Department of Mines & Geology
Ministry of Natural Resources
P.O. Box 750, Maseru 100                    
Phone: +226-32 3750
Fax: +226-31 0498

CIA Factbook
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The contribution of mining to total exports in 2010 amounted to 10.8%

Lesotho Mining News

Source: CIA Factbook



Lesotho is almost exclusively underlain by rocks of the Karoo Supergroup, overlying crystalline metamorphic basement, comprising sediments in the northwest and southwest and basaltic volcanics of the Drakensberg Group that dominate the central and eastern part of the country.


Diamonds are the main economic mineral of Lesotho and their production contributed almost 7% to the GDP in 2008. Diamond production increased by 10.5% and the country was ranked 12th in Africa for volume of production in 2008. The main resource of diamonds has been the Letseng mine which produces stones with the highest dollar ratio per carat of any diamond mine in the world. The Kao diamond mine entered its first production phase in 2008 and is expected to produce about 700,000 carats per year. The main Kao kimberlite pipe with a diamond resource of 12.4 Mct is the largest in Lesotho and fourth largest in Southern Africa. Karoo sediments are potential low tonnage sources of uranium and semi-precious stones such as agate, amethyst and zircon are exploited on a small scale. Additionally coal and coal-bed methane are unproven energy mineral possibilities.

Maps and images

Minki van der Westhuizen, at the Letseng mine in Lesotho, displays four diamonds with a combined weight of 366 carats. At the time, the operating company expected them to fetch a minimum of US$6 million.
Source: JCI

Click HERE for an overview

Lesotho contains some of the most elevated diamond deposits   in  the  world,   all  of   which   are  hosted   by kimberlite. The first discovery  was made in 1954 at Kao 1,  50  km  southeast  of  Buthe  Buthe, though   several   nondiamondiferous  kimberlites were known prior to that  time. The first kimberlites  were found  by locating  abandoned  workings that  had been used  to  exploit  ilmenite  for  pigments. Later,  kimberlite indicator   mineral  sampling, supplemented   by  airborne  and  ground   magnetic   surveys, photogeology, pitting and  drilling   were  the  methods used  for  kimberlite   exploration.  Approximately  200 kimberlite bodies have been discovered, only  eight  of  which, in northern  Lesotho, are significantly  diamondiferous. Five of these have been exploited on a small scale since 1955.

A large proportion of the country is underlain by the southern portion of the Archean Kaapvaal craton, host to kimberlites and economic diamond deposits in southern Africa. More than 200 kimberlite occurrences are known in Lesotho, primarily dykes but including approximately 33 volcanic pipes of which 24 are reportedly diamondiferous. They are Cretaceous in age and intrude flat-lying Triassic sedimentary rocks and a thick sequence of Jurassic flood basalt.
The country has a long history of diamond production, mainly from alluvial deposits. De Beers mined the Letseng la Terae kimberlite between 1976 and 1982 and produced in the order of 280,000 carats. The Letseng la Terae kimberlite was recently put back into production and has the distinction of producing some of the highest dollar value per carat diamonds in the world. Diamond grades at Letseng la Terae are very low, between 2 and 2,5 carats per one hundred tonnes of kimberlite, but diamond value is reported to be over US$1,000 per carat. This high average diamond value is a result of consistent but infrequent recovery of very large, exceptional quality diamonds.
Other Lesotho kimberlites of economic interest and in varying stages of development / evaluation include the Liqhobong, Kao and Kolo occurrences.

Lesotho Kimberlite Locality Map
  • Gem Diamonds Ltd [LSE:GEMD] is operating the Letšeng mine. It has been producing 50,000 carats a year, but, with fresh investment under its new owners, it plans to double that to about 100,000 carats a year.
    Letšeng Diamonds Limited is owned 70% by Gem Diamonds and 30% by the Government of the Kingdom of Lesotho. Operated by De Beers between 1977 and 1982, Letšeng was reopened in 2004 and acquired by Gem Diamonds in 2006. Letšeng Mine consists of two primary vertical kimberlite pipes, together with deposits of alluvial gravels. The two pipes are adjacent with cone-shaped sections and confirmed vertical depths of 495 m and 655 m, respectively. Recent average grade across the two pipes is 2,06 cpht. Letšeng currently has a processing capacity of approximately 2,6 million tonnes per annum, but a recent decision to invest US$45 million in its processing capacity will see this double to 5,2 million tpa by end 2008. Letšeng has produced two of the world's largest diamonds - the 601 cts Lesotho Brown in the mid 1960's and the 603 cts Lesotho Promise recovered in September 2006 (the 15th largest diamond ever recovered). The Lesotho Promise was sold for US$12,4 million.
The Lesotho Promise diamond weighing 603 carats which was sold for $12,4m.
Source: Gem Diamonds

