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Engineer: Grand Forks' slag pile shows no signs of movement

According Interior Testing Services, there is no movement of the City of Grand Forks' slag pile.

Late in 2012, a concerned resident informed the City of Grand Forks that the cracks at the south end of the city slag pile were widening.

At a Committee of the Whole meeting on April 2, Scott Shepherd with Urban Systems and Peter Hanenburg with Interior Testing, addressed the issue.

“The biggest driving force that we were aware of at the time was Overton Creek; that seasonally it flows into the slag pile up top and water can be a potential trigger for landslides,” said Hanenburg. “The biggest issue raised is, ‘What happens in the event of a large scale slope instability slide into the Granby River, what would that do?’”

On behalf of the city, Shepherd and Hanenburg took a look at the matter, which resulted in two recommendations: monitor the slag pile or divert Overton Creek.

In regards to the first recommendation, the slag pile has been monitored for movement for over a month by Interior Testing Services.

“In the last month of monitoring, we have seen absolutely no movement of the slag stock pile,” said Hanenburg, so he doesn’t believe that a redirection of the creek is necessary.

“We have science backing us saying there is no movement,” he said, adding that the diversion of the creek at this time was not recommended.

In terms of a creek conversion, the budget estimate of $270, 000 (which was quoted in the Committee of the Whole meeting) Shepherd was greatly exceeded, as the catchment area was larger than expected with much higher velocity than was anticipated, said Shepherd.

Hanenburg suggested that the city get a hydro geology report before considering diverting the creek. The city will follow up with Pacific Abrasives and ask them to partake in the cost of hiring a hydro geologist to continue to monitor the slag pile as well as provide a hydro geology report.

“The hydro geology reports might come in and give us value, they have much stronger and better understanding of how deep down ground water flows and how it erodes over time,” added Hanenburg.