business case study water management...

December 27, 2011

RENARD PROJECT

Business Case Study Water Management Plan

REPO

RT

Project Number:Document Number:

10-1427-0020/3091 Doc. No. 074 Rev. 0

Distribution:

3 Copies: Les Diamants Stornoway (Canada) Inc. 1 Copy: Golder Associés Ltée (Montreal) 2 Copies: Golder Associates Ltd. (Burnaby)

Submitted to:Les Diamants Stornoway (Canada) Inc. 1111 St. Charles Ouest Bureau 400 Longueil, Québec J4K 5G4 Attention: Mr. Robert Beaulieu

BUSINESS CASE STUDY WATER MANAGEMENT PLAN

December 27, 2011 Project No. 10-1427-0020/3091 Document No. 074 Rev. 0 i

Executive Summary

Les Diamants Stornoway (Canada) Inc. (Stornoway) is currently evaluating the feasibility of developing the Renard Project as a diamond mine on the Foxtrot Property, located in the James Bay region of north central Québec. The Renard Project site is located next to Lagopède Lake, at longitude 72°11’ West and latitude 52°49’ North in the Otish Mountains, 820 km north of Montréal and 360 km north-northeast of Chibougamau. The site area is part of the Eastmain River watershed.

The project extends over 19 years of mining (July 2015 to June 2033), preceded by two years of construction and site development. During this period, 44.9 M tonnes of ore from five kimberlite pipes (R2, R3, R4, R9 and R65) are planned to be mined by open pit and/or underground methods.

This report presents the Renard Project water management plan and water balance as part of the project’s business case study. Details on the design of the water treatment facilities (by Golder Associate Ltd.), as well as on potable water supply and sewage treatment for mine site facilities (by SNC-Lavalin Inc.), are presented under separate covers.

The water management objectives for the project are to reduce potential impacts to the quantity and quality of surface water and groundwater resources at the site. Diversion ditches will be constructed to divert clean runoff water away from areas affected by the mine or mining activities. Contact water originating from affected areas will be intercepted, collected, and conveyed to central storage facilities for re-use in process, or treated as required prior to release to Lake Lagopède. The uncontrolled release of contact water to neighbouring lakes is not anticipated.

As a general rule, 100-year return period events apply to the design of perimeter infrastructure operating during both the construction and mine operations phases. Ten-year return period events apply to the design of internal infrastructure or to infrastructure operating during the construction phase only.

The mine site is concentrated on an area of 2.5 km2 draining towards Lagopède Lake. Two main perimeter ditches will be used to collect the contact runoff from most of the mine site and convey it to a central R65 sump for monitoring and treatment (if necessary) prior to release to Lagopède Lake. A separate sedimentation pond will receive surface runoff from the mine camp located to the south of the main mine site. Water collected within the sedimentation pond will be monitored and treated as required prior to release to Lagopède Lake.

Groundwater inflows to the R2, R3 and R65 pits and in the underground developments (R2, R3, R4, R9, shaft, and ramp) were considered based on an existing hydrogeological study. The inflows are assumed to drain to intermediate collection points where pump stations will be located to pump the water to the mill as process water, with any excess sent to the R65 sump for monitoring and treatment (if required). It is estimated that process water demand can be satisfied completely by groundwater inflows reporting to the pits and underground.

Following the completion of mining, the open pits will gradually flood through groundwater inflow, direct precipitation, and surface water runoff. The pit lake water quality will be monitored and any excess water will be treated, if required, prior to discharge to Lagopède Lake.


December 27, 2011 Project No. 10-1427-0020/3091 Document No. 074 Rev. 0 ii

Water management during closure and reclamation will involve maintaining some surface water diversions to prevent clean runoff water from coming into contact with areas affected by the mine or mining activities. The water management facilities, including the water collection systems (ditches and sumps), and treatment plants will be required to remain in place until mine closure activities are complete and monitoring results demonstrate that contact water quality conditions are acceptable for discharge to the environment without further treatment.

Once contact water quality conditions fulfill the acceptable discharge standards (Direction 019, MDDEP 2005), original drainage patterns to natural creeks and lakes around the site will be re-established to the extent practicable. All infrastructure that were maintained for mine operations, closure, and/or reclamation phases, including ditches and sumps, will be re-contoured and/or surface treated according to site-specific conditions to minimize windblown dust and erosion from surface runoff, and enhance the development site area for revegetation and wildlife habitat.


December 27, 2011 Project No. 10-1427-0020/3091 Document No. 074 Rev. 0 iii

Table of Contents

EXECUTIVE SUMMARY ............................................................................................................................................................ i

1.0 INTRODUCTION ............................................................................................................................................................... 1

2.0 CLIMATE AND HYDROLOGY ......................................................................................................................................... 3

3.0 WATER MANAGEMENT PLAN: OBJECTIVE AND STRATEGY .................................................................................... 6

4.0 WATER MANAGEMENT PLAN CRITERIA ..................................................................................................................... 7

5.0 MINE DEVELOPMENT AND MILL PROCESSES ............................................................................................................ 9

6.0 CONCEPTUAL WATER MANAGEMENT PLAN ........................................................................................................... 11

6.1 Construction Phase ........................................................................................................................................... 11

6.2 Operations Phase .............................................................................................................................................. 12

6.3 Closure and Post-Closure Phases ..................................................................................................................... 14

7.0 GROUNDWATER INFLOW ............................................................................................................................................ 15

8.0 WATER MANAGEMENT INFRASTRUCTURE .............................................................................................................. 16

8.1 Ditches ............................................................................................................................................................... 16

8.2 Culverts ............................................................................................................................................................. 16

8.3 Collection Sumps and Sedimentation Ponds ..................................................................................................... 21

8.4 Pumping Stations ............................................................................................................................................... 22

8.5 Treatment Plants ............................................................................................................................................... 23

9.0 MINE SITE WATER BALANCE ...................................................................................................................................... 24

9.1 Model Development ........................................................................................................................................... 24

9.2 Model Results .................................................................................................................................................... 25

10.0 RECOMMENDATIONS ................................................................................................................................................... 28

11.0 REFERENCES ................................................................................................................................................................ 30

12.0 CLOSURE ....................................................................................................................................................................... 29


December 27, 2011 Project No. 10-1427-0020/3091 Document No. 074 Rev. 0 iv

TABLES Table 1: Multi-Annual Monthly Means for Main Climatic Variables (from Golder, 2011) ............................................................ 3

Table 2: Frequency Analysis for Extreme Sub-Daily Rainfall Events (from Golder, 2011) ......................................................... 4

Table 3: Average Runoff for Different Land Types on the Project Site (from Golder, 2011) ....................................................... 5

Table 4: Design Criteria for Water Management Infrastructure .................................................................................................. 7

Table 5: Mine Development Sequence (based on Stornoway, 2011) ........................................................................................ 9

Table 6: Mill Process Variables at Design Capacity (based on AMEC, 2011) .......................................................................... 10

Table 7: Mining Schedule and Production Rates (based on Stornoway, 2011 and AMEC, 2011) ........................................... 10

Table 8: Surface Catchment Areas Throughout Life-of-Mine According to Collection Point .................................................... 13

Table 9: Surface Catchment Areas Throughout Life-of-Mine According to Land Type ............................................................ 13

Table 10: Proposed Ditches - Characterization ........................................................................................................................ 17

Table 11: Proposed Ditches - Estimation of Quantities (3, 4)...................................................................................................... 19

Table 12: Proposed Culverts .................................................................................................................................................... 20

Table 13: Proposed Pumping Stations ..................................................................................................................................... 23

Table 14: Proposed Treatment Stations ................................................................................................................................... 23

Table 15: Modelled Water Flows for the Construction and Operations Phases ....................................................................... 26

Table 16: Water Balance Results for the Mill (Process Flows) ................................................................................................. 26

Table 17: Water Balance Results for the Shaft, Ramp, Pit, and Underground Works Drainage .............................................. 27

Table 18: Water Balance Results for the R65 Treatment Plant (P17) ...................................................................................... 27

