From ancient times to famous gold rushes, gold was first discovered in placer deposits. Placer gold occurs when host rock weathers and releases gold particles that travel downslope to a hillside, canyon mouth, or streambed.
Today most gold comes from hard rock deposits, where gold is disseminated, or associated, with other metals and mined either through open-pit or underground mining. Gold deposits form when gold is dissolved in hot pressurized fluids deep in the crust, and then transported upwards on fissures and cracks where it is deposited closer to surface.
90% of gold produced today is recovered through the cyanide leaching process.
There are three distinct streams that make up supply: official sales, recycled gold, and mine production. There has been a 571% increase in gold purchases from central banks from 2011 to 2010. Since the 2008 financial crisis, more people have opted to recycle gold as well. Recycling has increased 93% from 2002 to 2011.
Gold discoveries are declining and it is becoming more expensive to find gold. Data also shows that the grade of underground and open pit gold mines are decreasing over time. . .View Full Article