DOCSLIB.ORG

Karowe Diamond Mine: a World-Class Source of Large Exceptional Diamonds John P

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Karowe Diamond Mine: a World-Class Source of Large Exceptional Diamonds John P 11th International Kimberlite Conference Extended Abstract No. 11IKC-4647, 2017 Karowe Diamond Mine: A World-class source of large exceptional diamonds John P. Armstrong Lucara Diamond, Vancouver, CA, [email protected] Introduction The Karowe Mine (AK6 kimberlite), owned and operated by Lucara Diamond, located in the Republic of Botswana, achieved commercial diamond production in July 2012 (Figure 1). Between July 2012 and December 2016 over 1.8 million carats have been mined and sold generating in excess of US$1 billion dollars in revenue. The AK06 kimberlite within the Orapa Kimberlite field is a roughly north-south elongate kimberlite body with a near surface expression of ~3.3 hectares and a maximum area of approximately 7 hectares at approximately 120 m below surface. The body comprises three geologically distinct, coalescing lobes that taper with depth. These are referred to as the North Lobe, Centre Lobe, and South Lobe. 10% 9% 8% 7% 6% 5% 4% 3% Weight Percent>10.8 ct Weight 2% 1% 0% Q3-12 Q4-12 Q1-13 Q2-13 Q3-13 Q4-13 Q1-14 Q2-14 Q3-14 Q4-14 Q1-15 Q2-15 Q3-15 Q4-15 Q1-16 Q2-16 Q3-16 Q4-16 Q1-17 Figure 1 (left). Location of Karowe Mine, AK06 kimberlite, Orapa District Botswana Figure 2 (right). Weight percent of +10.8 carat diamonds on quarterly carat production Karowe Mine Q3 2012 to end of March 2017. Kimberlite Geology The AK6 kimberlite is an opaque-mineral-rich monticellite kimberlite, texturally classified primarily as fragmental volcaniclastic kimberlite with lesser macrocrystic hypabyssal facies kimberlite of the Group 1 variety. The nature of the kimberlite differs between each lobe with distinctions apparent in the textural characteristics. The South Lobe is considered to be distinctly different from the North and Centre Lobes . The North and Centre Lobes exhibit internal textural complexity whereas the bulk of the South Lobe is more massive and internally homogeneous. The South lobe forms the majority of the resource and displays the coarsest diamond size distribution of the three lobes. The proportion of +10. 8 carat diamonds increases from approximately 1.8 weight percent in the North Lobe to in excess of 4 weight percent within the South Lobe. Early mining focused on the higher grade North Lobe (Q3 2012 to Q1 2013, Figure 2), as production shifted into the Centre and South Lobes the size distribution became coarser in nature. The AK6 kimberlite has established a continuing production of large, high value diamonds (Figures 2 and 3). In March 2013 a 239 carat gem quality diamond was recovered which marked the first in a continuing population of large high value Type IIa diamonds recovered from the Centre Lobe and more importantly the South Lobe of the AK6 kimberlite. Recognition of a coarse diamond size distribution supported through size distribution analysis, breakage studies, and optimization of processing circuits has maintained and enhanced the recovery of large diamonds. Large diamonds >50 carats in size are spatially distributed horizontally and vertically within the South Lobe. Continuity of large diamond recovery is shown for yearly +10.8 carat diamond production normalized to annual total carat production (Figure 3a) and as total volume of +10.8 carat diamonds produced (Figure 3b). Karowe +10.8 diamonds: Cumula>ve % of Annual Produc>on Karowe Cumula>ve Specials (ct) 8% 25000 2013 2014 2015 2016 7% 2013 2014 2015 2016 2017 20000 6% 5% 15000 4% 10000 3% Cumula>ve Wt.