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    Currently the mining industry is

    increasing its focus on operational

    excellence and safety performance

    toward zero-harm levels. Factors driving this

    increased focus include the need to obtain

    greater efficiencies not only to address the

    rising capital costs for mining assets such as

    equipment, fuel, tyres, and manpower, but

    their overall operation as well, and in-pit

    crushing and conveying is an important part of

    this. Reduction of CO2 emissions is also a key

    driver.

    There has been a tendency in the mining

    press in recent years to focus only on the

    newest fully mobile in-pit crushing and

    conveying systems from the various OEMs.

    While these do represent one of the most

    innovative and exciting parts of the market, it

    is important to remember that other, related

    areas such as semi-mobile systems, long

    distance waste conveying and disposal via

    spreader, and even the application of other

    technologies such as bucket-wheels and

    surface miners in certain situations, all deserveattention. This is highlighted by the latest

    industry order for a semi-mobile system – to be

    supplied by FLSmidth to PT Adaro Indonesia.

    There also continue to be new variations on

    the fully mobile theme, as shown by

    FLSmidth’s Dual Truck Mobile Sizer.

    Hotspot areas currently include the bauxite

    and iron ore mines in Brazil; as well as Indian

    and Chinese coal and coal overburden. The

    actual number of installed systems is still

    relatively small, with some of the previously

    delivered fully mobile systems having seen

    intermittent use for various reasons. In addition

    to this is the industry reluctance to be the

    guinea pig for new (or newly considered)

    technology. However, overall there is a feeling

    among both OEMs and the mining houses,

    that IPCC as a concept is gathering

    momentum – this is shown by the landmark

    MMD order in China for Pingshuo, as well as a

    number of orders bound for Brazil, which are

    in the process of being built but are covered by

    confidentiality agreements.

    In waste mining technologies, the traditional

    stripping machine in the Brazilian bauxite

    mining industry is the crawler dozer, or in

    some cases, small draglines. However, with

    increasing overburden depths and higherlabour and fuel costs, some groups are again

    thought to be looking at bucket wheel and

    spreader technology, as well as excavator,

    hopper and direct casting spreader designs.

    The reasons for the IPCC momentum

    include there being no let up on increases in

    truck haulage costs, which can represent

    approximately 50% of mining capital and

    operating costs in large open-pit mines. That

    said there is a distinction to be made between

    IPCC in large flat bedded coal, iron ore and

    bauxite mines and their application in large,

    deep hard rock open-pit mines.

    Dave Tutton, Consultant Mining Engineer

    comments: “Large open pit copper and gold

    mines focus on maximising value by aggressive

    vertical development rates that are not

    conducive to semi-fixed structures such as

    crushers, conveyors and conveyor crossovers.

    To find greater application for IPCC, this part

    of the industry will require more flexible

    systems and the ability to accommodate them

    within the mine plan without significantly

    impacting the metal and waste schedules. Thiswill require innovation from both the supplier

    and the mine operator.”

    Despite these challenges, there is definitely

    renewed interest in high tonnage IPCC systems

    In Pit Crushing and Conveying –

    gathering momentum

    Paul Moore spoke to theleading IPCC players aboutthe ongoing interest andresearch into this technologyarea, as well as new ordersand existing systems

    One of the two Sandvik 8,000 t/h semi-mobile IPCC 

     plants at the Aitik mine in Sweden

    IPCC DEVELOPMENTS

    28 International Mining MAY 2011

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    in base metals for processing waste rock.

    While the majority of projects are looking at

    semi-mobile systems with gyratory crushers, a

    few may also be suitable for sizers. Large open

    pits continue to evolve requiring reassessment

    of crusher station locations – highlighted by

    BHP Billiton’s recent commitment to the

    Escondida Ore Access project (EOA), the first of

    a number of development options that will

    underline Escondida’s status as the world’spremier copper operation. It involves a major

    relocation of semi-fixed crushing and

    conveying infrastructure. The EOA project will

    relocate the crushing and conveying facilities

    currently located inside Escondida’s main pit to

    improve access to higher grade ore and

    thereby support higher production from 2013.

