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Rachel E. Dunham

Publications and source records attributed to Rachel E. Dunham.

2 recordsLinked to original sources
USGS2010

Seamounts and ferromanganese crusts within and near the U.S. EEZ off California - Data for RV Farnella cruise F7-87-SC

The purpose of this report is to present and briefly describe ship-board and laboratory data for a U.S. Geological Survey (USGS) research cruise aboard the RV Farnella that took place December 3-21, 1987 (cruise F7-87-SC). The purpose of the cruise was to survey seamounts and ferromanganese crusts within and near the U.S. Exclusive Economic Zone (EEZ) off California. Eight seamounts were studied - Rodriguez, San Marcos, Adam, Hoss, Little Joe, Ben, Flint, and Jasper. A geophysical survey of Jasper Seamount took place, but that seamount was not sampled; whereas Adam and Hoss Seamounts were sampled, but not surveyed with geophysics lines.

California↗
USGS2009

Seamount characteristics and mine-site model applied to exploration- and mining-lease-block selection for cobalt-rich ferromanganese crusts

Regulations are being developed through the International Seabed Authority (ISBA) for the exploration and mining of cobalt-rich ferromanganese crusts. This paper lays out geologic and geomorphologic criteria that can be used to determine the size and number of exploration and mine-site blocks that will be the focus of much discussion within the ISBA Council deliberations. The surface areas of 155 volcanic edifices in the central equatorial Pacific were measured and used to develop a mine-site model. The mine-site model considers areas above 2,500 m water depth as permissive, and narrows the general area available for exploration and mining to 20% of that permissive area. It is calculated that about eighteen 100 km 2 explora-tion blocks, each composed of five 20km 2 contiguous sub-blocks, would be adequate to identify a 260 km 2 20-year-mine site; the mine site would be composed of thirteen of the 20km 2 sub-blocks. In this hypothetical example, the 260 km 2 mine site would be spread over four volcanic edifices and comprise 3.7% of the permissive area of the four edifices and 0.01% of the total area of those four edifices. The eighteen 100km 2 exploration blocks would be selected from a limited geographic area. That confinement area is defined as having a long dimension of not more than 1,000 km and an area of not more than 300,000 km 2 .

Marine Georesources and Geotechnology↗