Crushing and screening attachments are providing flexibility and cost savings for demolition contractors and C&D recyclers.
Many technical reasons may cause a C&D recycler or demolition contractor to use an attachment rather than a stationary plant for crushing and screening debris. However, Kim Lenker, owner of Lenker’s Excavating, Enola, Pennsylvania, has a different reason.
“One of the biggest things is that we don’t get into the permitting requirements with the DEP (Pennsylvania Department of Environmental Protection) that you would with a big, stationary plant,” Lenker says.
He also finds that an attachment-based unit makes his crew more nimble. “We do a lot of specialty work,” Lenker continues. “We can move in and out faster than you would if you had to set up a plant. Within a half-hour, we can get onto a site and be ready to crush again,” he says.
“It’s about flexibility. The right attachment is one more tool in your toolbox,” says Curtis Lindsey, president of Lindsey Construction, Houston. He compares a basic excavator to a tool belt with just a screwdriver. Contractors need crescent wrenches and socket sets to get any job done.
Lindsey says attachment technology has come a long way in just the past 10 to 15 years. “There is so much more flexibility on excavators with all the buckets, grapples and other attachments,” he observes.
Often a demolition site will require a pile of rock to be crushed for reuse as base material. The complexity of installing a track system goes beyond the scope of the job. Meanwhile, equipment such as skid steers and bucket loaders are all over the construction zone. Why not hook up a C&D attachment to equipment already on-site?
“Attachments let you take an existing excavator and turn it into a more versatile tool,” Lindsey explains. “You have the flexibility to move from site to site and mobilize quicker to small jobs.”
For small job sites, this is a good strategy, says William Pratt, marketing director with Rockland Manufacturing, Bedford, Pennsylvania. Rockland handles the Austrian-built Hartl Crusher.
“If you need 600 tons per hour production, you’re not going to get that,” Pratt says, adding, “but for smaller jobs, attachments are perfect.”
Larry Giberson, owner of Giberson Enterprises, Shamong, New Jersey, says, “The smaller the job the better the savings. On-site recycling and processing with attachments save a lot of cost, downtime and reuse of materials.”
Attachment versus stationary
Martin Hartl of Hartl Crusher offers a check-list of reasons a C&D recycler should consider attachments:
- Less investment cost;
- Less operating cost: there is only one operator, one excavator, one transport;
- Less maintenance and easy setup;
- Less downtime in case of blockages, easy service and maintenance as no complicated hydraulic and electric system is needed;
- Less cost to crush per ton;
- Less transport cost for the crusher;
- No permits needed; and
- Long rebar concrete is no problem with an attachment‘s straight passage...a feature not possible with standard mobile equipment.
A misconception about attachments is that they don’t offer the throughput of a crushing plant. But that isn’t always the case. In fact, the largest machine that Rockland offers will process up to 120 tons per hour—quite comparable to a small track crusher. There also is a huge cost savings, Pratt notes.
“Look at the cost,” Pratt says. A bucket-mounted attachment with that capacity will run about $90,000 versus $300,000 for a track crusher, he says.
MB America, Reno, Nevada, notes there are times when an attachment can be used to prepare the material for final processing.
Lenker finds cost savings in a different area: labor. “With an attachment on a loader, you can drive to different spots on the site. One guy can run around and work the piles right in place,” he says.
For that reason, Jesse Allen of the marketing department of Allu Group, Teterboro, New Jersey, says the company works with recycling centers that use their equipment for reducing material size, separating heavy materials from light-weight materials and screening smaller material from larger sized material.
“When concrete is too big it will get stuck in the stationary crusher and then the contractor loses hours on the job site trying to fix the jam,” says Mike Meehan, Midwest regional manager in Okada’s Fort Wayne, Indiana, branch. He asserts attachments will better handle such situations.
Manufacturers offer recyclers an array of choices from rotary crusher buckets to impact crusher buckets to the ram-style crusher buckets. Rotary crushers, Giberson says, work well in soft through medium-hard jobs such as asphalt, concrete and limestone. Jaw crushers perform well in medium to hard material such as concrete and hard rock.
The scenario is similar with screeners. There are four main styles: disc, basket, riddling and flipping. Screeners are used for anything from powder, sand and mulch to topsoil and similar debris.
Dirt, brick and concrete are well-suited to screening applications.
Martin Hartl of Hartl Crusher says attachments should be used when crushing debris on site. “The end product can be immediately reused, for example, as sub-base material, eliminating any hauling and disposing costs,“ he points out.
