Bauxite Loadings

Bauxite Loadings - S America/Asia

Maritime cargoes of bauxite are generally carried safely and, provided proper procedures are followed, that should remain the case. However, the tragic loss in January 2015 of Bulk Jupiter, which had loaded bauxite at Kuantan in Malaysia after a period of heavy rain, serves as a stark reminder to shipowners and charterers of the potential dangers from liquefaction of these cargoes.

The purpose of this bulletin is to provide some general background information on bauxite but, more importantly, to reiterate practical steps that can be taken when loading this and other potentially liquefiable cargoes as well as tell-tale warning signs that should be looked for.

Numerous bulletins have been issued in recent years focusing on the potential liquefaction risk posed by bauxite cargoes originating from the South America and Asia. One of the key issues is the current bauxite schedule in the International Maritime Solid Bulk Cargoes (IMSBC) Code which, as a consequence of the very broad particle size range described under ‘characteristics’, can result in a liquefiable ‘Group A’ cargo being incorrectly classified as non-liquefiable ‘Group C’.


Bauxite, like iron ore fines and nickel laterite, is a mineral ore which is simply extracted from the ground and shipped with little or no processing. As a consequence the material contains a broad range of particle sizes ranging from very fine powder all the way up to quite large rocks, although the proportion of fine material and coarse lumps varies depending on the source.

However, when bauxite is processed the large lumps of ore require crushing to enable efficient extraction of the alumina – the material which is subsequently converted into aluminium. The crushing operation involves additional time and expense and as a consequence, some Chinese end-users have over the last few years changed their bauxite cargo specifications such that no lumps larger than 100 mm are to be included in the shipment. This resulted in some Indonesian mines sieving the ore to remove the >100 mm fraction, an operation which can involve washing the ore through a rotary sieve to produce both bauxite fines and coarser material. It is as yet unclear whether sieving is also being conducted at Malaysian bauxite mines.

It is estimated that Chinese processors will require about 130 million tonnes of bauxite this year of which about 37 million tonnes is imported. Previously much of this imported ore was supplied by Indonesia but, following the mineral export ban introduced in January last year, other sources have become more important. This include Malaysia, which is thought may supply up to about 10 million tonnes this year, up considerably from the 1.27 million tonnes shipped in the first 9 months of 2014.

Sieving in operation at a bauxite mine in Kalimantan, Indonesia - this effectively increases the fines contents as well as increasing the water contents, making the cargo more likely to liquefy.

Close-up of slurry of bauxite fines underneath the rotary sieve - the water content can be substantially increased during the sieving process, potentially making it a Group A cargo.

One of the problems with sieving is that high pressure water cannons are used to force the ore from the loading hopper into the rotary sieve (see photographs above). This increases substantially the moisture content of the fines fraction to the extent that even slurries can form (as shown above) with the risk that the ore will not subsequently lose that moisture by natural drainage or drying (see photographs below). Some Indonesian mines stockpile the fines separately and may ship these out as discrete parcels or mix them in with the slightly coarser ore. This is sometimes done because the fines usually have higher alumina content and are used to ensure that the alumina content of the ore, as specified in the sales contract, is maintained.

It should also be noted that the fines have higher moisture content, typically around 15% or more. This is to be expected as the water is trapped/retained between the particles of fines, as indeed is the case for all IMSBC Code Group A liquefiable cargoes. If the ore is saturated (i.e. contains water at levels in excess of that which can be held within the structure of the material), then some natural drainage is likely to occur. If such a cargo has been loaded, then drainage and accumulation of water may result in pooling of water around the periphery of the stow, or in the lower reaches of the cargo stows where, due to the presence of fines, the water may not be able to drain freely into the bilges.

In reality the schedule is misleading, with the potential of being dangerously so.

What can be done to ensure safety?

Since it is not known what the relative proportion of particle size is required to change bauxite Group C into bauxite Group A, we would caution that potentially many bauxite shipments, and especially those now being produced via a sieving process to remove the >100 mm fraction, are potentially Group A. We strongly recommend therefore that owners and charterers should assume that any wet or moist cargo of bauxite containing an appreciable amount of fines is Group A unless testing has shown otherwise – even if the bauxite mine has issued a cargo declaration stating the material to be Group C.

On board the vessel, the master, officers and crew should, as with any potential or declared Group A cargo, conduct frequent and regular can-testing in accordance with the method set-out in Section 8 of the IMSBC Code. Development of a flat surface with signs of free moisture (i.e. glistening or shiny surface) are indicative of a flow state and thus a ‘fail’ (see photographs below).

Two bauxite samples before can testing (left) and after testing (right) - both are ‘fails’ and should be tested for flow characteristics before loading continues.

The crew should also keep a close watch for the presence of cargo splatter marks on the bulkheads, shell plating and hatch coamings as these can only arise as a result of transient liquefaction of the cargo as it is being dropped onto the developing cargo stow in the holds. The presence of such marks indicates that portions of the cargo loaded have moisture content in excess of FMP. In addition, the crew should check for accumulation or pooling of water around the periphery of the stow as this may indicate that the cargo is saturated.

Bauxite splatter marks are the result of transient liquefaction - the cargo should be tested for flow characteristics before loading continues.

Bauxite splatter marks are the result of transient liquefaction - the cargo should be tested for flow characteristics before loading continues.

In the event of failed can tests, or the presence of splatter marks and/or pools of free water, our advice to shipowners and charterers is to suspend loading until the cargo has been properly tested for flow characteristics in a laboratory.

Source of information

Loss Prevention Department

Thomas Miller P&I (Europe) Ltd


N Crouch

Brookes Bell


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