Hardrock Project - Conceptual Closure Plan

Transcription

1 Hardrock Project - Conceptual Closure Plan Prepared for: Greenstone Gold Mines GP Inc. 365 Bay St, Suite 500 Toronto, ON M5H 2V1 Prepared by: Stantec Consulting Ltd. 70 Southgate Road, Suite 1 Guelph, ON N1E 7B8 File No

2 Table of Contents ABBREVIATIONS... IV 1.0 INTRODUCTION LEGISLATIVE REQUIREMENTS CLOSURE OBJECTIVES KEY STAKEHOLDERS PROJECT INFORMATION PROPONENT INFORMATION LAND TENURE CURRENT SITE CONDITION LAND USES HISTORICAL MINING OPERATIONS TOPOGRAPHY SURFACE WATER GROUNDWATER TERRESTRIAL PLANT AND ANIMAL LIFE AQUATIC HABITAT AND FISHERIES PROJECT DESCRIPTION OPEN PIT UNDERGROUND MINE INFRASTRUCTURE MATERIAL STORAGE Topsoil and Overburden Removal and Storage Removal of Contaminated Materials Waste Rock Borrow Sources Ore PROCESSING PLANT TAILINGS MANAGEMENT FACILITY (TMF) BUILDINGS AND INFRASTRUCTURE Buildings Infrastructure PROGRESSIVE REHABILITATION CONSTRUCTION-RELATED BUILDINGS AND LAYDOWN AREAS WASTE ROCK STORAGE AREAS OVERBURDEN STOCKPILES TAILINGS MANAGEMENT FACILITY SATELLITE OPEN PIT SCHEDULE

3 6.0 REHABILITATION MEASURES FINAL CLOSURE OPEN PITS Refilling the Main Open Pit with Water Historical Underground Openings Stability of Subsurface Workings TAILINGS MANAGEMENT FACILITY Dam Safety and Operation Slope Stabilization Vegetative Cover Drainage WASTE ROCK STORAGE AREAS OVERBURDEN STOCKPILES REMOVABLE INFRASTRUCTURE, EQUIPMENT, AND MATERIALS REVEGETATION EFFLUENT WATER QUALITY CONTINGENCY MEASURES Wetland Treatment SCHEDULE MONITORING PHYSICAL STABILITY MONITORING Open Pit and Mine Openings Tailings Management Facility Overburden and Waste Rock Storage Areas Water Management Structures Surface Structures CHEMICAL STABILITY MONITORING Surface Water Monitoring Groundwater Monitoring BIOLOGICAL MONITORING Aquatic Monitoring Program Terrestrial / Wildlife Monitoring Program EXPECTED SITE CONDITIONS POST-CLOSURE LAND USE SITE TOPOGRAPHY LOCAL SURFACE WATERS AND RECEIVER WATERS Open Pit Goldfield Creek Golf Course Ponds Smaller Watercourses and Drainage Features Mosher Kenogamisis GROUNDWATER CONDITIONS TERRESTRIAL PLANT AND WILDLIFE COMMUNITIES AQUATIC HABITAT AND FISHERIES FOLLOWING CLOSURE

4 9.0 ABORIGINAL ENGAGEMENT AND PUBLIC CONSULTATION REFERENCES LIST OF TABLES Table 4-1: Waste Rock Storage Area Capacities and Geotechnical Design Parameters Table 6-1: Pit Water Quality at Time of Discharge Table 6-2: Closure Status of Mine Openings Table 7-1: Physical Stability Monitoring Requirements Table 7-2: Chemical Monitoring Parameter List Table 7-3: Groundwater Monitoring Plan LIST OF FIGURES Figure 1-1: Project Location Figure 1-2: Site Plan Figure 2-1: Land Tenure and Closure Boundary Figure 3-1: Historical Mine Openings and Tailings Areas Figure 3-2: Topography Figure 3-3: Surface Water Features Figure 4-1: Water Management During Operations (Mine Years 1-16) Figure 4-2: Open Pit and Waste Rock Storage Area Development Key Years Figure 5-1: Progressive Rehabilitation Schedule Figure 6-1: Water Management - Active Closure (Closure Years 1-5) Figure 6-2: Water Management Ongoing Pit Filling (Mine Years 6-56) Figure 6-3: Water Management After Pit Filling (Mine Years 56+) Figure 6-4: Final Closure Schedule

5 Abbreviations µg/l amsl ARD CDA CIP Code EA ECA EDF GGM ha IDF kt LNG LOM m MAC mg/l MMER MNDM MPA NAG NP ODWS OMS micrograms per litre above mean sea level acid rock drainage Canadian Dam Association carbon-in-pulp The Mine Rehabilitation Code of Ontario, as set out in Ontario Regulation 240/00 Environmental Assessment Environmental Compliance Approval Environmental Design Flood Greenstone Gold Mines GP Inc. Hectare Inflow Design Flood one thousand tonnes (metric) liquefied natural gas life of mine Metres Maximum Acceptable Concentration milligram per litre Mining metal Effluent Regulation Ministry of Northern Development and Mines maximum potential acidity non-acid generating neutralization potential Ontario Drinking Water Standards Operations, Maintenance and Surveillance O. Reg. Ontario Regulation

6 PAG PDA PHCs Premier PTTW PWQO SCS Stantec t TDS TMF tpd TSS WRSA Potentially Acid Generating Project Development Area petroleum hydrocarbons Premier Gold Mines Ltd. Permit To Take Water Provincial Water Quality Objectives site condition standard Stantec Consulting Ltd. tonne (metric) total dissolved solids tailings management facility tonnes (metric) per day total suspended solids waste rock storage areas v

7 Introduction 1.0 INTRODUCTION Greenstone Gold Mines GP Inc. (GGM, the Proponent), a joint venture partnership between Premier Gold Mines Ltd. (Premier) and Centerra Gold Inc., proposes the construction, operation, decommissioning, and closure of an open pit gold mine and associated ancillary activities, collectively known as the Hardrock Project (the Project). The Project is located in the Municipality of Greenstone, Ontario, in the Ward of Geraldton, at the intersection of Highway 11 and Michael Power Boulevard (Figure 1-1). The Project is situated within a historical mine area that includes the former Hardrock and MacLeod-Cockshutt Mines. The MacLeod-Cockshutt Mine underwent a number of name changes and is referred to as the MacLeod-Mosher Mine in this report. The Hardrock and MacLeod-Mosher Mines operated during the s. Premier acquired the mining claim in December 2008 for the area and completed a number of exploration programs. In 2012, a Closure Plan and associated addenda were submitted to the Ministry of Northern Development and Mines (MNDM) for an advanced exploration program involving the dewatering of the historical underground working and installation of a ramp to access the underground for advanced exploration (Premier, 2011). The Closure Plan was accepted by the MNDM on April 5, 2012, but the advanced exploration program was not implemented as plans were modified to focus on on-going exploration from surface and the advancement of planning for an open pit mine. The mine plan for the open pit mine includes a main open pit and a satellite pit, ore processing facilities including crushing plants and ore milling and processing plant, waste rock storage areas (WRSAs), tailings management facility (TMF), natural gas-fueled power plant and associated infrastructure, liquefied natural gas (LNG) plant, explosives manufacturing and storage facility, and other associated buildings and processes. Project activities include the relocation of existing infrastructure currently located within or adjacent to the Project development area (PDA) (Figure 1-2). GGM has retained Stantec Consulting Ltd. (Stantec) to carry out a Federal and Provincial Environmental Impact Statement/Environmental Assessment (EIS/EA) for the Project. This Conceptual Closure Plan has been prepared to support the EA and provides preliminary details on the progressive rehabilitation and closure plans for the Project. 1.1 LEGISLATIVE REQUIREMENTS The requirements of a closure plan are set out in the Ontario Mining Act, R.S.O. 1990, c. M.14 (Mining Act), and the Mine Rehabilitation Code of Ontario, as set out in Ontario Regulation 240/00 (O. Reg. 240/00). 1.1

8 Wabakimi Manitoba Ontario _ ^ Québec ± O'Sullivan Esnagami Project Location Minnesota Wisconsin Iowa Toronto Michigan New York Illinois Cochrane District Thunder Bay District MUNICIPALITY OF GREENSTONE Nipigon Geraldton Longlac Pagwachuan _ ^ 11 V U Project Location Long W:\active\ \drawing\MXD\EA\APC\Reports\ClosurePlan\ _Fig_1_1_ProjectLocation.mxd Revised: By: dharvey Nipigon 17 V U White Marathon V U V U V U Thunder Bay Superior 61 U V 0 1:1,600,000 Legend _ ^ Notes 1. Coordinate System: NAD 1983 UTM Zone 16N 2. Base features produced under license with the Ontario Ministry of Natural Resources Queen's Printer for Ontario, ,000 Project Location Town/ Village City Highway Client/Project Canada/ U.S.A Border District Boundary Municipal Boundary Waterbody 40,000 m Greenstone Gold Mines GP Inc (GGM) Hardrock Project Figure No. 1-1 Title Project Location

9 W:\active\ \drawing\MXD\EA\APC\Reports\ClosurePlan\ _Fig_1_2_SitePlan_ mxd Revised: By: dharvey!!!! Goldfield ! T1 ^_! A-321 T2 ^_!!!!!!!!!!!! Trans-Canada Highway 11 Longacre Goldfield Road " GFP1 -V W C " GFP3 GFP2 " Goldfield Creek Tributary North Branch WC-S WC- R WC- U A A-322 " D! Marron GFP4 ^_ S1 WC- Q!!!! Pond T2 Inner Dam G ol dfie!!!!! r ld Creek T i butar y WC- H S4 ^_!? D Goldfield Cr e ek Kenogamisis SWP1!!!!!! " Pond T3 S3 Pond T1 ^_ WC-L D " WC- Z SWP3 SWP2 WC- O WC- B!=!!!!! T WC- M!!!!!!!! SWP4 D Lahtis Road D Waste Rock D (Contingency) OldArena Road " D " ^_ Barton Bay (West) S2 Pond A D!!!! Mosher D! Process Plant Area Collection Pond Pond M1 Puppy #0 "S!!!!!! Pond D2 ")! Pond C2 Waste Rock C Waste Rock D!!!!!!!! "S To Geraldton!!! CC!! Michael Power Blvd. Pond C1!! Rosedale Point!!!!!!!!!* OP P!!!! Waste Rock AC (Contingency) SW Arm WC- A!! Tributary! Pond D1 Kenogamisis (Southwest Arm)!!!! #0!(ñ WC- C D Pond A1 A_Tailings Waste Rock B Pussy!!! Barton Bay (East) Pond A4 Pond A2!! Mine Effluent and Sanitary Sewer Outfall Location! Waste Rock A "S!! A_Extension Pond A3!! Kenogamisis (Central Basin) The Lago MACLEOD PROVINCIAL PARK McKelvie km 1:36,000 ± Project Legend Development Area!(ñ Notes 1. Coordinate System: NAD 1983 UTM Zone 16N 2. Base features produced under license with the Ontario Ministry of Natural Resources Queen's Printer for Ontario, *. Existing Features have been removed in the PDA and Client/Project Figure No. Title Preliminary Site Plan ^_ "S!? #0! do not reflect current conditions. Greenstone Gold Mines GP Inc. (GGM) Hardrock Project 1-2 Borrow Source; T= Till & S= Sand Dewatering Raise/ Pump Station Explosive Plant Fresh Water Pumping Station Potential Information Center!* OP P Potential OPP Station T Outfall Location Proposed MTO Yard ")! Mine Camp D Watercourse Crossing "S Project Substation 115kV!= New Longlac TS 115kV Access Road Construction Access Road Goldfield Creek Diversion Dam Diversion Channel Fresh Water Pipeline Haul Road!! New Power Line 115kV Power Line Realignment!! 44kV Tailings Pipeline and Overhead Powerline TMF Inner Dam Inundated Area In Pit Dumping- Waste Rock Open Pit- Full Extent Ore Stockpile Process Plant Area Collection Ponds Tailings Managment Facility Waste Rock Storage Area Site Plan Highway Realignment New Highway 11 Alignment Existing Features* #0 Consolidated Mosher Long Lac Historic Shaft Highway Major Road Local Road!! Existing Power Line Watercourse Residual Historic Tailings Mosher Pit Provincial Park Waterbody Wetland (Eco-Site Based) Wetland (Unevaluated- MNRF Data) Historic Tailings Areas Hardrock Tailings Little Long LacTailings MacLeod High Tailings MacLeod Low Tailings

