The IMO has issued a new warning on the bulk carriage of bauxite.
In 2015, the bulk carrier Bulk Jupiter sank while transporting 46,400 tons of bauxite about 150 nautical miles off the coast of Vung Tau, Vietnam, with 18 fatalities and only one survivor.
The marine safety investigation into the loss uncovered evidence to suggest liquefaction of cargo led to a loss of stability. Liquefaction occurs when a cargo (which may not appear visibly wet) has a level of moisture in between particles. Ship movement may cause the cargo to become fluid, and this can lead to cargo flowing with the roll of the ship and potentially causing a dangerous list and sudden capsize.
At the time, IMO’s Sub-Committee on Carriage of Containers and Cargoes established a correspondence group to evaluate the properties of bauxite and coal and consider any necessary amendments to the IMSBC Code. Research presented last week 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.
In such conditions, a liquid slurry (water and fine solids) can form above the solid material. 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 September 11-15 at IMO Headquarters) issued a new circular aimed at shippers, terminal operators, shipowners, ship operators, charterers and shipmasters.
The circular takes immediate effect, ahead of the next scheduled adoption (in 2019) of the new test methods and updating of the International Maritime Solid Bulk Cargoes (IMSBC) Code.
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.
Bauxite is one of the world’s major sources of aluminum with around 100 million tons transported annually by sea. 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.