As part of environmental compliance requirements, mine sites have noise specifications for mobile machinery, including in service (existing machines) and delivered (new machines) specifications. The noise specifications for this mine site were 125 dB (linear) for existing machines and 123 dB (linear) for new machines. The Liebherr 996 was an old machine with over 60 thousand hours. It had been previously fitted with a complete sound kit, and had accessibility and cooling issues.
Traditional “one-type-fits-all’ attenuation solutions on excavators can include replacement or modifications to the mufflers, radiator attenuators, oil cooler attenuators and louvre panels. The additional equipment often causes visual obstructions, accessibility issues and maintenance problems and can cost in excess of $500K. The increase in engine back pressure further impacts performance as the vehicle has a high potential to overheat.