10 Introduction This Conceptual Closure Plan is not intended to meet all the requirements for a certified closure plan as required under Part VII of the Mining Act, but is provided to support the EIS/EA process and to initiate consultation in support of the development of the certified Closure Plan for the Project. The Conceptual Closure Plan provides the overall closure objectives for the Project and preliminary details on the proposed progressive rehabilitation and final closure activities to meet the expected site conditions after closure for the Project. An outline of anticipated monitoring during closure is provided and will form the basis for determining when final close out of the Project is achieved. 1.2 CLOSURE OBJECTIVES The primary objectives of rehabilitation and closure activities are to establish a Project site that is: self-sustaining; physically, chemically, and biologically stable; meets effluent surface water and groundwater quality criteria; revegetate areas of ground disturbance, where practical; meets the desired end land use and function, as it is defined through ongoing discussions with key stakeholders; and meets applicable regulatory requirements, including O. Reg. 240/00 as set out in Part VII of the Mining Act. At the end of mining operations, the main features requiring closure will include the main open pit, water management and drainage systems, WRSAs, TMF, site access roads, and buildings and associated infrastructure. After the closure works have been completed, a post-closure monitoring program, detailed in Section 7.0, will be carried out to verify that the closure objectives and criteria have been met and confirm that the Project can proceed to final close out status. 1.3 KEY STAKEHOLDERS The key stakeholders who potentially having an interest in, or may be affected by, the Project were identified early in the consultation efforts. The key stakeholders include: Municipality of Greenstone; Aboriginal communities; property owners in the immediate vicinity of the Project site; residents and business owners in the Municipality of Greenstone, particularly those in the Ward of Geraldton; non-government organizations and groups with interest in the Project; 1.7

11 Introduction local users of the land, including hunters, trappers, and fishermen; and agencies with an interest in the Project, including the Government Review Team, municipal representatives and planners. Prior to developing a certified closure plan, the post-closure land use and function will be better defined through ongoing consultation with the project stakeholders. The end land use may include recreational activities such as hunting, hiking, snowmobiling and other passive activities, as well as economic uses such as forestry. 1.8

12 Project Information 2.0 PROJECT INFORMATION 2.1 PROPONENT INFORMATION The Proponent of the Project is GGM. Contact information is as follows: Name of Proponent: Mailing Address of Proponent: Contact Person: Project Site Location: Greenstone Gold Mines GP Inc. 365 Bay St Suite 500 Toronto, Ontario M5H 2V1 Phone: (416) Fax: (416) Ian A. Horne, Director Environment and Community Relations Municipality of Greenstone District of Thunder Bay The Project is centred at the intersection of Highway 11 and Michael Power Boulevard. The centroid coordinates of the open pit are: UTM- Easting, , UTM-Northing ; Decimal Degrees, Long Lat ; Degrees Minutes Seconds, W, N. 2.2 LAND TENURE Figure 2-1 shows lot and claim numbers, and the closure boundary. 2.1

13 TB12149 TB TB TB11488 TB TB TB10643 TB10644 TW97 TB10645 TB10225 TB TB TB10200 TB10213 TB10201 Li ttle Magn TB10206 TB10207 TB10204 Trans-Canada Highway 11 TB10216 TB TB10301 et Ma gn e TB11641 TB10571 TB10572 TB10955 t Cr e ek TB10399 TB10404 TB10405 TB10573 TB10302 TB10398 TB10421 TB10715 TB TB10684 TB10681 TB10683 TB10716 eek TB11012 TB10768 TB10845 TB10952 TB10845 TB10679 TB10682 TB10950 TB10769 TB10569 TB10689 TB10692 TB10570 TB10565 TB10559 TB10568 TB10568 TB10887 TB10560 TB TB10693 TB10560 TB10678 TB10055 TB10949 TB10606 TB10604 TB10050 TB10053 ek oad na R Are Old TB TB10049 TB H TB11879 TB TB11887 TB10060 TB10051 TB10059 TB11885 TB11886 TB10048 TB10046 TB10044 TB10058 TB10057 TB TB10047 TB10033 TB10042 TB10608 TB10032 TB10615 TB11016 TB10056 TB10616 TB10029 TB10030 TB10031 SW Arm Tri bu TB13987 TB10040 TB10036 TB9981 CL PART 5 TB9988 TB9992 WC-J 1 Major Road TB14484 Local Road TB10688 TB13253 TB9986 TB9989 TB9983 Watercourse- Intermittent TB10699 TB10023 TB20657 TB12633 TB9982 Watercourse- Permanent TB10699 Kenogamisis (Central Basin) TB9985 TB9985 TB10038 TB10035 TB10688 TB9984 TB9991 Contour Line (10 m intervals) TB10700 TB11015 TB9984 TB9990 TB10039 TB11014 TB9987 Waste Rock Area Highway TB11015 CL10830 PART 1 TB10197 Hard rock Roa d TB10037 TB11017 TB10041 TB10198 Tailings Managment Facility TB11013 TB13986 TB10041 TB10482 M-304 TB10045 Process Plant Area (see detailed drawing) Waterbody TB12635 TB12634 TB12632 Mining Tenures and Claims Status Premier Gold Mineral Rights Only TB12492 TB12639 TB9983 TB12489 Premier Gold Staked Mining Claims TB Premier Gold 100% Surface and Mineral Rights TB9983 Premier Gold Leased Claim Mineral Rights Claim Pending tar y W C -M TB11889 WC-L WC TB10052 TB10061 M ck en zi e re C TB10065 Barton Bay (East) TB10042 TB10481 TB10483 TB14507 TB10914 TB10564 TB10563 Closure Boundary and Surface Claims Open Pit- Full Extent TB11348 TB10915 TB10607 TB10605 TB10064 TB10557 TB10886 TB10562 Legend Kenogamisis (Outlet Basin) TB11348 TB10621 TB10561 TB10591 TB10567 TB10566 TB10592 TB10556 TB10693 TB10591 TB10593 TB10055 TB10054 dr TB10558 TB10558 TB10561 TB10693 TB10692 Har reet h St Edit CL1844 TB10694 TB10691 TB10691 TB10677 TB10569 TB10691 TB10690 TB10717 TB TB10845 TB10623 TB10601 TB10951 TB10844 TB10624 TB10680 TB10685 TB10686 TB10767 TB10624 ± TB10957 TB10843 TB10844 CLM203 TB10403 Geraldton TB10959 TB10843 TB10598 TB10953 TB10402 TB10625 TB10602 TB10954 TB TB10397 TB TB TB10600 TB10603 TB10958 TB10848 TB10599 TB TB10396 TB10847 TB10846 TB TB10400 Cr TB20029 TB10205 TB11255 CLM395 TB10203 TB10215 TB TB10202 TB11839 TB11840 TB11254 TB10199 TB10212 TB10648 TB10226 TB10211 TB11487 k Creek oc TB TB TB10646 TB10647 TB TB TB r TB11252 TB TB C TB12148 TB12147 TB TB e TB11253 TB12146 TB12145 nn eet D io Main S tr k ee Road ee k Kenogamisis (Southwest Arm) Ontario _ ^ Goldfield Québec Project Location Minnesota Wisconsin Iowa d iel ld f Go Cr ee ri b kt r uta y k La ec reek Illinois ake py L C r ee Coordinate System: NAD 1983 UTM Zone 16N 2. Base features produced under license with the Ontario Ministry of Natural Resources Queen's Printer for Ontario, k Client/Project am i nt Greenstone Gold Mines GP Inc. (GGM) Hardrock Project 0 ee k 1 1:50, Cr New York 1. Figure No. re Pa Toronto Notes sis Ri ve r Pu p Michigan ss y Pu K enog W:\active\ \drawing\MXD\EA\APC\Reports\ClosurePlan\ _Fig_2_1_ClosureBoundary_ mxd Revised: By: dharvey s Lahti ol Cr G ld ie ad Ro df ld ie df ol G Manitoba Km 2-1 Title Closure Boundary and Surface Claims

14 Current Site Condition 3.0 CURRENT SITE CONDITION This section provides a brief overview of the condition of the Project site, shown in Figure 1-2. For the purposes of describing the conditions within the anticipated area of physical disturbance associated with the construction and operation of the Project, the term Project Development Area (PDA) is used. 3.1 LAND USES Existing land uses in the area include urban and rural uses, and are located on a mix of patent and Crown lands. Urban uses in and adjacent to the PDA are concentrated in Geraldton and local townsites established during previous mining activities. Mining and forestry activity in the area has influenced land and resource use. In the early 1930s, the region became known for gold mining; however, extraction ceased by the end of the 1970s, leaving forestry as the main industry and land use in the region. Today, the most extensive land uses are forestry, tourism and consumptive recreation such as hunting (including black bear, game birds, waterfowl, and hares), trapping, fishing (Walleye and Northern Pike), golf, and tourism. MacLeod Provincial Park is an important recreation area, located about 350 m to the east of the PDA, which offers opportunities for fishing, swimming, boating, canoeing, biking, picnicking and bird-watching. Other outdoor recreation infrastructure in the Municipality include canoe routes and boat launches, hiking trails, cross-country skiing trails and a network of snowmobiling trails that connects towns in the Municipality. The Kenogamisis Golf Club, located south of Geraldton and northwest of the MacLeod Townsite, is an 18-hole course that is operated by the Municipality. GGM owns the lands that the golf course is constructed on and currently leases the land to the Municipality. More details related to traditional land and resource use are presented in the Socio-Economic Background Study Report (Stantec 2015a). 3.2 HISTORICAL MINING OPERATIONS The Project is located within a historical mine area that was actively mined between the 1930s and 1970s by two mines known as the MacLeod-Mosher and Hardrock Mines. The MacLeod- Mosher and Hardrock Mines represent two of the most productive mines in the Geraldton gold mining camp, which was host to twelve mines at its peak in the mid-1940s. Details related to historical mining in the area, including a summary of historical rehabilitation efforts and environmental conditions, are provided in Stantec (2016a). 3.1

