standardization of environmental data and information - International ...

ecolonisation rates. If the area was recolonised in a week, recovery from a
large-scale disturbance might be relatively fast. If it took ten years, recovery
might be relatively slow. One thing that had been learned in regard to
standardization and the design of monitoring and impact studies was that
different components of the ecosystem would not respond in the same way
and might need to be monitored with different techniques and time scales.
Tailings discharge
A question was raised about whether mining tailings were likely to
be discharged at the surface or in mid-water. Smith replied that, as he
understood current thinking, surface discharge should be minimized though
some was inevitable. One approach, for purposes of discussion, might be
that, since a big plume was being created by mining in the benthic boundary
layer, the discharge should take place in the part of the environment
already sullied.
Mr. Lenoble observed that for the time being there was no
regulation about this problem because most regulations dealt only with
exploration. Companies active in this sphere were thinking of ways to
reduce surface discharge but there had been little or no testing; they would
have time to do that during the 15-year exploration phase. The discharge at
the surface would come not only from the sediment but also from the fine
particles of manganese hydroxide produced during the transportation and
manipulation of the nodules. There would in fact be another discharge, at
the bottom during nodule collection, when some separation would take
place between nodules and sediment to avoid raising most of the sediment
to the surface, thereby reducing surface discharge. The problem at the
bottom would be to try to discharge the sediment in such a way as to avoid
making a big plume above the seabed and to avoid dispersion of the
sediment by having the plume flatten quickly to the bottom.
Another participant commented that the discharge level was more
of an environmental than an engineering issue, since a system could be
designed either way. It was premature to specify the level, given the lack of
environmental knowledge.
Smith agreed that a recommendation as to the location of the
discharge would be premature. However, perhaps the Workshop might
propose some scenarios for discharge experiments. Otherwise, if there
were only one or two cases of test mining, with no recommendations about
discharge depth and monitoring, there would be no opportunity to study
INTERNATIONAL SEABED AUTHORITY 80