EKATI Diamond Mine Interim Closure and Reclamation Plan - Closure - - PowerPoint PPT Presentation

EKATI Diamond Mine

Interim Closure and Reclamation Plan - Closure Options Evaluation Presentation Part 1: Overview

Closure Options Evaluation Meetings June 12, 2006

Presentation Overview

• Part 1: Process to Date

– Closure Plan Development Update – Community Suggestions and Concerns

• Part 2: Closure Options Presentation

– Discussion of Major Mine Components - Open Pits, Waste Rock Storage Area and Long Lake Containment Facility (LLCF). – Presentation of Closure Options for Panda/Koala/Beartooth/ Panda Diversion Channel (PDC), Misery and Fox Areas, and Long Lake Containment Facility – Risk Assessment Results (Advantages and Risks)

• Part 3: Closure Options Evaluation Process
• Part 4: Closure Plan Development - Remaining Work

Closure Options Evaluation Meetings June 12, 2006

Closure Options Evaluation Meetings June 12, 2006

• Community Input on Closure Suggestions and Concerns

– Wekweti, June 6/05 - Community visit to EKATI – Rae/Edzo, June 7/05 - Community visit to EKATI – Kugluktuk, June 13/05 - Community visit to EKATI – Lutsel K’e, June 14/05 - Community visit to EKATI – IEMA ,October 28/05 meeting, and March 31/06 Letter to BHP Billiton – IACT (Regulatory – INAC, WLWB, GNWT, DFO, EC, IEMA) November 14/06 – Kugluktuk, 8 November/05 – Meeting in community – Lutsel K’e, 15 November/05 – Meeting in community – NSMA, 13 February/06 – Written correspondence

• EKATI Interim Closure Plan Working Group

– Community, Regulatory and IEMA input on Interim Closure Plan Terms

• f Reference, January-May/06

Community & Regulatory Input Summary

Closure Options Evaluation Meetings June 12, 2006

• Open Pits

– Water

‘Establish clean water habitat’ ‘Make sure water in pit is safe’ ‘Water quality, metals and contaminants is a concern’

– Fish and Animal Health

‘pits are too deep for fish’ ‘will the fish be good to eat’ ‘Keep all biological out’ ‘Animal safety’ ‘prevent animals falling into the pits’

– General

‘don’t want to see a big hole’ ‘put rock back in pits’ ‘If the lakes are flooded quickly, where will the water come from, and will there be enough available?’

Community & Regulatory Concerns Summary Kugluktuk, Lutsel K’e, NSMA, Becho Ko, Wekweti, IEMA, IACT

Closure Options Evaluation Meetings June 12, 2006

Community & Regulatory Concerns Summary Kugluktuk, Lutsel K’e, NSMA, Becho Ko, Wekweti, IEMA, IACT

• Waste Rock Storage Areas

– Wildlife safety

‘make it safe for caribou to travel over’ ‘allow wildlife access’…’wildlife ramps – not to encourage use but to allow them to get off’ ‘ we see caribou injured from big rocks’

– Water Quality

‘ is there any sign of anything bad coming from the waste rock?’

– General

‘restore to pre-existing environment’ ‘capping source for LLCF’ ‘what kind of vegetation will grow on the waste rock’ ‘how much erosion will there be from the rock piles’

Closure Options Evaluation Meetings June 12, 2006

• Long Lake Containment Facility

– Animal Health

‘we do not want to get sick eating caribou that is sick – this is the future of our children’ ‘will the ice freeze the same, or will there be thin hidden thin spots – dangerous for traveling and caribou’

– Water Quality

‘this is our drinking water’ ‘Monitor the water that comes to the community’

– General

‘Physical stability (frozen or dry, erosion)’ ‘Plant vegetation’ ‘Don’t plant vegetation and attract wildlife’ ‘Erosion resistant cap’ ‘Tailings backfill into pits’

Community & Regulatory Concerns Summary Kugluktuk, Lutsel K’e, NSMA, Becho Ko, Wekweti, IEMA, IACT

EKATI Diamond Mine

Interim Closure and Reclamation Plan - Closure Options Evaluation Meetings Part 2: Closure Options Presentation

EKATI Diamond Mine

Panda / Koala / Beartooth / PDC Closure Options

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Mine Components

Koala Waste Rock Storage Area Koala Waste Rock Storage Area Main Camp Main Camp Koala Pit Koala Pit Koala North Pit Koala North Pit Panda Pit Panda Pit Beartooth Pit Beartooth Pit Panda Waste Rock Storage Area Panda Waste Rock Storage Area Panda Diversion Channel Panda Diversion Channel

