Seismic drills are designed to limit the impact of exploration work, Royal Eijkelkamp developed a much neater technique based on lost cones.
Royal Eijkelkamp has 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 boreholes.
The problem with installing seismic explosives
In the past, installing seismic explosives led to cutting piles and disturbed soil surfaces left in the field and, even worse, the penetration of impermeable layers allowing leakage and mixing of salt or contaminated water with clean aquifers or even flow to the surface.
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.
For seismic research we supply three sizes of casings.
Available variations
All with lost cones.
| Lost Cone Installations | |
|---|---|
| Three sizes of casings | GP63 mm (2.48 in), GP88 (3.46) and GP100 (3.94) |
| Lost cones | Plugs casing until retrieval |
| Anchors for explosives | Folds out during retrieval of casing; also preventing theft |
| 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) |
Looking for advice on your drilling project? Our specialist Greg is happy to help.
