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Long detours may make the transport of rawmaterials from the mining area to theprocessing plant considerably morecomplicated and expensive than is perhapsnecessary. However, local geography such asmountainous terrain, heavily populated areas orwide rivers interferes with smooth material flow. At a cement plant in Sudan, a direct, straightlink between the mining area and the processingplant seemed impossible to establish, butDoppelmayrs RopeCon made it possible.
To meet the daily demand of 9,000 t oflimestone for Berber Cement Cos new cementplant, a modern crushing plant has beeninstalled 8 km away from the processing planton the west of the River Nile. Landtransportation of 9,000 t/d encounters themassive natural obstacle of the Nile, which issome 850 m wide in this area. So transport ofthe material from west to east could only be achieved by building a bridge across the river,using small barges or by employing a ropewaytypesystem, crossing the river between twotowers.
A study was commissioned to investigatewhether RopeCon might be a suitablealternative. The system combines provenropeway technology with the features ofconventional belt conveyors. The continuousconveyor is elevated above the ground. RopeConeasily crosses obstacles such as deep valleys,mountainous terrain, rivers, roads or otherinfrastructure, thus avoiding unnecessarydetours and allowing for straight routesbetween loading and discharge points.
RopeCon consists of aatieber clutch flat beltwith corrugated side walls. The belt may befabric-reinforced or a steel cord belt, dependingon the application. The corrugated side walls arecold-bonded or vulcanised onto the belt. Theindividual belt sections are vulcanised togetherto form one continuous belt, just as aconventional belt conveyor. The belt is fixed to steel axles arranged atregular intervals which support the belt. Polyamide running wheels are fitted to eitherend of the axles. These wheel sets run on trackropes and provide positive belt guidance whilepreventing the belt from skewing. Thecombination of polyamide wheels on steel trackropes minimises rolling resistance and thereforeenergy requirements.
The galvanised, fully locked steel track ropeson which the wheel sets run are of the type usedfor suspension bridges or ropeways. RopeConuses three pairs of ropes: The bottom-most ropepair supports the bottom belt while the ropepair in the middle supports the top belt. Theupper-most rope pair gives additional stabilityto the structure and serves as the travelling rope for the inspection vehicle by means of whicheach point along the line can be accessed. Trackrope frames are fitted to the ropes at regularintervals to maintain the ropes in their relevantposition and to distribute the loads. The ropeshave fixed anchoring at both ends and areguided over tower structures.
The belt is driven and returned by a drivedrum in the head or tail station. After thematerial has been discharged, a turning deviceturns the belt by 180 to bring the soiled side ofthe belt upwards once more and to preventresidual material from falling off the bottombelt. The belt is turned once more before it runsonto the drum again in the loading station. Thedrive system is similar to that of a conventionalbelt conveyor and consists of a gearbox and anelectric motor. RopeCon features twoindependent mechanical braking systems. Allbraking actions are regulated to ensure constantdeceleration and a
Berber Cements loading station is located onthe west shore of the river, immediately behindthe crusher. Crushed stone arrives on trucks andis loaded via a feed conveyor and a chute. TheRopeCon system crosses the Nile with a singlelarge rope span between two tower structurespositioned on either side of the river. It is notnecessary to have a support structure in theriver. The total length of the system is about3,465 m from the loading station to thedischarge station. Its transport capacity is 700t/h. There were other considerations for thissolution, one of them being the space requiredby ground-based systems. In this desertcountry, the shores of the Nile form one narrowcorridor of fertile land used for farming. A roadwould cut right through this valuable strip ofland. RopeCon spans this corridor with minimalinterference.
On the east shore, several settlements borderthe farm land. A transport solution relying ontrucks would expose residents to considerablenoise and dust. RopeCon avoids these problemsand its low rolling resistance helps keepoperating costs low, whereas the maintenanceof an entire fleet of trucks as well as of a roadwould have resulted in considerable expense. Virtually all RopeCon moving parts are mountedon the belt, which means that they keeptravelling through the stations where they canbe easily maintained. No complicatedmaintenance lines or platforms are required.Any inspections of the line can be performedwith the inspection vehicle.
Minera Media Luna, a 100% owned subsidiaryof Canadian Torex Gold Resources hasdeveloped its first gold mine in Mexico at itsMorelos gold project. Doppelmayr was awardeda contract to build a RopeCon system fortransporting the ore from the mine down to astockpile in early 2013. The aerial continuousconveying system will transport the material atan hourly design capacity of 1,000 t through thesteep and tough terrain from the crusher over adistance of 1.3 km. The RopCon system is suitedto this project due to its low operational cost,with the system generating power due to thedifference in height. Construction is scheduledto start for the summer of 2014 withcommissioningplanned for the winterof 2014/2015.
Beumer hasestablished someequally spectacularconveyor systems (asthe picture shows) andsays thatmanufacturers thatnot only supplyeverything from onesource but alsoundertake thecomplete project tothe point of turnkeyhandover are indemand. Beumer alsoacts as the maincontractor on behalf ofits customers. A significant trend is that moreand more clients want to commission theirsystems in a turnkey state, says Dr GerdOberheuser, Head of System Technology atBeumer Group. EPC or EPCM are the buzzwordshere.
With the acquisition of Enexco TeknologiesIndia in 2011, the group has expanded itsbusiness activities in India and in doing so hasstrengthened its presence, particularly in thecement industry, in one of the worlds mostimportant growth markets. Beumer systemsolutions, such as belt conveyors, are also inincreasing demand in the coal industry.
For a quotation to be accepted, contracts areoften only placed on an EPC basis, remarksOberheuser. This means that, as well assupplying the equipment, Beumer is responsiblefor the whole process. This includes the designof the entire system, the installation, thecommissioning and the instruction ofsubcontractors. Not only does a high availabilityof machines and systems play a decisive role,but also optimum support. For this reason,Beumer has set up competence centres in theCzech Republic, in Austria, at its headquarters inBeckum, and in North America. These take careof research and development, sales, projectmanagement and purchasing.
