Moisture content limit of iron ore fines for the prevention on liquefication in bulk carriers

In 2013, over 500 million tonnes of Iron Ore Fines (IOF) were transported around the world using bulk carriers, more than any other unrefined mineral. Since the holds of bulk carriers have not been designed to carry liquid, if liquefaction of IOF or other minerals occur it can cause the vessel carrying the cargo to list or even capsize. Since 2006, there have been at least eight reported bulk carrier incidents possibly caused by the iron ore cargo shifting. Currently, the only available parameter used to prevent this from occurring is the Transportable Moisture Limit (TML). The TML is the maximum gross water content that certain mineral cargoes may contain, while being loaded in bulk carriers, without being at risk of liquefying during transportation. The objective of this study is to compare the three test methods stated in the 2013 International Maritime Solid Bulk Cargoes Code (IMSBC Code), which are used to determine the TML of IOF. They are the Proctor/Fagerberg, Flow Table and Penetration test methods. The study also covers recent developments and advancements made in the field, which includes the Modified Proctor/Fagerberg test along with goethite content provisions, which are included in the 2013 draft individual schedule for IOF, and to be amended in the 2015 IMSBC Code. This study shows that the three test methods, stated in the 2013 IMSBC Code, which are used to determine the TML of minerals, are not appropriate for testing of IOF and that recent developments, such as the Modified Proctor/Fagerberg test along with goethite content provisions, permits IOF to be transported at higher moisture contents than if one of the previous three test methods were used.