The Liberia Maritime Authority has released a Marine Advisory notice to provide guidance for the safe transportation of bauxite. It also gives the potential risks regarding the carriage of certain Group A bauxite in bulk due to its potential to undergo dynamic separation.
After the investigation into the loss of the M.V. BULK JUPITER in 2015 with a cargo of bauxite, IMO published CCC.1/Circ.2 on Carriage of Bauxite that may liquefy. At the time, bauxite was listed in the IMSBC Code as a Group C cargo (cargoes neither liable to liquefy- Group A or possess chemical hazards Group B).
For a more peer reviewed report on the nature of bauxite cargoes and to develop a globally applicable transportable moisture limit (TML) test for bauxite cargoes, the Global Bauxite Working Group (GBWG) was established in 2016.
GBWG indicated that Bauxite Fines containing more than 30% of fine particles less than 1 mm and more than 40% of particles less than 2.5 mm (Group A) may be unstable because of moisture content, resulting in dynamic separation and formation of a liquid slurry (water and fine solids) above the solid material, and a free surface effect which may affect the ship’s stability. This cargo is not liable to undergo dynamic separation when the cargo is shipped below its TML.
In September 2017, after further discussion was held at the IMO and having noted that some Bauxite cargoes should be classified as Group A, the following were finalised:
– The draft Test Procedure for Determining the TML for Bauxite.
– The draft individual schedule for Bauxite of Group A having the Bulk Cargo Shipping Name “BAUXITE FINES”.
– The draft amendments to the individual schedule for Bauxite of Group C.
Pending adoption of the draft amendments referred to in the paragraph above in 2019 and expected entry into force of the draft amendments to the IMBSC Code on 1 January 2021, operators should be very careful and take the appropriate action, considering the provisions of relevant IMO instruments when handling and carrying Bauxite in bulk and the conditions in the attached IMO circular, CCC.1/Circ.2/Rev.1.
Operators should also consult section 7 of the IMSBC Code, for additional information on cargoes that may liquefy and may carry out a check test to determine the possibility of flow by the auxiliary method prescribed in section 8 of the IMSBC Code.
AMSA has offered an explanation of dynamic separation phenomena in bauxite cargoes, which can be seen in the short video below. It also demonstrates the effects of the free slurry surface a vessel’s stability.
Read the Marine Advisory notice: LISCR-Carriage-of-Bauxite-and-other-solid-bulk-cargoes-that-may-liquefy