Yellowknife (Aug 18/06) - Technical aspects of the proposed Mackenzie Valley pipeline were the focus of discussions as a second series of regulatory hearings kicked off in Yellowknife Tuesday.

The seven member Joint Review panel heard about how climate change, melting permafrost and water courses could affect the $7.5 billion pipeline. The current proposal would see the pipe run underneath streams and rivers, and several factors which could affect the structure's integrity.

Environment Canada's Barrie Bonsal asked for clarification from Imperial Oil - lead proponent of the project - on the company's plan to monitor the pipeline for breaks.

Responding on behalf of Imperial was Chris Heuer.

"We're interested in the integrity of the pipeline and that includes not just knowing ... the current state of the pipeline," he said. "We also want to know why the pipeline may be deforming."

Imperial said it will employ pigs - rubber, cork-like devices which will travel inside the pipeline periodically - to monitor the structure.

The Department of Fisheries and Oceans (DFO) raised concerns about how excavated dirt will affect fish populations in rivers and streams.

Imperial's Rick Luckasavitch said programs are in place to deal with the matter, but the company was open to additional information that would alter its approach.

"I'm not in a position to say: 'Gee, we've got that right'," said Luckasavitch. "Our plan is to work with regulators, including DFO."

According to Imperial, 470km of pipe will be built in continuous permafrost while the remaining 930km will be in discontinuous permafrost. The pipeline will also traverse 643 water crossings and 829 slopes.

Imperial noted it has based its overall pipeline design on a projected 25 to 30 year lifespan.

The Joint Review Panel is one of two regulatory bodies, including the National Energy Board, looking into the proposed pipeline. Its members are examining the social and environmental impacts on the megaproject, which would siphon natural gas from the Beaufort Delta into northern Alberta.