Kemess North

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Kemess North

• Supplementary
• Alternatives Workshop

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Workshop Purpose
Communicate the alternatives available and assess
alternatives together. To get federal and
provincial agency agreement that Kemess North
waste rock and tailings is PAG and best
management practices for ARD prevention is
sub-aqueous disposal. To confirm the final
alternative(s) and agree on the review process
for the environmental assessment.
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Alternatives Assessment to Date

• October 2003 - Project Description Submitted
• November 2003 First Agency Meeting
• December 2003 Pre-feasibility Alternatives
  Assessment Submitted
• January 2004 Stakeholders Alternatives Meeting
• February March 2004 Feedback and Reassessment
• March 2004 Supplementary Alternatives Report
• April 2004 Agency Alternatives Workshop

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Alternatives PresentationAgenda

• General requirements
• Description of all alternatives
• Summary of main alternatives and combinations of
  alternatives
• Comparison of alternatives (cost and risk)
• Environmental comparison of alternatives

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CEAA Alternative Assessment Requirements

• What is the project need and purpose?
• What are the alternative means of carrying out
  the project?
• What are the alternatives to the project?

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Project Need and Purpose

• Purpose - To produce copper/gold concentrate in
  an environmentally responsible manner that
  returns an economic benefit to the company.

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Alternative Means of Carrying Out the Project

• Mining Methods Underground mining is too
  expensive for the ore grades.
• Plant Optimization Milling will be increased to
  meet the economic requirements of the deposit.
• Waste Management Options Typical of mining,
  waste management alternatives are a critical
  project component.

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Engineering Guidelines for Alternatives

• 320 Mt (previously 250 Mt) of potentially acid
  generating tailings
• 200 Mt (previously 375 Mt) of potentially acid
  generating waste rock
• 75 to 90 of waste rock will be acid generating
  if not kept submerged under water.
• Minimize number of sites.
• Minimize heights and complexities of dams.
• Minimize water management, particularly on
  closure.

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Environmental Guidelines for Alternatives

• Minimize footprint.
• Minimize aquatic and terrestrial impacts.
• Minimize metal leaching and ARD.
• Minimize long term closure risk.
• Sustainability. (Sustainable Development defined
  as development that meets the needs of the
  present, without compromising the ability of
  future generations to meet their own needs.)
  continuation of economic benefits

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ARD Prevention Industry Accepted Methods

• Provincial ARD Guidelines the storage location
  must remain permanently flooded and
  geotechnically stable.
• Natural Resources Canada and MEND The target
  is for new mines to open without long-term
  concerns about acidic drainage upon closure.

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Underwater Facilities
Elliot Lake area tailings
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Underwater Facilities
Equity Silver Tailings Pond
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Underwater Facilities
Eskay Creek Waste Rock Disposal Albino Lake and
Tom MacKay Lake
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Underwater Facilities
Musselwhite, Ontario
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Flooded and Reclaimed Site
Dennison Mine Elliot Lake, ON
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Other Mines Affecting Lakes
Diavik
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Other Mines Affecting Lakes
Ekati
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Underwater Facilities and Research
Louvicourt Tailings Pond
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ARD Control Covers Treatment

• Equity Silver
• Low permeability glacial till cover. Marginal
  improvement in ARD control.
• Cover concerns with
• Freeze-thaw
• Plants (roots) animals
• Alternative groundwater paths
• Erosion
• Cover can minimize seepage but rarely provides an
  oxygen barrier to limit ARD.
• Water Treatment Plant likely hundreds of years
  of liability.

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Waste Quantities Comparison (source Minfile)

• Bell Copper 70 Mt PAG tailings
• Huckleberry 36 Mt PAG tailings
• Equity Silver 33 Mt PAG tailings
• Kemess South 89 current, 200 Mt expected PAG
  tailings
• Kemess North need to dispose of gt300 Mt PAG
  tailings and gt200 Mt PAG waste rock

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Alternative Identification

• Considered all sites within about a 10 km radius
  that could store some or all of the waste.
• Integrate/consider technology variations.
• Considered combinations of alternatives.

