Holy smokes: Kennecott smelter, Utah's tallest man-made structure, to turn 35

Published: Monday, Nov. 16 2009 12:00 a.m. MST

If you were standing next to the likes of Yao Ming, Shawn Bradley or Shaquille O'Neal, you'd probably seem pretty short.

In similar fashion, Kennecott Copper's Garfield Smelter smokestack is dwarfed as it stands adjacent to the 9,000-plus-foot Oquirrh Mountains, which rise more than 4,000 feet above the Salt Lake Valley.

However, the reality is that the Kennecott smokestack is one of the loftiest, free-standing structures in the world and the tallest such thing west of the Mississippi.

Rising sharply about a dozen miles west of Salt Lake City and just south of I-80, this icon, which turns 35 this fall, is by far the tallest man-made structure in Utah at 1,215 feet.

It's almost the equivalent of having an Empire State Building high structure rising up, or equal to the height of three LDS Church Office Buildings (state's runner-up highest free-standing structure).

Built in 1974, the smokestack's hexagon-shaped base is 177 feet across.

You really don't want to stand right next to Kennecott Copper's Garfield smelter smokestack either. That's because you'll almost crack your neck, straining to look straight up and see the seemingly endless top of this mammoth structure.

A look inside its base reveals a surprising amount of open space, surrounded by concrete up to 12 feet thick.

The concrete itself towers to an even 1,200 feet, and then the fiberglass flue goes up another 15 feet.

"It's overkill for this (refinery) plant," said Jack Haymond, a consulting engineer for Kennecott who has worked there for 45 years. "But it was here. … It would cost a fortune to take it down."

He said when the federal Clean Air Act came along in 1970, Kennecott built the stack, which at the time was a good fit. It was just high enough to disperse waste gases, according to the new standards. However, with leaping advances in pollution controls, it is now taller than it needs to be.

Haymond said Kennecott, owned by Rio Tinto, is one of the two cleanest smelters in the world, capturing 99.9 percent of all the sulphur gas released.

The chimney replaced several predecessor Kennecott smokestacks, now demolished, the tallest of which was a height of 413 feet.

"They commandeered every cement truck in northern Utah" when they built it, Haymond said. Concrete flowed — more than 26,000 cubic yards — for 84 days, 24/7, minus one short break, to complete it. Some 900 tons of steel were also required.

Work on the stack began on Aug. 26, 1974, and was finished in less than three months. It is built according to Zone 3 seismic standards.

It cost $16.3 million at the time to build, the rough equivalent of almost $70 million in today's dollars.

Jana Kettering, Kennecott spokeswoman, said the stack is an icon, a landmark, for people traveling in and out of the Salt Lake Valley. She also said boaters she knows, who sail the Great Salt Lake, use it as a key geographical indicator.

Some airline pilots and frequent flyers also have been known to use it as a landmark. And it can be spotted from as far away as portions of Box Elder County, across the Great Salt Lake.

Strobe lights at two intensities — brighter in the day and not as bright at night — protect the stack from airplanes and helicopters.

What about lightning? Haymond said he's only aware of one instance when nature jolted the smokestack. He said in the mid-1980s, he came to work one day during a maintenance shutdown period and found pieces of concrete on the roadway below the stack. Lightning had chipped the top. It was soon repaired, but "no one saw the strike," he said.

Although there's a two-person cage-type elevator inside the smokestack that travels to the top, it is rarely used.

"It's a long, scary ride," Haymond said, and it takes about 20 minutes to reach the top. Today, a worker only needs to travel up to the 300-foot level each day to service an air-sampling station.

The top of the smokestack narrows to 40 feet in diameter and features 12-inch-thick concrete.

The smokestack is also part of Kennecott's efficient smelter process, which supplies about 60 percent of it owns electrical energy needs through steam generation.

A 1,765-foot-long piping system carries leftover gases into the smokestack and an interior pipe travels inside the concrete and up to the top of the stack.

Haymond said any discharge you see out of the smokestack isn't smoke, it is just steam. Only trace amounts of any waste gases escape.

According to a Wikipedia ranking of freestanding structures (those that lack guyed masts or support cables), the Kennecott Smokestack is the 31st tallest such structure (including skyscrapers) in the world. In the U.S., its is ranked fifth-highest, only behind the Willis Tower and John Hancock Center, both in Chicago; the Empire State Building in New York City; and a smokestack a mere two feet taller in Pennsylvania.

In comparison, the Las Vegas Stratosphere is 66 feet shorter at 1,149 feet high. Seattle's Space Needle is just 605 feet tall, less than half the smokestack's height.

The Kennecott smokestack, fourth tallest chimney in the world, is the only operating smelter chimney left in Utah and will turn 35 on Nov. 17. As a working facility, with many potential hazards about, public tours are not offered at the smokestack or refinery.

Kennecott's Bingham Canyon Mine, to the south, is where the copper extraction process begins, and it is the world's largest man-made excavation. Factor in this usually lesser-heralded smokestack, and Kennecott actually has two world-class man-made icons.

Smokestack facts:

Height: 1,215 feet.

Diameter: 177 feet across.

Year built: 1974

Cost: $16.3 million.

2nd highest smokestack in the U.S.

4th tallest chimney in the worldWorld's 5 tallest chimneys:

1. GRES-2 Power Station, Kazakhstan, 1,377 feet high

2. Inco Superstack, Sudbury, Ontario, Canada, 1,247 feet.

3. Homer City Generator, Pa., 1,217 feet

4. Kennecott smokestack, Magna, Utah, 1,215 feet

5. GRES, Russia, 1,214 feet

Source: Wikipedia,

e-mail: lynn@desnews.com

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