extreme machines

A new pit, called Siilinjärvi, is being shaped toachieve this doubling of production from this remote site. Contractors are in there now opening itup with a fleet of 'small' Volvo EC700 excavators. In addition, there is a massive pushback in thecurrent void.

The huge volumes of overburden that needremoving are best highlighted by the depth of thefirst ore layer, some 170 to 200m below the surface.That means they need to dig down 10 benchesbefore striking the first ore.

within the Arctic Circle – where three 4100 Seriesmachines are on the fleet.

The machinery fleet at the Aitik mine has gracedthe pages of Earthmovers Magazine many times.The combined efforts of this impressive fleet ofmega-movers is not enough to keep pace becauseEurope’s largest copper mine is getting even longer,wider and deeper. During the past few years almosta billion euros have been spent on new measures todouble copper ore throughputs from 18 to 36 milliontonnes a year. To produce 36m tonnes of ore a yearmeans the crushers need feeding with an averageof 100,000 tonnes a day. Add the overburden to thisfigure and they need to shift a staggering 90 milliontonnes of material a year!

AUGUST 2010 EARTHMOVERS 7

Three out of every four electric mining shovelsworking today come from P&H, of which the1250-tonne 4100 Series is the US giant's

most successful model, being popular in many ofthe world’s largest surface mines. The companyaims to make ten 4100s a year and seems to be ontrack because, since its launch in 1990, nearly 200of them have been built.

The vast majority of European mines are simplytoo small to accommodate these mobile monsters,which stand a tad under 20m tall and 34m long.Very few European muck-shifting sites can fullyutilise an excavator that can shift 6000 to 7000tonnes an hour. One that can is Europe’s largestcopper mine – located in Swedish Lapland and

Extreme machine

GIANTcopper trioExcavators weighing over 1000 tonnes are a rare commodity in Europe but, as Steven Valereports, a Swedish copper mine has just added a third 1250-tonne P&H to its fleet.

The 4100C is P&H’s largest electric mining shoveland this machine at the Swedish Aitik coppermine is the only example in Europe.

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at night I was thinking about what needed to bedone the next day,” he says. “The components hadto be assembled in exactly the right order. Missing abit could have resulted in major delays to themachine starting work.”

The Arctic winter is not the best time toassemble a new machine because the intense coldmakes an already difficult task even harder.“Working with 67mm-diameter hoist rope is difficultat the best of times,” he says. “But when it is frozenit is like trying to bend an iron bar.”

The intense cold and long, dark winter weeksmeant even fitting ‘smaller’ and relatively simpleparts such as the 1.5-tonne track links and securingpins was much harder than normal. But the biggest

single job was to secure the kingpin in the centre ofthe machine. “If you get this wrong on a machine ofthis size then you have a major problem.”

By mid-January, and after nearly 6000 manhours, the 5500 different parts were all in place. Hishard work was rewarded with the enviable task ofdriving the brand new machine down into thebowels of the pit. After spending a few hours at thecontrols, it was time to sign off and hand it over tothe instructors. Several weeks of tests and operatortraining then followed.

The task is simply too big for the current fleet of machines so they have beenforced to invest in even more loading power. It comes in the form of the largestand newest P&H electric mining shovel in Europe – a 4100C. This heavy-metaldigger did not leave its owner with any change from US$20 million!

Fitted with a monstrous 46.8 cubic metre dipper, the bits and pieces for thislatest American-made creation were shipped from Milwaukee to the SwedishPort of Lulea last October. Transported with a police escorted convoy of fourtrucks at a time, it was a massive operation. The $1m dipper, which even emptyweighs 50 tonnes, is so large it needed its own truck. So too did the 23m boom,which tips the scales at more than 66 tonnes. There were many other largechunks of metal, but the 78-tonne revolving frame was the largest singlecomponent.

8 EARTHMOVERS AUGUST 2010

On site, it was critical all large components were scattered in the right orderto ensure easy hoisting by three big 120-tonne cranes. Assembling the jumboMeccano-style pieces kept 20 people fully occupied two shifts a day throughoutthe winter. It was tough work. Even by Arctic winter standards they weresubjected to fierce snow storms. Although temperatures did not drop to the minus52degC recorded during the coldest day of the last 10 years, the thermometerregularly plummeted to minus 25degC.

