The two-lane country road rambles through rural Manatee County, abruptly veering to the right at a ranch fence. Beyond the fence lies a broad pasture, flat as a plank, where rust-colored cattle loll in the shade of the occasional oak. Far from the highway a modest stream trickles southward, its flow fed by ditches dug 50 years ago.

The biggest phosphate mining company in the world, IMC-Agrico, wants to turn this quiet farmland just south of the Hillsborough County line into a strip mine, digging deep holes and building mighty hills around them, all in the name of making fertilizer.

But that tiny stream is giving the phosphate giant a mammoth headache.

This particular dribble happens to be the headwaters of the western fork of Horse Creek, a remarkably pristine waterway that feeds the Peace River, which eventually rolls into Charlotte Harbor, the state’s most productive estuary.

IMC’s critics say mining for phosphate on that 2,400-acre spread would damage the creek, and thus harm the river, ultimately sending an environmental disaster rippling down into the harbor more than 30 miles to the south.

The state Department of Environmental Protection is ready to give IMC a green light. But the potential downstream impact has brought together an unprecedented alliance of local governments, environmental groups and a major water utility to force a legal showdown with IMC on July 10.

Concerned about the harbor’s billion-dollar industries of fishing, tourism and recreation, the Charlotte County Commission is challenging the DEP permit.

“We want to protect the harbor,” said Bill Byle, Charlotte County’s natural resources planner, who has campaigned tirelessly to stop this mine. “We don’t believe you can strip mine . . . the headwaters of the most productive estuary in the state without affecting the quality, quantity and timing of freshwater flows into the estuary.”

Thanks to Byle’s lobbying, Charlotte was joined this month by the Lee County Commission, Sarasota County Commission and Peace River- Manasota Regional Water Supply Authority, which uses the river to supply drinking water to 100,000 people.

The water authority’s attorneys contend that IMC’s mining “will reduce the amount of available water in the Peace River, thereby curtailing the amount of potable water that the authority can supply to its customers.”

The list of mining opponents also includes three environmental groups: ManaSota-88, DeSoto Citizens Against Pollution and the Environmental Confederation of Southwest Florida. They’re concerned about the effect on water quality, as well as the destruction of habitat for egrets, herons, bears, frogs and snakes.

IMC has never before been challenged by people so far away. Spokeswoman Diana Youmans said, “I don’t know of another challenge we’ve had to permits before from downstream.”

Because Horse Creek flows 36 miles from the mining site before it joins the Peace River, and the Peace flows another 12 miles before spilling into Charlotte Harbor, the company contends the opponents have no legal standing to challenge the project.

Besides, IMC officials say, they have the expertise to protect the creek, river and harbor. Their plan: divert the creek while mining the streambed, then put it back minus the ditches.

“It’s a ditched pasture,” Youmans said. “We’re not asking to mine a pristine area of Horse Creek.”

“I think that’s just outrageous,” said Alan Behrens of DeSoto Citizens Against Pollution, who lives on the creek. Despite IMC’s promises, he said, once a place is mined “nothing is the same.”

IMC’s opponents might seem to have picked an odd place to draw a line in the sand.

The ranch land that IMC wants to mine is known as the Manson Jenkins property. It lies just off Duette Road a few miles south of where Manatee, Hillsborough, Polk and Hardee counties meet and where IMC’s Four Corners Mine already operates. The Manson Jenkins mine is small compared with the gigantic mines of nearby Polk County, and the draglines would operate for less than a decade.

But this is just the opening salvo in a battle over the future of the billion-dollar phosphate industry.

IMC-Agrico now supplies one-fifth of the world’s phosphate, with customers as far away as China and Australia.

The legacy of the mineral-rich oceans that covered Florida in prehistoric times, phosphate is a key ingredient in fertilizer.

But after decades of mining, the ore in Polk County is nearly depleted. IMC needs to open new mines, and soon. The company wants to open a mine on 24,000 acres at Pine Level in De Soto County and another on 23,000 acres near the Hardee County community of Ona, which together should produce phosphate for another 20 to 40 years.

IMC hopes to begin mining at Ona as early as mid 2002, Youmans said, while the Pine Level project is further down the road, as are some smaller mines planned near the Four Corners Mine. Meanwhile another phosphate company, Farmland-Hydro LP, wants to begin mining 14,400 acres near Ona, too.

All three of those big mines and one of the small Four Corners additions are close to Horse Creek, so Charlotte officials are opposed to all of them. The Manson Jenkins mine was the first one to get DEP approval so it was the first one they challenged.

“If we don’t go to battle over this one,” Byle said, “we may have lost the right to challenge future permits.”

IMC officials are quick to point out that the Peace River watershed has been the scene of phosphate mining for a century. But they concede that Florida’s long drought has sharpened concerns about the impact that mining has on the water supply.

And despite the company’s promises of environmental sensitivity, IMC bears the stigma of past disasters.

In 1994, a settling pond at an IMC-Agrico mine in Hillsborough burst, spilling 500-million gallons of slimy, gray water toward the Alafia River, flooding homes, killing livestock, mucking up ponds and contaminating private wells.

State officials blame phosphate mining, along with agriculture and other land uses, for poor water quality in the upper reaches of the Peace River. The water authority plant draws drinking supplies from the Peace just south of where Horse Creek flows into the river.

Horse Creek’s water is so good that one water official observed that the Peace River’s purity is “barely acceptable for water supply purposes . . . until the waters of Horse Creek enter it.”

Behrens and Tom Reese, a St. Petersburg environmental lawyer, have been lobbying the DEP for years to add Horse Creek to the list of Outstanding Florida Waters to protect its purity. DEP officials have resisted granting the protection because of objections from IMC.

To Reese, IMC’s plan to divert the creek and then rebuild it makes no sense. It’s so good the way it is now, he said, “you couldn’t re- create it.”

To mine Manson Jenkins, IMC plans to destroy or disturb 361 acres of streambed, bay swamp, gum swamp, freshwater marsh, wet prairie and shrub marsh, plus 1,988 acres of uplands on the property.

But what Byle finds more disturbing is what the company will leave behind when it is done: clay settling ponds that he says are “less permeable than concrete” and thus will block the flow of groundwater into the creek, lessening the amount flowing into the river and harbor.

If all the mines near Horse Creek are approved, Byle said, they are sure to cut the flow of water into the river and harbor. (IMC says what cuts the flow are the new wetlands they create when they reclaim the land after mining.)

Byle said Charlotte officials spent four days searching DEP files “and we couldn’t find one shred of evidence they had looked at any of the secondary or cumulative impacts for the Manson Jenkins mine or any other mine.”

The U.S. Army Corps of Engineers has turned down a request for a regionwide study of the impact of mining, but even agencies that have taken no position for or against IMC are pushing for someone to undertake such a review before more mines are allowed.

Last week board members of the Southwest Florida Water Management District were discussing the impending showdown over Manson Jenkins. Someone suggested paying IMC for its mineral rights as a way of blocking the new mine and protecting Horse Creek.

No thanks, Youmans said. “Phosphate production is our core business,” she explained. “I don’t anticipate that we would be wanting to sell our reserves.”