Due to rainy season, vessels may face liquefaction problems
A major concern for ship owners and their P&I Clubs is the property of the nickel ore, which when carried in bulk, can liquefy through the motion of the ship in a seaway or vibration of the ship through main engine/on board machinery. This ability of the cargo to transform from an apparent solid state to a liquid one when the cargo has a high moisture content can have serious and catastrophic effects to the vessels stability and has resulted in vessels capsizing and sinking within minutes. This property of the cargo should not be mistaken with free surface effect (sloshing), the cargo during liquefaction undergoes a metamorphosis between a solid to a liquid to a solid, changing between these states unexpectedly and is a dynamic shift. Once the cargo has shifted it will not come back, this shift resulting in the loss of the vessels stability with resulting list or capsizing.
The general practice is to ship cargoes of nickel ore from February to May/June which is traditionally the “dry season” in the Philippines, with the “wet season” starting in late June with associated typhoons. However while ten years ago the seasons changed like clockwork, the climate has been changing and in recent years it can rain frequently in the “dry season” with typhoons as early as April.
The cargo of nickel ore is being presented for loading overall with higher moisture content than years ago. This has highlighted concerns over the standard of the tests conducted by the local mines “in-house” laboratories, recently this is becoming a real issue. The installation and operation of the testing equipment when there has been the opportunity to observe, is not properly installed in line with the IMSBC Code
.Mines have also modified their procedures where by the cone size is tampered with, this was not helped about three years ago by an “expert” from Australia assisted the mines in Mindanao, however the method taught has raised concerns with scientific experts in this field.
The ore in the area comes in three qualities
- Lateritic nickel content 0.9%
- Limonitic nickel content 1% to 1.5%
- Saprolitic nickel content 1.5% to 2%
The levels of nickel content as can be seen are low, also it should be remembered the cargo is traded per wet metric tonne (wmt) and can contain conservatively 30% water. In a typical nomination of 55,000 wmt then 16,000 tonnes will be water, in the remaining 39,000 tonnes only on average 585 tonnes of nickel will be produced.
Nickel ore cargoes, which consist of a mixture of very fine clay-like particles and rocks up to 1m in diameter (looks like land fill) makes for a cargo whose properties are not fully understood, as no complete study has been made of this cargo and the IMSBC is based on homogenous cargoes.
Club’s current concerns are the method and quality of the certificates being issued by the mines and that the nickel ore inherently is unsafe to carry and the analysis and results inadequate and not in line with the IMSBC Code.
The mining is open cast and the stock piling open to the weather then the cargo can easily become wet, while the ore is not particularly absorbent, given the nature of tropical rain (heavy) and the fact that the barges very seldom cover the cargo, the moisture content can significantly increase.
Find out more by reading Japan P&I Club’s report
Source: The Japan P&I Club