Crews begin repairing, filling Mosaic sinkhole

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A sinkhole at the Mosaic plant in New Wales, that sent 215 million gallons of "slightly radioactive" water into the Florida Aquifer last year, is being sealed shut 

After about five months, and lots of backlash, workers at the Mosaic mining plant in Mulberry are filling the 150-foot wide hole that infuriated hundreds of residents because no one told them about the spill until after the groundwater was polluted.

An investigation by the Florida Department of Environmental Protection began on August 29, and is still ongoing. DEP has also done regular testing of nearby water wells, but all of the test results in the world may not convince Louella Phillips Whitford her water is completely safe.

"I don't even give my dogs this," she said of the well-water at her home, 3.7 miles from where the hole opened in September.

RELATED: Mosaic pond leaks 215M gallons of 'slightly radioactive' water

At the time, neither the company nor the DEP told residents because state law said they only had to report a spill if they were aware it spread beyond the boundary of the business' property.

"Am I feeling better? No, they are just sealing up what they have already dumped in, if you ask me," Whitford said.

Mosaic conducted measurements of the massive sinkhole in mid-October using a LiDAR radar unit - technology that uses light in the form of a pulsed laser to provide three-dimensional mapping. Crews used that mapping information to determine where to position drilling equipment to begin the process of filling the hole with a sealant. 

The LiDAR mapping from October showed the visible cavity of the sinkhole is around 220 feet deep, and 152 feet in diameter at its widest, according to Herschel Morris of Mosaic.

RELATED: Mosaic offers glimpse inside sinkhole -- sort of

Mosaic says crews will work 24 hours a day for six days to fill the hole with 23,000 cubic yards of material. They will first line it with a tougher grout material, so it will be almost like filling a drum.

"Whatever they put back in," said USF geologist Philip van Beynen, "none of that is going to be able to go back out."

Van Beynen says he is confident that a proper job will prevent that particular sinkhole from opening back up. He also says the groundwater is likely to have diluted the pollutants by this point.

"Even if it does migrate, the levels of the contaminants and the radioactivity, which people talk a lot about, the radioactivity wasn't very high in the water in the first place."

RELATED: Neighbors worry water isn't safe after Mosaic leak

Last week, the DEP said it had tested 1,250 nearby water wells and that all were acceptable, showing no signs of sinkhole-related pollution. They are also keeping an eye on an additional 82, which have unusual results. But - DEP says - those results are likely unrelated to the sinkhole.

For Phillips Whitword, a closed sinkhole doesn't mean it's forgiven or forgotten. She will remain afraid of the water coming into her own home.

"I can't even raise my kids here, I can't bring my kids here, my grandkids. I can't let them drink the water when they are here," she said.

RELATED: Class action lawsuit filed against Mosaic for sinkhole

Mosaic has been ordered to do four rounds of testing this year, which started this week. Results for that should be completed in another month.

The sinkhole repairs are expected to cost up to $50-million and take five to six months to complete.