Beumer too points to the considerabledisadvantages of trucks. Road building isexpensive, and the more raw materials have tobe transported, the more journeys have to bemade. Added to this are the operating costs andemissions caused by trucks both with regardto fuel consumption and personnel costs as wellas noise and dust. A direct belt conveyorsystem route allows the material to betransported much faster than by truck. Inaddition, belt conveyors can be operated with significantly fewer personnel. Another aspectcompared with trucks is the lower energyconsumption, which at the same time reducesCO2 emissions. Depending on the project, beltconveying systems need up to 90% less primaryenergy than comparable truck transportation.
Belt conveyors can overcome long distances,steep gradients and tight curves, and can beindividually matched to the particular task andtopography. Use is made of durable, tensionresistantconveyor belts. In doing so Beumeruses various calculation programs to determinethe optimum belt design. These enable tensileforces to be analysed and also forces whichoccur due to acceleration and deceleration always taking into account the intrinsic weightof the belt and the transported material. Theyare also used to determine possible curve radii.The company also provides advance feasibilitystudies.
In addition, the belt position is calculated inadvance with the appropriate curve radius forthe empty and loaded states. With their slenderlines, belt conveyors overcome broken terrainand other obstacles such as rivers, roads,buildings or rail tracks. Horizontal and verticalcurves in the routing can also be overlapped. Depending on the requirement, Beumer offersopen troughed belt conveyors for higherthroughputs and larger mass flows as well aslarger curve radii, and enclosed pipe conveyorsfor products which need to be protected againstthe effects of the environment.
At the port of Callao in Peru, Beumer will beinstalling pipe conveyors with a length ofaround 3 km to transport copper, lead and zincconcentrates, for completion in 2014. Depending on the landscape and environmental conditions, we can install overland conveyors with horizontal curves with lengths of up to 20 km, explains Oberheuser.Gradients of up to 15o can be achieved depending on the characteristics of the materials to be conveyed. After planning, installation and commissioning, maintenance and service are no more laborious than with a straight conveyor. On average, the annual maintenance costs are only around 2% of the investment sum.
In Canada, Beumer iscurrently installing a conveyorwith a length of 3.48 km for alarge mining operation. This willconvey up to 6,000 t/h of ironore. This large-area conveyorsystem must withstand extremetemperatures of down to -40Cand heavy snowfalls. Beumerhas designed all mechanical andstructural elements for theextremely low temperatures. For example, the system is fitted with a feedconveyor and an unloading system with trippercar.
As main contractor, Beumer is equipping anew distribution centre off the shore of Malaysiawith 17 trough belt conveyors with a total lengthof 12 km for a large iron ore exporter. Theconveyors will ensure swift transport of iron orefrom super-size freighters to the mainland.Beumer will deliver and install the conveyors,put them into operation and take full charge ofengineering, all according to a strict timetable.
Codelco has awarded a large scale conveyorsystem contract for its El Teniente mineexpansion to Takraf. The system connects anewly developed orebody to the existingprocessing facilities. In its final stage it willtransport primary crushed copper ore at morethan 12,000 t/h. Running at 6 m/sec,the 2 m wide beltconveyor system willcarry the ore over almost 12 km. The threeprincipal conveyors, one 9,000 m long tunnelconveyor and two 1,000 m steep uphillconveyors (15) feed the existing stockpile andin the future a new stockpile. The contract also involves the extension of anexisting conveyor line. For this it will benecessary to carry out the final tie-in within justa four day shutdown. Constructability is therefore of fundamental importance to the success of this project and is incorporated in all design aspects.
El Teniente will be able to run the conveyorsystem initially at lower speeds to suit the lowerconveying capacities in the earlier years ofproduction thus saving power and reducingwear. This will further save maintenance costs. Reduced maintenance combined with its highefficiency and reliability are strong points infavour of the gearless drives.
Even though gearless drives is a well proventechnology (mills, hoists etc.) it is relatively newin conveyor design. Takraf, in partnership withABB, has integrated features within gearlessdrives which have been standard features forconveyor drive systems for a long time forexample ease of alignment and ease of drivechange. The aim has been to reduce the amountof work in the field to an absolute minimum sothat a faulty drive can be simply replaced andrepaired in the shop. In order to accomplish this, the motor ismounted on a special base frame. This alsoallows the use of standard pulleys another important feature. The configuration of the direct drive unit can induce very significant forces into the pulleys which have caused considerable problems with pulleys in the past. With the Takraf design this has been eliminated.
The company says that its innovativeapproach has produced a reliable and easy to maintain drive concept combining proven technology with state of the art direct drives. Particularly the long tunnel conveyor has been designed to minimise its running resistance by ensuring accurate alignment through special conveyor frames and the use of low running resistance rubber compound for the belt.
The two steep inclined conveyors, which intheir final stage will be both equipped with four2,500 kW drives, presented some challengesparticularly regarding the service of the idlerrolls along the conveyor run, which is mainly intunnels. With heavy idler rolls manual handlingis not only difficult but carries a high risk ofinjury for the maintenance personnel. For thisreason Takraf has developed a unique system toservice these steep conveyors. A specialmaintenance cart straddling the conveyor hasbeen designed to minimise the tunnel crosssection. It is equipped with a small service craneand runs on rails along the entire conveyorlength. The crane is fitted with special liftingframes which pick up the rolls and help to placethem in position. The maintenance personnelonly need to manipulate the rolls, the weight istaken by the crane. The cart can carry sparerolls, all required tools and up to four people. This makes idler roll changes a safe and easytask. Special attention has also been paid tosafety with independent and fail-safe brakingand clamping systems.
Heap leach operations continually seek greatercapacity, continuous material flow, and reduceddowntime. In any application, these challengesare ongoing top initiatives, particularly due tothe complexity of stacking plans. Materialhandling equipment must be highly mobile andextremely flexible. And, for optimumperformance, more and more operations areusing integrated conveyor systems, which canbe custom-engineered for the specific paddesign. The speedy payback from the latter is measured in more tonnes per move, larger leachpad footprints and increased profitability.
Because every heap leaching operationmaintains a specific process with uniquecharacteristics, mines are far more likely toimprove efficiency with a customised andcomprehensive material handling system,explains Jarrod Felton, Vice President ofEngineering for Superior Industries, amanufacturer of mine-duty conveyors,components, and integrated systemscustomised for small-to-large heap leachoperations; and suitable for valley fill pads,billiard table pads, and advance or retreatstacking.
Felton says that an integrated heap leachsystem is comprised of a core group of minedutyconveyors, with the customisation of thesystem being applied with various belt lengthsand widths, belt speeds, and load areas; as wellas choices in hoppers, mobile tracks, controlsystems, electrical components, and the totalnumber of jump or grasshopper conveyors.This strategically selected system of machinesand machine attributes ensures smooth materialtransfer and far greater efficiency over that ofolder, conventional methods.
He explains that currently many heap leachmining operations work in a manual radialstacking mode. Operators will move the radialstacker with a loader to a given location, leavingit to stack there while they perform othermaintenance duties. Later the operators returnto either fill in holes or move the stacker to thenext location. This typically results in sawtoothpile tops, which are not ideal forirrigation, he says.
Alternatively, automated heap leachconveying systems are programmed to stack perdesired lift specifications. The core of such asystem could be the mine-duty TeleStackerconveyor, which is engineered with an internalstinger conveyor that maintains constant motionalong a cell, distributing material evenly toachieve a flat top to each heaped pile, whilealso piling more material per move. Its longerstinger conveyor, over that of conventional radialtelescoping units, allows for greater flexibility incomplex valley fill applications, says Felton. Heexplains that the conveyor is equipped with theFD Series Axle assembly, a technology thatallows a quick transition from radial to linearmode, enabling movement along the leach padcell centreline. Also, the unit features thepatented FB Undercarriage support system,which is constructed of durable steel and atubular braced structure that prevents anytwisting and shifting. This level of stability isrequired for the uneven ground and the constantmovement typically seen in the heap leachenvironment, he stresses.
As to additional mobility options, Felton saysthat operations may use radial travel tracksand/or a track-mounted mobile pivot base inconjunction with the telescoping conveyor. Radial travel tracks are a cost-effective methodto gaining optimum flotation and traction. Whencombined with the mobile pivot base,operations can achieve free-ranging onsite andtransfer point mobility as well as radial travelcapability all while reducing the need formultiple trucks and loaders, he says.
The Horizontal Index Conveyor (HIC) canIntegrate with the telescoping radial stacker. The HIC is a fully-skirted unit with a frame thatmounts to the stacker. For greater heap leachsite mobility, the track drive on the unit isdesigned to move itself and the radial stackeralong the cell centreline and for maximumflexibility, the HIC can be fed at any point alongthe length of the conveyor, says Felton. Headds that when combined with portable jump orgrasshopper conveyors, the HIC minimises thefrequent removal or adjustments of the jumpconveyors along the material transfer line. Ultimately, the combined mobility andflexibility of the HIC is key to building largerleach pad footprints, he says.
Next, Felton explains that a horizontal feedconveyor runs perpendicular to both the HIC andthe grasshopper conveyors. It transfersmaterial from the grasshopper conveyor to theHIC to maintain a consistent, steady materialflow, he says.
Built in standard lengths of 30.5 m (100) orengineered in custom lengths, multiplegrasshopper conveyors comprise a substantiallength and are combined consecutively totransfer material to the stacking conveyors. Felton says that retreat stacking will move inincrements of the grasshopper conveyor lengthby removing one at a time, while advancestacking requires the insertion of a jumpconveyor upon moving forward. For very largesystems, there are super portable grasshopper conveyors that range from 65.5-76.2 m (215-250) in length.
Operations can also utilise a tugger, which isa self-contained and tracked mobile pivot base,to move grasshopper conveyors into place. Itcan also be used as a single point axle on a horizontal feed conveyor, says Felton. He also notes that the companys new Trailblazer Portable Groundline Conveyor can be used to replace some the grasshopper units. This gives the system the advantage of fewer transfer points and electrical connections, and lesser move frequency, he adds.
While a total systems approach to heap leachconveying may seem an unwieldy proposition tosome operations, Felton stresses thatadaptability is made easier when the systemsprovider also takes a total approach to thedesign/build factor. Today its common formanufacturers to sub-contract to others for bothlarge and small components. At Superior, wemanufacture all our components and conveyors,and engineer our systems as a whole to ensuresuch things as smooth material movement at alltransfer points as well as the necessaryelectrical integrity required for the integration ofmultiple conveyors, for example. Our approachalso allows greater control over lead times anddelivery, he says.
From system installation through startup,Felton says that his team provides onsiteassembly and training. This ensures safeoperation and allows the crew to experienceproductivity right from the start.
Lastly, Felton points to the fact that SuperiorIndustries was founded and built on the premiseof making conveyors mobile, and minimizing theneed for costly loader, dozer and haul truck use. So it is no surprise that we are drawn to theheap leach mining market as it has one of thehighest requirements for mobility, he says.
Thor Global has delivered a ThorLoPro low=profile portable radial telescopic conveyor to agold heap leaching application in Mexico. Here,crushed ore is conveyed from two separatecrushing plants into a surge pile that feedsmultiple transfer conveyors, a bridge conveyorand finally the LPT140x42-1200, 42.7.m by 1,050mm low profile telescopic stacker.
The company says the LPT140 fits perfectlyinto the sites existing low profile bridge orindexing conveyor via a rotating pivot pinsystem. Thor Global designed a customremovable fifth wheel pin to accommodate thisunique operations mode anchoring system. Thepatented low profile design has the addedbenefit of preventing spillage due to the factthat the feed point height remains constantwhile the conveyor is being raised and lowered. Dual radial wheel drives was an essentialoptional feature for this application in order toovercome the inherent difficulties of operatingover several layers of previously stockpiledmaterial.
Thor Globals patented push-down axles areinstrumental in providing a seamless liveoperation for this application. This optionalfeature allows the operator to move thetelescopic conveyor multiple times withoutshutting down any belts in the conveyingsequence. As the push-down axles are engagedthe radial arms rise off the ground, whileremaining in their fully extended radial mode. The bridge conveyor then pulls the telescopicback into its next position. During this entiretransition, material continues running off thebelts, non-stop.
