Liquefaction risks - Iron Ore Sinter Feed

8 July 2011

It is recommended that this alert is read in conjunction with the Circulars issued by the Association on 13 December 2010 (India - Safe shipment of Iron Ore Fines from Indian Ports, No 5:421) and 31 January 2011 (Indonesia and the Philippines - Safe Carriage of Nickel Ore Cargoes, No 5:428).

This concerns the shipping of a type of iron ore described as “sinter feed”.  The term sinter feed indicates that the cargo is too fine-grained for direct use in a blast furnace and therefore will undergo a process of agglomeration (“sintering”) into larger particles at destination before smelting.  Thus, it is descriptive of the use of the product rather than its properties or production method.  Some grades of sinter feed are known to be prone to liquefy.

The Association has received reports of Brazilian shippers declaring cargoes of sinter feed (or iron ore sinter feed) as Group C under the International Maritime Solid Bulk Cargoes Code (the IMSBC Code) but without any supporting documentation.  The ports involved include Ponta da Madeira, Tubarao, Itaguai and some ports in Santana.  Group C cargoes are not prone to liquefy and accordingly do not require the shipper to provide test results for Transportable Moisture Content (TML), Flow Moisture Point (FMP) and moisture content of the cargoes.

Several recent cargoes of Brazilian sinter feed have reportedly liquefied after loading as a result of the high moisture content of the cargo, despite shippers’ declarations at the loadport having described the cargoes as Group C.  Thankfully there have been no reported losses to date but the risk of a loss of stability and potential capsize is apparent.

Sinter feed is clearly listed in the IMSBC Code under IRON CONCENTRATE (sinter feed), which is covered by the entry on MINERAL CONCENTRATES.  Cargoes covered by this entry are Group A cargoes (cargo prone to liquefy).  It is consequently of paramount importance to ensure that any sinter feed cargo that can liquefy is treated as Group A cargo and that the shipper provides the vessel with reliable documentation setting out the TML, FMP and moisture content of the cargo so that the Master may satisfy himself that the cargo is safe to load.  Some of the confusion appears to arise from the shippers ignoring the IMSBC Code description of sinter feed as Group A cargo, reasoning that their sinter feed product is not produced by a concentration method and thus supposedly not covered by the MINERAL CONCENTRATES entry.  This is misconceived, as non-concentrated grades of sinter feed are the same as iron ore fines, whichthe IMO has ruled should be considered as Group A cargoes (see the Association’s circular of 13 December 2010 on Indian iron ore fines and IMO Circular No. DSC.1/Circ.63 of 12 October 2010).  In addition, the Code is very clear that all fine-grained cargoes with an inherent moisture content require flow testing before loading (Appendix 3, section 2.1, page 327, “Many fine-particled cargoes, if possessing a sufficiently high moisture content, are liable to flow.  Thus any damp or wet cargo containing a proportion of fine particles should be tested for flow characteristics prior to loading.”)

It is further reported that some shippers are advising Masters that ‘can tests’ are sufficient to determine the suitability of sinter feed for carriage.  The IMSBC Code encourages the use of such tests where there is doubt about the suitability of cargo presented during the loading operation.  The advice of experts consulted by the Association is that can tests are not a reliable means of verifying that a cargo is safe for shipment.  It is a secondary check that can help to identify cargo that presents a high risk of liquefying during the voyage. Shippers are required under the IMSBC Code to conduct testing of Group A cargoes under laboratory conditions prior to loading to establish its TML, FMP and moisture content so that its suitability for shipment can be established.  Masters should insist on receiving proper certification from the shippers showing the results of the laboratory testing of the cargo (and satisfy themselves that the moisture content is within the TML) prior to loading.

There are also reports of shippers failing to retest cargo following exposure to rain (as is required under the IMSBC Code), of a lack of reliable testing laboratories, of surveyors acting for both vessel and cargo interests and of sinter feed being misdescribed.

The Club consequently recommends that, unless analytical evidence is provided to the contrary, Members should consider all Brazilian sinter feed cargoes as Group A cargoes and observe all IMSBC Code requirements for the carriage of cargoes that are prone to liquefy.  If in any doubt as regards the veracity of the shipper’s certificates or the suitability of the cargo for carriage, Members are urged to consult the Club.

We would like to acknowledge the assistance of Brookes Bell in the preparation of this Alert.