On the top tier

The cleanest high horsepower diesel engines operating in mining in Australia today are the Cummins Inc. QSK50 and QSK60 Tier 4 Final units powering haul trucks and excavators in the NSW Hunter Valley.

In fact, these are the only high horsepower mine engines in service in Australia today with Tier 4 Final compliance, the most stringent off-highway emissions standard in the world.

 
Of course, the challenge is producing cleaner-running engines while not compromising life cycle costs, and Cummins is working with mining companies to deliver a technology road map that not only reduces fuel consumption but also results in increased engine life and longer service intervals.

These benefits are vital as mining companies commit to a decarbonised future.

Tier 4 Final has required the most significant change ever in high-horsepower engine technology. Cummins achieves the standard using a combination of clean in-cylinder combustion and integrated Selective Catalytic Reduction (SCR) exhaust aftertreatment.

SCR was selected for a number of reasons, including lower heat rejection (compared with exhaust gas recirculation or EGR), minimal base engine changes and simplified maintenance.

Cummins’ entire high-horsepower engine family, which includes the QSK19, QSK23, QST30, QSK38, QSK50, QSK60, QSK78 and QSK95 and spans 800 horsepower to 4400 horsepower, is now offered with Tier 4 Final compliance using SCR technology.

Diesel particulate emissions are slashed with the Cummins Tier 4 Final engine, by 80% compared with the Tier 2 product, meaning less soot loading in the oil.

“The cleaner-running Tier 4 engine means longer oil drain intervals because of this reduced soot loading in the oil,” said Stewart McKeddie, OEM business manager for Cummins South Pacific. “In fact, oil drain intervals are doubled, so a 250-hour interval becomes 500 hours with a Tier 4 engine, and the engine’s oil filtration matches this extension.”

Cummins’ Eliminator oil filtration system – replacing the traditional spin-on filter elements – and increased engine oil capacity through a larger oil pan are other features enabling even longer oil drain intervals.

A 3 % -5 % improvement in fuel consumption with the Tier 4 Final engine over the Tier 2 unit provides another significant maintenance benefit, as well as a huge reduction in greenhouse gas emissions.

 
“The fact the engine is burning less fuel means engine life is extended, by up to 12 months in some mine operations in Australia,” McKeddie said. “At the same time, mid-life component change-out is significantly reduced, with most components returned to the engine on an ‘inspect and re-use’ basis. In fact, belts and belt tensioners are the main components that need to be replaced mid-life.”

Cummins’ remote engine monitoring system, PrevenTech, is another critical element in the maintenance equation. 

A real-time digital monitoring and reporting system, PrevenTech provides complete 24/7 engine health management, helping reduce downtime by prioritising and notifying when actions are required. Alerts and recommendations are sent through by the Cummins Care team via email, phone and a web-based customer dashboard. The system increases technician safety and efficiency by viewing live engine data remotely without the need for technician/engine interaction.

Whitehaven Coal reports it is achieving significant benefits through the implementation of PrevenTech in that it is now being more proactive, and less reactive, with maintenance practices and that means reduced operational and maintenance costs.

The system is being used at Whitehaven’s newest and largest open cut mine, at Maules Creek in the NSW Gunnedah Basin, which has production approval for 13 Mt run-of-mine coal per annum. The Whitehaven fleets at Tarrawonga and Werris Creek mines, which have 3 Mt per annum and 2.5 Mt per annum production approvals respectively, are also being connected to PrevenTech.

All up, around 100 Cummins engines in haul trucks and excavators will have PrevenTech connection at the three Whitehaven mines.

PrevenTech works by applying connectivity, algorithms and analytics to a machine's engine hardware, helping a mine identify and diagnose issues faster and more accurately. It works with Internet of Things (IoT) technology and global security standards.

Whitehaven reports that during a trial period with PrevenTech it had only had 10 engines connected but still prevented a couple of potentially major downtime events. The machines were diagnosed and then repaired in a short period so as not to interrupt production.