FIGURES Figure 1: Renard Site Location ................................................................................................................................................... 2

Figure 2: Estimated Groundwater Inflow to the Pits and the Underground Developments (based on ITASCA, 2011) ............. 15

Figure 3: Modelled R65 Treatment Rates throughout Life-of-Mine .......................................................................................... 25

Figure 4: Modelled Total Groundwater Inflow to the Pits Compared to Process Water Demand ............................................. 25


December 27, 2011 Project No. 10-1427-0020/3091 Document No. 074 Rev. 0 v

APPENDICES APPENDIX A Site Plan and Mining Schedule

APPENDIX B Conceptual Water Management Plans

APPENDIX C Flow Logic Diagrams

APPENDIX D Water Management Infrastructure

APPENDIX E Mine Water Balance


December 27, 2011 Project No. 10-1427-0020/3091 Document No. 074 Rev. 0 1

1.0 INTRODUCTION Les Diamants Stornoway (Canada) Inc. (Stornoway) is currently evaluating the feasibility of developing the Renard Project as a diamond mine on the Foxtrot Property, located in the James Bay region of north central Québec. The Renard site is located next to Lagopède Lake, at longitude 72°11’ West and latitude 52°49’ North in the Otish Mountains, 820 km north of Montréal and 360 km north-northeast of Chibougamau. The site area is part of the Eastmain River catchment. Figure 1 below presents the general site location.

The project extends over 19 years of mining (July 2015 to June 2033), preceded by two years of construction and site development. During this period, 44.9 M tonnes of ore from five kimberlite pipes (R2, R3, R4, R9, and R65) are planned to be mined by open pit and/or underground methods.

This report presents the Renard Project water management plan and water balance as part of the project’s business case study. Details on the design of the water treatment facilities (by Golder Associates Ltd.), as well as on potable water supply and sewage treatment for mine site facilities (by SNC-Lavalin Inc.), are presented under separate covers.



Figure 1: Renard Site Location



2.0 CLIMATE AND HYDROLOGY The Renard Project site is located within the sub-arctic region of Canada. This region is characterized by winters lasting from October to April with average monthly temperatures around or below -20°C from December to February. Due to the absence of local climatic and hydrologic data, available regional data compiled in (Roche, 2010), (Golder, 2011) and (SNC-Lavalin, 2011a) were used to estimate the variables required for the preparation of this water management plan.

The regional climatic stations used for the analysis are located within a radius of 300 km of the mine site. The closest station, Nitchequon (Environment Canada ID 7095480), which is located 97 km from the site, has a 43 year period of record spanning 1942 to 1985. Despite the relative age of its records, the Nitchequon station is considered the best available source of information for estimating site climate conditions. Data from the Bonnard, La Grande Rivière A, and La Grande IV A regional stations were also used in the analysis, either directly or for comparative purposes, and to identify regional trends.

Table 1 presents the estimated multi-annual monthly means for site temperature, total precipitation, snow cover, and lake evaporation. With an annual average temperature of -4.2°C, the annual lake evaporation is limited to 319 mm distributed over a four- to five-month ice-free season. The annual mean total precipitation is 798 mm. Statistics of multi-annual records suggest a typical annual total precipitation between 434 mm (1:100 year dry year) and 1099 mm (1:100 year wet year). The average monthly snow cover reaches a maximum of 82 cm in March. Daily maximum can be as high as 104 cm for an average year, or 171 cm during a 1:100 year daily snowfall event.

Table 1: Multi-Annual Monthly Means for Main Climatic Variables (from Golder, 2011)

Month Temperature (°C) Precipitation

(mm) Snowcover (cm snow)

Lake Evaporation

(mm)

(Annual average) -4.2 798 n/a 319 January -23.5 38 56 0 February -21.8 32 71 0 March -15.1 39 82 0 April -6.2 39 71 0 May 1.8 58 21 0 June 9.7 89 0 96 July 13.6 107 0 94 August 12.0 111 0 77 September 6.5 100 0 52 October 0.0 81 3 0 November -8.0 61 17 0 December -19.3 44 39 0



Table 2 presents the extreme sub-daily rainfall events for the region, as determined by Environment Canada from the Nitchequon record and extrapolated by Golder for the 1:1,000 year events (Golder, 2011). Twenty-four hour extreme rainfall varies between 36 mm and 97 mm for return periods between 2 and 1,000 years, respectively.

Table 2: Frequency Analysis for Extreme Sub-Daily Rainfall Events (from Golder, 2011) Return Period

(years) Rainfall Depth (mm) Function of the Event Duration

5 min 10 min 15 min 30 min 1 hr 2 hrs 6 hrs 12 hrs 24 hrs 2 5 6 7 10 12 17 24 29 36 5 7 9 11 14 17 21 30 36 47 10 9 11 13 16 20 23 34 41 54 25 11 13 15 20 24 26 39 47 63 50 13 15 17 22 27 29 42 51 69 100 14 16 19 24 29 31 46 55 76

1,000 20 22 25 33 38 39 58 69 97

The predominant wind directions are from west (11.7% of the time) and south (8.8% of the time) (Roche, 2010). The average wind velocities vary between 12.8 km/h (northeast) and 19.4 km/h (west-northwest).

The expected maximum annual ice cover thickness averages 95 cm, with variations between 42 cm to 119 cm from year to year (Golder, 2011). The lakes have permanent ice cover typically between the end of October and the end of May.

Data from regional river discharge gauging stations were used to obtain estimates of terrestrial runoff for small natural catchments on the project site (Golder, 2011). The estimates were then adjusted based on the anticipated hydrologic characteristics of mine site land types to obtain the estimated runoff under average annual precipitation conditions presented in Table 3. The methodology and the data are considered to be suitable for the feasibility level design.

It is noted that a local river discharge survey was underway at the time of preparation of this report (Roche, 2011). During the detail engineering phase, it is recommended to review the results of the survey and, if appropriate, to use them to update the runoff estimations presented in Table 3.



Table 3: Average Runoff for Different Land Types on the Project Site (from Golder, 2011)

Month

Total Runoff For Average Annual Precipitation Conditions

Natural Areas

Pkc Facility, Overburden Stockpile, Disturbed Natural

Land

Waste Rock Storage Facility, Pre-Operation

Ore Stockpile Open Pits, Built

Areas

mm mm mm mm January 0 0 0 0 February 0 0 0 0 March 0 0 0 0 April 0 0 0 0 May 229 248 242 254 June 34 60 52 68 July 54 79 71 87 August 55 82 73 90 September 49 74 66 81 October 45 53 50 55 November 0 0 0 0 December 0 0 0 0 (Annual sum) 467 595 554 636



3.0 WATER MANAGEMENT PLAN: OBJECTIVE AND STRATEGY The strategy for water management on site is to reduce the potential impact of the Renard Project on local and regional water resources while satisfying process water requirements. The two primary objectives of the water management strategy are to manage all contact water in an efficient and effective manner, and to reduce the amount of contact water that will require treatment prior to discharge to the environment.

The approaches that will be used to achieve these objectives include:

Implementing measures (i.e., clean water diversions) to avoid the contact of clean runoff water with areas affected by the mine or mining activities;

Collecting, transporting, and treating as necessary, mine water, and runoff water in contact with core project activities;

Reducing the intake of fresh water from the environment by recycling and reusing water to the greatest extent possible;

Monitoring quality of discharge; and

Adjusting management practices if monitoring results indicate discharge quality does not meet discharge criteria.

For the purpose of the water management strategy, surface water has been grouped into two categories: contact water and non-contact water. Contact water is defined as any water that may have affected by mining activities. Contact water includes:

Surface runoff from the mining and milling areas;

Groundwater inflows to mine workings;

Surface runoff (and shallow drainage) from rock, overburden and processed kimberlite disposal areas;

Processed kimberlite transport water;

Seepage water through the rock, overburden and processed kimberlite containment areas; and

Dewatering volumes having high total suspended solids (TSS) concentrations.

