A mine weighing nearly 800 kilograms located by PanGeo on the sea floor in Europe is detonated by the Danish Navy. (Submitted by PanGeo)

Moya Cahill didn't have this kind of boom in mind 12 years ago when she co-founded PanGeo Subsea, an ocean technology company, in St. John's.

Back then, as the province approached the peak of the offshore oil boom, she imagined PanGeo's remotely operated vehicles would be used by oil companies to scan the ocean floor off the coast of Newfoundland.

But these days, they're in the North Sea, off the coast of Germany and the Netherlands, helping locate live explosives left on the bottom of the ocean after the Second World War, so they can be dug up and detonated to make way for wind farms.

"The oil and gas runs through my — well, used to run through my veins," Cahill said. "And now I'm glad to say that we've really switched over to this offshore renewable sector."

Moya Cahill co-founded PanGeo SubSea in 2006, with an eye on the province's offshore oil industry. Now PanGeo works mostly in offshore renewable energy. (John Pike/CBC)

That explosion footage above shows a mine found by a PanGeo ROV being detonated off the coast of Denmark with the help of the Danish Navy.

Past weapons in the way of future energy

More than 50 million bombs, shells and detonators from World War II litter the floors of the Baltic and North Seas, according to official estimates. Those seas are also home to increasing offshore wind energy interests.

The unexploded ordnances, or UXOs, have injured fishermen in the area, getting snagged in fishing nets and brought to the surface and then exploding or leaking toxic substances.

They're now also a major safety hazard for workers building offshore wind turbines.

Cahill says the Danish navy was so happy this bomb was found, they named it the Laura Bomb, after Laura Purchase, PanGeo's lead on the survey that picked it up. (Submitted)

PanGeo uses acoustics to generate rough maps of the sea floor five to eight metres deep, Cahill said.

The companies and organizations PanGeo works for — they just wrapped up a stint with the Danish Navy — use those images as guides, sending down equipment that can dig things out of the muck and see what they are.

Sometimes they're nothing: they've found an anchor, even a relaxing seal.

It looks like it could have been a missile of some kind, but it was just a seal. (Submitted)

But more often than not, they're dangerous pieces of decades-old weaponry left over from a gruesome war, and the safest way to get rid of them is a controlled explosion far from shore, she said.

Picking up luftmines

Their acoustic scans let them pick out more mines than a traditional magnetic scan, including the tough-to-detect LMB mines, or luftmines, used by the Germans, said geoscientist Alison Brown.

She interprets the data coming up from the ROVs.

Luftmines can weigh as much as 1,000 kilograms. (Submitted)

The Luftwaffe dropped these massive, 1,000-kilogram sea mines from planes high above the water.

They're often called parachute mines, because they had parachutes attached to their tail ends.

"The reason why this mine is so elusive is because of the aluminum casing," Brown said. "It doesn't have much of a magnetic signature."

Working with history

Brown, like Cahill and much of PanGeo's young staff, never imagined she'd be using her geophysics degree to help build wind farms.

"I thought it was going to be working in mining exploration or offshore oil and gas exploration," she said.

Alison Brown is a geoscientist at Pangeo SubSea. (Sarah Smellie/CBC)

But instead of meetings with oil executives and engineers, she's getting training from experts in the weapons and history of the Second World War.

"The Germans kept excellent records of where they left all their mines and their bombs," she said. "So they look at those records and they say, 'Yeah in this area, you're going to find this type of bomb, which is so large,' and we know what to look for."

"I find it interesting that I get to clean up after World War II," said Meghan Tucker, an ROV operator who also assumed she'd be in the oil industry.

"It makes me feel good to be a part of that."

Like Cahill and Brown, Meghan Tucker, 27, imagined she'd be working in the oil and gas industry when she graduated from the Marine Institute. (Sarah Smellie/CBC)

Wind energy in Newfoundland?

Cahill says the company also gets a lot of work surveying sea floors for companies to lay the giant cables needed by the massive wind turbines offshore.

As interest in wind power spreads across the globe — lately, PanGeo has had bites from companies in Taiwan and China, she said — she sees a good future for the company in renewable energy.

Cahill says the company got its first UXO gig after a submarine owned by the Indian navy lost two missiles following a deadly explosion in 2013. PanGeo found those missiles.

She believes part of that future is in Newfoundland and Labrador.

"There's a lot of talk about offshore wind, and it balances out the other energy sectors — our hydro electric as well as our oil and gas sector," she said.

"I'm quite confident that with time we will see offshore wind firms here off the coast of Newfoundland."

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