A better way to build roads in the far north

In August, Transport Minister Marc Garneau pledged more than $50 million to undertake preliminary studies for a 700-kilometre gravel road from Yellowknife, Northwest Territories, to Bathurst Inlet, Nunavut. Northerners have waited a long time for an all-season transportation corridor through the central Arctic. And a port at Bathurst Inlet has been on their wish list for decades; mining companies have rich deposits whose development is held up only by the lack of access. The challenges of building an all-season road across this area of continuous permafrost are significant, however, and the estimated costs are wildly lowballed.

Still, something has to be done. The diamond mine bonanza is all but over and pressure is mounting to sustain the economies of the Territories. A new road-building approach for the North may actually offer real hope beyond being a tantalizing election goody.

The estimated cost for the road is reported to be $1 billion. Recent experience in Manitoba and on the Inuvik-Tuktoyaktuk road reveals that on average such roads cost $3 million per kilometre. Hence a 700-kilometre road would in fact cost

well over $2 billion. Plus, to build a port at Bathurst Inlet could easily add another $1 billion. These costs do not include the road maintenance that is becoming more of a problem as permafrost melt becomes more widespread.

Continuous permafrost does not mean the ground is permanently frozen. Every summer an active layer on the surface melts. But in recent years this active layer has been getting deeper. Any road built across the tundra therefore has to be constructed with great care — and with an eye to keeping the permafrost from melting further. The problem begins where the shoulders of the road meet the natural landscape. The soil begins to melt further on both sides until the melt meets under the road. At this point, ice buried in the permafrost melts and the land slumps under the road. Lots of examples already exist of all-season northern roads with stretches that look like roller-coasters.

At the recent Northern Transportation Conference at the University of Manitoba, the aptly-named Daniel Blizzard, who is in the business, described a less expensive, more sustainable road technology for the north that uses what are sometimes called “rig mats.” Over the past 20 years, engineered wooden road sections have been developed for use in wet lands and permafrost areas. These wooden roads are used to carry heavy equipment and tractor-trailers to oil rigs or to support construction along rightsof-way for oil pipelines and electrical transmission lines. The wood is untreated, but when used on marshy ground, especially in the North, deteriorates only slowly.

Blizzard’s education in this field comes from his grandfather, Alfred Blizzard, Sr., who managed eight sawmills in Scotland during the Second World War. These sawmills provided large timber-type mats and bridges that were used to provide access for tanks and military equipment leading up to D-Day. Grandson Daniel’s interest has evolved into a sophisticated timber mat business today.

Rig-mat roads have several advantages that could be applied on the proposed corridor. First, they minimize surface disturbance. The mats are laid out over swamps and muskeg with no subsurface preparation. Second, their wooden surface helps insulate the ground and sustain the frozen soil beneath it. And there are no shoulders where melt can take hold. On the other hand, anecdotal evidence of these advantages needs to be quantified and confirmed by formal engineering analysis.

Rig-mat roads are usually temporary and are removed when a project is finished but, in the Arctic, if traffic on them is restricted to rubber-tired vehicles, they could easily last 25 years or more, and allow speeds of 45 to 55 kilometres and hour. The wooden sections are light relative to a gravel road, which makes them much easier to use for crossing wet areas. A mixed solution is also possible: traditional gravel construction where rocky outcrops exist, with rig-mat roads to traverse the tundra between them.

Rig-mat roads are much less expensive than gravel roads, especially in places lacking local gravel supplies. In many parts of the Arctic, gravel has to be transported considerable distances and in very large quantities to build road foundations. By contrast, rig mats can be carried on flatbeds and moved along a road as it is built. No foundation is necessary, the rig mats settle into the surface and “float” on the muskeg, swamp and marshy areas. Rig mats may reduce costs by as much as two-thirds and allow the proposed corridor with the $1 billion budget.

Trying to replicate southern gravel roads over the melting permafrost is a fool’s errand of the first order. Rig-mat roads are a more appropriate technology that is sustainable, flexible and affordable.