Bauxite IMSBC Schedule: Group A and C Rules

Bauxite is carried under two separate IMSBC Code schedules: BAUXITE (Group C, not liable to liquefy) for the coarser lump grades, and BAUXITE FINES (Group A, liable to dynamic separation) for material with at least 30% of particles below 1 mm or at least 40% below 2.5 mm. That split was made mandatory from 1 January 2021, forced by the sinking of the bulk carrier Bulk Jupiter on 2 January 2015, which killed 18 of 19 crew off Vietnam and was attributed to dynamic separation of fine, moist bauxite. Dynamic separation is not classical liquefaction: the lower bulk stays solid while ship motion drives fine particles and free water upward to form a mobile slurry at the surface, which then shifts with each roll and overwhelms the vessel’s stability.

Seaborne bauxite trade ran roughly 165 million tonnes in 2024, making it one of the largest dry-bulk commodity flows by volume. The IMSBC Code governs the carriage of both grades. For the Group A regime that applies to bauxite fines, the Transportable Moisture Limit (TML), the certificate timing, and the master’s right to refuse are the same controls as for other Group A cargoes. The key difference is the test method: bauxite fines use a modified Proctor-Fagerberg procedure developed specifically for the cargo’s clay-mineral drainage behaviour.

To look up the current IMSBC schedule fields for either BAUXITE or BAUXITE FINES, including group, bulk density, and stowage factor, use the IMSBC bulk cargo finder. For a Group A moisture compliance check, the IMSBC TML moisture checker and the IMSBC liquefaction Group A calculator are the companion tools.

What bauxite is

Bauxite is the principal ore of aluminium, a heterogeneous rock formed by the intense tropical weathering of aluminium-bearing parent material. The weathering strips out silica and other components and concentrates aluminium as hydroxide and oxide minerals. Three mineral forms carry nearly all the aluminium content: gibbsite ($\text{Al(OH)}_3$), boehmite ($\gamma\text{-AlOOH}$), and diaspore ($\alpha\text{-AlOOH}$). Lateritic bauxites, the type found in Guinea, Australia, and tropical Asia, are dominated by gibbsite and are typically softer and more prone to fines generation. Karst bauxites, found in parts of China and the Mediterranean, carry more boehmite and diaspore and are harder.

Bauxite is not a single mineral but a rock defined by its aluminium content and its utility as a refinery feedstock. Ore grade is measured by available alumina (Al2O3), reactive silica (SiO2, which consumes caustic and increases processing cost), and total moisture. A typical traded laterite runs 40 to 55% Al2O3, below 10% reactive SiO2, and total moisture of 5 to 20%, depending on origin and season.

The bauxite-to-aluminium chain

Bauxite leaves the mine heading for a Bayer process alumina refinery, which dissolves the aluminium in hot caustic soda, separates it from the residue (red mud), precipitates aluminium hydroxide, and then calcines it to alumina at roughly 1,000 to 1,200 degrees Celsius. The USGS material balance: about 4 tonnes of dried bauxite yield 2 tonnes of alumina, which in turn yield 1 tonne of aluminium metal after electrolytic reduction. That halving at each stage is why alumina refineries tend to locate close to bauxite mines or at coastal refinery hubs, and why bauxite shipments are so much larger by volume than the alumina flows that follow.

World bauxite production was about 400 million tonnes in 2024 according to USGS Mineral Commodity Summaries 2026. Of that, roughly 165 million tonnes moved seaborne, with China as the overwhelmingly dominant importer at approximately 75% of the total. Alumina, the midstream product, is covered separately in the alumina IMSBC schedule.

Major export origins

Guinea has been the world’s largest bauxite exporter since 2017, shipping more than 105 million tonnes in 2024 through the ports of Kamsar, Conakry, Boké, and Boffa. Guinean laterite is high in gibbsite with moderate moisture and is generally loaded as coarse Group C material from large strip-mining operations in the Boké region. Australia ranks second, shipping from Weipa in Queensland (Rio Tinto) and from Gove in the Northern Territory. Australian bauxite is low-moisture and is the textbook Group C lump cargo, loaded by reclaimer and conveyor in long-established operations.

