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Vibracoring Examples of CSA International's Marine Field Operations Services:
Vibracoring CSA International has assembled and developed a highly portable and cost-effective vibracoring system. CSA maintains and operates it's vibracoring system to collect shallow water (<20 m or <66 ft depth) undisturbed core samples that are a maximum of 5 m (16.5 ft) in length. CSA International has utilized in-house vibracoring systems since 1980. CSA International's present system has been through several evolutions. The present vibracoring system uses a 23-kg (50-lb) pneumatic head consisting of a high-speed piston system that drives the variable length core barrel through seafloor sediments. With this system, optimal penetrating characteristics are attained using 7.5-cm (3-in.) diameter thin wall core tube made of either clear acetyl butyrate (plastic), aluminum, or stainless steel. The platform from which samples are collected typically is CSA International's 25-ft trailerable outboard-motor-powered work barge equipped with a 15-ft high A-Frame, coring winch, compressor, and multi-point anchoring capability. CSA International has extensive experience collecting 2.5- to 3-m (8- to 10-ft) core samples along the coastlines of the Gulf of Mexico, Florida, Georgia, South Carolina, Puerto Rico, and the British Virgin Islands. CSA International has had excellent success with coring unconsolidated and coarse grain size sediments, with recovery ratios routinely in the 85% to 95% range and excellent sample quality. These high recovery ratios occur before hitting any consolidated formations (i.e., Pleistocene formations) and depend upon the thickness of the sediments above these formations. Some doming of the sediments can occur and should be taken into account during core analyses. CSA International has collected numerous vibracores during a 3-yr field sampling program for the Mississippi-Alabama Sea Grant Consortium. The system has been used regularly to collect core samples for physical, chemical (pesticides, hydrocarbons, and trace metals), and bioassay analyses under delivery order contracts for the U.S. Army Corps of Engineers. CSA International's vibracoring system also has been used extensively to delineate suitable sand resource areas.
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