At the end of a dirt road lined by modest huts, in the municipality of Simoes Filho, some 60 people were digging up the earth, creating a noisy clatter of picks and hammer.
Children just five or six years old carrying spades taller than them zig-zagged between deep holes two meters (six and a half feet) deep.
Rinaldo, a 24-year-old prospector who declined to give his last name, started digging on Tuesday, joining 500 people in attacking the ground with tools or their bare hands looking for the clumps of grey-white mineral.
"The deposits are getting smaller. I only picked up seven kilos on Wednesday," he complained.
Indeed, all signs are that the euphoria will evaporate within days.
The mayor's office of Simoes Filho said the manganese found under the ground probably was not even a natural deposit.
"This manganese was left her by (the Brazilian steelmaking company Sibra) 30 years ago. Around 20 days back two kids playing in an empty lot found a strange rock. When they broke it open they found what looked like aluminum inside. That got people curious," explained the mayor's spokesman, Carlos de Oliveira.
According to locals, Mapele had often been used as a dump by several companies in the region.
"One this is shore, it's not a lode," Pedro Ricardo, the head of the Center for Environmental Resources for Bahia state, told AFP.
"This sort of ground isn't favorable for deposits. The manganese is too close to the soil for it to come from a mine," he said.
Nevertheless, the poor inhabitants have leapt on the find as a financial windfall offering a better return than the subsistence fishing they usually rely upon.
Initially, they received 0.70 reals (40 US cents) per kilogramme from traders - a small but significant amount in a community where most people were unemployed and the average monthly salary was less than $200.
The traders were selling the manganese for around 10 reals ($6) per kilogramme.
But with the source disappearing fast, the prospectors were demanding a bigger cut: two reals a kilogramme.
The traders purchasing the mineral were unknown to the locals.
"They come, weigh the merchandise, pay and then go after filling their cars," explained Cristina, a woman in her 30s who said she had extracted 20 kilogrammes of manganese on Wednesday.
The sensation the mineral find had stirred, and the presence of the media, appeared to have scared off most of the traders on Thursday, prompting hostility by some of Mapele's young men towards journalists.
A Brazilian television news crew was targeted for a hail of stones.
Two traders who did turn up asked a few questions but left without buying any manganese, apparently dissatisfied with the higher price being demanded.
Some locals had made hay at the opportune moment.
"I picked up 200 kilos in two days," said Erisvaldo, a fisherman in his 20s. "It was raining so I couldn't fish and I came here. In all, I earned 140 reals."
Technically, the recovery of manganese from the ground is illegal without a mining license. But municipal officials did nothing to stop the rush.
"We're going to let them finish picking everything up. It won't last very long," predicted De Oliveira.