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Flying crane at Dry Fork Station

There’s no room for claustrophobia or fear of heights on this job.

Basin Electric Power Cooperative - January 18, 2010

Originally published in The Gillette News-Record
Reported by Deb Sutton

Download a PDF of the story here: Flying crane

What could have taken months of preparation and at least another month to actually finish, was over in 48 minutes Saturday morning.

The mission: Remove two hydraulic pumps, three steel beams and four hydraulic strand jacks; deliver two loads of aviation doors and five loads of rain hood sections to get the chimney at Basin Electric’s Dry Fork Station Power Plant to the 95 percent completion stage.

The workers: Three men from Midwest Helicopter Airways of Chicago, a Sikorsky S-58t helicopter and a clear Wyoming sky at 500 to 600 feet above the ground.

It was one of the last parts of the chimney project, which Kansas City, Mo.-based Pullman Power began in April.

Flying crane

Pilot Jim Triggs, 26, is in the air with 100 feet of cable hanging from the Sikorsky S-58t helicopter, which is capable of lifting 4,500 pounds. For this job, its heaviest load will be about 2,300 pounds. Altitude also puts some limits on how much can be lifted.

He explained his safety rules and laid out the parameters of the job early that morning. Should one thing be out of place, he’ll set the chopper down and stop work.

On the ground, Midwest lead mechanic John Amador, 35, is ready to grab the 15-pound hook at the end of cable and attach it to the load. He and one of the Pullman crew will work the ground.

“I’ve been up there,” Amador says. He’ll send Midwest mechanic Brian Joyner, 29, to the top of the chimney along with three Pullman workers.

“Five hundred feet isn’t bad,” says Amador, who has harnessed in at 1,000 feet for some jobs.

Pullman’s Rich Richardson, Richard Mineer and Andrew Luther help Joyner at 500 feet inside the chimney. There’s no room for claustrophobia or fear of heights on this job.

Only Amador and Joyner have direct communication with the pilot — he hears only their voices and watches only their signals.

At 9 a.m., the helicopter heads for the chimney.

“Once he gets a hold of it, we’re all at his mercy,” says Ron Harvey, Pullman project manager. “He’ll have a 4- or 5-foot hole to set this stuff down in.”

With Triggs hovering at 600 feet, the crew at the top secures the hook to a steel beam. The helicopter heads back to the drop site. At 9:04 a.m., Amador and the ground crew unhook the beam.

Triggs makes the one-half mile trip three more times, simply removing payload from the top of the stack.

“I lean out of the window” for a better point of reference. “It will let me see more or less of the stack. You’re up so high, your point of reference changes a lot,” Triggs says.

At 9:15 a.m., it’s time to start doing double duty and take loads the other way. The ground crew hooks up a load of aviation doors that will be used to access the lights required by the FAA. The crew at the top of the chimney reaches skyward to gain control of the load.

They’re working from a platform in a space about 3 feet wide.

“It’s an open roof and you can’t move around much,” Amador says.

It’s a tight fit, but not as difficult as it looks, Triggs says.

“I was feeding 150 feet of line through a 24-inch hole the other day,” he said.

It’s in the mid-40s with winds at about 18 mph and wind gusts of 28 to 29 mph. Wrestling the wind can increase the difficulty. Altitude also affects the helicopter’s power.

“There’s obviously a risk in anything you do,” Triggs said. “It’s all relative.”

Dozens of spectators at two different locations watch as the scenario continues until the final touchdown at 9:48 a.m.

Eleven trips; 16 loads totaling about 35,000 pounds. It went off without a hitch.

“I blew the line around a little on one drop, but it wasn’t too bad,” Triggs says.

“That’s what I like to see. Boring, boring, boring,” said Rich Luther, project manager from the Kansas City office, with a big grin on his face.

Job nearly done

Without the helicopter, it would have taken a month to run cable and maneuver lifts and lower each piece manually.

Those 48 minutes cost about $40,000, plus about another $40,000 in crew time and planning that took weeks to coordinate, Luther said.

“Considering the time, safety and cost, it was much more effective,” Luther said.

Dry Fork limited the bulk of its activity. Basin Electric made arrangements with Eagle Butte mine and BNSF Railway to stop all coal train traffic during a two-hour window from 8:30 to 10:30 a.m., said construction manager Douglas Ramsey. Rail Link brought in two empty train cars that allowed the mine to work while air activity at Dry Fork was going on.

National Geographic Channel had wanted to film the work for “Dangerous Jobs” but had to back out the day before. But the trio may become stars yet. DIY Network aired a segment on them for its “Project Xtreme” show. Triggs said the producer of that show is pitching an idea for a reality TV series featuring the Midwest Helicopter crew.

It’s now up to Pullman Power workers to go in and weld the rain cap in place and finish some electrical work, and the chimney will be complete, Harvey said.

Overall, the $1.35 billion 385-megawatt power plant is on schedule and under budget. Work on the plant began in October 2007 and should be complete by spring 2011, Ramsey said.

Dry Fork chimney — By the numbers

Once it’s completed and in use, the chimney will be used to exhaust the clean gas. After flue gas has passed through the Air Quality Control System — a scrubber where it is cleaned — it’s routed through the chimney.

498 feet: The height of the chimney

52 feet: Diameter of the chimney at the base, which is 21 inches thick

30 feet: Diameter of the chimney at the top, which is 9 inches thick

4,570 tons: Shell weight

120: The number of 60 foot pilings under the chimney foundation

450 feet: The distance the inside elevator will travel. After that, a ladder that runs the height of the stack must be used to reach the platform at the top.

300,000 pounds: The amount of rebar used in the shell

2,225 cubic yards: The amount of concrete used in the chimney shell

7 feet: The thickness of the chimney foundation. It includes about 1,510 cubic yards of concrete

20 feet: Diameter of the chimney liner

425 feet: The amount of carbon steel used at the bottom portion of the chimney liner

75 feet: The amount of stainless steel used for the top portion of the chimney liner

390,000 pounds: Total weight of the chimney liner

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