PAGE – The moment Page, surrounding Navajo communities and NGS had been waiting for arrived.
Ron Gilbert, vice president of operations for Dykon Blasting, sounded the three-minute warning horn at 8:30 a.m. on Friday.
“I-X, clear?” he yelled to the crew with Independence Excavating, the NGS decommissioning program manager.
“I-X Clear!” came the reply.
“Here we go!” Gilbert shouted. “Five, four, three, two, one … fire in the hole! Light it up, Lem!”
With that, Lemuel Brown, NGS site services manager, who was given the distinction of setting off the charge, drew a breath and pressed dual triggers in the small yellow case sitting on a pickup tailgate. That sent a remote, timed signal to NGS’ three 775-foot stacks and the huge Unit 3 electrostatic precipitator.
Five seconds later came the immense report of the first blast from the Unit 1 stack, then the second, then repeated blasts from the precip, and finally the Unit 3 stack.
The pressure wave that followed the boom was strong enough for all to feel 2,000 feet away, just beyond the Black Mesa-Lake Powell railroad loop. Cell phones and cameras shook in hands.
The Units 1 and 2 stacks fell exactly where they were supposed to, like ponderosa pines. So did the Unit 3 stack, but not without hesitating several seconds.
From a close-up video, it appears the pressure wave from the precip blast caused a horizontal crack near the base of the Unit 3 stack. That caused the stack to “telescope,” or drop down into its base, and pause for a few seconds before also falling where planned.
“Once you press that button, you have no control,” Gilbert said. “From then on, it’s up to the glory of God, gravity, concrete and rebar.”
In fact, the planning, execution and teamwork of the NGS stacks demolition was flawless. The excitement was palpable. Emotions stirred.
“The nerves and the feelings and the jitters inside were just tremendous,” Brown said. “To see those things come down like that, I’m still shaking. A lot of adrenaline’s going. I feel a little bit emotional. It’s not something I would have thought just watching it fall. It’s unreal.”
SRP Director of Special Projects Gary Barras, who is overseeing every step of the NGS decommissioning, said he was also awed.
“In my many years as a civil engineer, I have never witnessed such a powerful, historical and epic event as the felling of Navajo Generating Station’s three 775-foot stacks,” he said. “In just 54 seconds, the three monumental giants toppled, the earth trembled and the skylines visible from spectacular Lake Powell, Antelope and Glen canyons changed forever.”
Like hundreds of people who worked at NGS for decades, Bob Roessel, executive principal in SRP Intergovernmental Relations, had a special relationship not only with the plant but with these three stacks in particular.
In the mid-1990s, he was one of the NGS Scrubber Project’s managers responsible for contracts and construction. He watched the stacks rise from a deep bed of concrete to replace the three original NGS stacks. The Scrubber Project removed 95% of sulfur dioxide from NGS emissions.
“I think about all the work we did back then,” Roessel said. “It’s just amazing, the effort.”
Besides the design, engineering and construction expertise needed to build the stacks and scrubbers, Roessel is especially proud of SRP’s commitment to provide opportunities to Navajo workers.
“We developed a craft training program that helped apprentices get to the journeyman level,” he said. “When contractors showed up, we actually had qualified Navajos ready to work.”
The Navajo welders learned to weld with finesse the corrosion-resistant C-276 nickel-molybdenum-chromium alloy that lined the stacks and scrubber vessels, something welders from elsewhere couldn’t do.
In recent weeks, workers with program manager Tetra Tech, decommissioning general contractor Independence Excavating and explosives subcontractor Dykon Blasting drilled holes where dynamite would be packed into the base of each stack. Steel I-beams were wedged into the stack windows and vent openings to prevent each one from twisting in an unintended manner and to help them fall in the planned location.
“More than 300 holes were drilled near ground level on the northern 18-inch-thick inside walls on each of these stacks,” Barras said. “The vertical reinforcing steel within the concrete was sawcut along the southern quadrants at the bases of these 70-foot diameter structures.”
Explosives were fixed to support beams of the 199-foot-high steel-frame Unit 3 precip, which was built in the early 1970s and was original to NGS. With an electric charge, the precipitators captured fly ash so it would not be emitted into the atmosphere. For years, it was recycled as a valuable component in cement to cause it to flow easier and set up harder.
Today, work continues on decommissioning the plant and eventually restoring the NGS lease area back to as close as it once was, said Brown, the Site Services Manager. Like many NGS employees, he grew up in Kaibeto on the Navajo Nation, 31 miles from the plant, and saw it rise from the desert floor. He’s worked there for 36 years.
“It’ll never be exactly the same, but we’re going to try our best to make it look like nothing was ever here,” he said. “We’ve got a few more blasts that we’ve got to do with the precips, boilers and power block. It’s a lot of work. We’ve still got a long way to go.”