golden giant mine closure - bc...

GOLDEN GIANTMINE

Golden Giant Mine Closure

GOLDEN GIANTMINE

Contributions and Achievements

614

Golden GiantMine

• Production life…from 1985 to 2006• Initial Capital Expenditure $C290 million

• First Blade to First Gold Brick in 2 years

• Total of 19.1 million tonnes of Ore Milled

• Average Gold Head Grade 11 grams/tonne

• Total Gold Sold 6.7 million ounces

• Total Gold Revenue $C3.2 billion

• Total Costs/Expenditures $C1.9 billion

• Total Corp/Mining Taxes $C660 million

• Total Labour Costs $C440 million

• Total Local Taxes $C23.8 million

• Local Charitable Donations over $C1.5 million

• Employed over 1500 plus 650 for construction

GOLDEN GIANTMINE

Closure - Points of Interest

• Staged layoffs (over 250) in 2005/2006

• Last ore hoisted Jan 11th 2006

• Site became inactive Aug 31st 2006 (<5 employees)

• Deconstruction/demolition – completed by Sep 2010

• done by asset purchaser• 200+ trucks of equipment & 3 M kg scrap metal

• Reclamation/restoration – completion by ~2015

• done by property purchaser• Mill gold salvage - in house and contractor

• 71,325 oz !!! recovered by Q4 2007• Asset sales - buildings, s/u equipment, mine property

• $6.659 Million plus royalties

GOLDEN GIANTMINE

Closure Plan Overview

• Closure Plan Objectives– Public health and safety– Minimizing environmental impacts and– Rehabilitation of the site to a compatible land use

• Original Closure Plan accepted by MNDM April 1997– Several updates for addition of WWTP, PSA, GCS– Reviewed by MOE, MNR, MOL, MNDM and local COI (28 copies)– Includes financial assurance of $C14.7 Million

• Primary Focus Now – Managing the Interlake Tailings Facility & WWTP

GOLDEN GIANTMINE

Interlake Tailings Facility

GOLDEN GIANTMINE


• $50 Million for 4 Dams, grouting, HDPE 80mil liner, clay core top

• 15.3 M tonnes of tailings deposited under water cover

• 1984 - GCP trench intercept system for main Dam 41

• Capturing 95% of Dam 41 seepages since 1985 • 2014 - GCS for Dam 43/Dam 44 interceptor pump wells

• needed to mitigate sulphate in headwater creeks• Capture ~87% of Dam 43/44 seepages• $3.0 Million for new GCS - commissioning mid 2014• Target is <50 ppm sulphate for aquatic protection

• Overall seepage capture for ITF becomes 93%

• WWTP treats all ITF excess water - discharge to Cedar Creek

GOLDEN GIANTMINE


• Tailings acid generating potential and ARD seepages

– Sulphide 4.5% with little NP, NP/AP <0.3 and NNP -140 ppt

– Mo 1100, Ti 700, As 200, Sb 150, V 90, Zn 80, Hg 12 ppm

• Dam 42 and Dam 44 wells not showing ARD Fe < 0.2 ppm

• Dam 43, Dam 44 and Dam 41 wells showing ARD Fe>10 ppm

• High sulphate showing in all seepage/wells at Dam toes

• Confounding factor – pyrite deposit across ITF – west to east

• Pyrite highly fractured seams may be source of ARD Fe

GOLDEN GIANTMINE


Reclaim Water

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

1996

1995

1994

1993

1992

1991

1990

1989

1988

1987

1986

1985

mg/

L

50

45

40

35

30

25

20

15

10

5

0

Cyanide, TotalMolybdenum, TotalAntimony, Total

GOLDEN GIANTMINE


Reclaim Water

2013

2012

2011

2010

2009

mg/

L

1.00

0.90

0.80

0.70

0.60

0.50

0.40

0.30

0.20

0.10

0.00


Reclaim Water

2013

2012

2011

2010

2009

mg/

L

1.00

0.90

0.80

0.70

0.60

0.50

0.40

0.30

0.20

0.10

0.00


Reclaim Water

2013

2012

2011

2010

2009

mg/

L

1.00

0.90

0.80

0.70

0.60

0.50

0.40

0.30

0.20

0.10

0.00


Reclaim Water

2013

2012

2011

2010

2009

mg/

L

1.00

0.90

0.80

0.70

0.60

0.50

0.40

0.30

0.20

0.10

0.00


GOLDEN GIANTMINE


Reclaim Water

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

Sulp

hate

, Tot

al (

mg/

L)

