Using PdM Technology to Reduce Downtime in Mines

Predictive maintenance (PdM) has the ability to increase productivity and reduce downtime in many industries but particularly at mine sites, where it can be used to support operators by rescuing their budgets and allowing them to focus on their core functions.

Mining operations and machines are vastly varying and complex, including drills, trucks and processing equipment. Each part has its own difficulties and wear points, any of which could fail if unmaintained and cause significant periods of downtime.

"Predictive maintenance is now an 'expected' feature of a fleet management system," noted Martin Politick, director of research and development at Wenco International. "Miners have it on their checklist of features they must have."

Advances in technology have made PdM a possibility, as the availability of cheap computing power enables organizations to gather, store and analyze data. By some counts, more than 40 technologies are being used for predictive maintenance. These technologies include infrared thermography, sonic/ultrasonic analysis, motor current analysis, vibration analysis, oil analysis, sensory analysis and wear particle analysis.

Infrared Thermography

A non-contact infrared imager can be used to quickly obtain a multi-point temperature profile that can easily be assessed.

Sonic/Ultrasonic Analysis

These instruments generally sense sounds in the 20- to 100-kilohertz range and convert them to either auditory or visual signals that can be heard/seen by a technician. These high frequencies are generated by worn and underlubricated bearings, faulty electrical equipment, leaky valves, etc.

Motor Current Analysis

In the realm of electric motors, the current signature can be measured and recorded. Motor current analysis can be used to identify issues with belts and couplings through trending and baselining.

Vibration Analysis

By measuring displacement, velocity or acceleration, you can gain insight into bearing failures, imbalance, misalignment, wear, looseness, etc.

Oil Analysis

Oil analysis can be broken down into three main categories: lubricant health, machine health and contamination.

Sensory Analysis

Most operators and technicians are familiar with the machinery they maintain or operate and consequently are aware of the normal sounds of that machine, making them qualified to identify unusual conditions.

Wear Particle Analysis

Wear particle analysis provides direct information about wear conditions inside the machinery. This information is derived from the study of particle shapes, composition, sizes and quantities.

The advantage of having all these PdM technologies is that problems can be diagnosed from different sources, allowing the diagnosis to be more accurate and maintenance personnel to respond at a faster rate and with more confidence.

The latest PdM technology works by monitoring the systems of critical equipment and uploading the data to consoles where maintenance teams can review the performance and health of the equipment. They can then make a decision based on this data to intercept potential failures or problems before they occur. Unfortunately, Politick believes operators are not yet using these technologies to their maximum potential.

"Most of our customers are still using the tools in a reactive mode," he noted. "But it allows them to be a lot faster at reacting. Right now, it's about how we can get the ore out as fast as possible, not as low cost as possible."

Through PdM technology, General Electric (GE) recently picked up subtle changes in the bearing and oil temperature of a large electric motor and gearbox that did not fit the usual pattern.

"It turned out that the cause was a loose terminator contact point, and the correction avoided gearbox damage and unscheduled downtime," said Derick Moolman, commercial product leader for GE Intelligent Platforms. "We see an increasing number of cases where the analytics avoid gearbox failures — a common pain point in the mining industry."

According to Politick, the impact of PdM technology could be huge.

"The maintenance department can easily take 40 percent of the budget of the mine's operation, so the potential is significant," he added.

Although mining machinery is some of the most durable equipment on the market, the underground environment is harsh and machines will deteriorate without an ongoing maintenance plan. This necessitates continuous training of maintenance crews on the newest technology and techniques while adhering to strict standards to ensure all machinery is safe and reliable.

As the industry trends toward more automation, the ability to diagnose and operate equipment efficiently and safely will become more important. Mining companies that invest in PdM technologies and training of their personnel will give themselves a distinct advantage in the field.