Trevali intersects wide interval of massive sulphide mineralization at Heath Steele project in New Brunswick

VANCOUVER, BRITISH COLUMBIA--(Marketwired - May 5, 2017) - Trevali Mining Corporation ("Trevali" or the "Company") (TSX:TV)(LMA:TV)(OTCQX:TREVF)(FRANKFURT:4TI) announces initial results from its drill program on the Heath Steele project located adjacent to the Company's Stratmat zinc deposit in the Bathurst Mining Camp of northeastern New Brunswick. The drill program is testing the E-Zone at Heath Steele, an advanced-stage, near-surface target with historic, non-National Instrument 43-101-compliant resources. Trevali has completed an initial data validation drill program testing this target, and additional results will be reported as they become available.

Heath Steele

As part of the recently announced definitive agreement to acquire a portfolio of zinc assets from Glencore PLC, Trevali has commenced exploration on the Heath Steele claim group (Figure 1). Mining operations at Heath Steele were carried out by a variety of companies (including Noranda) discontinuously between 1957 and 1999. Over Heath Steele's long mine life, zinc, lead, copper, silver and gold were extracted from several zones on the property (see Table 1 and Figure 1). Multiple exploration campaigns over the Heath Steele property identified and tested a number of targets. One of the more advanced targets from this work is the E-Zone.

To view Figure 1: Location map of the Heath Steele and Stratmat claim groups showing location of historic mine production, defined resources and known prospects, visit the following link:http://media3.marketwire.com/docs/1093524-F1.pdf

E-Zone

The E-Zone has sulphide mineralization exposed at surface and has been previously tested and defined by more than 150 historic drill holes (Figure 2). Based on the available historic drill hole data, E-Zone appears to be comprised of two stacked sulphide lenses each approximately 150 metres in length and with thicknesses ranging from 5-30 metres (Figures 3 and 4). The lenses merge towards surface and have a vertical continuity of approximately 200 metres. Highlights from some of the historic drilling at the E-Zone are presented in Table 2.

2017 Drill Program

In March 2017, Trevali commenced an initial 7-hole, 1,200-metre drill program to validate historic data and to collect material for metallurgical test work (Figure 4). The first drill hole, HS17-001 successfully intersected 56.2 metres of sulphide mineralization grading at 3.84% Zn, 1.51% Pb, 2.15% Cu, 64.3 g/t Ag and 1.01 g/t Au, within which significantly higher grade intervals occur (see Table 3). Interestingly elevated cobalt values were also encountered within the mineralization. Several samples had Co values of 0.4% (4,000 ppm, the upper detection limit) and the average Co grade over the entire 56.2-metre interval was 0.15% (1,450 ppm). Additional drill results will be released as they become available. Metallurgical testing will commence upon completion of program and receipt of all assay results.

Additional exploration work is planned for the Heath Steele claim group in 2017 including a detailed review of the available historic data. Results from this data review will prioritize exploration efforts with the goal of quickly adding mineable resources to Trevali's growing operations in the Bathurst Mining Camp of New Brunswick.

To view Figure 2: Map of the Heath Steele E-Zone showing historic drill hole locations (yellow) and recent drilling, assays pending, visit the following link: http://media3.marketwire.com/docs/1093524-F2.pdf

To view Figure 3: Various plan and 3-D section views of the Heath Steele drill hole data and the E-Zone, visit the following link: http://media3.marketwire.com/docs/1093524-F3.pdf

To view Figure 4: Cross section through the Heath Steele E-Zone, looking WNW, visit the following link: http://media3.marketwire.com/docs/1093524-F4.pdf

Q1-2017 Financial Results and Conference Call

Trevali will release financial results for its first quarter period ending March 31, 2017, on May 15, 2017 after the close of the trading day in Toronto. The Company will host a conference call and audio webcast at 10:30 a.m. Eastern Time on Tuesday, May 16th, 2017, to review the financial results. Conference call dial-in details and audio webcast link will be provided in the financial results news release.

