The history books have it all wrong. For Napa County, the Gold Rush wasn’t in 1849. It happened less than 30 years ago in a remote corner of the county ruled by jackrabbits.

From 1985 to 2002, Homestake Mining Co. extracted $1 billion worth of gold from the desolate landscape above Lake Berryessa. For a time, the McLaughlin Mine was the biggest producer in California and one of the largest in the world.

Fired by visions of wealth, prospectors roamed this rocky terrain in the mid-19th century. They found mercury and some silver, but the gold was hidden from view.

There were no nuggets or glittery veins. This gold existed in microscopic and submicroscopic particles. Without Homestake’s sleuthing and modern extraction technologies, the billion-dollar Napa Mother Lode wouldn’t have happened.

Until Homestake’s gold strike, Napa County had produced less than 25,000 ounces since pioneer times. The McLaughlin Mine would do a lot better.

Homestake blasted two open pits, burrowing

900 feet beneath the ghost pines and chaparral. One of the pits swallowed the old Manhattan quicksilver mine, which had extracted cinnabar for more than a half century.

Huge trucks removed

150 million tons of rock, 38 million tons of which contained gold. This valuable ore was crushed to a powder, piped five miles as slurry, then baked and bathed in a sodium cyanide solution.

By the time the processing plant closed, 3.4 million ounces of pure brilliance had been extracted.

The McLaughlin Mine touched portions of Napa, Lake and Yolo counties, with most of the gold coming from Napa. What became of it?

To find out, a reporter and a photographer loaded up with sandwiches and bottled water and set out on a two-hour trek into a landscape that grew ever wilder.

Civilization petered out after Pope and Berryessa valleys. On the final stretch, Berryessa-Knoxville Road dipped into dry stream beds before shrinking to virtually one lane. Cell phones ceased to work.

At the McLaughlin Mine, there were few traces of history to be seen. The processing plant that had operated 24 hours a day, 365 days a year was gone. Homestake had cut it up into four-foot chunks and sold it for scrap metal, we would soon learn.

Gone, too, were the

300 workers who had operated this raucous industrial outpost where explosions and thunderous ore dumps had occurred around the clock.

Beyond view lay the dual ore pits, stretching nearly a mile, that are now blue-green lakes. Within view, a lake surrounded by pockets of tule reeds. That’s where the slurry tailings were dumped.

The Homestake Mine is  an oasis of quiet again. Most of the property is now the Homestake Natural Reserve, a vast 7,000-acre spread devoted to environmental education and scientific research within the University of California’s Natural Reserve System.

Working in side-by-side buildings, the last structural vestiges of the mining operation, are five Homestake employees doing environmental remediation and two UC reserve managers who oversee the dozens of researchers who visit each year.

“Why would a university want to partner with a mining company? They’re environmentally awful,” said Cathy Koehler, a wildlife ecologist who lives at the reserve with her husband, Paul Aigner, an evolutionary ecologist.

That’s the conventional wisdom, Koehler said. In fact, Homestake is environmentally wonderful, she said.

Before the digging began, Homestake committed to running a clean operation — clean by mining standards —  and a state-of-the-art cleanup. The Sierra Club ultimately gave the mine its blessing.

Most people would consider the McLaughlin landscape “godforsaken,” Koehler said. If golden grassland and oak forests are your thing, the reserve looks bleak indeed. Yet, this dry scrubbiness is what makes the reserve a superb research site.

Much of the property is serpentine rock, supporting a serpentine habitat where most of the world’s plants cannot grow. Those that do have made special adaptions to the soil’s high magnesium content.

Researchers have come from all over the United States and several foreign countries to study this rare juxtaposition of serpentine and non-serpentine, Koehler said.

Do you want to know what California looked like before Europeans introduced non-native plants? Because the serpentine habitat rebuffs most foreigners, researchers can tease out answers here, she said.

What genetic adaptions are necessary for a plant to survive on adjacent serpentine and non-serpentine soils? The McLaughlin Reserve is the place to find out.

Because serpentine rock emerged when hot springs bubbled up within the past two million years, NASA researchers have come here for clues about how life may exist on other planets, she said.