15 Current Site Condition Since mining ceased in 1970s, decommissioning and remediation activities have been completed at the former Hardrock and MacLeod-Mosher Mines. Surface infrastructure associated with these underground mines has been removed, with the exception of the former headframe, referred to as the McIntyre headframe, various mine hazards (shafts, a glory hole, raises, etc), and tailings areas. Two tailings areas associated with the former mines are located within the PDA and are referred to as the MacLeod High/Low tailings and Hardrock tailings. A third tailings area, the Little Long Lac tailings, is located north of the PDA. Figure 3-1presents the location of historical tailings areas and mine openings. Various characterization and rehabilitation works have been completed at the historical mine sites between 1988 and With the exception of the western portion of the historical Hardrock tailings, acid rock drainage (ARD) conditions are unlikely for the majority of the tailings areas. Groundwater and seepage water quality associated with the tailings is poor (especially with respect to arsenic) and has had an effect on water quality in Kenogamisis (see Section 3.4). 3.3 TOPOGRAPHY The topography is relatively flat to gently rolling with local relief up to 20 m (Figure 3-1). The ground surface slopes from topographic high areas dominated by bedrock outcrops to low lying areas characterized by swamps and ponds with overall poor drainage throughout the area. Ground elevations range from lows of about 335 m above mean sea level (amsl) along the shoreline of Kenogamisis and increases to 375 m amsl in the southwest. 3.2

16 ± ProjectDevelopmentArea Barton Bay (West) #0 Little Long Lac Mine Shaft 584 Highway WC- A Barton Bay (East) Historical Mines #0 #0 #0 #0 Consolid a ted MosherL ong L a c Ha rd Rock Gold Mine L ittle L ong L a c Mine S ite Ma cl eod -CockshuttMine Ta iling sdisposa l Pipeline a nd Trestle Area sof Exca va tion(ma cl eod -Cockshutt-1996) Existing Features Legend WC- C ContourL ine (2m Interva lsl id a rba sed ) Hig hwa y Ma jorroa d L oca l Roa d Wa tercourse-perma nent Old Arena Road Wa tercourse-intermittent Provincia l Pa rk Wa terb od y Wetla nd (Eco-S ite Ba sed) Wetla nd (U neva lua ted -MNRFDa ta ) W:\ a ctive \ \ dra wing \ MXD\ EA\ APC\ Reports\ ClosurePla n\ _ Fig _ 3_ 1_ Historica ll a ndu ses_ mxd Re vise d : By:d ha rvey Pond A WC- G Mosher WC- F SW Arm Tributary SWP4 Km 1:15, #0 Mosher No. 1 Shaft Trans-Canada Highway GCP-1 WC- E Michael Power Blvd. GCP-2 GCP-3 MacLeod Waste Pass #0 #0 MacLeod- No. 1 Shaft MacLeod- No. 2 Shaft MacLeod - No 2 Crusher Raise (Buried) #0 #0 #0 #0 #0 #0#0 MacLeod - Full Raise (Buried) MacLeod - North Zone Raise (Concrete Cap) WC- GH WC- J Hardrock Road MacLeod - Vent Raise (Concrete Cap) WC- D Glory Hole Hardrock Glory Hole MacLeod - East Raise (Concrete Cap) #0 Kenogamisis (Southwest Arm) WC- I Hard Rock- No. 2 Shaft WC-J Hard Rock- No. 1 Shaft #0 Kenogamisis (Central Basin) Location of Historic Arsenic Studies Notes Client/Projec t Greenstone Gold MinesGPInc (GGM) Ha rd rock Project Figure No. 3-1 P.J.Brug gera nd Asocia tes,2011.ha rd rock Project Ma cl eod MosherDewa tering Prog ra m:arsenic Concentra tionsins oil withinthe ProjectFootprint.Memo totim Twomey,S eptember2011. S ENES Consulta ntsl imited (S ENES ),2002.S umma ry of 1997to1999S ite ActivitiesForthe Reha bilita tionof The Mill/Roa sterarea sof the L a c PropertiesIncorpora ted Ma cl eod -CockshuttS ite,gera ld ton,onta rio.prepa red fortory Tory DesL a uriers& Binnington,April Historic Tailings Areas Ha rd rock Ta ilings Ha rd rock Rea ctive Ta ilingsarea L ittle L ong L a cta ilings Ma cl eod High Ta ilings Ma cl eod L ow Ta ilings 1. Coordina te S ystem:nad 1983U TM Z one 16N 2. Ba se fe a turesprod uced und erlice nse with the Onta rioministry of Na tura l Resources Que en'sprinterforonta rio,2015. Title Historical Mine Openings and Tailings Areas Ja nua ry

17 Kenogamisis (Outflow Basin) " Barton Bay (West)! " ) Ar en! = _ ^ ad Ro ld fie W -V ld SWP1 C "WC - L oc dr WC- G Pond A oa k R Explosive Plant! Potential Information Center! = New Longlac TS 115kV WC- " SW Arm Tri but a Diversion Channel Haul Road Tailings Pipeline and Overhead Powerline WC -J 1 Inundated Area Open Pit- Full Extent Ore Pile In Pit Dumping- Waste Rock ry Process Plant Area (see detailed drawing) Collection Ponds -N WC _ ^ GFP4 " " New Highway 11 Alignment -T WC " " GFP3 reek Goldfield C _ ^ WC- U Waste Rock Area Existing Features oa d Lahtis R GFP2 Tailings Managment Facility WC- M Contour Line (2 m Intervals Lidar Based) Kenogamisis (Southwest Arm) Contours (2 m intervals, approximate not survey grade) WC- O Highway GFP1 Major Road Local Road _ ^ Watercourse- Permanent Watercourse- Intermittent Waterbody Wetland (Eco-Site Based) A-321 Wetland (Unevaluated- MNRF Data) df ie ld W C-S C re ek Tr ib ut ar Notes W C- y No r th ol P G WC - Z Goldfield Access Road Construction Access Road S " S " Temporary Work Camp Project Substation 115kV Kenogamisis (Central Basin) d Proposed MTO Yard S " SWP2 _ ^ B ra nc 1. Coordinate System: NAD 1983 UTM Zone 16N 2. Base features produced under license with the Ontario Ministry of Natural Resources Queen's Printer for Ontario, h A-322 ldf i e l d o G y ar e ak Cre ek McKelvie L ek C re ut ib Tr ss y Q Client/Project Greenstone Gold Mines GP Inc (GGM) Hardrock Project Pu WC- R C- _ ^ W W:\active\ \drawing\MXD\EA\APC\Reports\ClosurePlan\ _Fig_3_2_Topography_Site_Plan_ mxd Revised: By: dharvey GH!? " Marron " o SWP3 SWP4 F D C- J T C- WC - S " Dewatering Raise/ Pump Station T! " ) I Borrow Source; T= Till & S= Sand S " WC - H W C- Ha r W G E W C- W. lv d rb Mosher Longacre B -C y1 1 C- Preliminary Site Plan _ ^ WC W e ow da Hig hw a Ol d ana Legend! ad lp s-c o ar WC- A ae ch Mi Tra n ± Barton Bay (East) Figure No A-323 Kenogamisis k Puppy C re e Puppy Pussy Title 0 1 1:36, km Topography

18 Current Site Condition 3.4 SURFACE WATER The Project is located in the southwest part of Kenogamisis River watershed on a peninsula in Kenogamisis, the main waterbody in the area, which is a long, narrow and shallow lake consisting of four major basins: Barton Bay Basin, the Central Basin (sometimes called MacLeod Basin), the Southwest Arm, and Northeast Arm (Outlet Basin), as shown on Figure 3-2. The Kenogamisis River is the main watercourse that flows into Kenogamisis at the southern end of the Southwest Arm. The Kenogamisis River originally flowed northeast to the Albany River and then to James Bay. The Long Diversion project, completed in 1939, diverted most of the flow from the Kenogamisis River into the Aguasabon River, which ultimately discharges into Superior. While the vast majority of the flow from Kenogamisis ultimately reports to the Aguasabon River and Superior, a minimum flow of 2 m 3 /s is maintained from the Saturday before Victoria Day (last Monday before May 25 th ) until Labor Day (1 st Monday in September) to continue to flow toward the Albany River. No numeric value has been set for a minimum flow at the Kenogamisis Diversion Dam for the remainder of the year (OPG, 2013). The Kenogamisis Dam, located at the northern end of the Outlet Basin, controls the water flowing out of Kenogamisis in accordance with the Aguasabon River System Water Management Plan (OPG, 2013). The operating plan for the Kenogamisis Dam specifies a normal operating water level range for the lake between m amsl and m amsl with two cautionary compliance zones established to allow some water level variability under winter and spring conditions. In addition to the Kenogamisis River, there are several streams and lakes that directly contribute flow to Kenogamisis within the immediate vicinity of the Project, including: Goldfield and Creek, Magnet Creek, Marron Creek, Mosher, Longacre, Puppy, Pussy, and Hardrock Creek as well as several smaller unnamed creeks and lakes. Figure 3-3 identifies the surface water features at the Hardrock Project site. Over time, metals concentrations in Kenogamisis have decreased. Before 1990, levels of cadmium, cobalt, lead, copper, arsenic, iron and phosphorus commonly exceeded the Provincial Water Quality Objectives (PWQO). However, since 1990, only iron and phosphorus have routinely exceeded the PWQO with arsenic above the Interim PWQO. There has been very little change in concentrations of these parameters over the 40 year record (Stantec 2016c). Additional details related to the surface water hydrology and water quality are presented in the environmental baseline reports for the Project (Stantec, 2016b and 2016c). 3.7

19 Burrows River rro Bu R ws o hm As iver Re e Volcan WC Dionne sor ± ek Cre -W Legend Major Road Local Road Ashmore Porthos re ek ck H ar d D ion ne Permanent Watercourse Waterbody ro sh ed tl ak e W s/ at S So er t. ut sh La hw ed w es re te nc rn e/h ud so n Ba yw at er WC-Y Direction of Flow Intermittent Watercourse C Ess Project Development Area Highway WC - X Wildgoose ek re C re Watersheds (Per MNR Mapping) Watershed (Primary) Cre ek Subwatershed Mag n e t Cre Watershed Geraldton ek WC- A ek re itt L le Ma g net C Crabtree Magnet W C -B Mosher Longacre W WC ek C re z ie C -V -G C- W C- E F GH W WC SW Arm Tri WC-L WC - bu C J -D W C- I Eldee WC-J 1 tary WC - N -M W -H C- T WC W C- O ld Cre e k W WC- U fi e Goldfield d -Z l Go WC P re e k y ke La y McKelvie ke Pupp y La C reek Puppy Pussy Notes 1. Coordinate System: NAD 1983 UTM Zone 16N 2. Base features produced under license with the Ontario Ministry of Natural Resources Queen's Printer for Ontario, Client/Project Little Nye Greenstone Gold Mines GP Inc (GGM) Hardrock Project Ke no gam isis R ive ek re C e ar Pu Cr ut ib Tr ek C Q C- iel d G oldf W R r WC- ss WC- T riplet CW S W:\active\ \drawing\MXD\EA\APC\Reports\ClosurePlan\ _Fig_3_3_SurfaceWaterFeatures_ mxd Revised: By: dharvey Mc n Ke C W Marron ) (11 ighway anada H Trans C W C- C G re a Parent Creek Calong :80,000 3 km Nye Figure No. 3-3 Title Surface Water Features