Brazil exports from Trombetas in the Amazon basin (Mineração Rio do Norte) and from Juruti (Alcoa), totalling roughly 30 million tonnes in recent years. Brazilian material varies: the coarser Trombetas product is Group C, but finer-fraction material from different processing stages can meet the BAUXITE FINES particle-size criteria and requires Group A treatment. Indonesia was a significant exporter to China before the 2014 government export ban restricted shipments, and its material had variable fines content. Malaysia is the case that matters most to the regulatory history: the bauxite that caused the Bulk Jupiter loss was loaded at Kuantan, Pahang, from laterite ore with a high kaolinite clay content and a significant fines fraction, carried under a Group C declaration that proved to be wrong.

The two IMSBC schedules: BAUXITE and BAUXITE FINES

The IMSBC Code now carries two individual schedules for bauxite in Appendix 1. They sit side by side in the listing, distinguished by particle size and group. Getting the right declaration is the shipper’s legal obligation and the starting point for safe carriage.

The particle-size criteria deserve care. A shipment in which the particle size distribution is not known must be tested before the shipper can declare it as Group C. The Code places that burden on the shipper, not the master. A shipper who declares a fines-criterion cargo as Group C to avoid the TML testing obligation is misdeclaring the cargo, which is a contravention of SOLAS Chapter VI and potentially a criminal matter under flag and port-state law.

BAUXITE: Group C schedule

BAUXITE in the Group C schedule is coarse lump material that does not meet the fines definition. The schedule records it as not liable to liquefy. Carriage under the Group C regime requires only the standard cargo declaration under IMSBC Code Section 4.2: the Bulk Cargo Shipping Name, the group, and the relevant physical properties. No TML certificate. No moisture content certificate. No restriction on loading in rain beyond general seamanlike practice.

The Group C designation does not remove all practical concerns. Coarse bauxite is a dense, abrasive cargo. It stows at 1,200 to 1,500 kg/m3, making it a deadweight-limited commodity on most bulk carriers. It discharges by grab and can be dusty, particularly at the load port if the stockpile has been disturbed by earth-moving equipment. Hold cleaning after bauxite is routine but thorough, since the ferrous residue from laterite ore can stain the next cargo if not removed.

Bilge systems should be clear and operational before loading. Some coarse bauxite cargoes release pore water during the voyage, particularly if loaded with higher natural moisture. That water, which can carry fine particles in suspension, must be pumped out periodically. Masters should note the bilge accumulation rate, since a steady increase in bilge water carrying a fine red-brown sediment in a hold declared as Group C bauxite is a sign that the cargo contains more fines than certified.

BAUXITE FINES: Group A schedule

BAUXITE FINES sits in the Group A section of the Code. The entry specifies the particle-size threshold that triggers the classification, the modified Proctor-Fagerberg test as the prescribed TML method, and the same documentation chain that applies to all Group A cargoes: TML certificate within six months and moisture content certificate within seven days before the commencement of loading. The cargo must not be loaded if the declared moisture content equals or exceeds the TML.

The schedule also carries the weather precaution common to Group A cargoes: loading must stop during precipitation. A Group A fine cargo exposed to rain in an open hatch can have its surface layer saturated within minutes. That wetted surface layer is already above TML and presents the conditions for dynamic separation to initiate at the top of the cargo mass.

Amendment 06-21 (IMO Resolution MSC.500(105), mandatory 1 December 2023) revised the Group A definition in the IMSBC Code to explicitly include dynamic separation alongside classical liquefaction. The amended text reads: “Group A consists of cargoes which may liquefy if shipped at a moisture content in excess of their transportable moisture limit (TML). This group also covers cargoes which may be subject to dynamic separation if shipped at a moisture content in excess of their TML.” Both BAUXITE FINES and certain fine coals are covered by that dynamic-separation limb.

The Bulk Jupiter casualty and the regulatory response

The sinking of the Bulk Jupiter is the event that changed how regulators, shippers, and operators treat bauxite. Getting the facts right matters because the casualty is sometimes described inaccurately in secondary sources.