All contact water will be intercepted, contained, re-used to the extent practical, monitored, and if required, treated prior to discharge to the receiving environment.

Non-contact water originates from areas unaffected by mining activity, and does not come into contact with developed areas. It is limited to intercepted and diverted runoff originating from areas undisturbed by mining.



4.0 WATER MANAGEMENT PLAN CRITERIA Table 4 lists the criteria used for the design of runoff collection ditches, sumps and sedimentation ponds under this water management plan. As a general rule, 100-year return period design events apply to perimeter infrastructure operating during both the construction and mine operations phases. Ten-year return period events apply to the design of internal infrastructure or to infrastructure operating during the construction phase only.

Table 4: Design Criteria for Water Management Infrastructure Aspect Component Design Criteria 1 Comments/Assumptions

Runoff Collection

Non-contact ditch and culvert capacity 1:100 year peak runoff event

Applies to “permanent” infrastructure operating during construction and operating phases. Temporary infrastructure operating during construction phase designed to the 10-year return period event.

Perimeter contact ditch and culvert capacity

1:100 year peak runoff event

Internal ditch and culvert capacity 1:10 year peak storm event

Contact water collection ditch with no chance of overflow outside of the construction or operating areas.

Ditch freeboard 0.30 m Runoff coefficient for ditch and culvert design

1.0 Based on steep, well-graded, non-vegetated areas with high antecedent moisture conditions.

Sump capacity 1:100 year 24-hour runoff event volume in addition to maximum operating storage volume under average year climate conditions

Sump freeboard 1.0 m

Sump pumping capacity

1:10 year, 24-hour runoff event volume within a one week period

Sedimentation pond (if required)

Sediment pond

1:100 year, 24-hour runoff event volume in addition to maximum operating storage volume under average year climate conditions

Water storage (sumps and sediment control ponds) will retain contact water for water quality monitoring and treatment, if required, prior to discharge to the natural receiving environment.

Sediment pond freeboard 1.0 m

Sediment pond pumping capacity

1:100 year, 24-hour runoff event volume within a one week period



Aspect Component Design Criteria 1 Comments/Assumptions

Water Quality

Sediment control at water storage

Directive 019 on the mining industry (MDDEP, 2005)

Sump water quality Not applicable

Quantity and quality of sump water discharged to retention ponds will be monitored. If required, water treatment will be implemented to ensure that water quality thresholds are met prior to discharge to the natural receiving environment.

Sediment pond water quality

TSS threshold of 15 mg/L (monthly average) and 30 mg/L (instantaneous maximum)

Effluent water quality

Applicable effluent discharge guideline values specified in Section 2.1 of the Directive 019 and in the objectives of environmental discharge (OED) according to the Québec “Loi sur la qualité de l’environnement” (LQE)

1) A runoff event is either the result of a rainfall storm during summer and fall, or the sum of rainfall and snowmelt during

the freshet period. The design of ditches, sumps and sediment retention ponds considered both types of events and their

associated runoff coefficients. The dimensions of the water infrastructure will be based on the type of event that produces the largest

peak and volume of water for the corresponding return period.



5.0 MINE DEVELOPMENT AND MILL PROCESSES The figure in Appendix A presents the site layout including the location and extent of all important site elements, including: the mill complex; camp; R2, R3 and R65 pits; underground shaft and ramp; waste rock, ore and overburden piles; and processed kimberlite containment (PKC) facility. Table 5 and Figures B1 to B3 (Appendix B), inclusive, present the development of the site between the beginning of construction in Year -2 (Phase 1; calendar year 2013) to the end of operations in Year 19 (Phase 3; calendar year 2033). A copy of the mining schedule provided by Stornoway is also provided in Appendix A.

Table 5: Mine Development Sequence (based on Stornoway, 2011)

Phase Operation Year Calendar

Year Area Development Sequence

1 -2 2013

Construction of the mine complex. Dewatering of the pond inside the R65 and R2 pits area. Construction of a diversion structure around the pond located inside the R65 pit/sump area. Start of operation for the first unit of the R65 water treatment plant. Delineation of the future R2/R3 open pit area. Development of the waste rock storage facility, and of the ore and overburden stockpiles. Ramp development. Beginning of shaft sinking. Construction of the R65 sump including ore extraction.

2 -1 2014

Beginning of R2/R3 overburden and waste extraction (open pit and underground). Beginning of R2/R3 ore extraction (open pit). Start of operation for the second water treatment unit at R65.

3

1 2015 Start of mill operation (July 2015). Development of the PKC facility. Beginning of ore extraction from R2 (underground).

3 2017 Resume ore-extraction at R65 (open pit). Beginning of ore extraction from R3 (underground). The R2/R3 pits are connected to the underground developments.

7 2021 Beginning of waste rock extraction from R4/R9 (underground). 11 2025 Beginning of ore extraction from R4/R9 (underground).

19 2033 End of ore mining. End of mill operations (June 2033).

The mill process water balance is a key input to the water balance analysis. It defines the transfer of water within the processed kimberlite (PK) and concentrate, the required process water make-up rates, as well as the minimum fresh water requirements for process. Table 6 summarizes the process water balance variables as provided by AMEC (2011) and Stornoway (2011). Thirty-six percent of the required process water demand is satisfied by the moisture content of the excavated ore. The remaining water demand is about 4.7 M m3 over the life-of-mine (Table 7).



Table 6: Mill Process Variables at Design Capacity (based on AMEC, 2011 and Stornoway, 2011) Property Value Comment/Assumptions

Operating rate 343 tonne/hr Ore mass not including water to mill.

Ore water feed rate 19.9 tonne/hr Water mass in addition to the ore mass. Corresponds to a 5.8% water content by total mass (water mass divided by total mass). Transfer of PK to PKC - solids 338 tonne/hr Mass not including water to PKC.

Transfer of PK to PKC - water 55.2 tonne/hr

Transfer of concentrate to PKC facility - solids 5.4 tonne/hr Mass not including water to PKC facility.

Transfer of concentrate to PKC facility - water 0.4 tonne/hr

Total process water demand in addition to ore water

35.7 tonne/hr Any combination of freshwater, reclaim pond, settling pond, etc., is acceptable.

Min. Freshwater make-up rate 0 m

3/hr Freshwater is not a required process water source.

Table 7: Mining Schedule and Production Rates (based on Stornoway, 2011 and AMEC, 2011)

Year of Operation

Ore to Mill

Ore Processing Rate - Design

Capacity Months of Operation

Mill Utilization

Rate

Ore Processing

Rate - Average Capacity

Number of Days of Mill Down-time

Total Process Water

Demand in Addition to Ore Water

k tonne tonne/hour % tonne/hour - k m3 1 (2015) 323 343 6 21% 73 145 34 2 (2016) 2,296 343 12 76% 261 87 239 3 (2017) 2,555 343 12 85% 292 55 266 4 (2018) 2,555 343 12 85% 292 55 266 5 (2019) 2,555 343 12 85% 292 55 266 6 (2020) 2,555 343 12 85% 291 56 266 7 (2021) 2,555 343 12 85% 292 55 266 8 (2022) 2,555 343 12 85% 292 55 266 9 (2023) 2,555 343 12 85% 292 55 266 10 (2024) 2,555 343 12 85% 291 56 266 11 (2025) 2,555 343 12 85% 292 55 266 12 (2026) 2,555 343 12 85% 292 55 266 13 (2027) 2,555 343 12 85% 292 55 266 14 (2028) 2,555 343 12 85% 291 56 266 15 (2029) 2,555 343 12 85% 292 55 266 16 (2030) 2,555 343 12 85% 292 55 266 17 (2031) 2,555 343 12 85% 292 55 266 18 (2032) 2,555 343 12 85% 291 56 266 19 (2033) 1,371 343 6 92% 316 15 143

Total 44,869 4,672



6.0 CONCEPTUAL WATER MANAGEMENT PLAN The plans in Appendix B present the proposed water management infrastructure required to fulfill the objectives established in Section 3 of this report. The flow logic diagrams in Appendix C schematically present the water management approach for critical years throughout the life-of-mine.

