Carefully consider truck flow through the site. “Some applications have a constant flow of trucks. Then there are other applications where you can’t always control the amount of time in between trucks,” says Ellis. “If you have consistency in trucks, it is not that difficult to figure out what you need. But you do need to look at long term. In the long term, what is the site going to look like? Are we talking about a permanent spot or something that is moving?”
Be cautious about the true limitations of bucket size relative to material density and wheel loader capacity. Some customers try to gain an advantage by using a larger bucket. Bell has witnessed this firsthand over 45 years in the industry. “If they had a 3-yd. loader, they wanted to make it a 3 1/2-yd. loader somehow,” he comments. “If they had a 4 yd., they wanted to make it a 4 1/2 yd. People are always trying to push these machines beyond their capability.”
Overloading a machine accelerates wear. “If you sell a smaller machine to do the same work, you can sell a customer a lower cost per ton, at least in the purchase price and probably most of the operating cost,” says Bell. “But if you ask a machine to take 20% more, it will probably last 20% less overall. It does not make sense that you can do 20% more work and not wear the machine out more quickly.”
Of course, operating costs are going to escalate as the machines grow larger. “A larger machine burns more fuel,” says Ellis. “Look at the fuel burn vs. the actual productivity that you are getting out of it. Just the cost of maintenance — tires cost more on a bigger machine. The whole overall hourly cost is more the larger the machine that you get.”
When versatility and speed trump size
Poland Sand and Gravel, Poland, NY, has a large product base, offering 20+ products. Its wheel loaders have to perform multiple functions around the jobsite with operators shuttling machines to where they are needed.
“There is a lot of movement in our operation. We need good travel speed and good acceleration,” notes Scott Rommel. “Our piles are spread out.”
The wheel loaders have to perform a variety of tasks including load-out, carry and stockpile. “Being quick around the pit is important,” says Rommel. “In order to be quick around the pit, you need a decent ride and a feel of stability. In addition, we are running up and down slopes because we are essentially a hillside operation.”
The company’s wheel loader fleet currently consists of a Doosan DL500, DL450, DL400 and Komatsu 380, along with a few smaller loaders for cleanup. “We started out with 3- and 4-yd. loaders,” says Rommel. “Now, we are up to a 5-yd. machine with the 400, the 500 is 6 3/4 yds. and the 450 is right in between. It is probably a 6 1/4-yd. machine the way we have it set up with our cutting edge on it.
“We started with small loaders and kept going bigger,” he continues. “At some point, you say ‘do they make one big enough?’ But when you get into the large loaders that are hugging $800,000 or more, then they are pretty much dedicated to production. They are too big for the load-out in our operation.”
Versatility of the equipment is a key consideration. “We try to maintain some versatility with our machines because we are a smaller operation,” says Rommel. “We are probably loading in the area of 9,000 tons in an average week. If you were doing straight production load-out, biting the bullet and buying one of the bigger, more expensive machines in the beginning would be the way to go if you could afford it. It is just going to save you money in the long run.”
Due to truck weight regulations in the state of New York, a larger loader wouldn’t really have much impact on load-out times. “Generally, we are around the 22- to 23-ton payload on the tri-axles in New York with the permitted loads,” says Rommel. “Our yields are about 1 1/2 tons/yd. for our base mixes. So when you are running 23 tons, that is about 15 yds. You would have to have a pretty big machine to do that in two passes.
“Then they are getting slower,” he adds. “They can do it, but they don’t move around the pit like these smaller wheel loaders do.”
That said, larger wheel loaders can offer an attractive return compared to smaller units. “If you look at it from a production basis — tons moved over the life of the machine — the costs associated with the bigger wheel loaders are going down,” says Rommel.