Nowadays it’s often good to think small. Mini excavators are taskmasters on job sites where there’s less room to roam. With urban density and infrastructure growth, prime building sites are scarce. The mini excavator is a welcome alternative when faced with obstacles such as restricted access, lack of space, sloping terrain, heavy traffic, and more, or when taking on jobs once handled by the good-old pick, shovel, and wheelbarrow. Combined with a wide array of attachments, the mini excavator is a versatile performer. Importantly, its reduced (or even zero) tail swing allows the mini to boldly go where no full-size excavator has gone before.
On Top-Down Projects
The mini excavator is a creative alternative, especially amid today’s trend toward a more piece-by-piece, controlled demolition approach. Mini excavators are small enough for interior work and light enough for the top-down demolition project. For example, picture more than a dozen mini excavators being hoisted to a demolition job at the very top of a 28-story hotel adjacent to New York’s Museum of Modern Art. Several years back, the old hotel was razed to make way for the museum’s expansion. Compact excavators, equipped with hammers, were used to break up concrete slabs and masonry walls. Elevator shafts were converted to chutes for removal of the material, which amounted to more than 20 truckloads of construction-and-demolition debris per day. As each floor was demolished, the compact units were lowered to the floor below by means of block and tackle. The entire demolition job was planned to minimize any vibration to the museum next door, preventing damage to its many pieces of priceless art. In this case, compact equipment was a safe yet efficient solution.
On Bottom-Up Projects
Much like “controlled” demolition, sensitive restoration and renovation applications are ideal for the mini excavator. When a historic pavilion was being restored in the community of Norwood Young America, MN, compact equipment was key to the project’s success. This all-volunteer project would require much assistance from the local community and from larger businesses, such as Bobcat Co., which worked with a local dealer to supply the compact units.
A primary goal was placing the load-bearing points of the building on permanent piers below the pavilion. The 134-foot by 40-foot building needed to be lifted to allow for the excavation below and the preparation for a new foundation. Bobcat dealer Paul Lano, co-owner of Lano Equipment of Norwood, provided two Bobcat compact track loaders and a 430 compact excavator for the job.
“In order to raise the building, it needed two 7-foot-deep and 140-foot-long trenches, one left and one right of center,” says Lano, explaining that the long I-beams would go through these trenches to raise the building.
Challenging soil composition (clay-based soil with pockets of water) made track loaders a must on the project. The Bobcat T250 and T300 track loaders worked in tandem to excavate the trenches underneath the pavilion. “We don’t believe there was any other machine that would have been able to work in these soil conditions. Wheeled machines [skid-steer loaders] would just not have been able to do it,” says Lano, adding that the height requirements prohibited the use of a crawler tractor.
In addition to the two long I-beams running underneath the pavilion, a dozen 55-foot cross beams were placed above the floor, adjacent to the load-bearing points of the building. These cross beams and the two I-beams were critical to lifting the pavilion off its old foundation.
Thirty new support structures were built to serve as the building’s foundation. The Bobcat 430 compact excavator was used to dig the pilot holes for these supports. “The compact excavator was the answer to getting around the beams supporting the building and to digging the new pilot holes,” says Lano.
Another restoration project accessing the mini excavator was that of a Saratoga, CA–based elementary school that required an earthquake retrofit. Frank Parker, owner of All Terrain Backhoe Service, says he purchased a Kubota K008-3 mini excavator to tackle this tough renovation challenge. Originally built in the 1920s, the building exhibited a style and charm that the community wished to preserve. Parker was faced with laying a new foundation under the school. Since it was built on a slope, Parker was able to place the mini excavator underneath the school to dig out dirt and other materials in preparation for the foundation pour. “It beat using shovels and it sure saved us time and labor. The job had extremely tight access and the Kubota K008-3 did the job well.” Due to its compact design, Parker was also able to use the machine to dig new plumbing trenches inside the school’s bathrooms.
In Tight Residential Areas
Glenn Fielden, a Manitoba-based contractor, specializes in excavation jobs that include swimming pools, site preparation, residential footings, and basement work. He chose the Caterpillar 304 CR mini hydraulic excavator for its compact radius aspect, which is particularly valuable in the tight residential areas in which he constantly works. He remembers days not long ago when the basic excavation of a pool took 12 hours. With the compact radius, he’s shaved that time down to about eight hours. The rear of the machine can swing 360 degrees without extending beyond the track base of the machine. “I can park this machine in the tight spaces between the houses in the newer developments, dig, and then spin around with a full bucket and dump it right into my tandem. I don’t have to constantly watch behind me to see where the tail is going,” says Fielden.
Equipped with a long stick (which is about a foot longer than the standard stick), Fielden found the machine ideally suited to his pool and excavation needs. With the longer stick, he no longer has to move the machine down into the basin of the pool. The machine offers a digging depth of about 12 feet, and a reach of approximately 19 feet. The front-end blade, he says, offers exceptional stability while both digging deep and loading high.
On the Slopes
Dirtworks & Construction is a Tennessee-based retaining wall installer that recently completed a large, upscale project in the Tims Ford Lake area. The steep sloping properties lining the picturesque lake are home to some of the most luxurious residences in south-central Tennessee. The project included four different walls, each with 5 feet of exposed masonry block, which boasts natural extrusions, artistic arcs, recessed stairways, and in-wall lighting.
Limited access added to the complexity of the job. With only a 7.5-foot-wide path to traverse, compact units were the only option. The crew also needed to minimize any damage to the homeowners’ established landscaping.
The company chose a Mustang ME6002 compact excavator combined with a Mustang MTL25 track loader. Both could easily access the job site, and the low weight, low ground pressure, and rubber tracks on each machine helped prevent damage to a newly laid concrete driveway.
Because the project called for a steep slope to be terraced, excavation was a major part of the job. The crew used the ME6002 on the excavation, pairing the MTL25 with it for removal of the dirt. The company says the equipment delivered a significant payback—more than a 30% increase in productivity.
Leibold Irrigation, based in East Dubuque, IL, and Toledo, OH, is also a contractor that frequently tackles sloping terrain. The company installs irrigation at golf courses across the nation. One of its recent projects was at a nationally known golf course in Las Vegas where the company was hired to irrigate tee boxes and rough areas. Faced with the steep hills and hard, sun-baked soil common to the southwestern region, Leibold used three Vermeer compact excavators to dig into the hard ground, which was filled with caliche. Vermeer lawn plows and trenchers were used to install the main line of pipe and to pull the pipe through the sprinkler heads. Leibold credits the equipment with considerable time and labor savings.
Mini Advantages
Aside from the fact that mini excavators can squeeze into the smallest spaces, contractors are also choosing them for a number of additional benefits—less capital investment, labor savings, and much more. Lightweight mini excavators eliminate the need for special highway hauling permits and commercial drivers’ licenses. They require far less operator training time. And they’re small enough to fit on a pull-behind trailer and can be transported with pickup truck horsepower. For jobs where the heavy-hitting, full-size excavator is just way too big, the mini has many advantages.
Construction-industry writer Carol Wasson owns JCL Marketing & Communications Inc.
GEC
- January/February 2006
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