DUTCH DRILLING and drilling equipment manufacturer Conrad-Staten has developed a new 'vibra-corer' with dredging and marine contractor HAM.
The P291 pneumatic corer can work in up to 30m of water, using a standard 3m barrel to recover 67mm diameter core up to 2.75m long in both clay and sand. Penetration rates are 1m to 1.5m/min in medium dense sand, 0.3m to 0.6m/min in dense sand and 0.9m to 1.1m/min in clay.
The equipment was used on a recent mineral exploration project off the coast of Brazil. Some 30 cores a day were taken, with 90% average recovery in sand and 60% to 70% in clay and peat. Results were so good, claimed the company, that it decided to test a 6m barrel (producing core up to 5.75m long), which produced comparable recoveries.