Sessions Introduction September 14, 2011 De Beers in Canada - - PowerPoint PPT Presentation

Technical Sessions Introduction

September 14, 2011

De Beers in Canada

Years Milestone 1961 to present

• Exploration for diamond deposits

2000

• De Beers acquires Winspear Diamonds and Snap Lake Deposit

2004

• Environmental Agreement for Snap Lake Mine
• Snap Lake Mine receives EA approval, licenses and permits to

build and operate 2005

• Construction begins at Snap Lake Mine
• EA for Victor Mine approved and construction of that mine begins

2008

• Snap Lake and Victor Mines commence operations
• Global recession

2009

• Global recession continues
• Reduction in production and staffing levels at Snap Lake

2010

• Production ramp-up at Snap Lake and increase in staffing
• Initiation of work streams required for renewal of water license

2

Sustainable Development

• Purpose: To produce diamonds safely and profitably –

without harm to people or the environment – Care and respect for the environment, employees and communities – Benefits: employees, communities, businesses – Effective management systems; continuous improvement – Compliance with legal requirements and De Beers policies and standards

3

Mine Plan Considerations

• Mine plan is reviewed annually
• Factors affecting mine plan:

– Grade – Dilution – Recovery – Cost of production – Diamond prices

• Current Life of Mine is 2030 based on 2011 optimization

study

• Material changes in mine plan will be reflected in future

updates to hydro-geological modelling

4

Snap Lake Status – Good News

• The mine has not had adverse impacts on Snap Lake

based on: The Aquatic Effects Monitoring Program (AEMP)

• All measured parameters have been, and are

predicted to be, below water quality limits or other thresholds with three possible exceptions – TDS (total dissolved solids), fluoride, manganese

5

Effluent Pipe and Diffuser Replaced

Minimal foreshore disturbance Diffuser velocity measured

6

Requested New Water License

• Changes requested:

– 15 year term of license – Change “project” to “mine” for clarity and consistency – Change of title of Ore Storage, Waste Rock, Processed Kimberlite Management Plan (OSWRPKMP) to North Pile Management Plan – Clarification of “major storm event” to inform monitoring – Combine waste and water management plans into one part of water license (separate subsections)

• Fewer documents to be reviewed and submitted

annually

7

Requested New Water License (cont’d)

Changes requested (cont’d):

• Removal of posting security requirement for Starter

and East cells – Both securities are currently held

• Annual engineer inspection of all waste containment

facilities and runoff control structures to be submitted 60 days post inspection

8

Snap Lake Mine – Status and Future

Demobilization of temporary camp winter 2012 Sewage Treatment Plant: Being relocated to accommodate new accommodation complex Total Dissolved Solids (TDS) Currently De Beers is carrying out TDS toxicity studies to determine an effects threshold:

• Phase 1 involved work with chironomids
• Phase 2 involves work with zooplankton/plankton
• Phase 3 will involve work with fish based on toxicology

work conducted at University of Guelph Conditions within the water license can be changed through a Water Board Hearing without a full water license renewal

9

Snap Lake Mine – Status and Future (cont’d)

North Pile

• Surface distribution system installation is currently on track

– Installed and tied into the Starter Cell – Upgraded thickener pumps installed in Process Plant for increased density of PK – Current stand-by PK line will remain in place as back-up

• Surface depositional trial commences end of September
• Deposition of paste to North Pile targeted to commence in

Q1 2012 assuming trial successful

• East cell construction occurring in phases as deposition

locations are required

• North pile capping research in progress

10

Reclamation and Closure

ICRP

• 2006 – De Beers produced the first Interim Closure and

Reclamation Plan (ICRP) for the Snap Lake Mine – Document Approved by the MVLWB

• 2011 – The 2006 ICRP was updated and submitted to the

MVLWB as part of the WL application; the 2011 ICRP included:

– Updated goals and objectives for closure and reclamation – Refined predictions for closure conditions – Updated research program to address uncertainties and concerns – Updated schedule for progressive reclamation of the North Pile – Updated Gantt chart with estimated schedule for closure and reclamation of all mine elements

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Reclamation and Closure (cont’d)

Progressive Reclamation (2011 ICRP)

• The North Pile will be progressively reclaimed as follows:
• Starter Cell: 2012 – 2014
• East Cell: 2014 – 2019
• West Cell: 2024 – 2029
• 2030 – Final Closure

Final Closure and Reclamation Activities

• Mine activities will cease in 2029
• The closure and reclamation of the Snap Lake mine will

initiate in 2030 with mobilization of equipment on the 2029/2030 winter road

12

Reclamation and Closure (cont’d)

Closure of Mine Elements

Main Snap Lake Mine Features

North Pile Underground Mine Water Management Structures Process Facilities and Surface Infrastructure Crushed Rock/Ore and Concrete Facilities Roadways and Airstrip Solid Waste Facilities

Disposal Facility within North Pile Landfarm within North Pile area Camp Facilities Laydown Area Process Facilities and Related Infrastructure Mine Offices, Mine Dry and Maintenance Shops General Utilities Building Underground Heating Plant Crushed Rock/Ore Storage Facilities Construction Shops - Warehouses Fresh Water Intake and Pumphouse Fuel Storage Facilities Powder Magazines Site Roads, Culverts and Ditches Airstrip and Related Facilities Processed Kimberlite (PK) Water Management Pond (WMP) Pipelines Treatment Plants

Mine Water Sewage Water

Transfer Storage Area Rock Quarries Paste Backfill Non-Hazardous Wastes Hazardous Wastes and Magazines PAG Waste Rock Seepage and Sumps Diversion Ditches Mine Water (Collection and Removal) Cover

Fresh Water

Diversion Ditches and Site Hydrology Power Facilities and Related Infrastructure Paste Backfill Facilities Crusher and Related Facilities Winter Access Road Mobile Equipment Incinerator and Related Facilities Underground Workings Concrete Facilities

13

Reclamation Research Plans

• North Pile
• Vegetation of the North Pile Cover
• Process Kimberlite (PK) Storage Facility (to assess

PK strength parameters)

• Dust Control
• North Pile Cover
• North Pile Cryoconcentration
• Seepage (Hydrology)
• Monitoring of Temperature
• Stability and Deformation
• Refinement of Predictions and Assumptions

Reclamation and Closure (cont’d)

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Reclamation Research Plans (cont’d)

• Water Management Structures
• Mine Water Properties
• Seepage from North Pile
• Process Facilities and Surface Infrastructure
• Refinement of Predictions and Assumptions
• Re-vegetation of Disturbed Areas

Reclamation and Closure (cont’d)

15

Financial Security (final determination by Board)

• De Beers and AANDC have discussed financial security for

the Snap Lake mine and have exchanged information

• De Beers and AANDC continue to work together towards

the development of a financial security estimate that captures the “total liability associated with permanent closure, including any costs associated with progressive reclamation and temporary closure”

(Source: MVLWB 2009 DRAFT Closure and Reclamation Plans – Preparation Guidelines for Mines within the Mackenzie Valley)

Reclamation and Closure (cont’d)

16

Annual Mine Reclamation Status Report

• De Beers submits the following two documents to the

MVLWB on an annual basis:

• Annual Report by March 31 (Part B#5 (a) to (v))
• Annual Mine Reclamation Status Report by March 1

(Part I#8)

• De Beers recommends the following change:
• Inclusion of the Annual Mine Reclamation Status Report

into the Annual Report for submission to the MVLWB by March 31

Reclamation and Closure (cont’d)

17

Water Quantity

Hydrology

• EA predicted small increases in the water elevation of Snap

Lake over the life of the mine (3.3 to 5.3 cm)

