The dynamite crew set the charges and ordered everyone back.

They put explosives beneath the miners’ hammocks and in the outdoor kitchen, where potatoes were still hot on the stove. More fuses were placed in the processing shed nearby, which had a blackened torch for melting gold and a rusty barrel of sand laced with mercury.

Get down, a police commander said. Mouths open, another shouted. Apparently it was better for the eardrums.

The blast snapped with a gust of hot air. Wood planks and shreds of zinc roofing leapt upward and somersaulted down. Toucans and macaws scattered into the tree canopy, squawking in protest.

Wearing military fatigues and combat boots, Antonio Fernandez, Peru’s top prosecutor for environmental crimes, watched the mining camp burn. This ghostly moonscape of dead stumps and contaminated pits was primary forest just six months ago, he said.

“These people have done extraordinary damage,” said Fernandez. “We have to respond with the same amount of force.”

After years of ignoring the frantic gold rush fouling the Amazon forests of southeastern Peru’s Madre de Dios region, the government has launched a no-mercy campaign to crush it.

Since April, it has sent police and soldiers on dozens of helicopter raids, swooping down to blow up equipment and burn mining camps. It has cut fuel supplies to Madre de Dios in an attempt to choke off the miners’ generators, motorbikes and diesel engines, saying per capita fuel consumption in the region is 10 times the national average because their machinery runs round-the-clock.

The goal isn’t to bend the miners into legal compliance. It is to drive them out of the jungle entirely. “They don’t belong here,” Fernandez said. “They should go home.”

As many as 40,000 illegal miners — mostly poor, Quechua-speaking laborers from Peru’s Andean highlands — have invaded some of the most pristine and biologically rich sections of ancient forest in the Amazon basin.

In just a few years, they have laid waste to more than 120,000 acres, leaving behind Amazonian deserts of pestilent orange craters that bleed into the rivers when it rains.

Dragging their machinery up waterways and along muddy trails, they chain-saw trees to create space for their dredgers, sluices and the clattering vacuum pumps known as “chupaderas” that can open a pit as deep and wide as a five-story building in a matter of weeks.

While the damage from illegal mining may not be deforesting the Amazon as fast as cattle ranching and agriculture elsewhere have, the destruction is multiplied by the miners’ poisonous little companion: liquid mercury.

They dump it on the sediments they collect to bond with the gold, then vaporize the mercury with torches. It is not a precise industrial process.

So toxic is liquid mercury that the U.S. Environmental Protection Agency recommends calling a hazardous waste specialist if a spill is larger than a broken thermometer. Exposure can cause neurological damage, birth defects, infertility and other health nightmares.

In Madre de Dios, gold miners are putting 30 to 40 tons of the stuff into the rivers each year, according to government estimates. It has leached into nature reserves, the flesh of widely consumed river fish and three-quarters of the adult hair samples tested in the regional capital, Puerto Maldonado.

Nobody knows what the long-term consequences will be. Few of the miners are thinking that far ahead.

“The gold extends 80 meters down, even deeper,” said Luis Otsuka, the president of the local mining federation, an aggressive man with the slightly crazed look of someone living in a prolonged state of gold fever.

Otsuka denounced Peruvian President Ollanta Humala’s campaign against the miners and said the country’s environmental minister “should be killed.”

“They are trying to destroy us,” Otsuka said, channeling local outrage at the government into his candidacy for governor of Madre de Dios. “Our country is so rich, and they want to keep us poor.”

How the process works

Peru is the world’s fifth-largest gold producer, and the biggest in Latin America, extracting about $10 billion worth a year. Less than 20 percent comes from the Amazon.

Most of the gold is mined in the Andean highland by multinational companies from the United States, Canada, Brazil and China.

Jungle gold is different. It has washed down from the mountains in little flecks and chips over millions of years, drifting along alluvial channels with other sediments.

Getting it out of the ground isn’t exactly mining in a traditional sense, and there isn’t much geology involved. It’s more like mechanized soil-filtering.

Using dredgers and vacuum pumps, miners slurp up the sediments and send them through crude wooden sluice boxes. The heaviest particles, weighty with gold, settle toward the bottom and are collected on strips of carpet.

There are no Eureka nuggets or gold seams to strike. The name of the game is volume. The more earth you can suck up and sift out, the more money you make.

Global financial jitters sent gold prices soaring in 2008 and 2009, and they’ve stayed relatively high since then. While American television viewers were bombarded with commercials offering cash for unwanted jewelry, Peruvian laborers went racing into the Amazon.

