IsoEnergy Ltd.

Sampling Method

The primary assay data used in estimating Mineral Resources for the Tony M Mine is downhole radiometric logs.

Exploration drilling for uranium is unique in that core does not need to be recovered from a hole to determine the metal content. Due to the radioactive nature of uranium, probes that measure the decay products or “daughters” can be measured with a downhole gamma probe; this process is referred to as gamma logging. While gamma probes do not measure the direct uranium content, the data collected can be used along with probe calibration data to determine an equivalent U 3 O 8 grade in percent (%e U 3 O 8). Calculated equivalent U 3 O 8 grades are very reliable for uranium Mineral Resource estimation provided the values have been adjusted using a correction (±) factor for any disequilibrium that may occur in the area.

The disequilibrium correction factor is established by correlating the count rate obtained from the probe against chemical assay results and adjusting the probe count rates accordingly into equivalent % U 3 O 8 grades.

Century Wireline Services of Tulsa, Oklahoma (“Century Wireline”), a highly experienced borehole geophysical contractor logged all of the 2022 drill holes. The Tony M borehole geophysical logs collected natural gamma-ray, conductivity, and resistivity values continuously for each drill hole using a surface-recoding logging unit, and all data were plotted (analog) on log charts and entered into a digital database. Equivalent uranium grades (%e U 3 O 8) were calculated from the gamma-ray data by Century Wireline’s logging unit. The geophysical logging methodologies utilized by Century Wireline in the 2022 drilling program are consistent with those employed by previous operators of the Tony M Mine, and these methodologies are considered to be “industry standard” techniques for evaluation of sandstone-hosted uranium deposits.

Southwest Deposit

The original downhole gamma logging of surface holes was completed for the Southwest deposit by Century Geophysical Corp. (“Century”) and Professional Logging Services, Inc. (“PLS”) under contract to Exxon Minerals Company (“Exxon”). Standard logging suites included radiometric gamma, resistivity, and self-potential measurements, supplemented by neutron-neutron surveys for dry holes. Deviation surveys were conducted for most of the holes. The natural gamma, self-potential, and resistance were recorded on magnetic tape and then processed by computer to graphically reproducible form. The data was transferred from the tape to computer for use in resource estimation.

Assays of samples from core drilling were collected by company geologists and submitted to various commercial laboratories for analysis. Exxon used Core Labs, of Albuquerque, New Mexico, for at least some of this analytical work. Results of these analyses were compared to e U 3 O 8 values from gamma logs to evaluate radiometric equilibrium, logging tool performance, and validity of gamma logging.

Atlas Minerals Corporation (“Atlas”) prepared composite samples from Southwest deposit core recovered by Exxon for metallurgical testing. Testing completed included leach amenability studies, settling, and filtration tests.

Tony M Deposit

For the Tony M deposit, the same suite of logging surveys and procedures as employed by Exxon and Atlas was conducted on a majority of the holes. Most of the holes were logged by Century under contract to Plateau. Plateau also used PLS to log a small portion of the holes drilled in the mid-1980s. Deviation surveys were conducted for many of the holes. Neutron-neutron logging was conducted in some holes in this area providing information on rock characteristics. Assays of samples from core drilling were collected by company geologists and submitted for analysis to Skyline Labs, Hazen Research Inc., and Minerals Assay Laboratory, in addition to other commercial laboratories.

The initial logging by Century was completed using analog equipment. In 1978, Century’s CompuLog digital system replaced the analog equipment. At the time, Plateau conducted a series of comparative tests logging selected core holes with both types of equipment. The CompuLog results were found to be consistently 10% to 20% less than equivalent analog logs, however, the results were found to agree more closely with the results of chemical analyses of core from the logged holes.

Plateau contracted Hazen for metallurgical and analytical testing of samples from the Tony M deposit. This information was used to design the processing circuit for the Ticaboo Mill, which was constructed approximately four miles south of the portal of the Tony M Mine.

Confirmation assays of chemical % U 3 O 8 were completed on drill core samples for comparison and calibration with %e U 3 O 8 values from gamma logging. Plateau conducted a systematic program of analysis at independent commercial laboratories to confirm the reliability of results from its own analytical laboratory. For 2,354 analyses of radiometric and chemical uranium performed by the Plateau laboratory, 1,118 check analyses were performed on samples at independent commercial laboratories.

No drilling, logging, or core sampling was conducted by Energy Fuels or Denison and its predecessor IUC on the Tony M Mine.

The author of the Tony M Technical Report is of the opinion that historical work on the Tony M Mine was conducted using industry practice that was standard at the time.