DE BEERS GAHCHO KU WATER LICENCE AMENDMENT HEARING PRESENTATION - - PowerPoint PPT Presentation

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DE BEERS GAHCHO KU WATER LICENCE AMENDMENT HEARING PRESENTATION - - PowerPoint PPT Presentation

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DE BEERS GAHCHO KU WATER LICENCE AMENDMENT HEARING PRESENTATION Lynx Room, Chateau Nova, Yellowknife July 25-26, 2018 AGENDA Summary of Amendment Application - Changes to mine plan and mine water management - Overview of amendment

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Lynx Room, Chateau Nova, Yellowknife July 25-26, 2018

DE BEERS GAHCHO KUÉ WATER LICENCE AMENDMENT HEARING PRESENTATION

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1 The De Beers Group of Companies

  • Summary of Amendment Application
  • Changes to mine plan and mine water management
  • Overview of amendment application
  • Key Responses to Interventions from DFO, ECCC,

and GNWT

  • Water use
  • Effluent quality criteria (EQC)
  • Amendments to SNP
  • Discharge timing and monitoring
  • Response framework and action levels
  • Air quality
  • Offsetting plan and downstream flow mitigation

AGENDA

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2 The De Beers Group of Companies

  • Gahcho Kue is owned by a Joint Venture Partnership
  • Located 280 km northeast of Yellowknife, 140 km from Lutsel K’e
  • Open Pit Mine: 5034 Pit, Hearne Pit, and Tuzo Pit
  • Mine Life: 2 Years Construction, 11.6 yrs Operation, 2 yrs Active Closure, and 19 yrs re-filling Kennady Lake

GAHCHO KUÉ MINE

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3 The De Beers Group of Companies

  • A joint

joint is a break (fracture) of natural origin in the continuity of the rock

  • A joint set

joint set is a family of parallel, evenly spaced joints

  • When joint sets

joint sets are blasted, blast pattern is affected

  • Rock is not only breaking along vertical blast lines,

but also along the joint sets

  • Results in reduction of the catch benches – leading

to safety issue for workers below

  • 5034 pit has joint sets on the eastern wall
  • Issue extends to Tuzo and Hearne pits
  • Necessary to re-design slope walls to accommodate

additional break-back and preserve bench widths for safety

BASIS FOR THE WL AMENDMENT

BFA 85°

90°

BFA 70°

2m 6m 24m

Planned break- back Actual break- back

A A Ne New Chall Challenge f for the Mine – r the Mine – Joint sets in

  • int sets in all three pits

all three pits

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4 The De Beers Group of Companies

KEY OUTCOME – EXTRA MINE ROCK

  • Pit shapes will change; wall slopes decrease
  • Additional mine rock will be produced
  • Planned case = 65 Mt
  • Worst case = 100 Mt
  • Where does the extra mine rock go?
  • Alternatives Analysis conducted to examine

best design for mine rock management

  • Parameters considered:
  • Containment within Controlled Area
  • Minimized footprint on land and in water
  • Close proximity to pits
  • Minimized height increase
  • Technical feasibility
  • Feedback received from Aboriginal Parties

during previous reviews

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5 The De Beers Group of Companies

WEST MINE ROCK PILE – SELECTED DESIGN

Sele Selected and Refi and Refine ned Opti Option

  • n

Capacity 130 Mt Height increase 35 m Total height 135 m Proximity to pits Close Land increase 7.1 ha Water increase 55.4 ha Key Features:

  • Footprint within Controlled

Boundary

  • Drainage channel from D

lakes required at closure

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6 The De Beers Group of Companies

Operations Operations

  • Increased footprint
  • Adjustments to water management
  • Additional camp occupancy and annual camp

water intake

  • Additional mining equipment and operating hours
  • Some additional infrastructure within camp
  • Life of mine extended by 7 months

Closur Closure

  • Longer to refill Kennady Lake
  • Constructed diversion channel required to

reconnect D Watershed to Kennady Lake

HOW DOES THIS LARGER MINE ROCK PILE CHANGE AFFECT THE MINE?

