Admilson Nogueira, an Apui councilman, told Reuters by telephone on Monday: "They came from all over, it's created a mining frenzy. Priests, politicians and peasants alike are trying their luck."
With shovels and axes they dig garage-sized lots two metres deep into the heavy clay soil, panning the earth at a nearby branch of the Juma river, he said.
Environmental authorities say that they fear deforestation and contamination from the mercury that garimpeiros use to bind the gold into nuggets.
Mario Jorge, interim inspection chief at the environmental protection agency Ibama in Manaus, said: "They are devastating the area, there is a real risk of mercury contamination of the rivers."
A delegation of environmental and mining authorities is to travel to the area on Tuesday to determine whether to grant an operating licence or have the miners removed.
In reference to a wildcat mine in the Amazon that drew as many as 30,000 garimpeiros in the 1980s, Jorge said: "If we don't control this now, it could turn into a Serra Pelada."
|"They are devastating the area, there is a real risk of mercury contamination of the rivers"|
Images of the slave-like working conditions in which haggard, mud-drenched miners carried bags of earth on their shoulders at Serra Pelada became world famous through Brazilian photographer Sebastiao Salgado.
Walter Arcoverde, head of inspection at the mining ministry in Brasilia, said that with the recovery of the price of gold, poor people throughout the region are again hoping to strike it big.
Arcoverde said: "It's not as big as the rush of the 1980s but the number of garimpeiros is on the rise again."
He said that Apui lies in the heart of a region with large potential alluvial gold deposits.
Some people have mined as much as 500 grams over the past month, according to Nogueira, making around $9,112.
The environmental protection agency wants to allow mining under supervision, but Jorge has said that there could be several health risks, including an outbreak of malaria.
As the mine pit fills with stagnant water, mosquitoes carrying the disease multiply quickly and infect the miners, he said.
But authorities may be spared a tough decision.
Nogueira said: "Garimpeiros go as quickly as they come, it all depends how much gold they find."