International Maritime Solid Bulk Cargo (IMSBC) Code categorizes cargoes into three groups, A, B & C:
A = cargoes which may liquefy if shipped at a moisture content in excess of their transportable moisture limit
B = cargoes which possess a chemical hazard which could give rise to a dangerous situation on a ship.
C = consists of cargoes which are neither liable to liquefy (Group A) nor to possess chemical hazards (Group B).
Liquefaction property of group A cargo is a major concern on safety of ship and its crew. In 2010 vessels Jian Fu Star, Nasco Diamond, Hong Wei and Vinalines Queen sank resulting in total loss of 67 lives at sea. The cargo carried by these four ill-fated vessels was nickel ore.
When liquefaction takes place vessel at sea may experience cargo shifting resulting in sudden loss of stability and capsizing.
When does liquefaction occur? Liquefaction takes place if the moisture content in cargo is above the Transportable Moisture Limit (TML). Since Nickel ore is not listed by name in IMSBC Code the carriage of nickel ore must be within the scope of section 1.3 “Cargoes not listed in this Code”
Recommendations are submitted to Maritime Safety Committee for implementing binding rules for engagement of National Competent Authority together with qualified laboratories for assessment of moisture content, TML to ensure cargoes which may liquefy is not loaded if moisture content is above TML.
Quote from China’s submission to Maritime Safety Committee (MSC89)
“China, as the country of nationality of the 45 seafarers [who lost their lives], carried out the investigation immediately after the accidents. In view of the fact that the subject ships had sunk and the difficulty to obtain cargo samples from the port of loading, the investigation was mainly based on the interviews with the surviving seafarers.
According to the evidence available, the direct cause of these accidents was the loss of stability as a result of cargo liquefaction and shifting in bad weather. However, the cargo documentation provided to the masters indicated that the moisture content of the cargo samples was lower than the Transportable Moisture Limit (TML)”.