20 Current Site Condition 3.5 GROUNDWATER Overburden soils are characterized by silty to sandy calcareous till and glaciolacustrine and glaciofluvial deposits of clay and silt to sand, ranging in thickness from less than 1 m to greater than 20 m with an overall average of 6 m. Groundwater flow within the overburden and shallow bedrock is a subdued version of the ground surface, with localized groundwater flow systems controlled by topography. Shallow groundwater flow in the overburden and shallow bedrock is likely contained within each subwatershed, with overall regional flow towards Kenogamisis or toward surface water features that ultimately flow into the lake. Groundwater recharge occurs in the higher elevations to the west, and flows radially outward from topographic highs towards lower lying areas, where it discharges into wetlands, streams, or lakes. Additional details related to the subsurface conditions and groundwater flow and quality are presented in the environmental baseline reports for the Project (Stantec, 20156b and 2016d). 3.6 TERRESTRIAL PLANT AND ANIMAL LIFE The Project is located along the southern boundary of the Boreal Forest Region, in northern Ontario. Typical forest cover is a mix between deciduous and coniferous forest cover as well as coniferous swamp. White and black spruce, tamarack, balsam fir and jack pine are common with frequent occurrences of deciduous vegetation communities and species, including white birch, trembling aspen and balsam poplar. Wetland vegetation communities present in the PDA include swamp, marsh, bog, and fen community types. Many species of terrestrial features and associated functions were identified within the LAA and PDA and are typical of those expected to be in the Boreal Region. These features included: Protected Areas; Federal and Provincial Species at Risk (SAR); wetlands; and, provinciallysignificant wildlife habitat. Additional details related to the terrestrial and animal life are presented in the environmental baseline reports for the Project (Stantec 2015c and 2016e). 3.7 AQUATIC HABITAT AND FISHERIES s within the area of the Project provide coolwater habitat where there is an abundance of potential spawning habitat for Northern Pike and Yellow Perch. Important spawning and feeding habitat for species like Walleye and Whitefish were documented where the Kenogamisis River and Magnet Creek flow into Kenogamisis. Important spawning habitat for these species may also be provided by rocky mid-lake shoals in Kenogamisis and Goldfield. Moderate sized streams such as Goldfield Creek and its main tributary provided a variety of cover types and habitats, although riffle habitat was limited. These streams provided an 3.11

21 Current Site Condition abundance of potential Northern Pike spawning habitat in adjacent wetlands when they become inundated in the spring. Despite good cover, fish abundance and species diversity were low in streams. The exception to this was large numbers of small bodied fish that may use lower stream mouths to spawn. Shallow, isolated ponds and first order watercourses in the vicinity of the Project likely freeze to the bottom in winter, limiting fish use of these types of habitat. Highly organic substrates and ice cover may also create anoxic conditions in these areas, further limiting fish distribution. Additional details related to the aquatic habitat and fisheries are presented in the environmental baseline reports for the Project (Stantec, 2015d and 2016f). 3.12

22 Project Description 4.0 PROJECT DESCRIPTION The Project consists of an open pit mine with milling at up to 24,000 tpd during the first two years, increasing up to 30,000 tpd for the duration of mine life. Ore processing will be carried out by conventional methods using a combination of gravity separation and cyanidation for gold recovery, followed by in-plant cyanide detoxification using the SO2/air oxidation process. Recovered gold will be smelted into doré bars. The key components of the Project are expected to include, but not be limited to, the following: open pit mine; WRSAs; stockpiles; crushing plants and mill feed storage area; ore milling and processing plant; water management facilities; TMF; power supply and associated infrastructure; liquefied natural gas plant; explosives manufacturing plant and storage area; mine operation buildings; service water supply and associated infrastructure; sewage treatment; site lighting and security; mine-site roads and parking areas; watercourse crossings, realignments, and habitat compensation/offsets; onsite pipelines and piping; hazardous materials transportation and storage; borrow sources; and temporary mine camp. Figure 1-2 shows the location and general layout of the major Project components. Figure 4-1 shows the proposed water management scheme during operations (mine Years 1-16). 4.1

23 \\cd1220-f02\01609\active\ \drawing\graphics\corel\project_description_chapter\ _fig_4_8_waterbalance.cdr From Catchment Fresh Water Evaporation Precipitation Evaporation Seepage WRSAs Groundwater Recharge Mill Precipitation Evaporation Slurry Reclaimed Water Open Pit Sedimentation Mill Yard Pond Precipitation Stormwater Evaporation Runoff Runoff TMF Precipitation Barton Bay Ponds A1, A2, A3, C1, C2, D1, & D2 Runoff Dewatering Underground Mill Losses Workings Evaporation Precipitation Evaporation Evaporation Precipitation Equalization Pond M1 Water Runoff in Ore Runoff Process Plant Waste Rock Storage Tailings Area Evaporation Make Up Water Polishing Pond Slurry Water Dewatering Excess Excess / Make Up Reclaim Precipitation Effluent Discharge Evaporation Open Pit Evaporation South West Arm Runoff Sedimentation Precipitation Evaporation Pond Tailings Facility Groundwater Recharge Central Basin Effluent Treatment Plant Dam Seepage GW Seepage Precipitation Effluent To Outlet Basin From Catchment Locked in Water Southwest Arm of Kenogamisis Dam Seepage Client/Project December Greenstone Gold Mines GP Inc (GGM) Hardrock Project Figure No. 4-1 Title Water Management During Operations (Mine Years 1-16)

24 Project Description The following provides a summary of the main Project components that will be developed and require management through closure. Details for all Project components will be provided in the certified closure plan to be developed following completion of the feasibility level engineering. 4.1 OPEN PIT The main open pit and satellite pit have been designed to facilitate ore extraction and accommodate safe equipment operation. Pit design considerations include benches, haul roads, and limited waste rock backfill. At their fullest extent, the satellite pit and main open pit are estimated to be 254 m long, by 198 m wide, by 60 m deep; and 1,829 m long, by 900 m wide, by 590 m deep, respectively (Figure 1-2). To mine the main open pit, pre-stripping of the overburden on top of the deposit will be required to expose the mineralized zone. Overburden will be temporarily stored within the waste rock storage areas for future use during rehabilitation. High-grade ore close to the surface will be targeted during the initial years of operation, where feasible. This will be achieved by developing the main open pit in three phases, where mining phase 1 starts at the eastern portion of the main open pit with each subsequent phase extending westward. The phased mining approach reduces the area of ground disturbance during the earlier years of production. This approach also provides information on how the rock reacts to mining and informs the design of slopes as mining progresses. At Year 3, stripping of overburden will be undertaken to provide access to the mining phase 2 area. Mining phase 2 area opens access to the deeper portion of the ore body. Overburden stripping is planned in Year 5 for the mining phase 3 area, following which the whole open pit area is exposed at surface. The extent of open pit development for Years 3, 5, 8 and life of mine (LOM) is shown on Figure 4-2. Waste rock will be backfilled in the satellite pit as well as portions of the main open pit. Once mining of the satellite pit is complete, the pit will be backfilled with waste rock in approximately Year 9. Backfilling in the main open pit is only feasible in the east end in order to maintain ramp access into the west end of the pit. Two scenarios for in pit storage have been developed. In scenario 1, the overall slope of the in-pit storage pile will be 2H:1V with a total storage capacity of 20 Mt. For scenario 2, the overall slope would be 1.5H:1V with a total storage capacity of 68 Mt. Further work will be completed during detailed design to confirm the preferred scenario for backfill. 4.3

25 Lahtis Road Lahtis Road Barton Bay Barton (West) Barton Bay Year 3 Bay (West) (East) Year 5 Mosher A_Tailings Waste Rock A Mosher A_Tailings Barton Bay (East) Waste Rock A ± Legend Open Pit In Pit Dumping Trans-Canada Highway 11 Waste Rock C Trans-Canada Highway 11 Waste Rock C Waste Rock Area New Highway 11 Alignment Highway Major Road Local Road Watercourse Waterbody SW Arm Tributary SW Arm Tributary Kenogamisis (Southwest Arm) Waste Rock D Kenogamisis (Southwest Arm) Year 8 Barton Bay (West) Barton Bay (East) End of LOM Barton Bay (West) Barton Bay (East) A_Tailings A_Tailings W:\active\ \drawing\MXD\EA\APC\Reports\ClosurePlan\ _Fig_4_2_MineFootprint_KeyYears_ mxd Revised: By: dharvey Lahtis Road Mosher Trans-Canada Highway 11 Waste Rock C Waste Rock D Satellite Pit SW Arm Tributary Waste Rock B Kenogamisis (Southwest Arm) Waste Rock A Lahtis Road Mosher Trans-Canada Highway 11 Waste Rock C Waste Rock D CC SW Arm Tributary Waste Rock B In Pit Dumping Kenogamisis (Southwest Arm) Waste Rock A A_Extension km 1:32,000 Notes 1. Coordinate System: NAD 1983 UTM Zone 16N 2. Base features produced under license with the Ontario Ministry of Natural Resources Queen's Printer for Ontario, Client/Project Greenstone Gold Mines GP Inc (GGM) Hardrock Project Figure No. 4-2 Title Open Pit and Waste Rock Storage Area Development

26 Project Description 4.2 UNDERGROUND MINE INFRASTRUCTURE No new underground mine infrastructure is anticipated for the Project; however, existing historical underground workings will be used as a water management component. Dewatering will be carried out by pumping water from the MacLeod-Mosher and Hardrock Mine underground workings. Water from the underground workings will be used to meet mill reclaim demand with excess water treated if required and discharged to the Southwest Arm of Kenogamisis in accordance with regulatory approvals. Water inflows in the form of direct precipitation, surface run-off and groundwater seepage to the open pit will be directed to the historical underground workings associated with the MacLeod-Mosher and Hardrock mines via drainage shafts bored through the active pit floor. The use of the historical underground workings provides a storage reservoir for open pit seepage and runoff during the mining operation and allows for flexibility in the water management approach. Variations in pumping rates from the historical underground working will be used to help manage large storm and spring freshet runoff events when surface storage capacity is reduced, providing a buffering for peak flows requiring treatment and discharge. 4.3 MATERIAL STORAGE Topsoil and Overburden Removal and Storage It is necessary to remove topsoil and overburden in the open pit area to expose the bedrock so that mining can commence. Overburden will be removed in accordance with detailed designs for various Project components including building foundations, roads, TMF perimeter dams, and some limited areas where waste rock is deposited. An estimated 15.5 Mt of overburden will be generated over the LOM. The primary overburden stockpile will be located over the portion of WRSA A that is located on top of the Macleod historical tailings. The placement of additional overburden over the MacLeod historical tailings will result in reduced runoff and seepage from the historical tailings to groundwater and Kenogamisis throughout all Project phases. In addition, a smaller overburden stockpile will be developed within contingency area for WRSA D near the TMF for temporary storage until required for rehabilitation of the TMF, beginning in Year 10. Overburden is classified as non-pag and is unlikely to generate acidic leachate based on multiple lines of evidence (Stantec, 2015e). Leachates from kinetic tests are compliant with Schedule 4 of the Metal Mining Effluent Regulations (MMER), but indicate potential exceedances of the PWQO for arsenic and possibly cobalt and copper. The composite sample used in the kinetic testing likely overestimates the metal leaching potential of overburden as these samples may have been affected by historical mining operations. Groundwater quality monitoring data from locations outside of historical mining areas indicated generally good 4.7

27 Project Description water quality within the overburden suggesting limited leaching potential from the overburden soils Removal of Contaminated Materials Prior to construction, soils affected by historical activities that are located in the planned footprint of the process plant, open pit, and ancillary infrastructure will be removed or remediated. These areas include a portion of the MacLeod and Hardrock historical tailings currently situated over the main open pit, and if found, contaminated soils at the former MacLeod and Hardrock plant sites, gas station properties and other locations as they are identified. A Soil Management Plan will be developed for the Project to guide the storage and management of soils generated during construction of the Project. During pre-production, the historical tailings in the open pit mining area will not be disturbed until the new TMF is constructed. Contaminated material will be managed in accordance with the applicable regulations (O. Reg. 347 and O. Reg. 153/04) and the Soil Management Plan to be developed for the Project Waste Rock Waste rock will placed in a series of storages areas located in close proximity to the open pit. This includes four waste rock storage areas (WRSAs A, B, C and D) placed around the majority of the open pit perimeter while accommodating the ore milling and processing plant area and avoiding overprinting the Southwest Arm Tributary. A portion of WRSA A will also be extended into the open pit area during backfilling of the eastern-most area of the main open pit (Figure 1-2). A detailed Waste Rock Management Plan will be developed for the Project and will include plans for progressive development, mineralogical testing, and operational monitoring requirements to guide the management and reuse of waste rock generated during the Project. The location of the WRSAs were selected to be reasonably close to the open pit to reduce the overall Project environmental footprint, and to limit energy consumption and dust generation associated with shorter material hauling distances. The WRSAs have been designed to maintain short term and long term physical stability while maximizing the use of the limited area available surrounding the open pit. Based on the foundation conditions, segments of the WRSA embankments have been designed with average slopes of 2H:1V to 4H:1V. The footprints of WRSAs A, B, C, and D are approximately 133 ha, 79 ha, 116 ha, and 221 ha, respectively. Two contingency waste rock storage areas, Contingency AC and Contingency D (Figure 1-2), have been identified that would be used in the event that portions of the foundation conditions of primary areas are, based on conditions in the field, deemed not suitable for anticipated capacities as mining progresses. The contingency WRSAs may also be used in the event 4.8

28 Project Description additional waste rock is deposited to allow for a marginal increase in open pit size over time based on refinement to the mine plan as mining advances. Specifications for WRSAs and in-pit backfill are presented in Table 4-1, and the location of the WRSAs are shown in Figure 1-2. The general progression of waste rock deposition over time is shown in Figure 4-2. Table 4-1: Waste Rock Storage Area Capacities and Geotechnical Design Parameters Waste Rock Storage Area Capacity (kt) Height (m) Footprint (ha) Overall Slope (rise:run) Geotechnical Parameters Catch Bench Width (m) Bench Height (m) Bench Face Angle ( ) Active Dumping (Year) A 73, : to 3 A_Historic Tailings 27, : to 5 A_Extension 13, : B 87, :2 or 1:2.5 7 or to 11 C 80, : to 11 CC 42, : to 12 D 302, :2.5 to 1:3 12 to to 15 In-Pit 21, : to 13 Contingency AC 45, : n/a Contingency D 325, : n/a Borrow Sources Borrow sources will be developed to provide a local aggregate source to meet specific construction needs and maintenance of roads and pads, and other facilities as required. Locations of the proposed borrow sources are shown on Figure 1-2. Of the six sites identified, two sites could supply till and the remaining four would be used for granular materials. No excavation in the borrow sources is planned below the water table. Potential quantities available from each source include: Till area (T)1 : m 3 ; T2 : m 3 ; Sand area (S) 1 : m 3 ; S2 : m 3 ; S3 : m 3 ; and S4 : m

29 Project Description An aggregate plant (crushing and screening) will be required onsite during construction for earthworks (including road and foundation) and building construction. To meet future mine needs (e.g., road maintenance) for crushed aggregate, the portable crusher may remain onsite Ore Ore will be hauled from the open pit to one of two ore stockpiles, depending on the grade of the ore. The low-grade ore stockpile is partially located within the footprint of WRSA C and is expected to fluctuate in size throughout the life of mine, depending on production and operational needs, at times extending beyond the boundaries of this WRSA. The highgrade/medium-grade ore stockpile is located within the southwest portion of WRSA B (Figure 1-2). High-grade and medium-grade ore will be removed from the main open pit during Years -1 to 4 to be processed early during Project operations. As ore stockpiles are to be located within planned WRSA footprints, runoff from the stockpiles will report to the WRSA perimeter ditching and collection ponds as described in the Water Management Plan (Stantec 2016g). 4.4 PROCESSING PLANT The ore extracted from the main open pit will be crushed to a size and consistency that can be milled. Crushing is achieved using the following main components that are connected by an enclosed conveyor system at the east end of the processing plant: Primary Crusher: Primary crushing of the ore is achieved by using a gyratory crusher equipped with a dust collection system. The gyratory building has a single permanent opening over the gyratory crusher for truck dumping of ore into the process. Secondary Crusher: The secondary crusher receives crushed ore from the primary crusher via an overland conveyor. Secondary crushing is achieved by using a cone crusher, which is located within an enclosed building equipped with a dust collection system. Mill Feed Storage Area: The mill storage area receives crushed ore from the secondary crushing area via a conveyor system. The mill feed storage area is fully enclosed and will accommodate 47,000 tonnes of total ore capacity, with about one day of live storage for the mill at maximum throughput capacity. Ore will be transported from the stockpile to the mill by a conveyor system. The drawdown feeding systems under the mill feed storage area is equipped with a dust collection system. Conveyors between buildings, mill feed storage area, and mill will have protective covers to prevent fugitive dust and precipitation from falling on the material. The ore milling and processing plant is located west of the open pit (Figure 1-2), and planned to be constructed in two stages to accommodate an initial mining rate (mill phase 1 in Years 1 and 4.10

30 Project Description 2) and mill phase 2 throughput increase starting in Year 3. The process plant will cover approximately 1.39 ha, and will consist of the following equipment: grinding/milling equipment to reduce the size of the ore being processed (high pressure grinding rolls, screens, ball mills, cyclones); gravity concentration circuit equipment (centrifugal concentrators); leach and carbon-in-pulp (CIP) circuit equipment (pre-aeration tank, leach tanks, CIP tanks); gold recovery circuit equipment (carbon columns, electrowinning cells, reactivation kiln, furnace); and cyanide and tailings disposal equipment (cyanide detoxification tanks and tailings pipeline). Ore processing will be carried out by conventional methods using a combination of gravity separation and cyanidation for gold recovery, followed by in-plant cyanide detoxification using the SO2/air oxidation process. Doré gold bars will be produced at the end of the process. 4.5 TAILINGS MANAGEMENT FACILITY (TMF) An engineered TMF will be built to store mine waste in the form of tailings from the ore milling and processing plant and is located to the southwest of the processing plant (Figure 1-2). The TMF is expected to cover 518 ha (the north cell will have surface area of 162 ha and south cell will have a surface are of 356 ha) with an ultimate dam height of approximately 35 m. The twocell strategy has been developed to help with water management and progressive rehabilitation efforts for the Project. Additional details regarding the TMF design are provided by AMEC FW, September The TMF dams have been designed with a low permeability core along with filters and transitions zones upstream of the main embankment constructed of mine rock. The core will be constructed contiguously with foundation soil cutoffs that intercept sandy foundation soils. Foundation filters are provided under the rockfill to prevent piping of fines out of the foundation soils. Consolidation grouting of the upper fractured bedrock will be carried out where outcropping of shallow bedrock is encountered along the east side of the TMF. Tailings will be pumped to the TMF as conventional slurry (i.e., tailings and water) and discharged subaerially to the perimeter of the TMF via spigot arrays or end pipe discharge. The tailings solids will then settle out of the slurry, releasing a portion of the slurry transport water, and form a tailings beach. The slurry transport water, along with rainfall and runoff, will pool to form a supernatant pond. The supernatant pond will be operated to maintain a minimum beach length and minimum pond volume to meet process water demands. The primary source of process water for the mill will be obtained from the TMF supernatant pond with deficits in process water demands provided from contact and dewatering water (Stantec. 2016g). 4.11

31 Project Description To prevent dam failure under extreme weather events, an emergency spillway will be maintained such that the Inflow Design Flood (IDF) can be safely passed while maintaining minimum freeboard requirements. The Probable Maximum Flood (PMF) event is to be used for the IDF. Further, sufficient storage capacity will be maintained so that the Environmental Design Flood (EDF) can be stored in the TMF supernatant pond without discharging to the environment. A 100- year return hydrologic event (24-hour storm of freshet) EDF is the standard practice EDF for dams in Ontario. Dam runoff and seepage is captured in ditches downstream of the dams and pumped back to the TMF via three collection ponds (T1, T2, and T3). The ponds have been sized to contain runoff from the EDF (a 100-yr, 24 hour storm). In accordance with O. Reg 240/00, safety and management of the TMF will be addressed in accordance with the Canadian Dam Association (CDA) dam safety guidelines (CDA, 2013) and associated technical bulletins. In addition, consideration will also be given to the Ontario Dam Safety Guidelines developed under the Ontario Ministry of Natural Resources (MNR) s and Rivers Improvement Act (MNR, 2011), and associated technical bulletins. In addition, an Operations, Maintenance, and Surveillance manual will be developed, and followed, in accordance with the recommendations of the Mining Association of Canada (MAC) Guide to the Management of Tailings Facilities (MAC, 2011). 4.6 BUILDINGS AND INFRASTRUCTURE Buildings Site preparation will include the removal of existing infrastructure and contaminated material, clearing and grubbing, soil stripping, grading, and leveling of the site as required in preparation for foundations and buildings. Expected buildings to be constructed for the Project include: the process plant and mill, maintenance shop and warehouse, assay lab, mine dry and administration building, power plant, LNG plant, explosives manufacturing plant and storage, temporary mine camp, sewage treatment facilities, and effluent treatment plant Infrastructure Main access to the Project will be via the western leg of the existing Highway 11. This access point will be used by personnel and for material deliveries. The road will be maintained year round. Site haul roads will also be required to link the Project components. Large haul truck traffic and other site vehicular traffic will be separated, where feasible, to facilitate mining operation and increase internal road safety. Figure 1-2 shows the main roads planned for the Project. 4.12

