Fort a LA Corne Joint Venture Significant Proportions of Type Iia Diamonds from STAR Kimberlite Trench Cutter Sampling, Large Stones Exhibit High Diamond Prices
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NEWS RELEASE May 31, 2022
TSX: DIAM Saskatoon, Saskatchewan
FORT A LA CORNE JOINT VENTURE
SIGNIFICANT PROPORTIONS OF TYPE IIa DIAMONDS FROM STAR KIMBERLITE
TRENCH CUTTER SAMPLING, LARGE STONES EXHIBIT HIGH DIAMOND PRICES
SASKATOON, Saskatchewan, May 31, 2022 – Star Diamond Corporation (“Star Diamond or the Corporation ”) is
pleased to announce that the Corporation has completed a study into the abundance of Type IIa diamonds in the
Trench Cutter diamond parcels recovered from the Early Joli Fou (“EJF”) geological units at the Star Kimberlite, as
defined by the Star Diamond g eological model. The Star Kimberlite is located within the Fort à la Corne diamond
district of central Saskatchewan, Canada (which contains the Star - Orion South Diamond Project ), on mineral
dispositions held in a joint venture with Rio Tinto Exploration Canada Inc. (“Rio Tinto Canada”). During 2019, Rio
Tinto Canada completed the drilling of ten bulk sample holes (trenches) on the Star Kimberlite using a Trench Cutter
Sampling Rig. This study confirms that unusually high proportions of Type IIa diamonds are present in the Star
Kimberlite. Of particular note is the exceptionally high proportion of Type IIa diamonds in the larger size fractions
of the EJF of which 53 percent (8 of the 15) of the largest stones, 4 carats and above are Type IIa. This study also
confirms and augments earlier studies conducted by Star Diamond of Type IIa diamonds at Star (26.5 percent, +11
DTC (0.32 carats) and above) (see News Releases dated June 09, 2010, March 4, 2019 and May 02, 2022). Type IIa
diamonds are very rare and account for less than 2 percent of all natural rough diamonds mined from kimberlites.
Many high-value, top colour, large specials (greater than 10.8 carats) are Type IIa diamonds, which include all ten
of the largest known rough diamonds recovered worldwide.
The number and the percentage of Type IIa diamonds for the Trench Cutter EJF sampl es are documented in the
table below.
Star EJF Kimberlite (Diamonds +9 DTC (0.18 carats) to 15 carats)
Number of
Diamonds Typed
Number of Type IIa
Diamonds
Percentage Type IIa
Diamonds
EJF +9 (0.18 ct) & above 1,229 353 28.7
EJF +11 (0.32 ct) & above 615 196 31.9
EJF 4 carat & above 15 8 53.3
As can be seen from the table above, a significant number of diamonds from the EJF geological units of the Star
Kimberlite have been analyzed and typed from the Trench Cutter program. The diamonds analyzed represent a
spectrum of diamond sizes from +9 DTC (+0.18 carats) through all the large stones, up to diamonds of over 15 carats.
The largest Type IIa diamond identified is a 16.96 carat stone.
