Very Large Ore Carrier, the Stellar Daisy, mysteriously vanished off the coast of South America en route to China. Picture: MarineTraffic.com

The 266,000 tonne South Korean bulk carrier Stellar Daisy disappeared off the coast of Uruguay en route from Brazil to China, hours after issuing a distress signal on Friday.

The ship was carrying 24 people, including 14 Filipinos and eight South Koreans. Two Filipino crew members found floating on life rafts were rescued on Saturday and the search continues for the other 22.

An oil slick detected 3700km off the coast indicated that the 322 metre vessel had probably sunk, according to a statement issued by the Uruguayan Navy.

The Stellar Daisy was reportedly transporting a cargo of iron ore from the Ilha Guaba terminal in Rio de Janeiro to China, where the demand for ore has exploded as the economy grows.

The Marshall Islands-flagged ship is thought to gone down some 2000 nautical miles off the port city of Montevideo.

On March 31, a crew member sent a text message to the shipping company’s Seoul stating the vessel was taking on water and was sinking. When the company tried to contact the vessel, but all attempts failed.

Uruguayan Navy and Brazilian authorities were alerted when an emergency satellite signal had been received from the Stellar Daisy, the Shipping Herald reported.

A search and rescue operation was launched in the area of the signal. Four nearby commercial vessels were asked to assist in search effort and the Brazilian Air Force dispatched a plane from Rio de Janeiro.

On April 1, the Uruguayan Navy reported finding an oil sheen and flotsam along with a “strong smell of fuel”. A short time later two life rafts from the Stellar Daisy were located by one of the commercial vessels.

DID A CHEMICAL CHANGE IN THE ORE CARGO LEAD TO DISASTER?

Early reports suggest that the Stellar Daisy, which is classified as a Very Large Ore Carrier, lost stability and quickly sank.

But why?

One theory being floated, published in the Shipwreck Log today, is that the ore shifted, causing the vessel to lose balance and capsize.

There have been several documented cases of ships suddenly sinking due to the liquification of iron ore and nickel ore during prolonged movement, such as bumping and shaking that occurs in bad weather.

In 2010, three ships loaded with nickel ore sunk in South East Asia, claiming the lives of 44 crewmen.

The deadly spate prompted internationally renowned maritime accident investigator Dr Ken Grant to issue a warning about the chemically volatile cargo.

“Although a cargo may appear to be dry, its core structure may contain sufficient moisture to cause liquefaction,” Dr Grant told The Australian Journal of Mining at the Company of Masters Mariners forum in Melbourne in 2011.

“It does not take much force to produce or induce liquefaction.”

Very large ore carrier Stellar Daisy is believed to have rapidly sunk or capsized. Picture: MarineTraffic.comSource:Supplied

Dr Grant said the both mariners and law makers were dangerously ill-informed about the properties and behaviour of iron ore and nickel ore.

“It’s not helping make decisions on the ground and liquefaction is very poorly understood and often just totally disregarded,” he said. “People just don’t accept that their cargo is going to liquefy. We need to better understand the properties of nickel ore.”

In 2012, Vietnamese cargo ship Vinalines Queen carrying 23 crew men and 54,000 tonnes of ore vanished without a trace in bad weather off the Philippines.

One crew member was rescued and told investigators the vessel had sunk.

Investigators later concluded that that the ore cargo could have been liquefied in the shaking that the ship was subjected to by strong waves and winds, the Thanh Nien News reported.

When it tilted to one side, the liquefied ore could have also gathered on that side and tipped the balance irrevocably, the investigators said.

Investigators said conditions would have been even more perilous in the event crew had failed to close the ship’s hold properly, allowing water brought by high waves to enter and liquefy the ore.

However, the sole survivor of the tragedy, 31-year-old Dau Ngoc Hung, told inspectors that he was in charge of securing the hold and insisted conditions were “normal” before the ship sunk.

Meanwhile, the search for the Stellar Daisy and its 22 missing crew members continues.

The Stellar Daisy disappeared en route from Brazil to China with a large cargo of ore. Picture: MarineTraffic.comSource:Supplied