Gold mining operations soon went through an industrial revolution.  The gold rush in Australia resulted in the largest nugget ever being found, a 70kg block of gold.  At the end of Winter and beginning of Spring in 1876, whilst General George.A.Custer was preparing for his infamous meeting with Little Big Horn, brothers Fred and Moses Manuel began looking for gold in the Black Hills of South Dakota.

Born in Quebec, the Manuel brothers spent most of their lives surveying the West of the USA in the unlikely search for gold.  Like many before them, they had heard rumours that General Custer’s geologists had found gold in the Black Hills.  On the 9th April 1876, the two brothers discovered what they were looking for in a known area called Bobtail ravine.  Moses relates their discovery in his diary: “finally the snow began to melt on the hill, water drained from the filter through the pipe.  There, I saw quartz! I took hold of a pick to try and break off a block but it was very compact.  I still managed to break off a piece and returned to camp to crush it and wash it.  It was full of gold”

Homestake gold mine in 1877

In just a few months, Fred and Moses Manuel extracted five thousand dollars worth of gold, a small fortune at the time.  One year later, the two brothers sold their mine for 45000 dollars.  The deposit became one of the first properties owned by the Homestake Mining Company.  The creation of the Homestake mine signalled a revolution in gold mining operations.  In the centuries that followed, the solitary gold hunter equipped with just one pan and one shovel gradually gave way to larger companies using new technologies.  One of the most efficient methods but also the most destructive for the environment consisted of hydraulic mining operations.  It consists of sending water through an enormous hose nozzle and projecting it with extreme force against a rock to break off large pieces.  By literally sweeping away the quartz, gold appears.”

The water canons destroy millions of cubic metres of earth and rock on hillsides, using pressures which could mutilate or kill a man from 30 metres.  In less than a day, a clean sweep can be made of a riverbed which would take an army of prospectors armed with shovels and pans a month to sift through.  Old mining sites dating from the first gold rush came back to life.

Another aid came in 1889 for mining companies in the form of cyanide, a deadly poison for humans but a great help for industry.  “We realised that cyanide had the power to dissolve rock around gold.  It became very economic for industry to use large scale techniques and therefore recover small deposits of gold.” Gold cyanidation  is a metelurgical technique for extracting gold from low-grade ore by converting the gold to water soluble aurocyanide metallic complex ions. It is the most commonly used process for gold extraction. Due to the highly poisonous nature of cyanide, the process is highly controversial and its usage is now banned in a number of countries and territories.

These technological advances turned the mania at Homestake into the richest mine in US history.  For over a century it has continued to produce gold in regular quantities.  It represents 10% of all gold extracted from mines in America.  Fred and Moses Manuel discovered one of the largest reserves of gold scattered across Western America.  Many years later, geologists discovered a gold field of more than 1600 metres deep and 1600 metres long in the mountains of Nevada, but the gold remains invisible to the naked eye

Today the mining company Barrick uses innovative techniques to recover microscopic grains of gold just a few thousandths of a millimetre in size.  To see them, they need to be enlarged about 2000 times.

After the discovery of deposits in the Carlin region as well as the implementation of modern technologies, the US has become the second largest gold producer in the world.

The discovery of the largest gold reserves are located in one of the most profitable and outstanding geological environments on Earth.  Thieves know that the gold is capable of revealing their fingerprints using a new type of chemical analysis which is most notably capable of precisely indicating where the metal comes from.

Tags: Environment, Gold

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