February 2, 2010
With proper care and handling, some mobile equipment can enjoy a second life before being replaced.
by Daniel C. Brown, Contributing Editor
In today’s economy, everyone is trying to stretch dollars as far possible, and the aggregates industry is no exception to this trend. With nearly 40 percent of respondents to Aggregates Manager 2009-2010 Forecast study who reported they intend to decrease capital spending this year, many operators throughout the nation are looking for ways to extend equipment life at their sites.
What does this mean for day-to-day operations? Many operators run equipment for more hours than normal. Capital for new machines is scarce so equipment is being kept longer and worked harder. Knowing that the equipment has to last, managers carefully watch oil samples for wear particle signals that mean component failure is approaching. And some equipment managers are even replacing small components, such as water pumps and alternators, before they fail.
Finding the “sweet spot”
Although at first glance, longer equipment life may cause concerns, the actual age of the equipment isn’t the key parameter, says Dan Connelly, vice president of equipment services, Oldcastle Materials Inc. in Atlanta. With about 40,000 pieces of rolling stock and eight divisions, Oldcastle is one of the nation’s largest integrated construction materials companies.
Connelly says that because its demand is down, Oldcastle’s equipment is being kept longer. But, he adds, the equipment is not working its usual number of hours. “Operating hours, not calendar days, is the important factor in determining our replacement cycles,” Connelly says.
He says Oldcastle strives to replace most equipment at the “sweet spot” — the optimum point in a machine’s financial life just before its repair costs balloon and major components need to be replaced. Oldcastle determines its own sweet spot for each category of equipment, based on historical records and analysis of owning and operating costs.
However, in some categories of equipment, such as 7-cubic-yard wheel loaders, Oldcastle considers going for a second life by replacing major components. Forty-ton and larger rigid frame haul trucks would also be considered for major component replacements. The company owns about 500 dozers and 800 excavators, but “typically we don’t rebuild them,” Connelly says.
How about replacing small components before failure? Yes, says Connelly. “We certainly attempt to replace components such as starters, alternators, and water pumps before failure,” he says. “We advocate condition-based maintenance.”
The level of service that Oldcastle procures from equipment dealers depends on the relationship of each division with its local equipment dealers, Connelly says. Each division has multiple shops that do preventive maintenance and some repairs.
Oldcastle also uses Viewpoint management software, which has an equipment module that identifies each piece of equipment by a unique number. Revenues, as well as operating hours and all costs, including oil changes, parts, and repairs, are tracked for each piece of equipment. “We take data that is housed in Viewpoint to determine the optimum equipment life cycles,” Connelly says. “We look at each piece of equipment multiple times each year.”
Keeping it longer
The Washington Division of URS Corp. keeps equipment based on site-specific applications, says Bob Merritt, director of maintenance at the Boise, Idaho-based firm. The Washington Division owns 2,000 plus pieces of equipment that work at construction sites, quarries, and mines around the world.
“We keep equipment on long-term projects based on application and production,” Merritt says, noting that while many operators try to get rid of machines before the first major rebuild, his company may hold it longer and go through one or two rebuilds on many pieces. “The number of hours is driven by the class of equipment,” he adds.
Take 50- to 70-ton excavators, for example. Washington has some that range from 14,000 hours up to around 25,000 hours on longer-term projects. Front shovels and mining excavators run longer — up to 60,000 hours.
How about dozers? “Typically we try to get rid of the less-than-300-horsepower class at about 10,000 to 12,000 hours; the 300- to 500-horsepower class in 20,000 hours, and the above-500-horsepower class in 50,000 hours,” Merritt says. “Even at those hours, that’s longer than most people run them.”
Washington Division will do a major rebuild at 12,000 to 14,000 hours on a construction dozer. That means the complete power train gets rebuilt components —engine, transmission, torque converter, and final drives.
Why keep equipment longer? “If it adds value, we do it,” Merritt says. “In the last few years, until the downturn, it’s been difficult to get the equipment we needed. The low availability of new and used equipment made the price go up. Now, with the change of the economy, lots of equipment in the smaller- to medium-sized classes is currently available.”
Planning for the long term
While lower-than-normal demand and slim profit margins have swayed some operators to keep equipment longer than planned, they run the risk of catastrophic failure if the machine is pushed beyond its limits. The two main concerns are having an equipment failure cause the entire plant to shut down and losing any residual value of iron assets that are not saleable. If a company decides to hold onto equipment, planned, predictive maintenance and component change-outs are recommended.
“Through scheduled maintenance, we’ve gotten as many as four life cycles, or 24,000-plus hours, out of large wheel loaders,” says Mike Monnot, vice president of equipment for Worcester, Pa.-based American Infrastructure. The wheel loaders work for a subsidiary called Independent Construction Materials. He recommends getting expected component lives from the manufacturers, then watching all indicators of wear — oil samples, vibration analysis, wear measurements, and the like. “You come as close to that end of life as you can,” he says.
Through careful planning and proper maintenance, operators who plan to delay capital expenditures can extend the number of hours they get from their mobile equipment. But best practices for equipment maintenance make sense for all operators, not just those looking for longer equipment life.
To keep mobile equipment running smoothly, consider the following guidelines.
– Perform daily maintenance according to manufacturer recommendations;
– Clean windows and mirrors;
– Check front and rear lights;
– Inspect the seat belt;
– Review electronic fluid monitoring and air filter reports;
– Use clean fuel with low sulfur content; and
– Avoid over-servicing the machine.
– Check coolant level;
– Check engine and hydraulic oil levels;
– Drain water from fuel separator/tank;
– Test indicators and gauges;
– Inspect the undercarriage and track adjustment;
– Inspect the boom, stick, and bucket and lubricate linkages;
– Inspect the seat belt; and
– Test the travel alarm.
– Perform regular sampling and oil analysis;
– Check coolant level;
– Inspect linkages;
– Inspect the bucket and its cutting edge; and
– Look for leaks from hoses and cylinders.
– Select the right tire for the application;
– Follow the manufacturer’s air pressure recommendations;
– Check tire pressures at the start of a work shift;
– Train operators on proper procedures;
– Remove hazards from haul roads and workways; and
– Follow the recommended maintenance schedule.