Malcolm Gorrill and Terry Halifax
Northern News Services

Yellowknife (Mar 13/00) - They can act as a sort of bridge over troubled waters, but ice and winter roads need maintenance.

Les Shaw, superintendent for transportation for Fort Simpson, is responsible for the winter road going from Wrigley to Tulita. The road goes over land but features ice bridges.

"We maintain them as required," Shaw says. "If the road's put in properly, generally you only need the grader on it every couple of days."

The person operating the grader wings snow from the sides onto the road to provide a crust.

"He'll pull just a bit of snow across, and then he drags a couple of big rotor wheels behind him, and that smooths the surface out," Shaw says.

"Overflow is one of our biggest problems. Overflow is water seeping out of lakes that are higher than the road. It tends to follow the terrain," he says.

"It finds its way out in areas where the road is and it'll create pools of water, which deteriorates the surface of the road. People tend to get stuck in it.

"So a lot of times we have to go out and repair that. Repairing it means putting a culvert in or blocking it off, so (the water) goes somewhere else."

Shaw points out the amount, or depth, of the ice determines the maximum weight allowed on these roads.

"We have a schedule for testing," he says. "We do it two ways. We use a method here of just auger, and we measure the ice and we do it at 100-foot intervals.

"We have three lines that we check, one at the edge, one on the centre and one on the outer edge."

Shaw says, "We use the lowest measurement we get on the bridge for the actual strength. A bridge is only as good as its weakest link, just like a chain."

Shaw says there is another way to measure ice depth.

"We don't have a unit over here. They use it for the Fort Providence ice bridge, which is called sub-surface interface radar," he explains.

"It just recognizes the different qualities between water and ice, so it gives you a pretty good idea what your depth is. And it's a lot faster."

With a laugh, Shaw says, "but it's an expensive little unit."

They sell for about $25,000 each.

"Henceforth, we don't have a lot of them around," Shaw says.

Meanwhile, regional superintendent Art Barnes said the wear on the ice roads is not so much a consideration as the cracking caused by the big trucks.

"The more heavy load traffic you've got, the more cracks and the more flooding and maintenance you have to do to keep the road safe," Barnes said. "The ice bends every time a load goes over it, so you get reaction from that bending in the form of cracks."

Kirk McLellan, logistics manager for Echo Bay Mines, said the Lupin road will stay open as long as the weather stays cold.

"It's been a funny year, so I'd like to hope we can run it that late to accommodate Diavik, but at the end of the day, if Mother Nature starts heating things up, we have to close it down."

"When the sun stays up later it starts getting hotter and when that happens, the portages start getting slick and the ice starts to melt and when that happens, they start running at night only," McLellan said. "We're really at the mercy of Mother Nature."