A new warning that bauxite may become
unstable when carried in bulk on a ship, potentially causing the vessel to
capsize, has been issued by the International Maritime Organization (IMO).
Bauxite is one of the world’s major
sources of aluminium with around 100 million tonnes transported annually by
sea. In 2015, a bulk carrier sank while transporting bauxite, with the loss of
18 seafarers. Research presented this week to an IMO Sub-Committee found that
certain forms of bauxite with a large proportion of smaller particles could be
subject to a newly-identified phenomenon of “dynamic separation” when there is
excess moisture in the cargo, adds an IMO release.
In such conditions, liquid slurry (water
and fine solids) can form above the solid material, according to the report of
an international Global Bauxite Working Group on Research into the Behaviour of
Bauxite during Shipping. The resulting free surface effect of liquid sloshing
about could significantly affect the vessel's stability, leading to the risk of
the ship capsizing.
IMO’s Sub-Committee on Carriage of
Cargoes and Containers (CCC 4, which met 11-15 September at IMO Headquarters),
raised awareness on the potential risks posed by moisture and provided new
guidance on carriage of bauxite, in the form of a circular aimed at shippers,
terminal operators, shipowners, ship operators, charterers, shipmasters and all
other entities concerned.
The circular requests that extreme care
and appropriate action be taken, taking into account the provisions of relevant
IMO instruments, when handling and carrying bauxite in bulk.
The circular takes immediate effect, ahead of the next scheduled adoption (in 2019)
of the new test methods and relevant schedules for bauxite cargoes during the
routine scheduled updating of the International Maritime Solid Bulk Cargoes
(IMSBC) Code. The IMSBC Code is the industry rulebook on how to deal with bulk
The CCC.1 circular updates a previous
circular on carriage of bauxite and invites Governments to note that some
bauxite cargoes (specifically those with a larger proportion of smaller
particles) present a risk caused by moisture and should be treated as Group A
cargoes. Excess moisture in such cargoes can lead to a free surface slurry.
This can cause atypical motion of the ship (wobbling). The master should take
appropriate action in the event of this possible sign of cargo instability.
The circular includes the draft Test Procedure for Determining the
transportable moisture limit (TML) for bauxite; the draft individual schedule
for bauxite of Group A (Bulk Cargo Shipping Name "BAUXITE FINES");
and draft amendments to the existing individual schedule for bauxite of Group C
(bauxite with a lower proportion of smaller particles and with a degree of
saturation by moisture not liable to reach 70%).
Bauxite is a rock formed from the weathering of either silicate rocks
(granite/basalt) or carbonate rocks (limestone/dolomite). Bauxite is found
mainly in tropical and sub-tropical areas such as Africa, South America and
Australia with some small deposits located in Europe.
A total of approximately 100 million
tonnes (Mt) of bauxite is transported by sea annually. Brazil and Guinea
dominate seaborne supply with over 30Mtpa each. Australia supplies over 20Mtpa
and Malaysia accounts for about 10Mtpa. Small amounts are supplied from Sierra
Leone, Guyana, Ghana and other shippers.
Bauxite Working Group (GBWG)
There is a long history of safely shipping bauxites over many decades and
problems and accidents resulting from carrying bauxite cargoes are extremely
rare. However, after the loss of the bauxite carrying vessel the Bulk Jupiter
in early 2015, the global bauxite industry was requested by IMO to undertake
research into the behaviour of bauxites during ocean transportation. The global
bauxite industry responded by forming the Global Bauxite Working Group (GBWG)
to conduct research on the behaviour and characteristics of seaborne traded
bauxites to inform the IMO in relation to the safe shipping of bauxites.
The GBWG membership consists of a wide
variety of key disciplines, including shippers (miners), transporters (ship
owner/operators) and users (alumina refinery operators) as well as various
consultants with backgrounds in geotechnical and hydraulic engineering,
maritime science engineering and real world operations.
For a copy of the GBWG Report on
Research into the Behaviour of Bauxite during Shipping please