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7 The De Beers Group of Companies

Additio tional Y al Year of Dischar

  • f Discharge t

to Lak Lake N1 N11 1 (Y (Yea ear 4; r 4; Sept Septem ember t r to No November 2020) 2020)

  • Annual allotment remains same as licenced = 3.45 Mm3/yr
  • Discharge planned for Sep 1 to Nov 1
  • EQC evaluation report submitted
  • If EQC are met in WMP beyond Year 4 (2020), discharge can continue under same conditions

Discharg Discharge fr from

  • m Area

Area 7 7 to Area 8 Area 8

  • Supplemental source of downstream flow mitigation water to Area 8
  • ~1.55 Mm3 as available from natural watershed runoff during Life of Mine (~4 time periods during LoM)
  • EQC evaluation report submitted

Conti Contingency opti y option f

  • n for st

r stora

  • rage of WMP
  • f WMP water in

r in Area Area 7 7

  • WMP water storage could be temporary (i.e., pumped back to WMP or a pit)
  • Water discharged to Area 8 if contingency EQC are met (EQC evaluation in response to IR #1)

CHANGES TO PLANNED DISCHARGE TO LAKE N11 AND AREA 8

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RESPONSES TO INTERVENTIONS

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9 The De Beers Group of Companies

CAMP WATER USE AND DEFINITION OF MODIFICATION

Wa Wate ter U Use

  • De Beers is seeking 45,000 m3/y, with a bridging amendment for 2018 = 35,000 m3/y
  • GNWT Recommendation 5

ecommendation 5.1 stated no concern with request

  • De Beers requested confirmation that no additional sampling would be required during discharges

that crossed the anniversary date of the Water Licence.

  • GNWT Recommendation 5

ecommendation 5.2 supported the request as long a regular SNP monitoring occurred during discharge

Def Defini niti tion of Modi

  • n of Modifi

ficati cation

  • n
  • De Beers stands by the request for amendment to the term ‘modification’ under Part A of the Water

Licence, where the definition of modification omits the exclusion of expansion (GNW (GNWT T Recommendation 6. commendation 6.1) 1)

  • Rationale based on recent MVLWB decisions where the increase in size (or expansion) of several

internal dykes (D, A1, and L) were considered modifications

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10 The De Beers Group of Companies

  • The proposed wording by GNWT for condition Part

G, Item 29 of the Water Licence is acceptable to De Beers (GNW GNWT Recommendation 2.3. commendation 2.3.1a 1a)

  • Inclusion of pre-discharge WQ results from

additional SNP stations (e.g., SNP 06) close to compliance stations for consideration by the Inspector provides increased flexibility

  • Monitoring results provided to the Inspector prior

to any discharge will include all EQC parameters, as well as any required toxicity testing outlined in the Water Licence (GNW GNWT Recomm commendation dation 2.3. 2.3.1b)

AMENDMENTS TO SNP

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11 The De Beers Group of Companies

  • Same approach used to set water quality-based EQC

for the Mine as in WL MV2005L2-0015

  • Based on guidance from AEP (1995) and USEPA (1991)
  • Consistent with water quality-based EQC in Water Licences

for Snap Lake Mine and Ekati Mine (Jay Project)

  • Step-wise process for both Area 8 and Lake N11;

described in detail at the Technical Sessions

EFFLUENT QUALITY CRITERIA

  • EQC developed in the EQC Report (Attachment 3 of the Water Licence Application)

– WMP to Lake N11: chloride, fluoride, sulphate, nitrate, total ammonia, total phosphorus, and total

aluminum, chromium, copper and iron

– Area 7 (mostly composed of natural watershed runoff) to Area 8: total copper

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12 The De Beers Group of Companies

Area 7 Discharge Area 7 Discharge to Area 8 Area 8

  • De Beers developed contingency EQC for discharge from Area 7 to Area 8 if WMP water is

transferred to Area 7

  • Contingency EQC developed that that would only be triggered if water from WMP is transferred to Area

7(GNWT R Recommendation 2 commendation 2.2.1)