Attachments and stationary units are not necessarily mutually exclusive, according to Allen. He says many contractors feed their stationary crushers and/or screeners with an Allu attachment to make their stationary machine more productive or save their stationary machine from damage.
When deciding on an attachment, Giberson recommends buying the excavator’s auxiliary hydraulics. He says some attachment retailers do not explain this. “Attachments can basically only be as powerful or perform as well as the machine carrying them,” he remarks.
Rebar is another concern. “Rebar can be a major safety problem on demolition sites,” Meehan says. Instead of paying a cleanup team to do the dangerous work, Okada’s crushers can safely compact rebar into a small space to be broken down.
Wear and tear
Crushing and screening attachments don’t have the same upkeep that a mobile crushing and screening plant might have, but there is a trade-off. “We don’t get the tons per hour you might get with a big plant, but we don’t have the maintenance expenses, either,” Lenker says.
An attachment like the Hartl unit has five wear parts with the crushing jaws taking the brunt of the wear. The toggle seat and other wear plates make up the rest of the replaceable parts.
When well taken care of, attachments are not major contributors to downtime. “You can get 4,000 to 6,000 hours out of a set of crushing jaws,” Pratt says. “It’s a very low maintenance item.”
“I think the maintenance with an attachment and a stationary unit will be comparable,” Lindsey says, noting that harder rock usually means more wear.
“Dirt is the enemy of a crusher. Keep dirt out,” Lindsey suggests.
Meehan says Okada’s TMB screens remove dirt to stop clogging of crushers and they keep the dirt out of the final recycled product. The screens are ideal for preparing the recycled material for the crushing phase, he adds.
“All equipment needs wear parts but on attachments it is way less than with a plant,” Giberson says.
Meehan agrees, saying the only time screens need to be replaced is when the job application changes.
MB America recommends stocking the belt drive, threaded rod, tension spring and the silent block. Changes depend on how often the crusher operates and the material crushed.
Lenker Excavating uses a Hartl 950 and has more than 5,000 tons processed with the original set of jaws. “I haven’t changed jaws yet and the jaws really are not showing wear,” Lenker says.
“Other than weekly greasing, the replaceable wear hammers on the processing drums is the primary replacement part,” Allen says, adding that the parts are inexpensive to change out.
He estimates an Allu worth $50,000 will cost the owner approximately $1,700 to change wear hammers.
“Change frequency depends on the abrasiveness of the material being processed,” Allen says. For example, a topsoil screener may not change wear hammers for five years while an asphalt contractor may replace wear hammers twice a year.
The range of materials attachments will handle is almost as endless and varied as the demolition and C&D recycling projects underway across the nation: rock, sand, salt, bark, compost, topsoil, slab concrete, asphalt, coal, slag, limestone, landfill waste, roofing material, forestry, mulch, shingles, ice, gypsum board, wood, snow, coal and bricks, and even more materials.
Making the switch
“Changing one attachment to another is as simple as knocking the pins out and putting the pins back in the new attachment,” Meehan says.
“Properly set up, you could switch attachments in under one minute with new technology,” Giberson says. Realistically, he concedes his customers take about 10 to 15 minutes to swap out different attachments.
Of course, it depends on the type of coupler or hitch installed on the bucket and hoses. MB America says that with a quick coupler the job is done in five to 10 minutes.
Lindsey, who operates Giberson equipment, says it is no more difficult than putting on any other attachment. “There is no setup. There are just the pins and the hydraulics for any attachment,” Lindsey says. “The change-over takes a half-hour or so.”
After a sale, Giberson says he personally gets on a plane and meets the equipment at its final destination. There, he will assist with the hookup and operator training. “To me a customer spending $40,000 to $100,000 deserves this kind of attention and service,” he states.
The same holds true at Allu, where field personnel visit each purchaser to determine their needs and select a screening/crushing size to best fit those needs. While units come in six different screening and/or crushing sizes, they each screen or crush one size.
Once up and running, processing speed is controlled by the throttle of the base machine for the attachments. This is ruled by the hydraulic flow and pressure to the machine.
While mobile crushing and screening plants still have a place in the market, in the right environment, attachments that can work at lower costs and be easily moved around are earning a place in many C&D recycling and demolition applications.
The author is a contributing editor to Construction & Demolition Recycling based in the Cleveland area. He can be contacted at firstname.lastname@example.org.