Haul Trucks Mining

Diamonds hidden in permafrost

Posted on 04 January 2021 by Ulrich Heyden, Images by Ulrich Heyden

mtu powers haul trucks carrying diamond-containing rocks.
The Jubilejny open-cast mine has got to be one of the loneliest places on earth. It may be fairly close to the Siberian town of Aichal with its 13,000 inhabitants, but beyond that it's a long way to anywhere. The nearest town is 500 km distant, and you're just 60 km from the Arctic Circle. Over 10 million carats of diamonds are mined in Jubilejny each year with the help of mtu-powered haul trucks. The climate is extremely harsh – for man and machine alike.

Belaz haul trucks with payloads of 136 metric tons rumble their way towards the opencast mine. The Aichal Diamond Combine, owned by Alrosa, has 55 such dump trucks, of which 45 are equipped with 12-cylinder mtu Series 4000 engines. Michail and Yefgeni, two drivers

taking a break from their difficult jobs, say their experience of the engine is very positive. They reckon it runs more quietly and with less vibration than other models, whilst being economical and not susceptible to breakdowns.

The sun shines in a cloudless sky. The hilly landscape has a covering of snow. Quarry stone has been scattered on the snow-covered gravel road to prevent the six-meter-high dump trucks from slipping. The thermometer is showing minus 21 degrees Celsius at the end of February, in fact temperatures here can drop as far as minus 46 degrees during December.

A place of extremes: Diamonds – weighing over ten million carats in total – are mined in the Jubilejny open-pit mine. Located in remotest Siberia, near to the Arctic circle, it's a place where permafrost challenges both man and machine. So far, the miners have succeeded in plumbing depths of 440 m in blasting operations.

The mtu engines are specially prepared for the chilly conditions in Siberia. Because the polar diesel used in this area has a kerosene content of 60 percent, making it much thinner than normal winter diesel, mtu has designed the injectors to be able to cope with the thinner fuel. Louvers in front of the radiator prevent the engine from cooling down. These are always closed when idling during really cold spells. The engine control unit automatically adjusts fuel quantity and injection timing in line with the air temperature. In addition, depending on ambient temperature, pre-injection is used alongside main injection during start-up.

Visit to the control center

In a windowed container right on the edge of the opencast mine, two experienced workers keep in touch via radio, and online, with the haul truck drivers and the men in the shovel excavators. Blasting is carried out on Thursdays and Fridays, when the pit is closed. Excavators push the scree together for transportation. Huge shovel excavators, 19 meters high and weighing 600 metric tons, whose buckets can swallow up to 15 cubic meters, load it onto haul trucks in just a few minutes.

You cannot tell by looking at the rocky cargo just what value lurks within. The dump trucks take the rubble to the treatment plant, where it is dumped into shafts, producing levels of noise nothing short of deafening. The debris is then crushed in huge, rotating drums, and washed in basins. Separation systems detect the diamonds with the aid of X-rays and shoot them out of the rock with compressed air. The final stage has workers picking the diamonds out of the fine rubble by hand.

One metric ton of scree can be expected to yield 0.9 carats of diamonds – 0.18 grams. In 2017, diamonds weighing 10.16 million carats were mined here. The view across the open-cast pit is breathtaking. The mine is two and a half kilometers wide. Blasting and drilling have driven a cone into the earth's crust that is already 440 meters deep and is planned to go to a depth of 720 meters. At the edge of the open-cast mine, a road spirals down into the depths, taking the mighty, six-meter-high haul trucks down to collect their loads of rubble. Viewed from the control center, they look like children's toys. Everything in the mine is running smoothly. There are no traffic jams. The men in the control center follow the haul trucks' progress on their screens running an online mining program. Everything simply has to work smoothly. If drilling or blasting is to be conducted somewhere, routes have to be changed in good time. In summer, water is used to bind the dust to the roads to prevent the engines' air filters from clogging.

 

Rock and rubble: The Belaz dump truck has a payload capacity of 136 tons. But the precious stones only become visible during processing.

Good kindergarten and wide range of leisure activities

The men in the control center are in a good mood. They say they've been living in Aichal for 30 years. The nicest, most relaxing hobby is to go hunting in the taiga woodlands. And their wives? They like the crosscountry skiing, they say, and collecting berries and mushrooms is also popular. In the taiga, however, you have to protect yourself against the swarms of mosquitoes. The company, Alrosa, does a lot to enrich the lives of Aichal's 13,000 residents. There is a very well equipped kindergarten, an ice rink, a swimming pool, a sports hall and a newly built cultural center where choirs and dance groups rehearse.

Retirement at 50

The workers in the vehicle control center say they are both already pensioners, but still have to work because the pension is just 330 euros. In Russia, men retired at age 60 until 2018. There is a pension bonus for Russians living in the far north. An additional bonus is given to people working below 150 meters in open-cast pits. For mechanics in the Alrosa workshops, this means that they used to be able to retire at the age of 55. The two workers in the control center retired at 45 and 50 respectively because they worked in open-cast mining.