    The project is expected to cost $554 million

    and will be completed by mid-calendar year

    2012.

    In Australia, the commissioning of Sino Iron

    project’s four semi-mobile crushing and

    conveying systems from ThyssenKrupp is

    ongoing – these will be the largest in-pit

    gyratory crusher installations in Australia.

    Mechanical installation of the first in-pit

    crusher is nearing completion, while the

    second crusher has been delivered to site.

    Employing gyratories, each will have the

    capacity to crush 4,250 t/h of magnetite and

    are powered electrically by the project’s

    combined-cycle gas-fired power station. When

    ready for relocation, the crushers will be un-

    coupled and moved to the new location using

    crawler units.

    The following summarises some of the key

    developments at the major IPCC equipment

    players including existing machines and new

    deliveries. In addition to the OEMs, the key

    consultants are playing a major role – SKMhaving worked with Rio Tinto on the Clermont

    project, Vale at Carajas and in conjunction

    with SNC-Lavalin on an expansion at the

    Cerrejon mine in Colombia; AMEC is working

    with CSN in Brazil on a planned expansion;

    and Snowden and JT Boyd are also working on

    several key projects.

    Terra Nova Technologies (TNT), a wholly

    owned subsidiary of AMEC, is a premier

    supplier of material handling systems,

    including patented mobile stacking techniques

    IPCC DEVELOPMENTS

    30 International Mining MAY 2011

    The signing ceremony between MMD Group and 

    China Coal 

    INNOVATION THROUGH EXPERIENCEEfficient, high capacity MMD IPCC solutions

    Fully Mobile Sizer StationOverburden

    BMA Goonyella, Australia

    Semi-Mobile Sizer StationOverburden

    Mae Moh, Thailand

    The Award Winning MMD LPMSOverburden

    Pingshuo, China

    Relocatable SystemsBauxite

    MRN, Brazil

    THE MMD GROUP OF COMPANIESW W W . M M D S I Z E R S . C O M

    http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/http://www.mmdsizers.com/

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    32 International Mining MAY 2011

    IPCC DEVELOPMENTS

    that are ideal for overburden

    spreading. They are a

    departure from traditional

    spreading methods, and

    make it possible to spread

    waste using self-advancing

    dumps, eliminating the need

    for shiftable conveyors and

    ex-pit trucks. IPCC handling

    of overburden, spread using

    self-advancing dumps,

    reduces the initial startup

    time and costs for greenfield

    sites.

    As announced in the April

    2011 issue of  IM , a contract

    was signed in February

    between China Coal Energy

    Group and MMD for thesupply of an IPCC system that

    includes MMD's award winning Low Profile

    Mobile Sizer (LPMS) fully mobile rig. This unit is

    not only the first of the "third generation"

    MMD high-capacity (>5,000 t/h) fully mobile

    sizing units to go into operation but it will also

    be the first MMD fully mobile unit to go into

    operation in China, where the group has

    already been highly successful with semi-

    mobile systems, in addition to a number of

    other countries, including seven sizer stations

    designed for Mae Moh in Thailand.

    The new order arose from a tender issued

    by China Coal for the Pingshou East open pit

    mining area in Shanxi province. All of the

    major manufacturers took part in the tender

    and MMD admits it was far from offering the

    lowest cost solution, but had the advantage of

    past experience in having delivered successful

    fully mobile units of this capacity before – the

    first being BMA’s MS1 unit which went into

    service at the Goonyella Riverside mine in

    2001. MMD also attributes the order success

    to the unique features of the LPMS sizing rig,

    which incorporates a number of innovations

    and unique features, the culmination of

    experience gained from previous models.

    While headquartered in the UK, MMD has

    its own wholly-owned operations on every

    continent and used its Beijing-based company

    MMD China in the finalising of the deal and

    negotiations, which is part of its MMD Asia

    Pacific division and is run entirely by Chinese

    nationals. Technical support is supplied from

    UK-based specialists only when necessary. A

    similar approach is being used for the

    manufacture of the units on order, in thatspecialist components are being imported but

    the balance are being made in China – where

    MMD has its own manufacturing facility and a

    second is in the planning stage.