32 Project Description There will be separate parking areas for mine employees and for the mine fleet. Parking areas for employees will be constructed at the main administration building, and the mine maintenance shop. No personal vehicles will be allowed on site. Mine fleet parking will be located just north of WRSA B. Parking areas will be graded, and finished with gravel. Several kilometres of pipeline and piping will be required on site to transport various materials throughout the PDA, including those described below: An onsite pipeline/piping system will connect various components to transport, treat and dispose of contact water, treated domestic water, and tailings between various facilities including the open pit, ore milling and processing plant, surface ponds, TMF, and sewage treatment facilities. This includes a dedicated tailings pipeline from the processing plant to the TMF, and a water reclaim pipeline from a pumping station near the TMF to the processing plant; A water piping system will connect to the municipal drinking water distribution system to provide potable water;. A natural gas piping system connected to the natural gas distribution pipeline will fuel the power plant and LNG plant; and, A piping system will connect to the pumping station at Kenogamisis to provide fresh water for process requirements and for discharge of water from the effluent treatment plant. All pipelines will be aboveground, with the possible exception of natural gas, sewage and potable water. The pipeline to the TMF will be constructed of high-density polyethylene with pressure gauges for leak detection. A safety pond with geomembrane for the tailings line will be constructed to contain 110% of the total pipeline volume. The calculated volume is approximately 1000 m³. To drain the tailings pipeline a fail-safe valve will be installed to open the line in case of electrical failure. The safety pond shall be kept empty with rainwater to be removed whenever accumulated. 4.13

33 Progressive Rehabilitation 5.0 PROGRESSIVE REHABILITATION Progressive rehabilitation will be completed, where possible or practical, throughout the mine operations and prior to closure. These activities that would contribute to the rehabilitation efforts that would otherwise be carried out after mining operations have ceased during closure. Once the mine advances from the development stage to the operational stage, progressive rehabilitation activities can commence where opportunities present themselves. Progressive rehabilitation opportunities for the Project during the operation phase may include: removal of construction-related buildings and rehabilitation of laydown areas and access roads used during construction; stabilization and revegetation, where practical, of WRSAs; rehabilitation of the north cell of the TMF, upon completion of deposition anticipated after Year 7, consisting of a vegetated store and release cover with runoff from the cell directed to the south cell, or to the environment once water quality meets acceptable regulatory requirements; backfilling of the satellite pit and partial backfilling of the eastern portion of the main open pit; and removal of hazardous and non-hazardous waste materials from site where possible on a regular basis. The following sections provide a summary of the anticipated rehabilitation efforts that will be completed during operations. 5.1 CONSTRUCTION-RELATED BUILDINGS AND LAYDOWN AREAS After the temporary mine camp is no longer required to support construction related activities it will be decommissioned, unless some other use is found for it in discussion with the municipality. The camp will be a series of single-story dormitory sections supported on cribbing placed on a prepared ground surface. The dormitory sections will be decommissioned and removed from site. Any foundations will be demolished to grade prior to final grading and placement of cover materials. Onsite infrastructure (e.g., pipelines, hydro poles, junction boxes, wiring, transformers and other electrical infrastructure) will be dismantled and removed from the temporary mine camp. Any other buildings, laydown areas or access roads not required during operation will be removed and any foundations will be demolished to grade prior to covering over. Efforts will be made to maximize the reuse of building materials, where possible, and any building material that cannot be reused will be recycled or disposed of in accordance with applicable regulatory requirements. 5.1

34 Progressive Rehabilitation Appropriate testing will be completed to confirm soil conditions are suitable for the intended land use and required remediation of affected soils will be completed if required in accordance with applicable regulations. The areas will be stabilized to prevent erosion and rehabilitated to a condition suitable for the intended land use. Areas that are to be returned to a naturalized condition will be covered with a minimum thickness (0.3 m) of suitable growth median (soil and topsoil) and allowed to revegetate naturally or by planting with appropriate native species. 5.2 WASTE ROCK STORAGE AREAS A detailed geochemical characterization program has been completed for the Project (Stantec, 2015e; 2016h). Approximately 550 Mt of waste rock will be generated over the LOM and has been classified into one of two categories: inert NAG; and reactive PAG. The estimated PAG waste rock accounts for less than 5% of the total waste rock mass (Stantec 2015f). A conservative estimate for potential ARD on-set is 15 years. As a result, ARD conditions are not expected during the operating stage of the Project (Stantec 2015e; 2016h). Metal leaching was identified as the primary concern with respect to water quality, particularly within the clastic sediments that represent approximately 72% of the waste rock. Geochemical testing during 2014 (Stantec, 2015e) indicated that there is the potential for elevated concentrations of arsenic, antimony and aluminum, and potentially iron, cobalt, uranium, chromium, and lead; however, these concentrations are not expected to exceed MMER. In 2015 field testing (Stantec, 2015h), metal leaching rates decreased by 2 to 5 times compared to 2014 for the main lithologies of waste rock and has had a significant impact on predicted water quality (Stantec, 2016g). The Waste Rock Management Plan will incorporate operational monitoring and testing to validate geochemical testing data and modelling predictions, providing an adaptive management approach to waste rock management. During construction of the WRSAs, grading will be completed to direct water from the piles down either the ramp or channeled sections of the slopes to promote runoff and reduce infiltration into the piles. At completion, minor re-contouring of the plateau will be carried out promote surface drainage and shedding of water from the piles, and the embankment slopes will be contoured (as required) to address the physical stability of the slopes. Once completed, the WRSAs will be covered with a storage and release cover to further reduce infiltration by promoting runoff and evapotranspiration. WRSA A will be the first pile to be rehabilitated beginning in Years 3 to 5 and will provide a test case for cover design for future piles, where rehabilitation does not begin to Year 11 of mine operations. The store and release cover will consist of a 0.5 m thick growth medium layer overlain by a 0.15 m thick layer of suitable composition to resist erosion based on the locations to be covered (i.e., plateau, slopes, benches). The store and release cover will be seeded to develop a vegetated cover to reduce erosion, increase evapotranspiration, and enhance natural revegetation of the piles. Soil tests and test plots will be carried out to confirm the best seed mixture as well as to identify requirements for mulching and fertilization. 5.2

35 Progressive Rehabilitation 5.3 OVERBURDEN STOCKPILES The overburden stockpiles will be developed early in the LOM as construction areas are prepared and stripping is completed for the open pit and construction areas. The overburden materials will be characterized and stockpiled based on material properties for re-use during progressive rehabilitation efforts in accordance with the Soil Management Plan and applicable regulatory guidelines. Once stockpiles are completed, they will be graded and seeded to minimize erosion. 5.4 TAILINGS MANAGEMENT FACILITY Ore processing will be carried out by conventional methods using a combination of gravity separation and cyanidation for gold recovery, followed by in-plant cyanide detoxification using the SO2/air oxidation process. Detailed tailings characterization and metallurgical testing were completed and documented in Stantec 2105e; 2016h). The estimated tonnage of PAG ore is Mt, corresponding to 9.7% of the total ore with an ARD on-set time of 13 years. Through the in-plant process, sulphides within the resulting tailings will be oxidized by approximately 26% in alkaline solutions reducing the overall PAG percentage of the tailings. Prior to rehabilitation efforts, testing of tailings beaches will be completed to determine if localized areas or pockets of PAG tailings exist due to preferential settling of sulphide minerals near final deposition locations. If required, remedial measures will be undertaken to mitigate ARD conditions during closure. Based on the deposition plan, the north cell is expected to reach capacity after Year 7 allowing for progressive rehabilitation of the north cell to occur during operations, reducing the volume of water under management. The north cell will be rehabilitated by lowering the supernatant pond elevation, constructing a spillway through natural ground at the northeast abutment to drain the surface of the cell, and placement of a store and release cover over the tailings beaches to create a barrier between the tailings surface and runoff. The store and release cover will be seeded to develop a vegetated cover to minimize erosion, increase evapotranspiration, and enhance natural revegetation of the cell. Soil tests and test plots will be carried out to confirm the best seed mixture as well as to identify requirements for mulching and fertilization. During the initial years following rehabilitation, water from the north cell will be directed to the south cell until water quality has been shown to consistently meet discharge criteria. This will provide time to test the effectiveness of the rehabilitation efforts, and make necessary modifications, if required, while under operating conditions. Once water quality meets the required discharge criteria, water from the north cell will be directed through the spillway to the head pond and out to the realigned Goldfield Creek tributary in accordance with regulatory approvals. 5.3

36 Progressive Rehabilitation 5.5 SATELLITE OPEN PIT The satellite pit will operate in Years 8 and 9. After Year 9, the satellite pit will be filled to surface with waste rock from the main open pit in accordance with the Waste Rock Management Plan and covered by WRSA C. 5.6 SCHEDULE The schedule for progressive rehabilitation activities is provided in Figure 5-1. The preliminary timelines associated with progressive rehabilitation are as follows: Year 3 to 5 removal of any buildings, infrastructure, and laydown areas associated with construction that will not be required during operation; Years 4 to 5 rehabilitation of portions of WRSA A; Year 7 rehabilitation of the north cell of the TMF; Years 8 to 9 rehabilitation of WRSA A over the historical tailings; Year 10 - backfilling the satellite pit with waste rock from the main open pit; Years 12 to 13 rehabilitation of WRSA B and C; and, Years 13 to 14 rehabilitation of WRSA CC. 5.4

37 Progressive Rehabilitation Figure 5-1: Progressive Rehabilitation Schedule Mine Year Construction, Mining, Processing Construction Main Open Pit Satellite Open Pit Process Plant Operation Infrastructure Removal Backfilled Ore Stockpiles Low Grade Medium and High Grade Waste Rock WRSA_A WRSA_A_Tailings WRSA_A_Extension WRSA_B WRSA_C WRSA_CC WRSA D In Pit Dumping Tailings North Cell South Cell Legend Active Closure / Rehabilitation Work Monitoring / Maintenance 5.5

38 Rehabilitation Measures Final Closure 6.0 REHABILITATION MEASURES FINAL CLOSURE After mining and processing operations are completed, the PDA will be rehabilitated and the Project will be move towards a final closed out condition. Active closure measures will be completed in the first five years following completion of operations and will include removal and decommissioning of Project infrastructure not required for long term closure and rehabilitation of the PDA in accordance with the requirements of O. Reg. 240/00. After the active closure period, ongoing closure monitoring and maintenance activities will be completed as required to address remedial efforts until stable conditions exist and the closure objectives have been satisfied. This is expected to occur in the first five years following closure. Beyond this time, filling of the open pit will represent the main closure activity, as the pit is anticipated to take approximately 56 years to fill once dewatering is terminated. Once the open pit has refilled and water quality has been demonstrated to meet acceptable regulatory criteria, the Project would be moved to a closed out status as defined in O. Reg. 240/00. The following sections provide details on the final closure activities that will be completed for the main Project components. 6.1 OPEN PITS O. Reg. 240/00 outlines a variety of strategies for rehabilitated and closure of open pits, which were considered in developing the preferred approach for the Project. As described in Section 5.5, the satellite pit will be rehabilitated by backfilling with waste rock during operations and as a result no further work will be required during the active closure period. The backfilling of the open pit represents the preferred strategy for open pit rehabilitation as defined in O. Reg. 240/00. For the main open pit, only a partial backfill option is viable as the long term potential of further exploration and development of the underground portion of the Project has not been determined. Backfilling of the pit with waste rock would have an effect on future access points to the historical underground workings and create long term challenges for future underground mine development if determined to be feasible. As a result, allowing the open pit to refill with water, creating a pit lake was selected as the preferred closure option. The overburden slopes around the open pit should be resloped to a grade of 3H:1V or flatter so that riparian vegetation can be established along the shoreline where possible. As indicated by O. Reg. 240/00, open pits must be secured from inadvertent access with different security measures potentially used for different stages of the mine life (construction, operation, inactivity, temporary suspension, closure, post-closure). Access to the Project is to be restricted during construction and operations by a steel chain-link fence and managed by site security services. At closure, access and security around the open pit will be restricted by the installation of a 2 m high boulder fence around the main open pit and WRSAs. 6.1

