It was scallops Paul Lunjevich was looking for when he drove along Ruakaka Beach, but instead he found a Navy training mine in the surf.

At first from a distance, he thought it was a seal in the rough surf conditions but as he drew closer it became obvious it was a large black ball with spikes.

He parked up, left his uncle Russell in the ute, and went for a closer inspection of the unusual object about 9am yesterday.

"It was a bit rusty, with four spikes, and had a hook on the top," Mr Lunjevich said.


The 36-year-old whipped out his smartphone and typed "boat mine" into search engine Google. A list of mine photos appeared. "There were heaps that didn't look like it, but one did."

He decided it was time to alert the authorities. Constable Anthony Rogers, of Ruakaka, arrived and, after a quick assessment, decided to call in the Auckland-based bomb-disposal squad.

The mine created a fair amount of interest among people drawn to the beach in search of scallops, and the police officer ensured no one got too close.

Once the bomb squad arrived it quickly established it was a training mine and there was no risk of it exploding. Due to an incoming tide, it was decided to tow the mine out of the surf. The squad emptied the water out of it and it was taken to the Ruakaka Police Station, where Navy staff will collect it.

Lieutenant Commander Greg Camburn, of the Navy operational dive team, said the mine was used during diver training in Tauranga Bay in June. Twelve mines were used as part of the training phase but, in stormy conditions and two-and-a-half metre swells, the course was called off on June 25.

Ten mines were located but two were not.

Commander Camburn said of the one that drifted to Ruakaka: "We are a bit surprised it has travelled so far."

Locals at Tauranga Bay and the local policeman were alerted to the two missing mines at the time.

Commander Camburn said the Navy used the Northland coastline frequently for training. The Navy would be able to re-use the mine.