Diamond Mining Methods | Diamond Museum Cape Town

PIPE MINING

(PRIMARY DEPOSITS).

In the realm of pipe mining, two distinct methods prevail: open-pit mining and underground mining.

Unveiling the hidden treasures lying beneath the surface, open-pit mining entails the meticulous extraction of sand and rock layers that guard the precious kimberlite. With thunderous power, a resounding blast shatters around 3,000 tonnes of valuable ore, setting the stage for the next phase. Accomplished excavators deftly load the fragmented ore onto mighty haul trucks, commencing a journey towards the heart of diamond extraction. Witnessing the grandeur of open-pit mining, the Kimberley Big Hole stands as a testament to this remarkable process.

Deep within the depths of the Earth, intrepid miners venture forth to unearth the hidden treasures nestled within the kimberlite pipe. Delving into the underworld, tunnels are meticulously crafted, forming a dual-layered labyrinth, intricately connected through a network of captivating funnels. Commencing their quest on the uppermost level, miners unleash the explosive force to extract precious ore, gracefully cascading through the enchanting conduits, ultimately gathering within the depths of the second tunnel. In this subterranean chamber, diligent loaders diligently gather the fractured ore, eagerly preparing for its triumphant return to the surface, where it shall undergo a transformative process.

ALLUVIAL MINING

(SECONDARY DEPOSITS).

Through countless millennia, the kimberlite pipe that pierces the Earth’s crust undergoes a mesmerizing transformation as it is sculpted and molded by the forces of wind, rain, and the flowing currents of rivers and streams. Within the eroded kimberlite, exquisite diamonds lie hidden, embarking on a captivating journey downstream. It was amidst the alluvial deposits of South Africa where the world’s first glimmering diamonds were unearthed, forever altering the course of history.

In modern times, the process of alluvial mining has evolved into a grand endeavor where a massive barrier is constructed to corral water in a specific location. Within the depths of the gravel layer, hidden beneath layers of various elements like mud, clay, and submerged vegetation, diamonds frequently lay in wait. Once the precious gravel is aggregated, it is then transported to the surface with great effort and readied for further refinement.

MARINE MINING

Marine mining is the captivating process of extracting diamonds from the mesmerizing depths of the seabed, located hundreds of meters below the water’s surface. In ancient times, the art of marine mining consisted of brave divers venturing near the shore, diligently gathering precious diamond-bearing gravel from the shallow seabed. However, with the advancement of technology, the practice has transformed into a remarkable spectacle, involving state-of-the-art ships specially designed to venture far into the vast ocean in search of these coveted gems. These magnificent vessels employ a formidable crawler that skillfully sucks up gravel from the seabed, utilizing flexible hoses and pipes. Alternatively, a grand-scale drill mounted on the ship is employed to skillfully excavate diamonds, adding an air of awe and intrigue to the entire process.

Namibia’s coastal region stands as a treasure trove for marine diamond deposits, unrivaled in abundance, contributing a staggering 64% to the country’s overall diamond output.

PROCESSING OF ORE TO EXTRACT ROUGH DIAMONDS

The extraction of diamonds from ore involves a captivating journey through five distinctive stages.

Phase 1 – Obliterating.

After the collection of the ore and gravel containing precious diamonds, a fascinating journey begins. The precious cargo embarks on a grand adventure towards the primary crusher, where its destiny is reshaped. With sheer might, the primary crusher diligently transforms the ore into smaller, more wieldy fragments or chunks, ensuring they measure no more than 150mm. A companion in this transformative quest, the secondary crusher, affectionately known as the roll-crusher, joins forces to delicately refine the ore, pushing the boundaries of size reduction even further.

Phase Two – The Art of Purification.

During this phase, the ore undergoes a thorough scrubbing process to eliminate any superfluous matter, followed by careful screening. Any material with a size below 1.5mm is disregarded due to the high extraction costs associated with retrieving diamonds from such diminutive ore fragments.

The Enchanting Cyclonic Separation Facility of Stage 3.

In this phase, the ore containing precious diamonds is combined with a concoction of ferrosilicon powder and water, carefully calibrated to achieve a distinct relative density. The resulting mixture is then introduced into a cyclone, where it undergoes a captivating whirl, effectively segregating the components. Heavy materials, boasting remarkable density, gracefully descend to the bottom, thus giving rise to a lustrous stratum of concentrated diamonds.

Phase 4 – The Revival.

In this procedure, the concentrate containing abundant diamonds undergoes a sequence of intriguing techniques such as magnetic susceptibility, X-ray luminescence, and crystallographic laser fluorescence. These techniques are carefully devised by considering the unique characteristics of diamonds. The primary objective of these processes is to effectively segregate the raw diamond from any other materials with high density that are gathered by the cyclonic separation plant. For instance, the fluorescence of a diamond when exposed to an X-ray is utilized. Advanced sensors are employed to detect the mesmerizing bursts of light emitted by the diamond, triggering a signal to a microprocessor. This signal prompts a powerful gust of air to propel the diamond into a designated collection container.

Phase 5 – Pristine, quantified, and neatly wrapped.

After being gathered during the recovery process, the diamonds undergo a thorough cleansing in an acid solution. They are then washed, meticulously weighed, and carefully packaged in securely sealed containers, ready for transportation. Adhering to the regulations of the Kimberley process, each of these containers is tightly sealed with a tamper-proof seal, numbered on location, and an official certificate of origin is duly issued.