The fuel efficiency of tub grinders versus horizontal grinders has long been a subject of debate. During a recent demonstration processing green waste, an unnamed enclosed tub grinder processed material at a rate of $11 per hour less than a Beast horizontal grinder. However, as Maryland Environmental Services (MES) found out, there is more to the story.
“It’s a common misconception that a tub grinder is more fuel efficient than a horizontal grinder,” explains Chad Cavolo, Mid-Atlantic field representative for Bandit Industries. “The Beast (horizontal grinder) may consume more fuel per hour, but it will process and will produce far more material.
"In reality,” he adds, “The fuel and operating cost per ton is much less with a Beast horizontal grinder than with a tub.”
Cavolo first caught wind that MES was looking to purchase a new grinder during a conversation with a local tree service who was utilizing the Montgomery County Organics services, which MES operates under a state contract. “When we heard MES was looking into getting a new grinder, we jumped at the chance to show them what the Beast could do.”
Nanci Koerting, MES’ project manager for Montgomery County Organics Department, said, “We had heard of the Beast, but it had been years since we’d seen one run. We really hoped it would work.”
And work, it did. Since acquiring the Beast, MES says they’ve reduced their fuel cost per cubic yard from 11 cents with the tub grinder to 9 cents with the Beast; they’ve seen an increase in volume; and have increased their production from 252 yards per hour with the tub to 430 yards per hour with the Beast – all of which have led to some extensive annual cost savings.
“Since we began grinding with the Beast, we’ve experienced a 60 percent increase in volume, simply because we can process everything,” explains Koerting. “With only a tub grinder, we could not process all of the incoming material and had to use an outside contractor to remove it. With the Beast, we have been able to process everything that comes into the site. Huge logs, storm debris, stumps – there are a lot of things you simply can’t grind with a tub grinder that you have to pay to have hauled away. The Beast is so versatile that it has already paid for itself.”
MES manages municipal-owned facilities throughout Maryland. Koerting’s projects include a 55-acre yard trim compost facility and a homeowner drop-off and organics pre-processing facility located in Montgomery County, Maryland.
“One of our primary concerns is always safety because of our close proximity to other operations,” said Koerting. “Everyone was cautious about trying something so different.” However, their fears proved to be unfounded.
“We have found the horizontal arrangement to be very compatible with the location, and our experience has been that it tends to be safer than an enclosed tub with regard to throwing material,” Koerting reports. “We process a huge volume of material in a very small area. There are people running around, customers coming in and out, dropping off material. It’s a fast-paced operation that could be potentially dangerous if not managed carefully.”
According to Bandit, not only has MES site been able to increase their intake volume, their hourly production, and also reduce their operating costs, but they’ve been able to do so with less downtime. “We don’t have room to set up a pre-screener, and it’s difficult to keep contamination down,” says Koerting. It is not uncommon for large metal contaminants, such as sledgehammers or other large objects, to be hidden in the material. “If its not found, that can be a whole day lost with an enclosed tub grinder. However, if it goes through the Beast, it’s not nearly as big of an issue.”
Says Andy Doyen, site manager, “When encountering contaminants with the Beast, bolt-on wear parts can be changed in a matter of minutes. With a tub grinder, significant amounts of time are often spent unloading the tub to get to the root of the problem, and it is not uncommon to experience increased downtime if subsequent repairs must be made.”
“On top of that, the enclosed tub takes such a long time to process large diameter trees and stumps,” says Doyen. “The Beast has them processed in no time. In fact, one of the first large logs we ran through the Beast was a massive seven-and-a-half foot long by five-foot in diameter tree – it was unbelievable.” The Model 4680T Beast has an opening of 45 by 60 inches – just wide enough to accept a five-foot diameter tree. (Footage can be found on YouTube by searching for key terms 4680 TRACK BANDIT BEAST. According to the time on the video, the log is devoured in less than a minute and a half.)
MES has also found savings by reducing the amount of handling required to process material. Their Beast Recycler is equipped with a track undercarriage, allowing them to take the unit to the material. “We knew right away that tracks would offer an added value,” says Koerting. “They are definitely a bonus.”
All of Bandit’s Beast Recyclers can be equipped with an optional Caterpillar track undercarriage, and they can be equipped with a number of options not available on many other grinders, such as a mulch colouring attachment, a thrower attachment for loading end-opening trailers, and a new patent-pending system for converting the grinder into a high-production chipper.
When it came down to it, MES determined that a self-propelled Beast horizontal grinder was the right machine for their site. “We thought that maybe we should stick to grinding the big stuff with the Beast, and the smaller material with the tub, because the client was concerned with capacity. But when you really looked at the numbers, Beast processed material at 9 cents per yard even when grinding nothing but large, hard to process material. With the enclosed tub, we were processing at 11 cents per yard and it could only process small material, easy to grind material. We discovered that we were better off running the Beast for everything, regardless of what we’re grinding.”
Koerting stressed that 100 percent of what is accepted at the Montgomery County Organics Site is recyclable. “Everything organic that comes in is recycled, reground and reincorporated. We have 0 percent waste. The Beast helps us accomplish that.”
“The Beast is a great machine,” says Koerting. “It’s given us bonus points with our client and shows them that we put a lot of time and analysis into our equipment recommendations.”
“The changes we’ve made here in the yard over the last three years have been personally rewarding, and have made the site much more efficient. It has also helped us realize our goal to turn out top-grade recycled end-products that are sought after in the marketplace,” says Koerting of MES’ role in Montgomery County’s operation. “It’s been a hugely positive experience.”
