VICTORIA, BRITISH COLUMBIA — 27 May 2026 — Southstone Minerals Limited (TSX-V:SML) (“Southstone” or the “Company”) reports diamond sales results from the Oena Diamond Mine in South Africa for fiscal Q3 2026 (March – May 2026), an operational update on production at the Oena Diamond Mine, and an update on the Company’s regulatory and corporate matters.
Q3 2026 Diamond Sales
The Company sold diamonds at three tenders during Q3 2026 – Tenders 275, 276 and 277. Aggregate Q3 2026 gross diamond sales were US$4,733,181 from 2,132.33 carats sold across 723 diamonds, at an average price of US$2,220 per carat. Each tender exceeded the ZAR 10,000,000 gross sales threshold in the Contract Mining and Diamond Recovery Agreement between African Star Minerals (Pty) Ltd. (“African Star”) and Rietput Delwery BK (“Rietput”), and the 80:20 Rietput:African Star revenue split (net of tender costs) applied to each tender. Southstone’s effective economic interest in net tender proceeds is 8.60%.
| Tender / Date | Carats Sold | Gross Sales (before tender costs) US ($) | Revenue Split Rietput : ASM | Effective SML Economic Interest | ZAR Split Trigger |
| 275 / Mar 19, 2026 | 491.33 | 1,196,470 | 80 : 20 | 8.60% | > ZAR 10M |
| 276 / Apr 23, 2026 | 551.66 | 882,328 | 80 : 20 | 8.60% | > ZAR 10M |
| 277 / May 21, 2026 | 1,089.34 | 2,654,383 | 80 : 20 | 8.60% | > ZAR 10M |
| Q3 2026 Total | 2,132.33 | 4,733,181 | — | — | — |
Table 1 – Q3 2026 tender results. Gross proceeds are stated before tender costs; revenue split applies to proceeds net of tender costs. Any minor inconsistencies are due to rounding.
Tender 277 delivered 17 single-stone Special diamonds (>10.8 carats) totalling 273.12 carats, with combined proceeds of US$1,663,238. The two largest stones were a 27.019 carat diamond which sold for US$248,248 and a 26.421 carat diamond which sold for US$145,541. Tender 277 also included an 8.233 carat fancy yellow diamond which sold for US$178,778, equating to US$21,715 per carat — the highest US$ per carat realised at the Oena Diamond Mine since the Company commenced production in 2015. Across Q3 2026 the Company sold 32 Special diamonds for combined proceeds of US$2,964,863, representing approximately 63% of Q3 2026 gross sales value.
Since the Company’s acquisition of Oena in 2015, cumulative gross diamond sales from the Oena Diamond Mine total US$28,370,761 from 15,464 carats sold across 6,729 diamonds at an average price of US$1,835 per carat.
Subsequent to Tender 277, production sorts on 24 and 25 May 2026 at the Sandberg S7 Basal section recovered an additional 434.55 carats, including nine Special diamonds (>10.8 carats) totalling 229.05 carats pending sale at the first tender of fiscal Q4 2026.
Operational Update — Oena Diamond Mine
Stripping for new pit. Mining at the Sandberg S7 Basal section of the Oena Diamond Mine, from which Q3 2026 production was derived, is approaching the limit of the current pit. The contract miner has advised that approximately six to eight weeks of overburden stripping will be required to open a new pit along strike before mining and recovery can resume in that area. During the stripping period, diamond recoveries are expected to be reduced.
Corporate Update
CC Mining Loan. On 22 May 2026, Southstone remitted the final payment of US$55,350.24 to CC Mining Limited under the loan agreement dated 29 January 2024 between the Company (as borrower) and CC Mining Limited (as lender) (the “Loan Agreement”). The final payment comprised US$54,569.15 of principal and US$781.09 of interest accrued at SOFR plus a margin of 8.00% per annum on an actual/365-day basis. Following this payment, all principal and interest under the Loan Agreement have been repaid and the Loan Agreement is to be discharged in accordance with its terms.
Director Appointment and Audit Committee. Effective 25 May 2026, Mr. Kevin Ma was appointed to the Board of Directors of the Company as an independent director and as Chair of the Audit Committee. The Board of Directors has determined that Mr. Ma is independent of the Company and of the management of the Company within the meaning of National Instrument 52-110 – Audit Committees, having considered all of his existing and recent relationships with the Company and concluded that none of them constitutes a material relationship that could reasonably be expected to interfere with the exercise of his independent judgment as a director. Mr. Ma is not an officer or employee of the Company or of any of the Company’s subsidiaries or affiliates, does not own or control, directly or indirectly, securities of the Company carrying more than 10% of the votes attached to the Company’s outstanding voting securities, and does not receive, directly or indirectly, any consulting, advisory or other compensatory fee from the Company other than in his capacity as a director and as Chair of the Audit Committee. Mr. Ma is a Chartered Professional Accountant (CPA, CA) and the principal of Calibre Capital Partners Corp., a Vancouver-based corporate finance advisory firm that advises public and private companies on governance and capital markets strategies. He concurrently serves as Executive Vice President, Chief Financial Officer and a Director of Kalo Gold Corp. (TSXV: KALO), and has held officer and director positions at a number of other publicly listed companies, with practical experience of TSX Venture Exchange requirements and continuous-disclosure obligations. Mr. Ma holds a Bachelor of Arts and a Diploma in Accounting from the University of British Columbia.
Following the appointment, the Board of Directors of the Company comprises Mr. Terry L. Tucker, Ms. Donna M. Moroney, Mr. Neil Budd and Mr. Kevin Ma, and the Audit Committee comprises Mr. Kevin Ma (Chair), Mr. Neil Budd and Ms. Donna M. Moroney.
