Mosaic Fertilizer will ask county commissioners today to approve the biggest change to its mining boundaries in southeast Hillsborough County since 1995.
The phosphate company wants to add about 1,500 acres to their approximately 25 square miles at the Four Corners mine east of Wimauma. It won't be able to dig there yet, but the county's approval would put Mosaic one step closer to getting a permit to mine on seven new parcels.
Not everyone likes the idea. Tampa Bay Water and some nearby residents want more regulations on Mosaic's mining operations before their boundaries are expanded.
Tampa Bay Water wants the company to agree to test for heavy metals at its new mining sites — especially one that that's planned near a creek that leads into the Alafia River, a regional drinking water source.
Hillsborough phosphate and land officers have already approved Mosaic's request without requiring additional testing. The final decision rests with county commissioners, who will decide if Mosaic can add the land to the master plan.
Neighbors say they don't like the noise or dust from mining operations at the Four Corners mine. They also say they're concerned with the water table levels and animal habitats.
"We can't enjoy our property," said Norma Killebrew, who lives near Mosaic's mines along State Road 674. "I can write my name on anything in my house, even when it's closed up, because the dust filters through."
This time, the opposition isn't just residents. Tampa Bay Water experts wants Mosaic to test for heavy metals at its mining sites, especially the 80-acre parcel near Hurrah Creek, which drains into the south fork of the Alafia River.
Mosaic tests for about a dozen compounds there now, including fluoride and chloride. That's required by the state's Department of Environmental Protection and Hillsborough County.. But Tampa Bay Water wants Mosaic to also test for about a dozen metals, including arsenic, lead, iron and aluminum, said Paula Dye, the chief environmental planner for Tampa Bay Water.
Mosaic officials say they aren't concerned that those metals could enter the water at the Four Corners mine because Tampa Bay Water has been testing for them for about a year at the nearby Hopewell mine. No problems have been noted there, said Mosaic spokeswoman Diana Youmans.
Still, Tampa Bay Water contends that contaminants could be released at Four Corners when thousands of tons of dirt are disturbed by mining. And increased testing for metals is crucial because the Alafia River is now a drinking water source, Dye said.
Another concern is that Hurrah Creek is highly acidic, said Terry Thomas, a Tampa Bay Water hydrogeologist. That means any metals that leak into the water would dissolve quickly and couldn't be contained, he said.
But Mosaic officials insist there's no worry about metals leaking into the water because there's no problem at the Hopewell mine, which uses the same processes and water management system as the Four Corners mine, Youmans said.
Tampa Bay Water officials will continue to push for the additional testing as Mosaic applies for a permit to mine the 80 acres near Hurrah Creek.
"Our goal is to make sure the environment and public health are protected," Dye said.
Jessica Vander Velde can be reached at firstname.lastname@example.org or (813) 661-2443.