The state is stabilizing a slope at the Pali Tunnel where more than 10 tons of mud and debris slid onto the highway in 2006, closing it for days before the area was cleared and deemed safe.

The $700,000 Pali Slope Stabilization Project began July 13 and is expected to last until October, said Tammy Mori, state Department of Transportation spokeswoman.

Crews will be removing loose rock and dirt, as well as clearing and grubbing the top four inches of the slope on the Honolulu side of the town-bound tunnel portal, Mori said in an e-mail.

Work also includes installing an anchor mat system that will cover about 16,800 square feet. The geotextile matting will be anchored four feet into the ground, she said.

It's a state-of-the-art high velocity erosion control system that is being used all over the country, Mori said.

Finally the slope will be hydromulched, a process in which grass seeds are sprayed onto the mat to add to the erosion control.

"There will be times when the right lane (town-bound) will be closed in the project area," Mori said. "However, this week, only the shoulder lane is affected."