    The MMD system on order will be used to

    handle overburden, consisting primarily of

    sandstones with a UCS (hardness) of up to 120

    Mpa and a density of 2.7 kg/cm3. The horizons

    contain several muddy layers and are expected

    to get sticky in the short wet season, as the

    daily precipitation can exceed 150 mm/d. The

    material, produced from 15 m benches of up

    to 1,540 m in length, will be loaded by a 60

    m3 capacity rope shovel into the MMD LPMS

    mobile sizing rig which is mounted on a

    custom built MMD carrier. The material is then

    transferred from the 150 m³ low profile

    hopper by a low angle MMD D9 apron plate

    feeder, fitted with an electro-mechanical

    variable speed drive, capable of providing a

    controlled flow of material to the MMD 1400

    series mineral sizer at a rate of over 9,000 t/h.

    The sizer reduces the ROM material

    (maximum dimensions of 2.5 m x 2.5 m x 2 m)

    to a product suitable for belt conveying (400

    mm maximum) before feeding this onto a

    short sacrificial belt which carries it to the rigs’

    integral slewing/luffing take-away conveyor.

    This in turn feeds the MMD hopper car

    mounted on the movable face conveyor via an

    independent mobile 70 m bridge conveyor.

    The face conveyor, subsequent haulage system,

    stacking and spreading systems are not part of

    MMD’s scope of supply, but are subject to

    separate tender processes.

    When in full production, the MMD sizing rigwill move frequently, up to twice an hour, with

    the normal advance being a distance of ± 5 m.

    The LPMS rig’s low profile, compact, balanced

    design and the absence of any stabilising jacks

    when coupled with its

    ability to continue sizing

    whilst moving will make for

    a virtually seamless loading

    operation possible,

    according to MMD.

    The MMD supplied units

    have been designed to

    work around the clock

    which means in the normal

    mining environment it will

    see about 6,500/7,000 h of

    service a year. The absence

    of a slew ring, combined

    with the inherent low

    maintenance of the MMD

    sizer, make it the least

    maintenance intensive

    element in the whole IPCCsystem. This should lead to

    a situation where the minimal routine

    maintenance of the MMD supplied units can be

    accomplished within the time-frame of the

    normal planned preventative maintenance

    stoppages.

    MMD sees one of its main strengths in

    being a relatively small company, which

    patented the sizer in the first place back in

    1978 – with the sizer remaining at the core of

    any viable modern IPCC system. The company

    managed to convince the industry then of the

    advantages of sizer technology and was the

    first to deliver a fully mobile IPCC solution on

    which it has been able to make many key

    improvements based on real in-the-field use.

    FLSmidth has been one of the groups at

    the forefront of fully mobile IPCC systems in

    recent years, with its development of the Triple

    Track Mobile Sizer (TTMS). The group delivered

    a major overburden removal system based on

    the TTMS to Fortescue Metals Group (FMG) in

    2008, as well as subsequently developing the

    Dual Truck Mobile Sizer (DTMS).

    The TTMS is designed for the removal of

    overburden and at FMG is used to expose the

    iron ore floor allowing extraction by other

    mechanical mining processes. The TTMS

    system derives its name from its unique

    suspension undercarriage. It is triangular in

    nature and thus ensures an inherently stable

    three-point suspension for good stability. This

    design reduces stress on the main frame

    structure. FLSmidth believes that the system is

    unique in the fact that it was designed to be

    completely mobile and move under load. There

    are no outriggers and/or feet that need to belowered to improve stability. The TTMS operator

    simply controls the machine using a joystick to

    follow the excavation path of the shovel.

    The DTMS is an innovative technical solution

     A computer generated image of the LPMS design

    being delivered to Pingshuo

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    that offers haul truck flexibility with complete

    mobility utilising a shiftable face conveyor.

