Assessment of Water Management at Mining Sites in Nunavut

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Assessment of Water Management at Mining Sites in
Nunavut
A presentation in YellowknifeAnnual Geoscience
Forum
By Li Wan
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Outline of the Presentation

• Introduction
• Mining Impacts to Surface Water and Ground Water
• Elements of Mining Water Management
• Water Quality Monitoring
• Concerns during NIRBs Screening/Review of
  Project Proposals

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The Purpose of Water Management Systems in
Mining

• The purpose of water management during mining
  operations is to eliminate and/or limit the
  adverse effects of mining operations on the
  regional hydrological regime and to ensure that
  local hydrologic conditions do not jeopardize
  mining operations.

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Adverse Impacts in Mining Area by Mining
Operations

• Quantitative Impacts

• Changes in water body levels
• Changes in lake and river currents
• Changes in water flows regime
• Channeling and shoreline erosion
• Underground mine inflows
• Increased runoff volumes

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Adverse Impacts in Mining Area by Mining
Operations

• Qualitative Impacts

• Tailing effluent and spills
• Dust from blasting, construction activities (silt
  runoff)
• Lake sediment disturbance during rock placement
• Sedimentation from permafrost degradation
• Acidic leaching of metals
• Release of contaminated pore water from tailings
  during freezing
• Seepage of tailing water into groundwater ( via
  talik zones under tailing impoundment facilities)

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Adverse Impacts in Mining Area by Mining
Operations

• Competitive impacts

• Changes in natural surface drain patterns
• Deterioration of water quality
• Degradation of landscapes and aesthetic values

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Sources of Pollutants at Mine Site

• Geochemical Reactions (PAG)

• Oxidation of pyretic material in iron and
  metalliferous ores that generate sulphuric acid
  or acid mine drainage.

• Metals Leaching (ML)

Metal leaching from various rock sources
including quarried fill rock for infrastructure
construction, temporary ore stockpiles and waste
rock stockpiles.
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Sources of Pollutants at Mine Site

• Blasting residues

Explosive residue ammonia and nitrate

• Contaminated precipitation runoffs

Rain water and snowmelt collected within in fuel
transfer stations, tank farms, land farm
facilities, non-hazardous landfill sites etc.

• Mill tailing

• Sewage plant effluent

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Sources of Pollutants at Mine Site

• Suspended matter

Released to water bodies from shoreline
erosion and re-suspension by wave action in lakes.

• Salinity

Released from drilling fluids.

• Hazard materials

Spilled petroleum products, additives and
reagents, waste oils, greases, battery liquids,
laboratory wastes etc.
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Water Management Tools

• Water Balance

A mine site water balance is a tool used to
assess amounts of water entering, leaving and
moving across the mine site. It incorporates

• Precipitation
• Evaporation
• Infiltration/Percolation
• Surface runoff
• Inflows and outflows of a specific catchment area

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Water Management Tools
Scheme of a Typical Water Balance
Catchments balance Boundary
Evaporation
Snow
Rain
Ground evaporation/filtration
Tailing impoundment facility
Lake precipitation
Ground precipitation
Decantant treatment (optional)
Effluent
Tailing slurry
Under ground mine water
Residual precipitation
Clear runoff
Fresh Water
Mill
Contaminated areas
Sewage plant
polluted runoff
Camp
Treated discharges
Seepages
Tailing impoundment balance boundary
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Water Management Tools

• Water quality Modelling

A model simulates the various water
interaction processes on the mine site. Modelling
can predict water discharge quantity and quality
from the mine site. This modelling process is
based on following data

• Baseline hydrological and hydrogeological data
• Mill effluents lab tests/analysis data
• Regulation discharge criteria
• Scientific assumptions
• Water balance data

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Water Management Tools
Flow Diagram of a Water Quality Modelling
Model input
Model output
Model modification
Engineering improvement
Tailing impoundment modeling
Tailing pond conditions
Water quality monitoring
No
Baseline data
Level control
Scientific assumptions
Meet standards
Discharge strategy
Mill effluents
Treatment options
Polluted runoff flows
Yes
Regulatory limits
Control parameters
Discharge
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Water Quality Monitoring

• Federal Guidelines and Regulations for Discharges

1. CCME guidelines for the protection of aquatic
life within fresh waters
Issued by Council of the Ministers of the
Environment. The Guidelines represent a vigorous
determination of levels for a suite of parameters
that are protective of aquatic life within fresh
waters in Canada.
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Elements of CCME Water Quality Guidelines for
the protection of aquatic life within fresh
waters
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Water Quality Monitoring

• 2. MMER Regulations under Fisheries Act

MMLER (1977) Metal Mining Liquid Effluent
Regulations
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Parameters to be Controlled and Measured for
Water Quality under MMER
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Water Quality Monitoring
3. Other Federal Guidelines and Legislation

• Nunavut Waters and Surface Rights Tribunal Act

• Nunavut Land Claim Agreement Act

• Arctic Waters Pollution Prevention Act and
  Regulations

• Canadian Drinking Water Guidelines

• Freshwater Intake End-of-Pipe Fish Screen
  Guidelines - DFO

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Water Quality Monitoring

• The Territorial Guidelines and Regulations for
  Discharges

• Guidelines for the Discharge of Domestic
  Wastewater in Nunavut

• Environmental Guidelines for Industrial Waste
  Discharges

• Spill Contingency Planning and Reporting
  Regulations and etc.

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Water Quality Monitoring

• Nunavut Water Board Terms/Conditions

• For the discharges, which the Federal and
  Territorial regulations do not apply with, the
  Nunavut Water Board may provide discharge
  standards in a related water license. This is
  usually in relation to small volume discharges in
  remote areas.

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Concerns in Screening and Review of Project
Proposal

• Water Management Tools

• Water Balance
• The completeness of identification of water and
  wastewater sources.
• Components of Surface water, ground water and
  deep ground water studies and identification of
  such (permafrost, taliks).
• Water movement fashions among different exists
  water bodies and associated flow (conductivity)
  rates.
• Waste generating sources and migration paths and
  associated waste water quality and quantity.
• All potential PAG and ML generating sources.

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Concerns in Screening and Review of Project
Proposal

• Water Management Tools

• Water Quality Model
• The identification control parameters in
  discharge.
• Estimations and assumptions in case baseline data
  are unavailable.
• Management and adaptive plans for scenarios of
  extreme conditions (drought and wet conditions)

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Concerns in Screening and Review of Project
Proposal

• The process management plans

• The completeness of required management plans
  directly and indirectly related to mine site
  water quality
• Adopted regulatory discharge limits
• Federal guidelines, acts and regulations.
• Territorial guidelines, acts and regulations.
• Nunavut Water Board standards (small volume
  discharge in remote areas)

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Concerns in Screening and Review of Project
Proposal

• Project Planning and Design

• The Dams
• Core frozen monitoring methods and leakage
  monitoring
• Contaminated water collection sumps and
  diversions
• Treatment and discharge standards
• Sewage treatment plant
• Emergency Measures and discharge criteria.
• Chemical treatment facilities ( polishing ponds)
  
• Metals to be removed , methods, and operating
  conditions, especially sequential PH control
  methods

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Concerns in Screening and Review of Project
Proposal

• Project Planning and Design

• Landfill and landfarm facilities
• Capacities and surface drain patterns
• Berms /ditches
• Flooding management and seepage.
• Water intake/discharge facilities
• aquatic habitat protection measures
• The aquatic habitat enhancement
• location, construction time windows

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Thank you !
Any Questions ?