Upper Panda Lake Upper Panda Lake Kodiak Lake Kodiak Lake

July 2005 Image

Closure Options Evaluation Meetings June 12, 2006

Panda and Koala Open Pits and Underground Mines

Closure Options Evaluation Meetings June 12, 2006

Panda, Koala and Beartooth Open Pits General Information

• General Information

– Bearclaw Pipeline redirects Bearclaw Lake flow around Beartooth Pit – Underground connections (3) between Panda and Koala – Panda Diversion Channel redirects flow around Panda and Koala Pits – Fish habitat loss has been compensated for Beartooth, Panda and Koala Lakes 2020 (U/G) 42M Koala 2010 (U/G) 37M Panda 2009 (Open Pit) 12M Beartooth LOM Completion Final Volume (m3) Pit

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth Waste Rock Storage Area Panda / Koala / Beartooth Waste Rock Storage Area

Koala Pit Koala Pit Beartooth Pit Beartooth Pit

Drainage Direction

Processed Kimberlite Coarse Rejects Processed Kimberlite Coarse Rejects Panda Pit Panda Pit Panda Diversion Channel Panda Diversion Channel

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth Waste Rock Storage Area General Information

• Physical Description

– Waste Rock Area includes:

– Coarse Rejects Pile – Landfill/Landfarm/Zone S/Contaminated Snow Containment Facility – Koala Lake Sediments – Waste granite

• Inset lifts of 10-20m deep with natural rock face repose angles of

approximately 350. Overall slope angle of 250.

• Predicted final height 512m
• Final height will be 50m above the highest point of land which falls

within the planned waste rock storage area footprint

• Fragmentation size encourages permafrost development

Closure Options Evaluation Meetings June 12, 2006

Waste Rock Pile Construction

• Rainwater and

snowmelt flow into the pile and freeze

• Large rocks at the base
• f the pile allow the pile

to Supercool through Air Convection

Dry Permafrost Rock Dry Permafrost Rock Ice Ice-

• Saturated Rock

Saturated Rock Tundra Tundra

Winter Wind

Convection Currents

Tundra Tundra

Closure Options Evaluation Meetings June 12, 2006

Panda Diversion Channel

Koala Pit Koala Pit Panda Pit Panda Pit Panda Diversion Channel Panda Diversion Channel

Closure Options Evaluation Meetings June 12, 2006

Panda Diversion Channel - General Information

• Physical Information

– Constructed in 1997 to divert flow around Panda and Koala pits, and as compensation for the loss of stream habitat during the development of EKATI. – 3.4 kms long. – The PDC receives water from North Panda, Grizzly and Buster lakes, and drains into Kodiak Lake. – In 2005 a total of 440 fish moved through the Channel’s Lower Fish Box (258 in and 182 out). A total of 254,051 eggs were estimated to have been deposited in the PDC during the spawning run, and a total

• f 3,519 fry were counted.

– 2000 Approved A&R Plan states that ‘Upon closure, culverts will be removed, original streams re-established, and frozen core dam will be breached’. – DFO expectation that PDC remains open into perpetuity.

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Closure Options

Pump Flooding Leave Channel Open Pump Flooding No Vegetation and No Access

D

PK Disposal Followed with Pump Flooding Leave Channel Open PK Disposal in Panda, followed with Pump Flooding Pump Flood Koala Wildlife Ramps and Vegetation Islands

C

Waste Rock Backfill Leave Channel Open Waste Rock Backfill Backfill into Pits

B

Natural Flooding and Reconnect Abandon Channel & Re-establish stream flow Natural Flooding Recontour

A

(approved 2000 A&R Plan)

Beartooth Pit PDC Panda/Koala Pits Waste Rock Storage Area

Option

Closure Options Evaluation Meetings June 12, 2006

155 years Natural Flooding Recontour Waste Rock Natural Flooding and Reconnect Abandon PDC, Redirect Flow Through Pit Lakes 70 years 42 years Upper Panda Lake Pit Berms Constructed Prior to Flooding Pit Wall Resloping

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Assumptions for Option A

• A – Waste Rock Storage Area (Recontour)

– Waste rock sloped to 250 average angle of repose – Irregular footprint to incorporate landform diversity – Tops of stockpiles will have irregular topography to provide perches for birds – Natural plant colonization – Wildlife access (though not stated in approved A&R Plan) – Final height will not exceed 50 m above highest topographic point with which storage area intersects

