Historically, PM has meant Preventive Maintenance and maintenance programs have been called Preventive Maintenance Programs. PM programs generally include greasing, changing filters, changing oil, flushing cooling systems, steam cleaning equipment and replacing minor components. PM tasks are typically performed at regular intervals, 250, 500, 750 and 1,000 hours, while some are scheduled based on recommendations by the original equipment manufacturer. In addition to regularly scheduled maintenance, some PM programs include replacing components at intervals recommended by the original equipment manufacturer.

What we are really trying to accomplish with our PM programs is to prevent components from failing prematurely. If the average life of an engine is 12,000 hours, we want to implement maintenance procedures to keep the engine from failing at 6,000 hours. To prevent the engine from ever failing may cost us more in labor and materials than the cost of a new engine. We could spend $50,000 in a six-month period trying to keep an old engine running while the cost of a new engine is $35,000.

In addition to preventing premature failures, predicting when a component is going to fail also is beneficial. Being able to predict when a component would fail could add more to a company's bottom line than any other maintenance procedure we could ever implement. In addition to preventing premature failure, maintenance programs should include procedures and programs designed to predict component failure.

There are several very common procedures for predicting component failure. These procedures include collecting and testing oil samples from drive trains and gearboxes for metal contamination. It also pays to inspect screen decks for wear and small holes and truck frames and front-end loader lift arms for cracks and other signs of metal fatigue. Motor, reducer and gearbox vibration analysis is another tool to predict failure. Vibration analysis indicates the condition of the bearings, motor alignment and other key factors — it can be a very powerful tool to predict the life of a component.

A predictive maintenance program is supported by an Equipment Management System that can track component life, cost of scheduled maintenance, cost of labor and materials for repairs, and lost production related to scheduled maintenance and breakdowns. Tracking lost production is a difficult task for maintenance personnel to perform because it points the finger right at us when we do an inadequate job. However, tracking lost production is the best and most objective method of measuring improvement and success.

In addition to the reports generated by an EMS, you could develop Key Performance Indicators to monitor the effectiveness of a predictive maintenance program. Measuring the minutes the loader or plant actually operates compared with the minutes it is scheduled to operate, using a maintenance efficiency factor and monitoring operating cost per ton, are a few KPIs that could be used.

We may not always have enough money to completely eliminate component failure, but controlling and managing component failure through preventive and predictive maintenance could add minutes to your equipment's operating time and additional profit to your company's bottom line.

Every maintenance person dreams about equipment that never breaks down and components that get replaced before they fail. Using a predictive maintenance program to predict failure can help make that dream come true.

Bill Huber, vice president with Weir International Mining Consultants, has more than 30 years' experience in mining operations and engineering.