The puddle-deep stream known as Halls Branch trickles through the shadows of sand pines and water oaks near the rural Hillsborough County community of Welcome. As it meanders to a rendezvous with the Alafia River, its quiet burbling is easily drowned out by the urgent “beep-beep-beep” of earthmovers pushing dirt around an old mine nearby.

But what happened to quiet Halls Branch, which was itself mined nearly 20 years ago, has echoed so loudly that it could affect the future of Florida’s billion-dollar phosphate industry.

After miners finished digging phosphate out of Halls Branch it was supposed to be restored. However, experts from the state Department of Environmental Protection who tested Halls Branch and nine more streams found only one to be healthy. Most, including Halls Branch, had poor water quality.

Now the world’s largest phosphate company, IMC Global, wants to mine the headwaters of the west fork of Horse Creek, one of the cleanest streams in the state. IMC officials promise they will restore the creek when they are done, but IMC’s opponents cite the DEP studies of Halls Branch and the other streams as a reason to turn the company down.

“Their program of restoring mined streams is not working,” said Tampa attorney Ed de la Parte, who represents Charlotte County in challenging IMC’s mining plans, a challenge that broadened last week. “The studies of what’s been done so far show that they can’t put it back the way it was.”

Until DEP officials find a better way to clean up after the miners, he said, “they shouldn’t be allowing phosphate companies to mine these streams.”

IMC officials contend they do a fine job of putting streams back the way they were, but it takes time.

“There are some impressive reclamation projects,” said company spokeswoman Diana Youmans, explaining that restored streams “have to mature.”

Charlotte officials say they can’t wait a generation or two for a clean Horse Creek because of what that means downstream. Horse Creek flows into the Peace River, which supplies drinking water for 100,000 people, and ultimately gushes into the state’s most productive estuary, Charlotte Harbor, itself the center of a billion-dollar tourism and recreation industry.

For decades the center of Florida’s phosphate industry has been in Polk County, and the leader has been IMC. IMC supplies one-fifth of the world’s phosphate, the legacy of the mineral-rich oceans that covered Florida in prehistoric times.

Now the Polk mines are winding down, their resources depleted. The industry’s future lies to the south, in Manatee, DeSoto and Hardee counties, closer to Horse Creek and the Peace River.

IMC officials hope to open a mine on 24,000 acres in Pine Level in DeSoto County and another on 23,000 acres near Ona in Hardee County, which together should produce phosphate for 40 years.

But first, IMC has asked DEP for a permit to mine a 2,400-acre pasture known as the Manson-Jenkins Tract in the headwaters of Horse Creek in Manatee County, just south of the Hillsborough line. IMC has also requested a mining permit for the 2,390-acre Altman Tract, which is also in Horse Creek’s headwaters in Manatee. Both would become part of the Four Corners Mine, already the biggest in country.

DEP approved the Manson-Jenkins permit, sparking a legal challenge from a rare coalition: Charlotte, Sarasota and Lee counties, the Peace River-Manasota Water Supply Authority and three environment groups. A lengthy trial this summer centered on the downstream impacts. A judge has yet to rule in the case.

In the meantime, although the DEP has not yet approved the permit for the Altman Tract, the state agency last month approved a new reclamation plan for that area that includes the Altman Tract. Last week the Charlotte County Commission, which has already spent $1- million battling IMC, voted to challenge that project, too.

As IMC tries to move into the future, it has had to deal repeatedly with questions about the industry’s past damage to the environment, such as the 1994 accident that sent 500-million gallons of slimy, gray water rolling toward the Alafia River, flooding homes, killing livestock, mucking up ponds and contaminating private wells.

The industry’s answer to questions about its commitment to the environment has been to point to its record of reclaiming land after the mining is done. Last year IMC reclaimed 3,400 acres, 200 more than it mined, and its projects have won awards from the National Wildlife Federation and other organizations.

In the case of Manson-Jenkins, IMC officials point out the pasture was ditched to drain it. When IMC is done mining, the company will build wetlands instead.

Although miners have been digging phosphate out of Florida’s streams for more than a century, reclamation is a recent phenomenon. Until 1975, most miners left behind a desolate moonscape. Then the state began requiring miners to reclaim their pitted land, but it has taken a while to figure out what that meant.

The miners “have gotten a whole lot better over the years” at reclaiming land, said Janet Llewellyn, deputy director of DEP’s water resources division. “And we’ve gotten smarter about what to require.”

Yet scientific studies by University of South Florida professor Henry Mushinsky have challenged the industry’s contention that the finished product successfully mimics nature. Mushinsky compared the wildlife on upland forests and marshes that had not been mined with the wildlife on forests and marshes that had been mined and then reclaimed.

“We were looking at amphibians, birds, reptiles, mammals,” Mushinsky said. “We found species that were underrepresented – they were not as common on the mined sites as on the unmined sites.”

Mushinsky’s studies have proven controversial.

“The industry didn’t like what we found,” he said.

The industry sees the study’s flaws, according to Bob Kinsey, director of operations support for IMC. Some of the sites Mushinsky studied were reclaimed before the 1975 law, and were not designed to attract wildlife, he said.

Of greater concern to Charlotte County were studies done by the DEP itself on Halls Branch and other reclaimed streams. They formed a crucial part of Charlotte’s legal case against IMC’s permit.

Longtime Welcome resident J.O. Chestnut remembers running cattle along Halls Branch years ago. He recalls seeing turkey and deer along the banks.

That was before IMC came along in the early 1980s and mined about 4 acres in and around the stream, then moved along to the land next door. Reclamation of the stream began in 1984. Work crews filled in the pits, then planted grass, trees and underbrush.

Then, in 1999, DEP officials came back to check Halls Branch, along with nine other streams that had been mined and reclaimed in Hillsborough, Polk and Hardee counties. They compared them with a stream that had never been mined: Horse Creek.

Only one of the 10 stacked up as healthy: Dogleg Branch, a tributary of the Alafia that had been reclaimed in 1983, making it the oldest one studied. The rest all flunked DEP’s tests because they had low flow rates, poor wildlife habitat, smothering by silt and clay and even water quality violations.

“These scores suggest that, overall, restoration activities at the study streams have not provided for full habitat recovery,” the DEP study found.

Halls Creek in particular had an unusual problem: ammonia. DEP researchers found it had “a higher concentration than is found in 90 percent of Florida streams.”

Hillsborough County officials say the high levels of ammonia come from phosphate mining in the area. But IMC’s expert, Doug Durbin of Biological Research Associates, says the ammonia came from leaves and other organic material that has fallen into the water and decomposed.

The trouble with the DEP studies, said Durbin, is that DEP focused on small streams that had not been given enough time to fully recover. IMC can plant trees and dig channels, he said, but “you have to wait for nature itself.”

Llewellyn of the DEP agreed. The nine streams that did not get a passing grade “are progressing. It’s just that they’re young.”

But Charlotte’s environmental expert, St. Petersburg biologist Tony Janicki, pointed out that the mining itself takes a decade or more. If reclamation requires another 20 years before Horse Creek is fully recovered, “that’s a long time for being disturbed. Yet DEP considers mining a temporary disturbance.”