Mr. Karl Hanneman reports

INTERNATIONAL TOWER HILL MINES ANNOUNCES PRE-FEASIBILITY STUDY RESULTS ON 13.6 MILLION OUNCE GOLD RESOURCE

International Tower Hill Mines Ltd. today released the results of the prefeasibility study (the PFS) for its Livengood gold project located near Fairbanks, Alaska. The PFS details a project that would process 65,000 tons per day and produce 6.4 million ounces of gold over 21 years from a gold resource estimated at 13.6 million ounces at 0.60 gram per tonne. The PFS utilized a third party review by Whittle Consulting and BBA Inc. to integrate new interpretations based on an expanded geological database, improved geological modelling, new resource estimation methodology, an optimized mine plan and production schedule, additional detailed metallurgical work at various gold grades and grind sizes, changes in the target grind for the mill, new engineering estimates, and updated cost inputs, all of which significantly derisk the project. The PFS has estimated the capital costs of the project (capex) at $1.93-billion (U.S.), the total cost per ton milled (opex) at $13.12 (U.S.), the all-in sustaining costs (AISC) at $1,171 (U.S.) per ounce, and an after-tax NPV (net present value)(5 per cent) of $400-million (U.S.) at $1,800/oz, $975-million (U.S.) at $2,000 (U.S.)/oz, and $2.3-billion (U.S.) at $2,500 (U.S.)/oz.

"This PFS confirms that the Livengood gold project is the one of the largest, highly leveraged gold projects in North America. This study is the culmination of years of work and greatly enhances our understanding of the deposit. We have now thoroughly evaluated, optimized and derisked all major elements of the project and have an excellent foundation on which to build shareholder value. International Tower Hill's estimated 13.6 million ounces, together with our favourable jurisdiction and proximity to infrastructure, offers our investors great leverage to the gold price," said Karl Hanneman, chief executive officer.

The company invites you to attend a conference call and webcast hosted by CEO Karl Hanneman to discuss the company and this news release.

Conference call and webcast details:

Date:  Nov. 5, 2021, at 12 p.m. ET

Webcast:  Chorus Call website

North American callers:  1-877-270-2148

International callers:  1-412-902-6510

Prefeasibility study overview

The project configuration evaluated in the PFS is a conventional, owner-operated surface mine that will utilize large-scale mining equipment in a blast/load/haul operation. Mill feed would be processed in a 65,000-ton-per-day comminution circuit consisting of primary and secondary crushing, wet grinding in a single semi-autogenous (SAG) mill and single ball mill followed by a gravity gold circuit, and a conventional carbon in leach (CIL) circuit.

Whittle enterprise optimization

Prior to beginning the PFS, the company retained Whittle Engineering and BBA Engineering to collaborate on an enterprise optimization study to review various technologies and project configurations and to recommend the optimum configuration for the PFS. The Whittle and BBA study reviewed secondary crushing with SAG and ball mill, tertiary crushing with ball mill, gravity/CIL at P80 of 90 micron to 250 micron, stand-alone and auxiliary heap leach configurations, gravity only gold recovery, gravity/flotation with pressure oxidation, and CIL of flotation concentrate. These configurations were evaluated at various combinations of project ramp-up strategy, annual throughput, primary, secondary and tertiary grind size, as well as mining fleet size and stockpile management strategies. Tailings technologies reviewed included conventional tailings and pressure filtered tailings.

The Whittle and BBA study determined that the gravity/CIL plant at P80 250 micron with conventional tailings provided the highest NPV, which is the configuration detailed in the PFS.

Prefeasibility study summary

The PFS was prepared by independent third party consultants and provides information on the optimized project with higher throughput, an updated resource estimate, and capital and operating cost estimates as compared with the project evaluated in the National Instrument 43-101 -- Standards of Disclosure for Mineral Projects April, 2017, technical report. The final version of the NI 43-101 technical report containing the PFS will be filed on SEDAR within 45 days. As a result of the changes to the project as evaluated in the PFS, including differences in the mineral resource estimation methodology and changes to the economic parameters applied to the geologic block model (gold price, recovery, capex and opex), all of which resulted in a change in the mineral resources, the project as evaluated in the 2017 report is no longer considered current and the 2017 report should therefore not be relied upon by investors.

The company cautions that the PFS is preliminary in nature, and is based on technical and economic assumptions which would be further refined and evaluated in a full feasibility study. The PFS is based on an updated project mineral resource estimate effective as of Aug. 20, 2021, using a different mineral resource model than what was used in the 2017 report.

The following is a summary of the material aspects and assumptions of the PFS. Investors are urged to review the complete NI 43-101 report following its filing on SEDAR for complete details of the PFS.

The engineering design to estimate capital costs used in the PFS are within a minus-20-per-cent/plus-25-per-cent accuracy.

