The transportation of dangerous goods by ships is a crucial aspect of waterway traffic safety. When vessels carry oil, hazardous chemicals, or dangerous goods that are flammable, explosive, toxic, etc., incidents such as fires, explosions, or major leaks can lead to severe damage to the vessel, serious environmental disasters, and significant casualties.
Since April 26, 2024, the Maritime Safety Administration of the Ministry of Transport has been conducting a nationwide special campaign to rectify safety issues in the transportation of dangerous goods by ships. This campaign focuses on the safety risks associated with carrying dangerous goods, aims to crack down on prominent illegal activities, resolutely investigate and eliminate major accident hazards, comprehensively enhance the intrinsic safety level of shipborne dangerous goods, and help build a new, integrated pattern for waterway traffic safety governance.
Copper slag is a residue from the copper smelting process and is a type of non-ferrous metal slag. As one of the primary methods for transporting copper slag, maritime transport requires special attention during cargo handling and vessel navigation to avoid waterway traffic accidents. Let’s learn about “copper slag” and the key considerations for its safe transport!
I. Cargo Characteristics
(I) Cargo Introduction
Copper slag is generally slag produced during pyrometallurgical copper smelting. It is rich in various metallic elements such as iron, silicon, copper, and zinc, and serves as a raw material in numerous fields including cement, ceramic tiles, abrasives, and glass ceramics. Copper concentrate and copper slag are two different types of cargo. Copper concentrate is refined ore and can be used as a raw material for copper smelting, whereas copper slag is the residue left after smelting copper concentrate.
(II) Cargo Transport Name and Group
Cargo Transport Name: Copper Slag
Cargo Transport Name (English): COPPER SLAG
According to the International Maritime Solid Bulk Cargoes (IMSBC) Code, copper slag belongs to Group A – Cargoes which may liquefy.
(III) Physical and Chemical Properties of the Cargo
Copper slag is generally black or reddish-brown, in granular or lump form. The cargo has high permeability, allowing water to drain quickly through voids. If the moisture content of the cargo exceeds the Transportable Moisture Limit (TML) during sea transport, it may liquefy. The cargo has a certain abrasiveness. This cargo is not flammable or has a low fire risk.
The density range of the cargo is generally 1500 to 3600 kg/m3.
(IV) Main Risks in Maritime Transport
Copper slag belongs to Group A – Cargoes which may liquefy. When transported with a moisture content exceeding the Transportable Moisture Limit, the cargo may form a free surface during vessel rolling, potentially leading to major safety accidents such as vessel listing or even capsizing, with risks exacerbated especially under winter gale conditions!
II. Cargo Management Requirements on Board
(I) Trimming
Although copper slag cargo is a cohesive cargo, the IMSBC Code has strict regulations for its trimming. The cargo must be trimmed to ensure the height difference between peaks and troughs of the cargo pile does not exceed 5% of the ship’s breadth, and the surface slopes uniformly from the hatch to the bulkhead to avoid the collapse of steep cargo slopes during the voyage.
As the stowage factor of the cargo generally ranges between 0.40 and 0.70 m3/t, particular attention must be paid to spreading the cargo evenly across the tank top to distribute the weight uniformly if the intended cargo’s stowage factor is equal to or less than 0.56 m3/t; otherwise, the tank top may be overstressed. During navigation and handling, due care must be taken to ensure the cargo is not piled in a manner that overstresses the tank top.
(II) Dust Protection
1. Take appropriate precautions to prevent the dust of this cargo from entering machinery spaces and living quarters.
2. The bilge wells of the ship’s cargo holds should be protected to prevent cargo ingress.
3. If necessary, personnel likely to be exposed to the dust of this cargo must wear gloves, goggles or other equivalent eye protection against dust, and dust filter masks.
4. Prevent dust from contaminating equipment during cargo handling.
III. Control of Cargo Moisture Content
As the cargo, when transported in bulk, belongs to Group A and has characteristics prone to liquefaction, attention must be paid to the control of its moisture content during cargo handling and vessel navigation.
1. The moisture content of the cargo must be maintained below the Transportable Moisture Limit (TML) during loading operations and throughout the voyage.
2. If all the cargo in a cargo space is to be discharged at the same port, the cargo in that space may be discharged during precipitation.
3. Ensure the moisture content of the cargo is not affected before or during loading operations. The shipper must re-sample and test the moisture content of the cargo before or during loading if any of the following circumstances occur:
(I) Situations such as precipitation may cause an increase in the cargo’s moisture content or changes in its other properties;
(II) The master has sufficient reason to believe that the cargo intended for loading does not match its moisture content certificate.
4. During cargo handling, all hatch covers of spaces not in use that are loading or intended to load this cargo must be closed.
5. During the voyage, the vessel must pay attention to regularly draining water from the bilge wells.
IV. Emergency Response
During the voyage, the surface condition of the cargo must be checked regularly. If free liquid or liquefied cargo is observed on the surface of the cargo during the voyage, the master must take appropriate measures to prevent cargo shift and the danger of vessel capsizing, and consider seeking refuge in a place of shelter.