• A – Panda/Koala/Beartooth Pits (Natural Fill)

– Panda natural fill time 70 years, Koala and Koala Nth combined fill time 155 years, Beartooth natural fill time 42 years – Upper walls sloped back at select areas to a shallow angle, to form beach areas. Waste rock used to form steep rocky slopes extending from littoral zone down to first bench – Breach Panda Frozen Core Dam, re-connect stream between Panda and Koala, and re-establish flow through Panda and Koala pit lakes to Kodiak Lake – Plug underground to ensure Panda Lake level re-establishes to elevation approximate to Upper Panda Lake

• A – Panda Diversion Channel (Abandon)

– Remove culverts, re-establish original flow from nearby streams – Abandon channel and stream flow re-established through Upper Panda Lake to Panda

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Advantages and Risks Option A

• Option A Advantages

– Approved plan – Safe for wildlife on waste rock – New fish habitat created – No extra disturbance for fill pipelines – Less challenges to implement pit closure

• Option A Risks

– Loss of existing fish habitat – Long timeframe to naturally fill open pits – Significantly long fill time perceived as doing nothing – Wildlife exposed to open pit for long time – Need to upgrade PDC for limited use – New habitat less productive than current PDC – Uncertain water quality in open pits from groundwater and long fill time – Remaining highwall leads to human safety risk – Extended monitoring periods – Flooding would lead to disruption of raptor habitat – Dust migration from WRSA recontouring – Release of contaminants from currently frozen WRSA, need for blasting

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Closure Options

Pump Flooding Leave Channel Open Pump Flooding No Vegetation and No Access

D

PK Disposal Followed with Pump Flooding Leave Channel Open PK Disposal in Panda, followed with Pump Flooding Pump Flood Koala Wildlife Ramps and Vegetation Islands

C

Waste Rock Backfill Leave Channel Open Waste Rock Backfill Backfill into Pits

B

Natural Flooding and Reconnect Abandon Channel & Re-establish stream flow Natural Flooding Recontour

A

(approved 2000 A&R Plan)

Beartooth Pit PDC Panda/Koala Pits Waste Rock Storage Area

Option

Closure Options Evaluation Meetings June 12, 2006

Waste Rock Backfill Backfill into Pits PDC Remains Open Upper Panda Lake Channel

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Assumptions for Option B

• B – Waste Rock Storage Area (Backfill into pits)

– Waste rock removed to within 5m of original tundra surface – Natural plant re-colonization

• B – Panda/Koala/Beartooth Pits (Waste rock backfill)

– Panda backfill time 9 years, Koala and Koala Nth combined backfill time 7 years, Beartooth backfill time 2 years, – Dome shaped waste rock pile above each backfilled pit, – No stream flow through Panda and Koala. Channel constructed through Beartooth to re- establish flow from Bearclaw to Upper Panda

• B – Panda Diversion Channel (Leave open)

– Remove culverts – Slope back canyon section to widen channel and stabilize channel banks

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Advantages and Risks Option B

• Option B Advantages

– Reduces overall height of Waste Rock Storage Area – No pit lake concerns long-term

• Option B Risks

– Same Waste rock area footprint remains – Degradation of permafrost below Waste rock area leads to erosion and contaminants release – Remobilization of contaminants from Waste rock storage – Increased dust from waste rock movement – Jeopardize future mine life and economics – Additional risk of spills and greenhouse gases due to longer use of mining fleet – Less flexibility for processed kimberlite in open pits – Potentially reduces availability of clean waste rock for LLCF cover – Long-term maintenance of PDC to maintain stability of channel – Fish over spillway into open pit during high flow events

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Closure Options

Pump Flooding Leave Channel Open Pump Flooding No Vegetation and No Access

D

PK Disposal Followed with Pump Flooding Leave Channel Open PK Disposal in Panda, followed with Pump Flooding Pump Flood Koala Wildlife Ramps and Vegetation Islands

C

Waste Rock Backfill Leave Channel Open Waste Rock Backfill Backfill into Pits

B

Natural Flooding and Reconnect Abandon Channel & Re-establish stream flow Natural Flooding Recontour

A

(approved 2000 A&R Plan)

Beartooth Pit PDC Panda/Koala Pits Waste Rock Storage Area

Option

Closure Options Evaluation Meetings June 12, 2006

Upper Panda Lake PDC Remains Open 8 years 7 years 3 years PK Disposal Followed with Pump Flooding No Recontour Wildlife Ramps and Vegetation Islands Pit Berms Constructed Prior to Flooding

