Boring in Downtown Las Vegas
Doing any kind of road work in downtown Las Vegas is going to take some planning, but installing 4,500 feet of fiber-optic cable in the middle of the city is going to require weeks of painstaking coordination.
This was the case for Brian Dunlevy and his crew at Team Fishel in Las Vegas. The company was hired by AT&T to reinforce an existing fiber line, which will upgrade a new long-haul fiber communications line and make a dark-fiber integration between AT&T and Level 3 Communications, which operates one of the largest communications and Internet backbones in the world. Dark fibers are lines that have yet to be used within cables that have been already laid and are not yet connected to any device. They are there for future usage.
Team Fishel, based in Columbus, OH, is a family-owned utility construction and network installation contractor with 23 offices in 11 states. The company was founded by Ken Fishel back in 1936 and moved into the Las Vegas market in 2006 after purchasing Kaccel Communication, a longtime underground contractor in the area.
Before starting on the downtown project, Team Fishel completed a 7,500-foot install in Warm Springs, NV, just west of Interstate 15. The 4,500 feet in downtown Las Vegas continued the project and was just north of the Strip, running along Las Vegas Boulevard to Charleston.
"The planning was pretty substantial on this project," said Dunlevy, area manager for the Las Vegas Division of Team Fishel. "We had to coordinate with the city and county, as well as the Nevada Department of Transportation."
In addition to the fiber line upgrade, a 7,000-foot road improvement project was taking place at the same time. Team Fishel had to work with other contractors to coordinate schedules. The entire permit process took about 3-1/2 weeks.
Planning and Preparation
The project began in September 2007 and required 12,000 feet of drilling for the installation of 70,000 feet of cable, as well as cable marker posts and five manholes.
"It was a pretty substantial project from that perspective," Dunlevy said.
It wasn't just the pre-planning that took time. Onsite preparation was also tedious. Team Fishel went in and researched each drill shot, exposing the existing facility as they were marked to discover the depth and distance on the running line. Information about existing facilities was entered into the Vermeer Atlas Bore Planner software, which provides a graphic visualization of the job.
Using the data that is entered, Atlas Bore Planner provides a path to follow — or tells the operator what to move to make the bore work. The bore path is provided in two formats: one screen displays a top and side view, the other shows a report that lists the depth and pitch of each drill stem.
"Southwest Gas required a 24-inch separation from any transmission line and 12 inches from all distribution lines," Dunlevy says. "We could plug in all the existing facility information and let the Atlas Bore Planner plan all the depth and distance from the existing lines."
Once the planning was completed, Team Fishel turned to its Vermeer D36x50 Series II Navigator horizontal directional drill to install three 1.5-inch HDPE conduit lines to hold the new fiber-optic cable for AT&T.
Drilling Through Caliche
One thing that can be a real problem in the Las Vegas area is caliche — a calcium carbonate that was formed when water running through the valley built up layered deposits and sealed itself off so that water could no longer run through. It's very difficult to drill through, and operators don't like to run into it.
"The drill head we used gave us the capability to drill through hard soil and cut and carve the caliche," Dunlevy said. "That way we could make our steering corrections. We had to get 22 feet deep to get under a transmission line and provide proper clearance."
At one point the crew got into an underground wash area, where they switched to a standard 5-inch duckbill to complete a couple of shots in soft, sandy gravel. This drill head gave Team Fishel the flexibility to make the steering corrections required in the soft soils.
"We ran into a substantial amount of caliche in the downtown portion, and we were able to get through it successfully with the Vermeer drill," Dunlevy recalled. Caliche in the Vegas area can range from 6,000 to 12,000 psi and can force crews to change plans midstream.
"The caliche prevented us from getting down to grade," Dunlevy continued. "With the angle of inflection required to be successful, we had to maintain a defined pitch and depth, and the caliche wouldn't allow us to drill through it. So we excavated about a 10-foot-long area approximately 18 inches wide and busted out the caliche with a hoe ram."
Dunlevy added that this excavation was the launch pit that allowed the team to get below an 18-inch-thick layer of caliche about 24 inches below the surface.
Dunlevy needed a 5.5-inch tunnel for the conduit. Once the pilot bore was completed, the crew used a 6-inch fluted rock reamer to build the tunnel and pull back the three 1.5-inch HDPE conduits. Once that was accomplished, they made their tie-in at each bore location. Standard EZ-Mud Bentonite mixtures were used for the job, except when the drill hit the wash area and needed some additives to maintain the bore tunnel. The length of the shots on this job averaged about 450 feet, Dunlevy said, with some as long as 550 feet and others as short as 250 feet.
A Leader in Directional Drilling
Team Fishel has used competitive drill rigs in the past, Dunlevy says, and decided to go with Vermeer.
"We were one of the first companies to really endorse the whole mini-directional drill program in the mid 1980s," he said, adding that the directional drilling market in LasVegas "is trailing" in comparison to other parts of the country.
"We need to make sure everyone understands the cost savings to the customer and the convenience to the traveling public," Dunlevy added. "Our use of directional drilling is one of the things that make Team Fishel the best choice for our customers."
This project was the first of a three-phase project for AT&T, coming in at $570,000 for Team Fishel's work. Dunlevy estimated the project would take about 20 days of boring, and it took 19 days with up to 18 teammates on the job at one point.
"There's more work coming to extend this line," Dunlevy says, "but that's still in the future." AT&T is a long-time customer for Team Fishel, who also does work for Verizon Business, Nevada Power, Level 3, Cox Communications, and Time-Warner Telecom.
Dunlevy has advice for those working in an area where caliche might be found.
"Just avoid it if possible!" he said with a laugh. "Most of the caliche layers are just that — in layers. Knowing where the layers are is going to determine your success. Once you get into them, maintaining proper grade and pitch is probably not an option. You usually have to excavate through the layer to get under the layer and get back out."
He added that caliche is very abrasive with cemented gravels, feldspar and quartz in it, which makes it very different from the soils and ground conditions usually found in some areas.
"The drill operator will know when he hits it immediately," Dunlevy explained. "You can't carve, you can't push — being able to carve through caliche just isn't feasible or time-effective."
The biggest challenges Team Fishel faced on this job involved coordination with the various city, county and state entities.
"Safety is always a huge concern, and we needed to make sure we had a strong safety plan in place for our teammates, customers and public," Dunlevy said. "In addition, we needed to accommodate traffic and pedestrians." By working nights, Team Fishel kept inconvenience to motorists and pedestrians to a minimum.
|Valerie Van Kooten is a technical writer for Two Rivers Marketing, Des Moines, IA. Story and photos courtesy of Vermeer Corp., Pella, IA.|