The vessel and the cargo

The Bulk Jupiter was a 56,016 DWT Supramax bulk carrier built in 2009, flying the Bahamas flag. She was operated by Pacific Basin Shipping and managed by Anglo-Eastern Ship Management. In late December 2014 she loaded approximately 46,400 tonnes of bauxite at Kuantan port, Pahang, Malaysia, for delivery to China. The bauxite was of Malaysian lateritic origin, characterised by a significant kaolinite clay content and a fines fraction that, subsequent laboratory analysis showed, met the BAUXITE FINES particle-size criteria. At the time of loading, all bauxite was classified as Group C under the IMSBC Code. No TML testing was required. No moisture content certificate was needed. The shipper’s declaration identified the cargo as Group C bauxite.

Loading was completed around 29 December 2014. The region had experienced heavy rainfall in the period before and during loading. The master did not have the tools the IMSBC Code now requires for BAUXITE FINES, because those tools did not yet exist in the Code. The Group C classification in force was genuinely believed to apply.

The sinking

The Bulk Jupiter departed Kuantan and headed north through the South China Sea. On 2 January 2015, at approximately 10:10 hours local time, the vessel was approximately 250 nautical miles south-east of Vung Tau, Vietnam, in position 08° 28’ N, 109° 42’ E, in a loaded draught of about 11 metres. The crew reported a sudden heavy list to port. The list developed so rapidly that crew members were unable to reach lifeboats on the low side. The vessel capsized. Vietnamese coast guard and nearby vessels rescued one crew member. The other 18 members of the 19-person crew were killed.

The vessel sank in water approximately 70 to 80 metres deep. Divers subsequently inspected the wreck, which was located on its side. That inspection confirmed the vessel sank in the position reported, with no evidence of catastrophic structural failure before the capsize.

The Bahamas Maritime Authority investigation

The Bahamas Maritime Authority (BMA) published the final investigation report in 2021, six years after the casualty, following extensive analysis of the cargo behaviour and consultation with the Global Bauxite Working Group. The BMA investigation concluded that the probable cause was dynamic separation of the fine-fraction bauxite cargo.

The investigation found that the bauxite loaded at Kuantan contained a high proportion of fine particles meeting the BAUXITE FINES criteria, and that the natural moisture content of the cargo was high due to rainfall before and during loading. Ship motion at sea caused fine particles and free water to migrate upward through the cargo mass, forming a mobile slurry layer at the surface of the cargo in the holds. That surface slurry then shifted with each roll, producing a progressive and self-amplifying heeling moment that the vessel could not correct. The lower layers of bauxite, well compacted by the cargo weight above them, remained effectively solid throughout. The bilge wells were not accumulating water in a way that would have signalled classical liquefaction.

The BMA report also found that pre-loading sampling and documentation had not adequately characterised the cargo’s particle size or moisture content, that the state of the cargo at the time of loading was likely already above what would have been the TML had a Group A assessment been required, and that the current (2015) Group C classification of all bauxite did not reflect the actual behaviour of fine-fraction material.

The IMO regulatory response

IMO’s response to the Bulk Jupiter loss came in three steps.

First, at MSC 96 in May 2016, the IMO issued Circular MSC.1/Circ.1539, advising flag states and operators to apply caution with all bauxite cargoes and recommending that bauxite with a significant fines fraction be treated as potentially liable to dynamic separation pending the development of a formal test method and schedule.

Second, the Global Bauxite Working Group, convened under the Sub-Committee on Carriage of Cargoes and Containers (CCC), conducted research into bauxite liquefaction and dynamic separation behaviour. This body, comprising major bauxite shippers, mining companies, classification societies, and maritime research institutions, developed the modified Proctor-Fagerberg test specific to bauxite fines and the particle-size criteria for the new BAUXITE FINES schedule. Their technical work underpinned Amendment 05-19.