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Assumptions for Option C

• C – Waste Rock Storage Area (Wildlife ramps, pocket vegetation,

recontour)

– Approximately 7 wildlife access ramps, 30m wide – No re-contouring – Vegetation Islands

• C – Panda and Beartooth Pits (Processed kimberlite disposal and

pump flood). Pump flood Koala

– Tailings disposal in Panda and Beartooth pits to 20m below final water surface, with pumped fresh water cap. Processed kimberlite fill time for Panda approx 6 yrs, and Beartooth approx 2 yrs. Pumped cap fill time for Beartooth and Panda is 1 yr each. Pump fill Koala pit 8 yrs. – Spillway constructed around Panda Frozen Core Dam to enable freshet flow into Panda and Koala pit lakes, rock weir constructed at Koala outlet to prevent fish passage into pit lakes

• C – Panda Diversion Channel (Leave open)

– Remove culverts – Slope back canyon section to widen channel and stabilize channel banks

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Advantages and Risks Option C

• Option C Advantages

– Reduced tailings deposition Cell D – Eliminates need for new fish passage and habitat construction – Less impact on source lakes for open pit filling – Provides progressive reclamation of LLCF earlier – Access for wildlife on waste rock for relief from insects

• Option C Risks

– Underground safety issues related to plug for tailings fill – Tailings reclaim water system more complicated – Success of vegetation on Waste rock storage area uncertain – Downstream effect from taking water from Cell E – Fish returning to isolated pit lakes by accident – Extended monitoring periods – Long-term maintenance of PDC to maintain stability of channel – Fish over spillway into open pit during high flow events – Dust migration from WRSA recontouring access ramps

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Closure Options

Pump Flooding Leave Channel Open Pump Flooding No Vegetation and No Access

D

PK Disposal Followed with Pump Flooding Leave Channel Open PK Disposal in Panda, followed with Pump Flooding Pump Flood Koala Wildlife Ramps and Vegetation Islands

C

Waste Rock Backfill Leave Channel Open Waste Rock Backfill Backfill into Pits

B

Natural Flooding and Reconnect Abandon Channel & Re-establish stream flow Natural Flooding Recontour

A

(approved 2000 A&R Plan)

Beartooth Pit PDC Panda/Koala Pits Waste Rock Storage Area

Option

Closure Options Evaluation Meetings June 12, 2006

Upper Panda Lake PDC Remains Open 8 years 7 years 4 years Pump Flooding No Vegetation, No Access Pit Berms Constructed Prior to Flooding

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Assumptions for Option D

• D – Waste Rock Storage Area (No Vegetation, No access)

– No wildlife access ramps – Side slopes remain as is to promote/maintain permafrost, – Dome top to encourage run-off – Natural plant colonization

• D – Panda / Koala / Beartooth Pits (Pumped flood)

– Pump fill time for Panda is 7 yrs, Koala and Koala North combined is 8 yrs, Beartooth is 4 yrs – Source lakes: LLCF, Lac de Gras – Spillway constructed around Panda Frozen Core Dam to enable freshet flow into Panda and Koala pit lakes, rock weir constructed at Koala outlet to prevent fish passage into pit lakes

• D – Panda Diversion Channel (Leave open)

– Remove culverts – Slope back canyon section to widen channel and stabilize channel banks

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Advantages and Risks Option D

• Option D Advantages

– Open pits fill faster from pump flooding – Eliminates need for new fish passage and habitat construction – Waste rock area remains frozen and stable

• Option D Risks

– Safety concerns for wildlife on Waste rock area – Pumping from Cell D creates uncertain effect on LLCF downstream flow – Uncertain water quality in open pits – Long-term dust migration from wind erosion – Long-term maintenance of PDC to maintain stability of channel – Fish over spillway into open pit during high flow events – Effect on source lakes and catchment from pump flooding – Pit wall instability impacts water quality in pit – Remaining highwall leads to wildlife falling into open pits – Lack of reshaping does not conform to community expectations

Closure Options Evaluation Meetings June 12, 2006

Panda / Koala / Beartooth / PDC Closure Options

Pump Flooding Leave Channel Open Pump Flooding No Vegetation and No Access

D

PK Disposal Followed with Pump Flooding Leave Channel Open PK Disposal in Panda, followed with Pump Flooding Pump Flood Koala Wildlife Ramps and Pocket Vegetation

C

Waste Rock Backfill Leave Channel Open Waste Rock Backfill Backfill into Pits

B

Natural Flooding and Reconnect Abandon Channel & Re-establish stream flow Natural Flooding Recontour