6.1 Construction Phase Starting from Year -2 (2013), the mine camp and mill complex will be built in parallel with the site road network. The early construction of the camp sedimentation pond (S18) and the use of the dewatered pond within the R65 footprint (S22) will provide two TSS treatment facilities on site during the construction phase. During the operations phase, the camp sedimentation pond will continue to collect runoff from the camp for TSS removal prior to discharge to Lagopède Lake.

To reduce the needs for storage, pumping and treatment during the construction phase, best management practices will be used where practicable to limit the total suspended solids in the runoff water. These practices will include, but may not be limited to, the following:

Silt fencing placed along the edges of all areas where soils are disturbed. Additional silt fences will be added as required where there is potential to mobilize fine-grained materials in surface water runoff as a result of construction activities;

Sediment barriers constructed of rip-rap and drain rock in drainage courses;

Waterbars (small features built diagonally across the road) used along construction access roads to minimize erosion of the road surface;

Stockpile protection for all temporary construction materials (cement, sand, etc.), either by plastic sheets for very small areas, or with surrounding silt fences for larger areas. Silt fences will also be used as required to improve the efficiency of the sedimentation ponds (see Figure D4 in Appendix D);

Rock sheets covering soils exposed for longer periods of time; and

The construction of small temporary and localized collection sumps, where required.

The first unit of the R65 water treatment plant (located near the R65 pit) is expected to be operational at the beginning of the construction phase. If required, the unit will be used to treat contact water prior to discharge to Lagopède Lake, including dewatering volumes from the existing lakes within the R2 and R65 footprints (30,650 m3 and 14,700 m3, respectively; Roche, 2011). The early installation of the first unit will also allow the treatment (if required) of the runoff from the waste rock/ore/overburden piles during Operation Year -2 (2013).



The R65 sump and second treatment plant unit are expected to be operational before the spring of Year -1 (2014). A short water diversion structure may be required to facilitate the construction of the R65 sump. The proposed strategy during the transition phase until the R65 treatment plant and sump are fully operational is to:

Manage the deposition of waste rock/ore/overburden to reduce the impacted surface area;

Manage the snow cover to reduce the volume of snow left on and around the waste rock/ore/overburden piles at the start of the freshet;

Build temporary ditches around the waste rock/ore/overburden piles;

Use best management practices to reduce potential TSS generation in surface water runoff; and

Build small localized collection sumps and, if required, pump the collected water to the camp sedimentation pond and/or to the temporary sedimentation pond.

6.2 Operations Phase The main basis of the proposed water management plan is to collect, monitor and treat (if required) all contact water from the site (with the exception of the camp) at the R65 sump and treatment unit (marked P17 on Figure B1 in Appendix B). After the required treatment, the water will be discharged to Lagopède Lake. Contact water from the camp will be treated at the S22 sedimentation pond prior to discharge to Lagopède Lake.

A ditch network will convey the surface water runoff to the R65 sump by gravity. A first main ditch, flowing alongside the southern edge of the site, and identified by reference points P8, P4, P3, P2 and P1 on Figure B3 in Appendix B, will collect the runoff from the southern part of the PKC facility, the eastern part of the waste rock storage facility, the overburden stockpile, the ore pile, and the plant site.

A second main ditch, identified by reference points P21, P10, P9 and P5 on Figure B3 in Appendix B, will collect the runoff along the northern edge of the site from the northern part of the PKC facility and the western part of the waste rock storage facility.

A diversion ditch (170 on Figure B2) is required west of the PKC facility and east of the R65 sump to prevent non-contact water from entering the site.

Once complete, the R2, R3, R4 and R9 underground developments will be inter-connected and drain to the lower point of the main shaft. A sump (P14 on the plans) at this location will collect water reporting to the main shaft, including groundwater inflows to the underground developments. From Year 3 (2017) onwards, P14 will also collect direct precipitation and groundwater inflows to the R2 and R3 pits. Water from the shaft sump will be pumped to the mill to satisfy the process water demand, with any excess sent to the R65 sump for monitoring and treatment (if required). A collection and pumping point (P15) will also be installed at the bottom of the ramp. Based on water balance results (see Section 9.0), it is anticipated that the groundwater inflows from the underground workings will fully satisfy process water demand.



Snow management will be an important part of the water management plan due to the relatively long winter season. Snow removal may be necessary from certain areas (e.g., roads, mill complex) to allow for mine operation. The following three areas have been identified for potential snow storage:

Northeast of the waste rock storage facility;

East of the pre-operation stockpile and southwest of the overburden stockpile; and

The area between the waste rock storage facility, the overburden stockpile, and the PKC facility.

To the extent practicable, the snow should be stored in the same catchment area from which it was removed in order to limit potential runoff surcharging to local drainage ditches. A detailed snow management guideline establishing the preferred approach to snow management and snow removal on site shall be prepared prior to site construction.

Tables 8 and 9 present catchment areas along the life of mine according to collection point and land use type, respectively.

Table 8: Surface Catchment Areas Throughout Life-of-Mine According to Collection Point Plan Reference

Points P18 P1, P2, P3, P4 R2, R3 P5, P9, P10 R65

Year of Operation

Calendar Year

Surface Water Catchment Areas (ha)

Camp and Sedimentatio

n Pond

Mine Complex, Southwestern and Eastern

Part of the Waste Rock Storage Facility, the

Overburden Stockpile, and the Southern Part of the

PKC Facility

R2 & R3 Pit Areas

Northwestern Part of the

Waste Rock Storage

Facility and the Northern Part of the

PKC Facility

R65 Pit

AreaTotal

-2 2013 4.5 119.4 16.2 12.3 21.5 173.8-1 2014 4.5 119.4 16.2 12.3 21.5 173.8

1-19 2015-2033 4.5 118.0 16.2 85.3 21.5 245.4

Table 9: Surface Catchment Areas Throughout Life-of-Mine According to Land Type Area (ha) by Land Type

Operation Year

Calendar Year Natural

PKC, Overburden,

Disturbed

Waste Rock,

Ore Pile Build, Pit Total (ha)

-2 2013 55.5 59.4 17.5 41.5 173.8 -1 2014 48.9 42.8 29.9 52.3 173.8 1 2015 59.1 102.0 29.9 54.4 245.4 2 2016 37.8 123.4 29.9 54.4 245.4

3-19 2017-2033 16.4 144.8 29.9 54.4 245.4



6.3 Closure and Post-Closure Phases The following principles are proposed for the closure and post-closure water management plan1:

Water management during closure and reclamation will involve maintaining surface water diversions to prevent clean runoff water from coming into contact with areas affected by the mine or mining activities. The water management facilities, including the water collection systems (ditches and sumps) and treatment plants, will be required to remain in place until mine closure activities are complete and monitoring results demonstrate that contact water quality is acceptable for discharge to the environment without further treatment.

Following completion of mining, groundwater inflow, direct precipitation, and surface water runoff will gradually flood the open pits. The estimated time required to flood the pits is presented under separate cover. The pit lake water quality will be monitored and any excess water will be treated, if required, prior to discharge to Lagopède Lake.

Once contact water quality conditions fulfill the acceptable discharge standards (Directive 019, MDDEP 2005), original discharge paths to natural creeks and lakes around the site will be re-established to the extent practicable. All infrastructure that were maintained for mine operations, closure and/or reclamation phases, including ditches and sumps, will be re-contoured and/or ground surfaces treated according to site-specific conditions to reduce windblown dust and erosion from surface runoff, and enhance the development site area for re-vegetation and wildlife habitat.

1 At the time of preparing this report, a closure plan was underway by Roche as a part of the Environmental and Social Impact Assessment Study. It is understood that the plan will be available only after the completion of the bankable feasibility study.



7.0 GROUNDWATER INFLOW Groundwater seepage to open pits and underground developments are important components of the site water balance and water management plan. ITASCA (November 15, 2011) estimated these inflows based on a three-dimensional regional hydrogeological model. Figure 2 summarizes the estimated groundwater inflows to the R2, R3, and R65 pits, as well as to the underground developments R2, R3, R4, R9, the shaft and the ramp.

