Fort À LA Corne Project RIO Tinto Project Evaluation: Achievements and Confirmations
NEWS RELEASE May 27, 2024
Stock Symbol: DIAM: TSX Saskatoon, Saskatchewan
FORT À LA CORNE PROJECT
RIO TINTO PROJECT EVALUATION: ACHIEVEMENTS AND CONFIRMATIONS
SASKATOON, Saskatchewan, May 27, 2024 – Star Diamond Corporation (“Star Diamond”) is pleased to provide
a review of the work completed by Rio Tinto Exploration Canada Inc. (“RTEC”) on the Fort à la Corne Project
(“FalC Project”). From June 2017 until June 2022 , RTEC pursued extensive exploration and evaluation analysis
on two fronts at the FalC Project:
• The successful completion and calibration of a trench cutter bulk sampling and macrodiamond recovery
program on Star Kimberlite, with a view to expand this program to the Orion South Kimberlite; and
• A separate team of RTEC geologists conducted the Orbit exploration program, with the aim of
prioritizing the diamond prospectivity of all the other kimberlites that make up the FalC Project.
RTEC also conducted detailed mining studies for the future development of diamond mines on the Star, Orion
South and Orion North Kimberlites. Many of the conclusions of these mining studies confirm work previously
completed by Star Diamond.
Highlights of RTEC’s studies suggest:
• The continuous and sequential mining of diamonds from Orion South, Star and Orion North over a
period of seventy years;
• The ability to maintain stable pit slopes in the Fort à la Corne Kimberlites through the use of wall
buttressing and dewatering;
• Analysis produced by RTEC estimates that, based on the currently available size frequency distribution
(“SFD”) for the EJF kimberlite within the Star Kimberlite, a 222,000 tonne sample of the EJF is likely to
yield 101 Specials (+10.8 carats) and one Exceptional diamond (+100 carats); and
• RTEC confirmed that the TC EJF diamond parcel contained a significant proportion of Type IIa diamonds
(29% Type IIa +9 DTC).
Star Trench Cutter Bulk Sampling and Diamond Recovery
RTEC contracted Bauer Maschinen GmbH (“Bauer”) to adapt a Bauer BC 50 Cutter to sample kimberlite at
depths of up to 250 meters below surface. The trench cutter (“TC”) has a rectangular profile of 3.250 metres by
1.575 metres (3.200 by 1.525 metres drill tool plus 25 millimetres all round overbreak). The trenches were
excavated using the custom Bauer BC 50 Cutter mounted on a Bauer MC 128 Duty -cycle Crane. Kimberlite
excavated by the cutter bit was pumped to the surface in a slurry, and kimberlite fragments between +1.0 and
80.0mm were recovered from the slurry by the Kimberlite Separation Unit. These kimberlite fragments were
collected in cubic metre bulk bags and kept in an on- site storage area by RTEC until such time that they could
be processed through the newly constructed Consulmet Bulk Sampling Plant (“ BSP”). The BSP included a
modern diamond recovery flowsheet with a TOMRA XRT sorter to recover diamonds between 6.0 and 25.0mm
and a narrow range Dense Media Separator (“DMS”) to recover the small diamond s between 1.0 and 6.0mm.
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The BSP also included High Pressure Grinding Rolls (“HPGR”) to ensure liberation of +1 .0mm diamonds f rom
the +6.0-25.0mm waste from the XRT sorter.
RTEC successfully drilled ten TC holes in the Star Kimberlite and produced the total Early Joli Fou (“EJF”) diamond
parcel listed in the table below in comparison with EJF parcels produced from the previous Star Kimberlite
Underground and Large Diameter Drill (“LDD”) programs:
Diamond Parcels for Star Kimberlite EJF: TC, LDD and Underground
Star EJF
Kimberlite
Kimberlite
Tonnes
Carats
(+1 DTC)
Grade
(cpht)
Stones
(+1 DTC)
Stones per tonne
(+1 DTC)
Trench Cutter 8,964.71 1,428.89 15.94 24,900 2.78
LDD Inner 8,440.57 979.39 11.60 10,238 1.21
Underground 43,372.18 7,425.42 17.12 56,007 1.29
The TC EJF diamond parcel shows improved diamond grade over the LDD program and the TC grade is close to
that for the Underground. The significant increase in stones per tonne for the TC diamond parcel is a function
of the improved small diamond recovery by the modern flowsheet of the BSP. RTEC specifically designed this
BSP for the effective liberation of small stones by the HPGR and their efficient recovery as a result of the narrow
range (1.0-6.0mm) of the DMS. The small diamonds (+1DTC, +3DTC & +5DTC) of Star and Orion South are of a
high quality and colour and, consequently, have significant value: US$30 to US$50 per carat and opposed to the
usual US$5 to US$10 per carat. This efficient recovery of these small stones significantly improves the diamond
SFD and will add to the overall diamond grade for Star and Orion South in the pending revised Mineral Resource
estimate.
The TC E JF diamond parcel included 12 high value stone s ranging from 4.08 carats valued at US$5,100.00 to
16.96 carats valued at US$110,240.00. RTEC confirmed that the TC EJF diamond parcel contained a significant
proportion of Type IIa diamonds (29% Type IIa +9 DTC) and nine of the twelve most valuable stones are Type
IIa. The details of the high value TC diamonds and their Type IIa statistics were reported in News Release May
31, 2022
RTEC have documented that only Karowe Diamond Mine in Botswana and Letseng Diamond Mine in Lesotho
have similar coarse diamond SFD’s and proportions of Type IIa diamonds as that of the Star and Orion South
Kimberlites. The majority of +100 carat Exceptional diamonds mined globally are Type IIa and only two mines,
namely Karowe and Letseng, produce +100 carat Exceptional diamonds on a monthly basis. Two other diamond
mines, Cullinan in South Africa and Mothae in Lesotho, produce +100 carats Exceptional diamonds on an annual
basis. This poorly understood sub -population of Type IIa diamonds represents only 2 percent of global
production, yet dominate s the largest, highest value diamonds in the world. These diamonds have a unique
niche in the luxury goods market, which is usually not impacted by global uncertainty and certainly not by
synthetics. Specials, greater than 10.8 carats, and Exceptionals, with values in excess of US$10 million fill this
attractive niche, and the Star and Orion South Kimberlites, like Karowe and Letseng, can provide these unique
stones. Careful analysis produced by RTEC estimates that, based on the currently available SFD for the EJF
kimberlite within the Star Kimberlite, a 222,000 tonne sample of the EJF is likely to yield 10 1 Specials (+10.8
carats) and one Exceptional diamond (+100 carats). Remembering that the PEA anticipates an ore processing
rate of 45,000 tonnes of kimberlite per day and, consequently, Specials should be recovered on a daily basis
and Exceptional diamonds on a weekly basis.
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Orbit Exploration Program FalC Project
The results of the Orbit exploration program highlighted the kimberlites of Orion North (K120, K147, K148) as
having significant potential to add to the future Mineral Resources of the FalC Project. See recent Orion North
diamond valuation and Type IIa proportion News Release May 16, 2024 . Orion Centre (K145), Taurus (K150,
K118, K122) and K119 stand out in the field as having a number of the attributes sought but require further
work to completely evaluate . The methodology and conclusions of this work have already been published as
News Release April 13, 2022.
Mining Studies Completed by RTEC
RTEC developed a conceptual 74 year schedule for the sequential mining of Orion South, Star and Orion North,
assuming that the run-of-mine ore capacity was limited to 14 million tonnes per annum, and they anticipated
70 continuous years of kimberlite ore processing and diamond production. Star Diamond believes this work is
not necessarily compliant with NI 43-101.
Mining studies provided to Star Diamond by RTEC demonstrated the ability to maintain stable pit slopes in the
Fort à la Corne Kimberlites . I n addition, it was determined that the use of a mixed mining fleet improves
efficiency and brings forward time to first ore, specifically: the use of Bucket Wheel Excavators (“BWE”) in the
overburden along with in -pit crush and convey systems (“IPCC”) for delivery of ore to the processing plant,
combined with conventional truck and shovel in the ore zones. The use of BWE’s and IPCC has the potential to
lower the operating costs, along with a small mixed trucking fleet for buttressing which also allows for
operational flexibility. Correct scheduling allows longwall mining benches to be exploited within the confines of
a circular pit. BWE or IPCC (or combination) for overburden stripping and mining methods are electrically
powered and coupled with the accessib le provincial grid power, present a green er mining opportunity. Ultra-
class battery electric haul trucks are in development and can be integrated with BWE and IPCC.