A few years earlier, the trip would have been a multi-day journey for someone living in the slums of highland cities like Cuzco and Arequipa. But at the same moment that gold prices jumped, highway crews in Brazil and Peru were finishing the long-awaited Interoceanic Highway, the first and only paved road traversing the Amazon basin.

It was meant to boost trade and facilitate Brazilian exports to Asia. Instead, it put millions of poor mountain-folk within a day’s drive of the gold sands.

Peruvian laws have long protected small-scale “artisanal” mining, which allows panning with simple, traditional tools. But the artisanal miners who moved on to dredging equipment got rich and bought more machinery.

Some of the most stunning damage is here in the area known as La Pampa, where thousands of illegal miners have poured into off-limits forest areas adjacent to the Tambopata nature reserve, home of rare giant river otters and white-lipped peccaries. Enforcement was too weak to stop them.

The squalid mining encampments that have popped up overnight make HBO’s Deadwood look like a model village.

The largest is a warren of tarp-covered shacks and muddy streets that fan out from the Interoceanic Highway into alleys of sludge, sewage and trash. Bars and cantinas with plastic patio furniture and $20 teenage hookers share walls with hardware stores, lube shops and nervous-looking men with scales who buy gold by the gram.

It is merely the central supply depot for the miners. Their camps are several miles deeper into the forest.

You reach them along dirt paths wide enough only for a motorbike or three-wheel motor cart. Errand boys zip along the trails on dirt bikes, ferrying fuel, food and laborers between the highway and the camps. A self-
appointed toll collector charges a small fee to keep the rickety wooden bridges from collapsing into the swamps.

There is no police presence or authority. Anyone can arrive with machinery and start digging.

The motorcycle path is more like a busy highway, winding through barren wastes that have already been worked over and abandoned.

The largest, nicknamed Black Fly, is a sandy plain several miles in diameter. A few dredgers were visible in the distance, nibbling at the fringes. It looked like Nevada had landed in the middle of the rain forest.

Other sites along the route were just as obliterated: Mega 11, Mega 12 and Mega 13, each one spanning several football fields.

Adding to the gloom were the burned-out encampments that littered the supply route, where government raids had left charred ruins of tarp villages and debris strewn across the sand: plastic jugs, rusty chains, melted toys.

After 45 minutes, the big pits appeared. Mud-caked men and boys in shorts and flip-flops scrambled up and down eroding walls of sand, grabbing at exposed tree roots, while their vacuum pumps burrowed into fetid brown puddles at the bottom. Thick hoses ran up to the crater rim, spewing out muddy water and sediments onto wobbly sluices.

A few miners were willing to talk and vent anger at the government, which had torched a nearby camp a few days earlier.

“Why won’t they let us work?” asked Ricardo Mendoza, 38, guiding a vacuum with a mouth as big as a dinner plate through the muck while his partner rode a pontoon raft, yanking at the levers of a floating dredger.

“I have five kids,” said Mendoza. “I just want them to have a better life.”

As a farm laborer, he made $10 to $15 a day. Here in La Pampa, he said, he earns five times that.

Concerns about campaign

“Extreme profits are never a justification for breaking the law,” Manuel Pulgar-Vidal, Peru’s environmental minister, said in an interview.

The four-month-old campaign against illegal mining has won praise abroad and public support in Lima, Peru’s capital, even as anti-government protests turned deadly in Madre de Dios and the country’s gold output dropped 14 percent after the crackdown.

The aerial images of the destruction were too appalling to ignore. They had become a national embarrassment.

Pulgar-Vidal and others are pushing to tighten regulations and steer the miners toward more formalized practices and permitting, a process the miners say is a sham.

Real enforcement will require more time and more muscle: investigative work, additional prosecutors, and a bigger police and military presence in the gold-rich areas. The government will have to make sure its regulators can’t be bought off as easily as in the past.

Despite the helicopter raids and TV-ready demolitions of equipment, Peruvian prosecutors have sent just four illegal miners to prison.

Usually there is no one for them to arrest when they land. The miners and their families grab their most valuable machinery and possessions and flee into the forest when the helicopters approach. There isn’t any room for them in the helicopters anyway — one reason the government wants their equipment destroyed on site.

“What’s the point of seizing machinery and hauling it out of here if a corrupt judge can just give it right back?” said one military commander leading the raids, who spoke on the condition of anonymity because he wasn’t authorized to give interviews.

He estimated they had hit about half of the largest illegal sites in La Pampa. When they fly over them a few days later, he said, they often find the camps rebuilt and the dredgers running again.