III. MINING: SITE SELECTION, TECHNOLOGY AND PROCESSING 
Mine Srre SELEection 
Geophysical and topographic data are necessary before a mining site 
can be selected (Fig. 7). The method of mining will determine, to a 
limited extent, the water depth and bottom conditions necessary for 
the mining system to work. For example, a nodule-collecting device 
mounted on a tracked vehicle must operate on a firmer bottom than 
that needed for a neutrally buoyant rake-type collection head. Both 
of these methods can probably operate in an area of greater topo- 
graphic variation than the continuous line bucket (CLB) dredge. 
About 25 factors are involved in calculations to determine the eco- 
nomic value of a ferromanganese nodule deposit.' In addition to the 
water depth, bottom topography, and physical characteristics of the 
sediment, other important criteria are the concentration of the nod- 
ules, their size, uniformity, metal content, distance to port or process 
facility, and weather in the deposit area. Since the nodule concentra- 
tion per unit area of the sea floor and their metal content may vary 
within a prospective mine site, the site must be thoroughly sampled 
to ensure it can support a mining operation. Free-fall grab samplers, 
dredges, and television cameras are commonly used to evaluate the 
economic potential of a mining area (Fig. 7). 
1Mero, J. L. Potenial economic value of ocean-floor manganese nodule deposits. In Ferro- 
manganese Deposits on the Ocean Floor, Horn, D. R., ed., IDOE, National Science Founda- 
tion, Washington, D.C., 1972: 191-208. 
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