Mohamed Mourad, industrial marketing advisor for Europe, Africa and the Middle East at ExxonMobil Fuels & Lubricants, explains the crucial role that lubricants play in increasing the efficiency of open gear equipment.

Making sure your mining equipment keeps producing for as long as possible is the key to a profitable operation.

That’s why many mining companies are dedicating significant resources toward equipment reliability and maintenance. In fact, equipment maintenance costs typically account for between 30% and 50% of a mine’s total costs, and as much as 60% of a mine’s workforce can be dedicated to servicing or repairing mining equipment.

Finding ways to improve equipment reliability and uptime will benefit your mining operation. Achieving this goal starts with best-in-class equipment maintenance process that optimises the performance of critical equipment in a mine, such as open gears.

Open gears are found in equipment such as shovels, draglines and mills, all of which play a central role in any operation. But, these components are often some of the most challenging pieces of equipment to protect, because they can be exposed to extreme temperatures, rain, snow, contaminants such as dust, and other corrosive materials.

Protecting open gears requires a multifaceted approach that considers lubricant formulation, application best practices and an understanding of lubrication-specific equipment.

So, here are a few tips to help optimise the performance of your open gear equipment:

Lubricant formulation matters

It is well understood that you need to use high quality lubricants to help ensure equipment reliability and extend equipment life. However, lubricant quality varies greatly, and to get the most out of your open gear equipment, you need to make sure you use lubricants specifically formulated for those applications.

Here are some of the common challenges for open gear equipment and how lubricant formulation can help improve performance in these conditions.

• Severe loads and extreme pressures – Open gears are subject to severe loads and extreme pressures, which can lead to significant equipment wear. Your open gear lubricants should be formulated using the heaviest base oil viscosity possible, as well as large amounts of extreme Pressure (EP) additives and solid lubricant additives, to help minimise wear and extend equipment life. Common solid additives include molybdenum disulfide and graphite.
• Moving components – Open gear lubricants must stay in place once they are dispensed onto moving components such as on shovels or draglines. This means they must be viscous and tacky, as well as possess excellent adhesive and cohesion properties.
• Extreme temperatures – Open gears are exposed to temperatures ranging from -45 degrees Celsius to +45 degrees Celsius, and while you will need a variety of lubricants with different viscosity grades, all your open gear lubricants must use a high quality base oil to perform in these extreme temperature environments.
• Open environments – Lubricants are often applied in open environments, exposed to the elements. As a result, they must be able to resist contaminants such as dust and dirt, as well as maintain lubricant strength when exposed to heavy rain or snow. Open gear lubricants must be formulated with the right base oils and additives to perform in these conditions.
• Root build up – Once lubricants have been applied to an open gear, spent product can sometimes build up in gear roots or cause ridges on sliding surfaces or gear teeth, resulting in root/tooth interference or excessive wear. You should use specially formulated lubricants, such as those with asphalt-free formulations, to avoid this issue.

Because using the right lubricants is such an important factor in the success of your mine, lubricant companies are formulating highly engineered lubricants with these conditions in mind.

For example, ExxonMobil offers an entire series of lubricants specifically formulated to meet the needs of open gear components – its family of Mobil Open Gear lubricants.

These lubricants are all formulated with high quality base oils and a specialised additive package – including Extreme Pressure additives and finely dispersed graphite to improve load carrying – to ensure that they can withstand the particularly intense operating conditions common to these operations.

They’re also formulated to form a cohesive and adhesive lubricating film that resists wear, water wash and excessive throw off.

Because lubricant formulation matters, it’s critical to pick high quality oils and greases – such as Mobil Open Gear lubricants – that can protect your equipment and ensure it continues to produce

Ensure proper lubricant application

Open gear lubricant formulation is important, but knowing how to apply the right lubricants is just as important in ensuring equipment performance.

Further, there is no one-size-fits-all approach to proper lubricant application, as each machine, component and lubrication system has its own specific requirements.

So, the first step to ensuring proper application is to periodically monitor lubricant films to make sure the lubricant is performing as needed. But, performing detailed component inspections during regularly scheduled equipment downtime is not enough. You should also monitor lubricant films on a regular basis so appropriate lubrication adjustments can be made on an as-needed basis.

If you monitor lubricant film strength on a regular basis, you should be able to notice telltale signs of over lubrication or under lubrication. When a lubricant is applied properly, it will typically appear dark, velvety and tenacious – the entire lubricated surface should have nice, even lubricant coverage and be resistant to wipe off.

Under application of the lubricant will leave components bare or shiny in appearance, and the lubricant may appear dry or flakey. Over application of the lubricant, on the other hand, may cause it to lose its adhesive and cohesive properties, leaving it to wash itself off the equipment.

It’s important to note that ensuring proper lubrication is a constant challenge, so having a dedicated team of on-site experts will go a long way in helping you optimise your lubrication program. The team – which should be kept small as possible to be effective and minimise mistakes – should be responsible for the ongoing monitoring mentioned above.

If this team decides that any adjustments need to be made to the lubrication program, the adjustments should be well documented to avoid any duplication. Further, it’s critical to only make small adjustments and then give those adjustments time to take effect before making a decision on their effectiveness.

You can always partner with your lubricant supplier for further insight into application best practices. For example, ExxonMobil’s Field Engineering Services team offers expert advice on lubrication practices – including application – as well as proper lubricant selection, equipment trouble-shooting and other lubrication services that can help equipment run longer.

Understand Your Centralised grease system

Finally, it’s also critical that you understand the equipment used to deliver lubricants to the open gear components.

Today, most mines use centralised grease systems to deliver lubricants. These automated systems can utilize a variety of delivery methods – including direct injection, drip tubes or lubricant sprayers – and they also allow for the delivery of numerous lubricant types to best suit a component’s specific conditions, including different viscosity and NLGI grades.

As a result, this equipment can help reduce downtime by improving maintenance efficiency, help manage proper lubricant application, and help improve safety by reducing human-machine interactions.

Your maintenance team should understand this equipment’s function and design in order to manage the system effectively and troubleshoot any issues, if necessary. 

Don’t underestimate open gear lubrication

Open gears are critical components in some of the most common and important equipment found in mines today, and understanding how to properly lubricate these components will have a valuable impact on your business.

To get the most out of your programme, it’s also important to work with a lubricant supplier that has the application expertise and on-the-ground knowledge you need to make smart equipment maintenance decisions, particularly when it comes to your open gears.

This is because these partners can offer valuable equipment insights. Take, for example, ExxonMobil, which has been working with leading equipment builders for more than 100 years to develop tailored lubrication formulations that protect their equipment even in difficult conditions.

This insight, combined with the company’s leading lubrication technologies and wide range of expert technical services, can help you better understand maintenance best practices for your equipment and optimize your maintenance approach.

In sum, following these steps will help ensure you maximize the performance of some of the most critical equipment in your mine, which, in turn, will help you achieve significant benefits to your productivity and bottom line.