Maintenance lessons from the mining industry

Mining machines are the giants among giants – trucks with 13-foot-tall tires, dozers with 850-horsepower engines and shovels that gobble up 50 cubic yards with a single bite.
This equipment is so big and expensive it has to be managed with a precision and rigor that rivals the engineering efforts at NASA. Many of the machines work two shifts a day, some even 24 hours a day with 98 percent availability. Shutdowns are rare, and often planned weeks or months in advance.

While most of you rarely use equipment of this magnitude, there’s a lot anyone can learn from the practices developed to keep mining equipment moving and profitable. Some of this is so advanced it may not relate directly to how you manage smaller equipment such as backhoes and trenchers. But some of the technology is already trickling down to smaller types of equipment – especially electronic engine technology. And if you know how the game is played in the big leagues, it can help you with your game regardless of the league you’re in today.

Rebuildable engines
Most construction equipment owners think long and hard about keeping a piece of equipment once it comes due for an engine rebuild. In mining trucks it’s expected you will rebuild the engine at least three times, says Jim Evans, chief engineer on Cummins high horsepower platforms.

Depending on the duty cycle, it’s not uncommon to run a big mining truck engine for 20,000 to 30,000 hours between rebuilds, Evans says. The block itself and other non-wear items are designed to essentially last indefinitely, provided the engine is well cared for and maintained.

But riding out a problem until a part fails is not an option. “We’ve moved from what we call breakdown maintenance to predictive maintenance,” says Rick Ochs, Liebherr’s director of operations for the Western United States. “We try to predict the life of each component and remove it before it fails. If you run a component to failure, it can take out other components or damage components to the point where they can’t be rebuilt.”

Being proactive instead of reactive is a proven money saver, Ochs says. But with 56 mining trucks running 24/7 under his watch, predictive maintenance requires a lot of hustle. Inspections and minor maintenance are done like pit stops, scheduled during the operators’ lunch breaks or during shift changes. What can’t be addressed in that brief period of time is rescheduled for the next oil change or scheduled maintenance. His technicians have just 12 hours to complete these scheduled PMs and that includes sampling not only engine oil, but every fluid on the piece of equipment.

Computer software tracks all the maintenance to help technicians fine tune their care of the equipment and the timing of repairs. “You have to spend time watching and tracking each component, but it really does save money,” Ochs says.

The 4,000-hour oil change
New technology is playing a major role in keeping these high-horsepower engines healthy. For example: 4,000-hour oil changes.

Oil has to be changed on any machine, but pulling a multi-million-dollar truck out of service is expensive from a productivity standpoint. Cummins developed a product called Centinel, Evans says, which burns the old oil while replenishing the sump with new oil out of an onboard reservoir. The oil replacement can be automatic, or, using electronics, set up based on the amount of fuel burned.

Traditional filters can be used with the system, but Evans recommends a centrifuge-type filter to eliminate the chore of frequent filter replacements as well. “That way you can schedule the engine service to match the other vehicle service stops,” he says.

Live feedback from the engine
Another technology tool used on big mining engines is electronic monitoring. “We monitor the exhaust port temperature on each cylinder; we look at the fuel burn rate, the boost pressure, the coolant temperature, coolant pressure, all those parameters that access the engine health,” Evans says. “We also measure the blow-by so we can tell when the engine begins to wear.”

This information can be downloaded on a laptop by a service technician and checked on a periodic basis or sent via radio transmission from the vehicle to the dispatcher for real-time diagnostics. Information can also be relayed over the Internet, or via cell phone technology to a pager worn by a technician. “I can sit here at my computer and watch how an engine is performing in another part of the world,” Evans says.

Electronic monitoring also makes it easier to do diagnostics and compare trends in data. And charting trends helps you see problems on the horizon and adjust maintenance or operator practices and schedule maintenance.

Remote diagnostics is also helping alleviate the shortage of technicians and the difficulty of getting a specialist to a remote site. “Sufficiently trained people are getting harder to find,” says Ochs, whose trucks operate in the remote Wyoming coal country. “Having an engineer troubleshoot from Atlanta or Newport News, Virginia, is pretty valuable.”

On smaller types of equipment onboard computer diagnostics are not as elaborate, but they do exist and are becoming more useful for maintenance managers willing to chart trends, spend time analyzing the data and use the information to schedule and predict future maintenance needs.

Tracking fuel as a lifecycle indicator
Engine hours are the traditional benchmark for determining the lifecycle of engines and transmissions. But most equipment managers in the mining industry have switched to counting the number of gallons of fuel burned as a lifecycle indicator, typically a million gallons between rebuilds for the big 50- and 60-liter engines that Cummins makes, Evans says.

Cummins believes that life to overhaul is best measured by gallons of fuel burned because of the variability in load factors, Evans says. With oil analysis to guide maintenance intervals and a load factor in the 30 percent range, Evans says he would expect to see 30,000 or more hours from a Cummins high-horsepower engine. Burn the fuel faster, rebuild the engine sooner. Burn the fuel over a lower load factor and the engine will last longer to overhaul.

The same principle applies to smaller equipment. The challenge for managers of smaller equipment, though, is keeping track of the amount of fuel burned. A typical scraper or dump truck may work at multiple sites and get refueled by different sources – making recordkeeping difficult. Most mining machines have onboard electronics that measure exactly how much fuel they burn. Still, the accuracy of fuel-based lifecycle calculations is unquestionable, and the practice has a small group of loyalists among the construction equipment managers. If you’re willing to put in the effort of recording a machine’s fuel consumption, it will prevent you from rebuilding an engine too soon, or even worse, too late.