2000

1750

1500

1250

1000

750

500

250

0

GOLDEN GIANTMINE

Interlake Tailings Facility – 2005 Schematic

Luigi’s Watershed Cedar Creek

ET Plant

Tailings BasinWater Diversion Dyke

Lim Lake

Seepage

Open Channel Flow

Pipeline Flow

Legend:

Mine/Mill/Plant Site

Recycle WaterMill

Tailings

GCP Facility

Black River tributaries

GOLDEN GIANTMINE


Luigi’s Watershed


Seepage

Open Channel Flow

Pipeline Flow

Legend:

Cedar CreekGCP Facility


GOLDEN GIANTMINE



Luigi’s Watershed


GCP Facility

Seepage

Open Channel Flow

Pipeline Flow

Legend:

Cedar Creek

WWTP Facility

GOLDEN GIANTMINE



Luigi’s Watershed


GCP Facility

Seepage

Open Channel Flow

Pipeline Flow

Legend:

Cedar Creek

WWTP Facility

GCS D44

GOLDEN GIANTMINE



Luigi’s Watershed


GCP Facility

Seepage

Open Channel Flow

Pipeline Flow

Legend:

Cedar Creek

EW Facility

GCS D44

GOLDEN GIANTMINE

Dam 41 - Closure + 00 Years

Particle Track ModellingCondition: Tailings Pond Water and Pore Water Contaminated

GOLDEN GIANTMINE


Particle Track ModellingCondition: Tailings Pond Water Clean and Pore Water Near Dam Flushing

GOLDEN GIANTMINE


Particle Track ModellingCondition: Tailings Pond Water Clean and Pore Water Near Dam Flushed Out

GOLDEN GIANTMINE

Waste Water Treatment Plant

• Design/build by WESA for $7.8 M with PLC/SCADA System

• Building done in 2008, construction from Feb to May 2009

• Commissioned Jun 8th 2009, minor upgrades over 2 years

• Design Basis: meet I/PWQO = CWQG at end of pipe

• Design Flow: 91 m3/hr in, 80 m3/hr out (backwash/sludge 11)

• Effluent limits (receiver based) - 100% compliance to date

• Effluent objectives at end of pipe - very close since Nov 2011

• Operating costs levelling off after 3 years

– Target is $500,000/yr for 450,000 m3

– Or $1.10/m3 (operators, power, chemicals, maintenance)• Testing Xogen process add-on for NH3, NO3

-1, CN-1 removal

GOLDEN GIANTMINE

WWTP Process Flow Sheet

Caustic Circuit Acid Circuit MMedia Filtration Ion Exchange EQTank

NaOH

Ferric

Polymer

Clarifier

Ferric

HCl

Polymer

Clarifier

Graded

Gravel

Sand

Anthracite

GOLDEN GIANTMINE

WWTP Effluent Water Quality

WWTP Effluent

2013

2012

2011

2010

2009

mg/

L

0.36

0.34

0.32

0.30

0.28

0.26

0.24

0.22

0.20

0.18

0.16

0.14

0.12

0.10

0.08

0.06

0.04

0.02

0.00

Molybdenum, TotalAntimony, TotalCofA Monthly Average Objectives - WWTP Effluent 2009+CofA Monthly Average Objectives - WWTP Effluent 2009+

GOLDEN GIANTMINE

Closing Remarks

• Long Term Monitoring Programs

• Remain under Federal MMER and MNDM/MOE requirements

• Current monitoring program will continue indefinitely

• Any modifications to the program requires Ministry approval

• Plan to reduce number of sampling stations (90) and parameters (35) once acceptable track record is achieved

• 20 year “rolling window all in costs” projected at $1.5 M/yr

• WWTP operation, EEM program, tailings dam inspections, all water monitoring programs, reporting with 4 employees

GOLDEN GIANTMINE

Golden Giant Mine ClosurePre-Closure Tailings Pond

GOLDEN GIANTMINE

Golden Giant Mine ClosureClose-Out Tailings Pond

GOLDEN GIANTMINE

QUESTIONS

Contact Information Alternate Information

Walter Sencza, P.Eng. Walleye Sencza, pHD3

Environmental Manager Jack of all Trades

Newmont Canada Corporation We Do Inc (mostly)

[email protected] [email protected]

Tel: 807-238-2108 Cell: 807-229-6087

golden giant mine closure - bc...

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