    FLSmidth engineered a machine incorporating

    hinged, flat hoppers. The system can be

    relocated as the haul distances become too

    great. When a truck backs into the skip, it will

    back against the curb in the floor of the skip. It

    will dump its load on the skip floor, pull slowly

    ahead, lower its bed, and pull away. After the

    truck clears the end of the skip, the skip can

    be raised. As the skip is elevated, it begins to

    pour material from the discharge of the skip

    and deposits the material into the apron

    feeder hopper. As material is introduced onto

    the apron feeder, the apron feeder begins

    conveying the material to the sizer. As the

    material leaves the apron feeder, it falls into

    the sizer. After being crushed, the material is

    discharged onto the discharge conveyor where

    it is conveyed to the bench conveyor. This

    process is performed while another haul truck

    is depositing material into the twin skip.

    In the semi-mobile area, FLSmidth has

    recently signed a contract in Jakarta worth in

    excess of $135m with PT Adaro Indonesia to

    supply materials handling equipment to its coal

    mine in the Tanjung district of South

    Kalimantan. The materials handling

    equipment will be part of Adaro's

    expansion of its mining operations

    and will decrease the average

    hauling distance of the overburden

    trucking operations as well as

    reduce the company's dependencyon oil. The contract comprises an

    out-of-pit overburden crushing and

    conveying system, consisting of

    FLSmidth ABON sizers, RAHCO overland

    conveyors, and RAHCO mobile stacking

    conveyors. The system has a capacity of

    12,000 t/h and an annual overburden volume

    of 40 Mbcm. The contractual elements

    regarding construction, supervision and

    management, as well as field service, will be

    supplied by FLSmidth Indonesia.

    “This material handling contract is the first

    in Indonesia and reflects a growing market in

    the region, particularly in the minerals sector

    where mining companies are expanding. Being

    the first of its kind in Indonesia, the project will

    act as a catalyst for other potential orders in

    the region and for our participation in the

    continued expansion of Adaro's mining

    activities, which makes the contract significant

    for FLSmidth,” Group CEO of

    FLSmidth Jørgen Huno

    Rasmussen commented.

    “Adaro has

    increased its

    production every

    year since 1992

    and we are now among the top five exporters

    of thermal coal in the world – and all from just

    one site. Overburden mining and haulage is

    one of our biggest challenges. In 2010 we

    hauled 226 Mbcm of overburden, and this

    year we are planning to haul more than 290

    Mbcm. The equipment supplied by FLSmidth

    will increase the efficiency with which this

    large amount of overburden is transported and

    help secure Adaro's unbroken track record of

    continuous growth,” said Garibaldi Boy Thohir,

    President Director of Adaro Energy.

    The order will contribute beneficially to

    FLSmidth's earnings until the end of 2012.

    FLSmidth’s operations in Spokane, Washington

    and Boise, Idaho are jointly executing the

    project, with FLSmidth Spokane taking the

    lead. The sizer stations themselves will be

    semi-mobile and are being designed andsupplied out of Boise, as are the semi-mobile

    head and tail stations.

    Sandvik Mining & Construction was the

    lead contractor in the delivery of a large semi-

    mobile IPCC system that has been operating

    successfully at the Mae Moh mine in Thailand

    since 2002. The group also installed two 8,000

    t/h semi-mobile IPCC systems at the Boliden

    Aitik mine in Sweden and two 10,000 t/h jaw

    crusher based systems with scalping at the

    Vale Carajas mine in Brazil.

    Its fully mobile solution, the PF300, offers a

    new stability concept according to the group.

    Following the launch of the design, Sandvik's

    Thomas Jabs, Global Product Line Manager

    Materials Handling commented: "We see

    strong signs of interest in fully-mobile crushing

    concepts in all the big mining markets,

    engineering houses and operating houses

    worldwide. They are seeking

    alternatives to truck intensive mining.

    Our newly developed fully-mobile

    crushing plant makes the IPCC method a

    better alternative to traditional truck

    haulage due to lower operating and

    maintenance costs, higher energy efficiency

    and reduced CO2 footprint.

    This is where the fully mobile crushing

    concept perfectly fits and what the

    PF300 is developed for. Sandvik

    improvements to IPCC help ensure

    higher production and profitability,

    while reducing dust, noise and

    pollution".

