We’ve no doubt all seen the old western movies of the prospector with a pan in the river searching for gold. In early America, pioneers sunk their fortunes into searching for gold this way.
In modern times though, mining for gold is a much more intensive, yet sophisticated process. Most surface, or alluvial gold has been found, which is why gold is mainly mined from the earth today. It’s largely a matter of technology and requires much expertise and elaborate equipment.
Mining for gold today can essentially be broken down into 9 steps. Continue reading to learn more about how gold is discovered, how it’s brought out of the ground and how it’s refined to produce beautiful gold coins, bars, jewelry and other items.
Step #1 – Finding Deposits
The first step is discovering where gold deposits may be. Geologists use special ‘geology’ maps to look for promising areas to explore further. They examine physical and chemical characteristics of surface rocks to determine if any gold is in the ground beneath.
Step #2 – Analysis of Promising Areas
Once some promising areas are identified through their geological characteristics, targets for drill testing are outlined using a variety of techniques, including remote sensing, geophysics and geochemistry (…both air and ground based).
Step #3 – Drill Testing/Samples
Next, rock samples are taken through drill testing and analyzed. Geologists and mining engineers use these samples to determine if gold actually exists, the size of the deposit and the quality of gold in the ground beneath. This information is used to determine if enough gold exists under the surface to make mining worthwhile.
Step #4 – Type of mine
If it’s determined the amount and quality of deposits makes mining worthwhile, engineers will next determine the type of mine that’s needed, any physical obstacles and the impact the mine will have on the surrounding environment.
Step #5 – Building Infrastructure
Before any mining can take place, infrastructure like roads and processing facilities must be constructed. Even the simplest open-pit mines can take up to a year to construct before any mining can occur. And since many potential mines are in remote areas, entire infrastructures like roads, administrative offices, equipment storage areas and even whole towns have to be built. Much of the time, it can be up to 5 years between the times discovery is made to when actual mining takes place.
Step #6 – Mining samples and determining processing
Once mining gets underway, samples must be taken to determine the precise metallurgical qualities of the ore. This is done in order to determine the appropriate processing technique.
Step #7 – Processing (on-site)
Once ore is extracted, processing it into pure gold must be done. Ore is first crushed and then undergoes various processes depending on the nature of associated minerals. Processing low-grade ore is relatively simple while higher grades require more extensive processing.
Step #8 – Refining (off-site)
Once basic processing is done, the ore is taken to a refinery where the remaining impurities are stripped out. Crude gold is melted and treated with chloride, which converts any remaining foreign metals to chloride which will then drift off the gold. The result is 99.5% pure gold, which is then cast into electrodes (…known as anodes) where it is then placed into an electrolytic cell. A current is then passed through the cell, with the end product being 99.99% pure gold.
Step #9 – Mine reclamation
After a few years, gold reserves in the mine will be exhausted. In the old days, the mine would be boarded up and abandoned. Today though, a reclamation project is done to try and return the land to its previous natural state – as much as possible anyway.
As you can see, the process of taking metal ore from the earth and converting it to gold bullion is quite extensive and requires a lot front-end investment and time. In the end though, we get these shiny coins and bars to enjoy.
Gold miners too take special care to make the impact of mining for gold as light as possible. Reclaiming land to its previous natural state is the final and perhaps most important step to ensuring the process of obtaining gold doesn’t result in permanent damage to the landscape.