PLANT CITY — Concrete trucks hummed outside Trapnell Elementary School on Wednesday morning as construction crews resumed work on an underground void found last month between two campus buildings.
On the surface, there's nothing more than a slight dip in a sidewalk. But it was that dip that forced the relocation of students to two other schools while officials inspected the campus and stabilized the 90- to 120-foot subsurface void between the cafeteria and administration office.
It was one of a rash of ground depressions and sinkholes in the area reported in January, caused by heavy agricultural pumping during an extreme cold snap.
Students should be back to Trapnell within three to four weeks, said Hillsborough County Schools spokesman Steve Hegarty.
In the meantime, men in hard hats roam the school, hauling hoses and pumping tons of concrete under the fragile ground.
By Wednesday, crews had drilled dozens of hollow metal casings deep into the earth, creating an underground grid.
They use the casings to fill the grid with organic grout made of limestone and phosphate and "the same stuff that's already in the ground," explained Clay Ward, Hillsborough County Schools maintenance manager.
He said it has no adverse environmental impact.
"It's like we're recycling," Ward said. "All those rock components were here already, and we're basically just putting it back."
They're doing it little by little — pumping some concrete and then drilling down to see how much of a void is left. They've also stuck in metal posts to measure how much the earth rises as they pump.
Work began Monday but was slowed due to rough weather. By Wednesday, four concrete trucks had been emptied into the earth. Each truck holds 20 tons.
How much more concrete will be needed and how much it'll all cost is still a mystery, Hegarty said.
It'll likely be less than $1 million, with insurance covering most of it, Hegarty said. "But that's a rough, rough estimate."
But hopefully, he said, this will be the end of it.
Ward agreed, noting that they've left "no stone unturned," when inspecting the campus for more trouble spots. They've found a total of four depressions, but the other three will require only minor repairs.
"We've looked at it (the campus) from every possible angle," Ward said. "I tell you what, I would have no problem if my children or grandchildren came to school here."
Trapnell's 570 students are attending classes at the nearby Strawberry Crest High School and Bailey Elementary School.
Hegarty said the kids seem to enjoy the change in scenery, but they're ready to be back to their old classrooms, as are the teachers.
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