What are the different ways that gold’s mined, what happens once it’s extracted, how does it go from ore to a form where it can be used as a useful storage of wealth?
Gold has a long history – some of the oldest golden artifacts discovered date back to earlier than 4000 BC. For nearly 6,000 years humans have used gold to demonstrate their prosperity. In troubled times people often used it as a way to protect their wealth. It has long been used for trading and eventually became currency, cementing its role in everyday life. Even early civilisations used standards for purity and weight to protect value in gold.
Mankind has long been attracted to gold’s entrancing properties, so getting it out of the ground has been a skill that has been developed over thousands of years.
How is gold mined?
Gold mining takes place all over the world, on every continent apart from Antarctica.
In the past 10 years global annual gold mine production has been 2,700 tonnes on average. In recent years, this has risen to more than 3,000 tonnes. Although the World Gold Council advises that this trend is unlikely continue.
So what are the different ways of mining?
1. Placer mining: this is mining in a stream bed for gold deposits. Placer mining takes advantage of gold’s high density, which causes it to sink away from the minerals with which it’s found. Place mining includes old fashioned techniques like panning for gold in streams, as well as more modern techniques, such as sluicing, where a ditch cut in hard gravel or rock is used to channel a stream of water and gold-bearing gravel is carried. Rivets placed along the bottom of the sluice cause the water to whirlpool into small basins, slowing the current so that gold can settle and can be discovered.
2. Hard rock mining: this is how the majority of the world’s gold is mined. It’s the process of using open pit or underground mining tunnels to recover gold straight from the rock where it was once formed. An example of this type of mining is South Deep in Johannesburg, South Africa. It’s reportedly recovered 81.5M oz of gold to date and is expected to continue production until 2080.
3. By-product mining: just as the name sounds, this is where the primary goal of the mine wasn’t to recover gold, but other resources such as copper, sand and gravel. The largest mine of this kind is Grasberg in Papa, Indonesia, which was originally developed for extracting copper and was found to contain more than 100M oz of gold.
4. Processing gold ore is finely crushed rock or earth that contains trace gold, which is then extracted using chemical processes.
Does gold only come from mines?
There is also a large secondary source of gold: the recycled gold market. This is gold that has been previously refined and can come from a variety of sources, including high-value sources like jewellery and catalytic converters and circuit boards. It’s also far more environmentally friendly than mining for new gold.
Recycled gold accounts for about 1/3 of the total supply, according to the World Gold Council
What happens once it’s extracted?
Once the gold is extracted from the mine or from a secondary source, it can then be refined to separate it from any impurities. The higher the refinement, the finer the gold. The fineness of gold refers to the ratio by weight of the primary metal to any added base metals or impurities. This fineness is generally rounded to a three-figure number. For example, a fine gold piece which contains 99.9 percent gold would be labelled 999 or .999. All Royal Mint Refinery gold bars (RMR gold bars) meet this high standard.
All Royal Mint Refinery silver and gold bullion is sourced from London Bullion Market Association Good Delivery approved sources.
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