Project location

The project is connected by an existing paved highway to the city of Fairbanks, 70 miles to the southwest in central Alaska. The project is located in an active mining district that has been mined for gold since 1914. The State of Alaska land use plan designates mining as the primary surface land use for the area in which the project is located. Employees would be bussed daily to the site from Fairbanks.

Infrastructure

The project would include a lined tailings management facility, an administration office/shop/warehouse complex, and would also include construction of a 50-mile 230-kilowolt electrical transmission line to the mine site from the existing grid power near Fairbanks, Alaska.

Environmental and community relations

Twelve continuous years of baseline environmental work continues to indicate that all aspects of the project can be successfully and safely managed. The design of the tailings facility incorporates best practices including a lined rock fill structure with a lined tailings basin. The project development team has considerable experience working with Alaska's large mine permitting process and has a proven and respected record of developing mining projects safely and in an environmentally sound manner. The project has already and will continue to provide local economic opportunities with local access to a highly skilled and available work force. The company is also working to seek early input on the project and to explore ways to maximize economic benefits to the local communities.

Gold price sensitivity analysis

The attached table shows the average annual free cash flow and EBIDTA (earnings before interest, taxes, depreciation and amortization) generated by the project at various gold prices.

The attached table shows the after-tax economics at various gold prices.

Capital costs

Key capital expenditures for initial and sustaining capital requirements are identified in the attached table.

Rounding of some figures may lead to minor discrepancies in totals.

All-in sustaining costs

The table below highlights the all-in sustaining costs and the all-in cost over the life of the project.

Annual gold production

The chart below highlights the anticipated production schedule. Total life-of-mine production is anticipated to be 6,430,178 ounces. Mill feed will consist of reclaimed ore from the low-grade stockpile during years 18 through 21.

Project mineral reserves

The table below presents the mineral reserve estimate for the project (effective as of Oct. 22, 2021). These proven and probable mineral reserves formed the basis of the economic evaluation of the project and are based on a gold price of $1,680 (U.S.) per ounce. The economic assumptions and parameters used for the calculation of reserves are the same as those used for the PFS financial model. Note that tonnages presented are in the metric system.

Livengood gold project mineral reserve estimate

Project mineral resources

The mineral resource estimates set forth in the PFS (2021 MRE) have been prepared by Resource Development Associates Inc. (RDA). Compared with the mineral resource estimates in the 2017 report, the 2021 MRE included spatial modelling of the occurrence of antimony throughout the deposit as well as modelling of the locations of massive stibnite veins within the deposit. These details add valuable contributions to the reasonable prospects of eventual economic extraction of gold for the project. Gold mineralization has been interpolated into 10 by 10 by 10 m blocks using inverse distance cubed (ID3) estimation techniques, believed to more conservatively support future production schedules as compared with the 2017 report, which was based on multiple indicator kriging of 15 by 15 by 10 m blocks parceled into 7.5 by 7.5 by 10 m selective mining units.

Mineral resources for the project were determined based upon a combination of 776 reverse circulation and diamond drill holes comprising 147,658 assays of which 125,450 assays measured detectable Au mineralization. High-grade Au outliers were capped prior to compositing. Assays were composited to nominal 10-metre lengths, yielding 20,806 individual samples which were used for the estimation of mineralization. Mineralization was determined using inverse distance cubed estimation techniques, adhering to geological constraints throughout the mineral deposit.

In order to define the quantities of Au with "reasonable prospects for economic extraction" by open pit methods, RDA determined pit constraining limits using the Lerchs-Grossmancopyright economic algorithm which constructs lists of related blocks that should or should not be mined. The final list defines a surface pit shell that has the highest possible total value, while honoring the required surface mine slope and economic parameters. Mineral resources were determined at a gold selling price of $1,650 (U.S.).

The parameters listed in Table 2 define a realistic basis to estimate the mineral resources for the project and are based on the extensive scientific, metallurgical and engineering based analyses that have been completed by Tower Hill Mines since 2006. Mineral resources for the project have been limited to mineralized material that occurs within the pit shells and which could be scheduled to be processed based on the defined cut-off grades. All other material within the constraining pit, which was not classified according to CIM Definition Standards, was characterized as non-mineralized material.

Grade and tonnage sensitivity to cut-off grade

Mineral resources at Livengood are sensitive to the selection of the reporting cut-off grade. To illustrate this sensitivity, the block model quantities and grade estimates within the constraining pit are presented in Table 3 at linear increases in the cut-off grades for measured, indicated and inferred mineral resources at Livengood. Mineralization is constrained to the pit using the parameters in Table 2. The numbers presented in Table 3 should not be misconstrued with a mineral resource statement. The figures are only presented to show the sensitivity of block model estimates to the selection of a cut-off grade. Mineral resources are not mineral reserves and do not have demonstrated economic viability.

