Diamond mining production

This discovery was significant because the pipes were not kimberlite, but a different type of volcanic rock called lamproite. One of the most productive diamond mines in the world, the Argyle mine with an ore that produces 400 carats of diamond per 100 tons, is a lamproite pipe. Albeit, the diamond is small and 90% is industrial grade. 

The worldwide production of natural diamond has risen steadily since World War II, in answer to increasing demand (mostly for gemstones) and as a result of improved prospecting and mining techniques and the opening of new mines. Production, which was only two tons in 1947, reached an estimated twenty tons in 1992. 

World annual production of natural diamonds, the cubic form of carbon, is about 110 million carats (1 carat = 200 mg). Almost all is derived from kimberlite or its weathered remnants, but Australian production is from the Argyle mine, at which the host rock is lamproite. Kimberlites are olivine- and volatUe-rich potassic ultrabasic rocks of variable geological age that typically form near-vertical carrot-shaped pipes intmded into Archean cratons. The volatile-rich component is predominantly CO2 in the carbonate minerals calcite and dolomite, and the texture is characteristically inequigranular, with large grains (macrocrysts), usually of olivine [Mg2Si04], in a fine-grained, olivine-rich matrix. 

The mining of natural raw diamonds currently accounts for 29% of diamond production quantitywise, but this small quantity accounts for 92% of the value of raw diamonds (see Table 5.7-1). 

A diamond bearing kimberlite pipe was discovered in Siberia in 1954. There are at least 300 kimberlite pipes in Siberia. The most productive of these is the Udachnaya mine near the town of Udachnaya. 

Individual chemicals may be so prepared or mixed to be suitable for use as either deflagrating or detonating explosives. Explosives find wide use as mining and constmction to blast ore, coal, and rock in petroleum prospecting and oil well production in manufacturing to bond metals and manufacture diamonds as pyrotechnics and in the aerospace Industry. Military explosives are used in demolition, ammunition, pyrotechnics, signals, and the like. 

Cyclic nitramines such as RDX or cyclotetra-methylenetetranitramine (HMX) are widely used in military composites such as Composition B (TNT and RDX) and Composition C-4 (US) or PE-4 (British) and in commercial blasting explosives such as Semtex (a Czech-made mining explosive). HMX is present as a by-product in RDX made by the Bach-mann process and has applications in explosives to be used in high-temperature environments. Chemical tests for RDX include the J-Acid and thymol tests. A number of TLC systems for RDX and HMX have been reported. With adequate sample, IR identification of the pure material in a micro-potassium bromide pellet is simple. If a diamond anvil sample holder or microscope attachment is available, excellent spectra of pure samples of milligram size or even of single crystals are easily obtained. When HMX is observed in RDX-based explosives, its concentration may suggest the national origin of the explosive. 

The town was for a long time the world center for the winning of diamonds and trading in the valuable precious stones. On top of the famous mine Big Hole , a yellow ground was found, which was a weathering product of the underlying kimberlite, called the blue ground. The mine was worked from 1871 to 1908 with simple methods, but in spite of that a depth of 1070 m was reached. In aU 14.5 million carats of diamond (2900 kg) were obtained. For this extraction a rock quantity of about 24 million tonnes of kimberlite had to be broken. 

Diamond size is expressed in carats 1 carat = 0.2 g. The mines at Kimberley have produced a total of more than 200 million carats since the 1870s. Almost half of South Africa s diamonds are of gem quality. The largest producer of gemstone diamonds in southern Africa - and in the world - however is Botswana. The world production of natural diamond in the year 2001 is shown in Table 39.3 [39.6]. 

Industrial demand for diamond is met in part by synthetic diamonds. The scale of production of synthetic diamonds is significantly greater than that of mining natural material. 

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