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Screened TechnologiesTailings

• Thickening paste reduced volume, however still
  requires a dam and saturation of sulphides.
• Dewatered reduced volume dry stack, however
  still need to compact dam support zone. ARD
  from partially saturated tailings.
• Co-disposal with waste rock Only a portion of
  the tailings could be mixed. Concerns with
  mixing, and ARD from the final mixed product.
• Desulphidize Tailings Used to produce
  construction sand from cycloned tailings. Can be
  used for capping.

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Screened TechnologiesARD Control

• Saturate under water Preferred ARD control
  method. Base consideration for this project.
• Cover Poor success rate (e.g. Equity Silver
  Mine) concern with long term integrity of cover
  and potential for alternative seepage paths.
• Water Treatment Concerns with long term
  operation, maintenance of facility (hundreds of
  years) and sludge disposal. Need disposal site
  for sludge.
• Limestone mixing Limited ability of lime to
  properly mix and balance ARD.

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Screening Process

1. Layouts and cost estimates for all alternatives.
2. Risk Assessment using Failure Modes Effects
   Analysis (FMEA) procedures which are recommended
   by the Mining Association of Canada and adopted
   by numerous Regulatory Authorities in Canada and
   USA.
3. Environmental Comparison, including compensation
   potential.

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Location Plan of Selected Screening Sites

• Tailing Alternatives (330 Mt)
• Raise existing tailings dam
• Infill existing open pit (25 of tailings)
• Raise open pit
• Sites L M (close to Kemess South Mine)
• Site C and Kemess Lake
• Duncan Lake (25 of tailings)
• Waste Rock Alternatives (250 Mt)
• North Northeast Dumps
• Site C
• Duncan Lake (50 of waste rock)

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Screened LocationsExisting Tailings Facility

• Project Components
• Dam raise from 145 m to 170 m
• high.
• Pumping head 310 m
• New water diversion dams and
• diversion canals/pipelines.
• Continue to use de-sulphidized
• cycloned sand for construction of dam.
• Cost 400 million

• Advantages Disadvantages
• Stores tailings only.
• Limited new disturbance.
• Dam safety risk due to very low foundation shear
  strength. Slopes 5.5H1V
• Toe of dam encroaches on Mill Creek.
• High pumping head.

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Screened LocationsOpen Pit - Tailings

• Advantages Disadvantages
• Stores tailings only (max. 250 Mt)
• Limited new disturbance.
• Dam safety risk with 100 m high dam above the
  plantsite.
• Toe of dam encroaches on Kemess Creek.

• Project Components
• Construct 100 m high dam around
• the open pit.
• Use de-sulphidized cycloned sand
• for dam construction.
• Pumping head 120 m.
• Some potential for weak clay layers in the dam
  foundation.
• Cost 200 million

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Screened LocationsSite L - Tailings

• Advantages Disadvantages
• Stores tailings only ( 250 Mt )
• Limited new disturbance.
• Very poor storage/dam ratio due to presence of
  mine waste rock and topograhy.

• Project Components
• Construct 100 m high dam in the vicinity of the
  existing waste dump.
• Use de-sulphidized cycloned sand
• for dam construction.
• Pumping head 120 m.
• Potential for weak clay layers in dam foundation.
• Cost 785 million

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Screened LocationsSite M - Tailings

• Advantages Disadvantages
• Stores tailings only (max. 250 Mt )
• Disturbance of terrestrial/forested areas and
  wetland.
• Poor storage/dam ratio due to topograhy.

