CAT 793D Sound Suppression Exhaust System Upgrade

Mining operations are complex sites that involve many different activities that produce different types of noise. These types of noise vary at different times of the day, usually based on the type and location of the mining operation.

Mining operations typically involve a mobile fleet, which includes dump- trucks, graders, dozers and large earth moving equipment, road and rail activity and blasting. Mines typically operate 24 hours a day, seven days a week, and it’s due to this fact that the government has introduced polices and regulations to help manage this noise. These policies and regulations such as ‘NSW Environment Protection Authority’ and ‘Industrial Noise Policy’ balance the need for industrial activity with the need to minimize noise impacts on the community.

The Hunter Valley is home to more than 630,000 people living in a mix of rural communities and urban centers. This region is home to a diverse economy with significant industries such as coal mining, power generation and agriculture. The mines that begin near the eastern edge of the basin are spread along the Hunter Valley from Newcastle in the south to Muswellbrook in the north. Many of these mines are open-cut, which produce high levels of noise that irritate nearby residents.

Aletek has established that exhaust noise is the most dominant contributor to the overall Sound Power Level rating of mining equipment. Until exhaust noise is sufficiently attenuated solutions such as low- noise radiator fans or splitter packages for radiator and engine panels, do not provide any practical or beneficial reduction in the Sound Power Level rating of the machine. Therefore, to design a cost-effective solution it is always advisable to adopt a staged approach with the identification of contribution of each noise source (radiator fan, engine and exhaust). For this purpose, Aletek either relies on its extensive database of noise testing results collected over the years or carries out noise measurements on the actual (or similar) machine under investigation. This process allows Aletek to design highly effective sound suppression solutions by targeting specific requirements.

Aletek submitted a proposal to provide a large mining client in the Hunter Valley with a sound attenuation package on their CAT 793D XQ mobile fleet. Our proposal was based on a sound attenuation package designed to achieve a sound power target of 123dB LW for the ‘in service’ mobile fleet. Although the ‘in service’ target was essential to meet the client’s sound specifications, we expected our system would exceed this and therefore reach the ‘delivered’ target of 121dB LW.

To achieve these noise targets, Aletek offered a Multi-stage sound suppression exhaust system upgrade which included a primary and secondary silencer package, allowing the removal of the radiator attenuator (splitter) and engine bay panels. Our system was installed onsite within a 24-hour shift and can simply bolt-on to the existing chassis and existing support brackets with no welding required. The key benefits of this system are improved maintenance accessibility and visibility, a reduction in ambient engine bay temperatures and increased pay load capacity of approximately 1,500kg. Aletek are currently retrofitting the client’s entire 793D fleet with the Multi-stage exhaust system at a pace of one truck per day, and all trucks are now exceeding or maintaining the site specification of 123dB LW.