Twiflex, part of Altra Industrial Motion, hasintroduced a new disc brake for mining conveyorapplications. The VBS modular brake featureslarge pads and IP65 protection, making it idealfor high speed conveyor drives. The brake alsobenefits from Twiflexs Parked Off safetyfeature; the only system of its kind to allowcompletely safe maintenance and pad removal,the company says.
This new modular disc brake complementsthe existing range of conveyor brakes. The VBSis a fail safe, springapplied hydraulicallyretracted disc brakecalliper which consists oftwo modules mountedeither side of a centralmounting plate. Intendedfor use on high speeddrives on downhillconveyors the brake useslarge pads (10,283 mm2)for high thermal capacityand is fully sealed againstmoisture and dirt ingress.
Steve Powell, ProductManager for Twiflex,comments: The brake isinstalled between the motor and gearbox toprotect the motor against overspeed conditionswhen there is a mechanical failure in the drive. The VBS is easy to install and is fullyinterchangeable with most brakes on the marketwhich makes swap-over extremely quick. Theadded benefit to the VBS over other brakes onthe market is the Parked Off feature whichmakes maintenance work far safer thananything else on the market.
For many years much has been made ofsafety features in industrial disc brakes, withmanufacturers claiming to provide safety lockout during adjustment and pad replacement. With the exception of the Twiflex Parked Offfeature, all of these designs use a mechanicallockout system which utilises a nut and centrebolt arrangement. This method relies on theintegrity of the nut and bolt to hold the springforce; if this fails then the brake will close,potentially causing extremely serious injury.
In Parked Off the disc spring load andhydraulic pressure in the Twiflex design arezero, meaning the VBS has no stored energy andtherefore completely safe for maintenance / padremoval. The position can quickly be achieved inthe field with basic tools making the brake 100%safe without reliance on mechanical lock out. This feature also allows the brake to be installedwithout the need for hydraulic pressure.
Powell continues: We always try to consider the real world problems faced by engineers in the field when designing our latest products. I believe that the Parked Off feature represents a real and unique step forward in personnel safety.
South African conveyor equipmentmanufacturer Melco, which supplies modularconveyor structures for underground mining,has expanded the reach of its products intomore than 75 countries worldwide. MelcoManaging Director Gavin Hall: Melcospecialises in the design, manufacture andsupply of conveyor idlers, rollers, motorisedpulleys and supporting structures.
Melco has been a member of the Rulmecagroup of companies since 2006. Almost all ofRulmeca and Melcos activity involves thedesign, manufacture and sale of idlers, rollersand motorised pulleys for bulk materialshandling applications, notes Hall. As a group,we have chosen to specifically focus on this corebusiness, to ensure that we remain experts andleaders internationally, without being distractedby non-core activities.
As part of its value-added service andcommitment to complete customer satisfaction,Melco Sales and Marketing Director, CraigWarmback points out that the company hasestablished the Melco School of Belt Conveying,which is dedicated to promoting the safe andefficient use of conveyor systems.
Rulmeca reports that Hutchinson Salt Corecently replaced the 20-year old drives on itsstorage shed feed and take-away conveyorswith Rulmeca Motorized Pulleys at the deep saltmine in Hutchinson, Kansas. Reliable plantproduction was in jeopardy because the originalexposed motors, gearboxes, pulleys, and pillowblocks were near the end of useful life. Thecorrosive effects of handling raw salt withelectrical and mechanical components are wellknown.
Hutchinson Salt decided to replace theexposed drive systems with hermetically-sealedinternally-powered drives because they wereaware of the Motorized Pulleys effectiveness inresisting corrosion. Specifications includedstainless steel end housings and shafts, specialpaint, regreasable labyrinth seals, and solidceramic lagging bonded to the pulley shell.
Based on Rulmecas recommendation,Hutchinson Salt changed the drive on the 135 mlong storage shed feed conveyor from a single30 kW head drive to a dual drive, consisting ofa model 400M at 15 kW with a 2 m/s belt speedat each end of the conveyor. This accomplishedtwo things. Firstly it eliminated problematic beltbounce and material spillage at the dischargetripper, as shown in the photo, and secondly itenabled one spare to back up the entire shedhandling system because the shed take-awayconveyor required a 15 kW drive with a 2 m/sbelt speed.
After using the Rulmeca Motorized Pulleys for a couple months, Harold Mayo, Hutchinson Salt Co representative said, We are perfectly happy with the Rulmeca Motorized Pulleys now. The shed conveyor, as of today, is functioning better than ever. It is as close to perfect as it can possibly be.
Hutchinson Salts experience is typical ofproducers of corrosive salt, phosphate, potash,and fertiliser who have invested in RulmecaMotorized Pulleys. For example, Cargill Deicinghas had numerous Rulmeca Motorized Pulleysin service at its deep salt mine in Avery Island,Louisiana since 2004, from the small 15 kWmodel 500 up to the 55 kW model 800, withcorrosion resistant paint, regreasable labyrinthseals, and solid ceramic lagging.
Rulmeca is constantly seeking opportunitiesto solve customer conveyor drive problems,such as corrosion and belt bounce. Anotherexample of a belt bounce problem is at theBuzzi Unicem plant at Pryor, Oklahoma. Whenthe plant replaced a single head drive with adual (head and tail) drive system on its 167 mlong tunnel reclaim system in 2011, they alsoeliminated more than 1 m of belt bounce andsubsequent belt damage during empty beltstart-up in the conveyors concave curvesection. In fact, since it provided 360 insteadof 180 of belt wrap, the dual drive configurationreduced slack side tension by 1 t and enabledthe plant to re-use the trhree-ply belt, in spite ofthe fact that drive power was increased by 33%.
David Brown showcased the improved CXseries of dedicated conveyor drives earlier thisyear at Coal Prep in April 2013. The companystates the CX series offers a design dedicatedto conveying applications without compromiseand offers superior performance in comparisonwith competitors standard general purposegearbox offerings. The advanced technologies of the CX seriesprovide key product solutions for miningoperations, including:
Mark Hollingworth, Director Mining at David Brown said: Weve had a great reaction to the CX series from the mining industry and we strongly believe that it represents the most highly optimised solution for conveyor drives on the market today. It has already been proven to be extremely reliable and low in maintenance in very demanding environments and stands to make a significant and positive impact in mining operations anywhere in the world.
