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СЛОВА К ТЕКСТУ WALKING DRAHLINE ESH-14/65

TEXT III: WALKING DRAGLINES

Walking draglines are used in mining industry for open-cut mining (coal, shale, ferrous and non-ferrous metal ores, gold, raw materials for chemical industry, refractory materials, etc.).

Purpose: overburden operations with rock dumping to waste area or onto pit edge. The draglines are capable of transferring rock for large distances. For mining hard rock, complete or partial blast loosening is required.

Easy erection, maintenance and repair, reliability, increased availability of mechanisms, high maneuverability, good cross-country ability, wide technological capabilities guarantee high operating efficiency of the machine.

Draglines reliably operate in the temperature range from -50 to +40°C.

We offer draglines of 13 standard sizes with bucket capacity from 11 to 100 m³ and boom length from 75 to 130 m, incl. 6 design versions with reduced unit ground pressure.

Design features

-the boom is a triangular tubular space truss. The top chord is pre-compressed with force exceeding the working tension. This considerably increases fatigue resistance of the structure, its reliability and service lifetime;

-truck frame and turntable consist of sections connected with high-strength bolts. This reduces erection labor intensity and shortens erection time;

-hydraulic dragline walking mechanism provides for smooth machine movement and high maneuverability. Depending on dragline model, the walking mechanism may feature threeor four-point design;

-the smallest dragline model features four-bar crank-hinge walking mechanism with a DC electric motor;

-depending on the model, the turning mechanism may feature different numbers of planetary or parallel-shaft reduction gear units;

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-dragline models with high unit power feature gearless turning mechanism drive with four, six or eight low-speed motors;

-rotary support with taper rollers and forged rails;

-two operator's cabs permit both right-hand and left-hand control to suit the particular conditions of the excavation area. Cabs comply with the latest ergonomic requirements and provide for state-of-the-art comfort degree;

-automatic centralized lubrication system ensures longer service life time of dragline mechanisms and units with minimal friction power losses while saving lubrication material;

-main units are driven from DC electric motors designed as generator-motor systems with excitation of electric units from static SCRs. The control system is based on solid state elements;

-data-diagnostic system based on microprocessors allows to control dragline efficiency, power consumption, settings, electric equipment utilization and presence of ventilation flow for electric equipment, as well as the temperature of bearings and excitation windings.

СЛОВА К ТЕКСТУ WALKING DRAGLINES refractory materials – огнеупоры

erection – монтаж

cross-country ability – проходимость

reduced unit ground pressure – пониженное давление на грунт

triangular tubular space truss – трехгранная пространственная конструкция из трубчатых элементов

top chord is pre-compressed with force exceeding the working tension –

верхний пояс предварительно сжат усилием, превышающим усилия растяжения от рабочих нагрузок

fatigue resistance – усталостная прочность

threeor four-point design – трех или четырех опорный

four-bar crank-hinge – четырехзвенный кривошипно-шарнирный planetary or parallel-shaft reduction gear units – редукторы планетарного

или цилиндрического типа

gearless turning mechanism drive with four, six or eight low-speed motors

– безредукторный привод механизма поворота с четырьмя, шестью или восемью тихоходными двигателями

rotary support with taper rollers and forged rails – опорно-поворотное устройство с коническими роликами и коваными рельсами

lubrication system – система смазки

minimal friction power losses while saving lubrication material –

минимальные потери мощности на трение, позволяющие экономить смазочные материалы

excitation of electric units from static SCRs – возбуждение электромашин от статических тиристорных преобразователей

data-diagnostic system based on microprocessors – информационно-

диагностическая система на микропроцессорной базе excitation windings – обмотка возбуждения

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TEXT IV: CRAWLER MOUNTED DRAGLINES

Crawler-mounted draglines are mobile machines based on serial open-mine excavators EKG-5A and EKG-12. The machines are intended for mining and overburden operations with rock dumping to dump pit or to transporting vehicles. On customer's request, the machines can be delivered complete with different-size buckets and customized for specific operating conditions.

