What is Diamond Mining ?

Mining is a fundamental industry integral to the extraction of valuable minerals, metals, and other geological resources from the Earth's crust for various industrial, commercial, and societal purposes. This sector plays a crucial role in economic development, job creation, and technological advancements.

When and How did it appear ?

Diamonds have been valued and sought after for thousands of years due to their exceptional beauty and rarity. The appearance of diamond dates back to an unimaginable distant history - back to the times when the Earth was still an incandescent celestial body. The time needed to shape diamond has not been precisely established, but is estimated that the process may have lasted even several billion years.

Natural diamond comes as a result of carbon being transformed from a gas into a liquid state at high temperatures and under enormous pressure, and then crystallized by cooling. According to scientific measurements, diamonds appear in extreme conditions when the pressure reaches over 70,000 kg/cm, and the heat ranges from 1000 °C to 1300°C, which corresponds to conditions in the depths of around 150-250 km below the Earth's surface.

Processing of Ore to Extract Rough Diamonds

• Stage 1 - Crushing :

Once the diamond bearing ore and gravel is collected, it is transported to a primary crusher. The primary crusher is responsible for reducing the size of the ore into smaller, more manageable pieces or chucks measuring no larger than 150mm. A secondary crusher, known as a roll-crusher, may also be used to reduce the size of the ore even further.

• Stage 2 - Scrubbing :

In this stage, the ore are scrubbed to remove loose excess material and is screened. Material smaller than 1.5mm is discarded because it is too costly to extract diamonds from such a small piece of ore.

   



• Stage 3 - Cyclonic separation plant :

During this stage the diamond bearing ore is mixed with a solution of ferrosilicon powder and water, which is measured to a specific relative density. This solution is fed into a cyclone, which tumbles the material and forces a separation. Materials with a high density sink to the bottom, which results in a layer of diamond rich concentrate.

• Stage 4 - Recovery :

Here, the diamond rich concentrate is put through a series or processes involving magnetic susceptibility, X-ray luminescence and crystallographic laser fluorescence that are calculated based on the specific properties of diamonds. These processes are designed to separate the rough diamond from any other heavy density materials collected by the cyclonic separation plant. For example, diamond's fluorescence when exposed to an X-ray. Sensors detect flashes of light emitted by the diamond and send a signal to a microprocessor that fires a blast of air at the diamond, which spits it into a collection box.

• Stage 5 - Cleaned, weighed and packaged :

The diamonds collected in the recovery process are cleaned in an acid solution, washed, weighed and packaged in sealed containers for transport. In accordance with the Kimberley process, these containers are sealed with a tamper resistant seal, numbered on site, and a certificate of origin is issued.

Diamond Producing Countries :

Producing countries are countries where diamonds are found and mined. There are two major bands around planet Earth, the northern band and the southern band. A third center band also has diamonds but of lower quantity and value. The Northern band includes Russia and Canada, two of the leading diamond-producing countries. The Southern band includes Southern African states such as Botswana, South Africa and Namibia, as well as Australia. The center band includes the Ivory Coast and Sierra Leone in Africa, and Venezuela and Brazil in South America. The top five producing countries by volume of production are Russia, Botswana, the Democratic Republic of Congo (DRC), Australia and Canada.

Diamond Mining in Russia

The Mir mine also called the Mirny mine, is an open pit diamond mine located in Mirny, Sakha Republic, in the Siberian region of eastern Russia. The mine is 525 metres deep (1722.44 feet) and has a diameter of 1,200 m (3,900 ft). The Mir mine was the first developed and the largest diamond mine in the Soviet Union. Its surface operation lasted 44 years, finally closing in June 2001. After the collapse of the USSR, in the 1990s, the mine was operated by the Sakha diamond company, which reported annual profits in excess of $600 million from diamond sales. Later, the mine was operated by Alrosa, the largest diamond producing company in Russia, and employed 3,600 workers. However, in 1970s construction of a network of tunnels for underground diamond recovery began.

By 1999, the project operated exclusively as an underground mine. In order to stabilize the abandoned surface main pit, its bottom was covered by a rubble layer 45 metres thick. After underground operations began, the project had a mine life estimate of 27 years, based on a drilling exploration program to a depth of 1,220 meters. In the 1960's the mine was producing 10,000,000 carats (2,000 kg) of diamond per year, of which a relatively high fraction (20%) were of gem quality. The upper layers of the mine (down to 340 metres) had very high diamond content of 4 carats (0.80 g) per tonne of ore, with the relatively high ratio of gems to industrial stones. The yield decreased to about 2 carats (0.40 g) per tonne and the production rate slowed to 2,000,000 carats (400 kg) per year near the pit bottom.

