Moving an Arctic city sideways

Inside the Arctic circle, in the far north of Sweden, there is a city on a hill. Kiruna is a glittering place - even your breath sparkles, turning crystalline as you exhale.

Looming over the city are the mountainous slag-heaps of the LKAB mine and, in the early hours of every day, Kiruna shudders and trembles as nearly 100 tons of high explosives detonate more than 1km underground, liberating thousands of tons of iron ore from the heart of the mountain.

You can feel the blast more than you hear it - feel it in your chest and through the soles of your feet.

The seam of magnetite runs from the top of Kiruna mountain, deep into the rock below, sloping underground towards the city.

But the hollowed out earth is shifting now, cracking under Kiruna as the mountain slips sideways.

So, they have decided to move the city, 4km (2.5 miles) down the road.

Frozen landscape

Some buildings will be torn down and replacements built. Others will be dismantled, stone by stone, and reassembled in a new landscape.

And some, like the magnificent wooden church, once voted Sweden's most beautiful building, will be lifted whole, and transported slowly down roads as yet unbuilt.

Ann Helen Karlstroem lives close to the mine and her home will be among the first to go.

The detonations underground sometimes shake the pictures from the walls, she says - and she worries about the cracks in the ground nearby.

"I am going to be a little sad because I thought our grandchildren could see where their parents were growing up," she says.

Her husband, Erling, just wants to make sure their new home in this city in the wilderness is as big as the old one.

He, like most people in Kiruna, are resigned to the move.

Without the mine, the city would struggle to survive.

But there is resistance from some of those who lived here first - the indigenous Sami People.

For more than 2,000 years they have herded reindeer and they say the transformation of Kiruna will cut deep into their grazing lands and the migration paths of their animals.

Hans-Goran Partopuoli learned to herd reindeer the hard way - walking and skiing long distances through a frozen landscape, to follow his animals.

Tradition versus progress

But things have changed for the Sami - they use helicopters now and all-terrain vehicles and snowmobiles.

"Why do we have to live in tepees and ski," he says, "when you know, in the shop, there are these kind of machines".

His 19-year-old daughter, Helena, approves.

She is working with him this winter, on a break from the Sami Reindeer Herding School where she studies economics and biology.

Hans-Goran provides the practical lessons, and he works her hard.

Helena perches on the back of a sledge being towed by a snowmobile and we sprint through the monochrome landscape - black trees and white snow.

The only colour comes from the young woman's traditional red and green Sami cape.

As the caravan bounces across the ice and swerves through the forest, Helena crawls back and forward along the loaded sledge, throwing handfuls of hay onto the track.

They are trying to keep the reindeer away from the mountains, enticing them to stay on the lower lands until spring.

They light a fire by the side of a frozen lake and, as we share a meal of reindeer meat and bread, Hans-Goran explains why he is so worried about the plans to move the city.

"It will make the grazing lands smaller for us," he says.

"And they are building a new railway across the path where we go with the reindeer... so that's why we are very worried about this."

To move Kiruna will take decades, but plans for the new railway are well-advanced and the electricity grid to power the new city is already in place.

Lucrative income

On a barren hillside, near a frozen lake, I stand with Lina Naesstroem from Kiruna Council, and we try to imagine it at the heart of a busy city.

"It's a huge project," she says.

"It's not just one thing we need to move, reorganise, restructure - this time it's everything - roads, railways, electricity, sewage pipes, housing, churches, hospitals, city halls, schools, kindergartens, city-centres."

The state-owned mining company will pay most of the costs and that price will be high.

But Anders Lindberg, from LKAB, says the benefits outweigh the cost.

In his Volvo estate he drives me down into the mine, along the network of roads that runs for more than 300km through tunnels in the rock.

"It is the largest underground iron ore mine in the world," he says.

They do not yet know how deep the iron ore goes and that, he says, is great for a mining company.

"We can't say how long we will be mining. It all depends on how long it will be profitable," he says.

And it is profitable enough to be worthwhile moving a city.

A hungry planet craves the iron ore that LKAB produces - Kiruna, like the rest of the world, still lives in the Iron Age.

Mike William's report on the Swedish town of Kiruna can be heard on the One Planet programme on BBC World Service on Thursday, Friday and Saturday.