Ms. Ute Koessler reports

TREVALI ANNOUNCES POSITIVE FEASIBILITY STUDY FOR POTENTIAL ROSH PINAH EXPANSION "RP2.0"

Trevali Mining Corp. has released positive results from the Rosh Pinah expansion RP2.0 National Instrument 43-101 feasibility study at its 90-per-cent-owned Rosh Pinah mine in Namibia. All figures in this release are stated in U.S. dollars on a 100-per-cent ownership basis.

Highlights of the FS include:

• Planned 86-per-cent increase in mill throughput from 700,000 tonnes per annum to 1.3 million tonnes per annum;
• Assuming a positive investment decision:
  • Detailed engineering and procurement of long-lead items expected to commence in fourth quarter 2021, with construction expected to commence midyear 2022;
  • Commercial production expected around midyear 2024;
• Incorporates previously announced 15-year solar power purchase agreement with EMESCO (Emerging Markets Energy Services Company) for the supply of solar power of approximately 30 per cent of the required power;
• Addition of a water treatment plant in conjunction with the paste fill plant anticipated to reduce water intensity of the operation from 1.54 cubic metres per tonne to 0.65 cubic metre per tonne of ore processed;
• Production and operating costs (postcommercial production):
  • Average annual zinc payable production: 135 Mlb;
  • Average AISC (1): 67 cents per lb;
  • Average annual lead and silver payable production: 23.7 Mlb and 303 Koz, respectively;
• Proven and probable mineral reserves:
  • 12.35 million tonnes containing 1,744 Mlb of zinc, 370 Mlb of lead and 7,858,000 ounces of silver;
• Project capital expenditures of $111-million:
  • Modifications to the existing process plant to include a single-stage SAG (semi-autogenous grinding) mill, crushing and ore blending area, increased zinc and lead flotation circuit capacity;
  • Addition of a paste fill plant and reticulation system including a water treatment plant;
  • Dedicated portal and decline to the WF3 deposit with new material-handling system;
  • Mine surface and underground infrastructure;
• Project economics (after tax) using $1.17 per lb zinc, 96 cents per pound lead and $24.47 per ounce silver price assumptions:
  • Net present value discounted at 8 per cent: $156-million;
  • Free cash flow: $290-million;
  • Internal rate of return: 58 per cent;
  • Payback period: 4.6 years.

(1) All-in sustaining cost (AISC) and C1 cash costs are non-international financial reporting standard performance measures. See "Use of Non-IFRS Financial performance Measures" in the company's management's discussion and analysis for the three and six months ended June 30, 2021, dated Aug. 4, 2021, and filed on SEDAR for further information regarding these measures.

Ricus Grimbeek, president and chief executive officer, commented: "Since providing the results of the expansion prefeasibility study in August, 2020, the team has optimized and derisked the project, delivering a feasibility study that reaffirms robust project economics, while reducing our carbon intensity and water consumption usage on a per tonne milled basis. The RP2.0 project will modernize and expand the 50-year-old mine, increasing throughput by 86 per cent and enabling the operation to increase production at a significantly lower operating cost, all while working more safely and reducing our environmental footprint.

"In parallel with advancing the technical aspects of the project, we have had productive discussions with our existing lending syndicate, as well as numerous financial institutions, on securing project debt financing to minimize equity dilution."

Rosh Pinah expansion RP2.0 feasibility study

Processing plant: The FS incorporates a planned upgrade to the comminution circuit to include a new, single-stage SAG mill and pebble crusher. The expansion also includes primary crushing upgrades and an ore blending area, along with other circuit modifications intended to provide increased flotation, thickening, filtration and pumping capacity to achieve the target throughput of 1.3 Mtpa. The upgrade will also include several flowsheet modifications aimed at improving both the concentrate grade and metal recoveries.

Underground development and infrastructure: A dedicated portal and decline to the WF3 deposit will be constructed to support the increase in mine production levels and to reduce operating costs. The planned trucking decline is 3.9 kilometres in length, excluding level access and stockpiles. The trucking decline will act as an additional fresh air intake within the ventilation network and will enable direct ore haulage from the WF3 zone to a new surface primary crusher station, utilizing large-scale (60-tonne) trucks. Ore sourced from other areas (EOF, SF3, SOF and BME) will be transported to the existing underground crushing system using the existing 30-tonne truck fleet and conveyed to surface through the existing conveying system.