Diamond Mining in Botswana

The Jwaneng diamond mine is the richest diamond mine in the world and is located in south-central Botswana about 120 kilometers (75 mi) west of the city of Gaborone, in the Naledi river valley of the Kalahari. Jwaneng is owned by Debswana, a partnership between the De Beers company and the government of Botswana. It is the second newest of four mines operated by the company, having begun operations in 1982. Jwaneng is an open pit mine. The mine produces 9.3 million tons per year of ore and an additional 37 million tons per year of waste rock. The mine is located on three kimberlite pipes that converge near the surface, covering 520,000 square metres at ground level.

Currently, the mine produces approximately 11 million carats (2,200 kg) of diamonds. The recoverable ore grade at the mine is about 1.25 carats per ton (250 mg/t). As of 2005, known reserves will allow production at current levels to continue for 27 years. The high rate of diamond extraction, combined with high quality diamonds fetching excellent per weight prices, make the Jwaneng diamond mine the richest diamond mine in the world by value of recovered diamonds. Jwaneng employs over 2,100 people. At the center of the diamond mine, a series of concentric circles cut deeper and deeper into the ground. Surrounding the pit is a network of roads and structures related to the mining operation.

Diamond Mining in India

Diamond mining in India extends back into antiquity. From ancient times, India was the source of nearly all the world's known diamonds, and until the discovery of diamonds in Brazil in 1726, India was the only place where diamonds were mined. India has not been a major diamond-producing country since the 1700's, but diamond mining continues. In 2013, India mined 37,515 carats of diamonds, from one industrial-scale mine and many artisanal mines; this was less than one-tenth of one percent of the world production of 132.9 million carats.

Recent Mining in Patna Region (Bundelkhand):

As of 2017, there was one industrial-scale diamond mine in India, the Majhgawan mine, near the town of Panna, Madhya Pradesh. The deposit is in a kimberlite or lamproite pipe 6.5 ha in area, and yields 10 carats to the ton. Mining is done by an open pit, which was 85 m deep as of 2011. Exploration drilling has established that the pipe continues down to at least 330 m. The mine is owned by the National Mineral Development Corporation (NMDC), employs 199 people, and has a productive capacity of 84,000 carats per year. The mine began regular production in 1967, and to date, has yielded slightly more than a million carats of diamonds. There are also numerous artisanal-scale mines. In the Panna mining district, the Madhya Pradesh government leases 8x8m plots to individuals, who wash the gravel for diamonds.

All diamonds found are required to be handed over to the government diamond office in Panna, which markets the gems, and gives the sales proceeds to the finders, less taxes and 11.5 percent royalty. In 2016, there were officially 952 artisanal mines, which yielded 835 carats of diamonds. However, there is an unknown number of small illegal mines, and an unknown amount of diamonds sold on the black market. The Rio Tinto Group discovered the Bunder diamond deposit in 2004 in Chhatarpur district near Buxwaha. The deposit is in an ecologically sensitive area. In February 2017, Rio Tinto quit work on the project, and gave the deposit and all on-site equipment to the state government of Madya Pradesh.

Uses of Diamond :

When people think of diamonds, they tend to think of jewelry, such as rings, earrings, or necklaces. However, as the hardest naturally occurring substance on the planet, diamonds are used for many other unknown purposes.

Speaker Domes : Diamonds are believed to actually enhance the performance of high quality speakers. Because diamonds are a very stiff material, they can vibrate rapidly when made into a thin dome without the deformation that can degrade sound quality.

Antidote for Poison/Disease : While there is no scientific evidence backing this usage, diamonds are often used as antidotes in various places for poisons or diseases. The belief that swallowing diamonds would ward off illness stems from the days of the plague.

Abrasives : Because diamonds are so hard and durable, they are ideal for grinding, cutting, drilling, and polishing. When used as an abrasive, very small pieces of diamond are embedded into grinding wheels, saw blades, or drill bits.

Heat Sinks : A heat sink is a passive component in an electronic system that cools a device by dissipating heat into the surrounding air. Diamonds have very high thermal conductivity, which means they are excellent heat conductors. Because of this, diamonds are used as a material for heat sinks.

Engraving : Diamonds are used for the engraving of stones made of granite, quartz, and other very hard materials. Because diamonds will not break or even scratch against the surfaces of other tough stones, using them for engraving is quite practical as the work can be completed without having to worry about replacing the engraving bit.

Potential Future Uses : In the future, diamonds may be used for surgical tools, medical devices, and prosthetic human joints. Research is being conducted into whether or not the Earth's hardest naturally occurring substance could be of any use to the medical community.