% 2% Cumula>ve Carats 5000 1% 0% 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Month Figure 3a/b. Cumulative +10.8 carat production on a monthly basis normalized to total annual production. Overlap in yearly trends demonstrates stability in large stone recovery. Anomalous uptick noted in November 2015 related to the recovery of above average +10.8 carat production including the 1109 Lesedi La Rona and the 813 carat Constellation. Figure 3b, cumulative +10.8 carat diamond annual production by month for life of mine to end of Q1 2017. Process plant optimization, including incorporation of sensor-based bulk sorting (X-Ray Transmission), was undertaken to allow treatment of harder, high yielding kimberlite at depth within the South Lobe, and allow the recovery of large diamonds from primary ROM feed pre-concentration. In late 2015 the Karowe Mine recovered an 813 carat stone and the World’s second largest gem quality diamond in over 100 years weighing 1,109 carats. Diamonds greater than 10.8ct in weight represent approximately 4.8% by weight of all diamond production over the life of mine to date. Life of Mine average stone size for the +10.8ct production is 28.9 ct/stone. Log-Log probability plots (carats) of the +10.8 carat recovered diamond population, comprised of in excess of 90,000 carats and over 3200 individual diamonds display evidence for diamond damage/loss in the +100 diamond sizes (Figure 4). Reconstruction of large broken diamonds results in a coarser size distribution model, however, there is still evidence that the diamond population is impacted by the non-recovery of large +100 carat diamonds. This non-recovery of large diamonds may be the result of breakage and/or the host kimberlite has not been processed. Assessment of the size frequency distribution suggests the AK6 kimberlite will continue to produce large and exceptional diamonds. - 2 - 3 2 1 0 -1 Probability Score (Z) -2 -3 LoM Recovered LoM Reconstructed -4 10 100 1000 Stone Size (ct) Figure 4. Log-Log Probability diagram for AK6 Life of Mine +10.8 carat diamonds on an as recovered and reconstructed basis. - 3 - .
Load more

Recommended publications
  • Why Buyers Shunned the World's Largest Diamond
    WHY BUYERS SHUNNED THE WORLD’S LARGEST DIAMOND At 1,109 carats, big as a tennis ball, the world’s largest uncut diamond was expected to shatter records at a June Sotheby’s auction. How did the dazzling stone go unsold? An exclusive reveals what went wrong. BY MATTHEW HART AUGUST 5, 2016 5:00 AM BUT IS IT ART? The 1,109-carat Lesedi La Rona diamond, on view at Sotheby’s in New York in May. By Justin Lane/EPA/Redux. The assassination of William Lamb began at 6:45 P.M. on a soft June night. Spectators packed the killing ground, a sales room on the second floor of Sotheby’s, in London. The victim wore the raiment of his caste, a crisp tuxedo. A few yards in front of where he sat, blazing in its spotlight on a plinth beside the auctioneer, was a 1,109-carat top-color white diamond called Lesedi La Rona, the vessel of Lamb’s hopes for a bold new way to sell rough diamonds. His wife had bought him new shoes for the occasion, the toe caps spattered with faux gems. He wore socks patterned with jaunty slashes of color. The Lesedi diamond opened at $50 million and struggled from the start. Fifty-one million dollars, someone offered, and too long after that, $52 million. This was not the scenario that Lamb had imagined in his dreams. In that version, a forest of bidding paddles would have shot up in the room as eager buyers drove the price north of $100 million.