RTEC mining studies confirmed that pit walls in the Lower Colorado Shale need to be minimized by leaving some
kimberlite in the pit wall, as this has a positive effect on stabilizing the pit slope. Buttressing is considered to be
a viable method of pit slope stabilization particularly within weak units in the pit walls, such as the Lower
Colorado Shale and paleo-channel units contained within some overburden areas. Dewatering of the Mannville
Group sediments is critical and has been proven as feasible and resolves stability in the base of the pits.
Depressurization of the Colorado Shale is key to achieving an acceptable Factor of Safety (“FoS”). Based on the
conceptual studies a FoS can be demonstrated at 1.3 for a pit with a pore pressure decrease of 50% above and
beyond unloading release. Once excavation begins and wall stability can be assessed at a bench scale,
performance-based design or observational mining has potential to further increase slope design angles.
Observational mining and performance -based design have been proven to successfully increase slope angles
against design in the Canadian oil sands.
George Read , Senior Vice President Corporate Development o f Star Diamond said: “ RTEC’s successful
development and execution of the TC sampling program and diamond recovery in the modern Consulmet BSP,
generated a diamond parcel that can be integrated with diamond parcels from previous underground bulk
sampling and LDD programs. The TC diamond parcel will improve the overall diamond grade and SFD used by
Star Diamond to estimate the revised Mineral Resou rce. RTEC’s Orbit exploration program has successfully
highlighted the Orion North kimberlite as a huge volume kimberlite containing a unique diamond population
with a coarse SFD and uniquely high proportion of Type IIa diamonds. RTEC’s mining studies suggest the
continuous mining of diamonds from the sequential mining of Orion South, Star and Orion North over a period
of seventy years.”
All technical information in this press release has been prepared under the supervision of George Read, Senior
Vice President Corporate Development, a registered Professional Geoscientist in the Provinces of
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Saskatchewan and British Columbia and Mark Shimell, Vice President Exploration, a registered Professional
Geoscientist in the Provinces of Saskatchewan and Alberta, who are Star Diamond’s “Qualified Persons” under
the definition of NI 43-101.
About Star Diamond Corporation
Star Diamond is a Canadian- based corporation engaged in the acquisition, exploration and development of
mineral properties. Shares of Star Diamond trade on the Toronto Stock Exchange under the trading symbol
“DIAM”. Star Diamond’s most significant asset is its 100% interest in the Fort à la Corne Project in central
Saskatchewan. These kimberlites are located in close proximity to established infrastructure, including paved
highways and the electrical power grid, which provide significant advantages for future mine development.
For further information, please contact:
Phone: (306) 664-2202
Email: [email protected]
Website www.stardiamondcorp.com
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Caution Regarding Forward-looking Statements
This press release contains "forward -looking statements" and/or "forward -looking information" (collectively, "forward -looking
statements") within the meaning of applicable securities legislation. All statements, other than statements of historical fact, are forward-
looking statements. Forward-looking statements in this press release include, but are not limited to, Star Diamond’s assessment of its
cost and management structure going forward.
These forward -looking statements are based on Star Diamond's current beliefs as well as assumptions made by and information
currently available to Star Diamond 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 diamo nd
markets, changes in diamond prices, risks relating to fluctuations in the Canadian dollar and other currencies relative to the US dollar,
changes in exploration, development or mining plans due to exploration results and changing budget priorities of Star Diamond, the
impact of changes in the laws and regulations regulating mining exploration, development, closure, judicial or regulatory judgments and
legal proceedings, operational and infrastructure risks and the additional risks described in Star Diamond's most recently fi led Annual
Information Form, annual and interim MDA.
For further information: [email protected] or (306) 664-2202
www.stardiamondcorp.com
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