Trevali Commences Mill Commissioning at Caribou Zinc Mine

VANCOUVER, BRITISH COLUMBIA--(Marketwired - May 19, 2015) - Trevali Mining Corporation ("Trevali" or the "Company") (TSX:TV) (LMA:TV) (OTCQX:TREVF) (FRANKFURT:4TI) announces that mill commissioning at its 3,000-tonne-per-day Caribou Zinc Mine in the Bathurst Mining Camp of northern New Brunswick has commenced following the recent successful initiation of underground mining.

All key mill circuits: Crushing - Grinding - Flotation - Concentrate Filters - Metallurgical & Geochemical Laboratories and Concentrate Handling have been either fully replaced, refurbished or repaired where necessary and are available for commissioning by Trevali's Plant team.

Consultant DRA Americas Inc.'s metallurgical processing specialists are fully mobilized on site and focusing on operator training and troubleshooting, in addition to updating operational and preventative maintenance programs to de-risk commissioning and mill ramp-up periods to commercial operation. XPS Consulting & Testwork Services have also been retained to provide metallurgical support in addition to Glencore Technology for the IsaMills.

CARIBOU COMMISSIONING STRATEGY

Based on lessons learned during our successful 2013 Santander Mill commissioning, the Company has adopted a measured or phased commissioning plan for the more complex Caribou mineralization, including:

• In order to ensure sufficient feed is available for commissioning, mining has produced an approximately 75,000-tonne surface mineralized mill-feed stockpile from underground ("UG") development and production stopes with an additional 28,000 tonnes of mill-feed drilled and readily available for blast and mucking through the new ramp system (Figure 1). UG development and production has been going exceptionally well, additional details are discussed below.

• Initial commissioning will commence with low-grade material as the operators bring the grinding and flotation circuits up to specification. Positive-loop iterative optimization will occur during night-shift based on results obtained during the day with input from DRA and the various metallurgical support teams. Flotation and subsequent concentrate production will focus on the established Zn and Pb (Ag) circuits (Figure 2), with Cu (Au) circuit commissioning scheduled to commence later this year.

• Once sufficient operational data is obtained, tentatively during July-August, Trevali will mobilize its senior metallurgical consultant to site to provide additional technical and metallurgical support capacity. Glencore will also make available several of their Australian IsaMill specialists during this period if required.

• Concentrate trucking has been tendered and awarded with site specific training and orientation in progress. The Company will build a stockpile of concentrate on site prior to shipping and sale to Glencore at their adjacent Belledune smelting complex tentatively anticipated in late-Q2 to early-Q3.

To view Figure 1: Caribou Mine mineralized mill feed radial stockpile of approximately 75,000 tonnes, please visit the following link: http://media3.marketwire.com/docs/1007850_fig1.pdf