    [Show full text]
  • THE WOMEN SHAKING up DIAMONDS and INDUSTRY NORMS with Eira Thomas, CEO and Naseem Lahri, Botswana MD, Lucara Diamond
    is proud to present CELEBRATING STRONG WOMEN IN JEWELRY EPISODE I THE WOMEN SHAKING UP DIAMONDS AND INDUSTRY NORMS With Eira Thomas, CEO and Naseem Lahri, Botswana MD, Lucara Diamond @lucaradiamond In support of the Gem X Scholarship Fund @gemxclub Donation link: gemx.club/charity THE GEM X SCHOLARSHIP FUND Opening the World of Jewelry to More Learners We wish to support those with the greatest enthusiasm, passion and need. Gem X Scholars will receive: Educational financial assistance Complimentary Gem X membership and networking opportunities Bespoke mentorship, designed to help scholars reach their career goals Please give at www.gemx.club/charity THANK YOU FOR YOUR SUPPORT! Cautionary Statement Forward‐looking information Certain of the statements made and contained herein and elsewhere constitute forward- the growth of the Clara platform, the timing and frequency of sales on the Clara looking statements as defined in applicable securities laws. Generally, these forward- Platform, and the quantum of and timing for participation of third parties on the Clara looking statements can be identified by the use of forward-looking terminology such as platform; expectations regarding the need to raise capital and its availability; possible "expects", "anticipates", "believes", "intends", "estimates", "potential", "possible" and similar impacts of disputes or litigation; and other risks and uncertainties described under the expressions, or statements that events, conditions or results "will", "may", "could" or "should" heading “Risks and
    [Show full text]
  • Lesedi La Rona & Lucara
    Lesedi La Rona & Lucara Big Rocks, Big Dreams and Small Companies On the eve of the highly anticipated auction at Sotheby’s London of the largest gem-quality rough diamond in the world – the 1,109-carat Lesedi La Rona – the Diamond Loupe brings you our in- depth discussion with Lucara Diamond CEO Wil- liam Lamb. During the Antwerp leg of the Lesedi’s world tour, we sat down with William Lamb to dis- cuss Lucara’s management strategy, decision-mak- ing process, use of innovative technology and, of course, the magnificent Lesedi La Rona. What lies in store for Lucara’s historic stone? The Karowe Mine, former owner De Beers’ vs. current owner Lucara’s approach It is all about scale and approach. De Beers sold the mine because it did not fit with their large-mine process. De Beers would call it ‘elephant hunting’. They are out there looking for mines that would have 30 to 40-year life spans, and would implement a more ‘Rolls Royce’ type technical solution. This type of sheer volume involves much more cost- ly capital expenditure, and is precisely why we finally relinquished the Mothae Mine. Believe me, we looked at it six ways of Sunday, at all the alternatives … small scale, large scale, new technology, old technology … and we couldn’t get it to work. Whereas a number of junior companies like us are now implementing what we call a ‘fit-for purpose’ solution that is not a Rolls Royce, but a sort of VW-type solution that can extract value from smaller deposits that the majors would not consider economical.
    [Show full text]
  • Apr- the Lesedi La Rona Diamond
    Learning Series: The Wonder and Natural Beauty of Rocks The Saga of the Lesedi la Rona Diamond The 1,109-carat uncut Lesedi la Rona diamond is the largest gem-quality diamond discovered in more than century and the second-largest diamond ever found. It is exceeded in size only by the 3,106-carat Cullinan found in South Africa in 1905; itself cut into over 100 pieces, including nine numbered stones—among them the Great Star of Africa (530 carats) which has adorned the Royal Scepter of the British Crown Jewels since 1910. The size of a tennis ball, the Lesedi la Rona, was recovered in Botswana in November 2015 at the Karowe mine operated by the Canada-based firm, Lucara Diamond Corporation. It weighs nearly half a pound (227 grams), measures 65 mm by 56 mm by 40 mm and is believed to be between 2.5 billion and 3 billion years old. Classed as a Type IIA diamond, it is among the most valued and purest type of diamonds; less than 2% of all gem diamonds are Type IIA. Scientifically speaking, Type IIA stones are almost pure carbon. They contain no significant amount of nitrogen in the crystal lattice (which imparts a yellowish hue) and often show extraordinary optical transparency; both are true of the Lesedi la Rona. What’s in a Name? Following the diamond’s discovery, the CEO of Lucara launched a competition to name the stone – open only to Botswana citizens. In addition to the honor of having their suggestion selected from among all the entries, the winner would take home P25,000 (about $2,170).