39 Rehabilitation Measures Final Closure Refilling the Main Open Pit with Water A groundwater flow model was developed to estimate the time for the main open pit water levels to recover from groundwater inflows. It was found that recovery would take over 200 years. To expedite the refilling of the open pit, enhanced refilling operations are planned and include pumping water from the TMF for five years following closure and directing surface water from the various mine water collection ponds to the open pit, in addition to the taking of water from Kenogamisis. These efforts reduce the final open pit filling time to 56 years. Figure 6-1, Figure 6-2, and Figure 6-3 show the proposed water management scheme for closure Years 1 to 5, 6 to 56, and after Year 56, respectively. These figures assume that the WRSA ponds continue to be pumped to the open pit until the pit has filled with water. Directing water from the TMF to the open pit during the first five years of closure allows for final rehabilitation efforts to be carried out at the TMF and for water quality to improve to conditions which meets applicable regulatory criteria. After water quality has been shown to meet discharge criteria, effluent will be discharged directly to the environment and monitored. The time period for pumping will be confirmed based on monitoring results and may be increased or decreased based on actual field conditions. Similar to the TMF, it has been assumed that runoff and toe seepage from the WRSAs will be collected in the collection ponds and directed to the open pit until filling is completed. Ponds M1, A3, and C1 will drain by gravity to the open pit with the remainder of the ponds pumped to the open pit. For collection ponds that need to be pumped to the open pit, discharge to the environment maybe considered earlier if water quality has been shown to consistently meet effluent criteria, or where an engineered wetland has been constructed and demonstrated to consistently meet effluent criteria. If water from one or more of the collection ponds consistently meets effluent water quality criteria during the filling operations, the pond will be breached and allowed to discharge directly to the environment and water quality will continue to be monitored. In the event that one or more of the collection ponds is allowed to discharge directly to the environment prior to the open pit filling, increased pumping rates from Kenogamisis would be considered in order to maintain the pit lake filling timeline. The pit lake will be filled to allow development of a stratified pit lake with meromictic conditions. Anoxic conditions within the lower portion of the pit lake will be developed to promote sulfate reduction and formation of metal sulfides, which will co-precipitate arsenic and antimony, in the lower portion of the pit lake. This may require the addition of nutrients to create aquatic growth and provide a carbon source to stimulate the use of oxygen and development of anoxic conditions in the lower portion of the lake. The final water level of the pit lake will be approximately m amsl, which is 0.5 m higher than the recorded peak water level in Kenogamisis (between December 2006 and June 2015). This elevation difference will provide a gentle gradient to allow water to flow from the pit lake through a channel that will be constructed from the southeastern portion of the main open pit to the Southwest Arm of Kenogamisis (Figure 6-4). 6.2

40 \\cd1220-f02\01609\active\ \drawing\graphics\corel\closure_plan\ _fig_6_1_watermanagementplan_active_closure.cdr From Catchment Fresh Water Evaporation Precipitation Evaporation Seepage WRSAs Groundwater Recharge Mill Precipitation Evaporation Slurry Reclaimed Water Open Pit Sedimentation Mill Yard Precipitation Pond Evaporation Stormwater Runoff Runoff TMF Barton Precipitation Bay Ponds A1, A2, A3, C1, C2, D1, & D2 Runoff Underground Mill Losses Workings Evaporation Precipitation Evaporation Evaporation Equalization Pond M1 Pond Water Runoff in Ore Polishing Pond Precipitation Former Runoff Process Area Waste Rock Storage Area Reclaim Evaporation Dewatering Precipitation Groundwater Recharge Effluent Discharge Central Basin Evaporation Open Pit Evaporation South West Arm Runoff Precipitation Evaporation Sedimentation Pond Tailings Facility Effluent Treatment Plant Dam Seepage GW Seepage Precipitation To Outlet Basin From Catchment Locked in Water Dam Southwest Seepage Arm of Kenogamisis Client/Project December Greenstone Gold Mines GP Inc (GGM) Hardrock Project Figure No. 6-1 Title Water Management - Active Closure (Closure Years 1-5)

41 \\cd1220-f02\01609\active\ \drawing\graphics\corel\closure_plan\ _fig_6_2_watermanagementplan_ongoingpitfilling.cdr From Catchment Evaporation Precipitation Evaporation Seepage Fresh Water WRSAs Groundwater Recharge Mill Precipitation Evaporation Slurry Reclaimed Water Open Pit Sedimentation Mill Yard Precipitation Pond Evaporation Stormwater Runoff Runoff TMF Barton Precipitation Bay Ponds A1, A2, A3, C1, C2, D1, & D2 Runoff Underground Mill Losses Workings Evaporation Precipitation Evaporation Evaporation Equalization Pond Pond M1 Water Runoff in Ore Polishing Pond Precipitation Former Runoff Process Area Waste Rock Storage Area Evaporation Dewatering Precipitation Groundwater Recharge Effluent Discharge Central Basin Evaporation Open Pit Evaporation South West Arm Runoff Precipitation Evaporation Sedimentation Pond Tailings Facility Effluent Effluent Treatment Plant Dam Seepage To Outlet Basin GW Seepage Precipitation From Catchment Locked in Water Southwest Arm of Kenogamisis Dam Seepage Client/Project December Greenstone Gold Mines GP Inc (GGM) Hardrock Project Figure No. 6-2 Title Water Management Ongoing Pit Filling (Mine Years 6-56)

42 \\cd1220-f02\01609\active\ \drawing\graphics\corel\closure_plan\ _fig_6_3_watermanagementplan_afterpitfiling.cdr From Catchment Fresh Water Evaporation Precipitation Evaporation WRSAs Groundwater Recharge Sedimentation Pond Precipitation Evaporation Evaporation Precipitation Former Ponds A1, A2, A3, C1, Equalization C2, D1, & D2 Pond Former Pond M1 Mill Slurry Precipitation Reclaimed Evaporation Water Effluent Open Pit Effluent Runoff TMF Precipitation Barton Bay Mill Yard Stormwater Precipitation Evaporation Mill Losses Underground Workings Evaporation Water in Ore Runoff Former Process Area Waste Rock Storage Area Evaporation Polishing Pond Dewatering Precipitation Groundwater Effluent Recharge Discharge Central Basin Evaporation Open Pit Evaporation South West Effluent Arm Runoff Sedimentation Precipitation Evaporation Pond Tailings Facility Former Effluent Treatment GW Plant Seepage Precipitation To Outlet Basin From Catchment Locked in Water Dam Seepage Southwest Arm of Kenogamisis Client/Project December Greenstone Gold Mines GP Inc (GGM) Hardrock Project Figure No. 6-3 Title Water Management After Pit Filling (Mine Years 56+)

43 Rehabilitation Measures Final Closure In the long term, the annual discharge rate from the pit lake is estimated to range from 26,700 m 3 /month (37.0 m 3 /hr) to 171,900 m 3 /month (238.7 m 3 /hr) under climatic normal conditions. Predicted water quality from the epilimnion of the pit lake at time of discharge is presented in T. At the time of discharge cobalt is predicted to be above the PWQO with arsenic, antimony and uranium above the Interim PWQO. As discharge occurs, concentrations gradually decrease over time and will meet background or PWQO values within a very small mixing zone. Table 6-1: Pit Water Quality at Time of Discharge Parameter MMER O.Reg. 560/94 PWQO Pit Discharge - Interim Average Max Cl Chlorine Fl Flouroine SO4 2- Sulfate ,608 63,021 Total CN - Cyanide Total CN - WAD Cyanide WAD CN - Free Cyanide Free NH3 Total Ammonia Total NH3 +NH4 + Ammonia Un-ionized NO2 - Nitrite NO3 - Nitrate Hg Mercury Ag Silver Al Aluminum As Arsenic Be Beryllium B Boron Ca Calcium ,923 25,083 Cd Cadmium Co Cobalt Cr Chromium Cu Copper Fe Iron K Potassium ,362 2,376 Mg Magnesium ,940 8,998 Mo Molybdenum Na Sodium ,223 1,230 Ni Nickel

44 Rehabilitation Measures Final Closure Table 6-1: Pit Water Quality at Time of Discharge Parameter MMER O.Reg. 560/94 PWQO Pit Discharge - Interim Average Max P Phosphorous Pb Lead Sb Antimony Se Selenium Si Silicon ,260 1,268 Tl Thallium W Tungsten U Uranium V Vanadium Zn Zinc TDS Total Dissolved Solids , , Historical Underground Openings As required by O. Reg. 240/00, access to mine openings at surface shall be prevented. The location of all current known mine hazards (shafts, raises and open stopes) are shown on Figure 3-1 and the status of the cap at each location is presented in Table 6-2. As indicated in Section 4.0, a number of mine hazards have been identified in historical reports, but have not been located. After the start of the drawdown of the underground workings, an investigation should be carried out to identify any known mine hazards that have yet to be located. Table 6-2: Closure Status of Mine Openings Mine Opening ID Year Installed Existing Cap Details O. Reg 240/00 Compliant ** Located within footprint of open pit Mosher #1 Shaft 1998 Yes No Mosher #2 Shaft Collar None. Collar was filled to surface. Yes McLeod #1 Shaft 1996 Yes McLeod #2 Shaft 1996 Yes Yes McLeod #115 Raise 1996 Yes McLeod East Fan Raise 1996 Yes McLeod West Fan Raise 1998 Yes Yes McLeod #103 Raise Reported to be filled to surface Yes McLeod #2 Crusher Raise Unknown Yes McLeod #150 Waste Pass Unknown Yes Glory Hole None Yes 6.10

45 Rehabilitation Measures Final Closure Table 6-2: Closure Status of Mine Openings Mine Opening ID Year Installed Existing Cap Details O. Reg 240/00 Compliant ** Located within footprint of open pit Hardrock Stope Reported to be backfilled with waste rock Yes Hardrock Raise #1 Unknown Yes Hardrock Raise #2 Unknown Yes Hardrock Raise #3 Reported to be backfilled with waste rock Yes Hardrock Raise #4 Reported to be backfilled with waste rock Yes Hardrock Raise #5 Reported to be backfilled with waste rock Yes Hardrock Raise #6 Reported to be backfilled with waste rock Yes Hardrock Raise #7 Reported to be backfilled with waste rock Yes Hardrock Raise #8 Unknown Yes Hardrock Raise #9 Unknown Yes Hardrock Raise # Yes Hardrock Dewatering #1 Raise not yet constructed No Hardrock Dewatering #2 Raise not yet constructed No ** Was deemed to be compliant with O. Reg 240/00 at the time of last assessment. As indicated above, each of the mine openings in the PDA, with the exception of the Mosher No. 1 Shaft and the dewatering raises for this Project, fall within the footprint of the open pit. As the ground surface at the remaining openings will be mined and reside within the boundaries of the open pit, these structures will be secured from access by virtue of the rehabilitation measures for the open pit. No further closure work related to these openings is expected. All other remaining mine openings will be stabilized and secured as part of the closure works, in accordance with O. Reg. 240/ Stability of Subsurface Workings The primary intent of rehabilitation and closure of the underground workings is to achieve a physically safe and chemically stable environment. Prior to flooding the underground workings, the crown pillars are to be assessed, stabilized if necessary, and the long term stability certified by a Qualified Professional Engineer in accordance with O. Reg. 240/ TAILINGS MANAGEMENT FACILITY As required by O. Reg. 240/00, tailings management facilities shall be rehabilitated or treated to ensure permanent physical stability and effluent quality. The following describes how the TMF is to be rehabilitated to meet the requirements of O. Reg. 240/