Customers choosing CX series conveyordrives will also benefit from a new three-yearextended warranty package 3X. The 3X isavailable for any gearbox brand and model even those of competitors repaired by DavidBrown and provides access to David Brownsglobal network of service and repair centres forspeedy local service (IM, March 2013, pp72-74).The 3X package also covers new installations ofgearboxes designed and manufactured by DavidBrown.
Gearboxes will be installed, commissionedand maintained at regular intervals by aspecialist David Brown service engineer underthe warranty, a warranty that includes the optionto install CMaS, a remote conditioningmonitoring system, which gathers criticalinformation while the gearbox is in operation,warding off the risk of unexpected failure.
Stieber Clutch launched its new RDBK loadsharing, high-speed, releasable backstop at thisyears Hannover Messe. This compact producthas increased torque capacity compared toconventional designs, which helps avoid theover specification of gearboxes to meet largeoutside diameter requirements of somebackstops. In the event of a blockage, belt jamor overload, the RDBK allows for a controlledrelease under load and is able to rotatebackwards for maintenance and clearing work,unlike many other designs that offer limitedreverse rotation after being engaged.
In most large conveying applications,backstops are installed onto the gearbox toprevent the conveyor from rolling backwards inthe event of a breakdown. To satisfy customerdemands, many backstops now include loadsharing/torque limiting and releasable functionswhich help to reduce downtime once thebackstop has been engaged.
However, to cope with the high torque loadstheir design footprints are often quite largewhich means oversized standard gearboxesmust be specified for them to fit. This cannegatively affect the cost and overall efficiencyof the gearbox. Traditional backstops can alsomake repairing the fault extremely awkward. While they prevent any immediate damagebeing done by uncontrolled reverse rotation,they also prevent the conveyor from being easilyunloaded prior to maintenance. Even designswhich allow for controlled release only provide asmall amount of reverse rotation.
Built on many decades of experience ofmanufacturing backstops for demandingconveying applications, Stieber Clutch hasdeveloped a new, compact backstop designwhich allows the correct sizing of gearboxes aswell as offering reverse rotational capabilitywith a simple hand-operated hydraulic ormechanical release. The RDBK is a centrifugallift-off, sprag-type backstop with an internallimiter which is designed for use on the highspeed or intermediate shaft of the driving unit inmulti-drive systems, such as on large inclinedconveyors, where two or more backstops sharethe reverse load.
With a maximum torque capacity of 170,000Nm the unique, compact design gives it up to3.5 times more torque capacity thanconventional designs of similar sizes; with up to15 times more energy dissipation. To make surethat it remains functional after long periods ofinaction, the friction linings work in an oil bath,providing a consistent coefficient of friction evenafter long periods without engagement.
The release function allows the tension of a jammed belt to be released through an internalhydraulic system. The release is performedusing a simple hand pump to actuate theinternal hydraulic cylinder; progressivelyreleasing the backstop (a mechanical alternativeis available). When the oil pressure is released,the backstop is automatically re-set to theoriginal slipping torque. The operation can becontrolled and halted at any time, helping toboost productivity. Where multiple backstopsare employed, these can be linked and operatedsimultaneously from a centralized controllocation.
Fenner Dunlop Engineered Conveyor Solutions in the UK says it has led the way in the development of fire retardant conveyor belting for underground mine use since back in the 1950s, its PVC impregnated solid woven belt being one of the key factors in mine safety over the last 60 years. Since then significant changes have taken place, both in terms of more stringent safety requirements and a greater demand for heavier duty belts to meet ever increasing production needs.
As Sales Director Jim Jones points outaround the world today we are seeing greatpressure on mines for optimum output withminimal downtime but also, at the same time, amuch greater emphasis on miners safety whichwe wholeheartedly support. Our principles arebased on the premise that an undergroundconveyor belt should never be the cause of afire, should be very difficult to ignite and, if thebelt is ignited from an external source, shouldnever propagate the fire.
Following extensive research anddevelopment carried out by its in-house team oftechnical specialists, Fenner Dunlop UK hasdeveloped a new heavy duty belt for its solidwoven range Fenner Dunlop Type 18000(tensile strength 18,000 lb/in or 3,150 N/mm),hitherto a tensile strength that could only beachieved with a steel cord belt.
The development of a solid woven belt tomeet this tensile strength was one part of thechallenge although the most difficult aspect forthe team was to design a belt of this strengthwhich could also meet the required globalunderground fire safety standards. We knowthat the steel cord belts that Fenner Dunlopmanufacture at various plants around the worldcan easily handle the tensile requirements butthese are generally not able to passunderground safety standards due to the steelcables used in the carcass added Jones.
We are therefore extremely pleased toannounce that we have achieved Europeanapproval to the underground safety standard EN14973 Class C1 for both PVC and rubbercovered Type 18000 solid woven belt, the mostdemanding safety standard for underground use. This belt, along with all others in the Fenner Dunlop solid woven belt range, is certified to Class C1 and can therefore be used safely underground, in potentially explosive environments, without the need for secondary fire safety devices on the conveyor.
To secure this approval, the belt had to passdemanding tests on flammability, gallerypropagation and, perhaps most importantly,drum friction. It wasthe introduction someyears ago of the drumfriction test (whichsimulates a stalledbelt and continuallyrunning drive drum)that has arguablybeen the majorcontributor toconveyor belt firesafety undergroundin recent times.
ASGCOs ImpactCradle Beds are(patent pending)designed to provide protection to conveyorbelts from impact damage from large rocks,tramp metal, roof bolts or bucket teeth thatcan put a stop to operations. The modularstyle impact beds provide impact protectionfor the conveyor belt, as well as a tool to helpcontrol spillage in the conveyor-loading zone. The Impact Cradle Beds support the conveyorbelt across the entire width using ASGCOsunique semi-U-shaped design that eliminatesany unsupported areas between the rollers orbars on traditional impact idlers or traditionalimpact beds where damage can occur in theidler junction points. The cradle beds consistof a heavy duty frame with removable (slide-inor slide-out) sides and centre sections forease of installation and maintenance.
