What is the cargo?
As the name of the product indicates the cargo is made up principally of magnetite but also of Vanadium and Titanium, these last two elements at lower quantities (10-14%) as a solid solution. Knowing the elements is important because they are rare products and are considered important to steel making and other industrial processes. Cargo experts Roxburgh state that the material composition can vary greatly depending on the original formation process, which determines how the material is processed by the mine and in turn the final particle size distribution (PSD) and grade of the cargo. The cargo can be presented for loading as a lump or fines product with minimal processing, or as a much finer concentrate where gravity or magnetic processes have been applied to upgrade the valuable minerals.
Are there any risks?
The lump/coarse cargo is similar in behaviour to iron ore and typically has a low moisture content due to its large particle sizes, and as it is also usually free draining, this means any moisture in the cargo will drain away to the hold bilges. This cargo typically displays Group C IMSBC code classification characteristics and is unlikely to liquify on passage, although it is the responsibility of the shipper to assess and evidence these risks to ensure safe shipment.
The concentrate cargo grade can be very fine but is usually low in mineral clay impurities so it is also normally relatively free draining. However, the fine cargo may develop suction forces in the stow which will slow moisture draining from the cargo to the hold bilges. This may result in a wet base forming (an area of highly saturated material that develops at the base of the stow). If this happens, there is a risk of cargo shift on passage if not loaded and stowed correctly.
This cargo may well show Group A hazard characteristics and could encounter an issue such as shear failure / shift, at higher moisture contents under the stresses of the vessel’s motion at sea. It is again the responsibility of the shipper to assess these risks prior to loading commencing in accordance with IMSBC Code section 4, and if appropriate provide an accurate TML and moisture content certificate.
For a very fine, high magnetite content concentrate there is likely to be a risk of self-heating.
Both coarse and fine cargos with high magnetite content will be highly magnetic, therefore potentially affect the vessel’s magnetic compass readings.
Which IMSBC code schedule should I follow?
If the magnetite concentration is high, then the cargo may meet the criteria for Iron Ore or Magnetite concentrate depending how the mine processes the cargo and its particle size distribution. However, Vanadium Titanium Magnetite is not found in the IMSBC Code, and if not shown to be otherwise should be shipped under section 1.3 for cargoes not listed in the Code if the provisions for safe shipment are set and agreed by the competent authority at the port of loading. One of the issues with this is that it can be challenging to get reliable competent authority approval in Maputo.
What can be done?
Shipowners should be aware that any declaration received may not contain adequate detail and that any approvals for its carriage may not be from a party recognised as the competent authority.
Shipowners should consider approaching experienced technical experts for guidance on the carriage of this cargo to ensure it is safe for transportation.