The story of precious diamonds: how are diamonds mined and processed?

 

Discover how diamonds are mined, what the various diamond mining techniques are, and how diamonds are recovered from the rough ore. After hundreds of years of scientific advancements, mining has now become an incredibly skilled process, enabling the diamond miner to extract precious stones without risks of damaging them.

Learn about the many KGK mining techniques and the processes used to extract diamonds from the raw material. Diamond mining has evolved into a highly sophisticated procedure over the course of hundreds of years, allowing the miner to safely harvest precious stones.

 

Processes involved in the mining of diamonds

A KGK diamond's story begins with an unpolished stone brought directly from the mine. Even in its unfinished state, it shows promise, its massive size merely a hint at what it could become. The diamond's entire potential is only unlocked by a skilled artisan. After being carefully picked for its individual qualities, each raw diamond must be cut and polished to reveal its full potential for brilliance.

 Almost all of the world's gem-quality diamonds are mined in Southern Africa. Diamonds are mined at a rate of over 13 million carats per year, with a total value of nearly $9 billion USD.

 The three most common approaches to KGK mining are:

1. ·         Pipe mining (primary deposits) consisting of open-pit mining and underground mining;
2. ·         Alluvial mining (secondary deposits);
3. ·         Marine mining

Pipe mining

There are two types of pipe mining: open-pit mining and underground mining.

Open-pit mining

With open-pit mining techniques like the one used at the Kimberley Big Hole, the sand and rock layers covering the Kimberlite are first excavated. Blasting is used to further dismantle the ore in the pit. After the ore is shattered, it is placed onto a truck and taken to a primary ore crusher, where the process of removing the diamonds begins.

Underground mining

In order to get to the kimberlite pipe, miners have to bore deep into the planet. The tunnels are built one on top of the other, with a funnel connecting the two. When blasting ore from the upper level, it will descend down the funnels and accumulate in the second tunnel below. Loaders come here to gather the fragmented ore and transport it back to the surface for further processing.

Alluvial mining

The Kimberlite pipe that reaches the surface of the Earth is worn by wind and rain over thousands of years. Rivers and streams carry Kimberlite's rough diamonds to the ocean. Diamonds like this are frequently unearthed in the sand and gravel layer of other substances including mud, clay, and marine vegetation. The Industrial Alluvial Process entails constructing a massive wall to concentrate the flow of water to a single location, from which the gravel may be extracted and transported to the surface for further processing.

Marine mining

To get diamonds, KGK groups’ marine miners have to go to extreme depths, to the seafloor. When searching for diamonds at sea, specialised ships utilise powerful crawlers to suction gravel from the seafloor and transport it to the surface through a network of pipelines and hoses. Swimmers used to mine for diamonds by collecting gravel from the seafloor.

Diamonds can also be extracted by means of a large-scale drill that is attached to the ship.

Approximately 64% of Namibia's total diamond production comes from marine diamond deposits, the majority of which are located around the coast of Namibia.

The process of ore to extract rough diamonds

Diamond extraction occurs in 5 distinct steps:

Stage 1: Crushing

Collecting and transporting the diamond-bearing ore and gravel to a primary crusher, which reduces the ore to bits no larger than 150mm, makes the process much more manageable. In some cases, the ore is further reduced in size by passing it through a secondary crusher (sometimes referred to as a roll-crusher).

Stage 2: Scrubbing

The ore pieces are cleaned to eliminate any surplus material and are then screened in the screening stage. It is not cost-effective to extract diamonds from ore fragments smaller than 1.5 mm, thus these are abandoned.

Stage 3: Cyclonic Separation Plant

The diamond ore is combined with a solution made from a specified concentration of ferrosilicon powder and water. After the solution has been combined, it is put into a cyclone and tumbled to push the components to separate. Materials having the highest density fall to the cyclone's base, creating a stratum rich in diamond concentrate.

Stage 4: Recovery

The diamond rich concentrate undergoes several procedures that test its magnetic susceptibility, x-ray luminescence, and crystallographic laser fluorescence. Diamond's distinctive characteristics are used in the calculations for these procedures. These steps are necessary to isolate the rough diamonds from the other heavy density materials that were gathered in the cyclone separation facility. Sensors pick up on the brief bursts of light that diamonds give off. The action triggers a microprocessor to release a stream of air toward the diamond. The gem is then spat into a donation jar.

Stage 5: Cleaned, Weighed and Packaged

The diamonds from the collection box are washed with acid, weighed, and then packaged for shipping. Using the Kimberley process, each box is given a unique number and sealed with a tamper-proof seal.