The new ConquestXP primary crusher beltis backed by the power of FortressTechnology, an innovation in rubber compounding and reinforcement technology. ConquestXP is built to excel in impact andpuncture resistance. Including one ply 330, oneply440, two-ply 660 and two-ply 880, andavailable with Goodyear Engineered Productscompounds like Defender, Stacker, Survivorand Global X, this belt is ready for anythingyou can throw at it, the company says. ConquestXP conveyor belts are designed towithstand the harshest above-ground beltingenvironments, developed using intensecomputer modelling and finite element analysis(FEA) software, extreme testing and backed byover 100 years of innovative rubbercompounding research. It is designed forprimary crushers, secondary crushers,mainlines, pit belts and many other high-abuseapplications.
Veyance says the new dual layer twill fabricgives ConquestXP improved load bearing andimpact resistance. [It] has industry leadingimpact resistance. Loading point impact damagecan be a major cause of belt failure. Designengineers used an enhanced dynamic impacttester to simulate loading impact force and itseffects on belting.
The dual layer twill fabric design enableshigh transverse tear strength. This minimisestears that result from material punctures as wellas edge tears from misaligned belts. Scrap metal or debris often get hung up inthe structure of the conveyor, causingequipment damage and slits or cuts in longsections of the belt. Our fabric design helpsdislodge and expel foreign objects and containrips to a small area.
Germanys ContiTech Conveyor Belt Group isstrengthening its conveyor belts business forindustrial applications with the acquisition ofMetsos industrial conveyor belt operationsbased in Helsinki, Finland. Thetransaction includes a production plant inKalkku, Finland, where ContiTech will continueto manufacture conveyor belts for use in theminerals industry. ContiTech also acquires therelated sales and service locations in Finland. Intotal ContiTech will take over approximately 130Metso employees. Both sides have agreed notto disclose the purchase price. Transfer of thebusiness is scheduled for Q4 2013.
The acquisition strengthens ContiTechsindustrial business and is the perfectcomplement to the Conveyor Belt Groupscurrent range of industrial conveyor belts andspecial belts. Furthermore, weare also improving our marketpresence in northern Europeand optimising the structure ofour production sites, saysHans-Jrgen Duensing, Head ofthe ContiTech Conveyor BeltGroup business unit. Ourobjective is to continue andfurther develop activities at theplant in Finland and gainaccess to new customer groupsin the Scandinavian markets. In 2010, ContiTech took overbusiness activities involvingFlexowell and Pocketliftconveyor belts from Metso and has since thensuccessfully expanded business in this area.
Conveyor Belt Monitoring (CBM) notes thattogether with condition based maintenance,planned maintenance comprises preventivemaintenance, in which the maintenance event ispreplanned, and all future maintenance ispreprogrammed. Planned maintenance shouldbe established for every item separatelyaccording to manufacturers recommendation orlegislation. The plan can be based on equipment running hours, date based, or distance travelled. A good example of condition based maintenance in conveyor belts is the amount of damage a belt suffers as the warning sign before it is repaired or replaced, but how do we gauge these warning lights if there arent enough warning lights? A combination approach to monitoring internal damage and external damage is needed if real savings are wanted.
Interestingly, downtime costs recentlysurveyed on one particular mine were estimatedto be A$130,000 per hour. We all like to savemoney but we can clearly see that savingdowntime can pay monitoring systems back overand over again. Comparing simply outage timeinspecting a belt at A$130,000 per hour doesntseem sensible; even if its only an hour pershutdown, say every two weeks, it adds up toover A$3 million/y in lost revenue. Installing a low cost solution monitoringsystem will save a lot of money.
An innovative vision detection system, CBMsBeltspy, has been designed to inspect conveyorbelts for damage that could lead to catastrophicevents. Comprising of a single workstation, located in an office or control room, this system allows the operator to perform an inspection of the conveyor belt covers by visually analysing high resolution images anywhere along the conveyor belt. The system can be configured to inspect either carry or pulley covers, or both.
Beltspy captures the image while the conveyor is in production allowing the operator to inspect damage and identify repairs without the need to stop the belt saving valuable dollars without downtime. The system employs proprietary processing algorithms to automatically detect and flag clips, splices, damaged conveyor belt surfaces and belt edges. The system maintains precise conveyor belt metrics relative to reference location. The locations of all event distances are stored by the system thus providing instant access to event images. Sequential conveyor belt browsing is also available.
Inspecting the internal condition of theconveyor is, for obvious reasons, difficult andbasing repairs solely on external diagnosis canbe costly as there is no need to replace belt if theinternal integrity is intact. Therefore internalcondition monitoring is a prime way to savethousands of dollars.
24/7 monitoring of the steel cords isimperative and can provide immediate securityagainst catastrophic damage and limit theamount of spliced repairs needed. Diagnosis ofthe cords can determine broken cords, cordcorrosion and splice anomalies leading to splicefailure. One of the worst fears for a site is beltingcoming apart and slipping down a drift ordamaging structure, or worse, human injuries. The cost of downtime and clean up is devastatingto bottom line profits. 24/7 Steel Cord monitoringalso offers (DED) Disastrous Event Detection toshut the belt down in the event of any cordsbroken bringing the integrity of the belt intoquestion. So immediate temporary repairs can bemade enabling the belt to perform until the nextplanned shutdown. Another unique feature to the24/7 cord scanning system is the ability to autostop a particular portion of damaged belt to thepre-designated repair station. This saves valuabledowntime by not overshooting the repair stationand having to cycle the belt again.