• Project Components
• Construct 100 m high dam in the vicinity of the
  existing airport and power line.
• Use de-sulphidized cycloned sand
• for dam construction.
• Pumping head 120 m.
• Potential for weak clay layers in dam foundation.
• Cost 440 million

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Screened LocationsSite F - Kemess Lake -
Tailings

• Advantages Disadvantages
• Infills Kemess Lake.
• Stores tailings only (max. 250 Mt)
• Disturbance of terrestrial/forested areas and
  wetland.
• Very difficult geotechnical conditions.

• Project Components
• Construct 150 m high dam across south end of
  Kemess Lake.
• Use de-sulphidized cycloned sand
• for dam construction.
• Pumping head 170 m.
• Weak foundation.
• Unstable bedrock geology in left bank of
  impoundment.
• Cost 335 million

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Screened LocationsSite C - Tailings/Waste Rock

• Advantages Disadvantages
• Could be raised 70 m to store mine waste rock.
• Disturbance of terrestrial/forested areas and
  wetland. Significant wildlife corridor.
• Long haul distance for mine waste rock and high
  pumping heads for tailings.

• Project Components
• Construct two 100 m high dam
• Use de-sulphidized cycloned sand
• for dam construction.
• Pumping head 260 m.
• Cost 260 million tailings
• 775 million waste rock/tailings

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Screened LocationsDuncan Lake - Tailings and
Waste Rock

• Advantages Disadvantages
• Loss of Duncan Lake habitat.
• Sustainable allows for future use of regional
  resources.
• Most efficient site.

• Project Components
• Construct one 80 m high dam and two 20 m high
  dams to store all tailings and waste rock.
• Pumping head 160 m.
• Cost 60 million tailings, 140 million waste
  rock/tailings

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Screened LocationsAttycelley - Tailings and
Waste Rock

• Advantages Disadvantages
• Loss of Attycelley stream habitat.
• Impact on terrestrial and wildlife corridor.
• Difficult geotechnical conditions and difficult
  seepage control.
• Large watershed increase closure water control
  risk.

• Project Components
• Construct 100 m high starter dam, raise to 160 m
  high.
• Pumping head 200 m.
• Foundation conditions expected to be complex.
• Dam use de-sulpidized cycloned sand.
• Cost 625 million waste rock/tailings

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Screened LocationsNE Cirque Waste Rock

• Advantages Disadvantages
• Geotechnical risk of water dam.
• Long term risk of ARD from cover and treatment
  alternatives.
• Lowest haulage cost.
• Limited disturbance of terrestrial environment.

• Project Components
• 200 m high waste rock pile
• ARD controlled by
• Water dam at downstream toe.
• Low permeability covers.
• Water treatment and sludge disposal.
• Costs 125 million

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Alternatives for Both Tailings and Waste Rock

• Supplementary Alternatives
• Upper Attycelley
• Open Pit/TSF/Site M
• Duncan Lake
• Alternative Assessment
• Site C
• On-land dump w/treatment, open pit/TSF

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Alternatives Summary of Risk Points
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Comparison of Alternatives Risk and Cost
ALTERNATIVE Risk Points Cost Million
Attycelley Creek 735 625
Open pit/Site M/TSF 678 995
Duncan Lake 417 135
Site C 1,317 775
Open pit/TSF/NE Dump with treatment 1,401 325
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Environmental ComparisonCriteria

• Aquatic effects
• Terrestrial effects
• Footprint of disturbance
• ARD prevention
• Contaminant control
• Dam stability

• Closure
• Sustainability
• Cost
• Risk
• Ability to compensate and mitigate

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Environmental Comparison
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Kemess North Area
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Kemess North Post Closure
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Alternatives to the Project

• 1. No Kemess North Project
• 2. Develop Kemess North Project
• Developing Kemess North maximizes the use of the
  resources and infrastructure that already exist.
• Northgate has a responsibility to exploit the
  resource in an environmentally safe and
  profitable manner.

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Path Forward
Underwater Disposal of Potentially Acid
Generating Waste Alternative(s) Update
Environmental Comparison of Main
Alternatives Review Process
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Geologic Cross-Section