Mr. Jason Kosec reports

INTEGRA ANNOUNCES UPDATED MINERAL RESOURCE ESTIMATE AT DELAMAR, INCLUDING THE ADDITION OF +500,000 OUNCES AUEQ (M&I) THROUGH SUCCESSFUL STOCKPILE DRILL PROGRAM

Integra Resources Corp. has released an updated mineral resource estimate (MRE) for the DeLamar and Florida Mountain deposits located in southwestern Idaho that incorporates the results from the highly successful stockpile drill program completed in April, 2023. The stockpile drill program added a measured and indicated (M&I) resource of 504,000 ounces (oz) gold equivalent (AuEq), and an inferred resource of 46,000 oz AuEq. The mineralized stockpile and backfill material that was incorporated into the updated DeLamar MRE demonstrates the potential for this material to significantly increase the heap leach mine life in future phases. The updated DeLamar MRE increased the total heap leachable oxide and mixed ounces within the M&I category by approximately 25 per cent, and increased the total inferred ounces by approximately 31 per cent. In total, approximately 90 per cent of the updated MRE falls within the M&I category, highlighting the quality and scarcity of projects such as DeLamar in the prolific Great basin mining district of the United States.

The company will host a webinar on Tuesday, Sept. 26, 2023, at 8 a.m. PT (11 a.m. ET) featuring a presentation from Jason Kosec, Integra's president, chief executive officer and director. Register for the webinar on-line.

Highlights:

• Including the 2023 DeLamar MRE, Integra now controls a total M&I resource of 6.2 million ounces (Moz) AuEq and a total inferred resource of 900,000 oz AuEq across its key projects located in Idaho and Nevada, representing one of the largest resource endowments in the Great basin of the U.S. not controlled by a major mining company.
• Stockpile and backfill resource update:
  • The maiden stockpile resource estimate contains an M&I resource of 504,000 ounces AuEq at 0.37 g/t AuEq, including 296,000 oz gold (Au) and 16.1 Moz silver (Ag), and an inferred resource of 46,000 oz AuEq at 0.30 g/t AuEq, including 26,000 oz Au and 1.5 Moz Ag.
  • The company allocated a total of approximately $4.6-million (U.S.) toward the stockpile drill program, which successfully resulted in the addition of more than 500,000 oz AuEq (M&I), representing the lowest discovery cost per ounce in the history of DeLamar.
  • A portion of the mineralized stockpile and backfill material was moved as a prestripping cost in the 2022 prefeasibility study (PFS), however this material is expected to be processed in future economic studies. The stockpile and backfill material is also expected to reduce the overall mining cost as the material is located at surface and was previously mined, reducing or eliminating additional blasting costs.
• Total DeLamar and Florida Mountain resource update:
  • The total DeLamar M&I resource contains 4.8 Moz AuEq at 0.60 g/t AuEq, including 2.9 Moz Au and 142.7 Moz Ag.
  • The total DeLamar inferred resource contains 621,000 oz AuEq at 0.45 g/t AuEq, including 428,000 oz Au and 15 Moz Ag.
• Oxide-mixed heap leach resource update:
  • The oxide and mixed heap leach portion of the M&I resource contains 2.6 Moz AuEq at 0.50 g/t AuEq, including 1.6 Moz Au and 73.9 Moz Ag.
  • The oxide and mixed heap leach portion of the inferred resource contains 284,000 oz AuEq at 0.36 g/t AuEq, including 199,000 oz Au and 6.6 Moz ounces Ag.
  • The significantly increased oxide and mixed resource at DeLamar demonstrates the potential for an extended heap leach mine life in future phases of operations.
• The company anticipates filing the mine plan of operations (MPO) for DeLamar in Q4 2023, making DeLamar one of the only precious metal development projects in the Western United States that is actively being advanced toward a production permit.

Note: AuEq equals Au plus (Ag divided by 77.7).

Jason Kosec, Integra's president, chief executive officer and director, commented: "We are extremely proud of our entire team for the combined effort that delivered the DeLamar MRE on time and above expectations. The updated MRE at DeLamar represents a significant milestone for the company and further solidifies Integra's position as an industry-leading exploration and development company focused in the Great basin. The highly successful stockpile drill program and subsequent MRE have increased the oxide and mixed M&I resource at DeLamar by approximately 25 per cent, validating the company's belief that the mineralized stockpile and backfill material at surface has the potential to significantly expand the heap leach mine life in future phases of operations. This mineralized material, a portion of which was included as a prestripping cost in the company's 2022 PFS, is expected to provide important operational flexibility for the potential heap leach operation. The company has begun optimization work on the mineralized stockpile material to evaluate its potential inclusion in future phases of heap leaching at DeLamar, which will be formally included in a feasibility study expected to be released in late 2024 or early 2025. The focus of the team now shifts to finalizing the MPO for DeLamar, which will be submitted in Q4 2023, representing another important step toward the company's vision of becoming a leading U.S.-focused gold and silver producer."

