Geoprobe® FAQs

Geoprobe^® probing equipment has redefined the way sites are investigated in the Environmental Industry. In many areas of the country, Geoprobe^® brand machines and tools have displaced traditional drilling methods as the preferred mode of collecting subsurface samples. There are numerous reasons why Geoprobe^® direct push techniques have found such wide acceptance in the field. Among these reasons are the following:

• No cuttings are produced during the sampling process.
• Probing is fast: typical penetration rates are from 5 to 25 feet (2 to 8 m) per minute.
• Mobilization is quick and economical.
• The sampling process is fast; 20-40 sample locations per day.
• Probing machines are easy to operate and relatively simple to maintain.
• Probing tools create small diameter holes which minimize surface and subsurface disturbance.
• Geoprobe^® machines fold compactly and store in cargo vans or truck toppers where the unit and tools can be locked and secured.
• Geoprobe^® machines have lower capital costs and are more economical to operate than rotary drilling machines and the level of effort and labor required for Geoprobe^® machine operation is much less than for conventional drilling.
• Geoprobe^® machines can be used to sample subsurface media including soil, groundwater, and soil gas.  Geoprobe^® machines can also be used to retrieve geotechnical data via cone penetration testing.

Soil probing equipment is typically used for site investigations to depths of 30 to 60 feet (9 to 18 m) depending upon soil conditions. However, this range is elusive and constantly increasing as better probing equipment is produced. Geoprobe^® brand soil probing equipment has been used to depths exceeding 100 feet (30 m) in many areas of the United States and overseas.

• It's hydraulically powered either from a vehicle or an auxiliary engine.
• It uses static force and the dynamic percussion force of the GH40, GH60 or GH80 Soil Probing Hammer to advance small diameter sampling tools.
• It rearranges particles in the subsurface by application of weight and percussion to advance a tool string and produces no cuttings in the process.
• It can drill through surface pavements 12 inches (305 mm) or more in thickness and probes beneath them.
• It can be used for collecting soil cores, groundwater samples, and soil gas samples. A probing tool is also available to make continuous log of soil conductivity and probe penetration rates.

Direct Push machines "push" tools and sensors into the ground without the use of drilling to remove soil to make a path for the tool. A Geoprobe^® brand direct push machine relies on a relatively small amount of static (vehicle) weight combined with percussion as the energy for advancement of a tool string. Probing tools do not remove cuttings from the probe hole but depend on compression of soil or rearrangement of soil particles to permit advancement of the tool string.

• Streamline subsurface investigations
• Need for fewer permanent monitor wells
• Provide quick, multiple media and multiple depth sampling
• Lessen investigation derived waste (IDW) disposal headaches
• Acquire in situ chemical and physical data
• Use of less visually obtrusive equipment
• Minimal physical and chemical disturbance of the sample media
• High degree of sample integrity

Soil conditions determine sampling depths for Geoprobe^® machines, but typically they can collect samples from depths less than 50 feet, but some of our customers regularly sample to depths of 100 feet, and a few have sampled to nearly 200 feet. Direct Push (DP) applications are most applicable in unconsolidated sediments. Penetration is limited in semiconsolidated sediments and is generally not possible in consolidated formations. DP equipment may also be limited in unconsolidated sediments with high percentages of cobbles and boulders or soils high very high density (i.e., hard soil).

The wiring configuration of 12VDC outlet receptacles was changed on Geoprobe^® direct push machines beginning November 1, 2003. This change was made to conform to industry standards and allows connection of aftermarket accessories without concern of equipment damage.

The undersized cutting shoe for the Macro-Core^® Sampler takes a 0.125 in. smaller OD core, which allows room for the material to expand. Use a heavy duty liner which are harder for the soil to expand causing them to stick inside the MC sample tube. For the easiest solution, use our Hydraulic Liner Extruder.

• 60 in. MC Sample Tube
• 48 in. Sample Tube
• 36 in. Sample Tube
• 24 in. Sample Tube
• 1m Sample Tube

A discrete soil sampler is a closed sampling tool used to collect a soil sample from a prescribed or distinct interval. The inside of the sampler is not exposed and has minimal exposure to the subsurface environment until the sampler reaches the prescribed depth. These samplers are sometimes called closed or closed tube samplers.

A non-discrete soil sampler is an open sampling tool used to collect samples continuously. The inside of the sampler is exposed to the subsurface environment while it is advanced to the sample interval. These samplers are sometimes referred to as open or open tube or continuous samplers. Read more about our soil samplers...

Dual tube sampling gets its name from the fact that two sets of rods are used to collect soil cores. The outer rods receive the driving force from the Geoprobe^® machine and provide a sealed hole from which soil samples may be recovered without the threat of cross contamination or cave-in. The second set of rods are placed in the outer rods and hold a sampler in place as the outer rod is driven the sample interval. The inner rods are then retracted to retrieve the soil core.

Grab samplers are usually installed on a temporary basis to collect groundwater samples, hydrogeologic data, and then removed from the subsurface. The samplers are installed, a sample is collected, hydrogeologic tests may be completed, and then the sampler is removed. Two types of grab samplers are commonly used with DP machines, non-discrete or unprotected screen, and discrete or protected screen.

Because the sampling section of the non-discrete groundwater sampler is not protected or sealed, this sampler should only be used where cross contamination from overlying materials is not a concern.

Discrete groundwater samplers are driven to the sample interval, then o-rings, a protective tube/sheath, and an expendable point provide a water-tight seal.

In situ analysis makes use of technologies or methodologies that do not require collection of samples. The instrument is brought into contact with the media to be sampled in place; without removal of the medium and placement in containers. Ex situ analysis makes use of technologies or methodologies that require some type of physical collection of samples, the sample must be taken to the instrument for analysis.

Absolutely! During subsurface investigations you will probably collect groundwater for chemical analysis, determine some basic hydrogeologic parameters (hydraulic conductivity, permeability, etc.) and/or take static water levels. This is usually referred to as characterizing the groundwater. The type of Geoprobe^® groundwater sampler will vary from temporary installation to collect grab samples to monitoring wells designed for permanent installation and long-term monitoring.

We use a 20/40 mesh environmental silica sand.

Yes, we have three options for the SP16:

• GW1520 stainless steel wire wound screen
• GW1530 PVC 10 slot screen
• 16089 PVC expendable 10 slot screen

The earlier the better. Orders received by 4 p.m. Central Time are usually sent out the same day if stock permits. For large quantities of one item, it's best to call ahead of time to make sure our inventory can accommodate your needs.

We accept most major credit cards or will send your order COD, usually the same day the order is placed. Mailing or faxing us a copy of your company letterhead with the proper billing and shipping information speeds up the process. It's also best to have a contact name at your company who wants to receive tooling and price updates. Contact us today to place your order.

You are always welcome to visit us at Geoprobe^® Headquarters in Salina, KS. If you come to HQ, we provide most training services at no charge.

Right in the middle of Kansas, 1.5 hour drive north of Wichita and a 3 hour drive west of Kansas City. This is where the wheat grows tall and the sky meets an endless horizon.  Come visit us!