• In 2010 water elevation in Snap Lake and other nearby

lakes decreased approx 16 cm due to low precipitation and high evaporation

• Changes in Snap Lake water elevation are consistent with

nearby lakes, primarily influenced by atmospheric conditions – not the mine

• Natural variability is greater than EA predictions
• Natural variability could potentially affect quantity of fish

and/or their food available from shoreline and downstream areas (loss of habitat, temperature changes)

18

Predicted Future Water Quality

• Throughout mine life all parameters except TDS, fluoride and

manganese1 are predicted to remain below applicable water license thresholds / benchmarks

• Between 2018 (upper bound case) and 2023 (lower bound)

TDS predicted to exceed Water License Limit (whole lake average)

• Fluoride concentrations will be below the interim CCME water

quality guideline by 2016

• Nitrate and ammonia will be lower than predicted by EA –

benchmarks have changed since the EA (will be discussed under EQC)

• Model will be re-run in 2012/2013 based on new data

1Manganese was measured not modeled

19

TDS – Modelling Results

20

Monitoring Results to Date

Water Quality

• As predicted in the EA water quality is changing
• Only 2 parameters above water quality guidelines to date:

– fluoride (approx. ½ of the data above interim aquatic guideline) – manganese (4 of 134 samples collected above aesthetic drinking water guideline)

• Investigative Studies 2011:

– field study near historic explosives storage pad: not a clear, dominant source of ammonia to lake; ammonia concentrations in Snap Lake low compared to water quality guidelines – sampling of downstream lakes to: estimate spatial extent of mine- related effects downstream of Snap Lake; aid in selection of future downstream AEMP stations; and, obtain data to compare/validate existing downstream lake water quality model

21

Monitoring Results to Date (cont’d)

Plankton communities have changed since baseline:

• Phytoplankton:

– biomass increased in Snap Lake 2004-2009 then decreased in 2010 – shift from Cyanobacteria-Chrysophycea co-dominance to diatom dominance

• Zooplankton:

– no clear trends in overall biomass – calanoid copepods were dominant taxa pre-mine, decreased biomass since 2006 – all species of rotifers have appeared and disappeared – no clear trend related to effluent discharge

• Changes due to nutrient enrichment were predicted in EA

22

Monitoring Results to Date (cont’d)

Sediment Quality

• Naturally elevated concentrations of some metals (e.g.,

cadmium, chromium, copper, zinc) in sediments

• No trend in elevated sediment metals, nutrients or other

measured substances due to the Mine except available phosphate near diffuser

• Investigative Study 2011: to assess feasibility of shallower

sediment sampling

• Investigative Study 2012: to investigate potential impact of

surface runoff on Snap Lake sediment quality

23

Monitoring Results to Date (cont’d)

Sediment Invertebrates

• Nutrient enrichment in Near-field and Mid-field (increased

total densities) – predicted in EA

• Possible TDS enrichment: higher Mollusca densities –

predicted in EA

• Investigative Study 2011: comparison of 250 and 500 µm

mesh sieves at a sub-set of stations to address comment in 2009 AEMP that using a 500 µm sieve in the field may result in loss of small Chironomidae (midges) that are a dominant part of the benthic community in Snap Lake

24

Monitoring Results to Date (cont’d)

Fish

• No changes in fish community composition
• More fish captured in Snap Lake than reference (Northeast

Lake)

• Fish age and growth similar between the 2 lakes
• Fish tissue concentrations of contaminants of concern have

not increased over time in large fish

• Fish are old; lake chub are older than the reported

maximum in literature

25

Monitoring Results to Date (cont’d)

Fish (cont’d)

• Small bodied fish under-ice survey performed

February/March 2011: baited minnow traps with various attractants/food not successful method for capturing slimy sculpin in Snap Lake in spring / under ice conditions

• External Workshop scheduled for Q1 2012:

– review of monitoring program design (monitoring should not put fish stocks at risk) – develop an appropriate monitoring response for fish that will link the AEMP with adaptive management

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Thanks for Listening