It should be noted that ITASCA (November 15, 2011) provides a significant range of potential groundwater inflows to the mine facilities. This range is attributed in part to the assumed overburden hydraulic conductivity used in the analysis. It is recommended that the site water balance and water management infrastructure presented in this report be reviewed and updated as additional modelling inputs and site specific monitoring data become available.

Figure 2: Estimated Groundwater Inflow to the Pits and the Underground Developments (based on ITASCA, 2011)

2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033

0

300,000

600,000

900,000

1,200,000

1,500,000

‐2 ‐1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Calendar Years

Grou

ndwater inflo

ws (m

3 /year)

Operation Years

R65_Pit R2/R3_Pit R4/R9_U/G R3_U/G R2_U/G Ramp Shaft



8.0 WATER MANAGEMENT INFRASTRUCTURE The plans in Appendix B identify the proposed water management infrastructure throughout the life-of-mine. The following section presents the estimated infrastructure dimensions and capacities based on the design criteria defined in Table 4.

8.1 Ditches The rational method (MTQ, 2004) was used to calculate peak discharges for each ditch segment and for the corresponding design return period. A runoff coefficient of 1 (see Table 4) was assumed for all catchment areas. Typical cross-sections were calculated for each ditch segment assuming uniform flow conditions and Manning’s coefficients between 0.035 and 0.046 depending on riprap rock size and if the ditch is to be excavated in overburden or bedrock. The calculations assumed typical side slopes of 2.5H:1V for overburden excavations, and 1H:1V for rock excavations.

Tables 10 and 11 summarize the resulting ditch dimensions and excavation quantity estimates. Approximately 12.9 km of ditch length are required. It should be noted that the estimated dimensions and excavation quantities are based on limited topographic and bedrock elevation data (Stornoway, 2010). The ditch dimensions and layouts should be reviewed during the detailed design phase as additional site specific data become available. Additional ditches may be required along the roads depending on the details of the road network. Table 10 includes only the main site drainage network.

8.2 Culverts Twelve road-crossings were identified along the proposed ditch network. For each of the road crossings, it is proposed that corrugated steel pipe culverts be installed to convey the flow. Table 12 summarizes the 29 culverts required. The estimated total pipe length is 725 m, with pipe diameters ranging between 0.6 m and 1.50 m. Additional culverts may be required depending on the details of the road network. Table 12 includes only the culverts along the main drainage network of the site. The number and dimensions of culverts are to be confirmed during detailed design.



Table 10: Proposed Ditches - Characterization

Ditch Label Operation

Year of Construction

Calendar Year of

Construction

Catchment Area

Return Period

of Design Event

Design Discharge

(1) Length Channel Slope

Base Width

Depth (2)

Side slopes Riprap D50

ha years m3/s m m/m m m xH:1V m

125 -2 2013 108.7 100 5.9 1,340 0.3% 1.5 1.5 2.5 0.15

180 (NC)(4) -2 2013 4.5 100 1.0 230 0.3%-7.6% 1.0 1.0 2.5 0.23

181 -2 2013 3.9 100 0.6 520 2.6% 1.0 1.0 2.5 0.15 105, 103,

102 -2 2013 85.3 100 5.4 400 3.3% 2.0 1.2 1.0 no rip-rap

130 -2 2013 88.7 100 5.9 800 0.3% 1.5 1.5 2.5 0.15

120 -2 2013 114.9 100 5.9 230 0.5%-7.5% 2.0 1.5 2.5 0.46

121, 122,123 -2 2013 5.3 10 0.8 490 16.8% 1.0 1.0 2.5 0.31

109 -2 2013 8.8 10 1.2 170 1.0%-16.4% 1.5 1.0 1.0 no rip-rap

104 -2 2013 2.7 10 0.4 150 31.2% 1.0 1.0 1.0 no rip-rap

144 -2 2013 8.8 10 1.0 370 0.3%-17.8% 1.0 1.0 2.5 0.15

146 -2 2013 48.6 10 3.1 790 5.0% 1.5 1.2 2.5 0.23

140 -2 2013 63.0 10 3.4 500 0.3%-6.9% 1.5 1.2 2.5 0.31

138 (NC)(4) -2 2013 9.1 100 1.0 1,610 0.3%-9.5% 1.0 1.0 1.0 no rip-rap

170 (NC)(4) -2 2013 62.4 100 4.1 690 0.3% 2.5 1.2 2.5 0.23





Calendar Year of

Construction

Catchment Area

Return Period

of Design Event

Design Discharge

(1) Length Channel Slope

Base Width

Depth (2)

Side slopes Riprap D50

ha years m3/s m m/m m m xH:1V m

135 -2 2013 32.8 100 2.7 900 0.3%-7.9% 1.5 1.5 1.0 no rip-rap

182 (NC)(4) -2 2013 5.4 10 0.6 130 1.2% 1 1 2.5 0.15

107 1 2015 18.3 10 1.7 240 0.3%-10.8% 1.5 1.2 2.5 0.23

110 1 2015 44.7 100 3.5 850 0.7%-7.5% 1.5 1.5 2.5 0.15

139, 137 1 2015 23.1 100 2.7 830 0.3%-8.1% 1.5 1.2 2.5 0.31

115 1-4 (3) 2015-2018 40.7 100 3.5 1,660 0.4%-17.6% 1.5 1.5 2.5 0.61

Total 12,900

Notes: 1. Design discharge estimated at the downstream end of the ditch based on the 1:100 year or 1:10 year runoff event.

2. Minimum depth requirements including 0.3 m freeboard. Actual depth will vary with the terrain elevation.

3. 50% of ditch 115 length is built at the beginning of the PK deposition in Year 1 (2015); the other 50% in Year 4 (2018) of deposition.

4. (NC) identifies non-contact water ditches. The other ditches convey contact water.



Table 11: Proposed Ditches - Estimation of Quantities (3, 4)



Calendar Year of Construction

Riprap Volume

Geo-Textile Area

Estimated Excavation

- Overburden

Estimated Excavation -

Rock Estimated Granular

Fill

m3 m2 m3 m3 m3 125 -2 2013 0 0 0 30,000 18,000 180 -2 2013 590 1,280 240 1,050 0 181 -2 2013 750 2,500 1,690 440 0

105, 103, 102 -2 2013 0 0 0 1,540 0 130 -2 2013 1,440(2) 4,800(2) 6,370(2) 0(2) 0(2) 120 -2 2013 2,110 2,320 3,810 290 0

121, 122,123 -2 2013 1,890 3,100 1,860 1,730 0 109 -2 2013 0 0 0 700 0 104 -2 2013 0 0 0 300 0 144 -2 2013 720 2,400 8,310 0 0 146 -2 2013 2,880 6,260 6,890 240 0 140 -2 2013 2,430 3,980 3,100 2,030 0 138 -2 2013 0 0 470 14,990 0 170 -2 2013 2,860 6,220 5,540 1,900 0 135 -2 2013 0 0 2,820 8,510 0 182 -2 2013 290 970 920 0 0 107 1 2015 860 1,870 3,600 1,570 0 110 1 2015 2,440 8,130 9,140 0 0

139, 137 1 2015 4,040 6,620 8,530 0 0 115 1-4 (1) 2015-2018 19,370 15,880 42,040 0 0 Total 42,770 66,660 105,580 65,320 18,000

Notes: 1. 50% of ditch 115 length is built at the beginning of the PK deposition in Year 1 (2015); the other 50% in Year 4 (2018) of deposition.

