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"The Geoprobe® 66 series track machine with the drop hammer has allowed us to complete work we typically would have used our skid rigs for." -- Chris DeAngelis, Connecticut Test Borings LLC, Seymour, CT

Geoprobe® Track Machines and the DH100 Drop Hammer make a great team. Customers have found the track machine to be highly productive in both shallow and deep sampling venues. The machine's small footprint enables it to readily negotiate in tight, confining work areas and on offroad, rugged terrain. Adding the drop hammer to the machine's configuration makes the machine uniquely flexible to switch from environmental to geotechnical work with little time and effort. Environmental work, including augering and monitoring well installation, are not disrupted with the drop hammer on the machine.

Standard Penetration Tests (SPT) are demonstrated using the DH100 Automatic Drop Hammer, mounted here on a Geoprobe Model 7730DT.

Victor Rotunda, Geoprobe® Customer Service, demonstrates the features of the DH100 Automatic Drop Hammer for customers attending a recent Field Days event in New Jersey. With over 25 years' experience in the drilling industry, Victor shares his knowledge with co-workers on why the Auto Drop Hammer (DH66 model shown here) is a great tool for working with shallow borings.

The days when you had to choose a machine based on whether you wanted to do environmental or geotechnical work are fading fast. Now you can do both.

• Need SPT blow counts for your customer? Use the Geoprobe® DH100 automatic hammer with your hollow stem augers or with the specially designed dual tube system by Geoprobe® Systems.
• Going to a job where you won't need the automatic hammer? No problem. A couple of minutes is all it takes to remove it from your machine, or you can swing and secure the drop hammer away from your work spaces.

The Geoprobe® DH100 Automatic Drop Hammer is an effective way to collect Standard Penetration Test (SPT) blow counts with your Geoprobe® machine.

SPT BLOW COUNT consists of:

1. Using a 140 lb. (64 kg) driving mass falling free from a height of 30 in. (762 mm)...
2. Driving the standard split spoon sampler a distance of 18 in. (457 mm) into the soil, and...
3. Counting the number of blows (N) to drive the sampler 12 in. (6 in. plus 6 in.) [152 mm plus 152 mm].

The hammer is powered through the auxiliary hydraulics on 66 and 77 Series Machines and is lifted into position using the probing cylinder. The inconsistency that has historically been a problem for the SPT test is minimized with the repeatable, accurate function of this hammer. The 140-pound weight has a 30-inch free fall before making contact with the anvil so every test is performed the same. And safety was a prime consideration during the development of this tool, so all moving parts and impact surfaces are enclosed in a steel housing.

DH100 Automatic Drop Hammer Features:

• Easy on / Easy off design!
• Conforms to ASTM Standards D1586-99.
• Operates from auxiliary hydraulics.
• Consistent results with no human error.
• No cables or ropes needed for operation.
• All moving hammer components are enclosed for operator safety.
• Hammer cannot be “dry fired” (must be on a rod string) or fired in the horizontal position foroperator safety.
• Hammer swings over hollow stem augers...no need to reposition the whole machine.
• Operates at up to 60 blows per minute.
• Throw height can be adjusted within seconds.
• Use your Geoprobe® track machine for both environmental AND geotechnical projects.
• Used to perform Standard Penetration Test (SPT) which is the most common in situ geotechnical test in the U.S.
• SPT blow count results are used by engineers for obtaining strength and density properties of soil, designing foundations, and defining earthquake sensitive soils.
• Use the Geoprobe® SPT dual tube system with the automatic hammer for SPT testing.
• Mounts on most Geoprobe® 7730DT, 7720DT, and 6620DT machines with a minimum of initial field modification.

The Geoprobe DH100 Automatic Drop Hammer locks in position for easy transport, then easily unlocks and pivots into place for use...without the need to reposition the entire machine.