Recent Developments: Cargo liquefaction concerns

The often fatal outcome of shifting cargo was discussed again during 2015 with the IMO publishing a circular warning masters of the possible dangers of liquefaction associated with carriage of bauxite. The move was prompted by the loss of the 10-year-old Bahamas flag bulk carrier Bulk Jupiter, which was carrying 46,400 tons of bauxite when it sank rapidly with 18 fatalities in January 2015. It reminded masters to ensure the moisture limit is within specified boundaries, noting that while bauxite is classified as a Group C cargo (cargoes that do not liquefy or possess a chemical hazard) under the International Maritime Solid Bulk Cargoes (IMSBC) Code, there is a need to raise awareness of possible dangers of liquefaction associated with bauxite[ix]. Additionally, the MSC adopted a number of amendments to the IMSBC Code, all designed to improve requirements relating to cargoes that present a liquefaction risk.

As a result of liquefaction, carrying vessels may suddenly lose stability and take on a list or even capsize.

How does liquefaction happen?

All bulk ore and concentrate cargoes are likely to have some moisture content. However, if the moisture content of the cargo reaches a specific level known as the flow moisture point (FMP), the frictional force will be lost and the cargo will behave as if it were a liquid and flow freely. As a result of liquefaction, carrying vessels may suddenly lose stability and take on a list or even capsize[x].

A number of alerts have been issued highlighting the dangers, but AGCS believes more can be done to reduce the risk of liquefaction. “This is an area where we really need the support of technology to test the moisture content of these cargoes,” says Kinsey. Gerhard adds that a lot of responsibility rests with the master, but they may not have sufficient support from their employer due to commercial pressures: “Our concern is that the decision is made is at the weakest point of the chain, which is unfair. We have to force this conversation as it needs further discussion.”

Captain Rahul Khanna, Global Head of Marine Risk Consulting at AGCS, believes the industry has plenty of regulations to counter liquefaction, but implementation is where the real problem lies and, while cargo testing standards are prescribed, they are not always aligned. “The key issue is that the existing regulations need to be followed and we need a method to check that is happening,” he adds. “Many regions lack the infrastructure to carry out modern moisture content checks on cargo that can liquefy and some certificates are being issued which may not be completely reliable”.