The mineral resource estimate has been reported in accordance with National Instrument 43-101 -- Standards of Disclosure for Mineral Projects and was prepared by Mine Development Associates, a division of Respec of Reno, Nev., with an effective date of Aug. 25, 2023.

Mineral resource estimation overview:

• The gold and silver MRE at DeLamar were modelled and estimated by Michael Gustin of Respec, an independent qualified person as defined in NI 43-101. Mr. Gustin evaluated the drill data statistically, separately interpreting gold and silver mineral domains on sets of 30 m spaced cross-sections. Analysis was completed on the modelled mineralization spatially and statistically to aid in the establishment of estimation and classification parameters, interpolating grades into a three-dimensional block model using 3-D gold and silver mineral domains to constrain the estimation (inverse distance cubed). Mineral resources were constrained to lie within resource pit shells, then classified based on geometrical and statistical parameters.
• The oxide, mixed and non-oxide material was modelled in 3-D using both geological and analytical data (cyanide solubility checks). Different recoveries and economical parameters were applied to each of these oxidation domains.
• The reported MRE has been constrained within optimized pit shells using a gold price of $1,800 (U.S.)/oz Au and a silver price of $21 (U.S.)/oz Ag. These metal prices, as well as the metal recoveries summarized herein, were used to calculate gold equivalent cut-off grade and contained ounces.
• Geotechnical pit slope angle varies per rock type between 30 degrees and 45 degrees.
• Additional inputs for Whittle pit-optimization include: mining costs from $1.70 (U.S.) to $2 (U.S.)/tonne mined; heap leach costs from $3 (U.S.) to $5 (U.S.)/tonne; milling costs from $9.75 (U.S.) to $16.75 (U.S.)/tonne; and general and administrative costs of 40 U.S. cents/tonne processed.
• Recoveries for the MRE are as follows:
  • DeLamar in situ recoveries: heap leach oxide -- 90 per cent/40 per cent for Au/Ag; heap leach mixed -- 70 per cent/50 per cent for Au/Ag;
  • Florida Mountain in situ recoveries: heap leach oxide -- 90 per cent/55 per cent for Au/Ag; heap leach mixed -- 75 per cent/60 per cent for Au/Ag.
  • North DeLamar stockpile recoveries: heap leach -- 70 per cent/60 per cent for Au/Ag; stockpile 1 heap leach recoveries: 80 per cent/50 per cent for Au/Ag; stockpile 2 heap leach recoveries: 80 per cent/55 per cent for Au/Ag; Jacobs Gulch stockpile and Florida Mountain backfill recoveries: 90 per cent/45 per cent for Au/Ag.
  • Glen Silver in situ non-oxide recoveries: 78 per cent/78 per cent for Au/Ag; milestone in situ non-oxide recoveries: 70 per cent/75 per cent for Au/Ag; other mill areas in situ non-oxide recoveries: 87 per cent/87 per cent for Au/Ag; Florida Mountain in situ non-oxide recoveries: 95 per cent/92 per cent for Au/Ag.
• The MRE is based on 372,888 metres in 3,185 drill holes, either drilled by Integra or previous owners.
• In 2022, Integra initiated the stockpile drill campaign, which concluded in April, 2023. In total, the company drilled 12,588 m in 321 drill holes using both reverse circulation and sonic drills. The drill campaign covered approximately 80 per cent to 90 per cent of the 60 million tonnes of mineralized stockpiles and backfill. The remaining tonnes of mineralized stockpiles and backfill were not drilled primarily due to safety concerns related to winter weather. The company believes that the remaining tonnes can be drilled in the future and converted into resources.
• A technical report on the MRE will be prepared in accordance with NI 43-101 and will be filed within 45 days of this news release on Integra's issuer profile on SEDAR+.
• The results of the PFS on DeLamar included in the technical report titled "Technical report and preliminary feasibility study for the DeLamar and Florida Mountain gold-silver project, Owyhee county, Idaho, U.S.," dated March 22, 2022, with an effective date of Jan. 24, 2022, remains unaffected by this MRE update and will be included in the technical report for the MRE that will be available under the company's profile at SEDAR+ within 45 days of this news release.

