US OTCQX Symbol: TMIAF TriMetals Mining Reports Increased M&I Grade to 0.55 g/t Gold (0.71 g/t AuEq) and 22% Increase in M&I Gold Oz in Updated Pit- Constrained Resource

NEWS RELEASE: 17-05

TSX Symbol: TMI US OTCQX Symbol: TMIAF

TriMetals Mining Reports Increased M&I Grade to 0.55 g/t Gold (0.71 g/t AuEq) and 22% Increase in M&I Gold Oz in Updated Pit- Constrained Resource March 29, 2017, Vancouver, British Columbia—TriMetals Mining Inc. (TSX: TMI, US OTCQX: TMIAF), (the “Company”) is pleased to announce the completion of an updated pit-constrained resource estimate for the Jumbo Trend (including Jumbo North and Jumbo South (Etna) Resource blocks), the Grey Eagle Zone and the Thor Zone at the Gold Springs goldsilver project that straddles the Nevada-Utah border (the “2017 Resource”) with an effective date of March 29, 2017. The Company has now developed resources on all four of the ZTEM geophysical target areas on which it has done detailed drilling. This updated resource includes the drill information from the 2015 and 2016 drill programs and uses capped assay data, a more conservative 0.25 g/t gold cutoff and is pit-constrained.

Importantly the average reported M&I gold grade in the “2017” pit-constrained resource is now 0.55 g/t compared to 0.45 g/t in the “2015” resource and M&I gold oz have increased by 22% to 527,687 oz compared to the “2015” resource even though the “2017” resource is constrained by a higher cutoff grade.

Ralph Fitch, President and CEO of TriMetals Mining Inc., stated “Further drilling has again increased the size and quality of the resource. As the exploration matures we are further constraining our resource model and have increased the cut-off grade to a more conservative 0.25 g/t gold. One of the benefits of this, is the increased reported grade at over 0.5 g/t gold, very much in line with other deposits in Nevada/Utah. We believe this resource makes an excellent starting point for our planned more substantial drill program this year. Importantly we have now developed resources on all four of the ZTEM geophysical target areas on which we have done detailed drilling. Within the Jumbo Trend we have established resources, with openended mineralization, at the northern and southern end of the trend and will be working to infill the 1.5-kilometer zone between these resources during the 2017 drill program. Notably the recent drilling at Jumbo South (Etna) has yielded higher grades and thicknesses of mineralization, allowing us to add more ounces of gold at a higher grade per drill hole in this southern portion of the Jumbo Trend.”

Link to location map showing the four resource blocks: http://www.trimetalsmining.com/wpcontent/uploads/2017/03/GSResourceAreasMar2017.pdf The updated pit-constrained resource using a 0.25 g/t gold cutoff consists of:

Gold Equivalent (AuEq) uses a gold/silver ratio 61.9 and have not been adjusted for metallurgical recoveries. The Inferred resource is in addition to the measured and indicated resource. Numbers have been rounded, which may lead to some numbers not adding up exactly.

The majority of the resource is located in the Jumbo Trend which consists of the resource blocks Jumbo North and Jumbo South (Etna):

Gold Equivalent (AuEq) uses a gold/silver ratio 61.9 and have not been adjusted for metallurgical recoveries. The Inferred resource is in addition to the measured and indicated resource. Numbers have been rounded, which may lead to some numbers not adding up exactly.

The remaining resource lies on the Nevada side of the project and consists of two separate areas, the Thor Zone in the middle of the property and the Grey Eagle towards the NW corner of the property:

Gold Equivalent (AuEq) uses a gold/silver ratio 61.9 and have not been adjusted for metallurgical recoveries. The Inferred resource is in addition to the measured and indicated resource. Numbers have been rounded, which may lead to some numbers not adding up exactly.

This pit-constrained model uses a 0.25 g/t gold cut-off grade compared to 0.2 g/t gold cutoff grade used in the 2015 resource.