Phoenix Conveyor Belt Systemshas launched what it describes asa revolutionary conveyor beltmonitoring system, thePhoenoguard PX. It is an all-for-one24/7 device, which detects any deficiency of amoving conveyor belt inside (-> steel cords,textiles, splices) and outside (-> rubber covers). Alarms and recommendations are triggered asper the users requirements. Phoenoguard PX automatically detects, inrealtime:
At regular intervals, a detailed analysis of theentire or any specific part of the belt is provided. This notes critical abrasion and wear (thicknessprofiling), and classifies damages including abelt life forecast. The unit is permanently installed and suited for belt speeds of up to 10 m/s. It operatescontactless and is almost maintenance-free. It isa highly reliable and safe technology, Phoenixreports. There are no manipulations of theconveyor belt required. The use of PhoenoguardPX increases conveyor safety, extends belt life,and drastically reduces maintenance costs andthe number of conveyor shutdowns.
Flexco notes that rollers tend to be one of theleast-considered components of a conveyorsystem. In part, this is because individually theytend to be less expensivethan othercomponentsand it is difficult totrack their life andperformance. But a failed or seized rolleris no small matter. It can cause serious problemsfor an operation, from costly belt damage toextended system downtime along with posingserious safety hazards for employees. Withconveyors comprising most of the haulage loadsin this day and age, having rollers that wearlonger and perform better can increase theefficiency of your operation.
The company recently announced the additionof the CoreTech line of rollers to its wide rangeof products designed to maximise belt conveyorproductivity. The nextgeneration of troughingand return rollers is madeof lightweight, highstrength, corrosion- andabrasion-resistantcomposite materials.
Designed to overcomecommon issues with beltconveyor rollers, CoreTechrollers are durable enoughto tackle a variety ofenvironments, featurelightweight construction,require less energy, andemit less noise than steelcounterparts. The rollersprovide the same CEMA(Conveyor EquipmentManufacturers Association) ratings as steel rollers with no loss of functional performance, while providing a longer service life and superior wear when compared to steel.
Not only is the material durable enough toresist abrasion and friction on the surface of theroller, the field-proven seal design offersunmatched corrosion resistance and bearingprotection on the inside of the roller. Thecentrifugal seal also prevents trappedmaterial from damaging the end disk, whichcan result in premature roller failure. Despite the heavy-duty construction andsolid performance, CoreTech rollers are40-50% lighter than steel. In mostcases, a CoreTech roller requires onlyone person to lift, carry, and place,requiring less manpower and increasingproductivity, while adhering to one-person liftinglimits.
With low breakaway mass, the rollers alsorequire less energy or torque to start rotation. This, plus a low running friction, decreases powerconsumption and can contribute to lower electricbills. CoreTech rollers also create far less noise thansteel rollers. The notable difference can make animpact on worker safety and save an operationfrom costly fines associated with noise pollution.
Two global innovators in bulk material handlinghave formed a strategic alliance specifically todesign and manufacture state of-the-art conveyorsolutions for engineered transfer points. Thenews comes from Martin Engineering, a worldleader in making bulk material handling cleaner,safer and more productive, in partnership withCCC Group, an internationally-recognised generalcontractor that delivers construction,manufacturing, design and engineering services.
By the terms of the agreement, CCC willdesign, engineer and install the chutes, withMartin Engineering delivering the transfer pointcomponents, including load zone and settlingzone. CCC will take the lead on all projects, withMartin support during system specification,design, installation and commissioning,explained Martin Engineering USA ManagingDirector Mark Huhn. We will be providingcomponents such as impact cradles, engineeredchute walls and trackers, as well as skirting andsealing technologies.
The primary benefit to customers will be a veryspecific focus on transfer points involving twopioneers in material handling technologies. CCCs focus and engineering expertise in chutedesign will be complemented by Martinsexperience and innovation in product design andservice, Huhn continued.
An innovative Martin Engineering impact cradledesign is protecting conveyor belts andstructures from falling material in loading zones,reducing equipment damage and downtime whilestabilising the belt line to prevent dust andspillage. The EVO CombinationCradle features steel-reinforcedimpact bars and adjustablewing supports to matchstandard troughanglesof 20,35 or 45. To minimise drag ondrive motors, the cradles can beordered with centre rollers instead of centreimpact bars, explained Martin EngineeringGlobal Product Manager Chris Schmelzer. Ineither style, eccentrics built into the supportsalso deliver 5o of wear adjustment, so thealignment between wings and idlers can beoptimised for effective transfer point sealing.
Combination cradles are typically installed sothe bars or rollers in the centre are slightly belowthe unloaded belts line of travel. This helps thebelt absorb impact, but avoids continuous dragand unnecessary wear if the conveyor is runningempty.
Constructed on a base of heavy formed channels to deliver long service life even under severe operating conditions, impact bars are secured with two bolts each, facilitating easy service and replacement. Combination Cradles are available to fit belts from 500 to 2,000 mm wide, and may have as few as four impact bars or as many as 16, depending on cradle size and centre roll option.
Two bar constructions are available: both havesteel or aluminium reinforcement, with anabsorption layer and a sliding layer of UHMWpolyethylene, which delivers a 0.5 coefficient offriction. The first option is manufactured with a50 durometer SBR rubber absorption layer, andhas a service temperature range of -29 to 60C. The second option utilises an 83 durometer urethane absorption layer and has a temperaturerange of -29 to 70C.
Combination Cradles employ MartinEngineerings Trac-mount technology, allowingthe units to slide in and out easily formaintenance or replacement. The modularcomponents are light enough to be removed byone person, without using heavy liftingequipment.
There is also the rugged EVO High SpeedImpact Cradle, engineered to withstand brutaloperating conditions, reducing roller failures andservice requirements. One customer estimatesthat the new cradles paid for themselves in justthe first week of service at the companys copperhandling facility, due to the savings inmaintenance and downtime. Under high-volumeconditions, standard OEMimpact idlers in the load zonesimply cant withstand heavyloads and lengthy drops,costing downtime for repairsas well as the expense ofreplacement components,observed Martin Engineering ServiceTechnician Doug Brown.
The new cradle design only requires oneperson to change the rollers when the time comes, said Brown. The biggest problem solved is the downtime. In the past, when customers have needed to change rollers or frames, they had to shut down the conveyor for an extended amount of time, he explained. Old style frames can be difficult to remove, requiring that maintenance personnel pull the arms down, then jack up the assembly to pull it out.
