Enbridge says it will spend millions of dollars testing the integrity of the Line 9 pipeline this year ahead of a proposed reversal of the line's oil flow.

The company will spend about $160 million on "integrity digs" on the line, which cuts through Flamborough as it runs from Sarnia to Montreal. The digs will search for flaws that could cause pipe damage in the next few years, and the company will share the results, said spokesperson Ken Hall.

Hall explained the planned work to the line in a presentation at the Hamilton Conservation Authority (HCA) annual general meeting Thursday. The line from Sarnia to Westover is referred to as Line 9A, while Line 9B runs from Westover to Montreal.

Enbridge has already received approval to reverse the flow of Line 9A. It has applied to the National Energy Board (NEB) in a controversial bid to reverse the flow of 9B. A hearing is scheduled for the week of Aug. 26. Opponents worry the flow reversal could rupture a pipe and cause a spill in an environmentally sensitive area such as the Beverly Swamp in the headwaters of Spencer Creek, Hamilton's largest watershed.

A large amount of the oil in the pipeline will come from the Bakken formation, which is located in parts of Saskatchewan and North Dakota, Hall said. The line will carry mainly light crude, he said, although it could also carry diluted bitumen.

Enbridge can make the integrity data available, Hall said during the presentation. Coun. Brian McHattie, who was re-elected as HCA chair Thursday, said he's "looking forward to seeing that information."

"I think I feel better," he said after the presentation. The integrity data is "critical because this is a 40-year-old pipeline."

The integrity work is ongoing and will take the next year and a half, Hall said. Enbridge is still determining how many digs it will do on the Ontario portion of the line, but the Quebec portion requires about 150.

If Hamilton city council opposes the line reversal, it can apply for intervener status at the August hearing.

Council will get a report on March 20, McHattie said. He's not sure if that will include a vote to intervene.

"My sense is that council is pretty satisfied by what they're hearing from Enbridge," he said.

HCA vice-chair Jim Howlett voice concern over the plan. Enbridge transfers 300,000 barrels of oil per day through the pipeline, which he worked out to be about 20 barrels per second.

Enbridge estimates it takes three minutes to turn off the flow in the event of a spill.

But "three minutes at 20 barrels per second is a lot of oil," Howlett said.