intake to stop the diesel engine, as per the site training on emergency shutdown of diesel equipment.
The DPI’s investigation found that the steering pump output hose on the LHD failed by developing a hole approximately 5mm wide. This hole atomised the hydraulic oil creating a pressurised mist in the engine compartment and torque converter area.
Hydraulic oil covered the engine and centre drive shaft compartment saturating the air filter and intake flame trap.
The mine has scheduled the fitting of original equipment manufacturers’ approved engineering shutdown systems when available.
The DPI said the incident highlights the need for all explosion-protected diesel engines to be fitted with an emergency shutdown system.
Following a similar incident last year, the DPI’s senior inspector of mechanical engineering issued a June 2005 notice (Section 63A) requiring all such vehicles operating in significant-risk methane areas to be fitted with an approved emergency shutdown system by February 20, 2006. Furthermore, that these vehicles be fitted with an approved emergency shutdown system by February 20, 2007.
The DPI said mines should aim to install approved emergency shutdown systems as soon as practicable.
All mines were advised to check the integrity of pressurised hydraulic or fuel lines in the vicinity of the engine compartment on a periodic basis and to replace worn fuel and hydraulic hoses if located near the engine compartment.
