The baseline estimation and classification of the mineral resources was completed in 2009 by AMEC and summarized in the “Gahcho Kué Kimberlite Project NI 43-101 Technical Report” (AMEC 2009). Additional drilling at Tuzo undertaken in 2012 added to the AMEC mineral resource the Tuzo Deep mineral resource more than 300 metres below surface (mbs) elevation as summarized in the “Update of the Mineral Resource Estimate for the Tuzo Kimberlite, Gahcho Kué Project, Northwest Territories, Canada NI 43-101 Technical Report” by Mineral Services in 2013. The baseline resource by AMEC and the Tuzo Deep Resource by Mineral Services were compiled by JDS Energy & Mining Inc. for the 2014 Gahcho Kué Technical Report and Feasibility Study. The estimation and classification of the mineral resources were further updated by JDS to reflect operations as of 2019 (2020 Gahcho Kué Mine NI 43-101 Technical Report, NWT, Canada). In mid-2024 an updated estimate of mineral resources was completed by JDS. All of the NI 43-101 reports can be found under the company name on www.sedar.com, with the most recent ones also provided in the website links below.

Updated Mineral Resource and Reserve estimates have since been generated by De Beers as operating partner of the Gahcho Kué Mine as at the end of December 2024. These estimates are provided in the summary tables below.

The Hearne Northwest Extension was discovered during routine mining activities in late 2021. A significant amount of core drilling was conducted to determine the volume extent of the extension. The drill results were used to generate a target for further estimation (‘TFFE’) on the Hearne Northwest Extension. This is provided in the table below. The estimate of TFFE is conceptual in nature as there has been insufficient exploration to define a Mineral Resource, and it is uncertain if future exploration will result in the estimate being delineated as a Mineral Resource. Further core drilling and assessment of the core following the protocols described above will be required to increase confidence above a TFFE.

An economic viability study of the deeper kimberlite at Hearne, NEX and Tuzo was conducted to extend the life of mine through underground mining. The study indicated a marginally positive business case model. Further studies in support of the mine life expansion through underground development ceased in 2024. Exploration for underground expansion may be revisited with improved economic conditions. but with the end of mine life in 2031, any further work would require lead-time before then to avoid a gap in ore production.

Indicated and inferred mineral resource estimates have been determined for the Kelvin and Faraday kimberlites, respectively. Geological model domains for the Kelvin, Faraday 2 and Faraday 1-3 kimberlites were adopted as the resource domains for the estimation of the Mineral Resources. The volumes of these domains were combined with estimates of bulk density to derive tonnage estimates. Bulk sampling programs using large diameter RC drilling were conducted to obtain grade and value information. Microdiamond data from drill core were used to forecast grades for the different kimberlite lithologies. Details of the modeling are available in NI 43-101 Compliant Technical Reports (filed in 2016 and 2017 under Kennady Diamonds Inc.) and the NI 43-101 Compliant Technical Report filed April 11, 2019 under Mountain Province Diamonds. All reports are available below and at www.sedar.com.  A summary of the estimated resources is provided in the table below (as of April, 2019).

• Mineral Resources are reported at a bottom cut-off of 1.0 mm. Incidental diamonds are not incorporated in grade calculations.
• Mineral Resources are not mineral reserves and do not have demonstrated economic viability.

Gahcho Kue Mine NI 43-101 Technical Report - October 2 2024
Gahcho Kue Mine NI 43-101 Technical Report - March 28 2022
Gahcho Kue Mine NI 43-101 Technical Report - March 1 2020
Gahcho Kue Mine NI 43-101 Technical Report - March 16 2018
Gahcho Kue Mine NI 43-101 Technical Report - March 31 2014

Kennady North Project NI 43-101 Technical Report - May 10 2019
Kennady North Project NI 43-101 Technical Report - November 16 2017
Kennady North Project NI 43-101 Technical Report - January 24 2017