The Arctic highway

16 abril 2007

Located in Canada's Northwest Territories, the road from Tibbitt to Contwoyto is considered one of the most dangerous routes in the world. The Denison's road - as it is also known - stretches 600 kilometres into the Arctic territory and is the main supply route for the giant diamond mines in the North. The main danger is that 85 percent of the road lies over frozen lakes, so ice can break at anytime and swallow the trucks.

The road typically opens early in February and closes early in April, the only months when the ice thickens enough and it is capable of supporting 70-ton Super B Train articulated trucks. To operate the mines, 300,000 tons of fuel, explosives, steel and concrete must be hauled in over the ice each year.

The Winter Ice Road is a real challenge for engineers and drivers. A one-way trip to Lupin mine takes about 20 hours, and average ice thickness is usually about 125 centimeters. Truckers driving in this road are veterans who risk their lifes. Many of them forgo seatbelts; if the surface gives way, a trucker will have mere seconds to jump clear.

Diamonds beneath the ice

The Winter road services mines that tap into rich deposits of diamond-bearing kimberlite. Since the first samples were found here in 1991, Canada has become the world's third largest producer by value (after Botswana and Russia).

In 1991, the first economic diamond deposit was discovered in the Lac de Gras area of the Northwest Territories. Canada became a diamond producer in October 1998 when the Ekati diamond mine opened about 300 kilometres northeast of Yellowknife. By April 1999, the mine had produced one million carats.

In the following pictures you will see how Diavik mine is connected to land by ice in the winter, and how it becomes and island again in the summer:

Mortal cracks

During operations, the Diamond mines transport approximately 5,000 truckloads of supplies to the site annually. Every single drive can be the last for the truckers. According to Popular Mechanichs, the most recent fatality in the Northwest Territories was a 23-year-old who was plowing an ice road near Yellowknife; he drowned when his truck broke through. In 2000, a Nuna worker's plow plunged through the ice on the Tibbitt to Contwoyto road, and though fellow workers pulled him clear, the shock of frigid water and freezing air triggered a fatal heart attack.

As you can see in the next video, as a laden truck moves over ice, it creates a shallow depression all around it and the displaced water forms pressure waves under the surface. One of the most dangerous places for the truck to travel, is approaching a shoreline portage. With the wave under the ice moving ahead of the truck and approaching the shallows of the shoreline, the hydraulic effect of the wave can lift and blow-out the ice. The truck must approach this point at a very slow speed.

A security challenge

Every day, a crew drives along the road, generating a profile of ice thickness with ground-penetrating radar. They drag an antenna, which sends 400-MHz radio waves down into the lake. A computer calculates the ice thickness based on the time it takes the signal to return from the ice-water interface.

When they find a crack, road managers must come up with creative solutions. If the crack is big enough, engineers try to find a way to go around it or they simply detour the road for a few miles. As you'll see in the next video they also use to lay down some kind of "rig mats", a lattice of steel and wooden beams, and frozen it into the ice to bridge the weak spot.

Finally, and if that weren't enough, global warming is affecting these territories and making the ice thinner. Last year, Canada experienced its warmest winter on record, and the Northwest Territories felt the biggest temperature anomaly in the country, with winter 7.4 C above average.

The ice didn't thicken enough to bear heavy traffic until March and hundreds of tractor-trailers full of cargo sat idle in parking lots in the city of Yellowknife.

More info, sources and pictures: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Wanna digg this?

All the sample videos in this post belongs to the documentary "Ice road truckers" shown at History Channel.