The explosion detonates in a gorge hours later, while a separate blast elsewhere sends chunks of metal flying.

The resounding booms signal the Ecuadoran army's attempt to crush illegal mining operations, which are run by criminal groups in the northern La Merced de Buenos Aires region near the Colombian border.

AFP witnessed these attempts in action while accompanying an operation into the rugged terrain, where soldiers covering their faces "for security" patrol on foot, sporting rifles, helmets and bulletproof vests.

The army has gone as far as using tanks, BM-21 rocket launchers and mortars to attack illegal mines in several areas.

The mountainous region "has great wealth that has not been tapped," said operation leader Colonel Christian Ruales.

In 2019, security forces evicted around 3,000 miners from the mountains in what was one of Ecuador's largest operations against illegal mining.

According to Ruales, the presence of soldiers is essential to curb the practice.

"Otherwise, this would flare up again," he said, warning of further illicit projects emerging.

- Money maker -

"They're coming to blow it up," the voice crackles through the radio again, warning that the "greens" -- the soldiers -- are approaching.

Despite the constant military presence, gold extraction is going full steam ahead, with the precious metal's value reaching a record of almost $5,600 per ounce in January.

The illegal trade yields even higher profits than drug trafficking in some Latin American countries, according to the Ecuadoran Chamber of Mining. And in Ecuador alone, between 60 percent and 70 percent of gold mined is illegal, generating more than $1.6 billion annually.

"I see raids, but mining doesn't stop," Brian Proano, a food vendor and former illegal miner told AFP.

"Mining is going to continue because there's no work out here," he added.

- Power struggle -

The activity spells both environmental and social problems in La Merced de Buenos Aires.

AFP saw traces of chemicals like cyanide discarded by a clandestine gold refinement facility on a riverbank, exuding a thick liquid and a strong, vinegar-like odor.

The Oliver Sinisterra Front -- a dissident group of Colombia's now-defunct rebel army FARC -- is active in the region.

Local gold exploitation sparked a power struggle between the front and the Ecuadoran gang Los Lobos.

Tied to Mexico's Jalisco New Generation Cartel and boasting thousands of members across the country, Los Lobos is one of Ecuador's "most powerful and innovative criminal organizations," according to non-governmental group Insight Crime.

The gang engages in illegal mining and has even co-opted some legal operations, the NGO says.

With US backing, right-wing President Daniel Noboa's government is attempting to crack down on crime groups.

With little effect, however.

Homicides in Ecuador have increased, ticking up to over 9,200 violent deaths last year -- a record high.