Whilst wheeled dumpers with4WD can cope with quite badground conditions, the slowertracked alternative really comes

into its own on slopes or when very soft andwet terrain is encountered. Rubber trackeddumpers also score when there is the needto minimise ground bearing pressure, such aswhen working on canal, lake or riverbankswhere a heavier point load might trigger aground collapse.

Tracked dumpers with their wide rubberpads tend to cause less ground damage thantheir wheeled counterparts but contra-

rotating tracks making tight 180° turns canquickly churn up the ground and increasetrack wear. And, when working on narrowbanks beside water, continually turning thewhole tracked dumper around after it hasbeen loaded takes time and can adverselyaffect the stability of the bank.

Although most tracked dumpers are rigidframe machines, some units are made with aslew ring so that their whole superstructurecan be rotated through 360 degrees. Thisdesign eliminates the need to turn the wholetracked dumper to face the other way atboth the loading and tipping points in its

material moving cycle. Rotary top tracked dumpers are some 30

per cent more expensive to buy than theirmore traditional rigid frame counterparts. Butbeing able to eliminate the need to contra-rotate the tracks to turn the whole machinethrough 180 degrees at both its loading anddischarge locations, saves time, reducesground damage and saves track repair costs.Safety is also enhanced as the operator’s cabcan always face the direction of travel.

Wide RangeA leading supplier of tracked dumpers in theUK is Cautrac, which started importing usedmachines in the late 1990s directly fromJapan. Since 2001 it has been the UK and ROIagent for Morooka and this Japanesecompany now builds a complete range ofrigid frame tracked dumpers with carryingcapacities from 2.5 to 15.0 tonnes as welltwo 360 degree fully rotating models.

The first rotating top Morooka was theMST-2200VDR which was introduced intothe UK by Cautrac at Plantworx in 2015.This was some five years after other trackeddumper makers stopped producing this sortof rotary machine.

This 2,980mm wide MST-2200VDR weighs16.0 tonnes and can carry a maximum payloadof 11.0 tonnes. It is powered by a Stage IVemissions compliant 186.0kW (250hp) CatC71 ACERT diesel engine and has ahydrostatic transmission with high and low

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The silt from the lake was removed by two Cat excavators and loaded into theswivel top Morooka MST-2200V with its body at 90 degrees to its tracks.

turnaroundNick Johnson reports from a site inHampshire where the advantages of atracked Morooka dumper with a rotatingsuperstructure have been put to good use.

Once loaded, the MST-2200V operator quickly turned the top of hismachine to face forwards and powered away from the excavator.

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ranges to provide maximum travel speeds of 8and 10km/h. The machine’s rubber track padwidth is 800mm and it has a low groundbearing pressure when empty of 35.4kPa.

The largest fleet of MST-2200VDR rotarytracked dumpers in the UK is now operatedby National Tracked Dumper Hire (NTD).This company was established in January2015 as a joint venture between P FlanneryPlant Hire (Oval) and the specialist plant hirerLand & Water Plant. It now claims to run thelatest, greenest and most reliable range oftracked dumpers in the UK.

NTD Director Richard Maclean says thatthe creation of the new joint venture with itsgreater buying power was instrumental inpersuading Morooka to build the MST-2200VDR – its first 360 degree slewingtracked dumper. NTD senior managersvisited Morooka in Japan with the UK dealerCautrac to agree the design and they thenordered the first nine units.

Whilst in Japan Richard Maclean test drovethe MST-2200VDR and suggested detailedimprovements. The resulting units now scoreby having fully certificated ROPS and FOPScabs, a Spillards 360 degree camera system, anincreased capacity fuel tank with more

accessible filler (reached by front mountedsteps) and a hydraulic system isolating device.The NTD machines run on Panolinbiodegradable hydraulic oil and have a greencoloured seat belt secured indication beacon.

One of NTD’s MST-2200VDR machineshas recently been successfully used inHampshire where Land & Water Services hadthe contract to dredge silt from a two-acrelake on a large private estate. This job utilisedtwo 15.5m long reach Cat 320EL excavatorswith 1.4m wide grading buckets – onepositioned in the lake to feed silt to theother, which then loaded the Morooka.

Better Target AreaThe Morooka travelled between the Cat 320ELon the bank along a relatively narrow trackbeside the lake and then through a gate into anadjacent field where the silt was quicklydischarged in a thin layer. During loading thebody of the Morooka was turned at 90 degreesto the machine’s tracks to provide a bettertarget area for the excavator operator.

The body of the MST-2200VDR was fittedwith silt boards to maximise the load of thislow-density material and, after being filled in12 passes, the machine was quickly on its way

to tip its load. Not having to reverse orspragg around at either end of its journeyresulted in a quick cycle time of around twoand a half minutes. Also contributing to siteproductivity and the even distribution of thesilt in the field was the machine’s constantlypressurised pull shut tailgate so it ispractically watertight.

Whilst the right angle turn through the gateto the field resulted in deep ruts, there was noserious surface damage in the field or on thebanks of the lake, as the machine did not haveto turn its undercarriage in these areas. Andthere are also operating cost benefits.

Richard Maclean says: “Our standard, rigidframe, tracked dumpers need to have theirsprockets turned on a relatively regular basisto ensure even wear. But a slewing machinetends to wear sprockets more evenly as themotors drive almost as much in reverse asthey do going forwards.”

Johnny Glover, the Private ClientsDivisional Manager for Land & WaterServices, says that the MST-2200VDR wasideal for this silt-shifting job due to its speedof operation, lack of ground damage and safeforward travel. Having successfully used thismachine on other jobs, he is a big fan ofswivel top tracked dumpers.

Spurred on by an increasing number ofconverts to the concept, Morooka has justlaunched a smaller swivel top model. Due tobe introduced here this summer by Cautrac,the new MST-1500VDR has an unladenweight of 11,500kg and a payload of 7,000kg.It is powered by a 168kW (219hp) CumminsQSB6.7TF engine and it has a maximum travelspeed of 8.6km/h. Cautrac has high hopes forthis smaller brother to the now well-established MST-2200VDR.

For further information on theMorooka swivel top tracked dumpersuse the reader enquiry number below

CIRCLE READERLINK 049

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After reaching the discharge point in the field, the top of themachine is turned through 180 degrees ready to tip the silt.

The design of the body with its silt boards and pressurised rear tailgateallowed a thin layer of silt to be spread on the field ready to be ploughed in.

Being able to rotate the top of the machine rather than havingto spragg the tracks greatly reduces undercarriage wear.

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