2. The quantities for ditch 130 do not include the ditch section built on the ramp platform.

3. Detail works (stripping, grading, smaller fills) not included in the estimation of quantities.

4. Quantities can vary significantly if the actual topography and rock depth varies from the existing information.



Table 12: Proposed Culverts

Crossing ID Ditch Culvert Location Description

(1) Operation Year of Construction Calendar Year of

Construction

Peak Discharge

No. of Barrels Diameter

Total Pipe

Length m3/s m m

1 102 Downstream of P5 (required between 2013 and 2022) -2 2013 5.4 3 1.5 75

2 125 Downstream of P2 -2 2013 5.9 3 1.5 75

3 120 Downstream of P1, crossing with 182 (required between 2013 and 2022) -2 2013 5.9 3 1.5 75

4 120 Downstream of P1 -2 2013 5.9 3 1.5 75

5 144 Between the waste rock storage facility and the R2/R3 area -2 2013 1.0 2 0.9 50


7 (NC)(2) 182 Upstream of 182 (required between 2013 and 2022) -2 2013 0.6 2 0.9 50


9 121 Between the waste rock storage facility and R65 -2 2013 0.8 2 0.9 50

10 104 Between the waste rock storage facility and R65 -2 2013 0.4 2 0.6 50

11 109 North of the waste rock storage facility -1 2014 1.2 2 0.9 50 12 107 West of the PKC facility -1 2014 1.7 2 1.2 50

Total 29 725

Notes: 1. Location of culverts shown on Figure D3, Appendix D.

2. (NC) identifies culverts placed along non-contact water ditches. The other culverts are placed along contact water ditches.



8.3 Collection Sumps and Sedimentation Ponds The following sumps or sedimentation ponds are proposed in the order of their construction:

Camp sedimentation pond (S18): This pond is required from the start of the construction phase (Figure B1 in Appendix B). The pond will treat runoff from the camp site area throughout the life-of-mine. It can also provide TSS treatment for other collection points; however the R65 (P17) treatment unit is required for the effective treatment of large volumes of water and/or finer TSS particle sizes. Figure D4 in Appendix D presents a typical layout of the proposed camp sedimentation pond. To facilitate the attenuation of storm runoff, the camp sedimentation pond should be operated at a minimum water level during normal operating conditions.

Depending on the local topography, and the final pond placement, excavation, and fill volumes of approximately 6,000 m3 and 9,800 m3, respectively, would be required for a typical pond with a total footprint of approximately 8,000 m2 and a storage capacity of 6,700 m3. A pond of this size is predicted to settle particles greater than 6 microns in diameter during the design storm event, provided that the pond is operated at a minimum water level. A larger pond footprint and/or capacity may be required depending on how the pond is planned to be operated. Final pond dimensions and cut and fill volumes are to be determined during the detailed design phase.

Temporary sedimentation pond (S22): S22 is an existing pond, located within the footprint of the R65 pit, which will be dewatered at the beginning of the construction period. Ditch 182 will reduce the surface water runoff to S22. During the six months of construction of the R65 sump (July to December 2013), S22 will serve as temporary storage and TSS treatment point for the contact runoff from the site. From S22, the water will be pumped to the R65 (P17) treatment plant. Following the completion of the R65 sump, S22 will no longer be required and will be consumed within the R65 pit.

As with S18, S22 should be operated at a minimum water level.

Main collection pond at pit R65 (P17): This sump is the main collection point for contact water from Year -1 (2014) to the end of the mine operation (see Figure B3 in Appendix B). A treatment plant will be installed in its vicinity to treat accumulated water before discharging it to Lagopède Lake. To allow for sufficient storm storage capacity, the pond should be operated at a minimum water level.

A minimum R65 sump capacity of 312,000 m3 is required for Year -1 (2014) once the installation of the R65 treatment plant is complete. From Year 1 (2015) the planned storage capacity for the R65 sump is 506,000 m3. This capacity is anticipated to be sufficient to store operational and storm contact water runoff prior to treatment (if required) and release to Lagopède Lake. The water level at maximum operating capacity should be at least 1.0 m below the invert elevation of the incoming ditches (120 and 102 – see Figure B1 in Appendix B) to avoid potential backwater effects in the ditches. Depending on the detail design of the ditches and of the sump, this maximum operation level will be approximately 490 m elevation.

It should be noted that the required storage capacity of the R65 sump (and other sumps described in this plan) does not include any “dead storage” volume that cannot be pumped or otherwise evacuated from the sump due to limitations in the positioning of the pump intake.



Collection sump at the bottom of the shaft/ramp (P14, P15): Collection sumps are required for the underground mine to temporarily store groundwater inflows reporting to the ramp, the shaft and the underground developments (R2, R3, R4 and R9). Collected water is pumped from these sumps to the mill for process water makeup, or the R65 sump for monitoring, treatment (if required) and release to the environment. From 2017 onwards, the R2/R3 open pits will be hydraulically connected to the underground developments, and the underground sumps will also collect the runoff and the groundwater inflows reporting to these pits.

At a minimum, collection sumps will be required at the base of the shaft and ramp. Additional sumps might be required at various times along the life of mine depending on the configuration of the underground developments. An estimated total storage capacity of 15,100 m3 (in addition to any “dead storage”) is required from 2017 onwards, and is anticipated to be sufficient to attenuate the R2/R3 pit runoff. Additional storage may be required depending on the design of the underground pump/storage system. To facilitate attenuation, the sumps should be operated at a minimum water level.

Collection sump at the bottom of the R2/R3 pits (P6): Until the end of 2016, a sump will collect direct runoff and groundwater inflows to the R2/R3 pits prior to pumping to the R65 sump for monitoring, treatment (if required), and discharge to Lagopède Lake. An estimated storage capacity of 15,100 m3 (in addition to any dead storage) is required. To facilitate the attenuation, the sumps should be operated at a minimum water level.

Small localized temporary sumps may be required at various stages of the life of mine to contain storm runoff from contact areas; particularly during the construction phase of the drainage network.

8.4 Pumping Stations The following pumping stations are proposed (see Table 13) in the order of their construction and installation:

The P6 pumping station (Figure B1 in Appendix B) dewaters the natural pond located inside the R2/R3 footprint. Following pond dewatering, P6 will pump R2/R3 surface runoff and groundwater infiltration from the R2/R3 pits until an underground hydraulic connection to the underground sumps is established in Year 3 (2017). An estimated pumping capacity of 47 l/s is required. At this pumping capacity, the natural pond would be drained in less than 10 days (assuming TSS treatment is in place).

The P14 and P15 pumping stations (Figure B3 in Appendix B) are installed on the bottom of the shaft | and ramp, respectively. The pumps will send contact water reporting to these sumps to the mill or R65 (P17) sump. An estimated total combined pumping capacity of 52 l/s is required. The relative pumping capacity required at each station and the need for additional intermediate pumping stations will depend on the final underground mine design.

The P17 pumping station (Figure B3 in Appendix B) is installed at the R65 sump. At the beginning of the construction period, P17 will dewater the natural pond located inside the R65 footprint with an estimated volume of 14,700 m3. The water will be treated by the treatment plant (as required) prior to discharge to Lagopède Lake. Following dewatering, the P17 station will pump water from the sump to the treatment station or directly to Lagopède Lake if water quality permits. An estimated total pumping capacity of 177 l/s is required. Roughly 82% of this rate is required to handle the incoming runoff, while the remaining capacity is required to handle the incoming pumped flow from other sumps on the site.



Smaller localized temporary pumping stations may be required at various stages of the life of mine (e.g., during the construction phase of the drainage network) to pump storm runoff to permanent site sumps for monitoring and treatment (if required) prior to release to the environment.

Table 13: Proposed Pumping Stations

Pumping station Operation Year of Installation Calendar Year of Installation

Estimated Capacity (l/s)

Estimated Capacity (gal US/min)

P6 -2 2013 47 745 P14, P15, additional

underground points

-2 2013 52 824

P17 (R65) -2 to -1 2013 to 2014 177 2,800

8.5 Treatment Plants In addition to sedimentation ponds S18 and S22, the water management plan proposes one main point of treatment (see Table 14). The main treatment unit P17 at the R65 sump will treat contact water from the majority of the site until the end of operations and during the closure phase. The estimated required treatment capacity is approximately 126 l/s during average and dry climatic conditions and approximately 151 l/s during wet periods such as the annual snowmelt. Details on the water treatment plant are presented in under separate cover.