A

(approved 2000 A&R Plan)

Beartooth Pit PDC Panda/Koala Pits Waste Rock Storage Area

Option

EKATI Diamond Mine

Misery and Fox Closure Options

Closure Options Evaluation Meetings June 12, 2006

Misery Open Pit – July 2005

Closure Options Evaluation Meetings June 12, 2006

Misery Mine Components

Misery Pit Misery Pit Waste Rock Storage Area Waste Rock Storage Area Lac de Gras Lac de Gras Temporary Ore Stockpiles Temporary Ore Stockpiles

Closure Options Evaluation Meetings June 12, 2006

Misery Area

July 2005 Image

Waste Rock Storage Area Waste Rock Storage Area Misery Pit Misery Pit Misery Camp Misery Camp

Closure Options Evaluation Meetings June 12, 2006

Fox Area Components

July 2005 Image

Waste Rock Storage Area Waste Rock Storage Area Fox Pit Fox Pit

Waste kimberlite (w ill be covered w ith granite cap) Waste kimberlite (w ill be covered w ith granite cap) Low grade ore (w ill be covered w ith granite cap) Low grade ore (w ill be covered w ith granite cap)

Closure Options Evaluation Meetings June 12, 2006

Fox Area Pictures

View from approx, 2 km View from approx, 2 km View from approx, 8 km View from approx, 8 km

Closure Options Evaluation Meetings June 12, 2006

Misery Open Pit and Waste Rock Storage Area General Information

• Open Pit

– Current Life of Mine Plan 2018 (includes Misery Pushback) – Final Open Pit volume 26M m3 – Misery would be a headwater pit lake – Fish habitat loss has been compensated for Misery Lake

• Waste Rock Storage Area

– Contains layered granite and biotite schist – Biotite schist is potentially acid generating – Waste rock storage area was capped with 5m granite in 2005 as part of progressive reclamation and for Temporary Suspension of Operations

Closure Options Evaluation Meetings June 12, 2006

Fox Open Pit and Waste Rock Storage Area General Information

• Open Pit

– Current Life of Mine Plan 2014 – Final open pit volume 68M m3 – Fox would be a headwater pit lake – Fish habitat loss has been compensated for Fox Lake

• Waste Rock Storage Area

– Contains lake sediments, waste granite and waste kimberlite

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Area Closure Options

Pump Flooding No Vegetation, No Access

D

Pump Flooding No Recontour, Wildlife Ramps, Vegetations Islands

C

Waste Rock Backfill Backfill into Pit

B

Natural Flooding Recontour, Vegetation Islands

A

(approved 2000 A&R Plan)

Open Pit Waste Rock Storage Area

Option

Closure Options Evaluation Meetings June 12, 2006

Natural Flooding Recontour Waste Rock Slopes Natural Re-colonization Pit Berms Constructed Prior to Flooding 180 years

Closure Options Evaluation Meetings June 12, 2006

Natural Flooding 542 years Natural Re-colonization Recontour Waste Rock Pit Berms Constructed Prior to Flooding

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Assumptions for Option A

• A - Waste Rock Storage Area (Recontour)

– Waste rock sloped to 250 average angle of repose – Irregular footprint to incorporate landform diversity – Tops of stockpile will have irregular topography to provide perches for birds – Natural plant colonization – Wildlife access (though not stated in approved A&R Plan) – Final height will not exceed 50 m above highest topographic point with which storage area intersects

• A – Open Pit (Natural Fill)

– Misery natural fill time 180 years – Fox natural fill time is 542 years – Misery outflow re-established to Lac de Gras - southeast of pit – Rock weir at Misery outflow to prevent fish access to Misery pit lake – Fox outflow connected to 1 Hump Lake

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Advantages and Risks Option A

• Option A Advantages

– Approved plan – Safe wildlife access over waste rock storage area – No extra disturbance for fill pipelines or source lakes – Less challenges to implement pit closure

• Option A Risks

– Long timeframe to naturally fill open pit – Wildlife exposed to open pit for long time – Uncertain water quality in open pit – Extended monitoring period – Significantly long fill time perceived as doing nothing – Potential for poor water quality in pit from groundwater and long fill time – Dust migration from recontouring waste rock storage area – Release of contaminants from currently frozen waste rock storage area, need for blasting – Human safety concern from snowmachines over the Misery waste rock storage area, proximity to winter road, Lac de Gras