An additional 97,000 oz of gold (M&I) and 85,000 oz of gold (Inferred) were estimated outside the pit-constrained model. It is expected that the majority of these ounces will become part of the resource with further drilling because the resource areas are open to expansion down-dip and along strike.

To compare the 2015 Geologic Resource to the present geologic resource on a similar basis we need to look at the 2017 Geologic Resource using a 0.2 g/t gold cutoff-grade and look at the 2015 resource using a gold/silver ratio, for gold equivalent calculation, of 61.9.

The accompanying table demonstrates that on this basis the M&I geologic resources have increased quite substantially, by 327 thousand AuEq oz of a similar grade.

Gold Springs Resource Estimate – IDP* Geologic Resource by Category 0.20 grams/tonne cutoff Category Gold Silver Gold Eq (ratio 61.9) g/t Oz (000) g/t Oz (000) g/t Oz (000) 2017 Geologic Resource

Measured + Indicated 0.46 704 8.44 12,831 0.60 911 Inferred 0.41 184 5.70 2,579 0.50 225

2015 Geologic Resource

Measured + Indicated 0.45 434 9.62 9,296 0.60 584 Inferred 0.34 225 6.87 4,613 0.45 300

Difference ( 2017 resource minus 2015 resource)

Measured + Indicated 0.01 270 (1.18) 3,535 (0.00) 327 Inferred 0.07 (41) (1.17) (2,034) 0.05 (74)

*Inverse distance to a power (IDP)

For comparison purposes only, a cut-off grade of 0.20 g/t Au and a gold/silver ratio, for gold equivalent calculation, of 61.9 is used in this table for both the 2015 and 2017 Resources. Numbers have been rounded, which may lead to some numbers not adding up exactly.

The following tables show the details of the 2017 Updated Resource:

For comparative purposes the Resource is also shown below using the same 0.2 g/t gold cut-off as was used in the 2015 PEA.

Global Resource Engineering (GRE) estimated the mineral resources for each of the four mineral deposits within Gold Springs, the Jumbo Trend including Jumbo North and Jumbo South (Etna), Grey Eagle and Thor, by constructing a geologic model representing the mineralized zones within each deposit including statistically and geostatistically analyzing the drill hole data. This information was used to define the parameters used to estimate gold and silver grades into the 3-dimensional block model. Three types of algorithms were used to estimate grade for both gold and silver within each block model: Geologic solid models of the mineralized zones in each deposit were created in Leapfrog and the grade for those solids was estimated using inverse distance to the 2.5 power (ID2.5) for Jumbo N, Jumbo S (Etna), and Thor, and inverse distance cubed (ID3) for Grey Eagle in 2015, ordinary kriging (OK), and nearest neighbor (NN) algorithms using Techbase and Micromodel. The results from each method were very similar, validating the estimate. The inverse distance to a power (IDP) estimate is most comparable to prior estimates, is the preferred estimate, and is reported here.

The data used for the estimation includes the following:

The drill holes in the Jumbo North area total 17,229.91 metres, and the channels total 161.87 metres. There are 9,813 gold and silver assay data values in the Jumbo North database.

The drill holes in the Jumbo South (Etna) area total 2,917.16 metres, and the channels total 329.19 metres. There are 2,071 gold and silver assay data values in the Etna database.

The drill holes in the Thor area total 2,890.03 metres. There are 1,233 gold and silver assay data values in the Thor database.

The data includes 94 exploration holes and trenches in the Grey Eagle deposit totaling 12,401 metres. Within the Grey Eagle, deposit, there are 6,906 gold sample results.

The geologic solid model utilized a block model with 5 metre by 5 metre by 5 metre blocks (xyz) and the geological interpretation of the mineralized envelope to isolate the mineralized domain from non-mineralized rock and to control estimation of gold and silver near known faults. An inverse distance 2.5 algorithm was used with a minimum of 2 drill holes.

GRE classified the Mineral Resource as Measured with an average distance of less than 25 meters from drill holes, Indicated with an average distance of 25 to 50 metres from holes, and Inferred with an average distance between 50 metres and 100 meters.

