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The Last Resource
the necessary lift by feeding in compressed air about half—way up the
tube which collects the gravel. The air froths up the contents of the
tube making them less dense and causing them to rise to the surface
and, providing the upper end of the tube is not too high above the
surface, to ow out. The loss is made good by water and material
rushing in at the bottom. Surprisingly enough, this system gives
quite a substantial ow rate. Then, there is the wire—line dredge
which consists essentially of a grab or dredge on the end of a stout
wire line. It can be manipulated at any depth and, together with
corers, is an essential part of the equipment used to collect samples
of really deep sediments. On the other hand, the rate at which
material can be gathered is obviously fairly limited since—unlike
ladder, suction and air lift dredges—the process is not continuous.
Finally, we move to those unborn monsters of the deep which will
wrest the mineral deposits from the deepest oceans. Dr Mero has
proposed that the equivalent of giant vacuum cleaners should work
over the bottom. These deep—sea hydraulic dredges would remove a
thin layer of material from the sea oor while disturbing the oor
itself as little as possible. They would be operated remotely from the
surface and, to help in this, their path would be scanned by under—
water television cameras. According to Dr Mero, this type of dredge
could recover as much as 10,000 tons of nodules a day and would be
able to operate in about 13,000 feet of water—the average depth of
the nodules in the Pacic. For shallow depths less than 4,000 feet, a
_
deep sea wire—line dredge, based on the type used by oceano—
graphers, might be economic.
There is no shortage of ideas in this ‘fringe area’ of marine
exploration. According to one suggestion an automated dredge
could be kept permanently on the deep ocean oor where it would
rendezvous from time to time with remote—controlled carriers. The
carrier, equipped with ballast tanks or some similar buoyancy
device, would hover above the dredge pumping aboard the accumu—
lated material. With the completion of the transfer the tanks would
be ‘blown’ and the carrier would head towards the surface where it
would be met by the larger ‘parent’ vessel. This might be a large
factory ship capable of some preliminary processing. It would lower
a suction pump and take out the contents of the recently returned
carrier without the latter having to surface properly. The empty
carrier would then have its tanks ooded in order to go down for
the next load.
The Last Resource
the necessary lift by feeding in compressed air about half—way up the
tube which collects the gravel. The air froths up the contents of the
tube making them less dense and causing them to rise to the surface
and, providing the upper end of the tube is not too high above the
surface, to ow out. The loss is made good by water and material
rushing in at the bottom. Surprisingly enough, this system gives
quite a substantial ow rate. Then, there is the wire—line dredge
which consists essentially of a grab or dredge on the end of a stout
wire line. It can be manipulated at any depth and, together with
corers, is an essential part of the equipment used to collect samples
of really deep sediments. On the other hand, the rate at which
material can be gathered is obviously fairly limited since—unlike
ladder, suction and air lift dredges—the process is not continuous.
Finally, we move to those unborn monsters of the deep which will
wrest the mineral deposits from the deepest oceans. Dr Mero has
proposed that the equivalent of giant vacuum cleaners should work
over the bottom. These deep—sea hydraulic dredges would remove a
thin layer of material from the sea oor while disturbing the oor
itself as little as possible. They would be operated remotely from the
surface and, to help in this, their path would be scanned by under—
water television cameras. According to Dr Mero, this type of dredge
could recover as much as 10,000 tons of nodules a day and would be
able to operate in about 13,000 feet of water—the average depth of
the nodules in the Pacic. For shallow depths less than 4,000 feet, a
_
deep sea wire—line dredge, based on the type used by oceano—
graphers, might be economic.
There is no shortage of ideas in this ‘fringe area’ of marine
exploration. According to one suggestion an automated dredge
could be kept permanently on the deep ocean oor where it would
rendezvous from time to time with remote—controlled carriers. The
carrier, equipped with ballast tanks or some similar buoyancy
device, would hover above the dredge pumping aboard the accumu—
lated material. With the completion of the transfer the tanks would
be ‘blown’ and the carrier would head towards the surface where it
would be met by the larger ‘parent’ vessel. This might be a large
factory ship capable of some preliminary processing. It would lower
a suction pump and take out the contents of the recently returned
carrier without the latter having to surface properly. The empty
carrier would then have its tanks ooded in order to go down for
the next load.