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Star Diamond Corp
Symbol C : DIAM
Shares Issued 392,072,830
Close 2019-03-01 C$ 0.215
Recent Sedar Documents

Star Diamond typesets Star, Orion South diamonds

2019-03-04 08:51 ET - News Release

Mr. George Read reports

STAR - ORION SOUTH DIAMOND PROJECT SIGNIFICANT PROPORTIONS OF TYPE IIA DIAMONDS PRESENT AT STAR AND ORION SOUTH

Star Diamond Corp. has completed a major study into the abundance of Type IIa diamonds in the diamond parcels recovered from the Star and Orion South kimberlites located within the corporation's Star-Orion South diamond project, in the Fort a la Corne diamond district of central Saskatchewan, Canada, on mineral dispositions held 100 per cent by Star Diamond. This study confirms that unusually high proportions of Type IIa diamonds are present in both the Star (26.5 per cent) and the Orion South (12.5 per cent) kimberlites. This study confirms and augments an earlier study of Type IIa diamonds in the Star kimberlite (see news release dated June 9, 2010).

Type IIa diamonds are very rare and account for approximately less than 2 per cent of all natural rough diamonds mined from kimberlites. 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. While Letseng is a low grade (1.5 to three carats per hundred tonnes) kimberlite, it is probably the most prolific source of large high-value Type IIa diamonds, which contribute to making Letseng a highly economic deposit. The 2010 study on plus 2.7-carat diamonds from Star demonstrates that the Star kimberlite has a similar proportion of Type IIa diamonds to Letseng.

The Type IIa diamond counts and the percentage of Type IIa diamonds for the major Star and Orion South kimberlite units are documented in the attached table.

  
                   STAR KIMBERLITE (DIAMONDS +11 DTC (0.32 CARAT) TO +10.8 CARATS)

Geological unit             No. of diamonds typed   No. of Type IIa diamonds   Percentage Type IIa diamonds

Early Joli Fou (EJF) UG                     3,713                        986                           26.6
Pense (PPK) UG                                722                        205                           28.4
Cantuar (CPK) UG                              961                        240                           25.0
Total                                       5,396                      1,431                           26.5

                 ORION SOUTH KIMBERLITE (DIAMONDS +11 DTC (0.32 CARAT) TO +10.8 CARATS)

Geological unit            No. of diamonds typed     No. of Type IIa diamonds   Percentage Type IIa diamonds

Early Joli Fou (EJF) UG                    1,118                          125                           11.2
Early Joli Fou (EJF) LDD                     445                           66                           14.8
Pense (P2) UG                                309                           43                           13.9
Total                                      1,872                          234                           12.5
                             
UG (underground sample) 
LDD (large diameter drill sample)                                                          


  

As can be seen from the table, a significant number of diamonds, from each of the major kimberlite lithologies within both Star and Orion South, have been analyzed and typed. The diamonds analyzed represent a spectrum of diamond sizes from over 11 DTC (over 0.32 carat) through all of the large stones, up to diamonds of nearly 50 carats. The largest Type IIa diamonds identified include a 49.09-carat stone from Star and a 32.35-carat stone from Orion South. The most valuable of the Type IIa diamonds from Star is the 11.96-carat diamond valued at $11,333 (U.S.) per carat and the most valuable of the Type IIa diamonds from Orion South is the 15.88-carat diamond valued at $2,800 (U.S.) per carat.

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 10 of the largest known rough diamonds recovered worldwide, from the 726-carat Jonker to the 3,106-carat Cullinan.

The coarse diamond size frequency distribution for the Star kimberlite diamond populations (particularly the Cantuar and Early Joli Fou kimberlite units), combined with this significant proportion of Type IIa diamonds, strongly suggests the potential for the recovery of large (plus 100 carats), high-quality diamonds.

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 about 1.5 to 3 cpht but is highly economic as a result of its unusually high average diamond price ($2,131 (U.S.) per carat in 2018). Letseng accounts for about 30 per cent 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 the 1,109-carat Lesedi La Rona, which is the second largest gem diamond ever recovered, and the 813-carat Constellation, which was sold for the record price of $63.1-million (U.S.).

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 were carried out at the Saskatchewan Research Council's (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 vice-president of exploration and development, George Read, states: "The presence of a significant proportion of Type IIa diamonds in the Star and Orion South kimberlites greatly increases the potential for the recovery of large (plus-100-carat), high-value diamonds. Analysis of the Star and Orion South diamond evaluation parcels indicated a significant proportion of Type IIa diamonds, some of which are top white in colour. The presence of two high-value diamond groups (octahedra and Type IIa) greatly strengthens the future potential production diamond pricing from the Star and Orion South kimberlites."

Star Diamond is a Canadian-based corporation engaged in the acquisition, exploration and development of mineral properties. The corporation's Fort a la Corne kimberlites (including the Star-Orion South diamond project) 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 Exploration Canada Inc. (RTEC) refers to Star Diamond's mineral dispositions in the Fort a la Corne diamond district as Project FalCon.

All technical information in this press release has been prepared under the supervision of George Read, senior vice-president of exploration and development, a registered professional geoscientist in the provinces of Saskatchewan and British Columbia, and Mark Shimell, project manager, a registered professional geoscientist in the province of Saskatchewan, who are the corporation's qualified persons under the definition of National Instrument 43-101.

References (available on corporation's website)

D.C. Bowen, R.D. Ferraris, C.E. Palmer and J.D. Ward, J.D. (2009). On the unusual characteristics of the diamonds from Letseng-la-Terae kimberlites, Lesotho. Lithos volume 112S pages 767 to 774.

C.M. Breeding and J.E. Shigley (2009). The "Type" classification system of diamonds and its importance in gemology. Gems & Gemology volume 45 No. 2 pages 96 to 111.

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