    [Show full text]
  • Lucara Diamond Corp. Full Year 2015 Results Cautionary Statement 2
    Lucara Diamond Corp. Full Year 2015 Results Cautionary statement 2 Forward‐looking information • This investor presentation contains forward‐looking statements and information as defined in applicable securities laws including: the estimates of the Company’s mineral reserve and resources; estimates of the Company’s production and sales volumes, revenue for the Karowe Mine; exploration and development plans and objectives, production costs, exploration and development expenditures. Generally, these forward‐looking statements can be identified by the use of forward‐looking terminology such as “expects”, “anticipates”, “believes”, “intends”, “estimates”,“potential”, “possible” and similar expressions, or statements that events, conditions or results “will”, “may”, “could” or “should” occur or achieved. Forward‐looking statements are based on the assumptions, opinions and estimates of management as of the date such statements are made, and they are subject to a number of known and unknown risks and uncertainties which may cause the actual results, performance or achievements of the Company to be materially different from any future results, performance or achievement expressed or implied by such forward‐looking statements. In particular, such risks include general business and economic conditions, changes in interest and foreign currency rates, the supply and demand for, deliveries of and the level and volatility of prices of rough diamonds, costs of power and diesel, acts of foreign governments and the outcome of legal proceedings, inaccurate
    [Show full text]
  • Dear BOTSFA Members
    Newsletter from Botswana Sweden Friendship Association No 3/2017 BOTSFA Dear BOTSFA members FOLLOWING THE CELEBRATIONS OF BOTSWANA 50 in September last year, botsfa has continued to be an association where friends meet. The informal-get-togethers that are held at Grappa restaurant in Stockholm attract a sizeable audience. On September 18, Mike Main, a freelance writer who lives in Gaborone and spends much of his time travelling in Botswana, made a very informative presentation entitled »Botswana Bushmen: Quo Vadis?«. This was followed by an over- night boat cruise to Åland in celebration of Botswana50+1 independence anniversary. This time, the audience was treated to a yet another thought-provoking presentation by Professor Johan Brosché of Uppsala University on factors found to contribute to the half a century of peace in Botswana. Sixty botsfa members were on the cruise, including Botswana’s Ambassador to Sweden Mr. Lameck Nthekela, Mrs. Ikanyeng Nthekela and staff of the Embassy. botsfa will continue to work on programs that provide its membership opportunities for information sharing and discussions. In this Dumela, you will read about a recently pub- lished cookbook »Taste of Botswana« by a botsfa mem- ber, Ednah Rosen, and the story of the biggest diamond, »Lesedi la Rona«, mined in Botswana and recently sold for usd 53 million, visits by botsfa’s Vice Chairperson to India and by Maru-a-Pula students to Sweden. Julia Majaha-Jartby botsfa Chairperson Welcome to BOTSFA! MEMBERSHIP FEES Plusgiro 85 10 39-8, or Bankgiro 428-6472 • Individual: SEK 175 • Family: SEK 300 (incl. children up to 15) For an update of records, please send an e-mail to [email protected] • Student: SEK 100 if you have changed contact details or are paying as a new member.
    [Show full text]
  • Des Nouveaux Travailleurs Et SST : Deux Défis Qui Vont De Pair
    Le BelmineUne publication de la Commission des normes, de l’équité, de la santé et de la sécurité du travail No 46, automne 2016 ENJEU IMPORTANT Intégration des nouveaux travailleurs et SST : deux défis qui vont de pair Être vu sous terre Équipements Écaillage est maintenant de protection obligatoire individuels Mot de la rédaction e succès de l’exploitation minière est tributaire de plusieurs Dans cette foulée, en pages 4 et 5, le lecteur constatera facteurs : un sol prospère, les bons équipements, l’utilisation sans surprise que l’intégration des nouveaux travailleurs et de techniques adéquates, une main-d’œuvre compétente, la SST vont de pair. Les facteurs à considérer pour faciliter Lle réseau, l’organisation du travail, la recherche et le dévelop- le transfert des connaissances entre les travailleurs plus pement, etc. La synergie entre ces facteurs et la coordination expérimentés et ceux nouvellement embauchés y sont des activités est primordiale, car si l’une progresse au détriment abordés. Plusieurs pistes d’intervention novatrices, comme des autres, cela peut déstabiliser l’ensemble et compromettre adapter la production aux impératifs de formation, et les conditions de succès. d’autres mesures plus traditionnelles, comme le jumelage et la transmission des bonnes pratiques, en font partie. Ce numéro d’automne, dont la page couverture montre un travail- D’ailleurs, la page 8 présente un texte de l’Association leur d’expérience et un autre moins expérimenté qui échangent paritaire pour la santé et la sécurité du travail du secteur sur les rouages du métier, met en évidence la santé et la sécurité minier portant sur les équipements de protection.
