Crews from Gateway Grading and Development, Lenoir, NC, worked around-the-clock for one month in an effort to reopen heavily-traveled U.S. 321, which had been closed because of an early April mudslide.

The rock and soil flowed like water down the mountain late evening on April 9, taking more than a dozen large trees and a small portion of the highway with it, according to Jody Kuhne, a North Carolina Department of Transportation (NCDOT) geologist.

No injuries or damage to private property were reported.

Unlike some mudslides that just cover a road with muck and block traffic, this washed away part of the heavily traveled road as well as dirt, earth and other materials underpinning the asphalt.

NCDOT officials detected the landslide on April 10, and promptly closed a 300-ft (91.4 m) section of the road. They called in Gateway to rebuild the hill and the road. Approximately 9,300 cars travel the section daily.

Chris Barlowe, Gateway president, quickly mobilized his crews.

“We got the call on the 11th, and we started work on clearing and building an access road. The road had just washed down the mountain. From top to bottom, the slide was about 200 feet long and steep and about 800 feet across,” said Barlowe.

“The first few days our crews were just clearing and making an access road so we could start excavating. It took us 11 days to get the bottom cleared out and a haul road set up. We started hauling shot rock out of the quarry on the 12th day,” said Barlowe.

Because of fears that rain, which caused the mudslide in the first place, would further hamper the project, Barlowe decided to pave the access road as well as the switchbacks they were cutting into the steep slope.

“We decided early on to put asphalt binder material on the haul road. The grades were so steep that they would have been shut down by the rain. Paving the access roads enabled us to work day and night throughout the rain,” explained Barlowe.

“Normally, we don’t pave the access road, but this was a busy highway. There was so much pressure to get this road up and going. There was a lot of steep terrain. It was 200 feet straight down. A lot of switchbacks had to be dug out and paved. Here we were working on a mudslide, but we had to bring dirt in — 10,000 yards of fill dirt to help with the paving so the project would stay on track,” Barlowe added.

His crews, which worked two 12-hour shifts for the entire 30-plus days of the project used a Hitachi 300LD excavator, a Hitachi 220LC excavator and a Cat D6H dozer, a Volvo 25C articulated dump truck and an 84-in. (213.3 cm) padfoot vibratory roller

The machines were only on one shift — all the time.

“We never shut machines off. Our mechanic was on site 24/7 as well. He did maintenance on the machines while they were running and while the shifts were changing. We never shut them down,” said Barlowe.

“Cat and Hitachi, they were both fabulous. We had a lot of excessive wear damage on the buckets because of the heavy rock, but that was to be expected,” he added.

The crew, headed up by Donnie McGee, superintendent, included Dennis Brinkley, Dwain Church, Joe Sutton, Nathan Beaver, Kevin Ritch, David Gilbert, Rocky Townsend, and Frazier Stallings.

Originally, NCDOT had planned to rebuild the slope by stacking rock-filled wire cages — each one 9 ft. (2.7 m) long by 3 ft. (.9 m) wide and deep — in 25-ft. (7.6 m) tall steps up the embankment, forming a retaining wall to keep the slope stable, according to Kipp Turner, an NCDOT engineer.

But as the project started to move forward, Kuhne determined that the soil of the roadbed was stable enough to support a slope of 3-ft. (.9 m) wide rocks mixed with fine rock dust. She said the rock and dust mixture would hold together better than ordinary soil and, most importantly, wouldn’t absorb water as easily, reducing the risk of another slide.

Barlowe recruited two different quarries, Vulcan Materials and 321 North Stone Company, to speed up production of shot rock. The quarries were six and 18 mi., respectively, away from the site.

“We had to build the whole slope back up with shot rock. Both quarries worked 24/7 just like us. We transported two large drills for Vulcan so they could boost production. They kept the rock coming,” said Barlowe.

Crews used Kenworths and Macks to ship 78,100 tons (70,900 t) of class one rip rap boulders 4 ft. (1.2 m) in diameter.

Gateway replaced the fill dirt that once formed the slope with 35,000 tons (31,600 t) of the rock and dust mixture. Then, they shored up the embankment with approximately 20,000 more tons (18,100 t) of the mixture, installed permanent signs and a guardrail and applied Geo-grid material to stabilize the ABC stone.

“In some spots, we had to rebuild the road. It was a two-lane federal highway. In some spots a four lane. The slide had washed out the road completely, right down to the bedrock,” said Barlowe.“We had responded to previous slides for DOT. We are probably the largest contractor in the region. When the road was closed, it basically shut down one town and severely hampered another. There was a lot of pressure to get it opened up.”

The road was opened on May 10, a full three weeks ahead of schedule, Barlowe mentioned proudly.

“There was no performance bonus. We just did what we normally do. We had a lot of help. The quarries worked around the clock. DOT took care of traffic for us and cut through a lot of red tape,” Barlowe said.