Eastmain and Partners Announce Fall 2018 Exploration Program at Éléonore South Joint Venture

TORONTO, Sept. 11, 2018 - Eastmain Resources Inc. (“Eastmain” or the “Company”- TSX:ER, OTCQX:EANRF) announces the Fall 2018 Exploration Program at the Éléonore South Joint Venture Property (“ESJV”) located in James Bay, Quebec (see Figure 1).

Fall 2018 Exploration Program

Eastmain is the manager of the ESJV and has presented its partners with a $2.5 million budget for surface exploration and diamond drilling for the balance of 2018, focusing on two significant gold targets:

Contact Trend

• 1,250 m of mechanized trenching to explore the contact between the Cheechoo tonalite and overlying metasedimentary rocks (see Figure 2) from the drill identified Contact Trend mineralization in the east to the JT Prospect in the west.

• Up to 5,800 m of diamond drilling will also be completed focusing on:

a) continued evaluation of an extensive gold bearing system hosted in the Cheechoo tonalite intrusion

b) expanding the identified Contact Trend mineralized envelope westward along the southeastern boundary of the Cheechoo tonalite and establishing greater definition of higher grade gold mineralization, and

c) following up on previously identified Contact Trend gold mineralization in the tonalite intrusion below the JT Prospect, located along the western edge of the intrusive.

Moni Trend

• 750 m of mechanized trenching to explore along trend for the southwestern extension of high-grade gold mineralization in recently discovered pegmatitic quartz-feldspar veins (see press release dated October 17, 2017). Results from the trenching program will be used to focus new drilling along this zone.

• Using trench information and recent drilling results to guide up to 1,200 m of diamond drilling testing extensions of Moni Prospect mineralization and new targets along the Moni Trend.

Claude Lemasson, President & CEO, stated: “As part of launching the Fall 2018 Exploration Program, several members of Eastmain’s board of directors and senior management visited site last week. After two years of working on the Moni and Contact Trends and announcing an important discovery last fall, we are looking forward to advancing this project through further trenching and drilling to better define this gold system.”

Exploration Potential

The joint venture began exploring the Cheechoo tonalite intrusion in 2016. Seventy-six diamond drill holes (15,134 m) completed on the property have identified a large gold-bearing system within the northeastern margin of a tonalite intrusion located in the eastern section of the ESJV property. Drilling has identified gold mineralization in a 600 m to 700 m wide zone extending over two kilometres along a north-easterly trend. The mineralization extends towards the Sirios Cheechoo discovery to the northeast and is open to the west and southwest. The gold-bearing system drilled during this period is wholly contained within the Cheechoo tonalite intrusion and comprised of two main expressions:

• The Contact Trend: A mineralized and altered envelope of variable thickness in tonalite which ranges from several tens of metres to over 100 m in core length with continuous intervals of anomalous gold values. Within these intervals are sections ranging to several tens of metres returning above 0.5 g/t Au. Alteration is characterized by the appearance of one or several networks of quartz veins and veinlets, sodic alteration, the presence of frequent visible gold grains and a notable but very low sulphide concentration (<0.5%) including arsenopyrite; and

• The Moni Trend: Several high-grade gold mineralized zones characterized by a) clusters of quartz-albite-biotite stockworks accompanied by arsenopyrite, pyrrhotite, pyrite, scheelite and visible gold, and b) pegmatitic veins of coarse quartz and feldspar or veins of coarse grained quartz with lesser amounts of interstitial feldspar having well distributed visible gold and very low sulphide content.

The late (2.61 billion-year-old) Cheechoo tonalite is interpreted to be a mushroom shaped intrusion (lopolith) with a 450 m to 500 m thick, roughly tabular top having a shallow to moderate dip to the south along its southern contact and a moderate dip to the west along its western contact (JT Prospect area). The current interpretation suggests the intrusion has not been overturned. The Contact Trend is interpreted to represent a decompression stockwork zone close to the top of the intrusion. This mineralized zone may extend down dip along the top of the intrusion, parallel to, and below, the contact with the overlying metasedimentary country rocks. The relationship of the high-grade Moni-type veins to Contact Trend mineralization is not fully established yet. They are explored separately but certain elements of the alteration and mineralization such as distribution of visible gold and generally low sulphide contents suggest common genesis. Further discussion of the exploration model adopted for the Cheechoo tonalite mineralization is provided in a press release dated July 18, 2018.

The JT Prospect is located 2.5 km to 3 km to the west of the Contact and Moni Trends mineralization identified since 2016. This is a gold-bearing zone explored by drilling in 2008-2009 while targeting sedimentary sequences believed to have a similar geology to those within the stratigraphy hosting the Éléonore gold mine, located 12 km to the northwest. Gold was identified in the metasedimentary rocks located above the tonalite-metasedimentary contact at the time. Tonalite was generally used to define the base of drilling, however analytical results from some historic drill holes indicate that the Cheechoo tonalite is also mineralized in this area, including hole ES08-12 which returned 2.15 g/t Au over 14 m in the intrusive (see Figure 3).

Gold intercepts in tonalite at the JT Prospect near the intrusive-metasedimentary contact may extend the highly prospective Contact Trend to a semi-circular ring shape of approximately 5.5 km in length. The Joint Venture will drill test the Cheechoo tonalite below the JT Prospect in the coming months.

To view FIGURES 1 - 3, please click on the following link:
http://www.eastmain.com/_resources/images/Figures1-3.pdf

About the Eleonore South Joint Venture Property

The Éléonore South Property is being explored as a three-way joint venture between Eastmain Resources Inc. (36.7%), Azimut Exploration Inc. (TSX.V:AZM) (26.6%), and Goldcorp Inc. (TSX:G; NYSE:GG) (36.7%). Eastmain is the operator of the current program under the supervision of William McGuinty, P. Geo., Eastmain’s VP Exploration and a qualified person under National Instrument 43-101. This press release and supporting technical information was reviewed by William McGuinty.

About Eastmain Resources Inc. (TSX:ER, OTCQX:EANRF)

Eastmain is a Canadian exploration company advancing three high-grade gold assets in the emerging James Bay gold camp in Québec. The Company holds a 100% interest in the Eau Claire Project, for which it recently issued a Preliminary Economic Assessment (“PEA”), and the Eastmain Mine Project where the Company prepared a NI 43-101 Mineral Resource Estimate in 2018. Eastmain is also the manager of the Éléonore South Joint Venture which hosts a new high-grade gold discovery found in late 2017 and is located immediately south of Goldcorp Inc.'s Éléonore Mine. In addition, the Company has a pipeline of exploration projects in this favourable mining jurisdiction with nearby infrastructure.

For more information:

Claude Lemasson, President and CEO
+1 647-347-3765
lemasson@eastmain.com

Laurenn Russell, Investor Relations Consultant
+1 647-347-3735
lrussell@eastmain.com

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 and 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 effect 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 preparations 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.