The project was supervised from start to finish by Glenn Hannu, no strangerto building big machines. In the past he supervised the assembly of Aitik’s othertwo P&H electric mining shovels and Bucyrus 495. He was also in charge ofputting together two machines that recently left the mine as scrap – the only twoDemag H485 excavators left in Europe.

But he admits that given the need to get the machine ready for action asquickly as possible, the assembly of the 4100C was particularly stressful. For sixmonths he was on site every day, including weekends. “Even when I went home

Main Picture and Above: The 4100 is P&H’s mostpopular model. With an operating weight of nearly1250 tonnes, there are around 200 out at workaround the globe.

Above: This 46.8-cubic-metre dipper weighs 50 tonnes empty and costs US$1million. A spare component is in stock at the mine.

Below: The electric supply cable to this monsterminer provides 6600V, enough to power a smallhousing estate.



Joakim Eriksson clearly enjoys operating theshovel. But he also has regular stints on a Cat 980wheeled loader and often drives many of Aitik’s otherlarge machines. “It is not good on the mind or bodyto sit on the same machine every day,” he says.“When I arrive to start my shift I have no idea whichmachine I will be operating. I think this is healthy.”

The loading team always comprises threeoperators for two machines – shovel and wheeledloader. One operator is always on a break. Duringthe day of our visit, Joakim sat on the new 4100Cfrom 2 to 4pm, then had a one-hour break in thebest mine restaurant you will ever dream about,followed by a couple of hours on the Cat 980. Heended his shift with a further two-hour stint on thenew shovel. He said, “I have a great job because Ionly spend six hours a day on the machines.”

Considering its size, the 4100C is surprisinglynimble and easy to operate. There are no pedals.Instead, many main functions are controlled fromtwo newly-developed and easy-to-use joysticks.Machine swing, dipper hoist, handle operation, andopening the dipper’s rear door, are all controlledfrom two levers. Even the horn, which used to be onthe main control panel, is now incorporated into thejoysticks. He said, “It is great they have included somany functions on the joysticks.”

However, these are not the only new features.The camera monitoring system is also brand new.The exterior of the gentle giant is fitted with nofewer than six cameras: three at the rear, one at thefront, one on the left side of the machine, and one inthe 14m x 8m-wide machine room.

The use of so many cameras may soundexcessive but from the operator's lofty position over10m from the ground, these visible aids areinvaluable. Inside the cab, three cameras are linkedto one of two screens. The operator can swiftlyswitch between them.

“They are a great help. Not only do they allowme to see what is going on behind the machine, butthey are also very useful to follow the wheeledloader.”

All three of Aitik’s P&H 4100s are accompaniedby a Cat 980. Think of it in terms of a workerhoneybee cleaning up around the queen. Darting inand out, sometimes between the shovel and truckduring loading, the wheeled loader operator’s job isto ensure the immediate area in front of the benchremains free of any truck tyre-damaging rocks.Also, when the big electric shovel moves, it is the

wheeled loaders’ responsibility to ensure a cleanarea for the tracks to move on.

The shovel and wheeled loaders are in constantcontact by radio, but the cameras are a useful aid.“They provide a bit of extra safety.”

The camera in the engine room is also handy. “Itis really useful for maintenance work whenengineers are inside the machine. If they want toraise or lower the dipper then I can do it safely in theknowledge I can see them.”

The ropes are an interesting feature of allelectric shovels. The boom does not move, but issecured by a series of sturdy 102mm-diametersuspension cables. The only ropes that move areused to raise or lower the dipper, which is securedto the end of the handle. Using the crowd motor, thehandle traverses along a drive pinion by means of arack drive.

As the dipper rises through the bench it canscoop up 100 tonnes at a time, although theaverage is more like 70 to 80 tonnes. It fills one ofthe 218-tonne capacity Cat trucks in less than twominutes in three passes. But the operator must takegreat care to lower the first dipper as far into the

ELECTRIC POWERThe 4100 is the largest rope shovel currently madeby P&H. But there are no massive diesel enginespumping away at its heart. Instead, the yellow cableprotruding from the rear supplies it with 6600V –enough electricity to supply a small housing estate.

Inside the machine room this is transformeddown to 600V AC, and then again inside a convertercabinet to 580V DC. New on the 4100C is that theoutput is then controlled using a digital drive

system, which replaces the previous analoguesystem and offers numerous important benefits.