Letseng Diamond Mine
Source: http://sprottglobal.com/natural-resource-investing/site-visits/?albumId=1508

Source: http://www.miningweekly.com/article/gem-diamonds-lowers-production-guidance-for-2013-2013-07-29
  • Motapa Diamonds Inc is exploring the Mothae kimberlite where previous sampling undertaken in 1966 by Lonrho Ltd , yielded a grade of approximately 2,8 carats per hundred tonnes.
  • European Diamonds plc [AIM:EPD] has a near-surface resource at its Liqhobong project in Lesotho of 13,4 million tonnes at 0,283 carats per tonne with a gross value of $265m at an estimated $70/carat. The company is currently (2007) producing around 20,000 carats/month from the mine, with plans for an expansion. The independently verified resource at the main pipe kimberlite has been measured to 45 metres below surface. The main kimberlite pipe is known to extend to 650 metres below surface. Shareholders of European Diamonds approved the proposed name change to Kopane Diamond Developments in November, 2007. The company’s stock ticker number, which was previously EPD, will become KDD, and the new website address will be http://www.kopanediamonds.com
  • Thabex Exploration [JSE: TBX], through 70%-owned, Angel Diamonds Pty) Ltd, is exploring the Kolo kimberlite pipe, 38 km south-west of Maseru in the Mafeteng district.
  • Lesotho Diamond Corporation plc (Registered in Gibraltar) has the rights to the Kao kimberlite pipe in Lesotho's Buthe Buthe district and was attempting to raise money to develop a mine. River Diamonds plc (RVD.L) announced in April 2007 that they have entered into an agreement to purchase a 4,8% working interest in Lesotho Diamond Corporation plc for £4 million with an option to acquire a further 2,3% by 20th April 2008 for £2,121,212. The Kao pipe has a proven and probable reserve of 147 million t at a grade of 6,9 carats per hundred tonnes. SRK Consulting has calculated the Net Present Value of Kao to be £129m, assuming a base case of US$240/carat. In May 2007 Pangea Diamond Fields had a conditional cash and shares offer accepted to buy at least 40% of Lesotho Diamond Corporation (LDC). According to Pangea's statement, key shareholders in LDC approached Pangea to make a rival offer after an agreement was struck to sell shares in LDC to River Diamonds.
Latest (2012):
  • Gem Diamonds Limited (70%) and the Government of Lesotho (30%) has a resource of 3.6 million carats (as at 31 December 2010) with an average value of US$ 2 776 per carat at the Letseng Mine. 
  • Namakwa Diamonds Ltd (62.5%), the Government of Lesotho (25%) and balance to local Basotho citizens through a public vehicle was looking at mining the Kao kimberlite with 2.5Mt of the higher grade K6 facies (19.38cpht); and 11.9Mt of hard and soft kimberlites from the K-Other facies.(6.6cpht).
  • Firestone Diamonds plc (75%), Government of Lesotho (25%) has a resource of 90.66 Mt at an average grade of 34.3cpht containing 31.14 million carats, with an independent run of mine valuation of US$86 per carat (September 2008 valuation) aLiqhobong
  • Paragon Diamonds Ltd (85%) has an indicated resource of 30Mt down to 200 metres  at the Lemphane kimberlite pipe. Aim-listed Paragon Diamonds has finalised the design and order of a $6-million 75 t/h processing plant for the Lemphane kimberlite mine, inLesotho. The mine is owned by Paragon’s 80%-owned subsidiary Meso Diamonds. The diamond development company would establish the new modular plant in time for the mine’s Stage 1commissioning in the first quarter of 2015, which would result in the extraction of one-million tonnes of kimberlite over a two-year period,Paragon chairperson Philip Falzon Sant Manduca said on in November 2014.
  • Lucara Diamond Corporation (75%), Government of Lesotho (25%) stated that preliminary drilling shows global tonnage potential of 25-35 million tonnes based on drilling results to a depth of 200 m at the Mothae kimberlite pipe. Sampling to date shows grade potential of between 3 and 4 carats per hundred tonnes.
  • Thabex Ltd (70% of Angel Diamonds), Peter Mosebo & Cornelius Engelbrecht (30%) has an inferred diamond resource of 2.2 million tonnes at an average grade of 14.1cpht or 310 000 carats, estimated from surface to 50m below the level of the regional drainage.

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Economic geology, geology of nonmetal deposits

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