by Pedro Jacobi

Historical Background: gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

Following a simple principle that a world class deposit should have a world class signature in 1997, Pedro Jacobi and Alain Lestra selected five major gold bearing structural/geological anomalies in Tapajós. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

V3 was amongst them. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

In a couple of months a field team led by Alain Lestra and Paulo Andreazza started the exploration work in the selected targets. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

At V3, preliminary grid results were disappointing (a few anomalous gold samples returned from the large grid) and the area was receiving a lower priority. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

Nevertheless a single rock sample changed the overall story. It was a weathered gossaneous, altered-micaceous rock, called a quartz-sulfide-mica-schist in the field. Due to unusual amount of sulfide derived goethite this rock was milled in the field yielding >2g/t Au. Similar results are common in some areas in Tapajós but the soils, close to the rock site, were dead, just around background. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

It was decided to review the area. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

In the subsequent follow-up the geologists found a large outcrop of gold bearing, sulfide rich and intensely altered acid breccia.

Latter, during a second expedition this group led by Pedro Jacobi established that V3 was a large epithermal system related to a buried intrusive pluton.

Most of the gold was trapped in the goethitic and gossaneous fragments in the soil's coarser fraction. As such a minus 80# fraction could not produce any anomalous result.

The field sampling procedure was changed. Bulk soil samples outlined a large soil anomaly were previous sampling didn't. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

It was discovered the first gold-copper-silver epithermal deposit of Tapajós. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

Geology and Mineralization: gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

V3 is a large epithermal system containing gold and traces of copper. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

The V3 discovery hill sits 300m above the local surface. This topographic anomaly is due to the intense silicification that occurred on the upper portion of the V3 volcanic center. This center may be related, in depth, to intrusive porphyry bodies (see sketch). V3 is associated to a conspicuous gamma (U/K) anomaly and close to a mag one. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

Like other epithermal/porphyry deposits V3 has a conspicuous chemical fingerprint. Most important elements are Au, Cu, Ag, Pb and As. High values of Mo, Bi, Sb, Y, La, Zr, Ba, and Te are frequent. V3 gold carries anomalous PGE (mostly Pd) values, that may reach up to 15% in analyzed nuggets.

V3 system is characterized by an intense, pervasive alteration process, which has formed conspicuous haloes. Main alteration style is argillic (pyrophyllite-kaolinite-dickite) followed by a phyllic (quartz-sericite-pyrite) assemblage. Propylitisation (carbonate-epidote-gypsum-chlorite) is confined to the more intermediate volcanics which occur deeper in the epithermal edifice. Allunite is not as common as the other alteration minerals. Potassic alteration is rare. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

Pyrite, which is the main sulfide, occurs in all rock types as dissemination, blebs and masses forming a conspicuous pyrite outer shell. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

A large volume of fluids has percolated trough the top portion of this volcanic system changing and obliterating textures and minerals.

Main geological units are: gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

Hematite-silica-pyrophyllite rich breccias: Hematite breccias are capping the sulfide rich ones. They occur as deep as 100m. Hematite was formed as a result of the oxidation of sulphur-gold-copper-silver bearing fluids, during Proterozoic. Most clasts have been totally replaced by pyrophyllite, hematite and silica.

This unit hosts the main gold and silver mineralization of V3. Native copper specks are frequent.

Sulfide-silica-pyrophyllite rich breccias: These breccias were developed under the hematite zone. A transition zone of few meters occurs in between these two environments. An intense silicification and sulfidation of the pre-existing volcanics characterize this unit.

After initial sealing, late stage fluids broke trough the rock developing a typical crackled breccia. Crackled breccias have unusual amounts of pyrite. Pyrite occurs disseminated, in blebs and massive clasts, and in fine-grained masses, associated to the quartz filling late stage fractures. Late stage Py carries gold and some silver. Accessory minerals are andaluzite, ilmenite and some rare rutile. Chalcocite and covellite are the main copper minerals. Chalcopyrite is rare. Breccias are non-magnetic rocks.

Several hydrothermal pulses developed different generation of breccias. gold, copper, molly, mineral exploration, brazil, amazon, geology, consultant, properties, minerals, tantalite, porphyries, consultants, quartz, amethyst, diamonds, tapajos, garimpo, garimpeiro

Underneath the silicified breccia zone, it was intersected a volcanic pile underlain by acid to intermediate (dacite to andesitic) volcanics, tuffs, lapilli tuffs, ignimbrites, dacite porphyry and autoclastic-hydrothermal dacitic breccias. ouro, cobre, molibdenita, pórfiros, exploração mineral, amazônia, brasil, geologia, consultor, áreas, garimpos, minerais, quartzo, tantalita, ametista, citrino, diamantes, tapajós,

Main gold mineralization at V3 is of supergene nature and stays always close close (30m) to the surface. In deeper portions gold is associated to the highest Py concentrations. ouro, cobre, molibdenita, pórfiros, exploração mineral, amazônia, brasil, geologia, consultor, áreas, garimpos, minerais, quartzo, tantalita, ametista, citrino, diamantes, tapajós,

V3 is part of a large Proterozoic event that generated a number of volcanic centers related to late stage shallow intrusions in caldera margins. ouro, cobre, molibdenita, pórfiros, exploração mineral, amazônia, brasil, geologia, consultor, áreas, garimpos, minerais, quartzo, tantalita, ametista, citrino, diamantes, tapajós,

All targets have a characteristic chemical fingerprint (Au, Ag/Cu/Mo, /Sb/As/Te/Pd) which was unknown in Tapajós and other Brazilian Proterozoic terrain. ouro, cobre, molibdenita, pórfiros, exploração mineral, amazônia, brasil, geologia, consultor, áreas, garimpos, minerais, quartzo, tantalita, ametista, citrino, diamantes, tapajós,

V3 is a large (>100Mt), low grade, open-pittable gold deposit that may be mined in the future if infrastructure and prices allow. ouro, cobre, molibdenita, pórfiros, exploração mineral, amazônia, brasil, geologia, consultor, áreas, garimpos, minerais, quartzo, tantalita, ametista, citrino, diamantes, tapajós,

As a result of this discovery several other Cu-gold-molly porphyry-epithermal deposits were found by Rio Tinto in Tapajós. ouro, cobre, molibdenita, pórfiros, exploração mineral, amazônia, brasil, geologia, consultor, áreas, garimpos, minerais, quartzo, tantalita, ametista, citrino, diamantes, tapajós,

The most interesting ones are V6 and V7 were Cu-Au-Mo grades are higher and were a chalcocite blanket was developed. ouro, cobre, molibdenita, pórfiros, exploração mineral, amazônia, brasil, geologia, consultor, áreas, garimpos, minerais, quartzo, tantalita, ametista, citrino, diamantes, tapajós,

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