    The design allows loading of the

    crusher via hydraulic or rope

    shovels without any temporarysupport, keeping the system fully

    mobile and rock solid under all

    conditions while machine

    excitement is significantly reduced. This not

    IPCC DEVELOPMENTS

    34 International Mining MAY 2011

    The first Sandvik PF300 is expected to begin

     production in Brazil in early 2012

    The two hopper FLSmidth TTMS unit at Fortescue Metals Group, Australia

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    only keeps availability at a high level,

    but also improves the positioning of the

    machine. The PF300 can either work in

    combination with a belt wagon, mobile

    transfer conveyors, or load bridges as

    the connecting downstream link to the

    face conveyor. According to Sandvik, the

    machine can be equipped with a sizer,

    double-roll crusher or hybrid-crusher, to

    address the needs of multiple

    applications, with coal, overburden, iron

    ore and oil sands listed as the main

    application areas for the machine.

    To date the group has yet to deliver a

    fully mobile system, but in late 2009

    orders for two units were placed. One

    of these was from a Brazilian customer

    for a complete crushing and materials-

    handling system that includes a PF300mobile unit. Fabrication of the system is

    almost completed; delivery of the

    components and erection will start in the

    coming months and the unit is expected to be

    operational in early 2012.

    Sandvik is also working on the possible

    installation of a semi-mobile IPCC system in

    Chile at a copper-gold project.

    P&H Mining Equipment offers automation

    technology combined with faster, information

    processing technology to improve the

    efficiency of its electric mining shovels, but is

    now adopting unique automation technology

    to help improve operational excellence in the

    material handling processes used in open pit

    mining. To help increase overburden material

    handling efficiency and safety, P&H Mining

    Equipment has developed a range of in-pit

    crushing-conveying technology options that

    can be applied in fixed, semi-mobile and fully

    mobile configurations.

    These include a stationary system, comprised

    of a sizer or feeder-breaker linked to a

    conveyor system, for example, that can be

    situated near a shovel tasked with loading a

    small but well-utilised fleet of haul trucks,

    shortening their load-dump-return circuit

    distance – an arrangement that frees up other

    mine assets to concentrate on moving more

    valuable commodity material.

    A semi-mobile tandem design is also

    offered, consisting of two ‘feeder-breaker-

    sizers’, one of which continues to operate

    while the other unit is re-positioned to

    minimise the advance of shovel-truck loading

    positions. Finally, the company can offer the

    4170C, a fully mobile, crawler-mounted

    mining crusher unit that is integrated with the

    mining shovel to which it is paired for efficient,

    synchronised relocations.

    P&H Mining Equipment says that it offers

    “unique IPCC system advantages including an

    application-optimising process that includes a

    ‘4D Visualisation’ system that combines a

    mine’s 3D topography with IPCC system

    application scenarios to help visualise the

    interplay of the shovel, feeder-

    breaker-sizer unit, conveyors and

    spreaders as the overburden and

    commodity mining phases

    advance.”

    P&H further applies “total cost of

    ownership” or TCO analysis to

    provide insights into cost flows and

    cost structure scenarios, factoring in

    life-of-mine horizons and annual

    tonnage requirements as the IPCC

    system options are applied year-

    over-year.

    Using such powerful analytical

    tools, mine management can obtain

    useful comparisons to help identify

    IPCC configurations from shovel to

    spreader that point toward optimal

    material throughput for reducedoperating cost.

    P&H IPCC systems also include a

    powerful “Centurion” supervisor control and

    data acquisition or SCADA system that

    monitors all of the systems on the shovel as

    well as the IPCC to which it is tasked.

    Important advantages of that SCADA include

    optimisation of the shovel and the IPCC system

    as they interact, plus synchronisation of the

    shovel and IPCC maintenance schedules to

    help the mine obtain “unmatched” IPCC

    system availability.

    P&H shovel-IPCC systems are supported by a

    global network of P&H MinePro Services teams

    that provide a full range of life cycle

    management coverage including logistics, 24/7

    emergency response, remote health

    monitoring and reliability-centred maintenance,

    plus performance-enhancing upgrades that

    help increase reliability and productivity.

