Rocky Road: Carving Roadways, Utility Trenches In Tough Rock

May 2013, Vol. 68 No. 5

As if the limestone weren’t challenge enough, Merck’s crews encountered several impediments along the roadway milling routes including porous limestone underground aquifers, bird habitats, flint and a variety of related “sensitive” zones. Dust control was a huge concern especially given the environmental sensitivities of the area and the very dry working conditions. “We really had to watch our dust control due to the hot and dry conditions at the time,” says Merck. “Keeping water on the trenching boom was critical.”

Working within the parameters of local, state and federal environmental guidelines was also a critical component. The entire area is situated above a huge underground aquifer with caves and openings that would need to be addressed before milling and trenching could commence. “If we came upon an aquifer, we just jumped ahead while the geotech crews came in and completed their assessment,” Merck says. “The caves and opening would need to be filled before we could proceed in order to maintain the environmental integrity of the aquifer. This often required truckload after truckload of gravel and rock. Unfortunately, we hit some massive ones.”

Trenchers on parade
Leading the parade of track trenchers was a Vermeer T1055 Commander 3 tractor with a Terrain Leveler attachment used to chart the course for the roadways; followed by a T1155, T1255 and another T1055 Commander 3 tractor with trencher attachments that were used to cut three separate trenches -- 15,000 feet total -- one for each of the wet utilities including water, storm and sanitary sewers. Strict adherence to grade was required.

“We took a couple Vermeer T1055 tractors with Terrain Leveler attachment for the intricate roadway work; mostly because of its maneuverability,” says Merck. “The terrain leveler is a very mobile machine, and has the power necessary to handle rock really well. And the Vermeer Terrain Leveler attachment is ideal for site preparation; especially in tough rock.”

Given the tough milling and drilling conditions, trencher maintenance was especially important. Merck credits the conviction of the crew with keeping the trenching attachments in tip-top shape and operator experience with knowing just how hard to push the machines. The corresponding result was production rates that exceeded expectations and projections, especially given all of the varying obstacles and impediments encountered by his crews operating the Vermeer equipment.