Gold is obtained by two principal mining methods; placer and vein mining, and also as a by product of the mining of other metals. Placer mining is used when the metal is found in unconsolidated deposits of sand and gravel from which gold can be easily separated due to its high density.

How long does it take to extract gold?

On average, it takes between 10-20 years before a gold mine is even ready to produce material that can be refined.

How is cyanide used in gold extraction?

A sodium cyanide solution is commonly used to leach gold from ore. The cyanide dissolves the gold from the ore into the solution as it trickles through the heap. The pad collects the now metal-impregnated solution which is stripped of gold and resprayed on the heap until the ore is depleted.

How does the process of extracting gold work?

How Gold Works. Removing the gold-bearing rock from the ground is just the first step. To isolate pure gold, mining companies use a complex extraction process. The first step in this process is breaking down large chunks of rock into smaller pieces. At a mill, large machines known as crushers reduce the ore to pieces no larger than road gravel.

Why is gold considered to be so valuable?

It is fairly easy to process and as far as ancient people were concerned it was indestructible it does not tarnish like silver or copper. It does not dissolve in normal acids and solvents. It is pretty and if you alloy it with other metals it can have a variety of colours.

What kind of solvent is used to extract gold?

The most common solvent is cyanide, which must be combined with oxygen in a process known as carbon-in-pulp. As the cyanide and oxygen react chemically, gold in the pulp dissolves. When workers introduce small carbon grains to the tank, the gold adheres to the carbon. Filtering the pulp through screens separates the gold-bearing carbon.

Why are silver and gold so rare in the world?

With all the noble metals except silver and gold, you have the opposite problem. They are so rare that you would have to cast some very tiny coins, which you might easily lose. They are also very hard to extract. The melting point of platinum is 1,768C. That leaves just two elements – silver and gold. Both are scarce but not impossibly rare.