    ThyssenKrupp Fördertechnik is one of the

    groups that has played a major role in the

    development of cost-efficient in-pit crushing

    systems and given its history of installations

    dating back many years, is one of the most

    experienced and successful manufacturers of

    fixed and semi-mobile crushing systems, which

    has also helped the company make the move

    into the fully mobile arena. The first major

    milestone in open pit mine equipment

    development of this kind for the Mining

    Business Unit of ThyssenKrupp was the world’s

    first fully mobile crushing system of a new

    design, delivered to the YiminHe coal mine in

    China in 2007. The crushing plant processes

    ROM coal at a rate of 3,000 t/h. This

    successful operation at YiminHe led to afurther order for four fully mobile crushing

    systems – which are currently under

    construction – for the Baiyinhua coal field in

    China. Three of the four systems will be used

    IPCC DEVELOPMENTS

    36 International Mining MAY 2011

    One of P&H Mining Equipment’s offerings is the

    4170C; a fully mobile, crawler-mounted mining

    crusher unit that is integrated with the mining shovel 

    to which it is paired for efficient, synchronised 

    relocations

    Heavy duty conveyor beltsConveyor belts that have to handle coarse crushed rock, particularly on exit from a primary

    crusher, have to have enhanced impact resistance and strength compared to standard material

    transport conveyors. Goodyear has just launched its ConquestXP line of heavy duty belts, which

    have potential application in the IPCC market. Designed using computer modelling and FEA

    analysis, ConquestXP has a new dual twill fabric weave layer offering improved load bearing and

    impact resistance. Design engineers used an enhanced Dynamic Impact Tester to simulate

    loading impact force and its effects on belting. The dual layer twill fabric enables high transversetear strength, which minimises tears that result from material punctures as well as edge tears

    from misaligned belts. Dynamic and static testing also means that ConquestXP belts can provide

    superior mechanical fastener retention compared with mutli-ply and straight warp constructions.

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    to remove overburden, each having a nominal

    capacity of 6,000 t/h. One 3,000 t/h system

    will be used for coal processing.

    In 2010 ThyssenKrupp then received an

    order for two fully mobile crushing systems for

    overburden handling in an iron ore open pit

    mine in Brazil. Each crushing plant is equipped

    with a double-roll crusher and operates in the

    mine together with a shovel crushing

    overburden at a rate of up to 3,900 t/h. A

    particular challenge here was the planning and

    realisation of such a system for a mine typewhich typically extend downwards with fairly

    steep pit walls, in comparison to coal mines,

    which typically have relatively wide benches.

    Ongoing research and development,

    including the realisation of higher capacity

    ranges or considering different types of mining

    operations – is are carried out by

    ThyssenKrupp with the aim of optimising fully

    mobile crushing and conveying systems

    according to customer requirements.

    In 1995 Takraf started a new chapter in its

    production history. That involved the planning,

    calculation, design, production and assembly

    of primary sizer rigs (stations), which are

    designed as stationary and semi-mobile units,

    including the associated equipment. Takraf

    states that is has "successfully positioned itself

    as a worldwide supplier specialising in

    equipment that comminutes, conveys and

    discharges waste in consolidated bedrock

    mines." The company now has 19 large-scale

    sizer rigs that have been commissioned with

    designed throughput rates of 2,500-12,000

    t/h.

    Following on from this came the

    development of mobile sizer rigs - specifically

    the fully mobile BRF-W2-12000. This rig is

    currently deployed in Queensland, Australia at

    the Clermont mine operated by Rio Tinto Coal

    Australia and is designed to size hardoverburden with a hardness up to 175 MPa.

    The rig was developed and designed in a

    record time of only six months and has been in

    use since July of 2009. The group states that it

    is also already working on “even more

    effective solutions relating to continuous

    mining technologies used in bedrock.”

    The Clermont sizer rig operates in

    conjunction with a conveyor system, a tripper

    car and an overburden spreader. It has a

    design throughput of 12,000 t/h and weighs

    MAY 2011 International Mining 37

    Fully mobile ThyssenKrupp crushing plant design with

    conveyor bridge in multiple bench operation

    IPCC DEVELOPMENTS

    http://www.tk-mining.com/

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    approximately 1,500 t, making it one of the

    largest mobile sizer rigs currently operating in

    the world.