GRE is not aware of any legal, political, environmental, or other risks that could materially affect the potential development of the mineral resources at Gold Springs.

The Technical Report, including the 2017 Resource, is near completion and will be filed on SEDAR on March 31, 2017.

Gold Equivalence: AuEq* was calculated using a gold/silver ratio of 61.9 and has not been adjusted for metallurgical recoveries.

Qualified Person

The Mineral Resource has been prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), CIM Standards on Mineral Resources and Reserves, Definitions and Guidelines prepared by the CIM Standing Committee on Reserve Definitions and adopted by the CIM by Ms. Terre Lane, Principal Mining Engineer for Global Resource Engineering, Mr. Kevin Gunesch, Principal Mining Engineer for Global Resource Engineering and Mr. Kurt Katsura, Consulting Geologist, all Qualified Professionals as defined in National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101), and are “independent” of the Company as defined in NI 43-101, and all have reviewed and approved the technical information regarding the resource estimate in this release. TMI Assays were performed in Sparks, Nevada by Bureau Veritas Mineral Laboratories, an ISO 9001:2000 Certified laboratory.

Cautionary Statement on Mineral Resources

This news release uses the term ‘measured resources’, ‘indicated resources’ and 'inferred resources' which are terms recognized and required by Canadian regulations (under National Instrument 43-101 Standards of Disclosure for Mineral Projects), however, such terms are not defined terms under SEC Industry Guide 7 and are not permitted to be used in reports and registration statements filed with the United States Securities and Exchange Commission. Investors are cautioned not to assume that any part or all of the mineral deposits in these categories will be upgraded or converted into ‘reserves’ as defined under NI 43-101. Mineral resources that are not mineral reserves, do not have demonstrated economic viability. In addition, 'inferred resources' have a great amount of uncertainty as to their existence, and economic and legal feasibility. It cannot be assumed that an inferred resource will be upgraded to a higher category. Under Canadian rules, estimates of inferred resources may not form the basis of feasibility or pre-feasibility studies, or economic studies except for preliminary economic assessment as defined under NI 43-101. Investors are cautioned not to assume that part or all of an inferred resource exists, or is economically or legally mineable.

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 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”. Note that the Class B shares have no interest in the properties or assets of the Company. The Class B shares are only entitled collectively to 85% of the net cash, if any, (after deducting all costs, taxes and expenses and the third-party funder's portion thereof) received by TMI from award or settlement in relation to the Company’s subsidiary South American Silver Limited’s arbitration proceeding against Bolivia for the expropriation of the Malku Khota project in 2012. 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 “further”, “target”, “expansion”, “believe”, “planned”, “open”, “will”, “become”, “expected” and similar expressions. Information concerning mineral resource estimates and the interpretation of drill, metallurgical testing and other exploration 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, possible variations in mineral resources, grade, metal prices; any delay in the completion by the independent qualified persons of the NI 43-101 compliant technical report supporting the new resource estimate for Gold Springs; availability of sufficient financing to fund planned or further required work in a timely manner and on acceptable terms; changes in project parameters as plans continue to be refined; failure of equipment or processes to operate as anticipated; regulatory, environmental and other risks of the mining industry more fully described in the Company’s Annual Information Form and continuous disclosure documents which are available on SEDAR at www.sedar.com. The assumptions made in developing the forward-looking statements include: the accuracy of current resource estimates and the interpretation of drill, metallurgical testing and other exploration results; the timely receipt of required permits for the Gold Springs project; the continuing support for mining by local governments in Nevada and Utah; the availability of equipment and qualified personnel to advance the Gold Springs project; execution of the Company’s existing plans and further exploration and development programs for Gold Springs, 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; and the timely completion by the independent qualified persons of a NI 43-101 compliant technical report supporting the resource estimate by March 31, 2017.

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 March 29, 2017.

TriMetals Mining Inc. Contact:

Ralph Fitch Matias Herrero President & CEO Chief Financial Officer 303.584.0606 303.584.0606 [email protected] [email protected]