Updated 04:15 AM,Aug 21,2023
How Diamonds Are Extracted from Rocks
Several stages are involved in extracting diamonds from rocks, with the key steps outlined below:
Crushing
Since kimberlite—a relatively hard rock resembling granite—forms underground, the first step in locating diamonds is crushing kimberlite ore to uncover the diamonds trapped within. This must be done carefully to avoid damaging or breaking the diamonds. Some mines may skip the crushing stage entirely if diamonds are found in sand, soil, or fine gravel.[1]
Crushing is a multi-stage process that gradually reduces rocks into smaller fragments and recycles larger pieces until all material reaches the appropriate size for processing. It begins with rock liberation, where engineers must carefully design blasts to produce fragments small enough to be transported by truck to the primary crusher.[1]
Next, secondary crushing takes place using jaw crushers, named for their resemblance to the human jaw. These crushers bite into the rock and pass it through a narrow opening. Notably, this process generates significant dust and debris, requiring multiple washing and screening stages to recover raw diamonds—making it water-intensive.[1]
Refining (Polishing)
At this stage, raw diamonds are polished to remove unwanted impurities, followed by sieving. Materials smaller than 1.5 mm are discarded, as extracting diamonds from such tiny fragments is extremely costly.[2]
Separation by Slurry Mixing
In this phase, raw material containing diamonds is mixed with a silicon carbide powder and water solution, adjusted to a specific relative density. The mixture is then placed in a mixing truck, which agitates the material to separate components. High-density materials sink to the bottom, forming a concentrated layer rich in diamonds.[2]
Diamond Extraction and Separation
At this stage, the diamond-rich layer collected at the bottom of the mixing truck undergoes a series of processes to isolate raw diamonds from other high-density materials potentially captured during mixing. These processes include magnetic properties, luminescence under X-rays, and fluorescence or spark emission when exposed to a crystal laser, each based on the unique characteristics of diamonds.[3]
For example, diamonds emit visible light when exposed to X-rays. Specialized sensors detect these flashes and send signals to a precision processor, which triggers a burst of air to blow diamond fragments into a designated collection box.[3]
References
- ^ a b c Ehud Arye Laniado (March 30, 2016), "Diamond Recovery Methods", All Diamond, Retrieved January 24, 2022. Edited.
- ^ a b "DIAMOND MINING", Capetown Diamond Museum, Retrieved January 24, 2022. Edited.
- ^ a b "THE DIAMOND MINING LIFE CYCLE", Mining for Schools, Retrieved January 24, 2022. Edited.
