Land clearing operations are a bit like a boxing match. The idea is to knock them down and grind them up…and to do it in as few rounds as possible. While there is more to land clearing than that, the strategy is the same. An efficient operation will clear a site quickly, process the material and then, typically, haul it off-site for further processing and recycling.
Both chippers and grinders play a role, although—like flyweight boxers and heavyweight champs—each deals with materials in its own class. And different strategies are called for in different cases.
"The first thing you need to think about is where you are going with your product," says Mark Lyman, president of West Salem Machinery, Salem, Ore. "Marketing is strictly local. Before you take any steps you need to understand the local markets and maximize your production of the highest-value product."
"Be sure you bring in the proper type and size equipment for each job," says John Foote, vice president of sales and marketing for Morbark, Winn, Mich. The first step is to have a grasp of the job as far as volume and material being handled. A small lot is in different class than a multi-acre site, Foote points out.
"The smarter guys look at their nearby markets," he adds. He notes that will allow a recycler to maximize production of the highest value end-product. A sharp eye will pick out saw logs and sell them to mills while chipping the rest.
"The deciding factor is the end use of the material," agrees Travis Lint, large equipment sales manager for Bandit Industries Inc., Remus, Mich. For instance, if a recycler is producing boiler fuel, he most likely will opt for a chipper.
"Use a chipper especially if you have to haul the material a good distance," Lint advises. This is because the chipper will allow the recycler to put more material in each load and maximize diesel fuel efficiency by moving more material per ton mile.
Depending on the mix of materials, reducing the volume on-site can cut the haulage anywhere from 3:1 to 6:1 or more. With hauling costs today, most recyclers need to move materials to local markets or not at all.
GETTING IT DONE
Another important factor in getting the job done is speed. "We run a fast-paced operation," says Dave Fitzgerald, president of Fitzgerald Excavating, Covington, Va. Whether it is a one-acre lot or a 100-acre job, he sends out basically the same kinds of equipment. Of course, the larger job will have more units working.
Fitzgerald says on one of his typical job sites, there will be the three Morbark 4600XL’s, feller-branchers, two shears, hoes to dig stumps and skidders to pull the trees. Fitzgerald has his own small fleet of log trucks to haul larger saw logs out.
With that equipment, it will take a week or week-and-a-half to do a 100-acre job, including shearing the stumps. "We can do four or five acres per day with two hoes," Fitzgerald says. They will slice and dice stumps and logs before feeding them into the grinder.
Fitzgerald’s primary market is for mulch. "We grind it to six inches and then haul it to the landscape yards," he says, adding that they are fortunate to have four very large mulch yards—doing up to 5 million bags per year—that take their material. At the mulcher’s operation, they regrind down through a 2-inch screen to produce an appropriate product.
If the end product is a mulch or mulch-like material, the recycler is more likely to opt for a grinder. Grinders are limited by the size of the material they can process. However, in most regions of the country, the determination on whether to chip or to grind is dictated by the local market. In the upper Northeast or the Pacific Northwest, producing boiler fuel is a major market. In a lot of urban areas, like Charlotte, N.C., or Atlanta, mulch is a more viable end product.
An operator with an energy contract will be using a chipper and grinder to handle stumps. Foote says one horizontal grinder will handle long trees well.
A home-designed, homemade system serves Recovery1 Inc., Tacoma, Wash. well. A mixed C&D recycler, the company sees all manner of materials through its operation. "Here in the Northwest, we get some pretty big stumps. But I’ve yet to see one I can’t handle," says Terry Gillis, general manager of the operation.
Recovery1 is a stationary processing facility, accepting materials from C&D processors. About nine years ago, the company put together a shear and grapple system on a Caterpillar 330BL excavator. "Even with the biggest stumps, we can split them and then process them," Gillis says.
Normally the company looks for a 3-inch-minus product. But not all of the land clearing debris that shows up meets that specification, thus the need for the special unit.
Where the situation gets dicey, Gillis continues, is when homeowners bring in material. Often they try to bring in grass clippings and similar small material. "We are not a mulching operation," he has to tell them.
The chipped material generally comes from a typical new construction site. The contractor brings the material to Recovery1, it is weighed, the wood is dumped and a tipping fee collected.
"Most of our material goes to boiler feed," Gillis says. They have a potential market for pulp wood-to-paper, but that has to be 100 percent post-consumer material, and C&D does not meet that standard.
BUYING A UNIT
Just as boxers must jab and defend, C&D recyclers must consider initial purchase cost on debris handling equipment and the ongoing operating cost. The latter, over a lifetime, will probably outstrip the former.
"Buy your machine based on the number of cubic yards per hour or per week that you will process," advises Lint. "Or, buy on the tonnage that you will be handling."
The size of the chipper or grinder a recycler should use will depend on the job. He may estimate 100,000 cubic yards will be processed on-site in a 30-day period. Or, he might need to do a certain number of yards per day to keep up with the land clearing.
Whatever the case, buying a machine that is fitted to the job and local conditions is critical. In crunch times, like after a storm, that can be a challenge.
Large-scale operators have feller-bunchers that cut and lay down trees on site. An excavator will skid them over to the chipper as whole trees.
In some cases, the chipper will discharge the chips onto the ground. In others, the recycler will use a blower to fill an open-top truck.
Foote’s advice to C&D recyclers—to be sure to stay close to a dealer who stocks parts and has good mechanics—holds true for any operator.
Lyman recommends considering a two-step process for stationary grinds. "In high-volume stump grinding, a nice way to get a good product is with a screening process," he says.
First, run the big material through a slow-speed shredder. "Take that big, gnarly stump and knock it down," he says. The end result should be material in the 24-inch-minus range.
Next, put a screen after the pre-shredder and screen out all of the small material. If the load is clean, you will recover higher-value small material without further processing. If the load is dirty—stumps often have a lot of dirt and stone attached—the screening will get rid of most of the nuisance material.
Fitzgerald says his company, and other local land clearers, have lost business because of dirty grinds that were offered by one or two land clearers. "There are boiler plants around here. But one dirty grinding gives all land clearing a bad name," he says. These days, according to Fitzgerald, the boiler plants turn up their noses at anything associated with land clearing as a result of those bad experiences.
Even for mulch, Fitzgerald makes sure to shear through the root mass and break down down the stumps to get rocks and other unwanted material out of the root balls. "The shears work very well at that," he says.
Lyman says a disk screen or vibrating screen is usually best. Since they sell all types of screens, he has no favorite but says it depends on the needs of the C&D recycler.
Lastly, Lyman advises recyclers to use a vertical feed grinder to produce a good 3-inch-minus product. While a horizontal grinder certainly will work, he recommends a vertical grinder. "Gravity is an energy-effective feed mechanism," he says.
"A two-step system has a much lower initial cost and much lower costs from an operating point of view," Lyman says. "Your production rate will go up and your maintenance costs will go down."
If a multi-step process is not feasible, Foote recommends a hammermill grinder for tough feed material rather than a chipper with sharp knives. "Those hammers are much more tolerant of debris than knives," he notes.
"But it still is up to the end product whether to grind or to chip. If you’re producing mulch or composting material, then grind. If you are producing chips for an energy plant, then bring in the chipper," Foote says. That way, both your equipment and your customers will be back to go another round. C&DR
The author is a contributing editor to C&DR and can be contacted at firstname.lastname@example.org.