Table 14: Proposed Treatment Stations

Treatment Station

Operation Year of Installation

Calendar Year of Installation

Estimated Capacity

(l/s)

Estimated Capacity

(gal US/min)

P17 -2 (first unit) and -1 (second unit) 2013 (first unit) and 2014 (second unit)

126 (*) 151 (**)

2,000 (*) 2,400 (**)

Notes: (*) Required treatment capacity during average and dry climatic conditions

(**) Required treatment capacity during wet periods



9.0 MINE SITE WATER BALANCE A water balance model was developed to assist in the evaluation of the proposed water management infrastructure on a monthly basis over the life of the mine. The model will also serve as a basis for contact water quality estimations and monitoring plans.

The water balance is complemented by a mass balance of geochemical parameters associated with contact water flows on the site. The results of the mass balance, including the estimation of contact water quality at different locations on the mine site, are presented under separate cover.

The following section presents the parameters and assumptions used in the water balance model. A summary of the results is presented in Section 9.2 and Appendix E.

9.1 Model Development The water balance model is used to calculate the volume of water collected and conveyed by the proposed contact water management infrastructure under average year climate conditions over the life of mine. Extreme events were not incorporated into the model as it was assumed that the water management infrastructure will be designed, sized, and operated in a manner to intercept and contain extreme event runoff from the mine affected areas as described in Sections 4 and 8 above.

The following assumptions were made in the development of the model:

The model covers the assumed construction (May 2013 to June 2015) and operation periods (July 2015 to June 2033).

The dewatering of the R2 and R65 ponds will occur at the beginning of the construction phase. The pumped water would be treated by the first unit of the R65 treatment plant.

The processed kimberlite water content is sufficiently low (16% by mass) that there is no free-water released from the processed kimberlite following deposition within the PKC facility.

From Year 3 (2017) onwards, all runoff, direct precipitation and groundwater inflow to the pits drain by gravity to the underground sumps, where they are subsequently pumped to the mill or to the R65 sump.

All process water is supplied by the underground sumps. The R65 sump is used as backup if water is not available from the underground sumps.

For all sumps, the pump/treatment plant starts discharging/treating water as soon as there is water in the sump. The maximum treatment rate was set to 63 l/s for 2013. From 2014 onwards, the maximum treatment rate was set to 126 l/s from July to April and to 151 l/s for May and June. The pumping/treatment stops when the sump is empty. Optimization of the treatment process within the model should be considered for the next project phase.



9.2 Model Results The results of the site water balance model are summarized in Table 15 to Table 18 and in the flow logic diagrams presented on Figures E1 to E5, inclusive, in Appendix E. Time series of key water management facility flows are presented on Figures 3 and 4.

The results for operation years -2, -1, 1, 3, and 7 (2013, 2014, 2015, 2017, and 2021) coincide with key periods in the mine development plan with respect to water management.

Figure 3: Modelled R65 Treatment Rates throughout Life-of-Mine

Figure 4: Modelled Total Groundwater Inflow to the Pits Compared to Process Water Demand

0

100 000

200 000

300 000

400 000

500 000

Treated water volum

e (m

3 /mon

th)

Time (yyyy‐mm)

R65 main treatment plant (P17) ‐monthly rates

0

40,000

80,000

120,000

160,000

200,000

0

40,000

80,000

120,000

160,000

200,000

2013

‐01

2014

‐01

2015

‐01

2016

‐01

2017

‐01

2018

‐01

2019

‐01

2020

‐01

2021

‐01

2022

‐01

2023

‐01

2024

‐01

2025

‐01

2026

‐01

2027

‐01

2028

‐01

2029

‐01

2030

‐01

2031

‐01

2032

‐01

2033

‐01

Total processed

kim

berlite water (m

3 /mon

th)

Treated water volum

e (m

3 /mon

th)

Time (yyyy‐mm)

Total groundwater inflow (R2, R3, R4, R65, shaft and ramp)Total processed kimberlite waterTotal process water demand (excluding ore water)



Table 15: Water Balance Results for the Mill (Process Flows)

Notes: (1) The model results include the period May 1, 2013 to June 30, 2033, inclusive.

Table 16: Water Balance Results for the Shaft, Ramp, Pit, and Underground Works Drainage


2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033-2 -1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

InflowsOre Water 0 0 19 133 148 148 148 148 148 148 148 148 148 148 148 148 148 148 148 148 80Process Water (pumped from the shaft sump)

0 0 34 239 266 266 266 266 266 266 266 266 266 266 265 266 266 266 266 266 143

Total inflows 0 0 52 373 414 414 414 414 414 414 414 414 414 414 414 414 414 414 414 414 222Outflows

Processed Kimberlite Water 0 0 52 373 414 414 414 414 414 414 414 414 414 414 414 414 414 414 414 414 222

Flow Rate [k m3/year]Calendar Year / Operation Year

2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033-2 -1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

InflowsDirect rainfall and runoff - R2, R3 pits

99 90 99 105 100 100 99 102 100 100 100 101 100 100 101 100 100 100 100 100 50

Groundwater inflow - R2, R3 pits

11 718 711 361 154 126 109 58 48 43 37 33 29 27 21 0 0 0 0 0 0

Groundwater inflow - R2/R3/R4/R9 underground, shaft, ramp

12 126 229 355 402 525 523 628 542 509 526 537 530 594 255 301 331 359 374 390 198

Total inflows 122 934 1,039 820 656 750 732 787 690 651 662 670 659 721 377 401 431 459 474 490 248Outflows

Pumped volume to R65 treatment plant (P17)

122 934 1,005 581 390 484 466 521 424 385 396 404 393 455 112 135 165 193 208 224 106

Pumped volume to the mill 0 0 34 239 266 266 266 266 266 266 266 266 266 266 265 266 266 266 266 266 143Total Outflows 122 934 1,039 820 656 750 732 787 690 651 662 670 659 721 377 401 431 459 474 490 248




Table 17: Water Balance Results for the R65 Treatment Plant (P17)

Notes: (1) The model results include the period May 1, 2013 to June 30, 2033, inclusive. (2) The temporary sedimentation pond S22 may be required during the beginning of the construction phase (2013) depending on the availability of the R65 treatment plant.

Table 18: Modelled discharges of Treated Water to Lake Lagopède


2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033-2 -1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

InflowsDirect rainfall and runoff - Ditch P1

642 648 686 692 699 699 699 699 699 699 699 699 699 699 699 699 699 699 699 699 362

Direct rainfall and runoff - Ditch P5

73 71 446 467 488 488 488 488 488 488 488 488 488 488 488 488 488 488 488 488 256

Direct rainfall and runoff - R65

129 133 132 133 133 133 133 132 132 132 132 132 132 132 133 133 133 133 133 133 70

Groundwater inflow R65 136 391 336 342 341 432 466 648 875 819 834 828 843 810 814 808 813 789 806 485 232Pumped volume from R2/R3/R4/R9/shaft/ramp

122 934 1 005 581 390 484 466 521 424 385 396 404 393 455 112 135 165 193 208 224 106

Pumped volume from R2/ R65 ponds (dewater)

45 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Total inflows 1 147 2 176 2 605 2 215 2 051 2 236 2 251 2 488 2 618 2 523 2 549 2 550 2 555 2 584 2 245 2 263 2 297 2 302 2 333 2 028 1 026Outflows

Treated volume P17 1 147 2 176 2 605 2 215 2 051 2 237 2 251 2 488 2 618 2 523 2 549 2 550 2 555 2 584 2 245 2 263 2 297 2 302 2 333 2 028 1 026Total Outflows 1 147 2 176 2 605 2 215 2 051 2 237 2 251 2 488 2 618 2 523 2 549 2 550 2 555 2 584 2 245 2 263 2 297 2 302 2 333 2 028 1 026


2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033-2 -1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

R65 Treatment Plant 1 147 2 176 2 605 2 215 2 051 2 237 2 251 2 488 2 618 2 523 2 549 2 550 2 555 2 584 2 245 2 263 2 297 2 302 2 333 2 028 1 026Camp Sedimentation Pond Treatment Rate

28 28 28 28 28 28 28 28 28 28 28 28 28 28 28 28 28 28 28 28 14

Total treated discharge to Lake Lagopède

1 175 2 204 2 633 2 243 2 079 2 265 2 279 2 516 2 646 2 551 2 577 2 578 2 583 2 612 2 273 2 291 2 325 2 330 2 361 2 056 1 040




10.0 RECOMMENDATIONS The data used to prepare the water management plan is considered to be suitable for the feasibility level design. It is anticipated that additional local hydrological and hydrogeological data will be collected as this project advances, and it is recommended that the design and calculations presented in this report be reviewed and updated, if appropriate, as this data becomes available.

