The International Maritime Organization (IMO) has issued a safety circular on the carriage of the mineral bauxite, warning masters of the possible danger of liquefaction.
The advice has been issued by the Sub-Committee on Carriage of Containers and Cargoes after considering the findings of the Bulk Jupiter investigation. The 10-year old Bahamas-flagged bulk carrier was carrying 46,400 tonnes of bauxite when it rapidly sank off Vung Tau, Vietnam, in January this year. All but one of its 19 crew members were lost, declared dead or missing.
The safety investigation uncovered evidence suggesting liquefaction of cargo led to the ship’s loss of stability.
The circular informs ship masters of the conditions under which alone they should accept bauxite for carriage:
– the moisture limit for the specific cargo is certified as less than the indicative moisture limit of 10% and the particle-size distribution as is detailed in the individual schedule for bauxite in the International Maritime Solid Bulk Cargoes (IMSBC) Code; or
– the cargo is declared as Group A (cargoes that may liquefy) and the shipper declares the transportable moisture limit (TML) and moisture content; or
– the cargo has been assessed as not presenting Group A properties.
Under current regulations, the mineral is not classified as a Group A cargo. Under the IMSBC Code, bauxite is classified under Group C (cargoes that do not liquefy or possess a chemical hazard).
“There is a need to raise awareness of the possible dangers of liquefaction associated with bauxite,” said the IMO in a statement.
“If a Group A cargo is shipped with moisture content in excess of its transportable moisture limit, there is a risk of cargo shift, which may result in capsizing,” said the organisation.
Group A cargoes have to be tested before loading, to determine their TML and actual moisture content. Only if testing confirms that the cargo is below the maximum moisture content is that cargo considered safe for carriage.
The IMO revealed that the sub-committee has set up a correspondence group to evaluate the properties of bauxite and of coal given that some types of coal may liquefy. The group will also consider any necessary amendments to the IMSBC Code.
P&I clubs have issued several warnings this year about the dangers of liquefaction while carrying bauxite.
In January, the Norwegian P&I Club Skuld warned that liquefaction often occurs with bauxite when the cargo is pre-filtered to separate fine and large particles, the process of which may introduce water into the cargo, or when the cargo has undergone some other form of processing or crushing.