GOLD - An opportune harvest, but just this once for amateurs.




A Corrida do Ouro na “nova Serra Pelada”  

During 2015, Brazil experienced great political turmoil caused by a relaxation of authority. This resulted in an open access to gold bearing zones especially Pontes e Lacera, a town of about 45,000 inhabitants in southwestern Mato Grosso. This town is located 450 km from Cuiaba, at a latitude 15° 13'34" south and a longitude 59° 20'07" west, with an altitude of 254 meters. It has an area of 8,423 square kilometers.

Fig. 1 -A lot of Gold nuggets – Serra do Caldeirão (1) 

Following the publication in social media of the discovery of giant nuggets, a real gold rush was triggered. Still, about 5,000 garimpeiros are gone to the adventure, abandoning everything. Among those who arrived in Brazilian pastures, there were experienced miners, adventurers, poor people and rich, who had never set foot on an extraction area or even seen the color of gold. So, Wesley Caetano, 19, left his job at a carwash in Indiavaí, a municipality of the region, to find gold. "My Whatsapp was full of images of gold and stories of people who became rich. I thought: it's my chance", he said. 

Fig. 2 - Access to the gold zone is not always easy. Some trails recall the epic of the gold rush in the US in the 19th century (1).

Gold is abundant and some large nuggets were discovered. Nuggets from 10 to 20 grams are not exceptional. However, fine chiselled nuggets are rare. They represent less than 0.1% of the whole. 

Fig. 3 - A giant nugget ! 
This photo is very famous in Brazil. But this is only a painted rock ! (4).

The extraction of sedimentary rocks is with hand or pneumatic drill. The detection in the rocky debris is carried out with metal detectors or gold pan in a few liters of muddy water. Dust is everywhere. New tools and accessories dealers made fortunes as well as farmers who rented parking. 

Fig. 4 - Gold nugget - Serra do Caldeirão claims, Pontes e Lacerda, Alto Guaporé district, Mato Grosso, Br. R. Watzl’s specimen. © R.W.

Parallel aggregates of very sharp and well defined octahedral crystals, with sharp skeletal growths are recently found (end of 2015). These fine crystals (Figs 4 & 6) show a 3-dimensional texture of hoppered growth. The great quality of this Brazil new gold deposit can be considered as the source for world class gold specimens. Skeletal growth, vivid color and exceptional sheen are characteristic of this new ephemeral locality. These fine gold nuggets are out of an exceptional new find during 2015. 

Fig. 5 - Garimpeiro, with a new pick (1).

Fig. 6 - Gold nugget - Serra do Caldeirão claims, Pontes e Lacerda, Alto Guaporé district, Mato Grosso, Br. J. Fabre’s specimen. © R.W.

The deposit is located in detrital relatively crumbly rocks that have undergone hydrothermal alteration. This is not alluvial gold that has been carried along by rivers. It is located in Serra do Caldeirão hills (S 15°18’ – W 59°25’ – 400-500 m altitude), 12 km SW from Pontes e Lacerda.

Fig. 7 - Photo of the mining area taken November 8, 2015 in a flyover Public Security Bureau (Reuters Police / Federal in Mato Grosso).

Much unreliable information was published in the press, especially in the early months. It cited the Serra da Santa Barbara, Serra da Borda, even though the area is included in an APA (Environmental Protection Area). We realized later that this information was unreliable, although the local press and the public thought the gold bearing zone was located in the Serra da Borda, which was not the reality. This is in fact Serra do Caldeirão. The Serra do Caldeirão and the Serra da Borda are aligned in the same direction NW-SE, 

Fig 8 - Serra do Caldeirão claims, Pontes e Lacerda, Alto Guaporé district, Mato Grosso, Brazil (5).

being separated by the Guaporé River Valley. Serra da Borda is to the north of the valley, while the Serra do Caldeirão (SE) is located in the South.

Alas, all good stories have an ending. Affected by the gold rush, the miners who discovered the ore in the region of Serra do Caldeirão, 12 km from Pontes e Lacerda (Fig. 9), digging tirelessly for two months were finally bogged down in Brazilian law, an impenetrable labyrinth of Brazilian mining rights. More than 5,000 garimpeiros were attracted in this site which does belong to various mining companies who have priority rights to gold exploration: Mineração Tarauacá, Mineração Santa Elina, associated with Yamana Gold Inc., Serra da Borda Mineração, also associated with Yamana Gold Inc.

Fig. 9 - Serra do Caldeirão, the Gold paradise, 
12 km NW from Pontes e Lacerda. (Google).

Police has resumed prohibiting access to the region just a few months after this happy discovery. The illegal mining installed on the banks of the city of Pontes e Lacerda was officially vacated by the Federal Police on Tuesday, December 10 2015, but it is far from over. The promise of a new Eldorado in Brazil Western is exacerbating the dispute between those who argue that the gold belongs to the time of prospectors and those who prefer to hand it to a large Canadian multinational (3).

This area is very close to the border with Bolivia where there is a prevalence of drug trafficking and weapons. The Government has long been reluctant to approve the requirements of the mining research. Only after the gold rush, since March 2016, that, under strong pressure to resolve this difficult situation, the DNPM (National Department of Mineral Research) granted the mining exploration licenses in the region. Cattle ranchers possess this region, but they are under the control of mining companies.

Garimpeiros were expelled from the mining pursuant to a court order of eviction. "Mineral resources are property of the Union" explains a note from the Public Ministry of Mato Grosso, which filed the suit. "The extraction without proper authorization from the supervisory body is damage to the heritage of the Union."

Acknowledgments: The authors thank Mr Reynaldo Contreira for rereading and important information defining the context of the Serra do Caldeirão Gold Rush.

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Roger Warin, Jordi Fabre.