Sensitivity of mineralization to gold price

The sensitivity of the Livengood project mineralization to the gold price was performed at selling prices of $1,320 (U.S.)/ounce (minus 20 per cent), $1,650 (U.S.)/oz (the 2021 MRE selling price) and $1,980 (U.S.)/oz (plus 20 per cent). The input technical parameters, defined in Table 2, were used in the analysis.

The mineral resource estimate for the project is inclusive of the mineral reserves for the project. Mineral resources that are not mineral reserves do not have demonstrated economic viability. Mineral resource estimates do not account for mineability, selectivity, mining loss and dilution. These mineral resource estimates include inferred mineral resources that are normally considered too speculative geologically to have economic considerations applied to them that would enable them to be categorized as mineral reserves. There is also no certainty that these inferred mineral resources will be converted to measured and indicated categories through further drilling, or into mineral reserves, once economic considerations are applied.

Metallurgy recovery by rock type

The company has completed extensive metallurgical test work on the rock types that comprise the current estimated mineral resource. Recovery rates by rock type using gravity and carbon-in-leach recovery of gravity tail are shown in the table below.

Detailed report

A NI 43-101 compliant technical report that summarizes the results of the PFS will be filed on SEDAR within 45 days of this news release and will be available on the company's website at that time.

Qualified persons

The PFS was prepared by the following qualified persons (as defined under NI 43-101), each of whom is independent of the company under NI 43-101, and each of whom has reviewed, verified and approved the scientific and technical data for which they have responsibility contained in this news release pertaining to the PFS. No limitations were imposed on the verification process.

Colin Hardie is a senior process engineer and the director of non-ferrous metal markets at BBA. He joined the BBA team in 2008 and has over 20 years of experience as an operations metallurgist, engineering consultant, and in process research and development. He is a graduate of the University of Toronto with a bachelor of applied science degree in geological and mineral engineering (1996). Mr. Hardie also has a master of engineering degree in metallurgy from McGill University (1999) as well as a master's degree in business administration from HEC Montreal (2008). He is a registered professional engineer in the province of Ontario, Canada. He has acted as a qualified person and lead study integrator for numerous North American gold, base metal and industrial mineral projects.

Jeffrey Cassoff is a senior mining engineer and the team leader for mining engineering at BBA. Mr. Cassoff has over 20 years of experience in the mining industry working for both mining operations and as a consultant. Mr. Cassoff is a graduate of McGill University with a bachelor of mining engineering (1999). Mr. Cassoff is a registered professional engineer in the province of Quebec, Canada. He has acted as a qualified person for numerous gold projects.

Melanie Turgeon is a process engineer at BBA and has worked in consulting engineering since 2013. She is a graduate of the Universite de Sherbrooke with a bachelor of chemical engineering (2011) and a registered engineer in the province of Quebec, Canada. She has been involved in the development of metallurgical testwork campaigns and in the writing of technical reports in accordance with standards governing NI 43-101.

Ryan T. Baker is a principal engineer with NewFields Mining Design & Technical Services LLC, located in Lone Tree, Colo. He is a graduate of Colorado State University with a bachelor of science degree in civil engineering (1993) and a registered professional engineer in Nevada (No. 13947), Alaska (No. 11172), Idaho (No. 10226), Colorado (No. 36988), Missouri (PE2008000049) and New Mexico (No. 22110). He is also a registered member of the Society for Mining, Metallurgy, and Exploration (SME, No. 4204584) and the American Society of Civil Engineers (ASCE, No. 307827) with relevant experience pertaining to heap leach, tailings and mine overburden storage facilities, and mine surface infrastructure design and inspection since 1994.

Michael Levy is geotechnical manager with JDS Energy & Mining Inc. in Denver, Colo. He is a graduate of the University of Iowa with a bachelor of science degree in geology and a master's of science degree in Civil-Geotechnical Engineering. He is a registered professional engineer with the states of Colorado (No. 40268) and a current member of the International Society for Rock Mechanics (ISRM) and the American Society of Civil Engineers (ASCE). Mr. Levy has practised for 22 years and has undertaken numerous mining and civil geotechnical projects ranging from conceptual through feasibility design levels, mine construction and operations support. He is skilled in both soil and rock mechanics engineering and specializes in the design and management of underground and open pit mine excavations.

Scott E. Wilson, CPG (10965), registered member of SME (4025107) and president of Resource Development Associates Inc., is an independent consulting geologist specializing in mineral reserve and resource calculation reporting, mining project analysis and due diligence evaluations. He is acting as the qualified person, as defined in NI 43-101, and is an author of the technical report which will be filed by the company for the mineral resource estimate and has reviewed and approved the mineral resource estimate and the PFS summarized in this news release. Mr. Wilson has over 32 years of experience in surface mining, resource estimation and strategic mine planning. Mr. Wilson is independent of the company under NI 43-101.

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