Статья посвящена вопросам, связанным с особенностями перевозки бокситов навалом. Подкомитет по перевозке грузов и контейнеров Международной морской организации разработал новый циркуляр по перевозке бокситов (ССС.1), положения которого используются для подготовки планируемых изменений Международного морского кодекса по твердым навалочным грузам (IMSBC Code). Бокситовая промышленность ответила на призыв Международной морской организации исследовать поведение бокситов в процессе океанской перевозки созданием Глобальной рабочей группы по бокситам (GBWG), члены которой представляют все сегменты отрасли: отправителей (горнопромышленников), перевозчиков и потребителей (производителей глинозема), а также консультантов и морскую науку.
Research presented to IMO has found that certain forms of bauxite with a large proportion of smaller particles could be subject to the newly identified phenomenon of ‘dynamic separation’ when there is excess moisture in the cargo. The IMO has issued advice that bauxite may become unstable when carricd in bulk, potentially causing the vessel to capsize.
According to reports presented to the IMO, certain forms of bauxite with a large proportion of smaller particles could undergo dynamic separation when there is excess moisture in the cargo. During dynamic separation, a liquid slurry of water and fine solids can form above the solid material. The resulting free surface effect could significantly affect the vessel’s stability.
The draft new schedule for Group A bauxite states:
‘If free water or a liquid slum above the cargo or fluid state of the cargo is observed, including the flattening of the cargo, during voyage, the waster shall take appropriate actions to prevent cargo shifting, loss of stability due to free surface effect and potential capsize of the ship.
An atypical motion of the ship (wobbling) may also be indicative of cargo instability and the master shall consider appropriate action.’
According to a report from Gard P&I Club, ‘Like liquefaction, the process of dynamic separation can be prevented by ensuring that the bauxite has limited fines content and a limited moisture content, as both particle size distribution and moisture content are the main parameters for the occurrcnce of this phenomenon.’
Updated guidance
IMO’s Sub-Committee on Carriage of Cargoes and Containers has provided new guidance on the carriage of bauxite, in the form of a circular aimed at shippers, terminal operators, shipowners, ship operators, charterers and shipmasters. The circular requests that extreme care and appropriate action be taken, taking into account the provisions of relevant IMO instruments, when handling and carrying bauxite in bulk.
This takes immediate effect, ahead of the next scheduled adoption (in 2019) of the new test methods and relevant schedules for bauxite cargoes during the routine scheduled updating of the International Maritime Solid Bulk Cargoes (IMSBC) Code.
The CCC.1 circular updates a previous circular on carriage of bauxite and invites governments to note that bauxite cargoes with a larger proportion of smaller particles present a risk caused by moisture and should be treated as Group A cargoes. The Master should take appropriate action should the cargo show signs of possible instability.
The circular includes:
• Draft test procedure for determining the transportable moisture limit (TML) for bauxite;
• Draft individual schedule for bauxite of Group A (Bulk Cargo Shipping Name ‘BAUXITE FINES’);
• Draft amendments to the existing individual schedule for bauxite of Group С (bauxite with a lower proportion of smaller particles and with a degree of saturation by moisture not liable to reach 70%).
Global Bauxite Working Group (GBWG)
There is a long history of bauxites being shipped safely, and problems and accidents resulting from carrying bauxite cargoes are extremely rare. However, after the loss of the bauxite-carrying vessel Bulk Jupiter in early 2015, IMO asked the global bauxite industry to undertake research into the behaviour of bauxites during ocean transportation. The industry responded by forming the Global Bauxite Working Group (GBWG) to conduct research into the behaviour and characteristics of seaborne traded bauxites to inform IMO about safe shipping of these cargoes.
GBWG membership covers key disciplines including shippers (miners), transporters (ship owners/operators) and users (alumina refinery operators) as well as consultants with backgrounds in geoteclmical and hydraulic engineering, maritime science engineering and real world operations.
Further information on bauxite carriage and dynamic separation from a variety of sources is available in The Nautical Institute’s Knowledge Library.
Источник: Seaways. – 2018. – March. – P. 16.