The West P&I Club informed that it has recently experienced a cargo liquefaction case, involving a full cargo of Ball Clay loaded in Lumut, Malaysia for discharge in Chittagong, Bangladesh, similar to another case experienced in 2013. In view of this, the Club urges operators to pay attention when loading a clay cargo.
According to the cub, laboratory testing of samples of the cargo drawn from the vessel showed a Flow Moisture Point (FMP) of 29.7% and Transportable Moisture Limit (TML) of 26.7%, when determined on the flow table, and an FMP of 32.1% and TML of 28.9% when determined by the penetration test. The lowest moisture content of the cargo onboard was notably higher than either TML, at 36.4%.
The International Maritime Solid Bulk Cargoes (IMSBC) Code contains a schedule for Clay, describing it as a light to dark grey product which is usually moist but not wet to the touch comprising of 10% soft lumps and 90% soft grains. The entry states that the cargo shall be kept as dry as practicable, that it shall not be handled during precipitation and that the moisture content of the cargo shall be kept as low as practicable to prevent the material from becoming glutinous and difficult to handle.
Although the schedule for Clay classifies it as Group C (ie a material which has no chemical hazards and is not liable to liquefy), this is a generic entry which does not necessarily apply to all clays. For example, the IMSBC Code contains a schedule for Ilmenite Clay which is classified as Group A (ie a material which may liquefy). In November 2000 a vessel carrying Ilmenite Clay was almost lost off the coast of Finland following the liquefaction of such a cargo.
It should also be noted that the Code of Safe Practice for Solid Bulk Cargoes (the predecessor to the IMSBC Code) once contained an entry for Kaolinite Clay which referred to this cargo as having a Transportable Moisture Limit (TML), thus indicating that it could liquefy. The latter observation is particularly important given that Ball Clay is a type of Kaolinite Clay.
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