Gold Occurrences in Brazil

Coat of Arms of Brazil

Within its borders Brazil is the fifth largest country in the world; it touches upon all the countries in South America except Ecuador.  The country also has an astonishing variety of mineral deposits including iron, gold, gemstones, diamonds and oil.  There are literally hundreds of active mining companies found in Brazil.  Brazil also enjoys a rising economy and has a stable government with the future for mining being extremely bright.

The Amazonian shield covers much of the eastern portion of the South American continent and provides many of its gold mines.  Prospecting in the area is similar to prospecting in Canada’s Abitibi Gold Province in Ontario with a repeat of its greenstone belts with alternating gneiss’s.  There are also many deposits of turbidite hosted paleo-gold deposits similar to those found in the Witwatersrand in South Africa.  To the north of the Amazonian shield is the Guyana shield, to the south are the Rio Apa and Platian cratons and in the west is the Sao Francisco craton.  All of these areas are gold bearing.

Brazil covers 8.5 million square kilometers with 7,500 kilometers of coastline making it the largest country in South America, a size that dwarfs all its neighbors.  Its size is on continental size contains a vast resource base making it a prime target for attracting foreign investors and miners as well as Brazilian mining companies.  The country also has a long history of gold mining dating back into the 16^th century.

It is estimated that less then 30% of the country has been adequately mapped so there is plenty of room for prospecting in both placer and lode gold deposits. Placer deposits can be found throughout Brazil except in the depths of the Amazon Basin, and there are plenty of gold deposits found in the Precambrian Shield areas that dot the country.

One of the biggest problems facing the Brazilian mining industry are the number of artisanal mining operations that keep popping up; there was a gold rush in the 1990s that centered on the Guyana shield that reportedly attracted over 90,000 miners to the area.  These miners for the most part disregarded good environmental practices resulting in large areas that were contaminated with mercury and other contaminants.

It has been found that artisanal mining is today the largest source of mercury release into the environment not only in Brazil but other countries too.  One of the sites mentioned that is the largest is in the Tapajos River Basin in the Amazon region of Brazil.  The Global Mercury Project (GMP) under the auspices of the United Nations is aiming to reduce this mercury contamination.

Brazil as a whole is mining friendly and enjoys a now stable government and a rapidly expanding economy that welcomes miners from around the world.  There are still vast amounts of the country that have not been explored, so one never knows what might be found just around the next bend of the river.

Gold Occurrences in Colombia

Plate tectonics found in Colombia.

It doesn’t happen very often, but Colombia was the subject of a whole section in Engineering and Mining Journal (E&MJ) all about the boom in minerals there.  Colombia is the northern terminus of the Andes Mountains that is also one of the last areas in the Andes to be explored for minerals.  Even the author is interested in the goings on in Colombia because his friend Nick is developing a mine that is located between the Pig Pen and the Old Man in the northern Andes.  We have been consulting on this mine for the past year and although it is beyond the range of the internet Nick gives us regular reports on his progress whenever he gets into town.

Colombia has three different distinct areas where gold is found.  One of these areas is in the Andes proper where it is found as epithermal deposits in shear zones.  The area also contains placer gold. The second area is in the Sierra Nevada de Santa Marta Mountains in the northeast of Colombia.  These mountains are not part of the Andes, but rather are a distinct mountain range in their own right that has the distinction of being the highest coastal range in the world at 5,700 meters (17,760 feet).  Although these mountains are reported to contain much gold it is protected by a tribe of Indians that were never conquered by the Spaniards that take a dim view of gold seekers that are after their gold.  The third area is in the Guyana Shield a large group of Precambrian Rocks that are found in the southeastern part of the country where they continue into Brazil, Guyana and Venezuela.

E&MJ considers Colombia as the last frontier of the Andes Mountains because so much has already been discovered in the Andes further south.  Gold is the least of the mineral wealth of Colombia the country is already the home of the largest deposits of emeralds on earth with finds dating back to the days of the Incas.  Colombia also contains coal measures that are largely being exported to Europe.  One company Xstrata produces high grade coal from its Cerrejon mine the largest in Colombia.

Getting back to my friend Nick in his prospecting he has discovered a pegmatite in the part of Colombia where he is prospecting that contains crystals of aquamarine of euclase,   This will show you that much more then gold can be found in Colombia.