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Area Closure Options

Pump Flooding No Vegetation, No Access

D

Pump Flooding No Recontour, Wildlife Ramps, Vegetations Islands

C

Waste Rock Backfill Backfill into Pit

B

Natural Flooding Recontour

A

(approved 2000 A&R Plan)

Open Pit Waste Rock Storage Area

Option

Closure Options Evaluation Meetings June 12, 2006

Backfill Backfill into Pit

Closure Options Evaluation Meetings June 12, 2006

Waste Rock Backfill Backfill into Pit

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Assumptions for Option B

• B - Waste Rock Storage Area (Backfill into pit)

– Waste rock removed to within 5m of original tundra surface – Natural plant re-colonization

• B – Open Pit (Waste rock backfill)

– Misery backfill 5 years – Fox backfill time 11 years – Dome shaped waste rock pile above backfilled pit – Misery - no stream connection with Lac de Gras – Fox – no stream connection with Lac de Gras

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Advantages and Risks Option B

• Option B Advantages

– Reduces overall height of waste rock storage area – No pit lake concerns long-term

• Option B Risks

– Same waste rock area footprint remains – Remobilization of contaminants from moving waste rock storage area – Increased dust from waste rock movement – Jeopardize future mine life and economics – Additional risk of spills and greenhouse gases due to longer use of mining fleet – Degradation of permafrost in rock storage area leads to erosion and contaminants release

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Closure Options

Pump Flooding No Vegetation, No Access

D

Pump Flooding No Recontour, Wildlife Ramps, Vegetations Islands

C

Waste Rock Backfill Backfill into Pit

B

Natural Flooding Recontour

A

(approved 2000 A&R Plan)

Open Pit Waste Rock Storage Area

Option

Closure Options Evaluation Meetings June 12, 2006

Pump Flooding Vegetation Islands No Recontouring Wildlife Ramps Pit Berms Constructed Prior to Flooding 2 years

Closure Options Evaluation Meetings June 12, 2006

Pump Flooding Vegetation Islands No Recontour Wildlife Ramps 13 years Pit Berms Constructed Prior to Flooding

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Assumptions for Option C

• C - Waste Rock Storage Area (No recontour)

– Wildlife access ramps, 30m wide – No re-contouring – Vegetation Islands

• C – Open Pit (Pump Flood)

– Misery fill time 2 years – Fox fill time 13 years – Source lake for pit flooding is LLCF or Lac de Gras – Misery - stream re-connection with Lac de Gras

– Rock weir at Misery outflow to prevent fish access to Misery pit lake – Fox – stream connection with 1 Hump Lake

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Advantages and Risks Option C

• Option C Advantages

– Access for wildlife on waste rock for relief from insects – Provides safe wildlife access – Open pits fill faster from pump flooding – Waste rock pile remains frozen, consistent with design criteria

• Option C Risks

– Success of vegetation on Waste Rock Storage Area uncertain – Uncertain water quality in open pits – Possible effect on source lake for pump flooding – Long term dust migration from Waste Rock Storage Area – New material for ramp fill may cause problems at borrow locations

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Closure Options

Pump Flooding No Vegetation, No Access

D

Pump Flooding No Recontour, Wildlife Ramps, Vegetations Islands

C

Waste Rock Backfill Backfill into Pit

B

Natural Flooding Recontour

A

(approved 2000 A&R Plan)

Open Pit Waste Rock Storage Area

Option

Closure Options Evaluation Meetings June 12, 2006

Pump Flood No Vegetation, No Access Access Blocked Pit Berms Constructed Prior to Flooding 2 years

Closure Options Evaluation Meetings June 12, 2006

Pump Flooding No Vegetation, No Access Access Blocked 13 years Pit Berms Constructed Prior to Flooding

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Assumptions for Option D

• D - Waste Rock Storage Area (No Vegetation, No Access)

– No wildlife access ramps – Side slopes remain as is to promote/maintain permafrost, – Dome top to encourage run-off – Natural plant colonization

• D – Open Pit (Pump Flood)

– Misery fill time 2 years – Fox fill time 13 years – Misery - stream re-connection with Lac de Gras – Rock weir at Misery and Fox outflows to prevent fish access to Misery pit lake – Fox – stream connection with1 Hump Lake

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Advantages and Risks Option D

• Option D Advantages

– Waste Rock Storage Area remains frozen and stable, consistent with design criteria – Open pits fill faster from pump flooding – Reduces access and safety concerns for wildlife on waste rock pile

