Rising up through the lush vegetation of Panama's Caribbean coast, a 125-meter chimney serves as a beacon for helicopters approaching the largest mine in Central America, which faces closure next week over a contract dispute.
Gigantic 400-tonne trucks slowly wind around the stepped slopes of a massive gash in the earth one kilometer wide, the ochre and grey of the copper mine standing in stark contrast to the verdant jungle surrounding it.
The activity could grind to an expensive halt in a matter of days.
Canadian mining giant First Quantum Minerals has until next Wednesday to sign a new contract with the government, which is demanding the company multiply the taxes it pays by 10.
If the parties do not agree, the disagreement could halt the work of a mining project considered the largest private investment in Panama's history, contributing four percent of the country's GDP and 75 percent of export revenues.
"We have been given a deadline to sign the new contract by December 14, to accept the new terms," First Quantum's manager in Panama, Keith Green, who is Scottish, told AFP.
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"We intend to reach an agreement, but negotiations are a bit deadlocked," he added.
First Quantum, one of the largest copper miners in the world, began commercial copper production at the site in Donoso in 2019, through its subsidiary Minera Panama.
It has spent $10 billion on earthworks, construction buildings to house more than 7,000 employees, the purchase of heavy machinery, a power plant, a port for deep-draft merchant ships, access roads, and re-forestation plans.
President Laurentino Cortizo in January announced plans to toughen the conditions of the mining license, with a new contract that would oblige the mining company to pay "at least" $375 million to Panama annually -- ten times what it is currently paying.
"Panama has the inalienable right to receive fair income from the extraction of its mineral resources, because the copper is Panamanian," he said.
This mine is "the biggest in Central America," producing 300,000 tons of copper concentrate per year, said Green.
The deposit, discovered in 1968, lies on the Caribbean coast, 240 kilometers by road from the capital Panama City.
The company, listed on the Toronto Stock Exchange, built the Punta Rincon International Port next to the mine to transport the copper by ship, due to a lack of roads connecting the Colon port, 40 kilometers (25 miles) away.
Despite the uncertainty over the mine's future, activity has not slowed and the company has continued to invest in the site.
A new 200-tonne drilling rig -- as tall as a three-story building -- was inaugurated in a ceremony on Tuesday, causing heavy air traffic.
Helicopter pilot Oldemar Arauz explains that most officials visiting the mine prefer the one-hour air trip to the four-hour drive on a narrow road from the capital.
The drilling rig, made in the United States by the Swedish company Epiroc, cost $6 million, and was transported to the mine in 10 trucks.
"Latin America has 200 of these drills, 50 in Chile and now three in Panama," said Epiroc's Latin America manager Hans Traub.
The drill was assembled by Chilean engineer Alex Gonzalez, who previously worked in Chuquicamata, the world's largest open pit copper mine, situated in the Atacama desert, which has been operating since 1915.
Central America does not have the same mining tradition seen further south. Mining is illegal in Costa Rica and El Salvador, and while there is much potential for growth in Panama, the industry's future is now hanging in the balance.