46 Rehabilitation Measures Final Closure Dam Safety and Operation During the first five years of closure works, or until such time that the surface water at the TMF meets effluent water quality and is allowed to discharge passively to the environment, the TMF will be operated as set out in the TMF s Operations, Maintenance and Surveillance (OMS) manual. In the context of CDA s Mining Dams Bulletin (CDA 2014), the TMF can be considered to be in a state of closure under passive care once: the supernatant pond has been drained; the surface of the TMF is passively discharging to the environment; it has been shown that the TMF is stable; and the phreatic surface has come to a naturalized level with the environment. In accordance with the Canadian Dam Association (CDA) dam safety guidelines (CDA, 2013), with particular attention to the 2014 Mining Dams technical bulletin (CDA, 2014), a tailings facility that is under passive care will continue to require regular dam safety inspections, review, and maintenance as required Slope Stabilization At closure, a slope stability assessment is to be carried out for the TMF embankments. If required, the slopes will be stabilized (regraded or buttressed) to increase the factor of safety such that it meets the requirements set out by the CDA guidelines (CDA, 2013) Vegetative Cover The top surface of the tailings facility will be covered by a store and release cover. The store and release cover will be revegetated, which will promote evapotranspiration, reduce infiltration through the tailings, and prevent runoff from coming into contact with the tailings surface. This will improve surface water quality, reduce the potential for dust and surface erosion, and improve the aesthetics of the tailings impoundment. As the TMF will undergo progressive rehabilitation during operations, the design and performance criteria for the final cover over the south cell will be confirmed based on the results of the north cell rehabilitation and water quality monitoring. The TMF embankments will not require a vegetative cover as they are to be constructed of waste rock, which has very low susceptibility to dust and surface erosion. Further, the establishment of a vegetative cover over the waste rock embankments would be difficult due to the steep grades, coarse grained and very well drained nature of the material. 6.12

47 Rehabilitation Measures Final Closure Drainage Channels and spillways will be constructed to convey runoff from the north and south cells to the realigned Goldfield Creek tributary once water quality meets acceptable discharge criteria. Rehabilitation will include the construction of an overflow spillway between the supernatant pond in the north and south cells and depending on water quality either both cells will discharge, or water from the north cell will be directed to the south cell and a final discharge spillway created. Ditches and channels maybe constructed at each of the TMF cells to enhance runoff from the top of the tailings facility. These drainage features will further help to reduce infiltration volumes, and thereby reduce groundwater recharge through the tailings, effectively reducing loadings to the environment. The TMF decant structures will be will be decommissioned by sealing the horizontal conduit with concrete. By virtue of constructing a vegetated store and release cover over the tailings surface and draining the supernatant pond, it is expected that both surface water and seepage water quality from the TMF will improve. Seepage collection facilities at the TMF will continue operating in closure until such time that the water quality meets effluent water quality criteria. The seepage collection facilities will then be decommissioned by removing all pumps and piping, removal of impacted sediment from the ponds, breaching any berms, and directing flow to natural drainage channels as follows: Pond T1 will be directed to the remaining portion of Goldfield Creek, which reports to the Southwest Arm of Kenogamisis ; Pond T2 will discharge to the realigned tributary of Goldfield Creek, which reports to the Southwest Arm of Kenogamisis via Goldfield Creek; and Pond T3 will be directed to Watercourse M, which reports to the Southwest Arm of Kenogamisis. Within five years of the cessation of operations, water quality in the TMF ponds is predicted to improve substantially with cobalt and copper being the only parameters predicted to be slightly above the PWQO, and arsenic and aluminum above the Interim PWQO. Average monthly discharge rates from the TMF to the realigned tributary for normal climatic conditions range from 0 m 3 /month to 144,700 m 3 /month (201 m 3 /hr), with final discharge criteria to be developed as part of the realigned tributary design. This may require some storage and retention of peak flows and controlled discharge from the TMF. The discharge strategy from the TMF will consider effluent flows and water quality from the TMF, and the assimilative capacity of the realigned tributary of Goldfield Creek. The exact timing for the discharge of water to the environment will be confirmed based on water quality monitoring and regulatory requirements in accordance with O. Reg. 240/00 and the site s Environmental Compliance Approval from the MOECC. 6.13

48 Rehabilitation Measures Final Closure 6.3 WASTE ROCK STORAGE AREAS As required by O. Reg. 240/00, all waste rock piles shall be rehabilitated to meet physical stability and effluent quality criteria. As outlined in Sections 5.2 and 5.3, the WRSAs will be progressively rehabilitated during operations with only WRSA D remaining to be rehabilitated at the end of operations. Details related to the rehabilitation of the WRSAs are provided in Section 5.2. At closure, a store and release cover will be constructed over WRSA D and vegetated, similar to that described in Section 5.2. The revegetation targets are for approximately 40% coverage of the waste rock piles with the focus being placed on the plateaus and benches, allowing natural revegetation of the slopes. After the end of operations, runoff and toe seepage will continue to be collected by the perimeter ditches and directed to the collection ponds. During the open pit filling operations, water will be directed from the collection ponds as follows: Where gravity drainage from the collection ponds to the open pit is feasible (i.e. Ponds M1, C1, and A3), the ponds will be breached and replaced by drainage channels to convey flows directly to the open pit. Excess water in the other collection ponds (where gravity drainage to the open pit is not feasible) will be pumped to open pit. If water from one or more of the collection ponds is shown to consistently meet effluent water quality criteria during the filling operations, the pond will be breached and allowed to discharge directly to the environment and water quality will continue to be monitored. Based on water quality predictions, the density of the water from the collection ponds will be significantly more dense than the water pumped to the surface of the pit from Kenogamisis, allowing for the development of a permanent stratification (meromictic lake) of the pit lake (Stantec 2015e and 2016h). Once the open pit has filled, only collections ponds that drain by gravity will continue to discharge to the pit lake. Assuming water quality is acceptable for discharge, collection ponds that required pumping to the open pit during filling, will be either discharged directly to the environment and monitored, or, if required, treated through an engineered wetland prior to discharge. In the event that an engineered wetland is required, water will continue to be pumped to the open pit until water quality from the engineered wetland has been shown to consistently meet effluent criteria. To support the design of the engineered wetland systems, pilot scale treatment studies will be carried out during operations to evaluate the treatment efficiencies and better define the systems to be used at closure. 6.14

49 Rehabilitation Measures Final Closure 6.4 OVERBURDEN STOCKPILES At closure, stockpiled overburden and topsoil will be used for rehabilitation of the various Project components. For the overburden placed over the MacLeod historical tailings, a minimum thickness of 1.0 m will be maintained during closure to maintain the operational cover performance and reduce infiltration into the historical tailings. 6.5 REMOVABLE INFRASTRUCTURE, EQUIPMENT, AND MATERIALS At the end of the mine life, all infrastructure, equipment and mining materials are to be removed from the site, or in some cases rendered unusable. This includes buildings, pipelines, borrow areas, site lighting and security, service water supply, water management facilities, petroleum products, and waste materials in accordance with applicable regulations including O. Reg. 240/00. The majority of these works will be carried out within the first five years of closure; however, some facilities (i.e., access roads and the effluent treatment plant) may be required for the proper care and maintenance of the site during closure. Facilities will be removed/rehabilitated when they are no longer required during closure. All infrastructure will be decommissioned in accordance with O. Reg. 240/00 or other applicable legislation. Once removed, the sites will be stabilized to minimize erosion and revegetated as required. 6.6 REVEGETATION The objectives of revegetation program are to stabilize surface materials from wind and water erosion, improve aesthetics, and establish self-sustainable vegetation growth. Revegetation will occur as soon as practical after mine components are no longer needed. In preparation for revegetation efforts, the ground surface is to be prepared. This may include scarification or ripping of compact surfaces, contouring the ground surface to match surrounding topography, and making soil amendments to support vegetative growth, and implementing erosion protection measures to protect the soil cover until vegetative is established. The requirements for the site preparation for revegetation will meet GGM s land use objectives and O. Reg. 240/00. Details of the seed mixture, mulching and fertilization requirements will be confirmed through a test plotting program that is to be carried out in advance of closure. The selected seed mixture will be comprised of non-invasive species to promote the development of natural revegetation. 6.15

50 Rehabilitation Measures Final Closure 6.7 EFFLUENT WATER QUALITY CONTINGENCY MEASURES The water quality from the WRSAs, TMF, and pit lake have been estimated using a site-wide water balance and water quality model (Stantec 2016g). The modelling approach has incorporated conservative assumes to support the assessment of potential effects for the Environmental Assessment. It is expected that long term effluent water quality from the Project will stabilize and parameter loadings are predicted to decrease with time and eventually meet acceptable discharge criteria. However, in the event that water requires further treatment, engineered wetland treatment options will be evaluated Wetland Treatment Throughout the open pit refilling, water quality from the TMF, WRSA, and open pit will be monitored and water quality predictions will be periodically revised. If required, an engineered wetland system could be implemented for effluent streams that do not meet effluent water quality criteria. To support the design of an engineered wetland system, pilot scale treatment studies will be carried out during operations to evaluate the treatment efficiencies and better define the systems to be used at closure. While it is expected that ongoing monitoring and adaptive management can mitigate treatment requirements, these treatability studies will be completed as a contingency measure. 6.8 SCHEDULE A conceptual level closure schedule for the Hardrock Project is presented in Figure 6-4. The key dates, in terms of Years after closure, include: Year 1 End of mining and processing operations and start of rehabilitation measures Year 5 Pumping from TMF expected to no longer be required; Year 56 Pit refilling complete to 331 m amsl; and Year 58 Effluent water quality from entire site shown to meet closure criteria. 6.16

51 Rehabilitation Measures Final Closure Figure 6-4: Final Closure Schedule Closure Year >60 Construction, Mining, Processing Main Open Pit Satellite Open Pit Process Plant and Infrastructure Ore Stockpiles Low Grade Medium and High Grade Waste Rock WRSA_A WRSA_A_Tailings WRSA_A_Extension WRSA_B WRSA_C WRSA_CC WRSA D In Pit Dumping Tailings North Cell South Cell Infilled during operations Rehabilitated during operations Closed during operations Closed during operations Closed during operations Closed during operations Closed during operations Closed during operations Finished during operations Closed during operations Legend Active Closure / Rehabilitation Work Monitoring / Maintenance 6.17