Crawler-mounted dragline excavators can operate at any small soft rock (sand, clay, marl) opencast mines, at mines where small overburden operations are required, at coal strip mines, at constructional material opencast mines, at gold gravel deposits. The excavator can also be used for digging trenches, constructing canals and dams and operating at technogenic sludge fields.

Design features

-principal steel structures (boom, turntable and truck frame) made of rolled alloy steel, ensure safe excavator operation in any season of the year;

-high-alloy steel used for certain units ensures faultless operation under high dynamic loads;

-bucket geometry ensures high capacity usage and convenient unloading. Bucket nose and teeth are made of manganese steel. That improves wear resistance and increases lifetime;

-rocking head pulleys and guide pulleys prevent cable escape and reduce cable

wear;

-d.c. electric motor designed as generator-motor system with transistor excitation of electric machines and digital control system;

-separate main unit drives increase equipment lifetime and simplify controls;

-ventilated drive electric motor enables continuous-duty operation of mechanisms;

-operator's cab complies with ergonomic requirements. Cab is soundproof with complete overview of head pulleys and guide pulleys as well as working face overview.

СЛОВА К ТЕКСТУ CRAWLER MOUNTED DRAGLINES marl – мергель

technogenic sludge fields – шламовые поля техногенного происхождения head pulleys – головные блоки

guide pulleys – направляющие блоки cable escape – сход канатов

reduce cable wear – уменьшать износ канатов continuous-duty operation – работать в длительном режиме

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TEXT V: TUNNEL BORING MACHINE

A tunnel boring machine (TBM) is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They can bore through hard rock, sand, and almost anything in between. Tunnel diameters can range from a metre (done with micro-TBMs) to 19 metres. Tunnels of less than a metre or so in diameter are typically done by horizontal directional drilling rather than TBMs.

Tunnel boring machines are used as an alternative to drilling and blasting

(D&B) methods in rock and conventional “hand mining” in soil. A TBM has the advantages of limiting the disturbance to the surrounding ground and producing a smooth tunnel wall. This significantly reduces the cost of lining the tunnel, and makes them suitable to use in heavily urbanized areas. The major disadvantage is the upfront cost. TBMs are expensive to construct, difficult to transport and require significant infrastructure. The biggest is built by Herrenknecht AG of Schwanau, Germany to dig the 57 km Gotthard Base Tunnel. It has a diameter of 19 meters.

The first successful tunnelling shield was developed by Sir Marc Isambard Brunel to excavate the Thames Tunnel in 1825. However, this was only the invention of the shield concept and did not involve the construction of a complete tunnel boring machine, the digging still having to be accomplished by the then standard excavation methods.

The very first boring machine ever reported to have been built was Henri-

Joseph Maus’ Mountain Slicer. Commissioned by the King of Sardinia in 1845 to dig the Fréjus Rail Tunnel between France and Italy through the Alps, Maus had it built in 1846 in an arms factory near Turin. It basically consisted of more than 100 percussion drills mounted in the front of a locomotive-sized machine, mechanically power-driven from the entrance of the tunnel. Unfortunately, the Revolutions of 1848 irremediably affected the funding of the project and the tunnel was not completed until 10 years later, by using also innovative but rather less expensive methods such as pneumatic drills.

In the United States, the first boring machine to have been built was used in 1853 during the construction of the Hoosac Tunnel. Made of cast iron, it was known as Wilson’s Patented Stone-Cutting Machine, after its inventor Charles Wilson. It drilled 10 feet into the rock before breaking down. The tunnel was eventually completed more than 20 years later, and as with the Fréjus Rail Tunnel, by using less ambitious methods.