Evans acknowledges the decision to rebuild an engine has to make economic sense, regardless of the size of the equipment it powers. With mining equipment, rebuilds are assumed. With smaller equipment, dropping in a factory-rebuilt engine or trading out the whole machine for a new model may be a better option. The lesson to take away from the mining industry is you should know precisely what the economic breakeven point is for rebuilds and do your best to manage component life up to that point.

Productivity is everything in mining. When they are running multi-million dollar machines, mining companies push for uptime/availability rates as high as 98 percent.

Close collaboration on fuel and lubes
Fuel and lubes are a cost of business regardless of the size of the equipment you run, but when you’re burning through 100,000 gallons of diesel in a day, as do some mining companies, you’ve got to do more than grab the low bidder and cut them a check every month.

Jim Gigante, director of ConocoPhillips’ energy segment businesses and mining and off-road construction, says most mining companies are looking for a relationship with their fuel and lube suppliers, one that includes such value-added services as oil sampling and collaboration with the mine’s maintenance team and other OEM suppliers. “Once they understand the value these partnerships bring and see that this can put hard dollars back into their operation, then price is not so much of an issue,” he says.

Companies that are serious about component life extension have upgraded their oil analysis strategies in recent years, Gigante says, and the Internet has had a big impact. “The data comes to you at light speed,” he says, “but it’s what you do with the data that’s important.”

If the oil analysis provider gives you the ability to chart and trend the data on a computer, and the lube provider, the customer and the OEM can all share the data, then your preventive maintenance program can take a giant leap forward. You can analyze how well your lubes and filters are performing, optimize drain intervals, study and if necessary change maintenance practices and plan downtime months in advance.

And if oil analysis enables you to predict future maintenance needs, then the conflict between maintenance and productivity is reduced, Gigante says. You can extend oil change intervals or coordinate them with other service schedules. Inventory levels are reduced. Critical spares are held to a minimum while labor and redundancies are reduced. There is more room in the shop – all things that help the bottom line.

Fuel, lube and repair shop cleanliness have also become important factors in the mining industry. In high-horsepower engines with high-pressure fuel injection even the smallest amount of contamination in fuel or lube oil can accelerate component wear. “In the past five years we have seen the major mining companies emphasize the cleanliness of their lubricants by having a program to clean up their bulk tanks, and their transfer points,” Gigante says.

Big ticket tires
After fuel, tires are the biggest recurring expense associated with mining equipment. Some of the bigger tires can cost as much as a new pickup truck. So mining companies take a very methodical approach to pricing and managing these consumable assets.

“Today’s mining companies determine which suppliers are critical to the operation and which are not,” says Kaan Demirel, Michelin’s market segment manager for North America. “Once you define that relationship you want to move from a transactional day-to-day business model to a long-term association where the supplier brings their expertise and works with the customer to improve the productivity of the operation.”

Tire management is also being boosted by software programs that track usage trends and give you comprehensive data about the tires in your fleet. “It’s very important to know what your total cost of ownership is,” Demirel says, “not just the purchase costs.” With tire management programs you can factor in repair costs and downtime and track and compare tire performance over time and get a much more accurate picture of which products perform best and what your true costs are.

Safety and training are key components in the relationship between tire suppliers and their mining customers, and Michelin runs a training center in South Carolina. And since not all customers have the resources to attend off-site training sessions, Michelin recently launched a tire maintenance and safety training program that its field sales representatives take to mines and quarries throughout the country in a train-the-trainer type approach.

Most maintenance people are mechanics, not tire engineers. By asking their tire vendor to provide training as part of a package of services, maintenance managers can realize immediate increases in machine uptime and, over time, decreases in the cost of putting rubber on the road. “We’re not trying to make everybody tire experts,” Demirel says. “What we try to do is explain what tires are all about and why tires behave a certain way under certain conditions. How do you prevent tire failures? What are the critical criteria?”

Customer-dealer relationships
Perhaps the most striking difference between the maintenance program for mining equipment and that of smaller construction fleets is the close working relationships between OEMs, dealers and mining customers.

“In mining you cannot afford not having a relationship with your customer,” says Alfredo Banos, mining account manager for Cummins. “In this day and age, service is the key in any industry. If the distributor is providing world-class support, the customer will usually take that into account in making his decisions.”

One aspect of that relationship for many mines, Banos says, is for the distributor to provide trained technicians with sophisticated electronic tools to better support their customers. In the Cummins process the distributor works closely with the OEM or mine maintenance personnel to minimize equipment downtime for the mine operator. This is done by coupling preventive maintenance schedules whenever possible. The foundation of this teamwork is the relationship between the mine, the OEM and Cummins, Evans says. The Cummins-trained technician not only provides a level of expertise the customer could never achieve on his own, but can also have his labor built into the cost of the overall package from the distributor. This provides the mine much more flexibility about how it trains and uses its own maintenance personnel.

Priced by the hour
Another benefit of close collaboration is that many mines and OEMs have enough data and experience that they can write their contracts for equipment on a cost-per-hour basis. Few construction customers would warrant a full-time technician from the dealer or OEM. But service agreements and cost-per-hour contracts are becoming increasingly popular in competitive bid environments where contractors need to know to the dime how much each element of a job is going to cost them. What the small fleet manager has to do is first ask for this level of service as a part of a larger relationship, and second be willing to rethink how they allocate equipment costs.

“At the end of the day, the mining customer is more interested in hauling material,” Banos says. “They don’t want to be maintenance people. That’s why they like cost-per-hour contracts, because the maintenance is in the hands of the experts.”