SonicSampDrill

Sonic Tooling

Lost Cone Installations

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Lost Cone Installations

Eijkelkamp SonicSampDrill developed a seismic drilling technique based on a lost cone, which is hammered or vibrated into place with a small-diameter casing. It is now the standard solution for shot hole drilling.

The problem with installing seismic explosives

In the past, installing seismic explosives resulted in cutting piles and disturbed soil surfaces left behind in the field and, even worse, penetration of impermeable layers allowing leakage and mixing of saline or contaminated water with clean aquifers or even flowing to the surface.

The Eijkelkamp SonicSampDrill solution: Seismic Drilling

To reduce the impact of the exploration work, Eijkelkamp SonicSampDrill developed a much neater technique, based on lost cones.

  • The first version was a narrow casing hammered down with a portable petrol powered hammer. Then came hydraulic top hammers.
  • Next we developed a soil anchor clipped on the explosive to increase field crew safety and further increase research integrity by holding the explosive at the target depth. A pre-formed bentonite cylinder is placed above the explosive cartridge, and the casing is filled with water (or air) to create back-pressure. The casing is then pulled out; leaving behind the cone, explosives and bentonite. Once the bentonite is hydrated and expanded (48-72 hrs) the explosives are detonated.

The CompactSonic drill heads

The most recent improvement is our CompactSonic drill head! Now, you can mount the sonic drill head on an all-in-one CompactSonic mast which allows a direct hook-up on a tractor. This CS-T mast vibrates down and also retrieves the casing, once it is loaded with explosives and bentonite. The Sonic vibrations create liquefaction of the soil surrounding cone and casing, which increases penetration speed significantly.

Working with these tractors improves your productivity. Pulling up the casing is no longer a problem. A tractor is extremely mobile and well accepted by farmers. The soil anchor and the bentonite seal improved working conditions and the quality of seismograms, by locking the charge in place and directing the explosive energy downward. Also, the bentonite seal solved the problem of aquifers leaking salt or polluted water to other aquifers or to the field surface. The superior efficiency of the CompactSonic allows seismic work to continue to be done beyond the growing season.

Safety

The seismic shothole tools and procedures are designed to prevent pulling up the explosive when extracting the drill casing. First, there is the geometry of the lost cone, assuring a minimum of friction when going down and a maximum of friction when the casing is pulled up, optimizing the chance that the cone stays down.

Second, the weight of the full length of bentonite plugs and water column pushing on the lost cone during extraction, plus the anchor mechanism on the explosive hold the charge in place. The vigorous sonic vibrations, only used during pulling up of the first section of casing, reduce the risk of a blocked cone to zero.

Hydraulic integrity and environmental aspects

After pulling up the casing, the bentonite will expand to seal the borehole left behind by the casing. After some 48-72 hours, the plugs are fully hydrated and expanded and prevent mixing of saturated zones. Even in brackish and seawater, the bentonite plug is an effective seal. The lost cones are cast iron; the most abundant mineral on earth.

For seismic research we supply three sizes of casings: GP63 mm, GP88 and GP100; all with lost cones.

Product

Application

Drill Shoes

Holds lost cone. Is twisted on lower casing

Drill Casings

GP63 casing connects drill head with lost cone

Adapters to Sonic spindle

Connects top of casing with drill head

Lost Cones

Plugs casing until retrieval

Anchors for explosives

Folds out during retrieval of casing; also preventing theft

Seismic catcher#

Connects explosive with lost cone (only for GP63)

Bentonite plugs

Swells after adding water, repairing penetrated impermeable soil layers

Loading rods for explosives

Can be used to position explosive in open borehole (or casing)

Road crossing poles

Allows crossing roads with temporary cables

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