clermont coal mine project

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    ermont oa ne ro ect

    Selection of Tailings Paste Thickenerus ec n ca eet ng

    17 February 2010

    Norris September / Rebecca Kirkwood

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    Topics

    > Metallurgical Design Considerations

    > Thickening Test Work (Outotec)

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    Project Overview

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    15km north of

    15km east of Blair

    Athol Mine

    Open cut,

    truck/shovel

    operation and in pit

    crushing & conveying

    system

    12Mtpa

    Expected mine life of

    17 years

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    High quality coal deposit with 192 Mt of proved open cut reserves Contained within Wolfang Basin - an elongated north-south trending basin

    a roximatel 5 km lon b 1.5 km wide

    Three major coal seams the Gowrie, Prospect and Wolfang seams

    Seams range from between 80 and 290 m below ground level o ang seam approx ma e y m c

    Approximately 17% of ROM coal will need to be washed over life of Project

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    Feed Rates

    > CHP Design Feed Rate 2500 tph> CPP Design Feed Rate 300 tph

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    CPP Equipment Utilised

    > DMC: -50 + 2 mm

    > Spirals: -2 + 0.1 mm

    > TBS & S irals were consider for the mid fraction

    > Spirals were selected as they are better understood and

    appropriate for the required separating density

    > Paste Thickener: -0.1mm

    > Large proportion of the fine fraction is clay, hence disposal of

    e ne rac on oes no comprom se energy recovery

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    CPP Yields

    rcu n mum om na ax mum

    Dense Medium Cyclone 22% 65% 96%

    Spirals 47% 75% 95%

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    Tailings Disposal Study

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    Traditional Disposal Methods

    Conventional Tailings Dam

    > Require large land areas.

    Co-Disposal Dam

    > Disposal of coarse and fine reject

    > Environmental challenges:

    o Soil erosion;

    .

    > Finer fractions fill voids created by

    larger fractions, thereby creating a

    o Water contamination.

    > Dan erous Fencin re uired.

    competent structure and can bedriven on in a week.

    > Approval for dam not sought in

    mining application for Clermont,

    than conventional tailings dam.

    > Downsides include higher power &.water consumption, pipeline wear

    and emplacement management.

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    Background Tailings Disposal

    > At FS all re ects were to be co-dis osed

    > Co-disposal would require 636 ML / annum

    > Initial roundwater studies re orted that this water would be

    available from underground sources

    > Later investigations found that this was incorrect

    > New philosophy had to be adopted Number of technologies investigated

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    Technologies Investigated

    > Filter Press

    > Vacuum Filters

    > Belt Press Filters

    > Paste Thickeners

    >

    Rejected from study due to high maintenance andpower consumption &

    Inabilit to dewater smaller fraction -38 m Screen

    bowl only)

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    Water Consumption

    69%

    70%

    71%

    66%

    67%

    68%

    ing(%)

    63%

    64%

    65%

    WaterSa

    61%

    62%

    Filter Presses Vacuum Filters Belt Press Filters Deep Cone

    Thickener

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    Power Saving Total Installed Power

    80%

    90%

    100%

    50%

    60%

    70%

    ing(%)

    20%

    30%

    40%

    PowerSa

    0%

    10%

    Filter Presses Vacuum Filters Belt Press Filters Deep Cone

    Thickener

    CPP co-disposal design had allowed for 1456 kW which includes 3 x co-disposal pumps, 2 x

    return water um s & 1 x land water um .

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    Capital Cost

    25%

    30%

    15%

    20%

    ase(%)

    5%

    10%

    italCostIn

    cre

    0%

    Filter Presses Vacuum Filters Belt Press Filters Deep ConeThickener

    Cap

    Price comparison based on fixed plant only, does not include mobile equipment cost.

    Cost of Dee Cone Thickener is not much reater than a conventional thickener.