Qualified Person and Quality Control/Quality Assurance

EurGeol Dr. Mark D. Cruise, Trevali's President and CEO and Daniel Marinov, P.Geo, Trevali's VP Exploration, are qualified persons as defined by NI 43-101, have supervised the preparation of the scientific and technical information that forms the basis for this news release. Mr. Marinov is responsible for all aspects of the work, including the quality control/quality assurance programs. Dr. Cruise is not independent of the Company, as he is an officer, director and shareholder. Mr. Marinov is not independent of the Company as he is an officer and shareholder. On-site personnel at the project rigorously collect and track samples which are then security sealed and shipped to Bureau Veritas Laboratories preparation facility in Timmins, Ontario, then the pulp samples are shipped to Vancouver, BC for assay. Zinc, lead, copper gold and silver, assays were obtained by four acid Aqua-Regia dissolution followed by Inductively coupled plasma optical emission spectrometry (ICP-OES) measurements. Values of Zinc, lead and copper over 10% are assayed by volumetric method. Analytical accuracy and precision are monitored by the analysis of reagent blanks, reference material and replicate samples. Quality control is further assured by the use of international and in-house standards. Blind certified reference material is inserted at regular intervals into the sample sequence by Trevali personnel in order to independently assess analytical accuracy. Bureau Veritas' quality system complies with the requirements for the International Standards ISO 9001:2000 and ISO 17025: 1999. Finally, representative blind duplicate samples are routinely forwarded to an ISO compliant third party laboratory for external quality control.

ABOUT TREVALI MINING CORPORATION

Trevali is a zinc-focused, base metals mining company with two commercially producing operations.

The Company is actively producing zinc and lead-silver concentrates from its 2,000-tonne-per-day Santander mine in Peru and its 3,000-tonne-per-day Caribou mine in the Bathurst Mining Camp of northern New Brunswick. Trevali also owns the Halfmile and Stratmat base metal deposits, located in New Brunswick, that are currently undergoing a Preliminary Economic Assessment reviewing their potential development. Additionally, the Company has entered into a definitive agreement with Glencore PLC to acquire a portfolio of zinc assets from Glencore, including an 80% interest in the Rosh Pinah mine in Namibia, a 90% interest in the Perkoa mine in Burkina Faso, an effective 39% interest in the Gergarub project in Namibia, an option to acquire 100% interest in the Heath Steele property in Canada and certain related exploration properties and assets.

The common shares of Trevali are listed on the TSX (symbol TV), the OTCQX (symbol TREVF), the Lima Stock Exchange (symbol TV), and the Frankfurt Exchange (symbol 4TI). For further details on Trevali, readers are referred to the Company's website (www.trevali.com) and to Canadian regulatory filings on SEDAR at www.sedar.com.

On Behalf of the Board of Directors of

TREVALI MINING CORPORATION

Mark D. Cruise, President

This news release contains "forward-looking statements" within the meaning of the United States private securities litigation reform act of 1995 and "forward-looking information" within the meaning of applicable Canadian securities legislation. Statements containing forward-looking information express, as at the date of this news release, the Company's plans, estimates, forecasts, projections, expectations, or beliefs as to future events or results and the Company does not intend, and does not assume any obligation to, update such statements containing the forward-looking information. Such forward-looking statements and information include, but are not limited to statements as to: the expected benefits of the proposed Transaction, the closing the Transaction,, including the anticipated timing thereof, the satisfaction of all conditions to closing the Transaction and the Offering including, without limitation, obtaining all necessary consents and approvals, the completion of the debt financing, the Company's plan to prepare a new PEA for its Halfmile and Stratmat properties, the accuracy of estimated mineral resources, anticipated results of future exploration, and forecast future metal prices, expectations that environmental, permitting, legal, title, taxation, socio-economic, political, marketing or other issues will not materially affect estimates of mineral resources. These statements reflect the Company's current views with respect to future events and are necessarily based upon a number of assumptions and estimates that, while considered reasonable by the Company, are inherently subject to significant business, economic, competitive, political and social uncertainties and contingencies.

