Sunday, August 9, 2009

Diamonds in China - 701 Changma diamond mine

Diamonds in China - 701 Changma diamond mine

Many people don't know that China has diamond mine and for quite a long time as China's 701 Changma diamond mine was opened in 1975. China has produced about 300,000 carats in 2002 and their diamond industry looks to be having great potential despite some problems.701 Changma diamond mine is the largest producer of diamonds in China and is located in the Shandong province.

In its more than 30 years of existence this diamond mine produced over 1 Mct of quality diamonds.Some other provinces are also being explored beside Shandong province (Liaoning, Anhui, Jiangsu and Shaanxi Provinces) as China is well aware of high profits in diamond business and wants to become major player on diamond market.Production in Changma diamond mine increased significantly in last couple of years and considering the findings of new kimberlite pipes in some provinces China is on the right way to become major diamond force in years to come.

Not only China is the large diamond producer but is also among top five consumers of diamond jewelry with and this is increasing because of China's rapid economic growth.Despite China's great potential in diamond industry, China is still not complete certainty for profits in diamond business, since excessive management, external costs, corruption and lack of reliability prevented China's full diamond industry development.

There's also influential underground economy, but with the wise government policy China could and really should benefit from its big potential, as both producer and consumer of diamonds.

Diamonds in South Africa - Venetia diamond mine

South Africa has its first diamonds discovered in 1867, when diamonds were discovered near Kimberley. and this rich diamond source secured South Africa's number one spot as the world's leading diamonds producer in the mid-twentieth century.

Famous De Beers company was also founded in Kimberley (known also as "Diamond city") as Cecil Rhodes founded this well known company in 1888. De Beers is still the most influential diamond force in South Africa.

In 2003 South Africa produced above 11 Mct of diamonds. the most important mine is Venetia Diamond mine in the Limpopo province in South Africa, which is famous for producing some of the best quality diamonds in the world since its opening in 1992. Venetia Diamond mine alone produced in 2005 almost 7,2 Mct of diamonds and it employs about 1000 people. This is also first mine in the world to achieve ISO 9002 quality management certification. This is open-pit mine that is expected to carry on for the next 20 years.

South Africa is also home of prestigious Diamond Education College which provides internationally recognized diplomas and trains its students in rough and polished diamond evaluation and rough diamond marking.

Diamonds in Russia - Sakha Republic diamonds

Russia is world's second largest producer of diamonds just behind Botswana and accounts for about 21% of global diamonds produced. When speaking about Russian diamonds, three regions take special place: the Arkhangelsk region, Perm region and the Sakha/Yakutsk Republic. Most diamonds are mined in Sakha Respublikata in Yakut (Yakutia) of Siberia, just below the Arctic circle.

Yakutsk is the capital city of the Sakha Republic (Yakutia) and this area is not only filled with diamonds but also with gold and oil. Sakha Republic is place where major Russian producers operate large open-pit mines on the Udachnaya and Jubilee kimberlite pipes.

Udachnaya mine ("udachnaya" meaning lucky) is the largest diamond deposit in Russia and has produced very high quantity of big diamonds (for instance a 301 ct diamond was recovered in August 2003). This mine is also producing by number of experts, world's clearest diamonds.

Jubilee mine started its work in 1986 and it is open pit mine just as Udachnaya mine. This mine is constructed over the 'Yubileinaya' kimberlite pipe.

Anabar mine is also located in Sakha Republic but harsh weather conditions (most northern of all Russian mines) cause this mine to operate just during the short summer season.

Siberia certainly holds many more diamond deposits which just wait to be discovered so Russia's diamond future looks to be very bright and Russia has even potential (considering huge area this country covers) to overtake number one spot from Botswana in years to come.

Red diamonds - Rarest of them all

Among fancy colored diamonds red diamonds have special place, not only because these these diamonds are among most desirable diamonds, but also because they are extremely rare, so rare that many jewelers have never seen one of this really unique diamonds. Out of all colored diamonds red diamonds are the rarest of them all.

