Hot maintenance tips for critical mine equipment (part 4)

Tip 4:  Bearings 

Bearings are found everywhere in a mine, especially in applications that help move the ore from place to another on conveyors. One example, crushers are critical to the processing side of many mines. These systems have conveyor bearings that are often exposed to long operating hours, extreme weather conditions and the external environment. These conditions can lead to contamination and metal-to-metal wear, which are common causes of conveyors downtime.

The trick with bearings is to choose the right lubricant and apply it correctly. Given the many operating parameters bearings are faced with (such as external environment, start/stop or continued use frequency, shock or heavy loads) lubricant selection can make a world of difference. Most of the time you need a grease, and other times you need an oil. It all depends on the application.

Grease is the most common method for lubricating a bearing. You should consider either lithium or calcium soap-based greases that have the right viscosity to balance gear protection and low temperature flow. Calcium based grease are preferred for wet applications given their ability to resist wash out. Greases can contain all the same additives that oils do, including extreme pressure additives and, in some cases, contain additives specifically to protect against adhesive wear. For application, typically less grease more often is preferred to purge and refill methods. This allows for continuous fresh grease to help push out contaminants, and ensure bearings are not overfilled.

Oils are also better suited for operating environments prone to external contamination, high heat and for some sealed bearings. Depending on the size and number of bearings, a centralized oil circulation system combined with advanced filtration systems, can help to keep the oil clean, and cool to ensure you achieving maximum bearing life.