May 8, 2015, Vancouver, British Columbia—TriMetals Mining Inc. (TSX: TMI and TMI.B, US OTCQX: TMIAF & TMIBF), reports the release of its unaudited condensed interim consolidated financial statements for the three months ended March 31, 2015 and the related management’s discussion and analysis of financial position and results of operations (“MD&A”). In this press release, all amounts are expressed in U.S. dollars, unless otherwise indicated.

During the three months ended March 31, 2015, the Company reported net earnings of $712,016 ($0.01 per share) compared to a net loss of $1,806,805 ($0.01 per share) reported in the first quarter of 2014.

The 2015 first quarter earnings include a non-cash income amount of $1,138,077 (2014 – loss of $1,541,928) in respect of the change in fair value of the Company’s Class B shares.

General and administrative expenses decreased to $547,354 in Q1 2015 from $991,279 in Q1 2014 as the Company has continued to streamline its operations and administration during Q1 2015.

Total exploration spending for Q1 2015 decreased marginally to $451,929 from $486,068 incurred in the first quarter of 2014.

Of the exploration spending incurred in Q1 2015, $361,263 was incurred at Gold Springs which mainly included costs associated with updating the mineral resource estimate and ongoing metallurgical testing to support an updated Preliminary Economic Assessment which is expected to be released during May 2015. At Escalones, the Company incurred costs of $90,666 which mainly included land payments and supervision.

At March 31, 2015 the Company had $3,548,228 in cash and cash equivalents. The Company remains in a strong financial position to meet its working capital requirements for the next 12 months.

Outlook

The priorities of the Company are to (i) continue with the exploration program at Gold Springs and move the project closer to production; (ii) seek an appropriate joint venture partner for the Escalones copper-gold porphyry project in Chile; (iii) continue international arbitration proceedings against Bolivia to recover full compensation based on the fair market value for the Malku Khota project; and (iv) diligently continue managing the Company’s cash resources.

About TriMetals Mining Inc.

TriMetals Mining Inc. is a growth focused mineral exploration company creating value through the exploration and development of the near surface, Gold Springs gold-silver project in mining friendly Nevada and Utah in the U.S.A.; the advancement of the large scale Escalones copper-gold project in Chile; and realization of value from the expropriated Malku Khota project in Bolivia through an arbitration process.

The Company’s approach to business combines the team’s track record of discovery and advancement of large projects, key operational and process expertise, and a focus on community relations and sustainable development. Management has extensive experience in the global exploration and mining industry.

The Company’s common shares and Class B shares are listed on the Toronto Stock Exchange under the symbols “TMI” and “TMI.B” and the common shares and Class B shares also trade on the OTCQX market under the symbol “TMIAF” and “TMIBF”. Additional information related to TriMetals Mining Inc. is available at www.trimetalsmining.com and on SEDAR at www.sedar.com.

Forward-looking Statements

Certain statements contained herein constitute “forward-looking statements”. Forward-looking statements look into the future and provide an opinion as to the effect of certain events and trends on the business. Forward-looking statements may include words such as “expected”, “seek”, “continue”, and similar expressions. Information concerning the interpretation of drill results may also be considered forward-looking statements as such information constitutes a prediction of what mineralization might be found to be present if and when a mining project is actually developed. These forward- looking statements are based on current expectations and entail various risks and uncertainties. Actual results may materially differ from expectations, if known and unknown risks or uncertainties affect our business, or if our estimates or assumptions prove inaccurate. Factors that could cause results or events to differ materially from current expectations expressed or implied by the forward-looking statements, include, but are not limited to, uncertainties associated with the arbitration proceeding against Bolivia, including the advancement of the international arbitration process in a customary manner and in accordance with Procedural Order No. 1 (as amended in April 2015), the outcome of the international arbitration process including the timing and the quantum of damages to be obtained, management’s expectation with regard to the final amount of costs, fees and other expenses and commitments payable in connection with the arbitration, and any inability or delay in the collection of the value of any award or settlement; and risks of the mineral exploration industry which may affect the advancement of the Escalones or Gold Springs projects, including possible variations in mineral resources or grade, metal prices, availability of sufficient financing to fund further required work in a timely manner and on acceptable terms, timely receipt of required permits, availability of equipment and qualified personnel, failure of equipment or processes to operate as anticipated, road access to the property, changes in project parameters as plans continue to be refined; and other risks more fully described in the Company’s Annual Information Form filed and publicly available on SEDAR at www.sedar.com. The assumptions made in developing the forward-looking statements include: the ability of the Company to realize value from its investments in Bolivia; the arbitration proceeding in a customary manner and in accordance with Procedural Order No. 1 (as amended in April 2015) and the third party funder honoring its contractual commitments, the accuracy of current resource estimates and the interpretation of drill, metallurgical testing and other exploration results; the timely receipt of required permits for Escalones and Gold Springs projects; the continuing support for mining by local governments in Nevada, Utah and Chile, the availability of equipment and qualified personnel to advance the Escalones and Gold Springs projects; and the execution of the Company’s existing plans and further exploration and development programs for Escalones and Gold Springs Projects, which may change due to changes in the views of the Company or if new information arises which makes it prudent to change such plans or programs.

Readers are cautioned not to place undue reliance on the forward-looking statements contained in this news release. Except as required by law, the Company assumes no obligation to update or revise any forward-looking statement, whether as a result of new information, future events or any other reason. Unless otherwise indicated, forward-looking statements in this news release describe the Company’s expectations as of May 8, 2015.

TriMetals Mining Inc. Contact: