How the stacks will fall: Dynamite part of $8.8M effort to bring down Asarco icons

by Chris Roberts / El Paso Times

How the stacks will fall

When the two tallest Asarco stacks are demolished within seconds of each other early next year, old-time dynamite will bring them down.

The stacks — one of which rises 826 feet and displays the Asarco lettering — will be among the last vestiges of a smelting plant that operated for more than a century. Soon after the stacks fall, workers will turn their attention to isolating and cleaning contaminated soil and groundwater. Ultimately, the intent is to sell the property for other uses — both commercial and residential.

There is historical symmetry in the use of dynamite, which will be employed to fell the concrete stacks like giant tree trunks. At the turn of the century, when the plant was built, dynamite was replacing nitroglycerine as a safer tool for mining raw materials processed by the smelters. Over time, the plant’s furnaces purified copper, lead and other materials blasted from the Earth’s crust.

“It’s (dynamite) still the best workhorse in the industry,” said Jim Redyke, president of Dykon, the explosive demolition company hired to bring the stacks down. Redyke’s Tulsa, Okla.-based company has used explosives to bring down numerous structures in Texas, including Texas Stadium, and around the world, including a 900-foot smokestack in South Africa, which the company bills as the world’s “tallest stack shot.”

“I’ve done hundreds of smokestacks,” Redyke said in an interview last week at the Asarco site.

Also among those were two “little brick stacks,” one that fell as a car drove under it in the Burt Reynolds movie “Hooper.”

“I call that being paid to play,” he said with a smile.

Redyke would not discuss the price, but Roberto Puga, the trustee in charge of the $52 million demolition and cleanup, said it falls within the site’s $8.8 million demolition budget.

The method Redyke will use to bring down the Asarco stacks — the other is about 600 feet tall — is almost exactly like felling a tree, but in reverse, he said.

Hammers are used to chisel out a channel parallel to the ground on the side opposite the direction he wants the stack to fall. That channel provides access to vertical steel rods, called rebar, embedded to strengthen the concrete. Those rods are cut with torches, which will allow the stack to tip over quickly. When the time has come to knock the stack down, explosive charges on the other side are detonated, blowing out a section that begins the fall. Concrete hinges — part of the stack wall on either side of the blown-out section held together by uncut rebar — direct the stack to its intended drop zone.

“Gravity is my friend,” Redyke said.

Unlike a tree, with uneven branches and twists and bends in the trunk, the stacks stand straight and most of the variables are known. Nonetheless, core samples will provide information on the concrete’s strength. The 900-foot stack in Africa unexpectedly collapsed on itself, which Redyke attributed to poor concrete. The cores and other tests will tell him how much concrete to leave for the hinges.

“The real issue would be the direction of the fall,” Redyke said. “You could get directional failures.”

Nonetheless, Redyke said his methods have produced consistent results.

His website shows four 500-foot stacks dropping neatly in a line, one after another. “There was five seconds between each of those,” he said.

When the Asarco stacks fall — despite the fact that the larger stack contains approximately 860 average cement mixer loads of concrete — noise and vibration will be minimal, Redyke said.

“It isn’t comparable to anything nature can produce,” Puga said.

Although there will be nothing like an earthquake or thunder clap, there will be localized vibration, a pressure wave and dust.

Efforts will be made to protect two historic Asarco buildings — the administrative building and the power house, which are not being demolished. That involves protecting original lead-glass windows from flying debris and taking steps to bolster century-old brick facades, said Jeffery L. Bauguss, a partner with Environmental Resources Management, a Houston company running the site demolition.

Another potential problem is instability in the built-up slag on the sides of the plant, Puga said. An inspection will determine whether reinforcement is necessary, he added.

When the stacks do fall, Bauguss said, it’s possible they will guide them into exposed basements of buildings already demolished to hold dust and debris.

It’s like a “catcher’s mitt,” Redyke said.

A canopy of mist will be used to trap the dust, Puga said. With contaminants such as lead, arsenic and cadmium present in the soil, he said, the goal is to have the dust “dissipate within the limits of the site.”

“It will be a custom application,” Puga said. “We’ll be bringing in designers.”

Water also will be sprayed on the ground to stabilize the dust just before the stacks are dropped.

“That doesn’t take much water,” Puga said. “We don’t want to make mud, just dampen it.”

The design also will allow capture of the water, which likely will contain contaminants, in stormwater ponds on the site, he said.

And monitors already placed around the site’s perimeter will be used to detect fugitive emissions, he said. Results from those dust monitors are posted monthly on the cleanup website, and so far the only spikes detected have been attributed to windy days and railroad maintenance, Bauguss said.

After the stacks are on the ground, it will take a month or more to crush the concrete, Bauguss said. The steel rebar will be salvaged.

“There will not be anymore (dust and noise) than what we’ve had for the last three months,” Puga said. “And we will continue with our air monitoring.”

No detailed plan is on paper, however, and Puga and the contractors will be soliciting input, including a public meeting scheduled for Nov. 3, Puga said. Meetings with city officials and their counterparts in Juárez started last week.

“We’re taking this nice and slow to give everybody a chance to be involved,” Bauguss said.

Likely the biggest disruption will be the temporary closure of Interstate 10 and Paisano Drive.

“It will be for as short a time as possible on a (weekend) morning,” Puga said.

Puga and the others are aware of the intense community interest, which could lead to another problem.

Anyone sneaking on site to get a better look is not only putting themselves in danger, but could end up delaying a delicate and costly process, Redyke said.

“There’s always somebody who wants to get a closer view,” he said.

Chris Roberts may be reached at; 546-6136.

More about the demolition

  • A public meeting on the demolition is scheduled from 5 to 7 p.m. Nov. 3 at El Paso’s Downtown Main Library, 501. N. Oregon.
  • The meeting will include a multimedia presentation explaining the process, and experts will be on hand to answer questions.
  • Site officials said they will propose a plan to preserve about the bottom 10 feet of the tallest smokestack “as a memorial to the workers and what happened here.” Artists could use copper left after smelting operations ceased to create commemorative plaques.