液状化の危険性のあるボーキサイトの運送について

<要旨>ボーキサイト液状化の潜在的な危険性について指摘した、IMOによるCircular CCC.1/Circ.2 "Carriage of Bauxite which may Liquefy"が2015年に発行されていましたが、このたび国際ボーキサイトワーキンググループによる更なる研究を経て、一部のボーキサイト貨物はIMSBCコードのグループAに匹敵することが判明したため、IMOにより、IMSBCコードの改訂案を含む新たなCircularが発行されました。詳細はCircular CCC.1/Circ.2 /Rev.1 をご覧ください。

IMO warn of new hazards associated with the carriage of bauxite cargo

Following the loss of the Supramax bulk carrier BULK JUPITER in January 2015 with the loss of 18 lives, the IMO Sub-Committee on the Carriage of Cargoes and Containers (CCC), at its second session in September 2015 noted that the loss of the ship may have been caused by liquefaction of the cargo. Circular CCC.1/Circ.2 "Carriage of Bauxite which may Liquefy" was issued at that time to raise awareness to the potential risks posed by moisture in the carriage of Bauxite. Although Bauxite is described in the IMSBC Code as a Group C cargo, the potential for this cargo to liquefy was not specifically addressed in the Code.

Subsequent work undertaken by the industry Global Bauxite Working Group (GBWG) in conjunction with competent Authorities indicate that Bauxite presents a risk caused by moisture. As such some Bauxite cargoes should be treated as Group A cargoes. The advice provided by Circular CCC.1/Circ.2 has therefore been superseded by the outcome of the research undertaken and revised by Circular CCC.1/Circ.2 /Rev.1 dated 20 September 2017.

The revised circular includes information on draft amendments to the IMSBC Code as follows:

1. the draft Test Procedure for Determining the TML for Bauxite;
2. the draft individual schedule for Bauxite of Group A having the Bulk Cargo Shipping Name "BAUXITE FINES"; and
3. the draft amendments to the individual schedule for Bauxite of Group C

The draft amendments are also included in Annexes to the revised circular.

The Sub-Committee also noted that a Bauxite cargo of Group A is not listed in the IMSBC Code and shall be carried in accordance with subsection 1.3 of the Code

These amendments are expected to be adopted by the Maritime Safety Committee (MSC 101, in 2019) and the date of entry into force of these draft amendments to the IMBSC Code is expected to be 1 January 2021.

The Sub-Committee decided to invite Member States to take the aforementioned draft Test Procedure and draft individual schedules for Bauxite of Group A and Group C into consideration at the time of:

1. classification of Bauxite cargoes as Group A or Group C; and
2. setting the preliminary suitable conditions for the carriage of this cargo in accordance with subsection 1.3 of the Code, when the cargo is classified as Group A.

The following observation by the GBWG is also included:

"That an atypical motion of the ship (wobbling) may also be indicative of cargo instability. The master should take appropriate action."

The atypical motions (or wobble) is caused by the movement of a free surface slurry over the top of the cargo which is out of phase with the roll period of the ship. If left unchecked this movement of cargo has the potential to further reduce stability and the risk of capsize.

Member States are also invited to bring the information contained in the revised circular to the attention of shippers, terminal operators, shipowners, ship operators, charterers, shipmasters and all other entities concerned, requesting that extreme care and appropriate action be taken, taking into account the provisions of relevant IMO instruments when handling and carrying Bauxite in bulk.