MIAMI, May 19: US deep-sea treasure hunters said on Friday they retrieved 17 tonnes of silver coins from a shipwreck, saying that the find is the largest of its kind, worth hundreds of millions of dollars.

Odyssey Marine Exploration said the coins and other artifacts were found on a “colonial” period shipwreck in the Atlantic Ocean, but maintained a shroud of secrecy over the exact location, citing security and legal reasons.

The artifacts include over 500,000 silver coins weighing more than 17 tonnes, hundreds of gold coins, as well as worked gold, said the Tampa, Florida-based company.

“It is believed that this recovery constitutes the largest collection of coins ever excavated from a historical shipwreck site,” the company said in a statement.

It also said it expected the shipwreck would eventually become one of the most publicised in history.

An expert consulted by the company recommended offering the silver coins at retail prices ranging from a few hundred dollars to $4,000 each, depending on the condition, date and origin.

“The gold coins are estimated to bring substantially higher numbers,” the company said.

Odyssey indicated it had used a tethered underwater robot, also known as remotely operated vehicle, in the salvage operation, but it jealously guarded information about the site and identity of the shipwreck, which it code-named “Black Swan”. “For site security and legal reasons, we are not prepared to give the location, depth or any other information about the site,” the company said.

“We have some interesting evidence that tends to point to a specific shipwreck, but we do not intend to discuss this publicly until we have had a chance to review contemporary records and conduct extensive analysis of the artifacts and coins that have been recovered to date,” Odyssey said.—AFP