Mosaic’s Sinkhole Problem Is A Lot Worse
New drone video has been released showing just how big the sinkhole at Mosaic’s New Wales mine in Mulberry really is.
Mosaic, the world’s largest phosphate company, used a cage full of electronics that included a LiDAR radar unit, which uses light in the form of a pulse laser, to provide three-dimensional mapping of the sinkhole.
It is 152 feet across at its widest point, and 220 feet deep – making it one of the deepest sinkholes in the state. In fact, the deepest sinkhole ever measured by the Florida Geological Survey went down 250 feet, according to Florida Department of Environmental Protection records.
So far Mosaic officials say testing has found no indication that the 215 million gallons of contaminated water that poured down the hole in August have spread through the aquifer to taint drinking water of neighbors. State scientists say radioactive water from the mine has reached the Florida Aquifer, but based on the monitoring of wells nearby, they believe it has been contained on the Mosaic property.
Three wells have turned up with somewhat elevated levels of pollutants, but those pollutants found did not match anything from Mosaic.
Herschel Morris, Vice President of Operations at Mosaic, said the company hopes to seal the hole before May 2017.
When the sinkhole first opened up officials believed its depth varied from 300 to 700 feet, so it’s not as deep as they had once feared. There is no pond water on the bottom, said Morris, but the gyp stack debris cluttering the bottom is porous enough to let water pass by it.
Morris said the goal of collecting a map of the sinkhole was to find a safe spot from which to shoot concrete into, then fill it up the rest of the way with gypsum, ultimately sealing it up.
Now that the shape of the sinkhole has been established, Morris said they hope to begin working on it in December. Mosaic expects the repairs to cost up to $50 million.
Background On The Sinkhole
The sinkhole opened up on August 27th at Mosaic’s Mulberry plant. While it allowed contaminated water to flow into the aquifer, neither Mosaic nor the Department of Environmental Protection notified neighbors or the general public for three weeks.
State law does not require public notification until the pollution shows up outside the boundaries of a landowner’s property, but Governor Rick Scott is trying to change that. Initially Scott defended the DEP for staying silent, then announced his disagreement with the law and his plans to change it. The DEP was told by Scott to begin requiring any company or government agency that has a pollution spill to report the incident to the public within 24 hours, using the media.
Equipment Used To Map The Sinkhole
There was a combination of cutting-edge technology and home-grown construction savvy used by Mosaic to put together a map of the v-shaped sinkhole.
Their survey was conducted with LiDAR, which stands for “light detection range.” By illuminating a target with a laser it measure the distance to that target. Kind of like the way sonar sound works.
Sanchez Brothers Custom Fabrication, a Ruskin company that normally makes T-tops, was also brought on for this survey to encase the LiDAR in a protective cage that could be lowers into the sinkhole. The company designed the cage to house the device and keep it safe.
Inside the cage was also gyroscopes to keep the LiDAR level, and seven cameras to keep an eye on what the LiDAR device encountered. Mosaic officials also flew a drone over the hole while the cage was being lowered down, to make sure it was positioned properly, said Morris.
Another Mosaic Sinkhole?
Over the weekend Mosaic experienced a second such spill. This time the spill came at its Plant City facility and involved 50,000 gallons of phosphoric acid.
Mosaic officials say they contained the spill and it did not spread, so there is no threat to neighbors this time.