Eastmain Completes Eau Claire Definition Drilling Program; Mineral Resource Update Underway

TORONTO, ONTARIO--(Marketwired - July 13, 2017) - Eastmain Resources Inc. ("Eastmain" or the "Company") (TSX:ER)(OTCQX:EANRF) is pleased to announce the completion of the mineral resource definition drill program, including assays from the final 9 holes (3,212 m), from the Eau Claire gold deposit, located in James Bay, Qu?(C)bec. The completed drill program comprised 161 holes (52,420 m) within the deposit's resource envelope to a depth of approximately 400 m (see FIGURES 1-5). The Company's 100%-owned Clearwater Project hosts the Eau Claire gold deposit.

Drill Program Highlights:

• New understanding of the High-Grade Schist (HGS) Veins' importance to underground mining potential
• Improved understanding of vein development, supporting further exploration of deep targets
• Mineral resource work on track with SGS Geostat (mineral resource update expected Q3 2017)
• Additional +10,000 m drilling program in progress

Final Assay Highlights Include:

• Near surface (maximum vertical depth of 100 m) results:
  • ER17-754 - 4.82 g/t Au over 3.9 m, incl. 19.9 g/t Au over 0.8 m
  • ER17-719 - 13.9 g/t Au over 1.0 m
• Shallow underground (vertical depth 100 - 400 m) results:
  • ER17-769 - 4.47 g/t Au over 9.8 m, including 16.9 g/t Au over 2.0 m
  • ER17-769 - 20.0 g/t Au over 1.0 m

Claude Lemasson, Eastmain President and CEO, commented, "This wraps up a successful infill drilling program and concludes a transitional year with a new management team, vision and strategy for the Company. Throughout the drilling program, our team has focused on improving the quality of the deposit's mineral resource base. By expanding the understanding of Eau Claire mineralizing controls and confirming the geological interpretation of the deposit, we now have the foundation in place for an updated mineral resource and maiden preliminary economic assessment. Looking forward at our Clearwater Project, our exploration teams will be dedicated to the growth of the Eau Claire deposit and surrounding targets."

Exploration Objectives Successful

Objective 1: Tighter Drill Spacing to Increase Mineral Resource Confidence

Infill drilling at the Eau Claire deposit has focused on better defining two distinct gold bearing vein systems. Drill spacing was also reduced to 25 m x 25 m within the core of the known deposit to improve the data inputs for the upcoming mineral resource estimate and to provide better controls for designing the Preliminary Economic Assessment expected in Q1 2018. The current footprint of the deposit extends 1,400 m long by 500 m wide.

Objective 2: Expanding the Understanding of Mineralizing Controls

The Company's recently completed infill program provided an improved understanding regarding the structurally-controlled Quartz-Tourmaline (QT) and High-Grade Schist (HGS) veins. In particular, the quartz-feldspar porphyry hanging-wall and volcaniclastic foot-wall (FIGURE 2) appear to represent key controls for gold enrichment zones. The controlling hanging-wall and foot-wall continue to depth, and will guide future expansion drilling programs.

Objective 3: Geological Interpretation and Extending Mineralized Envelopes

At the 450W Zone, improved definition of QT veins in certain parts of the deposit form an en-echelon grouping overall, with locally denser vein clusters. Both the overall QT vein array and the clusters appear to 'climb downward' steeply to the east, creating an interpreted steep SE plunge to the vein system. This orientation will be used to guide deep drilling of the deposit while the spacing of the interpreted QT vein clusters will also be tested. HGS vein dimensions were also better defined by the infill program. Potential exists to intersect these structures down-plunge to the east below the deposit, as expansion of the resource envelope.

Drilling confirmed the current geologic understanding of the QT Veins. Infill drilling has identified new vein clusters in certain areas of the deposit (FIGURE 3). Similar to the multiple vein cluster seen in surface exposure at the 450W outcrop, a second cluster set was discovered approximately 400 m southeast, at a 380 m vertical depth at the lower extent of infill drilling (see press release dated, June 1, 2017). A similar cluster is also seen at a depth of approximately 175 m to 200 m depth roughly midway between these two clusters. Within the clusters, which can extend up to 100 m in strike, the QT veins can thicken to 2-3 m in width. Additional analysis will be conducted on how these clusters of denser and higher-grade veins are distributed within the deposit and how they would relate to future development.

Infill drilling improved definition of the HGS veins, which can report high gold grades and are interpreted to cross cut the 450W suite of QT Veins (FIGURE 4). Currently, four veins in the 450W area are classified as HGS veins, with two, HGS-02 and HGS-04, being traced over substantial distances across the deposit. HGS veins are of variable width, ranging up to 13 m, and averaging 3 m in width. In addition to the quartz-tourmaline mineralization common to all gold bearing zones in the Eau Claire deposit, the HGS veins are strongly sheared/foliated and are composed of variable amounts of typical host rock alteration minerals including actinolite, biotite, carbonate and silica. Despite being limited in number, HGS Veins are observed to be, on average, thicker than the QT veins while hosting similar grade gold mineralization.

