Geosonda, a Belgian drilling company, recently completed a sediment sampling project on the Ghent-Terneuzen Canal. The project was carried out from a barge using an Eijkelkamp SonicSampDrill SRS ML SmallRotoSonic drill with AquaLock 70 sampling system.
"Geosonda is active in soil research for environmental, geotechnical, and archaeology-related projects," says Hans Jacobs, team manager at Geosonda's drilling department, who led the project. "During this project, we worked from a barge in Ghent-Zelzate to take sediment samples from the Ghent-Terneuzen Canal.
"The layer of sand just below the silt layer is very important in this case, because the canal will be deepened to a certain depth. However, before the work can start, the purpose of the material to be removed had to be investigated. In addition, this research helps to determine the correct way to excavate or dredge the riverbed.
"An engineering firm asked us to take samples from the sediment. We sampled five metres into these fine river sediments using the AquaLock 70 system."
The patented AquaLock system is a piston sampler, specially developed for alluvial deposits and soft sediments. Although these formations are easy to drill through, it is often difficult to take high-quality samples from them. This is especially true for hydrogeology, such as heaving sands, tailings, delta and maritime formations, etc.
The AquaLock is a piston sonic proof sampler. This piston allows discrete or continues samples as it locks the piston in the cutting shoe in place with water (aqualock) before sampling starts, therefore with continues sampling no casing is needed as the blocked piston will displace a collapsed hole.
Other unique features of the AquaLock are that the piston creates a vacuum on the sample, in case of fine, wet or even slurrified materials this is an advantage for its sample recovery and integrity.
Using AquaLock creates a vacuum on the sample which is advantageous for fine, wet or even slurrified materials
Geosonda saw the absolute sense in using the AquaLock and its sonic drilling system. "Geosonda has several drilling techniques in-house, but sonic delivers the best quality and full recovery in these softer formations time after time. These good-quality samples ensure we can make a very accurate description, which is very important for an in-depth study of the water. This allows us to formulate fantastic, detailed descriptions and take high-quality sediment samples," explains Jacobs.
"Looking back at this project, I am very satisfied. We finished faster than we thought, and we worked very effectively with the crew on the pontoon. I expect that we will carry out many more of these kinds of projects in the future, especially in combination with this SRS-ML and the AquaLock in the Eijkelkamp SonicSampDrill. It's a technique that allows you to make a quick screening and get high-quality samples."