In the early 1950’s, F.K. Mitry won a dam diversion contract for the Oahe Dam in Pierre, South Dakota, and consulted with James S. Robbins to dig through what was the most difficult shale to excavate at that time, the Pierre Shale. Robbins built a machine that was able to cut 160 feet in 24 hours in the shale, which was ten times faster than any other digging speed at that time.

The break-through that made tunnel boring machines efficient and reliable was the invention of the rotating head, conceptually based on the same principle as the percussion drill head of the Mountain Slicer of Henri-Joseph Maus, but improving its efficiency by reducing the number of grinding elements while making them to spin as a whole against the soil front. Initially, Robbins’ tunnel boring machine used strong

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spikes rotating in a circular motion to dig out of the excavation front, but he quickly discovered that these spikes, no matter how strong they were, had to be changed frequently as they broke or tore off. By replacing these grinding spikes with longer lasting cutting wheels this problem was significantly reduced. Since then, all successful modern tunnel boring machines have rotating grinding heads with cutting wheels.

A tunnel boring machine (TBM) typically consists of one or two shields (large metal cylinders) and trailing support mechanisms. At the front end of the shield is a rotating cutting wheel. Behind the cutting wheel is a chamber where, depending on the type of the TBM, the excavated soil is either mixed with slurry (so-called slurry TBM) or left as is. The choice of TBM type depends on the soil conditions. Systems for removal of the soil (or the soil mixed with slurry) are also present.

Behind the chamber there is a set of hydraulic jacks supported by the finished part of the tunnel which push the TBM forward. The action here is much like an earthworm. The rear section of the TBM is braced against the tunnel walls and used to push the TBM head forward. At maximum extension the TBM head is then braced against the tunnel walls and the TBM rear is dragged forward.

Behind the shield, inside the finished part of the tunnel, several support mechanisms which are part of the TBM are located: dirt removal, slurry pipelines if applicable, control rooms, and rails for transport of the precast segments. The cutting wheel will typically rotate at 1 to 10 r.p.m. (depending on size and stratum), cutting the rock face into chips or excavating soil (muck). Depending on the type of TBM, the muck will fall onto a conveyor belt system and be carried out of the tunnel, or be mixed with slurry and pumped back to the tunnel entrance. Depending on rock strata and tunnel requirements, the tunnel may be cased, lined, or left unlined. This may be done by bringing in precast concrete sections that are jacked into place as the TBM moves forward, by assembling concrete forms, or in some hard rock strata, leaving the tunnel unlined and relying on the surrounding rock to handle and distribute the load.

While the use of a TBM relieves the need for large numbers of workers at increased pressure, a caisson system is sometimes formed at the cutting head. Workers entering this space for inspection, maintenance and repair need to be medically cleared as “fit to dive” and trained in the operation of the locks.

Modern TBMs typically have an integrated shield. The choice of a single or double shielded TBM depends on the type of rock strata and the excavation speed required. Double shielded TBMs are normally used in unstable rock strata, or where a high rate of advancement is required. Single shielded TBMs, which are less expensive, are more suitable to hard rock strata.

Urban tunnelling has the special challenge of requiring that the ground surface be undisturbed. This means that ground subsidence must be avoided. The normal method of doing this is to maintain the soil pressures during and after the tunnel construction. There is some difficulty in doing this, particularly in varied rock strata (e.g., boring through a region where the upper portion of the tunnel face is wet sand and the lower portion is hard rock).

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TBMs with positive face control are used in such situations. There are three common types: earth pressure balance (EPB), bentonite slurry (BS), and compressed air (CA). The compressed air method is the oldest, but is falling out of favour due to the difficult working conditions it imposes. Both types (EPB and BS) are clearly preferred over open face methods in urban environments as they offer far superior ground control.

When tunnelling in urban environments other tunnels and deep foundations need to be addressed in the early planning stages. The project must accommodate measures to mitigate any detrimental effects to other infrastructure.

СЛОВА К ТЕКСТУ TUNNEL BORING MACHINE

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