Amec Foster Wheeler Environment & Infrastructure 160 Traders Blvd. E., Suite 110 Mississauga, Ontario, L4Z 3K7 Tel: (905) 568-2929 Fax: (905) 568-1686 amecfw.com

December 9, 2016 TC150320 Mr. Bertho Caron Greenstone Gold Mines 365 Bay Street, Suite 500 Toronto, Ontario M5H 2V1 Dear Mr. Caron: Re: Hardrock Project – Revised Tailings Management Facility Alignment The tailings management facility (TMF) layout was updated to provide the required 120 m setback from Kenogamisis Lake respecting the surface rights reservation on crown land. Figure 1 shows the revised layout plan. In relation to the layout presented in the final TMF feasibility report, which is included as Appendix K of the final EIS/EA, the northeast corner of the TMF southeast dam has been relocated by moving it north to satisfy the offset guidelines. Table 1 summarizes the impact on the TMF storage at the end of years 2 and 4 of operations, as well as at the end of the project life, for the same tailings discharge elevation. The storage reductions relative to the original design are not considered to be significant and fall within the range of uncertainty associated with estimating the deposited dry density of the tailings. The estimated dry density is used to infer the deposited volume for a given tonnage.

Table 1: Change in Storage Capacity due to TMF Dam Alignment Modification

Operational Years Deposited Tailings Volume For

the Revised Alignment (Million m3)

% Incremental Reduction in Storage

Capacity

End of year 2 11.6 7 End of year 4 26.0 4 End of mine life 105.6 2.2

Figure 2 shows typical tailings deposition snapshots for the second and fourth operational year. As noted above, the revised TMF layout does not significantly impact the tailings storage capacity, with the total reduction of about 3.5 million tonnes reduction at the ultimate configuration. This

Hardrock Project Revised Tailings Management Facility Alignment December 9, 2016

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deficit in storage will be further evaluated and adjusted in the TMF during detailed engineering of the facility. There are no other impacts due to the change in the TMF layout. Figure 2 also shows the emergency spillway alignments. During the initial first and second year of operations, the emergency spillway will be provided from the south cell to the north cell area, as the north cell is not operational during these years. Starting in year 4 of operations, the emergency spillway will be relocated through the east dam south of the inner dam (Figure 2). The spillway channel downstream of the dam will be directed to the existing drainage area upstream of WC-O. In later part of the mine life the emergency spillway will be moved to its final location on the western side of TMF in preparation for closure. We trust this explanation meets with your current expectations. Please do not hesitate to contact us should you require any further information. Sincerely, Amec Foster Wheeler Environment & Infrastructure a Division of Amec Foster Wheeler Americas Limited Prepared by: Prepared by:

David G Ritchie, M.Eng. P.Eng. Prabhat Habbu, M.Tech.,P.Eng. Principal Geotechnical Engineer Associate Geotechnical Engineer Attachments: Figure 1: TMF Modified Configuration Figure 2: Tailings Deposition Plan snapshot for end of year 2 and 4 P:\2015\Projects\TC150320_Greenstone_HR_Detailed_Design\12_Deliverables\Memos\memo on setback\Final Issue\Letter to GGM\REISSUE 8 Dec\Hardrock TMF realignment (dec.9.2016).docx

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1. ALL ELEVATIONS, GRID COORDINATES AND

DIMENSIONS ARE IN METRES. GRID COORDINATES

ARE REFERENCED TO UTM NAD 83 ZONE 16 DATUM.

CONTOUR INTERVAL AT 1.0 M.

2. EXISTING GROUND CONTOURS PRODUCED FROM

LIDAR FLOWN MAY 27 2014, COMPILED BY KBM

RESOURCES GROUP.

3. EXISTING GROUND CONTOURS OUTSIDE OF LIDAR

MAPPING WERE RETRIEVED FROM LAND

INFORMATION OF ONTARIO PROVINCIAL DEM 20M

GRID SIZE, BY THE MNR (ONTARIO MINISTRY OF

NATURAL RESOURCES)

4. THE OPEN PIT, WASTE ROCK AREA AND PLANT SITE

LAYOUTS WERE PROVIDED BY PREMIER (NOVEMBER

2014)

CONTOUR

WATERCOURSE

RAILWAY LINE

WOODED AREA

MINING CLAIM OWNERSHIP BOUNDARY

MUNICIPAL BOUNDARY

COMMUNICATION LINE

TMF DAM CENTRELINE

PROJECTION:

DATUM:

TITLE

PROJECTCLIENT LOGO

FIGURE No.

160 Traders Boulevard East

Mississauga, Ontario, Canada L4Z 3K7

Amec Foster Wheeler Environment & Infrastructure

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CLIENT:

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HARDROCK FEASIBILITY STUDY

TAILINGS MANAGEMENT FACILITY

ULTIMATE TMF ARRANGEMENT PLAN

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ZONE 16

AS SHOWN

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PROJECTION:

DATUM:

TITLE

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FIGURE No.

160 Traders Boulevard East

Mississauga, Ontario, Canada L4Z 3K7

Amec Foster Wheeler Environment & Infrastructure

REV. NO.:

PROJECT NO:

CLIENT:

DWN BY:

CHK'D BY:

DATE:

SCALE:

COMPANY LOGO

GREENSTONE GOLD MINES

HARDROCK FEASIBILITY STUDY

TAILINGS MANAGEMENT FACILITY

TAILINGS DEPOSITION SNAPSHOTS

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UTM NAD 83

ZONE 16

AS SHOWN

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