Case Study on Contamination Control
Like all industries, the mining industry is under increasing pressure to do more with less. Faced with falling profits, Smoky Canyon Phosphate Mine near Jackson Hole, Wyoming USA, set out to reduce maintenance costs. Like most open pit mines, the mobile equipment was identified as one of the biggest contributors to the mine’s ongoing cost.
The mine’s Reliability Team reviewed previous maintenance records and costs, and saw that the mine’s mobile equipment consumed 70% of the total maintenance budget. Haul trucks were responsible for the majority of these costs.
Based on this assessment, the Reliability Team knew that improvements to haul truck maintenance could result in substantial savings for the company.
The average engine rebuild cost was between $130,000 and $160,000, so any extension of engine life would provide significant cost savings.
In the late 1990s, the mine implemented a condition-based maintenance strategy of lubricant analysis. The goal was to extend the average rebuild interval for the haul truck engines.
By 2001, the average engine rebuild interval improved to around 18,000 hours, which was 5,000 hours more than pre-program average of 13,075 hours. OEM considered this new rebuild interval was 3000 hours beyond what was normal for the engine model.
The extension of rebuild interval was largely due to switching from a time-based (preventive) maintenance strategy to a condition-based (predictive) approach. (The full success story can be found in the May-June 2000 issue of Practicing Oil Analysis magazine.)
In 2001, buoyed by its success, Smokey Canyon mine formed a partnership with the Contamination Control Product Support Company. The team planned to study the effects of implementing a lubricant contamination control program on the final drives of its Caterpillar 785 haul truck fleet.
The mine’s initial goal was to extend the life of the haul trucks’ final drive groups and differentials. The Contamination Control Team’s goal was to assemble field data on the lubrication of mining equipment. These statistics helped the mine and other customers to realise optimum life from their mobile equipment.
The program called for the implementation of kidney loop filtration that deployed quick connects on the final drives. It also called for contamination control training for Lube Technicians and Inspectors, oil analysis and the integration of magnetic plug inspections and analysis.
The mine anticipated a transition from a time-based maintenance schedule to a condition based schedule.
The team worked on the mine’s Caterpillar 785 haul-trucks in the fleet. They set up a regular condition monitoring and inspection program, and through oil analysis, they controlled contamination levels in the oil systems. This extended the life of both the oil and the differentials.
At the same time, the team also improved overall fluid cleanliness levels on its Caterpillar 5230 shovels’ hydraulic systems and the hydraulic and transmission systems on its track-type dozers.
Because of this program, the maintenance staff became much more aware of the mine’s equipment, and much better equipped to make fact-based decisions.
The contamination control program and the switch to condition-based maintenance allowed the company to defer $280,000 in spending for the first quarter of 2003; proof that the contamination control program was working at Smoky Canyon Mine.