“Digital drive is not only much faster but alsomore reliable,” says P&H MinePro service engineerCarl Rowley. “It also offers more electric motor control,helping to improve the flexibility of the shovel.”

Instead of hydraulic motors, DC voltage andcurrent powers seven electric motors: two each forhoist, swing and machine travel, and one for crowd.

The rope shovel comes in several different

configurations – 4100C, 4100 XPB and 4100XPC,the last of which can carry a massive 73cu.m dipperwhen working in coal. But they all use the samebasic footprint.

The main difference is the 4100C has two swingmotors while the XPB and XPC have three. “Threeswing motors provide slightly faster and smootheroperation,” adds Mr Rowley.

However, the single biggest change whenmigrating from the A to C series concerns the cab.Described as a Rolls Royce design, it is certainly agood deal quieter than the cab fitted to the mine’stwo other P&H shovels. But as operator JoakimErikkson says, it should be because it is brand new.

It also offers a much larger glass area. This iscertainly handy at the front and especially whenlooking out through the floor when the dipper is fullyretracted and lowered into position ready to takeanother scoop.

The cab is also large enough to install a toiletand washbasin behind the operator. Yes, P&Hactually offers this as a factory-fitted option and it isinstalled to a couple of machines operating in theUS. But the availability of 120V, 220V and 380Velectrical supplies means many mines opt to installother appliances, such as a fridge or microwave. AtAitik the 4100C, as with the two other 4100s,carries a vacuum cleaner so that the operators canclean the floor at the end of each shift.

Nearly 5m long and well over 4m wide and tall, the dipper iscapable of scooping up a Cat 980wheeled loader. When full, it holdsanything from 70 to 100 tonnes.

Left: The massive shovel loads the largestCat trucks in Europe. This 218t capacity793D is one of six brand new haulersrecently delivered to the site.

Right: One of the main differences in the new C Series P&H4100 is the absence of pedalcontrols. Sophisticated joysticks handle themajority of functions.


12 EARTHMOVERS AUGUST 2010

truck body as possible. If the dipper door is opened from a height then thecontents could give the truck driver a massive jolt, and in the worst cases hasbeen known to shatter truck cab windows! The shovel operator must also ensurethe first dipper is emptied on the far side of the truck body. Otherwise the openingdipper door could smash into the nearside of the body.

The operator reckons in a good bench he can load 25 trucks an hour –sometimes 30 – and at best load around 6000 tonnes an hour. But this dependson several factors, such as size and height of bench. Currently working in a 20m-high bench, providing it is well blasted then he can stand in the same position for

as long as two hours. Currently, the benches are quite narrow, and it takes timeto move the machine to a new position. But this will soon change when the toplayers have been peeled back.

But loading at 6000tph needs a constant supply of trucks. This is somethingAitik is currently looking to address. If all its six big loaders are active, then evena fleet of 22 of the largest Cat trucks in Europe is not sufficient. During my visitthree of the big shovels were temporarily out of action, so the 4100C wasenjoying the attention of eight trucks. “I could really do with 10 but this dependsof the haul distance,” says Joakim Eriksson.

P&H 4100A

This 13-year-old 4100A, the newer of the two original shovels, was recently givena major overhaul. After notching up 53,000 hours of operation, the new coat ofpaint is not the only update. Revised in two stages, the first saw the electricalupgrade. After another two months of operation it then trundled to the top of themine for the mechanical overhaul. This included new tracks, rollers, transmissionand drive shafts on the undercarriage.

After removing the dipper, handle and boom, the machine was split at theslew ring. The 800-tonne upper-structure was then hoisted by a series ofmassive jacks, after which many components were renewed. Although theoriginal electric motors were left in place, the machine was changed from ananalogue to a digital drive system.

A new cab and handle were added before it was put back together again.

P&H 4100

The oldest of Aitik’s P&H 4100s started life in Spain in 1992, but was moved toAitik in 2002. It is currently being rebuilt, but there is a lot more work to dobecause numerous cracks have been detected. Some are due to metal fatiguebut the cold winter weather also plays a role. In any case, four weeks ofcontinuous welding are needed before this one will see any more active duty.

Boliden is spending nearly US$9.5 million on updating and overhauling thetwo older machines. The good news is they expect to get another 40,000 hoursof operation out of each one before any further major work is required.

Operator Joakim Erikkson really enjoysoperating this massive shovel. In theright conditions he reckons he can load7000 tonnes an hour.


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