The twelve highest value stones from the EJF trench cutter samples (3 carats and above) are listed in the table
below. Of note is that nine of these twelve highest value stones are Type IIa. Diamond descriptions and valuations
were completed by Mr. Nelson Karun, Diamond Specialist, Saskatchewan Research Council ( “SRC”) Diamond
Services, on behalf of Star Diamond:
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Size
(carats)
Type Colour Model Estimated Price
US$/Carat
Estimated Stone
Value US$
16.96 IIa D Makeable 6,500 110,240
7.29 IIa D Makeable 10,500 76,545
8.10 IIa D Makeable 6,406 51,889
6.36 IIa D Makeable 5,214 33,161
10.13 IIa TLB1 Makeable 2,514 25,467
6.52 IIa G Makeable 1,894 12,349
6.28 IIa TLB Makeable 1,851 11,624
3.44 I H Sawable 3,286 11,304
3.30 I I Makeable 2,209 7,290
3.20 IIa VTLB(H)2 Makeable 2,209 7,069
5.15 I J Makeable 1,183 6,092
4.08 IIa D Makeable 1,250 5,100
1 TLB: Top Light Brown
2 VTLB: Very Top Light Brown Polishes to the equivalent of H colour
The previous three highest value stones, recovered from the Star and Orion South Kimberlites were also described
and valued by Mr. Nelson Karun, on behalf of Star Diamond:
Kimberlite Size
(carats)
Type Colour Model Estimated Price
US$/Carat
Estimated Stone
Value US$
Star LDD* Inner EJF 11.96 IIa D Makeable 13,787 164,893
Orion South Underground
EJF
15.88 IIa D/E Makeable 6,040 95,915
Orion South LDD* EJF 10.52 I Fancy Light
Yellow
Makeable 8,300 87,316
* LDD = large diameter drilling
Only a small number of active diamond mines regularly produce Type IIa diamonds with the most important of
these mines being Letseng-la-Terae (Letseng Mine) in the Kingdom of Lesotho and more recently Karowe in
Botswana. While Letseng is a low grade (1.5 -3 cpht) kimberlite and Karowe has a grade of approximately 15 cpht,
they are probably the most prolific source of large high -value Type IIa diamonds, which contribute to making
Letseng and Karowe highly economic deposits. Type IIa diamonds contain no nitrogen or boron impurities and are
frequently either top white colours (D, E, F or G) or any shade of brown. Many pink and brownish -pink diamonds
are also Type IIa. Type IIa diamonds usually have anhedral crystal shape and exhibit a range of elongated, distorted,
or irregular morphologies. Most importantly, many high-value, top colour, large specials (greater than 10.8 carats)
are Type IIa diamonds, which include all ten of the largest known rough diamonds recovered worldwide, from the
890 carat Incomparable to the 3,106 carat Cullinan.
Statistics on the proportions of Type IIa diamonds produced by diamonds mines are not freely available. However,
Bowen et al (2009) published Type IIa FTIR measurements for 484 plus two carat diamonds from the Letseng
Diamond Mine. The Letseng Mine has a low grade of some 1 .5 to 3 cpht but is highly economic as a result of its
unusually high average diamond price (US$2,131 per carat in 2018). Letseng accounts for some 30 percent of the
world market share of diamonds greater than 25 carats and has produced some of the biggest gem quality diamonds
recovered in the past number of years including the 910 carat Lesotho Legend, 603 carat Lesotho Promise, the 550
carat Letseng Star, the 493 carat Letseng Legacy and the 478 carat Light of Letseng. These are all Type IIa diamonds.
The Karowe Mine of Lucara Diamond Corp. has also produced some record Type IIa diamonds in the past few years,
notably 1,758 carat Sewelo, which is the second largest gem diamond ever recovered, the 1,109 carat L esedi La
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Rona, which is the third largest gem diamond ever recovered and sold for US$53 million, and the 813 carat
Constellation, which was sold for the record price of US$63.1 million.
Fourier Transform Infrared (“FTIR”) Spectrometry is used to determine the concentration and aggregation state of
nitrogen within the diamonds using industry standard methods. All analyses of nitrogen content and aggregation
state we re carried out at the SRC high security diamond facility, with 24 -hour video surveillance. The SRC ’s
Geoanalytical Laboratories is accredited to the ISO/IEC 17025 standard by the Standards Council of Canada as a
testing laboratory.
Senior Technical Advisor to Star Diamond, George Read, states: “The presence of a significant proportion of Type
IIa diamonds recovered in the Star Kimberlite by the Trench Cutter greatly increases the potential for the recovery
of large (plus 100 carat), high -value diamonds from a future mine . Analysis of the trench cutter diamond parcels
indicates a significant proportion of Type IIa diamonds, many of which are top white in colour with high value. The
presence of high -value diamond groups (Type IIa) greatly strengthens the future potential diamond pricing from
the Star Kimberlite.”