We wanted something that was slide-in / slide-out, added Schmelzer. These new cradles were designed using Finite Element Analysis, so we could confirm that theyd be strong enough, without having to overbuild them, he explained. We can make it as strong as it needs to be, without adding excess weight, so workers can remove and replace components without using heavy lifting equipment.
The innovative load zone designs elastomerbar suspension system absorbs and distributesthe material load being transferred, greatlyreducing the stress on the idlers rollingcomponents and support structure. One patentpendingdesign innovation is the use ofconnecting brackets near the top of the idlerframe to hold the three rollers together. Thesespecial brackets are designed to allow multiplemodular cradles to be tied together, so that theidlers throughout the entire load zone worktogether as a system.
This cradle is simple to install, and the easyaccess to the centre roller makes themaintenance a one-person job, Brown added. In addition to greater durability, its intentionallydesigned to facilitate service, making the task ofchanging rollers safer and easier.
Richwood recently contributed to theprotection of the assets of a gold recoveryoperation in the western US with its patentedImpact Saddle. The application uses a 2,400mm wide belt, discharging the primary crusher. Lump size often exceeds 305 mm, and productionis regularly at 3,000 to 4,000 t/h. Drop heighthere exceeds 8 m.
The previous impact idlers that were originallyprovided with the system were fabricatedspecifically for this application but had designflaws that prevented the system from beingsuccessful. Richwood says its design addressedthe design and operational flaws, then went on toset new serviceability and reliability levels. Onceinstalled, the system improved belt tracking, beltcarcass and top cover wear life, reduced spillage(from side travel), improved dust control (fromimproved belt support and sealing), greatlyreduced downtime and service calls, andsubstantially reduced overall costs.
Afterwards, Richwood impact and belt supportsystems were installed at every transfer in theplant. Richwood further says Impact Saddle isconsistently successful in the field, even in themost severe applications, because it addressesthe shortcomings of conventional idlers andimpact beds.
The Impact Saddle is a bolt-in replacement forconventional idlers and is distinguished by acurved surface supporting the whole area of beltcontact. Installed in arrays, the Impact Saddlecan replace impact beds or cradles of many feetin length.
Manufacturing of custom designed WebaChute Systems for Assmangs Khumani iron oremine optimisation project (KOP) is wellunderway. Weba has an existing relationship withKhumani having previously installed a number oftransfer points at this Northern Cape (SouthAfrica) operation. The current contract includesthe design of ten chutes and the manufacturingof a total of four chute systems which weredelivered in the second quarter of 2013.
This latest project calls for three designs ofcompletely new chute systems and a fourthdesign that will cater for the interface of a newtransfer point with the existing Weba Chutesystem. Careful consideration was given to thedesign of all four transfer points to ensure aperfect fit. Our team of engineers, who hasextensive experience in designing customisedchute systems and transfer points, leveraged thisknowledge to ensure that the new systemmaximises productivity, says Ted Cruickshank,Webas Projects Manager.
Cruickshank explains that in order to optimisethe circuit, the conveyors needed to be movedaround. This allowed us to use a portion of theexisting Weba system already in operation, whichnot only simplified the installation but alsoadded to the cost savings for the customer. Thetop section of the existing chute was redesignedto accommodate any possible contaminationwhile the sampler is in motion. In order to ensurethat the existing and new chute systems worktogether seamlessly, the design tolerances hadto be perfect.
Weba Chute carefully considers the directionof flow and the velocity of the calculated volumeand type of material in each application, whilealso taking into account belt width, belt speed,material sizes, shape and throughput. In thisinstance, three of the incoming belts are 750 mmwide with speeds of 1.93, 1.57 and 1.71 m/s, witha fourth one being 900 mm wide with a speed of1.71 m/s. The material lump size varies from 8mm to a maximum lump size of 43 mm. The three750 mm wide incoming belts have a maximumcapacity of 500, 600 and 720 t/h onto outgoingbelts of 750 mm wide with speeds of 1.57 and2.12 m/s. The 900 mm wide incoming belt has amaximum capacity of 1,200 t/h onto an outgoingbelt 1,050 mm wide with a speed of 2.4 m/s.
In addition to the four chutes which weredesigned and manufactured, we also received thecontract for the design of five apron feederdischarge chutes and one trifurcated head chute. The five apron feeder discharge chutes have beenspecifically designed to minimise
dust, wear anddirect belt impact when the ore body dischargesfrom the apron feeder. The system is intended toreduce the speed of the materials beingtransferred and this will be achieved by utilisingproprietary techniques and reverse flowprinciples, Cruickshank says.
These contracts demonstrate Khumani Minesfaith in both our design capabilities as well as inthe Weba Chute System. Controlled material flowspeed, due to the supertube cascade effect created by the systems design, results in decreased dust as well as extended life of the belt. Customers benefit from increased uptime and productivity, together with decreased maintenance, Cruickshank concludes.
Kinder & Co says any investment made inyour conveyor skirting system is a wastedexpenditure unless the belt is properly supportedat the loading zone points. The simpleinstallation of belt support is too oftenoverlooked as an unnecessary andovercomplicated piece of conveyor hardware.
The companys K-Sure Belt Support Systemsimply uses the existing idler frames and loadcarrying centre roller, low drag and highperformance polyethylene slide rails replace thewing rollers. The extra support created eliminatesthe belt edge sag and therefore helps your skirtingsystem to work as effectively as it should. Theoutcome is a fully functioning conveyor,achieving its full product potential, to control anyspillage and contain dust leakage. IM
As the production of iron and steel became the driving force of the Industrial Revolution, advanced technologies and solution in these industries like conveyor belting system replaced the traditional method of material handling. Conveyor Belting System in Iron and Steel Industry allows high speed mass transportation of raw materials from one place to another.
The capability to move materials over a long distance, continuously and economically, has made this belting system even more popular in various leading Iron and Steel Industries. This belting system plays an important role in the process of mining, smelting, and transporting of this industry.
India has one of the richest reserves of all the raw materials required for the iron and steel industry, namely land, capital, cheap labor, iron ore, power, coal etc. Due to this, the demand of material handling and transfer system has also increased. Therefore, we have devised top notch quality of conveyor belting systems for these types of industries.