    [Show full text]
  • The Political Economy of Marketing the Historic Lesedi La Rona Diamond
    A Special Issue on Botswana Notes and Records’ Golden Jubilee Volume in Honour of Sir Ketumile Masire ‘The Rock Star that Got Stage Fright at Auction’: The Political Economy of Marketing the Historic Lesedi La Rona Diamond Christian John Makgala∗ and Maitseo Bolaane§ One hundred years’ worth of history is not something you can change with a single auction Lukas Lundin Abstract In 1905 the largest diamond in history measuring 3,106-carat was discovered at Premier Mine near Pretoria in South Africa, and was presented to King Edward VII of Great Britain for his 66th birthday on 9 November 1907. After 110 years the second largest diamond in history was discovered by the Canadian company Lucara at its Karowe Mine in Botswana in November 2015, and the gemstone became ‘Botswana’s pride’. The 1,109-carat diamond, which came to be called ‘Lesedi La Rona’, brought great excitement globally as the news of its discovery allegedly received more than one billion hits in the Internet in just two weeks. The diamond went on a global road show with promotional stops in Singapore, Hong Kong, Dubai, Geneva, New York, and London. This massive publicity was expected to make the stone the most expensive gem ever sold. The sale of the rough diamond in an open auction in London was also hoped to significantly ramp up the global diamond market which had slumped badly at the time. However, this paper observes that the anticipated hefty price for the historic gem and its attempted sale at an open auction as opposed to traditional secretive operation rendered the stone problematic to the diamond industry in general and to Lucara in particular.
    [Show full text]
  • News Release Lucara Reports Strong Operational Results in a Year of Historic Diamond Recoveries
    NEWS RELEASE LUCARA REPORTS STRONG OPERATIONAL RESULTS IN A YEAR OF HISTORIC DIAMOND RECOVERIES February 23, 2016 (LUC – TSX, LUC – BSE, LUC – Nasdaq Stockholm) Lucara Diamond Corp. (“Lucara” or the “Company”) reports full year revenues of $224 million for the year and cash of $134.5 million. All figures are in U.S. dollars except for the dividend. HIGHLIGHTS: The recovery of the Lesedi La Rona in November 2015, the first diamond over 1,000 carats to be recovered in more than 100 years and the largest ever from a Botswana operation. The Company is very pleased to be provided with the opportunity to soon showcase the historic Lesedi La Rona to the President of Botswana and his cabinet. Financial: EBITDA for the period year was $134 million (2014: $173.4 million), with an EBITDA margin of 60%. Return on equity was 30%. Net cash position $134.5 million (2014: $100.8 million). Year to date costs at $29 per tonne ore processed were well controlled and were below forecast. Plant optimization, bulk sample plant project and sustaining capital costs were all within forecast. Full year earnings per share were $0.21 per share (2014: $0.13 per share). 2015 year end diamond inventory includes over 60,000 carats. The Company’s first exceptional stone tender is closing on April 13, 2016, which excludes the three large stones recovered and announced in November 2015. Operational: Karowe Mine Recovery of the Lesedi La Rona (1,109 carats) and the 813 carat stone. The largest and second largest gem quality diamonds ever to be recovered in Botswana.