Third, Amendment 05-19, adopted in IMO Resolution MSC.462(101) and mandatory from 1 January 2021, formally split bauxite into the two schedules described above. BAUXITE FINES became a Group A schedule. The modified Proctor-Fagerberg test for bauxite became the prescribed TML method. The particle-size criteria became the classification trigger. From 1 January 2021, every shipment of bauxite required the shipper to determine whether the particle-size distribution placed the cargo in the Group C or Group A category, and to obtain the corresponding documentation.

Amendment 06-21, adopted in IMO Resolution MSC.500(105) and mandatory from 1 December 2023, refined the definition by explicitly incorporating dynamic separation into the Group A definition, closing the interpretive gap between liquefaction (uniform fluidisation) and the distinct mechanism the Bulk Jupiter investigation had identified.

Dynamic separation: the mechanism explained

Dynamic separation is not the same as classical liquefaction, though both are IMSBC Group A hazards and both can capsize a ship. Understanding the distinction helps practitioners recognise the conditions and warning signs for each.

Classical liquefaction

In classical liquefaction, the cargo undergoes a substantially uniform transition from solid to fluid behaviour through its depth, or at least through a significant layer. The driving mechanism is pore-water pressure build-up under cyclic loading. Ship motion applies repeated shear stress to the cargo. Each shear cycle compacts the grain structure, reducing void space. In a fine, low-permeability cargo, water cannot drain out faster than the voids close, so pore pressure rises. When pore pressure approaches the overburden stress, effective stress between grains falls to zero and the mass behaves as a fluid.

The detailed soil mechanics are set out in the cargo liquefaction article. The governing equation is:

where $\sigma'$ is effective stress, $\sigma$ is total (overburden) stress, and $u$ is pore-water pressure. Liquefaction occurs when $u \to \sigma$ and $\sigma' \to 0$. The cargo then flows as a dense fluid, with a free liquid surface that shifts with each roll.

In classical liquefaction the bilge wells typically fill with water containing fine particles, because drainage paths carry pore water downward through the cargo mass and into the well. A rising bilge level in a Group A hold is a classic warning sign.

Dynamic separation

Dynamic separation runs the opposite direction. Ship motion, primarily the repeated shear stress of rolling, drives fine particles and free water upward through the cargo mass rather than letting them drain downward. The mechanism relies on the particle-size segregation effect of vibration and shear: in a heterogeneous mass with a range of particle sizes, sustained cyclic motion causes the finer, lighter particles to migrate upward through the voids of the coarser matrix, a process analogous to what soil mechanicians call shaking segregation or Brazil-nut effect at the large-particle end.

The result is a stratified cargo: a lower layer of compacted, effectively solid coarse particles, and an upper layer that is a wet slurry of fine particles and free water. That upper slurry has a free surface and a low viscosity. As the ship rolls, the slurry shifts to the low side, adding a dynamic heeling moment on top of any static moment. The coarser lower layer remains solid and does not contribute to the heeling moment, but it cannot provide restoring righting arm either, because the metacentric height is being continuously eroded by the shifting free-surface effect of the slurry above.

The key practical difference from classical liquefaction: the bilge wells may stay dry. Because the water is migrating upward into the slurry layer rather than draining downward into the bilge system, the observable warning sign of rising bilge levels may not appear before the vessel’s stability is already critically compromised. The surface of the cargo in the hatch may look like a wet but still-solid mass rather than an obviously fluid pool. An officer checking bilge levels or looking through the hatch opening may see nothing alarming until the list begins to develop.

Why bauxite is prone to dynamic separation

Kaolinite is the key mineral. Lateritic bauxites, including the Malaysian material loaded on the Bulk Jupiter, carry a significant kaolinite clay fraction in the fine-particle portion of the size distribution. Kaolinite particles are platy (flat sheets rather than rounded grains), which reduces their drainage permeability and increases the tendency of the fine fraction to remain in suspension once mobilised. A kaolinite-rich fine fraction with elevated moisture content is the combination that the modified Proctor-Fagerberg test was designed to characterise, because its drainage response under compaction differs from the iron-ore fines and mineral concentrates for which the standard method was developed.