Groundwater inflows have a significant influence on site water management. It is recommended that the site water balance and water management infrastructure presented in this plan be reviewed and updated on a periodic basis as additional groundwater modelling information and site specific monitoring data become available.

The estimated dimensions of the proposed infrastructure are based on the available topographic and bedrock elevation data. To advance the detailed design of the water management infrastructure, a detailed survey of the proposed ditch and sump layouts, and further investigation of the depth to competent bedrock is recommended.

The water balance is complemented by a mass balance of geochemical parameters associated with contact water flows on the site. The results of the mass balance, including the estimation of contact water quality at different locations on the mine site, are presented under a different cover. These results should be used to review and refine where necessary the water management concept during the next engineering phase.



11.0 CLOSURE We trust this report meets your current needs. If you have any questions or comment, please feel free to contact the undersigned.

GOLDER ASSOCIATES LTD.

Vlad Rojanschi, ing., Ph.D. Ryan Mason, P.Eng. Water Resources Engineer Water Resources Engineer

Dan R. Walker, Ph.D., P.Eng. Paul M. Bedell, M.E.Sc., P.Eng. Associate, Hydrotechnical/Water Associate, Senior Geotechnical Engineer Resources Engineer

VR/RM/DRW/PMB/no/aw/np

\\bur1-s-filesrv2\final\2010\1427\10-1427-0020\doc 074 rev. 0 rep 1227_11\doc 074 rev. 0 rep 1227_11 - water mgmnt plan bcs.docx

AWongOriginal Signed and Sealed

AWongOriginal Signed





12.0 REFERENCES AMEC, 2011. Underground Primary Crushing Process Flow Diagram, Figure No. 504421-1100-49D1-0001-PC.

Submitted to Golder by e-mail from Harry Ryans dated March 3, 2011.

Golder Associates Ltd. (Golder) 2011. Renard Project Climate and Hydrological Analysis. Technical Memorandum No. 10-1427-0020/3050, Doc. No. 019 Ver 0. Submitted to Les Diamants Stornoway (Canada) Inc., dated March 22, 2011.

Itasca Denver Inc. (Itasca) 2011. – Prediction of Inflow Rates, Drawdown, and Particle Migration for the Business Case Mine Plan at Renard Diamond Mine. Submitted to Stornoway Diamond Corporation dated November 15, 2011.

Les Diamants Stornoway (Canada) Inc. (Stornoway) 2010. Renard Site Overburden Model. Submitted to Golder by e-mail from Robert Beaulieu dated September 28, 2010.

Ministère du Développement durable, Environnement et Parcs (MDDEP) 2005. Directive 019 sur l’Industrie Minière. Document no. ENV/2005/0120.

Ministère des Transports du Québec (MTQ) 2004. Manuel de conception des ponceaux.

Roche ltée (Roche) 2010. Étude environnementale de base. Projet diamantifère Renard. Rapport Sectoriel – Millieu physique. Project No. 504421 CL – 0017 Sub No. 01. Submitted to SNC-Lavalin Inc., dated September 2010.

Roche 2011. Renard Site Lake Bathymetry Data. Submitted to Golder by e-mail from Vital Boulé dated April 7, 2011.

SNC-Lavalin Inc. (SNC) 2011a. Design Criteria - Site Geographical and Climatic Conditions. Doc. No. 504421-0000-40EC-0001 Rev. #00. Submitted to Les Diamants Stornoway Inc dated March 8, 2011.

SNC 2011b. Renard Project- Overall Site Plan. Drawing no. 504421-0000-41D1-0001, Submitted to Golder by e-mail from Caroline Wilkins dated July 11, 2011.

Stornoway, 2011. Preliminary Mining Production Schedule for the Business Case Study Scenario. Submitted to Golder by e-mail from Guy Bourque, dated October 28, 2011.


December 27, 2011 Project No. 10-1427-0020/3091 Document No. 074 Rev. 0

APPENDIX A Site Plan and Mining Schedule

Stornoway Diamond Corporation(Stornoway, 2011) Les Diamants Stornoway (Canada) Inc, October 2011. Mining Production Schedule for the Business Case Scenario.

Year Total 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035

A R2/R3 Pit Reserve (BOP)

Total Tonnage (t) 12,168,499 12,168,499 12,168,499 12,168,499 7,158,580 1,158,188 - - - - - - - - - - - - - - - - - - -

Waste Rock Tonnage (t) 7,856,706 7,856,706 7,856,706 7,856,706 5,298,180 552,379 - - - - - - - - - - - - - - - - - - -

Overburden (t) 2,276,650 2,276,650 2,276,650 2,276,650 17,291 - - - - - - - - - - - - - - - - - - - -

R2 Ore Tonnage (t) 1,312,508 1,312,508 1,312,508 1,312,508 1,246,036 434,558 - - - - - - - - - - - - - - - - - - -

R2 In-situ Diamonds (carats) 1,241,951 1,241,951 1,241,951 1,241,951 1,177,036 386,018 - - - - - - - - - - - - - - - - - - -

R2 Ore Grade (c/t) 0.95 0.95 0.95 0.95 0.94 0.89 - - - - - - - - - - - - - - - - - - -

R3 Ore Tonnage (t) 722,634 722,634 722,634 722,634 597,073 171,251 - - - - - - - - - - - - - - - - - - -

R3 In-situ Diamonds (carats) 670,703 670,703 670,703 670,703 568,102 184,366 - - - - - - - - - - - - - - - - - - -

R3 Ore Grade (c/t) 0.93 0.93 0.93 0.93 0.95 1.08 - - - - - - - - - - - - - - - - - - -

Total Ore Tonnage (t) 2,035,142 2,035,142 2,035,142 2,035,142 1,843,110 605,809 - - - - - - - - - - - - - - - - - - -

Total In-situ Diamonds (carats) 1,912,654 1,912,654 1,912,654 1,912,654 1,745,137 570,384 - - - - - - - - - - - - - - - - - - -

Total Ore Grade (c/t) 0.94 0.94 0.94 0.94 0.95 0.94 - - - - - - - - - - - - - - - - - - -

R2/R3 Pit Extraction

Total Tonnage (t) 12,168,499 - - - 5,009,919 6,000,392 1,158,188 - - - - - - - - - - - - - - - - - - -

Waste Tonnage (t) 7,856,706 - - - 2,558,526 4,745,801 552,379 - - - - - - - - - - - - - - - - - - -

3 Overburden (t) 2,276,650 - - - 2,259,360 17,291 - - - - - - - - - - - - - - - - - - - -

R2 Ore Tonnage (t) 1,312,508 - - - 66,472 811,478 434,558 - - - - - - - - - - - - - - - - - - -

R2 In-situ Diamonds (carats) 1,241,951 - - - 64,916 791,017 386,018 - - - - - - - - - - - - - - - - - - -

R2 Ore Grade (c/t) 0.95 - - - 0.98 0.97 0.89 - - - - - - - - - - - - - - - - - - -

R3 Ore Tonnage (t) 722,634 - - - 125,561 425,822 171,251 - - - - - - - - - - - - - - - - - - -

R3 In-situ Diamonds (carats) 670,703 - - - 102,601 383,736 184,366 - - - - - - - - - - - - - - - - - - -

R3 Ore Grade (c/t) 0.93 - - - 0.82 0.90 1.08 - - - - - - - - -

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