    Materials can be comminuted, transported

    and dumped continuously thanks to the

    mobility of the entire complex system. As a

    result of that, it is possible to achieve

    considerably higher outputs compared with

    discontinuously operating technologies.

    Another advantage of the complex system is

    that it can be controlled centrally by only one

    system operator, whose station is located on

    the overburden spreader. With the aid of a

    special monitoring system all necessary data

    are made available to the system operator and

    ensure a reliable operation of the entire

    system.

    Due to the machine's scope of work and

    taking into consideration stability under all

    operating load conditions and special load

    cases as well as the operating weight, Takraf

    implemented a so-called triple crawler

    undercarriage with six individual crawler tracks

    arranged in pairs for this sizer rig. The

    supporting forces are distributed to each pair

    of crawler tracks statically via three support

    points on the substructure. A change in the

    sizer rig's direction of travel is implemented by

    aligned swivelling of the two pivotable control

    crawler tracks at two of the support points

    using the tiller claws.

    All individual crawler tracks are mounted

    such that they can float independent of one

    another to accommodate the uneven terrain.

    Each individual crawler track is driven by

    means of electric motors for advancing thesizer rig.

    The superstructure is mounted on the

    undercarriage such that it can swivel by means

    of a geared ball bearing and is used for

    accommodating and supporting the apron

    feeder, the sizer discharge conveyor and the

    boom conveyor, which is equipped with its

    own hoisting mechanism and slewing

    mechanism. Thanks to the slewability of the

    superstructure and the separate adjustability of

    the boom conveyor, it is possible to achieve a

    very high positioning accuracy of the material

    feed and/or material transfer.

    The twin shaft sizer is positioned centrally

    on the superstructure. To minimise any repair

    related downtime, a solution was found that

    allows for moving the twin shaft sizer

    including drive systems over its entire length in

    a longitudinal direction to the optimum service

    position where there is sufficient work space.

    Moreover, there is also a possibility for side-

    to-side movement for removing the lateral

    drive systems. The material is supplied by a

    rope shovel of the type P&H 4100XPC with the

    aid of a feed hopper to the apron feeder. The

    maximum feed volume is about 56 m³, which

    corresponds to a weight of about 110 t. The

    capacity of the hopper is designed at 170 m³.

    This capacity guarantees a continuous supply

    of material to the twin shaft sizer while taking

    the loading cycle of the rope shovel into

    account. Level sensors monitor the height of

    the material on the apron feeder and regulate

    the transport speed.

    The apron feeder is supported in a

    "statically determined" manner in every

    operating mode. During excavation, the apron

    feeder generally rests on the subgrade by way

    of a pontoon. This solution offers the

    advantage that all loads caused by the materialfeed are distributed directly to the subgrade.

    During transport the apron feeder can be

    raised and lowered using the hydraulic

    cylinders arranged on both sides. The material

    (maximum ROM size 2.05 m x 2 m x 1.5 m) is

    supplied by the apron feeder to the twin shaft

    sizer by way of a feed hopper. The crushed

    product material is specified to have maximum

    dimensions of 450 mm x 350 mm x 350 mm

    for transport via the conveyor systems. A

    discharge belt that is arranged below the twin

    shaft sizer transports the comminuted material

    to the belt of the boom conveyor by means of

    a slewable central hopper. IM 

    This entire subject from fixed to semi-mobile

    and fully mobile IPCC as well as related 

    technologies will be covered at IM’s

    forthcoming IPCC event in Belo Horizonte,

    Brazil from 21-23 September, 2011. Speakers

    have already been confirmed from SKM,

    Snowden, FLSmidth, Sandvik and others. For 

    more information contact the IM Editor, Paul 

    Moore at [email protected]

    IPCC DEVELOPMENTS

    38 International Mining MAY 2011

    The Takraf machine at Clermont has a design capacity 

    of 12,000 t/h

    ThyssenKrupp fully mobile crushing plant design with

    conveyor bridge for single bench operation