Mountain Province Diamonds Announces Leadership and Operational Update

TORONTO, Nov. 12, 2025 Mountain Province Diamonds Inc. (“Mountain Province”, the “Company”) (TSX: MPVD) (OTC: MPVD) today announces that the President & CEO Mark Wall, has resigned from the Company to pursue other opportunities.  Mark will remain with the Company until December 19, 2025, to ensure a smooth transition.

As reported in the Company news release of November 6, 2025 regarding the Company’s Q3 results, mining through the transitional phase of the high grade 5034-NEX orebody has commenced and this material is being processed.  In addition, the five -day plant maintenance shutdown was completed during Q3 and the Gahcho Kué mine (“GK Mine”) is now well positioned for strong performance in Q4 2025 and 2026.

The Board of Directors, together with its Nomination Committee, will commence a process to fill the role of President and CEO. The Company will provide an update in due course.

Jonathan Comerford, the Company’s Chairman, commented:

“On behalf of the Board, I would like to thank Mark for his substantial contribution to the Company and the operations of the GK mine over the past four years, during what has been a very challenging period for both the Company and the diamond industry as a whole. We wish him every success in his future endeavours.”

About Mountain Province Diamonds Inc.

Mountain Province is a 49% participant with De Beers Canada in the Gahcho Kué diamond mine located in Canada’s Northwest Territories. The Gahcho Kué Joint Venture property consists of several kimberlites that are actively being mined, developed, and explored for future development. The Company also controls more than 96,000 hectares of highly prospective mineral claims and leases surrounding the Gahcho Kué Mine that include an Indicated mineral resource for the Kelvin kimberlite and Inferred mineral resources for the Faraday kimberlites. Kelvin is estimated to contain 13.62 million carats (Mct) in 8.50 million tonnes (Mt) at a grade of 1.60 carats/tonne and value of US$63/carat. Faraday 2 is estimated to contain 5.45Mct in 2.07Mt at a grade of 2.63 carats/tonne and value of US$140/ct. Faraday 1-3 is estimated to contain 1.90Mct in 1.87Mt at a grade of 1.04 carats/tonne and value of US$75/carat. All resource estimations are based on a 1mm diamond size bottom cut-off.

For further information on Mountain Province Diamonds and to receive news releases by email, visit the Company’s website at www.mountainprovince.com.

Qualified Person

The disclosure in this news release of scientific and technical information regarding Mountain Province’s mineral properties has been reviewed and approved by Tom McCandless, Ph.D., P.Geo, and Tysen Hantelmann, P. Eng., independent advisors to the Company and Qualified Persons as defined by National Instrument 43-101 Standards of Disclosure for Mineral Projects.

NT4