“Monster” Project Heads Towards Finish Line

As work progresses on the new Holcim cement plant in Ste. Genevieve County, MO, one fact stands out: the job is immense. Successfully completing such a big job takes more than big construction equipment; it takes ingenuity, determination, and grit.

“I will probably never see anything like it again in my career,” Will Chipley, project director for MC Industrial, said of the mammoth industrial project. “It is an absolute monster,” agreed David Payne, president of PayneCrest Electric. “It is just so enormous it is breathtaking,” he said.

Once complete, Holcim's Ste. Genevieve plant will be the largest single-kiln cement factory in the world, capable of producing 12,000 metric tons of clinker per day and 4 million metric tons of cement a year. The production line stretches for over a mile from the limestone quarry and ending at a harbor on the banks of the Mississippi. In between, a system of conveyors carries limestone to the raw meal silos, the mill, the kiln, the clinker cooler, clinker silos, the finish mill, and cement silos. The total facility uses 1,700 acres of a 3,900-acre site.

The general contractor is a joint venture of the Washington Group and Alberici called WGA. Site development began in 2005; construction of the facility began in 2006, and WGA is scheduled to turn the facility over to Holcim in December 2009.

Bloomsdale Excavating, the designer-builder of the site, began excavating in August 2005. Their first order of business was the harbor. Bloomsdale was responsible for digging and dredging the harbor, building an earthen dam to hold materials from the harbor construction, excavating and developing 70-acres for the plant to sit on, building the quarry development roads, and building an access road to the plant site. By the time Bloomsdale Excavating finished site work in July 2006, they had moved an estimated 7 million cubic yards of rock and earth. To clear the plant site, they had to drill through as much as 125 feet of limestone and blast as much as 60,000 yards at a time.

Award-Winning Silos

A joint venture of MC Industrial (MCI), a McCarthy company, and T.E. Ibberson Co., came on site next as the design-build contractor for 13 silos concrete silos: two, 275-foot tall raw meal silos; two, 207-foot tall clinker silos and one off-spec silo; eight, 275-foot tall cement silos. Later on, two more 155-foot tall cement silos at the harbor were added to their contract. MCI also won a contract to build a limestone reclaim tunnel and the material handling conveyors from the clinker silos to the cement mills.

MCI self-performed 99 percent of the work on the silos, Chipley said. “It was the largest self-performed labor project McCarthy ever performed,” he said. Constructing the material handling equipment between clinker silos and the cement mills, in which MCI self-performed 65 percent of the work, was probably second largest self-perform labor project McCarthy ever performed, he said.

MCI built the silo walls with a process called slipforming, by which the tubular shape of a silo can be seamlessly cast in continuous process that uses a short section of formwork that moves upward with the pouring process. The form essentially rises into the air on the back of the concrete just cast. Computer-controlled hydraulic jacks raised the form one inch at a time on jack rods, at nearly nine inches an hour, said Chipley. “The rate is determined by how fast ironworkers can install the rebar,” he said. The jack rods consisted of 10-foot lengths of three-inch pipe. Workers would insert a new section of rod as the form reached the end of the previous section.

“Slipforming is quite a challenge because once you get started you can’t change anything,” Chipley said. MCI worked two, 12-hour shifts when forming each silo. When forming the first two silos, two crews of 85 trades people worked continuously for 16 consecutive days to slip the 275-foot tall structures. Another 83 people worked in support positions on the site. Most of the crew consisted of ironworkers, who installed 2 million pounds of rebar in 16 days while riding the forms. Three thousand, three hundred cubic yards of concrete went into each of the two silos.

“You get ten weeks to set up the form and you better have every single thing you need: every piece of equipment and every tool, and back-up equipment in case anything breaks down. A lot planning goes into it, and if you do not have a good plan, your chances of success are slim to none,” Chipley said. “Once you start a slip, you can’t stop. Luckily, we had a partner who does these all over the world,” he said.

MCI took 18 months to build 13 silos, and only 72 days were actually consumed with slipforming. The two clinker and one off spec silos were formed in 14 days using 8,000 cubic yards of concrete and 3 million pounds of rebar. Each clinker silo is 150-feet in diameter and the form for it weighed close to a million pounds, Chipley said. “It is half the length of a football field and it is basically jacking itself up to 210 feet in the air on little 3-inch pipes,” he said.