• Option D Risks

– Uncertain water quality in open pits – Possible effect on source lakes for pump flooding – Lack of reshaping does not conform to community expectations – Pit wall instability from faster filling may lead to water quality impacts in pit – Remaining highwall leads to wildlife falling into open pits – Human safety concern from snowmachines over the Misery waste rock storage area, proximity to winter road, Lac de Gras – Long-term dust migration from wind erosion – In pit kimberlite stockpile needs to be relocated to Waste Rock Storage Area and cover

Closure Options Evaluation Meetings June 12, 2006

Misery and Fox Closure Options

Pump Flooding No Vegetation, No Access

D

Pump Flooding No Recontour, Wildlife Ramps, Vegetations Islands

C

Waste Rock Backfill Backfill into Pit

B

Natural Flooding Recontour

A

(approved 2000 A&R Plan)

Open Pit Waste Rock Storage Area

Option

EKATI Diamond Mine

Long Lake Containment Facility (LLCF) Closure Options

Closure Options Evaluation Meetings June 12, 2006

LLCF Components at end of Mine Life (2020)

July 2005 Image

Cell A Cell B Cell C Cell D Cell E

Diversion Ditch Diversion Ditches to direct flow into Cell E

Closure Options Evaluation Meetings June 12, 2006

LLCF Area Pictures

Drainage Channels

• n Cell C

Drainage Channels

• n Cell C

Outlet Dam Outlet Dam Cell B Cell B Dyke C Dyke C

Closure Options Evaluation Meetings June 12, 2006

LLCF General Information

• Physical Description

– Facility divided into 5 cells (A-E) – Water discharge from Cell E is prevented by the Outlet Dam (frozen core) – Water is only pumped from the facility when it meets water discharge criteria – Facility receives fine fraction of processed kimberlite (< 0.55mm) – Flocculants and coagulants are mixed with the processed kimberlite to encourage sedimentation – Mineralogy of the extra fine processed kimberlite is illite and smectite clays (Panda contains least, and Fox contains greatest proportion of smectite clays) – Fish habitat loss has been compensated for Long Lake – Vegetation research in Cell B since 2000 – Recent 5 year review

– design changes with intent to discharge as much of the processed kimberlite into upper cells and redirect to open pit(s) when available – Design changes to move fresh water around facility and minimize water inflows into containment cells

Closure Options Evaluation Meetings June 12, 2006

LLCF Area Closure Options

Combination Waste Rock and Vegetation with Ponds

C

Direct Vegetation with Ponds

B

Waste Rock Cover with Ponds

A

LLCF Closure Options Option

Closure Options Evaluation Meetings June 12, 2006

Option A - Waste Rock Cover with Ponds

Cell C Cell D Cell E Cell A Cell B

Closure Options Evaluation Meetings June 12, 2006

LLCF - Assumptions for Option A

• Option A (Waste rock cover with ponds)

– Waste rock cover 1.5 – 2 m thick of granite and lake sediments – Outlet Dam breached and Diversion Systems decommissioned at closure – Rock weir at outlet to prevent fish access to facility – Option 3aM (Waste Water and Processed Kimberlite Management Plan)

– external drainage systems on east perimeter of Cell B, and west of Cells D and E – gently sloping, well drained beaches, – residual ponds in Cells A, B and C, (small ponds A and B and large pond in C), – interface shorelines where beach deposits meet the ponds.

Closure Options Evaluation Meetings June 12, 2006

LLCF Advantages and Risks Option A

• Option A Advantages

– No exposed process kimberlite for erosion – No vegetation that can create metals uptake concerns from kimberlite – Stable erosion protection from coarse waste rock – Fine kimberlite remains submerged in water – Easier construction techniques

• Option A Risks

– Pore water quality discharge uncertainty – Failure of rock cover from unstable fine tailings below – Thawing of ice lenses in tailings causes degradation and settlement of cover – Dust migration during cover construction – Availability of clean rock for cover – Risk of fish returning to ponds in LLCF

Closure Options Evaluation Meetings June 12, 2006

LLCF Area Closure Options

Combination Waste Rock and Vegetation with Ponds

C

Direct Vegetation with Ponds

B

Waste Rock Cover with Ponds

A

LLCF Closure Options Option

Closure Options Evaluation Meetings June 12, 2006

Option B – Direct Vegetation with Ponds

Cell B Cell A Cell C Cell D Cell E

Closure Options Evaluation Meetings June 12, 2006

LLCF - Assumptions for Option B

• Option B (Direct Vegetation with Ponds)

– Vegetation cover of grasses and shrubs – Outlet Dam breached and Diversion Systems decommissioned at closure – Rock weir at outlet to prevent fish access to facility – Option 3aM (Waste Water and Processed Kimberlite Management Plan)

– external drainage systems on east perimeter of Cell B, and west of Cells D and E – gently sloping, well drained beaches, – residual ponds in Cells A, B and C, (small ponds A and B and large pond in C), – interface shorelines where beach deposits meet the ponds.

