Dangers of Cargo Liquefaction Examined
Posted by Michelle Howard
Thursday, July 28, 2016
Over the past decade, at least 100 seafarers have lost their lives due to incidents which have been attributed to bulk cargoes liquefying at sea. UK P&I Club Senior Claims Director Alan Speed looks at the dangers of cargo liquefaction and the steps members can take to mitigate the risk.
“The issue of liquefaction remains high on the UK Club’s Loss Prevention agenda. Solid bulk cargoes such as unprocessed mineral ores and refined mineral concentrates have certain characteristics that, although they may appear to be in a dry, granular state upon loading, contain enough moisture to become fluid under the compaction and vibration that occurs during a voyage. The resulting cargo shift can be sufficient to capsize a vessel and sadly cost lives.
“More tragic is these deaths could have been prevented if a simple test had been carried out and acted upon before the ships left port. The so-called ‘can test’ is exactly what it says: put some cargo in a can, bang it on the ground for a minute and see if the contents start to flow. If they do, stop the loading and get some proper laboratory tests done – regardless of what it says on the cargo documentation.
“UK P&I Club has produced seven videos in partnership with global cargo experts Minton Treharne & Davis (MTD), to explain what a ‘can-test’ is and what it looks like in practice.
“However, members should be aware that a negative ‘can-test’ result does not necessarily mean the cargo is safe for shipment. If samples remain dry following a can-test, the moisture content of the material may still exceed the Transportable Moisture Limit’. As such, it is recommended that if the can-test fails or there is a suspected failure members should:
- Stop loading;
- Issue a Letter of Protest; and
- Seek further advice from P&I Club. They may require surveyor / reputable cargo expert involvement and further lab testing.
UK P&I Club provides advice on particular points that should be paid attention to:
- Nickel, Bauxite and Iron Ore are most susceptible to liquefaction. The IMSBC code specifies standards for transporting each of these ores to prevent risk of liquefaction
- Prevention of liquefaction is achieved through sampling and testing of the ore for their TML (Transportable Moisture Level) and MC (Moisture Content) no more than 6 months before transportation
- The TML (Transportable Moisture Level) test of any cargo to be loaded should be conducted within 6 months of the date of loading for homogenous material where no change in physical characteristics would be expected
- MC (Moisture Content) testing and sampling should not be carried out more than 7 days prior to the date of loading. These timings are the mandatory intervals between sampling and loading and must be strictly adhered to. If it has rained during these periods, further re-sampling / testing is required
- Testing and constant vigilance of any doubtful cargo is the only way to ensure a minimised risk of liquefaction