16 
the pipe by the flow of water and air and deposited in the mining ship 
on the surface (Fig. 8). The ALP system is inherently more complex 
than a single or dual phase system. Several technica] difficulties have 
presented themselves. The amount and injection point of air, diameter 
of pipe, amount of water transported, and amount and size of solids 
transported each have narrow tolerance limits. For this reason, the 
system must be carefully adjusted to the conditions of each individual 
mining site. 
DEEPSEA VENTURES BOTTOM CRAWLER/ 
OCEAN MINING SYSTEM SEMISUBMERSI BLE 
SURFACE FACILITY 
CONCEPT 
ot ah Pivoted 
SSS 
Floating 
Pump Platform 
Capsule 
DUMP VALVE 
TRUSS HINGE CONNECTION 
& DEAD WEIGHT __ 
/ DEEP OCEAN 
MINING SYSTEM 
Courtesy of Veepsea Ventures 
Ficure 8.—Artist’s conception of the likely operation of three systems proposed 
for mining nodules. 
Source : United Nations, A/CONF.62/25 op. cit., p. 18. 
The bottom device or dredge head must be carefully designed to 
Screen out nodules that are too large to be transported by the air/ 
water stream or might clog the pipe. Generally, a rake type device is 
used to both loosen and screen the nodules, Deepsea Ventures has devel- 
