ILIAMNA, Alaska _ A brown bear loped across rolling green tundra as Charles Weimer set down a light, single-engine helicopter on a remote hilltop.
Spooked, the big grizzly vanished into alder thickets above a valley braided with creeks and falls. Weimer's blue eyes scanned warily for more bears. He warned his passenger, Mike Heatwole, to sit tight as the blades spun to a halt, ruffling red, purple and yellow alpine flowers.
The two men, each slim with a goatee, stepped out into the enveloping silence of southwest Alaska's wilderness. Before them stretched two of the wildest river systems left in the United States. Beneath their feet lay the world's biggest known untapped deposit of copper and gold.
Weimer and Heatwole worked for Pebble Limited Partnership, a subsidiary of a Canadian company that aims to dig Pebble Mine, an open pit the size of 460 football fields and deeper than One World Trade Center is tall. To proponents, it's a glittering prize that could yield sales of more than $1 billion a year in an initial two decades of mining.
It could also, critics fear, bring about the destruction of one of the world's great fisheries.
Six weeks after that June 24 visit, Weimer, 31, would die when reportedly taking a single-engine plane through aggressive maneuvers in mountains near Anchorage. One of three other people killed in the fiery crash was the plane's owner, Karl Erickson, who had directed Pebble's safety operations and investigated aviation accidents.
The deaths of two members of the "Pebble family," as company spokesman Heatwole termed it, were a reminder that technology is fallible and that best-laid plans can go awry.
The Pebble Mine site lies 200 miles southwest of Anchorage. One hundred miles farther southwest is Bristol Bay, home to the world's largest run of wild sockeye salmon. Early each summer, hundreds of 32-foot commercial fishing boats surge into the bay, charging into state-designated territories like riders in the Oklahoma Land Rush. The fishery generates 14,000 jobs and $1.5 billion a year.
Captains and crews come from around the world to reel in as many tons of sockeye as they can during the lucrative two-month season. Regional tribal leader Robin Samuelsen Jr. worked the bay last summer for his 54th season, his four grandsons reeling in wildly wriggling fish.
"We have a gold mine," he said. "It's in salmon."
Alaska has long been known for grand ventures and great risks. It's also known for the richness of its natural resources, including gold, copper _ and salmon.
In the case of the Pebble Mine, the question is: Can they coexist?
Geologists discovered and named the Pebble deposit 20 years ago. The resemblance that they fancied to California's famed Pebble Beach golf links understates the wild beauty of the place, where rushing streams feed shimmering lakes in valleys of mossy tundra. Pebble Partnership's corporate parent, Northern Dynasty Minerals, originally envisioned 78 years of mining, which would recover a little more than half of the mother lode.
In hopes of getting the initial phase past the U.S. Army Corps of Engineers for permitting under the Clean Water Act, the company scaled down its project to a 20-year mine that would still be colossal, with waste piles and other facilities occupying a site more than half the size of Manhattan.
Northern Dynasty's plan leaves little margin for error.
The development would destroy more than 3,400 acres of wetlands and 81 miles of streams. It would straddle Upper Talarik Creek and the Koktuli River, Bristol Bay tributaries known nationally for trophy trout fishing and salmon spawning.
Mineralized rock would be blasted in the pit, crushed, ground into sand, floated and concentrated, producing 180,000 tons of material a day. The challenge facing the company, in a place that averages more than 50 inches of rain a year, is how to ensure that tainted water would never reach Bristol Bay, which contains more than half the North Pacific's sockeye salmon.
Northern Dynasty would submerge particularly hazardous mine tailings, piled across more than 1,000 acres, in water to prevent acid generation. This waste would be contained in liners behind earthen dams and ultimately dumped back into Pebble's open pit after mining ended.
Less hazardous bulk tailings, heaped across 2,800 acres, would be held back by massive embankments designed to channel seepage into a treatment system. In all, these tailings dams, some as high as 40 stories, would extend more than 10 miles.
Company representatives say the bulk waste would have the consistency of inert sand. They say their latest plan would move most operations out of Upper Talarik Creek to reduce risks. But mine opponents say subterranean water systems are interconnected, and federal scientists say the latest groundwater models are inadequate.
The company plans to prevent contamination by treating as much as 13,000 gallons of discharge a minute on average from ore processing, tailings seepage and pit drainage, funneling it into the Koktuli River. The amount, which dwarfs quantities handled by other U.S. hard-rock mines, would increase to 22,000 gallons of water a minute after the mine closed. It would level out at 5,000 gallons a minute thereafter _ perpetually, every day of the year, through storms, power outages and earthquakes.
In Bristol Bay, commercial, sport and subsistence fishermen worry about the dams, fearing they could breach or water treatment could fail. If so, contaminants in Upper Talarik Creek could spew into Iliamna Lake, Alaska's biggest, and from there down the Kvichak River into the bay. Or toxins could enter the north and south forks of the Koktuli, flowing into the bay through two more rivers also legendary for salmon spawning.
And that isn't the only concern.
Northern Dynasty proposes a 188-mile natural-gas pipeline across Cook Inlet to supply a power plant that could light up a city the size of Gary, Ind. An icebreaking ferry would carry ore 18 miles across Iliamna Lake, connecting to a haul road built through bear migration territory, and from there to a proposed seaport.
Ringed by snowcapped mountains, 80-mile-long Iliamna Lake is so pure that it needs no filtration for drinking. Its shores are dotted by half a dozen Alaska Native villages accessible only by boat or plane. The lake is home to sockeye and king salmon, and rainbow trout more than 28 inches long.
Environmentalists worry that the ferry and industrial activity could harm a rare species of freshwater seal inhabiting the lake. Village residents say the ferry would sever the thick ice they depend on as a winter roadway.
