If you’re building a new plant, Paul Blatner’s the guy you want working on it.
“This is the 78th I’ve been involved in,” says maintenance operations director of Prairie Material’s updated facility in Des Plaines, Ill. “They all have a story, but this is the most efficient plant I’ve built with the least potential for congestion.”
Yard 8 opened in early August 2017. Designed and fabricated by Erie Strayer Co. of Erie, Pa., the facility features two identical central mixers and a dry mix lane with 16 overhead aggregate storage compartments and 10 cement compartments. It’s one of Erie Strayer’s biggest and, according to Sales Manager Kyle Strayer, fastest. “Top capacity with both central mixers running a 60-second mix time would be about 700 yards per hour."
“The first day we produced 1,000 yards,” Blatner says. “Our busiest day was 2,500 yards.” The old plant could produce as much, but it was archaic and unreliable and would have taken more than 12 hours. “Now we put out 2,500 yards with no problems at all in a little over eight hours.”
Strategically located next to O'Hare International Airport and less than a mile from two interstate highways that provide easy access to Illinois, Indiana, and Michigan, Yard 8 is Prairie's top metropolitan Chicago plant. It’s been integral to the $6 billion O'Hare Modernization Program and Illinois Tollway Authority expansion projects.
"It started as a single dry batch plant, and in the early 1990s we added an Erie Strayer central mixer," says Blatner, who oversaw the renovation. "But after more than 40 years it had grown tired. The only choice was to rebuild.”
Once the decision was made, non-essential components were removed while production continued through 2016’s construction season. The plant was completely shut down by December and disassembly began in earnest. "We salvaged what we could to rebuild and carefully disposed of everything else," says North American Ready-Mix Maintenance Operations Manager Matt Clarage. "All scrap steel was recycled. The central mix plant, a portable plant that we had built a building around, was taken down and stored for future use."
Balancing environmental and productivity goals
The plant may be next to one of the world’s busiest airports, but it’s also near wetlands. To respect surrounding habitat and comply with existing environmental permits, Prairie had to keep the same footprint for both the plant and aggregate piles, some more than a quarter-mile away. Wetland considerations ruled out moving them closer and airport restrictions limited plant height to 85 feet.
"Site limitations made for some interesting design/build choices," says Erie Strayer Service Manager Joe Bogda. "We had to redesign the angles for some conveyors based on the regulations." Logistical roadblocks seemed to constantly arise, says Blatner, but “we complied with everything and still got the plant we wanted.”
Prairie rebuilt the underground aggregate conveyor lines and added an exterior back-up conveyor with a side hopper to ensure continuous material flow. “The conveyor is an elaborate underground system,” “The original intention was to fill the tunnels, but I argued there was no way to replicate their magnitude—and eventually I won. They thought I was nuts. We had to reverse the direction of one conveyor and fine tune all the gate timing, but it works perfectly.”
Engineered for safety, efficiency and comfort
Even though it occupies the same physical footprint, Blatner and his team took the opportunity to reconfigure traffic patterns and locations of critical services to work more efficiently and ensure everyone's safety. Blatner’s driven ready-mix and bulker trucks and spent time as a trade mechanic, and this experience is reflected in the traffic flow through the plant.
Empty mixers enter on the property’s west side, out of the way of loaded mixers on their way to the washdown area. The two activities are separated by a maintenance shed, which effectively creates two one-way routes. "We tried to minimize backing up and blind corners," says Blatner. "The lanes are straightforward with no obstacles and the path makes sense. Everyone knows where to go.”
Bulkers also come in on the west side, where drivers check in at the scale and are directed to the appropriate blow line for uploading products. Each line is identified with a number.
The batching office was custom-built by a local fabricator using a metal cargo container that sits atop salvaged I-beams that face the plant. It has windows on all sides and sliding windows on the ends so the operator can talk to drivers. “The dispatcher never has to worry that he put the wrong load in a truck,” says Blatner. “They don’t have to strain or look at a camera; they can see the trucks and the plant and the truck being loaded.
"It's quiet and air-conditioned, with large tinted windows that provide good sightlines. Spray foam insulation underside makes it quieter and more environmentally sound and keeps the floor from getting cold during the winter so the plant operator doesn’t have cold toes. It’s heaven for the those guys."
Quality control is located just north of the old ground-level office, protected by concrete block bollards and next to the washdown area. The office was renovated with a new driver area featuring modern bathrooms and a small lunch area. "Sixty-five people work here every day," says Blatner. "We wanted to provide comfort for the team and efficiency for the business."
Flexible capabilities for any job
The plant holds up to 10 cement types and 16 aggregates. Airport work routinely calls for binary slag/cement mixes that incorporate a specially graded airport stone. Warehouse floors often require a blend of cement mixes with two to three graded coarse aggregates to prevent curling.
The tollway’s increasingly complex requirements for high-performance pavement mixes, bridge decks, and rapid repairs sometimes require three or four cementitious materials including fly ash, slag, and, at times, silica fume. "Combinations of coarse aggregate blends and addition of lightweight fines for internal curing are also common," says Prairie Technical Services Representative Gary Hall.
The plant easily accommodates specialty cements like the white cement used for the exterior of the airport’s new car rental facility. The setup also permits use of aesthetic specialty aggregates like pea gravel and red flint directly through the plant.
Water is stored in two buried 15,000-gallon rail tanker cars with a keep-full system. “We didn’t want to be at the mercy of the city,” says Blatner. “This way, even if there’s an interruption in supply, we know we have 30,000 gallons to keep operating.” When weather changes, the water can be run through heaters up to 100° F or chillers down to 44° F.
The new plant can handle all of these requirements on any given day with a combined overhead storage capacity of 920 tons of cement and 1,080 tons of aggregates. The two central mixers ensure consistency for larger jobs and a guaranteed backup during maintenance.
A team effort
More than 40 Prairie employees contributed to disassembly and rebuilding. “We lived with this for a year,” Blatner says with obvious satisfaction. “Sweated over every nut and bolt. I often had to argue for one feature or another, but in the end we got everything we wanted and made this a plant that’s a pleasure to work at.”
To celebrate the reopening, Prairie hosted an onsite breakfast prepared by the Prairie cooker crew for employees, contractors and Erie Strayer’s team. "We all had a stake in the project, right from the beginning," says Blatner. "Everybody's very proud of it.
Prairie Material is a Votorantim Cimentos company.