When saying extremely rare that doesn't only apply to natural red diamonds as it is also very difficult to find even enhanced red diamonds, so you can imagine how precious red diamonds really are. So even if you have plenty of money finding natural red diamond will be more than difficult.

Natural red diamonds are mostly found at Argyle mine in Australia, though in very limited number which has tremendous impact on their price which is in most cases astronomical. The biggest red diamond ever found is known under the name of "Red Shield" and has only 5,11 carats which is more than hundred times less than largest diamonds of any kind. Another famous red diamond was "Hancock Red" that for its weight of 0,95 carats was sold for incredible price of $880,000 at Christie's New York in April, 1987.

Red diamonds are really elite among fancy colored diamonds, and only few lucky (and extremely wealthy) people have luck to buy these unique diamonds. Many other are forced to look for alternatives in different color, or rubies which are much more affordable.

Diamonds in Brazil - Long history of diamonds

Brazil is the second country (after India) in which diamonds were found (that happened in 1725). In these early years Brazil was still very much behind India, but as the Indian diamonds dried up, Brazil took the first place throughout the 19th century leading the world diamond production till 1870.

The most famous diamond found in Brazil is "Star of the South," a 254 carat stone that was found in 1854. Brazilian diamonds occur usually in alluvial deposits that were created by Diamantiferous sands and gravel called "cascalho" or "cascalhão".

Brazilian diamond industry is mostly connected with these two states: Matto Grosso and Bahia and these two diamond rich states should also provide future diamond findings as Brazilian diamond industry still looks very strong despite relatively early discovery of diamonds.

Brazil's currently holding 10th place in the world with total annual production in 2005 of about 700,000 carats.

Friday, August 7, 2009

Diamond Geology

Diamond Geology

Kimberlite Pipes

Diamonds form at a depth greater than 93 miles (150 kilometers) beneath the earth's surface. After their formation, diamonds are carried to the surface of the earth by volcanic activity. A mixture of magma (molten rock), minerals, rock fragments, and occasionally diamonds form pipes shaped like champagne flute glasses as they approach the earth's surface. These pipes are called kimberlites (see diagram below). Kimberlite pipes can lie directly underneath shallow lakes formed in the inactive volcanic calderas or craters.

Kimberlite is a diamondiferous igneous-rock matrix composed of carbonate, garnet, olivine, phlogopite, pyroxene, serpentine, and upper mantle rock, with a variety of trace minerals. Kimberlite occurs in the zone of the Earth's crust in vertical structures known as kimberlite pipes (above, right). Kimberlites are found as "dikes" and "volcanic pipes" which underlie and are the source for rare and relatively small volcanoes or "maars" (above, left). Kimberlite pipes are the most significant source of diamonds, yet only about 1 in every 200 kimberlite pipes contain gem-quality diamonds. Many kimberlite pipes also produce alluvial diamond placer deposits.

Diamond bearing kimberlite in some parts of South Africa is black in color (above, right). Most kimberlite is called "blue-ground" kimberlite (above, left) or "yellow-ground" kimberlite and can be found worldwide. The name "Kimberlite" was derived from the South African town of Kimberly where the first diamonds were found in this type of rock conglomeration (see section on "Kimberley - North Cape" below).

Lamproite Pipes

Lamproite pipes produce diamonds to a lesser extent than kimberlite pipes. Lamproite pipes are created in a similar manner to kimberlite pipes, except that boiling water and volatile compounds contained in the magma act corrosively on the overlying rock, resulting in a broader cone of eviscerated rock at the surface. This results in a martini-glass shaped diamondiferous deposit as opposed to kimberlite's champagne flute shape.

Alluvial (Placer) Diamonds

The location of alluvial (secondary or placer) diamond deposits is controlled by the surrounding topography. Alluvial diamond deposits are usually located within river terrace gravels that have been transported from their location of origin, usually from kimberlite deposits.
Diamondiferous material tends to concentrate in and around 'oxbow lakes,' which are created by abandoned river meanders. These dried 'lakes' receive river water during seasonal flooding which transports large amounts of sediment held in suspension.
The alluvial terrace gravels (below, left) and marine gravels of the south-western coastline of Africa represent the some of the world's largest placer diamond deposits. The world's largest known gem quality alluvial diamond deposits are located along the Namib Desert coastline of southwestern Africa, known as the Sperrgebiet or "forbidden territory," and along the Orange River near Alexander Bay. Namibia's placer diamond deposits are between 40 and 80 million years old, carried from their primary origination point on the Kaapvaal Craton, in central South Africa and Botswana.

Alluvial diamond mining in Angola takes place along a meandering stretch of the Cuango River flood-plain which is also along the south-western coastline of Africa. Some of the largest and highest gem-quality diamonds produced from alluvial placer diamond mining have come from this region, including Angola's two largest diamonds at 105.9k and 101.8k.
Many of these alluvial diamond deposits occur in Pleistocene and Holocene successions (1.8 million to 10,000 years ago). The diamonds within these deposits were transported from deeply-eroded diamondiferous kimberlites or, to a lesser extent, from olivine lamproites formed during the Cretaceous or Permo-Triassic period. Westward draining river systems transported these diamonds to Africa's continental coastline for final deposition within on-shore marine terrace gravels. Diamonds that were transported downstream, but were not deposited on land, made their way to the sea bed just offshore. Diamonds in marine areas are typically trapped in bedrock depressions such as gullies, potholes, depressions, channels or other trapsites for diamondiferous deposits.

Artisanal Mining

Artisanal diamond mining (aka "small-scale mining") involves nothing more that digging and sifting through mud or gravel river-bank alluvial deposits (above, right) with bare hands, shovels, or large conical sieves. Laborers who work in artisanal diamond mining are called "diamond diggers" (below left). Artisanal diamond mining is a form of "subsistence based" non-mechanized mining that is used in poorer countries throughout the world.

Artisanal diamond mining is used throughout west Africa, in conflict zones where mechanized mining is impractical and unsafe. Artisanal diamond mining accounts for 90% of Sierra Leone's diamond exports and is the country's second largest employer after subsistence farming. It is also used extensivly in Angola, the Congo (DROC), and Liberia.

Saturday, August 1, 2009

Diamond Mines of the World | Botswana

Diamond Mines of the World Botswana

Botswanan Diamond Mines

Jwaneng Diamond Mine

Jwaneng (meaning "a place of small stones") is the richest diamond mine in the world when measured by value of recovered diamonds. The Jwaneng Diamond Mine is located in south-central Botswana about 100 miles west of the city of Gaborone, in the Naledi river valley of the Kalahari Desert. The mine began operations in 1982, and is co-owned by De Beers and the Botswanan government under the name 'Debswana Diamond Company.'

Jwaneng is an open pit mine dug over three kimberlite pipes that converge near the surface. The mine has a very high extraction rate, producing 9.3 million tons of kimberlite ore per year at a ratio of 1.25 carats of diamond per ton. In 2003, the mine produced 14.3 million carats of rough, high-quality diamonds. As of 2005, known reserves will produce at current levels for 27 more years. The Jwaneng mine employs over 2,100 workers.
Jwaneng is the first Botswanan to receive ISO 14001 certification for environmental compliance and has maintained a 5 star NOSA safety rating since 1986. The mine has won multiple national and international safety awards since its inception.
Botswana is a relatively wealthy African country, and has had one of the fastest per-capita income growth rates in the world. Botswana gained its independence in 1966 and has had strong ties to the economy of South Africa for several decades. Botswana's history of diamond mining is commemorated on the 20 and 100 Pula bank notes (below).
There are three additional diamond mines of significance in Botswana. The Lethakane Mine ("little reeds") open pit mine is the second oldest of Botswana's four mines. The Orapa Mine ("resting place for lions") open-pit mine is the oldest of Botswana's mines, located along the 'Orapa Kimberlite Track,' near the boarder with Zimbabwe. The Damtshaa Mine ("water for a tortoise") open pit mine is the other significant mine in Botswana.

AK6 Diamond Mine
De Beers is expecting to have Botswana's first new diamond mine in nearly 26 years, operational by 2008. The AK6 kimberlite deposit is expected to produce up to 1.5 million carats a year.