The coarser fraction of the same bauxite cargo, the particles that make up the lower layer during dynamic separation, is typically laterite pebbles with lower clay content. Those particles drain freely, which is why the lower layer stays solid. The separation of behaviour between the two size fractions is both the cause of the dynamic separation mechanism and the reason it was not anticipated under a Group C classification designed for the bulk-average behaviour of the cargo.

The TML framework for bauxite fines

The Group A controls for BAUXITE FINES follow the same structure as for all Group A cargoes, with one cargo-specific difference: the test method.

Moisture content and TML

Two quantities govern the carriage decision.

Moisture content (MC) is the mass of water in the cargo expressed as a percentage of the total wet mass:

where $m_w$ is the mass of water and $m_s$ is the mass of dry solids. It is determined by drying representative samples to constant mass at 105 degrees Celsius and measuring the mass loss.

Transportable Moisture Limit (TML) is the maximum MC at which the cargo may be carried on an ordinary bulk carrier. For the modified Proctor-Fagerberg test used for bauxite fines, the TML is derived from the compaction-saturation curve rather than from the $\text{TML} = 0.9 \times \text{FMP}$ formula used for the flow-table and penetration tests. The principle is the same: the TML is set at a safety margin below the physical flow threshold.

The carriage rule is binary:

There is no margin around equality. A cargo declared at exactly the TML is prohibited, not borderline.

The modified Proctor-Fagerberg test for bauxite

The Proctor-Fagerberg family of tests borrows from geotechnical soil compaction. A sample is compacted into a cylindrical mould in layers using a standard hammer, and the dry density and moisture content are recorded at each run. Multiple runs at different initial moisture levels trace a compaction curve peaking at the optimum moisture content (OMC). The degree of saturation at the OMC determines the TML.

The standard Proctor-Fagerberg method (PFC70) sets the TML at the moisture content that produces 70% saturation at the OMC. The iron-ore fines variant (PFD80) uses 80% saturation and a lighter hammer, because iron ore fines reach higher saturation at their OMC than a typical mineral concentrate. The bauxite modification, developed by the Global Bauxite Working Group, is tuned to bauxite’s specific drainage behaviour: the clay content, particularly kaolinite, slows drainage during compaction relative to a purely granular material, so the standard method does not adequately capture the pore-pressure build-up that occurs in bauxite fines under ship motion.

The modification for bauxite is mandatory for the BAUXITE FINES schedule. A TML certificate obtained by the standard PFC70 or PFD80 method is not a valid certificate for a BAUXITE FINES shipment. The certificate must state the test method used, and an accredited laboratory should be consulted to confirm which method applies. A TML certified by the wrong method represents a significant compliance gap, and P&I clubs have documented cases where different laboratories applying different methods produced TML values that differed by 2 to 3 percentage points on the same cargo.

Certificate timing and validity

Two certificates run on different clocks.

The TML certificate is valid for up to six months before the commencement of loading. TML is a physical property of the cargo type from a given source and processing route; it is stable over that period, barring a change in the source material or the processing parameters.

The moisture content (MC) certificate must be dated within seven days before the commencement of loading. MC is a condition, not a property. It changes with weather, rehandling, stockpile drainage, and the passage of time. If rainfall occurs after the MC sampling date, the certificate is void and the cargo must be retested. The seven-day rule is not a guideline; it is a Code requirement. A shipper who presents a 10-day-old MC certificate after intervening rain is presenting an invalid document.

Port state control examinations under the Paris and Tokyo MoU include checks on Group A cargo documentation. A missing or expired TML or MC certificate for BAUXITE FINES is a detainable deficiency. Masters who discover a documentation gap at the berth should not load, should document their refusal in writing, and should advise the shipowner and P&I correspondent.

The can test for bauxite fines

The can test, set out in Section 8 of the IMSBC Code, is a rapid shipboard screening check that a ship’s officer can perform during loading with no laboratory equipment. Take a representative sample from the loading stream and half-fill a cylindrical metal container of 0.5 to 1 litre. Bring the can down sharply onto a hard surface from about 0.2 metres and repeat 25 times at one- to two-second intervals. Examine the surface.

If free moisture appears, loading must stop and independent laboratory testing must be arranged before any decision to resume. That positive result is actionable.

A dry result does not clear the cargo. A bauxite fines sample at 95% of TML can pass the can test while the cargo remains at real risk. The IMSBC Code explicitly states the can test is a screening check only, not a substitute for laboratory certification. Masters should nonetheless perform it at the start of each loading shift and whenever the cargo stream changes in appearance, consistency, or colour, as a basic ship-side defence.

Loading precautions under the IMSBC Code

The Group A loading regime for BAUXITE FINES combines the standard Section 4 controls with cargo-specific requirements from the schedule.

Pre-loading checks

Hold bilge systems must be tested and confirmed fully operational before loading BAUXITE FINES. Bilge suction strainer covers must be in place and clear. The purpose is not to drain a liquefied cargo, which the bilge system cannot do, but to give the master early warning if moisture starts migrating through the cargo toward the well. In dynamic separation, that warning may arrive later or not at all, but non-functional bilges are always a deficiency.

Hatch covers must seal correctly. Any water infiltration through a defective hatch seal during the voyage can raise the surface moisture of the cargo above TML even if the cargo was loaded compliant. Hatch weathertightness checks before loading are required; an ultrasonic or chalk test of the compression seals is the documented standard.

Rain suspension

Loading of BAUXITE FINES must stop during precipitation. This is mandatory, not discretionary. Rain on fine bauxite in an open hatch saturates the surface layer within minutes. That layer can then act as a seeding layer for dynamic separation once the ship moves into a seaway, because it provides the initial pool of mobile fine-solids slurry that ship motion can extend.

The practical consequence for terminal operations is that rain gauges and wind-shift monitoring should be part of the loading protocol for BAUXITE FINES. A squall that passes in 20 minutes but delivers 10 mm of rain on an open hatch may require a fresh can test and, in marginal conditions, a fresh MC sample before loading resumes.

Trimming

The Code requires that BAUXITE FINES be trimmed so that the cargo surface is reasonably level in each hold, with the height difference between peaks and troughs not exceeding 5% of the vessel’s breadth. Peaks concentrate overburden stress and create localised conditions where dynamic separation is more likely to initiate. Voids between high spots also create drainage channels that allow free moisture to accumulate. Trimming with bulldozers is standard practice for a dense ore cargo and is operationally routine for bauxite; the Group A trimming requirement simply codifies what good cargo practice already demands.

Bilge monitoring at sea

Bilge levels in holds carrying BAUXITE FINES must be monitored throughout the voyage. Rising bilge water is a warning of moisture migration. As noted, for dynamic separation the migration is upward and bilge accumulation may be slower than in classical liquefaction, but any rise in bilge levels in a BAUXITE FINES hold should prompt immediate review of the cargo condition and, if the ship is in a seaway, consideration of speed and course reduction.

The master’s right and duty to refuse

IMSBC Code Section 4.3 and SOLAS Chapter VI, Regulation 2, both preserve and in many circumstances make mandatory the master’s refusal of a Group A cargo where documentation is absent, invalid, or shows MC at or above TML. For BAUXITE FINES the specific grounds for refusal include:

• TML certificate absent or more than six months old
• MC certificate absent or more than seven days old
• MC certificate shows moisture content equal to or exceeding the TML
• Cargo visible condition inconsistent with the declaration (e.g., slurry or free water visible at surface, or can test positive)
• Rain has fallen on open hatches after the MC sampling date and resampling has not been done

A master who loads on a valid but incorrect TML (for example, one based on the wrong test method) is in a legally complicated position. The Code requires the prescribed test method; a certificate from a non-prescribed method is not valid in law even if the number happens to be similar to a valid result.

Cargo handling and stowage

Loading

Bauxite loads by shiploader conveyor in most major export ports. The loading rate for supramax and panamax vessels at major Guinean and Australian terminals runs 4,000 to 8,000 tonnes per hour. A typical 50,000-tonne supramax load at Kamsar completes in eight to twelve hours. Trimming with bulldozers follows loading in each hold and should be completed before the hatch is closed.