Closure Options Evaluation Meetings June 12, 2006

LLCF Advantages and Risks Option B

• Option B Advantages

– Provides large area of vegetation – Fine kimberlite remains submerged in water – Promotes freezing of kimberlite

• Option B Risks

– Pore water quality discharge uncertainty – Long-term success of vegetation is uncertain – Greater chance of metals uptake from kimberlite – Erosion of kimberlite from poor vegetation – Chance of long-term dust from poor vegetation success – Risk of fish returning to ponds in LLCF – Settlement of drainage channel leads to kimberlite erosion – Direct ingestion of kimberlite by caribou

Closure Options Evaluation Meetings June 12, 2006

LLCF Area Closure Options

Combination Waste Rock and Vegetation with Ponds

C

Direct Vegetation with Ponds

B

Waste Rock Cover with Ponds

A

LLCF Closure Options Option

Closure Options Evaluation Meetings June 12, 2006

Option C – Combination Waste Rock and Vegetation with Ponds

Cell A Cell D Cell B Cell E Cell C

Closure Options Evaluation Meetings June 12, 2006

LLCF - Assumptions for Option C

• Option C (Combination waste rock and vegetation with ponds)

– Waste rock cover 1.5 – 2 m thick of granite and lake sediments with intermixed vegetation cover of grasses and shrubs – Outlet Dam breached and Diversion Systems decommissioned at closure – Rock weir at outlet to prevent fish access to facility – Option 3aM (Waste Water and Processed Kimberlite Management Plan)

– external drainage systems on east perimeter of Cell B, and west of Cells D and E – gently sloping, well drained beaches, – residual ponds in Cells A, B and C, (small ponds A and B and large pond in C), – interface shorelines where beach deposits meet the ponds.

Closure Options Evaluation Meetings June 12, 2006

LLCF Advantages and Risks Option C

• Option C Advantages

– Provides areas of vegetation – Fine kimberlite remains submerged in water

• Option C Risks

– Pore water quality discharge uncertainty – Long-term success of vegetation is uncertain – Greater chance of metals uptake from kimberlite compared to rock only cover – Less protection of kimberlite and increased erosion risk compared to rock only cover – Dust migration prior to stable vegetation – Settlement of drainage channel leads to erosion of kimberlite – Failure of rock cover from unstable fine tailings below – Risk of fish returning to ponds in LLCF – Landform is unstable which may lead to wildlife safety issues

Closure Options Evaluation Meetings June 12, 2006

LLCF Area Closure Options

Combination Waste Rock and Vegetation with Ponds

C

Direct Vegetation with Ponds

B

Waste Rock Cover with Ponds

A

LLCF Cover Options Option

EKATI Diamond Mine

Interim Closure and Reclamation Plan - Closure Options Evaluation Meetings Part 3: Closure Options Evaluation Process

Closure Options Evaluation Meetings June 12, 2006

Closure Options Evaluation Process

• Closure Options Presentation June 9-25th
• IACT, IEMA, Communities of Kugluktuk, Lutsel K’e, NSMA, Yellowknives

Dene and Tlicho Government

• Communities Minesite Tour July 7-9th

– 1 representative from each of regulatory, and 4 from each of above communities – Arrive at EKATI evening Friday July 7th – Presentation and Tours of Open Pits, PDC, Waste Rock Storage Areas, and LLCF Saturday and Sunday, July 8th and 9th – Return to Yellowknife Sunday evening July 9th

• Closure Options Evaluation Workshop July 18-21st (Yellowknife)

– 4 day workshop to evaluate closure options – Evaluation process simplified for community participation

EKATI Diamond Mine

Interim Closure and Reclamation Plan - Closure Options Evaluation Meetings Part 4: Remaining Work

Closure Options Evaluation Meetings June 12, 2006

Closure Options Evaluation Meetings June 12, 2006

Your participation in the Evaluation Process

• You are asked to:

– Select a representative who will participate in the July minesite tour and the Closure Options Evaluation Workshop – Review the closure options presented and be ready to evaluate the

• ptions with BHP Billiton at the Closure Options Evaluation Workshop