The HGS-02 vein has an identified strike extent of approximately 350 m and 330 m of dip extent. The HGS-04 vein has a strike extent of 650 m and dip extent of 300 m. Both HGS-02 and HGS-04 remain open along strike and down-dip. Additional work is currently underway to test and extend the known limits of the HGS Veins.

Final Assays from Infill Drilling Program

A total of 4 infill holes reported here tested the 850W Zone and 5 infill holes tested the 450W Zone, rounding out the mineral resource definition program (FIGURE 1). A summary of selected high grade assay results from this drilling are presented in Table 1 below. TABLE 2 represents the complete set of significant results.

TABLE 1: Highlights from Eau Claire Drilling Results

Next Steps at Eau Claire: Additional 10,000+ m Drilling

Three drills continue to work on and around the Eau Claire deposit. A total of at least 10,000 m is expected to be complete by the end of July in advance of the 2H 2017 growth-focused drilling program, which is in the final planning stages.

Priority targets include (FIGURE 5):

1. Inferred mineral resource zones from 400 m to 700 m vertical depth (50 m to 75 m drill spacing) below the measured and indicated mineral resources
2. Continuity of the HGS Veins with several oblique, shear parallel holes; successful intersections will provide greater understanding of the HGS mineralization and help target for future drilling
3. Testing the 'Gap' zone, an area of limited drilling at the point of convergence between the 450W and 850W zones
4. Additional targets from current interpretations which can expand the mineral resource envelope

Mineral Resource Estimate Underway

The Eastmain interpretation and wireframe of the Eau Claire deposit including all information from the latest 161-hole program is complete and delivered to SGS Geostat. Eastmain intends to provide the results of the additional 10,000 m of drilling now underway at Eau Claire to SGS Geostat for inclusion in the new mineral resource. The upcoming resource will outline potential open pit and shallow underground mineral resources and is on track to be delivered in Q3 2017.

The design of the Eastmain Resources' drilling programs, Quality Assurance/Quality Control and interpretation of results is under the control of Eastmain's geological staff, including qualified persons employing a strict QA/QC program consistent with NI 43-101 and industry best practices. The Clearwater project is supervised by Eastmain's Project Geologist, Michel Leblanc P. Geo.

Drill core is logged and split with half-core samples packaged and delivered to ALS Minerals laboratory. Samples are dried and subsequently crushed to 70% passing a 2 mm mesh screen. A 1,000 g subsample is pulverized to a nominal 85% passing 75 micron mesh screen. The remaining crushed sample (reject) and pulverized sample (pulp) are retained for further analysis and quality control. All samples are analysed by Fire Assay with an Atomic Absorption (AA) finish using a 50 g aliquot of pulverized material. Assays exceeding 5 g/t Au are re?EUR?assayed by Fire Assay with a Gravimetric Finish. Eastmain regularly inserts 3rd party reference control samples and blank samples in the sample stream to monitor assay performance and performs duplicate sampling at a second certified laboratory. For 2016, approximately 10% of samples submitted are part of the Company's laboratory sample control protocols.

This press release was compiled and reviewed by William McGuinty, P. Geo., Eastmain's VP Exploration and Qualified Person under National Instrument 43-101.

To view FIGURES 1-5, please click on the following link: www.eastmain.com/_resources/news/Images/ER-170713-Figures1-5.pdf

To view TABLE 2, please click on the following link: www.eastmain.com/_resources/news/Images/ER-170713-DrillTable.pdf

About Eastmain Resources Inc. (TSX:ER)

Eastmain is a Canadian exploration company with 100% interest in the Eau Claire and Eastmain Mine gold deposits, both of which are located within the James Bay District of Quebec. Clearwater, host of the Eau Claire deposit, is the Company's core asset with access to superior infrastructure in a favourable mining jurisdiction. Eastmain also holds a pipeline of exploration projects in this new Canadian mining district, including being a partner in the ??l?(C)onore South Joint Venture.

Forward- Looking Statements - Certain information set forth in this news release may contain forward-looking statements that involve substantial known and unknown risks and uncertainties. Forward-looking statements consist of statements that are not purely historical, including statements regarding beliefs, plans, expectations or timing of future plans, and include, but not limited to, statements with respect to the potential success of the Company's future exploration and development strategies. These forward-looking statements are subject to numerous risks and uncertainties, certain of which are beyond the control of Eastmain, including, but not limited to the impact of general economic conditions, industry conditions, dependence upon regulatory approvals, the availability of financing, timely completion of proposed studies and technical reports, and risks associated with the exploration, development and mining industry generally such as economic factors as they affect exploration, future commodity prices, changes in interest rates, safety and security, political, social or economic developments, environmental risks, insurance risks, capital expenditures, operating or technical difficulties in connection with development activities, personnel relations, the speculative nature of gold exploration and development, including the risks of diminishing quantities of grades of Mineral Resources, contests over property title, and changes in project parameters as plans continue to be refined. Readers are cautioned that the assumptions used in the preparation of such information, although considered reasonable at the time of preparation, may prove to be imprecise and, as such, undue reliance should not be placed on forward-looking statements. The Company assumes no obligation to update such information, except as may be required by law.