The cargo’s bulk density, 1,200 to 1,500 kg/m3, makes it a deadweight-limited commodity. A Supramax bulk carrier with a 60,000-tonne deadweight and a grain capacity of roughly 67,000 m3 will reach its marks on bauxite while still having a substantial volume of hold space empty above the cargo. That empty space is above the trim line and is not a problem for coarse Group C material, but for BAUXITE FINES it means the hatch opening is above the cargo surface, which increases the area exposed to rain if loading is interrupted.

Ventilation

BAUXITE and BAUXITE FINES do not generate gas during carriage and do not self-heat. Ventilation of the cargo holds during the voyage follows standard practice for a non-hazardous ore cargo: hatches remain closed and weather-tight; any required bilge-well inspection follows the confined-space entry procedures of SOLAS Chapter XI-1. There is no surface ventilation requirement and no hold-atmosphere monitoring obligation.

Dust

Bauxite, particularly Malaysian and Indonesian laterite, is dusty at the stockpile and at load. Fine red-brown dust rises during loading and can coat the deck and adjacent surfaces. This is an environmental and personnel protection issue at the load port, increasingly subject to local regulations. At the discharge port, grab discharge of bauxite generates significant dust at the crane drop point. Chinese ports handling bauxite have in several cases imposed dust-suppression requirements on the carrier, including pre-wetting of the surface layer before grab discharge begins.

Discharge

Bauxite discharges by grab-fitted shore cranes at most receiving ports. Major Chinese bauxite import terminals at Qingdao, Yingkou, Bayuquan, and Zhanjiang handle Supramax to Capesize vessels with grab cranes rated for dense ore. The cargo is cohesive enough to grab cleanly without significant spillage when in normal solid condition. Discharge is slower per grab-cycle than a coarser, harder ore because bauxite resists the grab opening, but the density means each grab is heavy. A standard 12-tonne grab on 50,000 tonnes delivers completion in roughly 18 to 24 ship hours, depending on crane complement and crane rate.

Bilges should be pumped and cleared before discharge begins. Any residual bilge water containing fine bauxite should be handled per MARPOL Annex V and local port regulations before discharge of the cargo. Bauxite residue in the hold after discharge requires mechanical sweeping; the fines adhering to the tank top and lower frames can be significant after a wet voyage and should be removed before the next cargo is booked.

Bauxite in context: the IMSBC Group A record

Bauxite was not the first commodity to force an IMSBC schedule revision after casualties. The Group A regime as a whole developed through a series of losses that each exposed a mismatch between the regulatory classification and the cargo’s real behaviour.

Iron ore fines from India caused the loss of the Asian Forest (17 July 2009, 24 crew killed) and the Black Rose (9 September 2009) in the approaches to Indian ports during the monsoon season. Those losses triggered the Indian inquiry that produced the modified Proctor-Fagerberg test for iron ore fines, made mandatory under Amendment 03-15 (MSC.393(95)) from 1 January 2017. The detailed treatment of that Group A schedule is in the iron ore IMSBC schedule.

Nickel ore from Indonesian and Philippine ports caused a cluster of losses from October 2010 through 2011: the Jian Fu Star (27 October 2010, 13 crew killed), the Nasco Diamond (10 November 2010, 21 killed), the Hong Wei (3 December 2010, 10 killed), and the Vinalines Queen (25 December 2011, 22 of 23 crew lost). Nickel ore liquefaction is covered in the nickel ore IMSBC schedule.

Bauxite was the third commodity to force a Group A reclassification through casualty evidence, and the Bulk Jupiter was the case that did it. The pattern is consistent: a cargo carried for years as Group C or Group B, a cluster of losses or a single large-casualty event, an investigation, a working group, and a new mandatory schedule at the next amendment cycle. The cargo liquefaction article puts all three in the same framework and traces the TML controls that apply to each.

For mineral concentrates from wet beneficiation, the Group A liquefaction concern operates through the same pore-pressure mechanism but without the dynamic-separation element specific to clay-bearing fine bauxite.