    [Show full text]
  • Sotheby's Catalog
    Sotheby's Lesedi La Rona London | 29 Jun 2016, 06:30 PM | L16059 LOT 1 LESEDI LA RONA THE LARGEST GEM QUALITY ROUGH DIAMOND TO BE DISCOVERED IN OVER A CENTURY THE LARGEST GEM QUALITY DIAMOND IN EXISTENCE TODAY AN HISTORIC ROUGH DIAMOND The rough diamond of high colour and purity weighing 1,109 carats and measuring approximately 66.4 x 55 x 42mm. ESTIMATE Estimate Upon Request Accompanied by a GIA letter stating the rarity and characteristics of the stone. CATALOGUE NOTE It is a huge privilege for Sotheby’s to have been chosen by Lucara Diamond Corp. to offer Lesedi La Rona for sale. Indeed, it is a unique honour as no other rough diamond of even remotely similar size has ever been proposed for public auction. What has struck me personally, since I first held this phenomenal gemstone in my hands, is how well it embodies the symbolism that Man has invested in diamond since remote antiquity – ideas of permanence, indestructability, immutability, and of course, adamantine hardness. Just try to imagine the epic journey this stone has undergone to arrive with us. Having been formed as a result of unimaginable temperatures and pressures, soon after the birth of the earth itself – some two to three billion years ago – the crystal then waited until, by chance, perhaps a billion years later, it became associated with a volcanic eruption that carried it upwards a distance of over 100 miles towards the surface. Having survived that tumultuous passage it still had to undergo the dramatic explosions and crushers associated with the mining process before eventually seeing the light of day – and the gaze of man – on the 16th November 2015.
    [Show full text]
  • 2018 Sustainability Report Making Diamond History 3 Lucara Diamond Corp
    2018 SUSTAINABILITY REPORT MAKING DIAMOND HISTORY 3 LUCARA DIAMOND CORP 5 Message from the President and CEO 7 Governance & Ethical Conduct 14 Economic Performance 16 LUCARA BOTSWANA 17 Message from the Managing Director 18 Message from the General Manager, Karowe Diamond Mine 20 Charter & Policies 21 Operations & Exploration Activities 25 Our People 29 Health & Safety 33 Engagement 36 Impact Investment 40 Environmental Performance 54 CLARA DIAMOND SOLUTIONS 55 About Clara 56 MATERIALITY ANALYSIS 60 ASSURANCE STATEMENT 64 CAUTIONARY STATEMENT Cover page images (counter clockwise): Tending to farmed vegetables at Mokubilo community farming project (top); Grade control geologists discussing ore loading, Karowe Mine (middle); Community event near the Karowe Mine (bottom); 240 carat diamond recovered in Q1/19, Karowe Mine Left: Karowe open pit mine CORPORATE PROFILE Lucara Diamond Corp. (Lucara) is a Canadian diamond mining company headquartered in Vancouver. Lucara is a member of the Lundin Group of Companies and is listed on the Toronto Stock Exchange (TSX), Nasdaq Stockholm and the Botswana Stock Exchange under the symbol "LUC". Lucara complies with the Kimberley Process, is certified under the Responsible Jewellery Council Code of Practices, and is a signatory to the UN Global Compact. The Karowe Diamond Mine (Karowe) is operated by Lucara's wholly-owned subsidiary Lucara Botswana (Pty) Limited (Lucara Botswana). Karowe is one XRT (X-ray transmission) circuit buildings and processing plant of the world's foremost producers of large, high quality diamonds in excess of 10.8 carats, including the historic 1,109 carat Lesedi La Rona and the ABOUT THIS REPORT 813 carat Constellation. The mine has been in production since 2012.
    [Show full text]
  • H1 - 2016 Cautionary Statement
    H1 - 2016 Cautionary Statement Forward-looking information This investor presentation contains forward-looking statements and information as defined in applicable securities laws including: the estimates of the Company’s mineral reserve and resources; estimates of the Company’s production and sales volumes, revenue for the Karowe Mine; exploration and development plans and objectives, production costs, exploration and development expenditures. Generally, these forward-looking statements can be identified by the use of forward-looking terminology such as “expects”, “anticipates”, “believes”, “intends”, “estimates”, “potential”, “possible” and similar expressions, or statements that events, conditions or results “will”, “may”, “could” or “should” occur or achieved. Forward-looking statements are based on the assumptions, opinions and estimates of management as of the date such statements are made, and they are subject to a number of known and unknown risks and uncertainties which may cause the actual results, performance or achievements of the Company to be materially different from any future results, performance or achievement expressed or implied by such forward-looking statements. In particular, such risks include general business and economic conditions, changes in interest and foreign currency rates, the supply and demand for, deliveries of and the level and volatility of prices of rough diamonds, costs of power and diesel, acts of foreign governments and the outcome of legal proceedings, inaccurate geological and recoverability assumptions
    [Show full text]