Here's how one contractor is dealing with the challenges of excavation in the tough rock underlying parts of southwestern Florida.

Ask Butch Felts about construction in his hometown of Fort Myers, Fla., and he will talk about water and rock.

These two elements shaped the construction industry in the southwestern Florida town well before Felts' grandmother started Lee Mar Building and Construction in the 1950s. Now, as owner and vice president of the earth moving company, Felts knows firsthand the challenges these two elements pose to Florida contractors.

Lee Mar is headquartered in the City of Palms, which sits on land made of bedrock layered with sand.

"The rock is hit and miss," Felts explains. "There are outcroppings of it that are very hard. It is not a solid layer across our whole county. If you move 1,000 feet to the left or right of the rock you might have sand."

Then there's the water. Of the city's total area of approximately 40 square miles, water accounts for 22 percent.

"In Southwest Florida, our natural ground elevation is 6 feet to 8 feet above sea level, and of course we have a lot of rain," says Felts. "So as soon as you dig into the ground a couple feet you are in the water table."

For decades, contractors have used explosives to create lakes for water retention and to generate fill that makes development in the area possible. But the sun and warm weather that long ago attracted Thomas Edison and Henry Ford to summer in Fort Myers also entice a steady stream of new residents to the area. The remote tracts of land where blasting once took place are now filled with new development, causing blasting to move closer to existing communities — and one result has been rumblings among area residents, who say that blasting is getting too close to their homes.

Two years ago Lee County implemented a new ordinance strictly regulating blasting, and Felts had to start looking at other options to replace blasting operations.

"Because our main work is earth moving, we needed a means to dig up the rock," Felts explains.

Now, in addition to large excavators, articulated haulers and bulldozers, the 90-unit Lee Mar equipment fleet includes a Vermeer T1255 Terrain Leveler surface excavation unit. Designed specifically for site preparation and excavation, surface mining, road construction, and soil remediation, the Terrain Leveler unit was well suited for Lee Mar's needs.

The T1255 Terrain Leveler attachment has a tilting head with top-down cutting action. With a 600-horsepower engine, the unit can dig up to 27 inches deep and 12 feet wide in one pass.

Lee Mar crews have logged 1,000 hours on the dedicated Terrain Leveler unit in the past two years, and the company is currently using it for an interchange project on Interstate 75 in Fort Myers. When an excavator failed to cut through limestone to create four water-retention lakes at the interchange, the general contractor called Lee Mar. The dense rock layer was so hard it was physically impossible to dig with an excavator, Felts explains. In addition, blasting was ruled out because of regulations and the site's proximity to traffic, a mall and residential neighborhoods.

The plans for the project called for the water retention ponds to be at least 12 feet deep. Five feet of that total depth is solid rock, which Lee Mar is removing with the Terrain Leveler unit. Felts' crew has approximately eight acres of surface to remove, or 65,000 cubic yards.

"This is a large project for the Terrain Leveler unit," he says of Lee Mar's $1-million portion of the project. The plan calls for removing 18 inches to 22 inches of rock per pass, working down to the designated depth in three passes.

Felts' crew is also removing water. Because of the required pond depth, the crew is working below the water table, Felts explains.

"Water poses the number one challenge," he says. The crew keeps the water level a foot or more below the trenching elevation by removing water with a hydraulic pump and running a ditch along the edge of the grinding level to collect additional water. After the water is pumped out, it's placed in temporary holding ponds.

But the water can actually be helpful as long as it's managed.

"Having a little bit of water on the surface doesn't necessarily hurt us because it cools the teeth," Felts says. "We just have to keep it lowered so we can see our deck."

On some jobs, it's necessary to remove as much as 10 million gallons a day, Felts states. There are also times when Florida's rainy season forces work to stop.

"We just finished a job for a hospital where we would get to cut for two days and then we would have to stop for two days to get the water down," Felts says. "The Interstate 75 job has not been so bad because they have a larger site and larger areas to retain the water."

Water and weather aside, Felts says he typically achieves good production rates. His goal is to get 70-percent utilization while his crews are running the Terrain Leveler unit.

"We are trying to get seven hours out of 10," he states.

Felts notes that the Terrain Leveler unit has not only allowed him to adapt to county restrictions and continue to effectively handle hard rock in his region, but it has also offered efficiency by creating usable fill.

In the past, Lee Mar crews would run large chunks of spoil created by blasting or a hydraulic hammer through a crusher, but Felts notes that the Terrain Leveler unit "does that all in one pass."

On the Lee Mar job site, an excavator picks up the 3-inch-minus spoil created by the Terrain Leveler unit and places it in a haul truck for use directly on the job site.

"It is a huge benefit because we don't have to crush the spoil. You don't have to handle that material three or four times to get it in a usable state," Felts says.

To get the desired spoil size, Felts says his crew removed extra teeth added for a previous job and went down to the standard pattern.

"As we got out into the limestone, the standard pattern was working fine for the size we needed," he adds.

Knowing the Florida terrain, Felts will have many opportunities to use the T1255TL. Felts' knowledge of the Fort Myers topography and soil conditions comes from working up the ranks at Lee Mar, which has 115 employees.

"I worked as a laborer and then an equipment operator," he says. "I ran practically every single type of equipment we owned in the company for several years."

This knowledge has also been passed down through the generations by his family. After owning Lee Mar for about 20 years, Felts' grandmother sold the company to Felts' father in 1971 and he is now retired.

When asked if it was a family obligation to eventually own the business and face the challenges of Florida construction, the seasoned contractor doesn't hesitate.

"It was always my hope, absolutely," he says. "And it was as expected as it could be."

By Elaine Watkins-Miller
April 2, 2007
Dixie Contractor