Special precautions for handling bulk coal

Fig: Bulk Coal Loading

The ship shall be kept upright during loading of this cargo. This cargo shall be so trimmed to the boundaries of the cargo space that the angle of the surface of the cargo with horizontal plane does not exceed 25 deg. This cargo shall be kept as dry as practicable. This cargo shall not be handled during precipitation. During handling of this cargo, all non working hatches of the cargo spaces into which the cargo is loaded or to be loaded shall be closed

Fig: Bulk Coal Discharging

Vessels shipping coal should at all times carry on board instruments for measuring methane, oxygen and carbon monoxide gas concentrations, so that the atmosphere within the cargo space can be monitored. The instrument should be regularly serviced and calibrated so that it can provide the crewmembers with reliable data about the atmosphere within the cargo space. Care needs to be exercised in interpreting methane measurements carried out in the low oxygen concentrations often found in unventilated cargo holds.

The catalytic sensors normally used to detect methane rely on the presence of sufficient oxygen for accurate measurement. This phenomenon does not affect the measurement of carbon monoxide or measurement of methane by infrared sensor. However, additional guidance should be sought from the manufacturer of the instrument.

An instrument required for measuring methane, oxygen and carbon monoxide concentrations should be fitted with an aspirator, flexible connection and a length of tubing, thus enabling a representative sample to be obtained from within the square of the hatch.

Stainless steel tubing approximately 0.5m in length and 6mm nominal internal diameter with an integral stainless steel threaded collar is often preferred. The collar is necessary to provide an adequate seal at the sampling point.

A suitable filter should be used to protect the instrument against the ingress of moisture as recommended by the manufacturer. The presence of even a small amount of moisture would compromise the accuracy of the measurement.

Avoid all unnecessary handling, even the removal of wet clothing. If handling is necessary, then it should be as gentle as possible. Enclose the survivor in a plastic bag or blankets or preferably both. It is important that the head, but not the face, is well covered. Place in a warm area with a temperature not exceeding 22øC. Never attempt to give any fluids by mouth to an unconscious casualty.

Bilge precautions: Bilge wells shall be clean, dry and covered as appropriate, to prevent ingress of the cargo.

Hazard

Coal May be create flammable atmospheres, may heat spontaneously, may deplete the oxygen concentration, may corroded metal structures. Can liquefy if predominantly fine 75% less than 5 mm coal.

Weather precautions: Unless the vessel is specially constructed, the Moisture content of the cargo shall be kept less that TML during voyage.

Stowage & segregation: This Cargo shall be separate from goods of classes 1,2,3,4,5 n IMDG

Ventilation: Following the special precautions in IMDG

Hold cleanliness: Clean and Dry as relevant to the hazards of the cargo.

Special Precautions

Coal emitting methane
Self-heating coals
Gravity-field self-unloading bulk carrier

Carriage

In respect of coals liable to spontaneous heating, the Code recommends that the hatches should be closed immediately after completion of loading in each cargo space. The atmosphere in the cargo spaces should be monitored and, if the carbon monoxide level shows a steady increase then the cargo spaces should be completely closed down. The covers could also be additionally sealed with suitable sealing tapes.

Discharge: No special requirement

Clean up

In the case that the residues of this cargo are to be washed out, the cargo spaces and the other structures and equipment which may have been in contact with this cargo or its dust shall be thoroughly swept prior to washing out. Particular attention shall be paid to bilge wells and framework in the cargo spaces. The fixed bilge pumps shall not be used to pump the cargo spaces, because this cargo may make the bilge system inoperative.

Coal Loading Port - Tanah Grogot; Berau; Tg. Buyut; Sampit/Indonesia
Coal Discharging Port - Paiton / Indonesia; Rayong, Ko Si Chang/Thailand

Case Study

(Britannia P and I Club Volume 17: number 2: June 2010)
An incident on board one of member vessel in Indonesia highlights the risks of self-heating and spontaneous combustion of coal cargo, as well as the hazards of loading from barges.

Most Indonesian coal has a maximum particle size in excess of 7mm and accordingly the transportable moisture limit (TML) is not normally a problem. Fire experts, Messrs Burgoynes, have dealt with 18 incidents involving overheating coal off Kalimantan (Indonesian Borneo) in the last two years. The majority of cases involved the loading of low-grade coal with temperatures in excess of 55°C. They advise that there are apparently a number of operators who are shipping coal without following accepted industry good practice. Such operators may mis-declare cargo as not being prone to self -heating or provide no details of the self -heating or methane-emitting characteristics of the cargo.

Unless loading is closely monitored the problems are usually only seen after the cargo has been loaded. Once loaded, it is difficult to arrange for the removal of the coal due to the lack of suitable facilities, i.e. floating cranes and empty barges, in the region. The Master should insist that the shipper provides a cargo declaration that is consistent with the requirements of the International Maritime Solid Bulk Cargoes (IMSBC) Code, and should not load cargo without having received the required declaration. The IMSBC Code requires the shipper (or agent) to provide cargo details, including:

moisture content
sulphur content
particle size
information on whether the cargo may be liable to emit methane or self-heat, or both.