IsoEnergy Ltd.

Sample Collection Methods

IsoEnergy geologists and geological technicians complete or supervise the on-site collection of several types of samples from drill cores.

All drill core is systematically logged to record its geological and geotechnical attributes by IsoEnergy geologists and geological technicians. All drill core is systematically photographed and scanned for radioactivity with a handheld Radiation Solutions RS-125 spectrometer. IsoEnergy geologists mark sample intervals and sample types to be collected based on geological features in the core and on radioactivity measured with the RS-125 in counts per second (CPS). Geologists and geological technicians complete the on-site collection of several types of samples from drill cores.

Composite geochemistry samples consist of roughly one-centimetre-long chips of core collected every 1.5 m to geochemically characterize unmineralized sections of sandstone and basement. Composite sample lengths are between five and ten m (typically 3 to 7 chips per sample). A change to this procedure was made in 2024. For 5 m above and 2 m below the unconformity composite sample intervals are 0.5 m long.

Split-core “spot” (i.e., representative) samples are collected through zones of significant but unmineralized alteration and/or structure. Spot sample length varies depending on the width of the feature of interest but are generally 0.3 to 1.5 m in length; features of interest greater than 1.5 m are sampled with multiple samples. Half-metre shoulder samples are collected on the flanks of spot sample intervals.

Split-core mineralization (“MINZ”) samples are collected through zones of elevated radioactivity exceeding 350 CPS measured via RS-125 handheld spectrometer. MINZ samples are generally 0.5 m in length. One half of the core is collected for geochemical analysis while the remaining half is returned to the core box for storage on site. Intervals covered by MINZ samples are contiguous with and do not overlap intervals covered by composite samples. Density (“DENS”) samples are the only other type of sample collected from intervals covered by MINZ samples.

Split core density samples are collected from mineralized and unmineralized intervals. Within mineralized zones, density samples consist of a 0.1 m length of the half-core left after a MINZ sample is collected. Outside of mineralized zones density samples are commonly 0.1m long half-core samples with the other half returned to the box. Density samples are not routinely collected in exploration holes testing targets away from the Hurricane deposit on the Larocque East Project.

Systematic short-wave infrared (“SWIR”) reflectance (“REFL”) samples are collected from approximately the middle of each composite sample for analysis of clays, micas, and a suite of other generally hydrous minerals which have exploration significance. Spot reflectance samples are collected where warranted (i.e., fracture coatings). Reflectance samples are not collected through mineralized zones.

For lithogeochemistry samples, sample tags with the sample number are placed in the sample bags before they are sealed and packed in plastic pails or steel drums for shipment to the Saskatchewan Research

Council (“SRC”) in Saskatoon, Saskatchewan. A second set of sample tags with the depth interval and sample number are stapled in the core box at the end of each sample interval. A third set of sample tags with the drill hole number, sample depth interval, and sample number is retained in the sample book for archiving. SWIR reflectance samples are tagged in a similar fashion as lithogeochemistry samples.

Up to winter 2024, geologists entered all sample data into IsoEnergy’s proprietary drill hole database during core logging. Since the summer 2024 drilling program, logging and sampling data is being captured in MXDeposit, a commercially available software licensed from Seequent, and historic data has been migrated to MXDeposit.