The bauxite trade after Bulk Jupiter

The Bulk Jupiter loss had immediate commercial effects beyond the regulatory. Malaysia suspended bauxite mining in January 2016 in response to environmental pressure and the reputational fallout from the casualty. The ban was extended several times, and Malaysian export volumes remain a fraction of their 2014 peak. Guinea stepped in to fill the supply gap and has not stepped back: its export volume grew from roughly 20 million tonnes in 2014 to over 105 million tonnes a decade later, and Guinea now supplies approximately 60 to 65% of China’s bauxite imports.

The consolidation of supply into Guinea created a qualitatively different cargo profile for the trade. Guinean laterite from the Boké basin is typically coarser and drier than Malaysian material, loads from well-maintained large-scale terminals, and is the standard Group C cargo in the trade. But the amendment that created BAUXITE FINES applies globally, and any bauxite from any origin that meets the particle-size criteria requires Group A treatment.

Brazilian fines-fraction material, Indonesian material when export bans are periodically lifted, and fines produced by mechanical handling at any origin can all meet the BAUXITE FINES criteria. The shipper’s obligation to test and classify applies regardless of the reputation of the origin. A Guinean bauxite that has been rehandled through a fines-generating crusher or that contains a finer-screened fraction from a different mine area is not exempted by its country of origin.

Limitations

This article draws on the IMSBC Code as amended by Resolution MSC.500(105) (Amendment 06-21, mandatory 1 December 2023) and Resolution MSC.539(107) (Amendment 07-23, mandatory 1 January 2025). Amendment 08-25 (MSC.575(110)) applies voluntarily from 1 January 2026 and becomes mandatory from 1 January 2027; masters and shippers must verify whether a further amendment has altered the schedule applicable to a specific shipment.

The TML for a specific bauxite fines consignment is a property of that consignment tested by an accredited laboratory on a representative sample. Two shipments from the same origin with different processing histories can have TMLs differing by several percentage points. The modified Proctor-Fagerberg test prescribed for BAUXITE FINES must be used; a certificate from a different method is not valid. A TML certificate from an accredited laboratory does not guarantee the test was performed on a representative sample of the actual cargo to be loaded; sampling methodology is itself a point of failure documented in P&I club analyses.

The Bulk Jupiter investigation conclusions, including the finding that dynamic separation was the probable cause, are based on the evidence available to the Bahamas Maritime Authority. The vessel sank in relatively shallow water (70 to 80 metres) and was inspected by divers, which provided more physical evidence than many deep-water casualties. The “probable” qualification reflects the inherent limitations of a post-capsize investigation, not significant doubt about the mechanism.

The dynamic-separation mechanism has been formally defined in the IMSBC Code since Amendment 06-21, but the scientific understanding of its kinetics under different cargo conditions, moisture levels, and motion profiles continues to develop. The modified Proctor-Fagerberg test was designed to be conservative relative to the observed dynamic-separation threshold, but no standard test can fully replicate every combination of cargo heterogeneity and sea-state loading a bulk carrier may encounter. Compliance with the TML requirement is the legal and practical defence; it does not eliminate the hazard, but it reduces it to a level the Code considers acceptable for carriage on ordinary bulk carriers.

Flag state implementation of IMSBC amendments may lag the IMO mandatory date, and the competent authority of the load port may apply additional or different requirements. Masters should verify the requirements applicable to the specific cargo, load port, and flag state for every voyage. The casualty accounts in this article draw on published investigation reports and IMO circulars; they are cited at the level of detail available in those sources.

See also

Related calculators

• IMSBC cargo finder
• IMSBC TML moisture check
• IMSBC liquefaction Group A calculator
• IMSBC bauxite fines schedule data
• IMSBC bauxite schedule data
• Iron ore fines moisture calculator

Related wiki articles

• IMSBC Code
• IMSBC Group A cargoes
• IMSBC Group C cargoes
• Cargo liquefaction: TML, FMP, and Group A controls
• Alumina: IMSBC Code schedule and carriage
• Mineral concentrates IMSBC schedule
• Iron ore IMSBC schedule
• Nickel ore IMSBC schedule
• Bulk carrier
• Cargo hold preparation standards