Bauxite Could Liquefy – IMO Issues Warning

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In January 2015, Bulk carrier JUPITER along with its crew of 18 sank rapidly while on a voyage from Kuantan Malaysia to China. It was laden with 46,400 tons of bauxite.  This incident has once again alerted the maritime community and IMO has thus issued a caution notice to Ship Masters regarding the hazards linked with bauxite and particularly its potential for liquefaction.

The notice issued by IMOs office concerning Carriage of Containers and Cargos (CCC) states that the

Ship Masters may decline bauxite for carriage unless:

  • 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 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.

Cargo classification:

Group A cargo are those that are liable to liquefy, Group B cargo are known to possess chemical hazards, and Group C cargo are those that do not liquefy or possess a chemical hazard.

Bauxite is classed as a Group C in the International Maritime Solid Bulk Cargoes (IMSBC) Code. It is a brownish, yellow clay-like and earthy mineral, insoluble in water.

Liquefaction:

Stockpiles of bauxite are in open when they are waiting at ports of call. During the rainy season, the cargo gets wet, and the humidity prevents the cargo from draining or drying sufficiently before being loaded. There is a need to raise awareness of the possible dangers of liquefaction associated with bauxite.

Liquefaction occurs when a cargo that may appear dry on the surface, but has retained a certain level of moisture between particles. The rocking and rolling movement of the ship may cause the cargo to become viscous and fluid. This movement can then lead to destabilizing the balance in cargo weight and cause sudden capsize of the vessel. Therefore, special precautions should be taken when loading a cargo that has the potential to liquefy.

Section 2.1 of the IMSBC Code, states:

“Many fine-particled cargoes, if possessing sufficiently high moisture content, are liable to flow. Thus, any damp or wet cargo containing a proportion of fine particles should be tested for flow characteristics prior to loading”.

The IMO Sub-Committee highlighted the evidence uncovered since the loss of Bulk carrier Jupiter,as  possibly being due to liquefaction of cargo leading to loss of stability, listing and sinking.

Several organizations in Australia and Brazil are evaluating the properties of bauxite. While research in China indicates varied changes in the stability and weathering of bauxite based on its parent rock.

The Sub-Committee also established a correspondence group to evaluate the properties of bauxite and coal (some types of coal may liquefy) and consider any necessary amendments to the IMSBC Code.

Source: IMO

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