  • Prior to discharge under contingency EQC condition, De Beers will use existing processes to

evaluate the volume of water that could be transferred from the WMP to Area 7(ECCC CCC Recommendation 4. commendation 4.1a 1a)

  • Based on water chemistry in WMP and Area 7, and volume of water in Area 7 at the time of transfer, so

contingency EQC can be met

  • Inspector would confirm prior to discharge

EFFLUENT QUALITY CRITERIA

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13 The De Beers Group of Companies

Lak Lake N1 N11 EQC 1 EQC

  • De Beers acknowledges supporting recommendations for proposed EQC (GNW

GNWT Recommend commendations 2. ations 2.1. 1.1 t 1 to 2. 2.1. 1.13, 2.2.2b , 2.2.2b)

SS SSWQOs and Nitr WQOs and Nitrogen Managem

  • gen Management

nt

  • De Beers has agreed to use CCME Protection of Aquatic Life guideline as the SSWQO for cadmium

(ECCC R ECCC Recommendation 4.2 commendation 4.2)

  • De Beers will continue to review measured copper concentrations and condition of the aquatic

biota in the receiving environment to evaluate potential effects (GNW GNWT R Recommendation commendation 2.2.2a 2.2.2a and b and b)

  • De Beers is committed to reducing nitrate loading to WMP (GNW

GNWT R Recomm commendations 2. dations 2.1.4 1.4 and and 2. 2.1.6 1.6)

  • Nitrogen management processes will be included in the Explosive Management Plan; the Plan will be

updated to include management measures to reduce nitrate loadings to the WMP

EFFLUENT QUALITY CRITERIA

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14 The De Beers Group of Companies

Discharge t Discharge to Lak Lake N1 N11 fr 1 from the WMP

  • m the WMP af

after Y Year 4 ar 4 (2020) (2020)

  • De Beers requests EQC proposed for WMP discharge to Lake N11

remain applicable for Life of Mine and not limited to just Year 4 (GNW GNWT Recommendation 2. commendation 2.1. 1.14)

  • EQC proposed for discharge to Lake N11 are projected to be

achievable in Year 5 (2021) for EQC parameters, except chloride, nitrate, total phosphorus, and total chromium

  • SSWQO will be met for EQC parameters for discharges to Lake N11

Year 5+ at MAC EQC, with exception of total phosphorus, aluminum, chromium, copper, and iron

  • Projected concentrations only slightly higher than SSWQO and limited to

brief periods during under-ice conditions

  • Risk of any potential adverse effects low

EFFLUENT QUALITY CRITERIA

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15 The De Beers Group of Companies

Discharge t Discharge to Lak Lake N1 N11 fr 1 from the WMP

  • m the WMP af

after Y Year 4 ar 4 (2020) (2020)

  • De Beers will continue to monitor water quality in WMP

under SNP and Lake N11 under SNP/AEMP to inform whether EQC can be met (ECCC R CC Recommen commendation dation 4. 4.3a 3a)

  • De Beers will not discharge if EQC are not met (Year 5 or any

subsequent year)

  • Should EQC be met in the WMP beyond Year 4 (2020), De

Beers seeks flexibility to discharge to Lake N11

  • Allows for operational flexibility, with security that the receiving

environment remains protected

EFFLUENT QUALITY CRITERIA

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16 The De Beers Group of Companies

Water Quality Monit r Quality Monitorin ring and Modelling and Modelling

  • As part of AEMP analysis, annual data, including under-ice WQ data (late-April ̶ mid-May), are compared to

SSWQO, modelled projections, and AEMP and operational monitoring data (ECCC R ECCC Reco comme mmenda dation 4.3b 4.3b)

  • A detailed comparison of AEMP data to modelled projections will be included in AEMP Re-evaluation report due to

MVLWB in 2019

  • De Beers will continue to collect detailed operational water quality monitoring data, which can be used

along with collected AEMP data, to validate WQ model predictions (ECCC R ECCC Reco commen mmendatio ion 4.3c 4.3c)

