Over-lubrication is an issue that challenges mine operators and can cause significant damage to mining shovels. This problem can often be attributed to poor communication between mine operators working different shifts, lack of training on shovel lubrication systems and inspection and reporting, as well as misinterpreting how the lubricant should be applied or not selecting the right lubricant for the environmental working conditions. While using more lubricant may seem like a safe option, it could cause mechanical issues because when shovel gears or sticks are over-lubricated, the fluid can sag and drip off, leaving the metals exposed to contact. The result is unexpected maintenance costs and increased downtime while repairs are undertaken.  

The impact of over-lubrication can be severe but also easily avoidable by focusing on proper application, enacting correct maintenance practices and minimizing workforce errors. Below are some techniques to consider when lubricating points on mining shovels.

Typically, shovel open gears operate in strenuous environments like open pits and quarries which expose the equipment to extreme temperatures, as well as abrasive dust and dirt, as well as water that can result in corrosion. These add to the difficulty in achieving optimal lubrication. While many of these factors are out of a maintenance manager’s control, the quantity of lubricant applied to an open gear is manageable and can mitigate wear caused by exposure.

To gauge optimum lubricant quantity, mine operators must understand the product they are working with and keep the centralized lubrication system properly functioning. Petro-Canada Lubricants VULTREX™ line of grease-based Open Gear Lubricants (OGL) needs less to be applied to the equipment, compared to other products, which helps prevent over-lubrication. 

Additionally, operators should be trained to look for key indicators of a properly applied lubricant. For example, when properly applied, the tooth face of the gear will show a small film of lubricant which appears black or dark grey and feels velvety. Conversely, when over-applied, it can seem like it has washed itself off, making it difficult to see the film left on the surface. 

These recommendations are valid year-round, but there are also seasonal considerations to keep in mind. In colder climates, additional lubricant needs to be applied to keep the protective film workable on metal surfaces, while warmer conditions require less product to reduce the level of ‘fling-off’ and messy, lubricant consumption.

Shovel sticks have similar lubricant demands to open gears. In cases of over-lubrication, the plating effect is reduced on the metal running surfaces. This results in the stick surface being more susceptible to extreme weather conditions. When properly lubricated, the stick should have minimal lubricant build-up towards the bucket and on non-running surfaces, which enables better resistance to adverse weather conditions

While over-lubrication is a common issue, it is easily avoidable. The key is to keep all maintenance personnel and operators trained in proper lubrication techniques, that the lubrication system is operating efficiently and that the application doesn’t become a secondary consideration to choosing the right lubricant. Selecting the correct lubricant can result in extended equipment uptime, reduced maintenance costs and security of operational goals.