The biggest compensation for living in a wasteland is a good wage. The two tipper drivers Michail and Yefgeni earn 1,800 euros a month. They say they go on holiday once a year to China, Thailand or Montenegro. Many also have apartments in warmer parts of Russia – 'on the mainland' as they say in Aichal with more than a hint of irony. As soon as they retire,  and their financial situation permits, most people want to leave Aichal. But there would always be a flow of new, young workers, fleet manager Lapygin assured us: “Good pay attracts people.” Today, 13,000 people live in Aichal. 4,000 of them work in the diamond combine, 1,000 of those in the transport sector alone. The brightly painted prefab buildings in Aichal were not built until the 1980s. Before that, there were only timber houses. And before that, the geologists and construction workers who laid out the town and the open-cast mine lived in tents. Until the 1980s, there were no elaborate medical facilities for childbirths.

Mosquitoes, mud and permafrost

Weather conditions in and around the Arctic Circle are extreme. The ground is frozen for seven months of the year. In summer, the ground thaws up to half a meter deep. Aichal is even more remote in summer than in winter because, traveling by car, you can only get to the airport in Polarnoje and to the city of Mirny, 500 kilometers away, where Alrosa's headquarters are located. People cannot go any further because in summer the roads are

muddy, and Aichal is not connected to the Russian highway network. It is therefore anything but easy to ensure supplies for the town with its three diamond mines and two diamond processing plants.

Spectrometric analysis of engine oil for improved maintenance

The first four 136-ton haul trucks with mtu engines were delivered to Aichal in 2005. “At the time, we sent five people to a coal mine in South Yakutia for training, where mtu engines were in use,” reported chief engineer Andrey Kayukov. At 38, he is one of the younger members of the workforce. The acquisition of an expensive spectometric oil analysis laboratory was a major step forward in engine maintenance, he says. Spectrometric analysis of engine oil is now used to detect metallic particles caused by engine wear. This allows conclusions to be drawn about specific damage to the engine. The chief engineer reports that spectrometric analysis has postponed the general overhaul of the engines by a considerable length of time. A general overhaul of the engine is recommended after 25,000 operating hours. But they now have one mtu engine with 40,000 engine hours, and eleven mtu engines with 33,000 to 38,000 engine hours, which have had only minor repairs, but no general overhaul. Two of the mtu engines obtained in 2005 are still in use. “As soon as we find any metal particles in the engine oil, we have an indication of where the fault could be,” said chief engineer Andrey Kayukov.

Only highly experienced mechanics are allowed to perform service work on the mtu engines. Spectrometric analysis is dealt with by engineers. Due to the eight-hour time difference between Aichal and Friedrichshafen, service personnel in Friedrichshafen is only called upon in absolute emergencies.

In order not to leave engine evaluation to the mechanics alone, a video endoscope is also used: “In a twelve-cylinder engine, we could see metal abrasion in one cylinder. We have decided to install two new cylinder sleeves. Without diagnostics, we would have replaced the entire engine.” “If we run out of ideas, we send the engine inspection files to Friedrichshafen,” he continued. “However, that doesn't happen more than once a year.” He says it is 'not very convenient' to contact mtu because of the eight-hour time difference between Friedrichshafen and Aichal.

In service 24/7

The haul trucks are in operation 24 hours a day, seven days a week. The haul truck drivers work 12-hour days, after which they have two days off. The haul trucks only stand still when their drivers are taking a break. In winter, the engines are not switched off during breaks because it is difficult to restart them in the cold. If they do get turned off, an electrically operated heat source is placed near the engine. “Electricity is cheaper here than diesel,” explained the chief engineer. They order spare parts every three months from mtu's spare parts warehouse in Chimki near Moscow, according to Sergei Lapygin, head of the vehicle fleet. The spare parts are then flown from Moscow to Polarnoye, a town one and a half hours north of Aichal, by the company's own Alrosa airline. That said, cargo planes from Moscow only take off if they are carrying aggregate loads of at least five tons.

 

Engine mechanic Wenjamin Metelski has been servicing mtu engines since 2005. He's proud to report that the mtu engine behind him has clocked up well over 60,000 operating hours.

The engine the two workers are currently overhauling has run well over 60,000 hours, he told us. They have installed a new diesel pump, a new turbo compressor and new high-pressure lines. There are only experienced mechanics working in the repair shop. Sometimes they are assisted by the haul truck drivers. The workshop looks very neat and tidy. Safety regulations are very strict. A cable or tool carelessly left behind can have disastrous consequences, given the size of the components the men have to deal with. Helmets are mandatory, and of course alcohol is prohibited in the workplace. At least it's nice and warm in the workshop. When you leave the bay, there's a cold wind and crunching snow – and the mtu-powered Belaz trucks are constantly going up and down with their valuable rocky cargo.

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