Trevali Mining 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.

Figure 1: Location map of the Heath Steele and Stratmat claim groups showing location of historic mine production, defined resources and known prospects

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.

Figure 2: Map of the Heath Steele E-Zone showing historic drill hole locations (yellow) and recent drilling, assays pending

Figure 3: Various plan and 3-D section views of the Heath Steele drill hole data and the E-Zone

Figure 4: Cross section through the Heath Steele E-Zone, looking WNW

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.