Have you ever pondered on the process of transforming raw gold from an “underground rock” into pure gold? While this may seem like classified information only reserved for chemists, the process is not too difficult to wrap your head around. Below we take you through the steps of finding and refining raw gold.
Finding the Deposits
It should come as no surprise that the first step is finding the deposits of raw gold. Geologists achieve this by studying special maps to identify areas with the potential to produce gold deposits. Additionally, they look for natural formations and study rocks to determine the possibility of finding gold underground. Most gold in Australia today, for instance, is very fine-grained and hardly seen in rocks.
After finding a promising area, geologists conduct tests to confirm their suspicions regarding the presence of gold. Some of their testing techniques entail geophysics, remote sensing and geochemistry.
In this step, geologists obtain rock samples via drilling. They take these samples for further analysis to determine the presence of gold in prospective locations. Some of the tests they conduct also provide meaningful information regarding the quality of the gold present. This information helps determine whether mining the site is a worthwhile venture.
Determining the Nature of the Mine
If the tests confirm the presence of high-quality gold, mining engineers will be involved to determine the most practical type of mine given the location. They will also have to develop methods of handling any possible physical obstacles before the actual mining begins.
It is possible to assume that mining should commence immediately at this point. However, this could not be further from the truth. At this juncture, there is still plenty of preparation that needs to happen before operations commence. Workers need to build the necessary supporting infrastructure, e.g., roads, processing and storage facilities before operations begin. This usually takes between one to five years.
Testing More Samples
After site preparation is complete, workers will have to take samples for further testing. These tests are essential for determining the gold deposits’ exact metallurgic qualities. Results from the tests help miners decide on the best mining techniques for the site.
Even after extracting gold from beneath the earth’s surface, it is still raw ore that needs processing to become pure gold. Miners crush the gold ore at the on-site processing facility before taking it through a series of processes that vary based on the minerals and elements mixed with the raw gold.
On-site processing helps separate raw gold from unwanted elements. How complex the process will be largely depends on the grade of the gold ore. For instance, the procedures involved in processing low-grade gold ore are relatively simple compared to the more complex and extensive processes needed for high-grade ore.
After completing the initial on-site processing, miners transport the semi-processed gold to off-site refineries for further refining. Australia has various smaller refineries but the market is dominated by the biggest two refineries, ABC Refinery and Perth’s Mint, in fact these two companies are so dominant that it isn’t uncommon for employees to leave one for the other.
The purpose of off-site refining is to expel any remaining impurities from the gold. Off-site refineries achieve this by melting the crude gold then treating it with chloride. Chloride combines with any unwanted minerals or elements and naturally separates from the gold. Refiners expect the gold to be at least 99.5% pure after this process.
The last step of refining is casting the gold into anodes or electrodes and placing them in electrolytic cells. An electric current is then passed through the electrolytic cell to make the gold 99.99% pure.
The Final Result
After the highly involving and enormously complicated processes, we finally end up with pure gold that various industries can process further into different gold products. While the process of finding and refining gold is lengthy and complex, it is definitely not ambiguous.