Snaking over highways, houses, two rock quarries and several crushers at up to 9 mph, five miles of conveyor belt is carrying 27 million cu yd of earth–and the plans of Hartsfield International, the world's busiest passenger airport–on its maximum 72-in.-wide steel and rubber back.

With the help of a unique fleet production program, 5R Constructors is working two eight-hour shifts six days a week to complete a $350-million earthwork contract for the Atlanta airport's new 9,000-ft-long fifth runway by June 2005. 5R, a joint venture of C.W. Matthews Contracting Co., APAC-Georgia and Thrasher Trucking Co., received a notice to proceed in May 2002 after a court-appointed arbitrator upheld the controversial sole bid on the project, which had been rejected by the city council (ENR 3/11/02 p. 15). The firm had the enclosed conveyor belt up and running four months later, says Q. William Hammack Jr., 5R's managing director.

CLEARING Contractor is importing 27 million cu yd of earth for new runway.

Trucks were not an option for delivering the earth directly to the site, which is enclosed by urban development, including Interstate 285 and Route 85. "It would have taken three years more to build it with dump trucks running 24/7," says Hammack. Inspired by mining practices, the team came up with the conveyor plan. "We think this is as environmentally friendly a project as can be built," he adds.

Requiring five miles worth of power cable, the belt system was supplied by local firm John D. Stevens in a subcontract. Carrying up to 7,000 tons an hour, the belt has shuttles to four discharge stations, each equipped with twin 110-ton discharge bins, hydraulics and air compressors. An initial test of the bins supplied by Aztec Industries, Chattanooga, Tenn., discharged 110 tons of earth in five seconds, causing too much impact, says Hammack. Consequently, the discharge was slowed to 10 seconds.

Four scalping plants with sieves sift out rocks more than 7-in. across. Loaders with 24-ft-wide tracks pour the earth through chutes into the sieves. The big rocks fall over the side, are placed on trucks and taken to be crushed, says Michael Thrasher, president of Thrasher Trucking. The rest goes onto the conveyor belt for a five-mile trip to the discharge bins.

The earth must adhere to a 5% moisture standard, says Hammack. Two portable crushers and two regular ones keep rock available to mix with earth for winter construction.

The contractor also is using 26,000 8.5-ft x 12-ft slabs 15-in.-thick from a runway rehabilitation job as subgrade for the new runway's average 90-ft fill. The team now is moving earth for the first 6,000 ft of runway, with the other 3,000 ft located on the other side of I-285. It will be linked by a 1,100-ft-wide runway bridge that 5R lost to Archer Western Contractors, Atlanta, in a contested design-build award for $159 million (ENR 1/13 p. 14). The 3,000-ft section will be ready by August, says Hammack.

TRACKED Equipment is monitored remotely.

The team partnered with Caterpillar Inc. and its Atlanta-based dealer Yancey Bros. Co. CAT is the exclusive equipment provider, 5R just fuels and greases the machines and Yancey does the rest of the maintenance under a $1 million contract. But the partners also will share savings achieved from the high-tech fleet, based on historical averages."There is no other job where CAT has this sort of agreement," says Yancey vice president Bud Wilfore.

The fleet of 100 machines includes 15 D-9R and D-8R dozers, three 5110B excavators, six wheel loaders, six compactors and model 777D haul trucks. A Website-based GPS system shows a real-time map of the site and where each machine is. It also sends diagnostic updates on machine condition–everything from fuel level to oil pressure to overheating–and alerts headquarters within eight minutes if an operator is abusing the equipment, says Carl Sponsel, Yancey airport project manager.

Benjamin DeCosta, general manager of Hartsfield, says there will be $250 billion in long-term benefits from the total $1.2-billion runway and related projects for the $5.4-billion expansion. 5R could receive $10 million for early completion, but could be penalized $20,000 in liquidated damages if it is delayed past June 2005.

(Photos courtesy of 5R Constructors)