Notes for Resource Table:

• The 2023 MRE is classified according to the CIM “Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines” dated November 29th, 2019 and CIM “Definition Standards for Mineral Resources and Mineral Reserves” dated May 10th, 2014.

• The 2023 MRE was prepared by Warren Black, M.Sc., P.Geo. and Tyler Acorn, M.Sc., of APEX Geoscience Ltd under the supervision of the QP, Michael Dufresne, M.Sc., P.Geo. in accordance with CIM Definition Standards.

• Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.  There has been insufficient exploration to allow for the classification of the indicated and inferred resources tabulated as a measured mineral resource; however, it is reasonably expected that the majority of the indicated and inferred mineral resources could be upgraded to measured or indicated mineral resources with continued exploration. There is no guarantee that any part of the mineral resources discussed herein will be converted to a mineral reserve in the future.

• All figures are rounded to reflect the relative accuracy of the estimates. Totals may not sum due to rounding. 

• Median rock densities are supported by 8,075 measurements applied: 2.95 g/cm3 (mineralized dolomite-carbonatite), 2.90 g/cm3 (unmineralized dolomite-carbonatite), 2.85 g/cm3 (mineralized xenolithic-carbonatite), 2.76 g/cm3 (unmineralized xenolithic-carbonatite), 2.73 g/cm3 (syenite), and 2.76 g/cm3 (limestone).

• The reasonable prospect for eventual economic extraction is met by reporting the Mineral Resources at a cut-off grade of 0.50% TREO (total rare earth oxide, sum of 10 oxides: CeO2, La2O3, Nd2O3, Pr6O11, Sm2O3, Eu2O3, Gd2O3, Tb4O7, Dy2O3 and Ho2O3), contained within an optimized open pit shell.

• The cut-off grade is calculated, and the open pit shell is optimized based on the assumption that the hydrometallurgical processing can produce mixed REE carbonate precipitates. The parameters utilized, as in the 2021 MRE, include the following considerations: 

  • TREO price: $18.66/kg

  • Exchange rate of 1.30 C$:US$

  • Precipitate production grades of 81.09% of TREO 

  • Processing costs include $21.47/t of mill feed for flotation plus a variable cost for hydrometallurgical plant that varies based on the feed grade. The average cost of hydrometallurgical plant is assumed to be $1,204/t of concentrate.  

  • Mining cost of C$2.00/t for mill feed and waste

  • G&A Costs of C$3.33/t for mill feed.

  • The overall process recoveries: For TREO>=2.3%, recovery is 69.6%; between 2.3% and 1.5% TREO, recovery is 65.3%; and less than 1.5% TREO, recovery is 52.2%. These assume variable flotation recoveries and a constant 87% hydrometallurgical recovery.

  • Overall pit slope angles vary by zone between 40 and 48 degrees.