Next steps

The company is focused on continuing to advance the DeLamar project, and the Wildcat and Mountain View projects, and expects to complete the following key catalysts in the near term:

• DeLamar and Florida Mountain projects in southwestern Idaho:
  • Submit the MPO to the United States Bureau of Land Management in Q4 2023. The MPO is the first significant step in the National Environmental Policy Act permitting process as it represents the proposed action for the project.
  • Bottle roll analysis from all areas tested during the stockpile drill program is under way and at least one column leach test from each of the six stockpile/backfill locations is expected to start before year-end.
  • Complete a feasibility study in late 2024 or early 2025 which will incorporate a portion of the mineralized stockpile/backfill material into a mine plan, demonstrating the potential for this material to increase the heap leach mine life at DeLamar in future phases of operation, and further enhance the robust economics presented in the 2022 PFS.
• Wildcat and Mountain View projects in western Nevada:
  • Initiate an exploration program at Wildcat upon receipt of the exploration plan of operations, which will increase the surface disturbance area from five acres to 400 acres.
  • Initiate baseline studies at Wildcat in H1 2024, in anticipation of a feasibility study and the filing the of the MPO in 2025.

Stockpile drill program

The stockpile drill program was designed to test a large portion of the approximately 49 million tonnes of mineralized material at the DeLamar deposit and 11 Mt of mineralized material at the Florida Mountain deposit. This mineralized material was blasted and mined by previous operators, and either stockpiled or used as backfill because the material fell below the mill cut-off grade. The stockpile drill program was executed at nominal 60 m collar spacings with select 30 m infill test holes to further verify grade and variability. All drilling was vertical through the entirety of the stockpiles and backfill material. The drilling was conducted by a combination of sonic and reverse circulation with casing advance drilling methods. Both these drilling methods were chosen to maintain high sample quality and integrity throughout the drilling process. Additionally, the two drilling methods provided a basis for continuity comparison. Sampling was conducted at 1.5 m intervals for the whole of the drilling program, with all samples sent to a certified third party lab for analysis.

Sampling and quality assurance/quality control (QA/QC) procedure

Thorough QA/QC protocols are followed on the project, including insertion of duplicate, blank and standard samples in the assay stream for all drill holes. The samples are submitted directly to American Assay Labs in Reno, Nev., for preparation and analysis. Analysis of gold is performed using fire assay method with atomic absorption finish on a one-assay-ton aliquot. Gold results over five g/t are rerun using a gravimetric finish. Silver analysis is performed using ICP (inductively coupled plasma) for results up to 100 g/t on a five-acid digestion, with a fire assay, gravimetric finish for results over 100 g/t silver.

Additional supporting details regarding the information in this news release will be provided in the MRE technical report, which will be available on SEDAR+ under the company's profile within 45 days of this news release, including all qualifications, assumptions and exclusions that relate to the MRE. The MRE technical report is intended to be read as a whole, and sections should not be read or relied upon out of context.

Qualified persons

The scientific and technical information contained in this news release has been reviewed and approved by Raphael Dutaut, PhD, PGeo, Integra's vice-president of exploration, and Tim Arnold, PE, SME, Integra's chief operating officer. Both individuals are qualified persons (QP) as defined in National Instrument 43- 101 -- Standards of Disclosure for Mineral Projects.

Michael Gustin, CPG, of Mine Development Associates, a division of Respec of Reno, Nev., is an independent qualified person as defined by NI 43-101, and has reviewed and approved the contents of this news release.

DeLamar project overview

The past-producing DeLamar project, which includes the adjacent DeLamar and Florida Mountain gold and silver deposits, is located in Owyhee county in southwest Idaho. Since acquiring the project in 2017, the company has demonstrated significant resource growth and conversion, while providing robust economic studies in its maiden preliminary economic assessment and PFS. An independent technical report for the MRE on the DeLamar project, prepared in accordance with the requirements of NI 43-101, will be available under the company's profile at SEDAR+ within 45 days of this news release.

About Integra Resources Corp.

Integra is one of the largest precious metals exploration and development companies in the Great basin of the Western United States. Integra is currently focused on advancing its three flagship oxide heap leach projects: the past-producing DeLamar project located in southwestern Idaho, and the Wildcat and Mountain View projects located in western Nevada. The company also holds a portfolio of highly prospective early-stage exploration projects in Idaho, Nevada and Arizona. Integra's long-term vision is to become a leading United States-focused mid-tier gold and silver producer.

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