For contractors in Alaska, nothing comes easily. Beyond the harsh site and the weather conditions that continually put man and machine through the stiffest of tests, the materials themselves can be hard to come by.
For more than 25 years, Osborne Construction Company has specialized in complex and challenging projects, often in remote locations; that is, projects that require extensive preplanning and the ability to coordinate and manage difficult logistical issues. Finding a piece of equipment that makes the company’s job easier and one that can be used on each of their jobs helps that coordination and logistical planning go much more smoothly.
After using the ALLU D-Series DH4-27/60 screener crusher attachment for a job in 2010, Osborne went to ConExpo-Con/AGG 2011 and purchased one from ALLU Group, Inc. to attach to its 66 ton (60 t) John Deere 600C LC excavator.
“To date we’ve already used the ALLU attachment on three job sites and are getting ready to use it on a landfill job coming up,” said Don May, civil manager of Osborne Construction Company.
“At each job site it has helped us overcome challenges quickly to get the job done on schedule. One of the advantages of the ALLU screener crusher is that you don’t have to set up a big operation for screening and loading. We just attach the ALLU and get the job done. We were direct-loading 40 ton artic trucks on one of the jobs and were getting 300 to 360 ton per hour of screened material. Having as small of a footprint as possible is important to us, and this one piece of equipment has allowed us to save extra production equipment and man-hours.”
Foundations For
Military Housing
Contracted to build 303 units of military housing in Joint Base Elmendorf-Richardson (JBER), Alaska, Osborne quickly discovered that the on-site material they were using under the concrete slab contained cobbles (called “big bones”), which are rocks that are generally 2.5 to 15 in. (6.4 to 38 cm) in diameter, in the raw material. Osborne built the previous housing phase 2 near the site in 2004 to 2006.
“On the Phase 2 we ran into poor concrete yield, 15 to 20 percent off from theoretical yield projections because the cobbles were causing the edges of the areas excavated for the thickened edge slab of the slab to collapse. For phase 3 we considered using more concrete but it was much cheaper to screen the top three feet of under slab material,” said May.
They started off screening 140,000 yds. (128,016 m) of minus 2.5-inch with an ALLU screener crusher attachment rejecting cobbles ranging from 2.5-in. (6.4 cm) all the way up to 15-in. (38 cm).
To keep material in spec and a good foundation quality, Osborne brought in the ALLU screener crusher attachment to screen the cobble material for the slabs.
“Once we screened the bones, the yields came back to within a couple of percent of what the theoretical yield projected. We had great success not having the bigger rock there.”
In addition to saving money using the on-site material, they were also able to continue on schedule with the job because the cobbles were being used for construction roads and in the waste fills to keep the trucks from getting stuck in the mud.
Railroad Extension
While building a railroad extension in September of 2012, the Osborne crew was using a ripper bucket on the John Deere 600C LC loosening to a depth of 6 ft. (1.8 m) for a length of about 3,000 ft. (914 m) after they ran into frozen material. “The material made spec, but it was full of frozen chunks,” said May. “Normally all the material would have been hauled off and replaced. Instead, we ran the material through the ALLU attachment, screened off the big stuff and reused the material in place. Everybody was really happy.”
Specializing in complex and challenging projects requires extensive preplanning and the ability to coordinate and manage difficult logistical issues. Finding a piece of equipment that makes the company’s job easier and one that can be used on a variety of jobs makes that preplanning go much more smoothly.
“The ALLU attachment fits this criteria. At each job site it has helped us overcome challenges quickly to get the job done on schedule without setting up a big operation. I have no doubt it is a piece of equipment that will be frequenting our upcoming projects,” said May.
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