Developing a Samplng System for Seabed Crust Deposits

Deep seabed rock dredging in areas with high relief

“…Continuous cutting was the goal for the modified design. Adequate normal force per unit length of contact is critical to successful cutting; but ease of handling restricts ultimate size and weight; therefore, the circular chain bag dredge was chosen as the base design (Schmidt et al, 1987). The detailed specifications were finalized during cutting tests using low-strength sand grout (7 MPa; 1,000 psi compressive strength), which was designed to simulate manganese crust by matching measured characteristics investigated in previous research .…”

Proceedings of the 1987 Exclusive Economic Zone symposium on mapping and research; planning for the next 10 years

“…Chain bag and box dredges permit a better assessment of surface mineral deposits. With improvements these may provide adequate sampling of hard deposits such as cobalt crusts (Schmidt and others, 1987). Although these techniques are not expensive in shallow water, they present considerable costs in deeper water where each sample or dredge haul may take 3 to 4 hours.…”