The eight concrete silos, slipped as two “four packs” shaped almost like four-leaf clovers, were the biggest challenge. “It was hellish,” Chipley said. “It was in June, but the daytime temperatures went into the 90s,” he said. With the sun beating down and heat coming off the concrete, the temperatures on the form were even worse. Chipley couldn’t stop the slip once it started, so he had to plan for extra breaks, and extra workers to give breaks or replace anyone who might get sick from the heat. The planning paid off. Each four pack took 16 days to form, and used over 20,000 cubic yards of concrete, 5.6 million pounds of rebar, and 400 miles of post-tension cable. “We had about 500 workers on the forms and probably another 150 working on the ground. With all the overtime, our weekly payroll approached $3 million,” Chipley said.

In completing the first 13 silos, MCI workers logged more than 700,000 hours and placed 66,000 cubic yards of concrete and 20.5 million pounds of rebar. 

Slipforming, although intense and impressive, was just the beginning. Post-tensioning the silos took even longer – post-tensioning the cement silos took three months, Chipley said. Conduit for the post-tensioning cable was installed during forming. Later, a kind of “gun” shoots the cable through the conduit. It took a special kind of ironworker to work on the post-tensioning at night. “They worked off of galleys hanging from the tops of the silos, and these would sway as the wind whistled by. Of course we lit the job up at night, but when you look down at the lights, everything behind them is black,” Chipley said. Not everyone is comfortable working on a hanging platform swinging over a seemingly endless void. “I know I couldn’t do it,” Chipley said.

MCI also had to install cone-shaped domes inside each cement silo as part of the system for distributing cement. Each dome is made up of 24 pie-shaped pieces of precast concrete, weighing 65,000 pounds each. The pieces are designed to be locked together with rebar and a strip of poured concrete over the rebar at each joint. As with any dome, however, the problem is how to support the individual pieces until the whole is completed and the various parts support each other. MCI used a single 2-inch cable attached to a turnbuckle to hold each piece in position at the proper 60-degree angle until it could be locked to its neighbors. “We lowered them into position by crane, but the crane operator was working blind, because he was outside the silo,” Chipley said. “It was hard to get the 4-point rigging system right to get the 60-degree angle,” he added.

Post-tensioning preceded construction of the dome-shaped bin bottoms, which preceded the installation of the roof, which preceded the installation of conveyors. MCI will finally finish the cement silos almost two years after forming them.

The silos are probably the most stunning part of the Holcim project and MCI already has won four awards for building them.

Big Electrical Job

Holcim also is the largest project ever for PayneCrest Electric. “It is positively the biggest self-perform job we’ve ever done,” said PayneCrest President David Payne. “We have 400 electricians there. We are responsible for all of the electrical work from the incoming power feeds – which are 345,000 volts, which is highly unusual – lighting, all of the power feeds to all of the substation electric rooms, and wiring all of the motors and all of the control devices,” he said. PayneCrest is performing the job for a fee with a time and materials contract.

“A lot of the work is very unique. The machinery comes from several different companies. Some of it is 450 feet in the air, some of it is out over the harbor,” Payne said. He said the Holcim project accounted for about half of the company’s revenues in 2008.

Like PayneCrest Electric, Coatings Unlimited is working along almost the entire length of the project. “We’re painting everything structural from the primary crusher all the way to the harbor,” said Steve Phillip, Jr., project manager for Coatings Unlimited.

The painting is mostly touch-up work – most of the structural steel comes with an anti-corrosion zinc coating applied at the factory and Coatings Unlimited is painting the seams, welds and bolts where pieces were joined together in the field. Phillip said 90 percent of the job consists of applying anti-corrosion zinc coatings from St. Louis-based Carboline Co. The other 10 percent consists of epoxy coatings for handrails or concrete floor coatings.

Even as mainly a touch-up job, it is a large project. When the weather is good, “we have 56 men and six company trucks on site,” Phillip said. He estimated that the job would run to 100,000 hours before it was done.

The painting work at Holcim involves a lot of high work. “We’re using Spider baskets and 134-foot tall lifts,” Phillip said. The toughest part was the 500-foot tall preheat tower, said site superintendent Billy Myers. “We had to climb around on that like ironworkers,” he said.

Although less than halfway through their job, Coatings Unlimited has already won a Finishing Touch Award for their work on Holcim from the Painting & Decorating Foundation.

PayneCrest and Coatings Unlimited are subcontractors to WGA.

“This is one of the neatest projects going on in the country,” Phillip said. “Holcim and WGA have been excellent to work with.”

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