  • A WQ model update would only be completed if actual conditions identified an appreciable and consistent deviation from

projected concentrations

Area 8 Monit Area 8 Monitori ring

  • ECCC R

ECCC Reco commen mmendation 4. 4.1b 1b to include reporting of April AEMP Area 8 WQ results with SNP data presents some challenges to De Beers and the Board

  • Variability in timing of under-ice sampling and the subsequent laboratory reporting and data analysis and interpretation

provides uncertainty in how and when these AEMP results could be reported under the SNP reporting framework

  • De Beers will continue to report the under-ice water quality sampling results for Area 8 as part of the AEMP annual report

MONITORING

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17 The De Beers Group of Companies

  • AEMP water quality action levels will be

updated through the AEMP re-revaluation process (ECCC R ECCC Recommendation commendation 4.4a 4.4a)

  • 2019 AEMP Re-evaluation will account for revised

water quality model projections and updated

  • perational water management plan
  • In the event a water quality model update is

completed, revised projections will be evaluated and considered in reviews of the AEMP and Response Framework (ECCC ECCC Recommendation 4.4b commendation 4.4b)

RESPONSE FRAMEWORK AND ACTION LEVELS

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18 The De Beers Group of Companies

  • De Beers believes that comparing modelled air quality values near

the Mine to CAAQS is inappropriate (ECCC R CC Recommend commendation ation 4. 4.5)

  • AQ dispersion modelling is too conservative for realistic comparison
  • CAAQS designed to be compared to measured values in population

centres and whole airsheds, not at fencelines

  • Emissions changes at the Mine would not affect air quality in

Yellowknife

  • However, modelled predictions for PM2.5 and NO2 from the air

quality model update in the WL amendment application were presented in De Beers’ response for monitoring station locations to compare to CAAQS

  • De Beers will continue to monitor air quality at the Gahcho Kué

Mine as per the Air Quality and Emissions Monitoring and Management Plan

CANADIAN AMBIENT AIR QUALITY STANDARDS FOR NO2 AND PM2.5

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19 The De Beers Group of Companies

  • De Beers provided an update to the Offsetting Plan to

DFO based on the 2018 mine plan amendment

  • Consistent with DFO’s Policy and existing Fisheries Act

Authorization

  • De Beers will continue to consult with DFO on

quantification of habitat losses and gains from proposed offsetting measures to demonstrate that gains will counterbalance losses predicted to occur from the Mine’s activities (DF DFO R O Recommendation commendation 3. 3.1. 1.1)

  • The Final Offsetting Plan will include offsetting

measures as required by DFO to achieve equivalency

OFFSETTING PLAN UPDATE

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20 The De Beers Group of Companies

  • De Beers will provide additional information to DFO in a

Request for Review for the proposed closure diversion channel once further design details are available (DF DFO O Recommendation 3.2. commendation 3.2.1)

  • Lake D1 and Stream D1 already considered as losses in

the Authorization and Offsetting Plan

  • Closure diversion channel developed as a permanent

channel that will allow for fish movement between Kennady Lake and upstream locations in D watershed in post-closure

  • Expectation that Condition 4.1 of the Authorization will

continue to be met (i.e., allowing fish to migrate back into the lake and use the re-established habitats in Kennady Lake)

OFFSETTING PLAN UPDATE

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21 The De Beers Group of Companies

  • Mine plan amendment does not change volumes of water and timing

for flow mitigation

  • Monitoring of downstream Arctic Grayling population will continue as

per existing AEMP and approved Response Plan

  • Reporting to the MVLWB will continue under existing AEMP

mechanisms

  • As per the Response Plan, De Beers will conduct an assessment as

part of the 2018 AEMP to determine whether the current flow augmentation in the Downstream Flow Mitigation Plan is adequate (DF DFO R O Recomme commendations 3.3. dations 3.3.1 and 3.3.2 and 3.3.2)

  • De Beers will continue to engage with DFO through the MVLWB-

mandated AEMP and Response Plan processes, as well as directly for any potential implications to the Fisheries Act Authorization

DOWNSTREAM FLOW MITIGATION

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THANK YOU