Paste fill plant: A paste fill plant designed to operate at both the current 700,000 tonne per annum and the 1.3 Mtpa targeted throughput rate has been included. Paste filling the stopes rather than leaving them void is expected to improve ground stability, increase ore recovery and reduce dilution, and also to reduce surface tailings as a portion of new tailings will be redirected underground to be used as paste fill. A water treatment plant has been added to the paste fill plant system, which is expected to significantly reduce water consumption. The system in conjunction with the paste fill plant system is anticipated to reduce the water intensity of the Rosh Pinah operation from 1.54 cubic metres per tonne to 0.65 cubic metre per tonne of ore.

Mobile equipment: The existing, small-scale underground truck and load haul dump (LHD) fleet will continue to be used primarily in the current mining areas. As mining extends deeper and average haulage distances increase in WF3, new large-scale trucks and LHDs are planned to be purchased for the more efficient transportation of material to surface, which is expected to reduce costs over the life of mine.

Renewable solar energy power purchase agreement: Trevali has entered into a 15-year power purchase agreement (the PPA) with Emerging Markets Energy Services Company. The PPA with EMESCO is anticipated to deliver 30 per cent of Rosh Pinah's power requirements during the life of the agreement. EMESCO will be responsible for the design, permitting, financing and implementation of a solar energy system on a neighbouring property at no cost to Trevali. EMESCO will sell the power generated to Trevali at a fixed rate that is expected to reduce energy costs by 8 per cent over the 15-year term of the agreement.

On-site operating costs: Once the project is commissioned, on-site operating costs are expected to reduce by approximately 26 per cent on a per tonne milled basis. Mining costs per tonne milled are expected to be reduced due to the planned change in the mining method to include paste fill, allowing for increased ore recovery and reduced mining dilution. Mining costs are also expected to benefit from the dedicated underground decline to the WF3 deposit, which should allow for more efficient material handling and reduced cycle times. The processing unit costs are expected to decrease as a result of treating increased tonnages following the upgrade. Fixed on-site costs on a per tonne milled basis are also expected to decrease as the mine ramps up from 700,000 tonnes per annum to the FS target of 1.3 Mtpa as a function of higher annual throughput.

Life of mine and RP2.0 FS expansion economics

Expansion capital cost summary in millions of U.S. dollars

(2) As of effective date of March 31, 2021.

Zinc price sensitivity estimates

Mineral resources and reserves

The mineral resource estimate for the Rosh Pinah deposit covers numerous lenses. A total of seven mineral lenses are included in the updated mineral resource estimate as of March 31, 2021.

To convert mineral resources to mineral reserves, mining cut-off grades were applied, mining dilution was added and mining recovery factors were assessed. Only measured and indicated mineral resources were used for mineral reserve estimation.

A cut-off value of $50 (U.S.) per tonne was used to report the mineral reserves. The selected cut-off value is above the projected full break-even cut-off value.

Updated mineral resource and mineral reserve estimates are planned as part of the company's annual year-end process. The conversion of additional resources and further optimizations may be included in this process, which, if included, will further enhance the project's economics. For further information regarding the mineral resource and mineral reserve estimate, please see the FS dated Aug. 16, 2021, and filed on the company's SEDAR profile.

Mineral resources

Notes:

• CIM (Canadian Institute of Mining, Metallurgy and Petroleum) definition standards for mineral resources and mineral reserves (2014) were used for reporting of mineral resources.
• The mineral resources are stated inclusive of mineral reserves.
• Mineral resources are reported at a 4-per-cent zinc equivalent cut-off grade, which approximates a net smelter return value of $40 (U.S.) per tonne.
• Zinc equivalency was estimated as ZnEq equals Zn (per cent) plus Pb (per cent) plus [Ag (gram per tonne) times 0.028)].
• Effective date of mineral resources is March 31, 2021.
• The qualified person for the mineral resource estimate is Rodney Webster, MAIG, of AMC.
• Totals may not compute exactly due to rounding.
• Mineral resources are stated on a 100-per-cent ownership basis.