With the mid-day temperature approaching 100 degrees, Koehler and Aigner headed into the countryside. In the tuck of a hillside, they found Jon Haloin, a Ph.D. candidate at UC Davis, under a green beach umbrella, counting yellow monkey flower seeds.

Haloin has been coming to McLaughlin for five years to run studies on how environmental factors affect yellow monkey flowers. Because the reserve is closed to the public, Haloin doesn’t have to worry about people tromping through his experiments, Koehler said.

This can be brutally hot work, Haloin said. Only in his third year of research did he have a crucial insight: If he brought in an umbrella, he could work in shade, he said.

As a measure of their passion, Koehler and Aigner share one job with one salary while working full-time managing the reserve. On the side, they conduct their own research about how to ward off goat grass, an invasive species.

“You couldn’t get a graduate student to be interested in a project like that,” Aigner said. “It’s not theoretical enough.”

Everyone is interested in gold mines, Koehler said, but the geological history of the McLaughlin Reserve is equally fascinating.

Some 140 million years ago, two tectonic plates beneath the earth’s crust collided. The oceanic Farallon plate dove beneath the North American continental plate, leading to volcanoes and a jumble of rock in the Knoxville area.

Subsequently, the Farallon plate rose back up, creating the coast mountain ranges. Within the past two million years, volcanic vents opened up. Molten rock and geothermal waters came to the surface, depositing minerals, including mercury, silver and gold.

The McLaughlin Mine was located atop the fault that runs through this crash scene.

“Things that used to be low are high and things that were high are gone. It’s an amazing mess,” Koehler said.

When he wrote the book “Assembling California,” a study of California’s jumbled topography, John McPhee visited the Knoxville area with a geologist to observe the many rock types. “This fruitcake, this raisin-in-a-pudding kind of stuff,” he called it.

Homestake’s cleanup manager is Karl Burke. He is implementing environmental remediation plans approved by a host of governmental agencies. The site will probably require monitoring for another 30 to 50 years, he said.

The water in the tailings pond and the ore pit is so hard and mineral rich that it does not support fish life, but it’s not toxic, Burke said. Water fowl enjoy the ponds without harm.

Homestake is studying whether plants in new wetlands bordering the tailings pond will absorb metals harmful to animals. That’s proving not to be the case, he said.

Working in such a bucolic area is a treat, Burke said. “It’s like having your own park.”

Scott Moore is a veteran Homestake employee whose job was once to blast rock in the ore pit. He considers turning a slurry pit into a lush wetland a fine way to end his career. “It’s like taking on a downtrodden ranch,” he said.

Is there still gold at Knoxville? There certainly is, Burke said. Microscopic crumbs too small to glitter are embedded in the area’s churned, geological mash-up.

But Homestake won’t be the one to mine them. The mine, which cost a quarter-billion dollars to put into operation, is gone.

Most of Homestake’s remaining holdings are under a conservation easement with the Land Trust of Napa County that prohibits mining, he said.

In any case, the economics aren’t there. When the mine was operating, the richest ore had only .1 ounce of gold per 2,000 pounds of rock. What remains is even less concentrated, he said.

The miners have moved on. The coyotes, the jackrabbits, the Ph.D. students remain.

Gold in them thar Napa hills

- Homestake Mining Company’s McLaughlin gold mine produced its first gold bar in 1985; its last in 2002.

- To get to the gold, McLaughlin removed 115 million tons of waste rock. Thirty-eight million tons of ore were turned into powder, mixed with water and sent as a slurry through five miles of pipe to a processing plant in Lake County.

- McLaughlin’s two open pits, located mostly in Napa County, produced 3.4 million ounces of gold worth roughly $1 billion at an average market price of $300 per ounce. The pits measure one mile by a half mile.

- The McLaughlin pits were so vast, they gobbled up the remnants of the old Manhattan mercury mine. Manhattan operated from the 1860s until 1978, producing 80,000 flasks of mercury from ore hauled from tunnels.

-The McLaughlin mine is now a 7,000-acre natural preserve operated by the University of California. The area’s rare serpentine rock and habitat offer research opportunities.

- Homestake continues to revegetate rock depositories and turn a slurry dump into wetlands. The pit lake is permanent. The company has won awards for its environmental program.