Star Diamond Corporation is a Canadian based corporation engaged in the acquisition, exploration and
development of mineral properties. Shares of the Corporation trade on the TSX Exchange under the trading symbol
“DIAM”. Star Diamond holds , through a joint venture arrangement with Rio Tinto Canada (a wholly -owned
subsidiary of Rio Tinto), a 25% interest in certain Fort à la Corne kimberlites (including the Star – Orion South
Diamond Project). These properties are located in central Saskatchewan, in close proximity to established
infrastructure, including paved highways and the electrical power grid, which provide significant advantages for
future mine development. Rio Tinto refers to their Fort à la Corne mineral properties as “Project FalCon”. During
2018, Star Diamond announced the positive results of an independent Preliminary Economic Assessment (the
“PEA”) on the Project. The PEA (on a 100% basis) estimated that 66 million carats of diamonds could be recovered
in a surface mine over a 38 -year Project life, with a Net Present Value (“NPV”) (7%) of $2.0 billion after tax, an
Internal Rate of Return (“ IRR”) of 19% and an after- tax payback period of 3.4 years after the commencement of
diamond production (see news release dated April 16, 2018).
All technical information in this press release has been prepared under the supervision of George Read, Senior
Technical Advisor to Star Diamond , a registered Professio nal Geoscientist in the Provinces of Saskatchewan and
British Columbia and Ma rk Shimell, Project Manager, a registered Prof essional Geoscientist in the Provin ce of
Saskatchewan, who are the Corporation’s “Qualified Persons” under the definition of NI 43-101.
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eferences (Available on Corporation’s website)
Bowen, D.C. Ferraris, R.D. Palmer, C.E. and Ward, J.D. (2009) On the unusual characteristics of the diamonds from
Letseng-la-Terae kimberlites, Lesotho. Li thos Vol. 112S pp.767 – 774.
Breeding, C.M. and Shigley, J.E. (2009) The “Type” classification system of diamonds and its i mportance in
gemology. Gems & Gemology Vol. 45 No. 2 pp. 96 – 111
Caution Regarding Forward-Looking Statements
This news release contains forward -looking statements as defined by certain securities laws, including the "safe harbour" provisions of
Canadian securities legislation and the United States Private Securities Litigation Reform Act of 1995. Forward -looking information is often,
but not always, identified by the use of words such as "anticipate", "believe", "expect", "plan", "intend", "forecast", "targ et", "project",
"guidance", "may", "will", "should", "could", "estimate", "predict" or similar words suggesti ng future outcomes or language suggesting an
outlook. In particular, statements regarding the Corporation's future operations, future exploration and development activities or oth er
development plans constitute forward-looking statements. By their nature, statements referring to mineral reserves, mineral resources, PEA
or TFFE constitute forward -looking statements. Forward-looking statements contained or implied in this press release include, but are not
limited to, the potential proportion of Type IIa diamonds in kimberlites located in the Fort à la Corne diamond district of central Saskatchewan,
Canada (which includes the Star, Orion South, Orion North and Taurus Kimberlites), diamond valuations and the potential for the recovery of
large high quality diamonds.
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These forward-looking statements are based on the Corporation's current beliefs as well as assumptions made by and information currently
available to it and involve inherent risks and uncertainties, both general and specific. Risks exist that forward-looking statements will not be
achieved due to a number of factors including, but not limited to, developments in world diamond markets, changes in diamond prices, risks
relating to fluctuations in the Canadian dollar and other cur rencies relative to the US dollar, changes in exploration, development or mining
plans due to exploration results and changing budget priorities of R io Tinto Canada or Star Diamond, the impact of changes in the laws and
regulations regulating mining explor ation, development, closure, judicial or regulatory judgments and legal proceedings, operational and
infrastructure risks and the additional risks described in Star Diamond's most recently filed Annual Information Form, annual and interim
MD&A.
Although the management of Star Diamond consider the assumptions contained in forward- looking statements to be reasonable based on
information currently available to them, those assumptions may prove to be incorrect. When making decisions with respect to Star Diamond,
investors and others should not place undue reliance on these statements and should carefully consider the foregoing factors and other
uncertainties and potential events. Star Diamond does not undertake any obligation to release publicly revisions to any forward -looking
statement to reflect events or circumstances after the date of this release, or to reflect the occurrence of unanticipated ev ents, except as
may be required under applicable securities laws. Investors should not assume that any lack of update to a previously issued forward-looking
statement constitutes a reaffirmation of that statement. Continued reliance on forward-looking statements is at investors’ own risk.
For further information: [email protected] or (306) 664-2202
www.stardiamondcorp.com
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