IMSBC Code Group A – Nickel Ore – Iron Ore Fines – Bauxite
Cargo liquefaction may result in cargo shift and loss of stability; this has been the cause of a number of serious casualties during the last years and now liquefaction is being considered as a major hazard for bulk carriers.
| Liquefaction occurs when a cargo (which may not appear visibly wet) has a level of moisture in between particles. During a voyage, the ship movement may cause the cargo to liquefy and become viscous and fluid, which can lead to cargo flowing with the roll of the ship and potentially causing a dangerous list and sudden capsize of the vessel. Special consideration and precautions should be taken when loading a cargo which may liquefy. |
DNV GL has recenlty published an informative guideline for the design and operation of vessels with bulk cargo that may liquefy. The main risk for a vessel carrying cargo that may liquefy is shifting of the cargo.
The following cargoes are subject to liquefaction:
1. IMSBC Code Group A
In the IMSBC Code, the cargoes have been divided into three groups. Group A consists of cargoes that may liquefy. Group B are cargoes with a chemical hazard. Group C cargoes are neither liable to liquefy nor to possess chemical hazards.
The majority of the Group A cargoes are various types of mineral concentrates. Fortunately there have not been many incidents related to these cargoes in recent years, most likely because the cargoes are uniform in nature, and the properties and condition are well controlled.
2. Nickel Ore
Nickel ore is arguably the most dangerous of all bulk cargoes, suspected of claiming the lives of 81 seafarers since 2010. The number of fatalities is horrific when taking into account that the nickel ore trade only amounts to approximately 2% of the total bulk cargo trade. The largest exporters of nickel ore have traditionally been Indonesia and the Philippines, but since the Indonesian ban on export of several types of unprocessed ores in January 2014, the Philippines has by far been the largest exporting country. The vast majority of nickel ore is shipped to China, where it is used for making stainless steel.
According to INTERCARGO’s Guide for the Safe Loading of Nickel Ore , thefollowing factors should be taken into consideration: Shipper’s Declaration,Correct BCSN,TML,Moisture Content (MC), Actual moisture content must be below the Transportable Moisture Limit,Visual inspection andVisual monitoring. Thecargo should be loaded in accordance with the provisions of SOLAS Chapter VI, the Code of Practice for the Safe Loading and Unloading of Bulk Carriers (the BLU Code), and the IMSBC Code including trimming requirements under Section 5.
The Nautical Institute has issued Mars Report regarding an accident occurred due to unsafe loading of nickel ore and unsafe anchorage which resulted in the loss of ship.
To avoid accidents due to nickel ore liquefaction please read the following:
Safe Carriage of nickel ore
Safe loading in cargo in bulk of nickel ore
3. Iron Ore Fines and Iron Concentrate (Sinter Feed)
Iron ore fines are iron ore with a large proportion of small particles (10% smaller than 1mm, and 50% smaller than 10mm). The cargo may liquefy if the moisture content exceeds TML. Iron ore fines have been associated with several accidents in recent years.
A contributing factor to the accidents is believed to be that the cargo has been wrongly categorized as normal iron ore, which, according to the IMSBC Code, is cargo that poses no liquefaction risk. In a response to this, Australia and Brazil fronted an initiative to the IMO to amend the IMSBC Code with an individual schedule for iron ore fines, and also with a modified TML test procedure.
The mandatory entry into force of the amended IMSBC Code is January 1st 2017, but it is strongly recommended to implement the amendments as soon as possible
Read SAFETY4SEA article on the early implementation of draft amendments to the IMSBC Code here.
4. Bauxite
Bauxite is an aluminium ore, and the worlds main source of aluminium. The bauxite is mined in openpit mines, then converted to alumina (aluminium oxide), which is in turn further processed to pure aluminium by electrolysi
Shipowners, operators and charterers should exercise extreme care when dealing with any cargo that has the potential to liquefy, and Intercargo reiterates the importance of caution being the best policy. If there is any doubt whatsoever as to the authenticity or content of the cargo declaration, Intercargo strongly advocates the use of independent tests to check and report the actual cargo condition prior to loading.
After tragic loss of the Bulk Jupiter earlier this year following the liquefaction of her bauxite cargo, steps have been taken to increase awareness of the nature of bauxite and prevent such incidents happening again. IMO has issued circular CCC.1/Circ.2 to advise masters when to accept cargo of bauxite. The circular warns ship Masters not to accept bauxite for carriage unless:
- the moisture limit for the specific cargo is certified as less than the indicative moisture limit of 10% and the particle size distribution as is detailed in the individual schedule for bauxite in the IMSBC Code; or
- the cargo is declared as Group A (cargoes that may liquefy) and the shipper declares the transportable moisture limit (TML) and moisture content; or
- the cargo has been assessed as not presenting Group A properties
Click here to learn about the most common causes for liquefaction-related incidents, along with DNV GLs guidelines for mitigating actions.
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The Transportable Moisture Limit (TML) of a cargo which may liquefy indicates the maximum moisture content of the cargo which is considered safe for carriage. The actual moisture content of the cargo at the time of loading will be measured and compared with TML. The TML is taken as 90% of the moisture content that is necessary for liquefaction to be possible, based on laboratory testing. This means that a safety margin is provided to protect against variations in cargo properties and moisture content, and against measuring errors in determination of TML or actual moisture content. The “can test”, which is commonly used by Masters for approximately determining the possibility of flow on board a ship or at the dockside, is an additional method. It should be noted that the can test is a supplement for laboratory testing rather than a substitute. |
Lloyd’s Register, the UK P&I Club, and Intercargo have produced a pocket guide for ships’ officers and agents who arrange cargoes for loading including the following fowchart for the safe loading:
