Letseng diamond mine
{{Short description|Diamond mine in Lesotho}}
{{EngvarB|date=August 2017}}
{{Use dmy dates|date=August 2017}}
{{Infobox mine
| name = Letšeng Diamond Mine
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| pushpin_map = Lesotho
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| coordinates = {{coord|29|0|01|S|28|51|43|E|region:LS_scale:30000|format=dms|display=inline,title}}
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| country = Lesotho
| products = diamonds
| financial year =
| type = diamond
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The Letšeng Diamond Mine, found in the landlocked Southern African kingdom of Lesotho, is owned by Gem Diamonds, Ltd. and the government of Lesotho, at an elevation of {{cvt|3100|m}} it is the world's highest diamond mine.
Production
It is characterised by extremely low grade ore (less than {{convert|2|carat|mg|disp=flip}}/hundred tons) and is known for producing huge diamonds, having the highest percentage of large diamonds (greater than {{convert|10|carat|0|disp=flip}}), giving it the highest dollar value per carat of any diamond mine. The world average is roughly US$81 per carat, while Letšeng averaged over US$1,894 per carat for the first six months of 2007.{{cite web
|url = http://www.fin24.co.za/articles/default/display_article.aspx?Nav=ns&ArticleID=1518-24_2182627
|title = Big diamond discovery in Africa
|accessdate = 13 September 2007
|date = 2007-09-13
|work = Finance 24
|publisher = Fin24.com
|doi =
|quote =
}}{{dead link|date=December 2017 |bot=InternetArchiveBot |fix-attempted=yes }}
Unusual for Africa, and due to the elevation, temperatures at the mine drop to -20 °C, and snowfalls are common in winter.
Geography
=Climate=
Letšeng has an alpine tundra climate (Köppen: ET) bordering on a dry-winter subarctic climate (Dwc). This means that Letšeng has a chilly climate with fairly cool temperatures throughout the year, even for Lesotho, and snowfalls can happen as well. The average annual temperature is {{convert|5.2|C}}, the average annual high temperature is {{convert|10.4|C}} and the average annual low temperature is {{convert|0.1|C}}. The warmest month, January, has an average temperature of {{convert|9.8|C}} and an average high temperature of {{convert|14.8|C}}. The coldest month, June, has an average temperature of {{convert|-0.1|C}} and an average low temperature of {{convert|-5.5|C}}. June is the only month with an average temperature below freezing, although the average temperature of July is exactly {{convert|0|C}}.
Letšeng has an average annual precipitation of {{convert|881|mm}}. However, like most of Lesotho and South Africa, this is not evenly distributed throughout the year. Letšeng has a wet season with abundant rainfall from October to March and a dry season with less precipitation from May to August - the coldest time of year. In terms of precipitation April and October serve as transitions between the wet and dry seasons. January is the wettest month, receiving {{convert|133|mm}} of precipitation on average, while July is the driest month, receiving only {{convert|8|mm}} of precipitation on average.
{{Weather box
|location = Letšeng-la-Terae
|metric first = yes
|single line = yes
|Jan high C = 14.8
|Feb high C = 14.5
|Mar high C = 12.2
|Apr high C = 10.6
|May high C = 7.7
|Jun high C = 5.4
|Jul high C = 5.4
|Aug high C = 6.8
|Sep high C = 9.9
|Oct high C = 11.2
|Nov high C = 12.6
|Dec high C = 13.7
|Jan mean C = 9.8
|Feb mean C = 9.7
|Mar mean C = 7.7
|Apr mean C = 5.1
|May mean C = 2.0
|Jun mean C = -0.1
|Jul mean C = 0.0
|Aug mean C = 1.5
|Sep mean C = 4.6
|Oct mean C = 6.0
|Nov mean C = 7.5
|Dec mean C = 8.9
|Jan low C = 4.8
|Feb low C = 4.9
|Mar low C = 3.3
|Apr low C = -0.3
|May low C = -3.6
|Jun low C = -5.5
|Jul low C = -5.3
|Aug low C = -3.8
|Sep low C = -0.6
|Oct low C = 0.8
|Nov low C = 2.5
|Dec low C = 4.1
|precipitation colour = green
|Jan precipitation mm = 133
|Feb precipitation mm = 119
|Mar precipitation mm = 120
|Apr precipitation mm = 67
|May precipitation mm = 20
|Jun precipitation mm = 10
|Jul precipitation mm = 8
|Aug precipitation mm = 24
|Sep precipitation mm = 57
|Oct precipitation mm = 89
|Nov precipitation mm = 115
|Dec precipitation mm = 119
|source 1 = Climate-data.org{{cite web
|url=http://en.climate-data.org/location/923374/
|title=Climate: Letšeng-la-Terae
|accessdate=26 April 2015}}
|date=April 2015}}
Significant diamond finds
= Lesotho Promise =
{{Main|Lesotho Promise}}
On 4 October 2006 the {{convert|603|carat|disp=flip}} white diamond, the Lesotho Promise was unearthed, which until the January 2018 discovery noted below was the largest reported find this century;
at the time it was found it was the 15th largest diamond ever found. The stone is of an exceptional colour, rated D, the top colour for diamonds.
= Lesotho Brown =
{{Main|Lesotho Brown}}
Previously the largest diamond found at Letšeng was the {{convert|601|carat|disp=flip}} Lesotho Brown, recovered in 1967.
= Letšeng Legacy =
On 13 September 2007 Gem Diamonds, Ltd. announced that it had found a {{convert|493.27|carat|g|disp=flip}} diamond, making it the 18th largest diamond ever found. It was sold to the Graff-SAFDICO partnership for $10.4 million.{{cite web |url=http://www.idexonline.com/FullArticle?Id=28784 |title=SAFDICO Pays $10.4M for 493 Carat Letšeng Legacy Diamond |date=November 15, 2007 |first=Edhan |last=Golan |website=International Diamond Exchange |accessdate=January 15, 2018}}
= Star of Lesotho =
In 2004, Gem Diamonds, Ltd. found a large diamond of {{convert|123|carat|disp=flip}}.{{cite web
|url = http://www.safdico.com/expertise/showcase/Star-of-Lesotho
|title = Star of Lesotho
|accessdate = 14 April 2008
|archive-url = https://web.archive.org/web/20081012132628/http://www.safdico.com/expertise/showcase/Star-of-Lesotho
|archive-date = 12 October 2008
|url-status = dead
}}
= Leseli La Letšeng =
On 21 September 2008 Gem Diamonds, Ltd. announced that it found a {{convert|478|carat|disp=flip}} diamond of high quality, making it the 20th largest diamond ever found. It is a type II D colour, with potential to yield a {{convert|150|carat|disp=flip}} cut stone. Chief executive Clifford Elphick said: "Preliminary examination of this remarkable diamond indicates it will yield a record-breaking polished stone of the very best colour and clarity, and has no inclusions visible in its rough form."{{Cite web |url=http://www.menafn.com/qn_news_story_s.asp?StoryId=1093213238 |title=menafn.com, World's 20th largest rough diamond found in Lesotho |access-date=22 September 2008 |archive-url=https://web.archive.org/web/20120212195006/http://www.menafn.com/qn_news_story_s.asp?StoryId=1093213238 |archive-date=12 February 2012 |url-status=dead }}[http://news.bbc.co.uk/2/hi/africa/7628475.stm news.bbc.co.uk, Massive diamond found in Lesotho]
|url=http://www.mg.co.za/article/2008-09-21-lesotho-mine-yields-one-of-worlds-largest-diamonds
|title= Lesotho mine yields one of world's largest diamonds
|date= 21 September 2008
|accessdate = 21 September 2008
}}
=November 2010=
The discovery of two large rough white diamonds was announced in November 2010.{{cite web|url=http://www.mining-journal.com/production-and-markets/gem-recovers-another-large-diamond-from-letšeng|accessdate=2010-11-10|title=Mining Journal - Gem recovers another large diamond from Letšeng|df=dmy-all}}{{dead link|date=July 2019|bot=medic}}{{cbignore|bot=medic}} They weighed {{convert|196|carat|disp=flip}} and {{convert|184|carat|disp=flip}}.{{cite web|url=http://www.mining-journal.com/finance/gem-sells-diamonds-for-us$22.7-million|accessdate=2010-11-28|title=Mining Journal - Gem sells diamonds for US$22.7 million|archive-url=https://web.archive.org/web/20101204073440/http://www.mining-journal.com/finance/gem-sells-diamonds-for-us$22.7-million|archive-date=4 December 2010|url-status=dead|df=dmy-all}}
=Lesotho Legend=
In January 2018 Gem Diamonds announced the largest diamond yet discovered at Letšeng, a Type IIa D color stone measured at {{convert|910|carat|disp=flip}}.{{Cite web |url=http://www.gemdiamonds.com/investors-press-pr-15012018.php |title=Gem Diamonds | Investors | Press release: Board changes |access-date=15 January 2018 |archive-url=https://web.archive.org/web/20180115185617/http://www.gemdiamonds.com/investors-press-pr-15012018.php |archive-date=15 January 2018 |url-status=dead }} It sold in March 2018 for $40 million.{{Cite web|last=Gibbs|first=Alexandra|date=2018-03-13|title='The Lesotho Legend': The fifth-largest gem diamond in history sells for $40 million|url=https://www.cnbc.com/2018/03/13/the-lesotho-legend-gem-diamond-sells-for-40-million.html|access-date=2021-03-29|website=CNBC|language=en}} The same year a light brown diamond of 357.61 carats was discovered.
=Letšeng Star=
In August 2011 a diamond of {{convert|550|carat|disp=flip}} was found.
=Letšeng Dynasty and Letseng Destiny=
In May and July 2015, the discovery of two large diamonds was announced : the Letšeng Destiny of {{convert|314|carat|disp=flip}} and the Letšeng dynasty of {{convert|357|carat|disp=flip}}.{{Cite web |url=https://www.gemdiamonds.com/about-our-diamonds.php |title=Gem Diamonds | About us | Our Diamonds |access-date=23 January 2019 |archive-date=24 January 2019 |archive-url=https://web.archive.org/web/20190124041607/https://www.gemdiamonds.com/about-our-diamonds.php |url-status=dead }}