The German Surface Raider Orion, which crossed the Pacific from Cape Horn, was at the time laying hundreds of mines across the northern approaches to New Zealand and around the Australian Coast.

On the morning of June the 19th, the S.S. Niagara of 13,415tns exploded a mine laid by Orion, the Niagara reported firstly an explosion in one of her forward holds and that her engines were disabled, the explosion caused her forward hold to flood and subsequently the Niagara sunk.

Niagara sank in deep water at a depth of 438 feet, in the ships strongroom was stowed nearly eight tons of gold ingots packed in 295 boxes and valued at 2,500.000 pounds being shipped to the United States. The ultimate recovery of the greater part of the gold was one of the most remarkable operations of its kind ever carried out.