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Gold Mining: Know the Journey of Gold from the Start

Neil Valentine D'Silva Apr 19, 2019
This write-up is about the real metal gold, and the processes that are used in mining it.
Gold is a largely nonreactive metal, and for that reason it is found in the Earth's crust almost in a pure state. It is obtained in the bedrock that is found in the Earth's crust. Though it is found in its virtually pure state, it is a challenge to find out where it is present and to extricate it from the Earth.
There are many methods that are used for removing gold from the crust onto the Earth. The crudest method and even the most common is the gold scanning technique. Of course, a method like scanning after adding water to its earthy mixture cannot be implemented on an industrial scale.
Industrial methods are usually implemented for the metal that is deeply embedded in the rock of the Earth. An example of this is the open pit method, which is described here:

✶ First, using various techniques the presence of the precious metal is ascertained. For this, methods such as using metal detectors or taking satellite images are employed.
✶ Once the images are taken, high precision computers are used to ascertain at what depth and in what quantity the gold is present. This is important for ordering the right kind of equipment.

✶ It is also important to take all necessary governmental permissions at this point.
✶ Then the mechanical process begins. In this, a heavy vehicle with a drill fitted on it is driven to the spot. This drill is made vertical by a motorized machinery attached to the truck, and a hole is bored.
✶ The preliminary ore is extracted and is sent to the labs for checking its quality and also to ascertain whether mining at that spot will be indeed a profitable activity.

✶ Once that is done, several more trucks are driven to the spot, all with drills on them.
✶ If the gold obtained is of high quality, then it is sent to a mill where it is ground to powder. From there, if needed, it is purified by roasting up to 1,000 degrees Fahrenheit with carbon, or cyanide processing, or is oxidized in an autoclave with sulfide.

✶ The cyanide processing is the most significant processing step.

Cyanide Processing

Cyanide processing is used in gold mining when the gold obtained is of an inferior quality. Due to the very precious nature of this metal, it needs to be purified to a very high grade. This is where the method of cyanide processing becomes important. Take a look at how it is done.
✶ The mined precious metal of the inferior quality is broken into small pieces and then kept on a pad that has grooves in it to place the pieces.

✶ Then a dilute solution of cyanide is introduced onto this pad.

✶ The cyanide will dissolve the metal in it. This solution is collected. It contains the pure gold.
✶ This solution is passed over activated charcoal. The gold pieces will get adsorbed onto the activated charcoal, and that can be separated through further processes.

✶ The gold is either physically stripped from the carbon, or extracted as a precipitate obtained after an electrolytic procedure.
The pure gold which is obtained after all these processes is then cast into small bars. These bars are further processed in refineries to get 90% pureness.