Midwest Rockfall put temporary protection systems in place to try and contain the loose stone.
Ryan Fetzer, president of Midwest Rockfall, feels like he aged 10 years in a month — courtesy of what was supposed to be a fairly typical, small-scale project.
Midwest Rockfall was awarded an $800,000 rockfall mitigation project on Colorado’s Interstate 70, between Empire Junction and Georgetown. The scope of the project initially included installing five different fences, plus some slope netting, to prevent rocks from rolling down a particular chute of Georgetown Hill and landing on the highway. It was projected to be an eight- or nine-person job and was scheduled to last about four months.
Rockfall mitigation projects are common in the area. Since 2006, the Colorado Department of Transportation has spent between $8 and $9 million on Georgetown Hill mitigation projects. With more than 40 chutes to channel rocks toward the interstate, Fetzer said that Georgetown Hill is “one of the most-looked-at hills in the country” in terms of stabilization methods.
The chute that Midwest Rockfall began working on this January begins 1,500 ft. (457.2 m) above the highway; much of the work is done with helicopters. On the lower slopes, crews are using a crane purchased last year from Stevenson Crane Service of Bolingbrook, Illinois: a Manitou MRT telehandler, with a reach capacity of 67.6 ft. (20.6 m)
“We also have a man basket we can put on it; we have forks for it; it will take a bucket and [we can] move a limited amount of dirt with it, though it’s not made for digging. It’s a real handy machine,” Fetzer said.
Approximately two weeks into the project, things got complicated.
It came to CDOT’s attention that a rock nest approximately 350 ft. (106.6 m) up Georgetown Hill could be more of a risk than initially estimated, due to the pace at which the dirt base under the boulders was eroding.
So, a series of engineers re-examined the site and made recommendations.
“It wasn’t like it was discovered, ’Oh my God, this is horrible.’ It got more serious as time went on,” said Fetzer.
CDOT’s Web site explained: “The boulders have a high potential of coming loose and down to I-70. Engineers will not know how long it will take to remove all the boulders until the depth of the cluster can be fully examined.”
“CDOT’s engineers and outside consultants decided collectively that the rocks needed to come down immediately,” said Fetzer. “So we dropped everything we were doing on the rest of the contract and it was all hands on deck to get systems in place to remove the rocks that were 350 feet up the hill.”
Removing the rocks meant closing down I-70 in an area that serves 30,000 motorists daily. Commerce was affected; local ski resorts, in particular, were far from thrilled with the shutdown. In addition, because I-70 is a major trucking route, the state had to advertise the closure as far away as Georgia, according to Fetzer.
The project’s ramifications continued to escalate: Midwest Rockfall received calls from the state governor’s office and from the media; NPR covered the rockfall mitigation project, as did Denver-area media. Concerned citizens were also following the project closely. Residents who lived across the interstate “swore up and down they could see this whole pile of stuff [the rock nest] moving,” said Fetzer.
Much of the attention was focused on the possibility that the boulders being removed would roll across the interstate, down another slope, and damage Georgetown homes. So, in addition to the standard netting used in such projects, Midwest Rockfall put in place a temporary protection system that utilized 30-yd. dumpsters stacked together “like Legos,” as Fetzer put it, to build a make-shift berm. A row of shipping containers on the far side of the interstate formed another protective barrier.
The day that Midwest Rockfall crews were scheduled to move the rocks down the hill, hundreds of people gathered to watch; Georgetown schoolchildren were freed from their classes for the occasion.
The Georgetown Hill portion of I-70 was closed for eight hours during rock scaling, as crews inflated special airbags that filled until the rocks broke free of the slope.
Other equipment used on the project included Caterpillar 320 and 330 excavators and a Caterpillar 966 loader, all rented from Wagner Equipment Co. Because out-of-state projects make up 75 percent of Midwest Rockfall’s business, renting is more efficient than hauling equipment thousands of miles to the job site.
“It doesn’t make a lot of sense for us to buy stuff like standard loaders, dozers, excavators. Most of what we own is pretty specialized to the rockfall industry,” said Fetzer.
With the high-profile rock scaling and interstate closure out of the way, Midwest Rockfall can wrap up the rest of the contract by installing rockfall attenuator fences to act as a permanent catchment system.
Given the unexpected complications of what has mushroomed into a $1.5-million project, it was unreasonable to expect crews to finish by the original date of May 26. Instead, Midwest Rockfall has agreed to finish all work requiring traffic control by that date; other tasks will continue into July.
Although Fetzer says that April was the toughest month Midwest Rockfall has ever had, “We got through fine, everybody’s happy.
“And I’m a little older because of it.” CEG