Gold has a history dating back to 4000 B.C. with
traces of usage in Eastern and Central Europe. By 1500 BC, it had become a
medium of exchange in Egypt. Gold mines were predominantly located in Asia
Minor though later by 500 A.D mines were discovered in Central Europe and
France. Gold was widely used in Central and South America.
In the 16th and 17th centuries, Spanish conquests to
Central and South America and subsequent massacre of local population were
linked to bring back gold from Central and South America. Gold was discovered
in US in the late 18th Century. US linked dollar to gold in 1792
which was to continue till 1973. Explorations of new lands led to finding of
gold in Australia
and Southern Africa.
History of gold as a money spanned from about 700 BC
till about 1930. The First World War (1914-18) and the Great Depression of 1929
resulted in many countries abandoning the gold standard. In 1933, President
Roosevelt of the US
banned gold exports, halted the convertibility of dollar bills into gold, and
ordered confiscation of gold in the possession of the citizens. In the
aftermath of the World War II, the Bretton Woods System launched the new gold
standard system in 1945
The Bretton Woods agreement virtually pegged the
dollar to gold, an outcome being the dollar emerging as the reserve currency of
the world. Dollar outflow from US in the
immediate post Second World War years ostensibly was to promote competitiveness
yet it only increased the US trade deficit. The US had encouraged the outflow
of dollars from 1945 to 1958 to promote competitiveness and growth in Europe
and Japan. By 1958, the US
trade deficit had swung negative while its gold reserves had increased only
marginally. This was leading to situation wherein the US would face
shortage of gold to redeem the dollars held by the countries. It was described
as Triffin Paradox. The US ultimately abandoned gold standard in 1973 leading
to collapse of Bretton Woods system.
Gold apart from being used for jewelry and as a store
of value was used for a host of industrial and commercial applications. It was
completely recyclable and all the gold that had been mined since the beginning
of mankind still existed in some form or the other. It was virtually immune to
air, water and oxygen. It did not tarnish, corrode or rust. It was ductile and
malleable. All these factors made gold the preferred metal for jewelry. Being
highly reflective and exhibiting least absorption and thermal conductivity enables
gold to find application in space and firefighting industries.
Gold was being mined for hundreds of years. It had
been first found on the beds of rivers and creeks and came to be known as
alluvial gold. Later the mined gold came from beneath the rocks sometimes
thousands of feet below the ground. Gold mining involved using of advanced
technologies including satellite mapping for identifying and analyzing the
prospective reserves.
Drilling and engineering involved examining samples of
rock for traces of gold and determining the size of the deposit, depth and
grade. The drilling took place at several locations and the samples collected
were chemically analyzed. Analyzing the results would lead to identification of
right location for mining based on consideration of depth of deposits, topography
of the surrounding terrain, difficulty in reaching and bringing out gold,
presence of water and potential impact on environment and wildlife. Decision
was also taken whether to go in for open pit mine or underground mine. Experts
believed that it took nearly five years from the discovery till the start of
actual mining of gold.
Holes are drilled for blasting and samples are
examined for their characteristics. Based on the metallurgical property, the
ores are sent to different processing machines. The low grade ore was broken
into mall chunks and a dilute solution of cyanide was passed over it. Cyanide
dissolves gold and this solution was collected for further processing. The high
grade ore was sent to grinding mill to convert into powder and based on its
characteristics was directly sent to leaching circuit which involved passing
cyanide solution onto gold or an indirect process of either carbon refractory
ore or sulfide refractory ore after which the gold was sent to leaching
circuit. Gold treated with cyanide was absorbed onto activated carbon, and then
moved into a vessel to chemically remove the carbon and then extracted through
electrolysis. The impure gold was belted into dole bars and sent to refineries
to purify the gold.
Refining involved the separation of gold from other
metals. First crude gold was melted and chlorine passed over it to absorb the
other metals. This yielded 99.5% pure gold and was cast into anodes. Through
electrolysis, 99.99% of the gold was deposited in the cathode.
On exhaustion of reserves, gold mines are abandoned,
yet strict environmental standards mean, detailed plans need to be submitted
for reclamation of the land and restoring the site to its natural state.
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