Chief Financial Officer Appointment. Effective 25 May 2026, Mr. Derek Sobel of Catapult Consulting Corporation was appointed as Chief Financial Officer of the Company. Mr. Sobel has 15 years of experience in financial reporting, corporate modelling and financial audits, working with public and private companies primarily in the mining, resource and technology industries. Mr. Sobel has held Chief Financial Officer positions at a number of Canadian public companies and has been instrumental in their growth by building out robust financial reporting processes, implementing internal controls, developing internal budgeting and forecasting models, and streamlining day-to-day accounting processes. Mr. Sobel is a Chartered Professional Accountant (CPA, CA) and holds a Bachelor of Commerce degree from the University of Alberta.
The 25 May 2026 appointments of Mr. Sobel as Chief Financial Officer (separate from the Chief Executive Officer) and Mr. Ma as an independent director and Chair of the Audit Committee together address the deficiencies identified by the TSX Venture Exchange in its Notice to the Company dated 15 May 2025 (Submission #700966) under TSX Venture Exchange Policy 3.1 §5.7 (at least two Independent Directors), §5.8 and §5.9 (separation of CEO and CFO) and §21(b) (Audit Committee composition), subject to the filing of an Electronic Personal Information Form and Electronic Declaration on the TMX Portal for each of Mr. Ma and Mr. Sobel as new Insiders, which the Company expects to complete promptly.
Qualified Person Statement
The technical disclosure in this news release relating to diamond production, recovery and sales has been approved by Terry L. Tucker, P.Geo. (APEGBC), Executive Chairman, and a Qualified Person as defined by National Instrument 43-101. Mr. Tucker has verified the production and sales records disclosed in this release.
ON BEHALF OF SOUTHSTONE MINERALS LIMITED
Terry L. Tucker, P.Geo.
Executive Chairman
For additional information, please contact Terry L. Tucker at info@southstoneminerals.com
Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release. Capitalized terms used herein that have not been defined have the same meanings ascribed in the policies of the TSX.V.
Forward Looking Statements Disclaimer
Certain statements in this news release may constitute “forward-looking statements” within the meaning of applicable securities laws. Forward-looking statements are not historical facts and include, without limitation, statements regarding: the duration and outcome of overburden stripping for the new pit at the Sandberg section; the timing and cost impact of recent increases in South African diesel prices; the continued performance and renewal at expiry of the Contract Mining and Diamond Recovery Agreement with Rietput; the sustainability of recent average prices per carat and average diamond size at future tenders; the timing, scope and outcome of the renewal of Mining Right MPT24/2014MR over Oena; the timing, amount and acceptance of the rehabilitation guarantee top-up; the timing and outcome of the Section 102 amendment to the Environmental Management Programme and Mining Work Programme and the resulting Environmental Authorisation; ongoing compliance obligations under Water Use Licence 10/D82J/AG/16394; the maintenance of HDSA shareholding compliance and Reserve Bank exchange-control compliance at ASM; the timing and results of future tenders in fiscal Q4 2026; the discharge of the Loan Agreement following receipt of the final payment by CC Mining Limited; the filing of Electronic Personal Information Forms and Electronic Declarations on the TMX Portal for Mr. Ma and Mr. Sobel as new Insiders, and the subsequent acceptance by the TSX Venture Exchange of the cure of the Company’s previously disclosed non-compliance with TSX Venture Exchange Policy 3.1 described in this news release within the deadline of 12 September 2026 established by the Exchange’s letter dated 16 March 2026 under Submission #700966; the lifting of the trading halt of the Company’s common shares on the TSX Venture Exchange that has been in place since 10 January 2024; the Company’s ability to raise capital to fund the rehabilitation guarantee top-up, the mining right renewal process and ongoing working capital needs; and ongoing operations at the Oena Diamond Mine.
These risks and uncertainties include, among others, fluctuations in global diamond prices and market demand (including continuing weakness in the rough diamond market and competition from laboratory-grown diamonds); variations in the size, quality, quantity and price per carat of recovered diamonds (alluvial diamond production being inherently variable and a single tender or quarter not being a reliable predictor of future results); the absence of a current NI 43-101 technical report or independent mineral resource estimate for Oena; concentration of production at a single mining section and a single contract miner; contractor operational performance and the term of the Rietput Contract Mining and Diamond Recovery Agreement (expiring 30 January 2028); movements in the ZAR/USD exchange rate; the cost and availability of diesel fuel and other inputs in South Africa; the timing, terms and outcomes of regulatory consents, licences and approvals (including the mining right renewal, Water Use Licence compliance, the Section 102 EMP and MWP amendment, the Environmental Authorisation, the rehabilitation guarantee top-up and the Social and Labour Plan); the Company’s previously disclosed non-compliance with TSX Venture Exchange Policy 3.1 pending the filing of Electronic Personal Information Forms and Electronic Declarations for the new Insiders and TSX Venture Exchange acceptance of the cure described in this news release, and the continued trading halt of the Company’s common shares (in place since 10 January 2024); changes in South African mining, environmental, water, exchange-control or BBBEE legislation; the Company’s working capital deficiency and ability to raise capital to execute its business strategy; and the risks and uncertainties disclosed in the Company’s most recent Management’s Discussion and Analysis filed with Canadian securities regulators.
Readers are cautioned not to place undue reliance on forward-looking statements. Forward-looking statements are made as of the date of this news release, and the Company undertakes no obligation to update or revise them except as required under applicable securities laws.