These statements reflect the Company's current views with respect to future events and are necessarily based upon a number of assumptions and estimates that, while considered reasonable by the company, are inherently subject to significant business, economic, competitive, political and social uncertainties and contingencies. Many factors, both known and unknown, could cause actual results, performance or achievements to be materially different from the results, performance or achievements that are or may be expressed or implied by such forward-looking statements contained in this news release and the Company has made assumptions and estimates based on or related to many of these factors. Such factors include, without limitation: fluctuations in spot and forward markets for silver, zinc, base metals and certain other commodities (such as natural gas, fuel oil and electricity); fluctuations in currency markets (such as the Canadian dollar and Peruvian sol versus the U.S. dollar); risks related to the technological and operational nature of the Company's business; changes in national and local government, legislation, taxation, controls or regulations and political or economic developments in Canada, the United States, Peru or other countries where the Company may carry on business in the future; risks and hazards associated with the business of mineral exploration, development and mining (including environmental hazards, industrial accidents, unusual or unexpected geological or structural formations, pressures, cave-ins and flooding); risks relating to the credit worthiness or financial condition of suppliers, refiners and other parties with whom the Company does business; inadequate insurance, or inability to obtain insurance, to cover these risks and hazards; employee relations; relationships with and claims by local communities and indigenous populations; availability and increasing costs associated with mining inputs and labour; the speculative nature of mineral exploration and development, including the risks of obtaining necessary licenses and permits and the presence of laws and regulations that may impose restrictions on mining; diminishing quantities or grades of mineral resources as properties are mined; global financial conditions; business opportunities that may be presented to, or pursued by, the Company; the Company's ability to complete and successfully integrate acquisitions and to mitigate other business combination risks; challenges to, or difficulty in maintaining, the Company's title to properties and continued ownership thereof; the actual results of current exploration activities, conclusions of economic evaluations, and changes in project parameters to deal with unanticipated economic or other factors; increased competition in the mining industry for properties, equipment, qualified personnel, and their costs.

Investors are cautioned against attributing undue certainty or reliance on forward-looking statements. Although the Company has attempted to identify important factors that could cause actual results to differ materially, there may be other factors that cause results not to be as anticipated, estimated, described or intended. The Company does not intend, and does not assume any obligation, to update these forward-looking statements or information to reflect changes in assumptions or changes in circumstances or any other events affecting such statements or information, other than as required by applicable law.

Trevali's production plan at the Caribou Mine is based only on measured, indicated and inferred mineral resources, and not mineral reserves, and does not have demonstrated economic viability. Trevali's production plan at the Santander Mine is based only on measured, indicated and inferred mineral resources, and not mineral reserves, and does not have demonstrated economic viability. Inferred mineral resources are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves, and there is therefore no certainty that the conclusions of the production plans and Preliminary Economic Assessment (PEA) will be realized. Additionally, where Trevali discusses exploration/expansion potential, any potential quantity and grade is conceptual in nature and there has been insufficient exploration to define a mineral resource and it is uncertain if further exploration will result in the target being delineated as a mineral resource.

We advise US investors that while the terms "measured resources", "indicated resources" and "inferred resources" are recognized and required by Canadian regulations, the US Securities and Exchange Commission does not recognize these terms. US investors are cautioned not to assume that any part or all of the material in these categories will ever be converted into reserves.

This news release does not constitute an offer to sell or a solicitation of an offer to buy any of the securities in the United States. The securities described herein have not been and will not be registered under the United States Securities Act of 1933, as amended, or the securities laws of any state and may not be offered or sold within the United States, absent such registration or an applicable exemption from such registration requirements.

The TSX has not approved or disapproved of the contents of this news release.