Richard Gleeson
Northern News Services

Yellowknife (May 29/02) - The same primordial permafrost forces that misshape Northern highways are at work on Northern runways.

This year the Department of Transportation is attempting to address an area on one of the Yellowknife airport runways that has proven particularly troublesome.

"A runway is like a short, very wide road and suffers from the same geotechnical problems as roads," said department engineer Laurin Trudel.

Slowing down is always an option for those who encounter rough sections of road. That's a choice not available to pilots landing passenger jets.

"For an aircraft travelling at high speeds, you don't want to have a bump, for safety reasons, for comfort and also because it's hard on the equipment," said Yellowknife airport manager Michel Lafrance.

Previous test drilling and ground penetrating radar has revealed ice lenses -- mixtures of clay and water -- on the troubled runway, the shorter of the airports two landing strips.

Lafrance, who took on the job of airport manager in February, said one potential solution to the lens problem is replacing the ice/clay lenses with an inert foam.

The work will likely be performed later this summer and will leave the airport to cope with just one runway. Lafrance said that will cause no disruption of service. It's something the airport does each year when the runways are resurfaced.

The government is calling for proposals for a study to develop a better picture of groundwater and permafrost beneath the runways.

According to the terms of the proposal, you don't have to dig far down to run into either. The groundwater is 1.5-1.8 metres below the tarmac and the permafrost about three metres down.