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    Maintenance

    > Co-Dis osal

    Reasonably maintenance intensive due to pumping coarse

    material

    Rotation of pipeline every month and replacement 3times per year

    Frequent maintenance required on pumps

    > Filter PressesMore maintenance friendly than older models

    Red Mountain CPP experienced cake discharge problems

    with their filter press and so replaced them with belt press

    filters

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    Maintenance Continued

    > Vacuum Filters

    Most common dewatering method for flotation product

    Most economical unit to operate

    Maintenance costs could possibly increase using this fortailings

    > Belt Press Filters

    ,

    experienced very high maintenance costs and muchdowntime

    which dropped maintenance costs significantly

    > Deep Cone Thickener Least moving parts of any other option

    Robust and reliable

    By their nature should require least maintenance

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    Criteria Evaluation

    > Each o tion scored on a scale of 1-10

    > Each criteria equally weighted

    > Scores for water and ower were directl based on the savin s

    achievable compared with co-disposal

    > Score for the capital cost based on the price rise expected

    > Maintenance score was based on expected maintenance costs

    > Maintenance and capital costs evaluated based on inverse

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    Comparison Matrix

    Water Power Ca ital Maintenance TotalConsumption Consumption Cost

    Filter Presses 7 8 3 5 23

    Vacuum Filters 7 7 2 6 22

    filtersDeep Cone

    Thickener

    6 9 9 8 32

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    Paste thickeners operate in a similar manner toconventional high rate thickeners but produce an

    . .

    UWA]

    > e ect ng t e appropr ate occu ant

    > Using feed dilution systems

    > Using a deep tank for compression

    > Allowing for long bed residence times

    > Using a 30-45 tank cone

    > Using a specially designed rake system

    > Using shear thinning principles

    > Using a high degree of instrument and control

    Image courtesy of FLSmidth

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    Thickening Test work

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    Test Work by Outotec

    > Undertaken at Rio Tintos Technolo & Innovation Laborator in

    Melbourne

    Outotecs Supaflo High Rate Thickener

    94 mm Diameter

    > Test Material

    Blair Athol Coal Tailings

    SG: 1.7

    Quantity: 16 bulky bins

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    Test Work by Outotec

    > 94 mm Test Method

    Bed Height: 220mm

    Rake Speed: 2.5 rpm

    Stock slurry: Stored in 40 L agitated, baffled tub Feed sent via variable speed peristaltic pump

    Underflow pumped put by positive displacement pump

    Ciba FlocculantsMagnafloc X110, X125, 336, 1011 & 5250

    ,

    was selected for thickening test work

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    Test Work by Outotec

    > 190 mm Test Method

    Bed Height: 220mm Rake S eed: 2.5 r m

    Stock slurry: Stored in 2m3 agitated tank and fed at 3.7 4.3% w/w

    Feed sent via variable speed peristaltic pump

    Underflow pumped put by positive displacement pump

    > To achieve an underflow solids density of 50% w/w, a solidsloading rate of 0.23 t/m2h and flocculant dosage rate of 20 g/t

    were ideal conditions as seen in Run 2.

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    Dynamic Thickening (190 mm ) Results

    Run 1

    > Solids Loading

    Target Rate: 0.31 t/m2h

    Actual Rate: 0.30 t/m2h

    > Underflow Density

    Calculated Density: 48 % w/w

    Actual Densit : 47% w/w

    > Flocculant Dosing

    Target Rate: 30 g/t

    c ua a e: g

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    Dynamic Thickening (190 mm ) Results

    Run 2

    > Solids Loading

    Target Rate: 0.23 t/m2h

    Actual Rate: 0.24 t/m2h

    > Underflow Density

    Calculated Density: 50% w/w

    After Feed Interru tion: 57%

    > Flocculant Dosing

    Target Rate: 20 g/t

    c ua a e: g

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    Dynamic Thickening (190 mm ) Results

    Run 3

    > Solids Loading

    Target Rate: 0.31 t/m2h

    Actual Rate: 0.32 t/m2h

    > Underflow Density

    Calculated Density: 47 % w/w

    Actual Densit : 46.6% w/w

    > Flocculant Dosing

    Target Rate: 20 g/t

    c ua a e: g

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    Construction Activities

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    ST201 ( ROM Feed Bin & Apron Feeder)

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    Crushing Station ST201

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    CPP & Portion of OLC

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    CPP

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