Mineral reserves

Notes:

• CIM definition standards for mineral resources and mineral reserves (2014) were used for reporting of mineral reserves.
• Mineral reserves were estimated at a full break-even net smelter royalty cut-off value of $50 (U.S.) per tonne.
• NSR values were calculated based on average metal prices of $1.17 (U.S.) per pound Zn, 96 U.S. cents per lb Pb and $24.47 (U.S.) per oz Ag.
• The average processing recoveries used were 88.8 per cent for zinc, 68.5 per cent for lead and 45.0 per cent for silver.
• Average payable values used were 85 per cent for zinc, 95 per cent for lead and 95 per cent for silver.
• Dilution (inferred and unclassified material set to zero grade) assumed as a minimum of 1.0 m on each hangingwall and 0.5 m on each footwall.
• Mining recovery factors assumed as a minimum of 60 per cent, ranging to 95 per cent, with a weighted average of 93 per cent.
• Mineral reserves are reported based on mined ore delivered to the plant as mill feed.
• The average exchange rate used was $14.90 (Namibian) equals $1 (U.S.).
• Effective date of mineral reserves is March 31, 2021.
• The qualified person for the mineral reserve estimate is Andrew Hall, MAusIMM (CP), of AMC.
• Totals may not compute exactly due to rounding.
• Mineral reserves are stated on a 100-per-cent ownership basis.

Qualified persons and technical information

The written technical disclosure and data in this news release were approved by Yan Bourassa, PGeo, vice-president of technical services of the company. Mr. Bourassa is a non-independent qualified person within the meaning of Canadian National Instrument 43-101 (Standards of Disclosure for Mineral Projects). Qualified persons contributing to the study, who have also read this release, are as follows:

• Andrew Hall, MAusIMM (CPP), AMC Consultants Pty. Ltd., responsible for mining and mineral reserve estimation;
• Rodney Webster, MAIG, AMC Consultants, responsible for geology and mineral resource estimation;
• Louise Lintvelt, PrEng, DRA Projects Pty. Ltd., a wholly owned subsidiary of DRA Global Ltd., responsible for metallurgical and ore processing aspects;
• Rob Welsh, PrEng, DRA Projects, a wholly owned subsidiary of DRA Global, responsible for ore processing and surface infrastructure aspects;
• Mo Molavi, PEng, AMC Mining Consultants (Canada) Ltd., responsible for underground infrastructure aspects.

The mineral resource and mineral reserve estimates have been reported in accordance with definitions and guidelines set out in the definition standards for mineral resources and mineral reserves adopted by the Canadian Institute of Mining, Metallurgy and Petroleum and as required by National Instrument 43-101. Mineral reserve estimates reflect the company's reasonable expectation that all necessary permits and approvals will be obtained and maintained, and mining dilution and mining recovery have been applied in estimating the mineral reserves.

For information regarding the data verification measures applied to the scientific and technical information contained in this news release, please see the FS dated Aug. 17, 2021, and filed on the company's SEDAR profile.

About Trevali Mining Corp.

Trevali is a global base metal mining company, headquartered in Vancouver, Canada. The bulk of Trevali's revenue is generated from base metal mining at its four operational assets: the 90-per-cent-owned Perkoa mine in Burkina Faso, the 90-per-cent-owned Rosh Pinah mine in Namibia, the wholly owned Caribou mine in northern New Brunswick, Canada, and the wholly owned Santander mine in Peru. In addition, Trevali owns the Halfmile and Stratmat properties and the Restigouche deposit in New Brunswick, Canada, and the past-producing Ruttan mine in Northern Manitoba, Canada. Trevali also owns an effective 44-per-cent interest in the Gergarub project in Namibia, as well as an option to acquire a 100-per-cent interest in the Heath Steele deposit located in New Brunswick, Canada.

The shares of Trevali are listed on the Toronto Stock Exchange (symbol TV), the OTCQX (symbol TREVF), the Lima Stock Exchange (symbol TV) and the Frankfurt Stock Exchange (symbol 4TI).

We seek Safe Harbor.