OIAPOQUE, Brazil - An informant has passed along rough GPS coordinates for the whereabouts of an illegal gold mine. It’s mid-morning, and a small group of army soldiers are huddled next to two military helicopters receiving their final briefings.

But this is no ordinary mission. 

This is the border between the Brazilian Amazon and French Guiana, a densely covered jungle region, and the only way to mount an operation to the gold mine is from helicopters. The forest extends for hundreds of miles and can’t be penetrated by car, ground troops, or even a tank.

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Security forces gather before a mission into the jungle. [Maria Elena Romero/Al Jazeera]

The helicopters take off from a small Brazilian army base in this muddy frontier town of Oiapoque, population 20,900.

Only a river divides Oiapoque and the village of St. Georges, French Guiana.

The helicopters are flying at low altitude over spectacular, untouched native forest.

Finding an illegal gold site in this vast expanse is nearly impossible without the GPS coordinates.

After almost 45 minutes, it appears in the distance. It’s a crater-like hole in the jungle, carving a deep scar in the earth.

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The gold mine site, as seen from the air. [Maria Elena Romero/Al Jazeera]

The destruction is created from high pressure power hoses used to blast through the earth in search of gold. It’s a clandestine gold mine, at least a kilometer or two long. The intel was spot on.

The helicopters circle a few times, probing for a safe place to land.

After landing in an open space, soldiers jump out and run to an area where they see some men.

Most of the workers on this gold mine likely fled into jungle when they heard the helicopters above.

Four remain, and they are apprehended and questioned. They’re wet and muddy, poor labourers brought to work with the promise of a cut of the profits if gold is found. Like most workers at illegal Amazon gold mines, they don’t have any identification.

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Soldiers stand guard over poor gold prospectors. [Maria Elena Romero/Al Jazeera]

They say the gold mine has been around about 5 years. There are generators, shovels, plastic boots, pipes, a few rudimentary shelters made from sticks of wood with a tarp for a roof.

Less than a kilometer away is a clandestine landing strip, indicating someone with money was financing this operation.

The mine appears to be at least partially abandoned. For the government, it’s critical to identify places like this and shut them down.

(Watch a video report on illegal Brazilian gold mining.)

“They are removing land and there is deforestation, totally illegal,” Alan Jose de Almeida, a federal police agent who accompanied the military operation, told me at the mine site. “And oftentimes these illegal mines are linked to other crimes, like unauthorized possession of firearms, wildlife trafficking and sometimes even drug trafficking, so it’s important we find them and shut them down.”

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A soldier, wearing a patch on his shoulder that says 'jungle operations'. [Maria Elena Romero/Al Jazeera]

The air force might come back another day to bomb the landing strip so it can’t be used in the future. 

In another location, the army identified 10 clandestine landing strips within indigenous reserves. They said it was used for gold mines and possibly drug trafficking.

There are hundreds - maybe thousands - of illegal gold mines like this one in the Amazon. Some become so big, they end up turning into small gold rush cities. 

But most times, reaching such remote locations in the jungle requires a military-like deployment of forces, and this operation was just that, part of an unprecedented 8,600-soldier deployment from all three branches of the Brazilian military to the northeast Amazon border region to crack down on illegal mines, logging, contraband, drug trafficking and transnational crimes.

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Soldiers preparing for a night patrol on a jungle road. [Maria Elena Romero/Al Jazeera]

The operation, named Agata 4 by the Ministry of Defence, is taking place in a 5,000-kilometer area of the Brazilian northern border - stretching west from the point where Brazil, Colombia and Venezuela meet east to the Brazilian border with French Guiana.  

“This is one of the biggest such operations we have ever done,” General Eduardo Villas Boas, the Amazon region's top military leader, told me from his command center in Manaus this past week. “Agata 4 is part of a strategic border plan from the federal government.”

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General Villas Boas commands the entire Amazon military operation. [Al Jazeera]

This isn't the first time Brazil has massed soldiers at their borders, and won't be the last. There simply are not enough agents from any one agency to do it alone.

In Oiapoque, the city nearest the illegal gold mine, there was only one federal environmental enforcement officer  before this operation.

Brazil has about 17,000 kilometers of border with 10 countries and about 11,000 kilometers of it is covered by the Amazon forest - some of the most remote and unforgiving area in the world. 

“Due to the geographic conditions, this is a border area that is hard to monitor, and that is why it’s important to do operations like this one,” Villas Boas said.

It’s also a highly sensitive region, bordering Colombia, Bolivia and Peru, the three countries that account for almost 90 per cent of the world’s cocaine production.

(Watch a video report on drug trafficking through Sao Paulo airport.)

Because of the porous borders, in recent years the Brazilian Amazon has become one of the preferred routes for cocaine smuggling from the Andes of South America.  Much of the product winds up in medium-sized cities on the Brazilian coast where they are flown to Africa and then Europe. Increasingly, the drugs end up in Sao Paulo, where they are given to human mules to be transported abroad.

The federal government is trying to avoid allowing Brazil’s Amazon border region become a complete no man’s land of drug turf wars and uncontrollable violence.

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Solderis use speed boats to patrol the Rio Oiapoque, near French Guiana. [Maria Elena Romero/Al Jazeera]

The Brazilian Army has 122 outposts in the Amazon region in 56 municipalities, but the new military deployment seems to be an indication it’s not enough, and that more troops are needs to provide security.

“The Brazilian territory is huge, and the borders are very extensive and difficult to access, so the Brazilian state has difficulty to create a complete structure in this part of the national territory,” army General Humberto Francisco Madeira told me from a base in Oiapoque. “The armed forces have had a presence here historically, and maybe in some places we are the only presence of the state.”

Operation ‘Agata 4’ is meant to change that.

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Madeira explains the complexity of Brazil's Amazon borders. [Maria Elena Romero/Al Jazeera]

Military commanders say they are not looking to make large scale arrests, a task best left to the federal police, but rather to secure some of the most unwieldy border areas to allow other government agencies to work.

Still, there is a lot of policing work being done by the military.

On most nights while this operation continues, soldiers with machine guns patrol the Rio Oiapoque on speed boats, pulling over and searching suspicious vessels.

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A navy trooper, wearing a mask, searches a river boat. [Maria Elena Romero/Al Jazeera]

The military operation is expected to last several weeks, but commanders say the federal government has given no end date.

Back at the gold mine site, a couple federal police officers and agents from environmental protection agency document as much as they can in notebooks and take pictures. Soldiers stand guard. But beyond that, there is little more that can be accomplished here, the environmental damage has been done.

This site will be shut down, but the truth is that once the latest troop deployment is over, it could be years before any Brazilian government agency visits the site again. 

For now, there is little time to linger, the troops have to get back to base to prepare for tomorrow.

There is fresh intelligence on the location of another possible illegal gold mine in the jungle.

Follow Gabriel Elizondo on Twitter @elizondogabriel.