WorldWide Drilling Resource

WorldWide Drilling Resource ® 7 MAY 2018 Diamond is an extraordinary mineral with extreme hardness and inherent beauty sought after for personal adornment and industrial use. Diamonds form at high temperatures and pressures in earth's mantle about 100 miles below the surface. Deep-source volcanic eruptions begin in the mantle, and as they progress upward, they tear out pieces of mantle rock which have diamonds embedded in them. Without melting during the eruption, the pieces of mantle rock and diamonds are pushed to the surface where they can then be mined. The largest gem-quality diamond ever found is the beautiful Cullinan diamond. In 1905, at the Premier Mine in Pretoria, South Africa, the 3106-carat diamond was discovered during a routine inspection by the mine’s super- intendent. It has since been cut into nine large stones and about 100 smaller ones. Fewer than 30% of diamond mines are underground. In an open-pit diamond mine, annual diamond production may range from several thousand carats to a few million carats. From 1981-1991, the Finsch mine in South Africa, produced around 5 million carats annually, whereas annual diamond production for the extremely rich Argyle mine in Australia, reached a record 39 million carats during the height of op- eration. The worldwide demand for industrial diamonds exceeds the supply obtained through mining, so synthetic diamonds are being produced to meet this industrial demand. Diamonds are the hardest known substance and can cut through any material. For this reason, they are used in cutting and grinding applications, as well as an abrasive in numerous applications. Industrial diamonds are embedded in large steel drill bits used to drill for water, oil, and natural gas, and are also important in the manufacturing of machinery for drilling. Diamond windows are made from thin diamond membranes and are used to cover openings in lasers, x-ray machines, and vacuum chambers. These windows are transparent, durable, and resistant to heat and abrasion. Diamond speaker domes enhance the performance of high-quality speakers. Since diamond has the highest thermal conductivity of any material, it is also used to conduct heat away from the heat-sensitive parts of high-performance microelectronics. Low-friction microbearings are needed in tiny mechanical devices. Some watches have jewel bearings in their movements, and diamonds are used where extreme abrasion resistance and durability is needed. Wear-resistant parts can be produced by coating surfaces with a thin coating of diamond. In this process, diamond is converted into a vapor and deposited on the surface of parts which are prone to wear. The World of Minerals The rough Cullinan Diamond and one of the nine stones it was cut into. G&O