HighGold Mining Inc. announced positive metallurgical test results for the Johnson Tract polymetallic Gold Project (Johnson Tract, JT or the Project) in Southcentral Alaska, USA. The Project hosts the high-grade Au-Zn-Cu-Pb-Ag JT Deposit with a 0.75moz gold equivalent (“AuEq”) indicated resource at 10.9 g/t AuEq and a 0.13moz AuEq inferred resource at 7.1 g/t AuEq. An updated and expanded mineral resource estimation for the JT Deposit is expected to be delivered before the end of the second quarter of 2022.

Highlights of Metallurgical Test Results: The polymetallic (Au-Zn-Cu-Pb-Ag) JT Deposit exhibits an excellent response using conventional metallurgical techniques. Locked cycle flotation tests yielded very high-quality copper, zinc, lead and gold concentrates produced at a coarse primary grind with very good metal recoveries, low impurities and negligible penalty elements. Highlights include: Gold recovery of97.2% combined total of payable gold to concentrates and leaching of tails; Zinc recovery of 92.3% to a concentrate grading 52.6% zinc; Copper recovery of 84.5% to a concentrate grading 30.6% copper; Lead recovery of 72.4% to a concentrate grading 62.1% lead; Gold pyrite concentrate grading 64.3 g/t gold; Coarse primary grind size of 125 microns.

Test Program Details: The metallurgical test program (the Program) was completed by Blue Coast Research Ltd. (BCR), a leading metallurgical testing and consulting firm based in British Columbia. The testwork was completed on a master composite sample (Master Composite) prepared from approximately 180 kg of ½ sawn HQ drill core from two dedicated holes, JT21-125 and JT21-134, drilled into the JT Deposit mineral resource in 2021. Sampled intervals included a blend from the upper and lower portions of the JT Deposit representative of the dominant mineralization styles present within the deposit.

The Master Composite has a head grade of 11.85 g/t gold, 6.2 g/t silver, 0.52% copper, 5.13% zinc, and 1.27% lead. The Program included mineralogical analysis, comminution testwork, flotation optimization testwork, locked cycle testwork, cyanidation of rougher tails and cleaner concentrates for global gold recovery, and follow-up mineralogical analysis of concentrates and tailings for deleterious elements. Discussion of Test Program Results: Mineralogy and Comminution: Mineralogical analysis of the Master Composite showed that primary sulphide minerals are sphalerite, pyrite, chalcopyrite and galena.

Pyrite, sphalerite and chalcopyrite all show very good liberation, with galena showing moderate liberation. Comminution testwork conducted on the Master Composite yielded the following results: Bond Ball Work Index of 16.6 kWh/tonne indicating the sample is hard; Bond Abrasion index testing results indicated the sample is moderately abrasive; SMC testwork showed that this sample was soft with respect to impact. Flotation; Flotation optimization was conducted on the Master Composite through a series of batch rougher and cleaner tests under a variety of conditions followed by a single locked cycle flotation test.

The parameters explored included: i) primary grind size; ii) lead and zinc depressants; iii) lead regrind; iv) gold/pyrite circuit; and v) an MF2 (Mill-Float x 2) flowsheet. The best flotation conditions were then applied to the locked cycle test. The locked cycle test was conducted as a standard six-cycle test.

The copper, lead and zinc circuits were conducted on all six cycles, and the gold circuit was added to cycle 6. A coarse primary grind of 125 microns was utilized, with flotation of a copper rougher concentrate reground and cleaned once, followed by flotation of a lead rougher concentrate reground and cleaned twice. The zinc rougher concentrate was cleaned once with no regrind. The gold circuit consisted of a secondary grind of the zinc rougher tails (MF2 flowsheet), followed by gold rougher, concentrate regrind, and gold cleaner float.

All concentrates met target grades for the metal of interest and recoveries were overall very good. Gold concentration is at payable levels for all concentrate products, including the zinc concentrate, with a majority reporting to the copper, lead and pyrite concentrates where pay-ability is highest. Low levels of deleterious elements and impurities were detected in the final concentrates and no penalties are expected for any of the concentrate products based on current smelter contract standards.