Английский язык в сфере профессиональной коммуникации. Горные машины. Учебное пособие

IV. Переведите текст на русский язык.

HYDRAULIC EXCAVATORS

Whereas dramatic increase in size of cable excavators during the last forty or so years took place with a long-established technical base, the equally significant development of large hydraulic mining shovels and backshoes has been achieved in a relatively short period of time. There are now at least twenty three models of hydraulic excavators in excess of l00 t weight: of these the two largest are around 500t, three are around 270 t, eight are between and 150 and 190 t and the remaining ten are between 100 and 150 t.

Already by the end of 1981 some eight hundred units of this type of machine has been produced and the large hydraulic excavators now challenge and at times replace, the smaller sizes of cable excavators used in surface mining. Although manufacturers in the USA produced hydraulic excavators in the region of l00 t during the 1970s, it was France and German companies which led the industry into the mining field. Japanese, Soviet and larger American models appeared in the late 1970s and early 1980s.

The largest models are the 498 t O&K RH 300, one of which has been operating in the U.K. since 1979, and the Soviet EG-20 of similar weight which was put on test in the USSR around the same time.

Along with a general increase in size of hydraulic excavators for mining operations a number of significant features and trends have recently appeared. Although most machines are diesel powered. Caterpillar and Kamatsu engines are used – electric power is being offered increasingly as an alternative.

Modular construction is employed for large hydraulic excavators as well as draglines. Despite the size of the Marion 3560 its modular form makes it possible to assemble in only five days. This machine also exhibits features found on other models of hydraulic mining excavators. The operator's cab is fully insulated with thermostatically controlled heating and air conditioning radio and tape deck are included as standard fittings. An annuciator panel alerts the driver to potential problems through an electrical sensing system which monitors twenty-three functions.

Modern computer technology has now been applied to this type of excavator: both the Kamatsu PC1500-1 and Mitsubishi MS1600, for example, have on board microcomputers. The computer on the PC 1500-1 controls an energy saving system, and that fitted by Mitsubishi makes possible intricate digging and loading operations by the driver using a single lever at any one time.

No doubt even larger and more sophisticated hydraulic excavators will be employed at surface mines in the not too distant future. There are indications that Hitachi and Komatsu are amongst manufacturers that intend to introduce larger machines: proposals for a 500-600 t hydraulic excavator jointly sponsored in Japan are believed to be under active consideration.

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In 1981 Hitachi gave an indication of one form of highly innovative excavator that could be created when it demonstrated the concept of the UH999. This large hydraulic mining excavator would have a rotating bucket and telescoping dipper arm allowing dual use as a shovel or backshoe without changing equipment. Its cab could be moved hydraulically to improve vision and the crawler could be extended for increased stability.

СЛОВА К ТЕКСТУ

V. Знаете ли вы значение в каждом ряду синонимов?

1.to apply – to employ – to use

2.to allow – to permit

3.to achieve – to perform – to reach

4.although – though

5.to create – to build

6.to exhibit – to indicate – to show

7.to include – to involve – to contain

8.to intend – to expect

9.significant – important

10.to control – to monitor

VI. Прочитайте текст и постарайтесь понять его содержание при

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MACHINERY USED IN OPEN-PIT MINING

Open-pit mining is applicable in copper, iron, coal, limestone, gravel and sand and sometimes in gold, silver, lead, zinc and other deposits. Where general conditions indicate open-pit methods, a topographical survey is necessary to determine the limits and thickness of overburden. Drainage conditions and physical nature of the materials and enclosing rocks are closely studied. From these the lay-out of the pit and the mining and transportation equipment necessary are determined.

Most open pits are in flat topography of moderate relief, some are on hills or mountain slopes; many have natural drainage but others become sumps.

Open-pit operations begin with the removal of the overburden over the area where mining is to start. Pit and stripping approaches are constructed. Both overburden and mineral mining begin from the top downward in successive horizontal benches until the bottom has been reached. Coal pits are usually shallow; stripping and mining are carried on simultaneously, the stripping shovel being sufficiently in advance of mining or coal loading. Thick overburden and thick deposits, sometimes characteristic of copper and iron pits, require numerous benches; many of which may be worked simultaneously.

Mineral deposits and overburden that can be excavated without blasting are sliced in parallel cuts so as to maintain straight loading tracks, which are placed at the side of the cut. Bench heights are limited to shovel reach. On completion of a cut, loading tracks are shifted to a position for the next cut. It is not always possible to maintain straight loading tracks, and curving benches are quite common in large pits.

Surface mining methods have made it possible to mine many deposits that would be uneconomic to develop underground because of the rapid development of many types of large and efficient machinery and equipment. Although the basic concept of an open pit is simple, the planning required to develop the methods for surface mining is very complex.

The grade and tonnage of material will determine how much waste rock can be stripped, and there is often a limit to the pit that is determined by the economics of removing overburden. The ultimate pit limit and the slope of the pit walls are determined by economics, engineering and by the geological structure. Material that is relatively high-grade may be left unmined in some spot extending too deeply beneath the waste.

Mining is usually done by track-mounted electric shovels in the large operations and by rubber-tired diesel front-end loaders in the smaller operations. Scrapers are sometimes used in special situations. Large bucket-wheel excavators used in European coal mines have not been applied to metal mining, because this equipment is best adopted to softer bedded, relatively flat-lying beds.

Haulage is usually done by trucks, although railroads, inclined rails, and belt conveyers have been used. Each of these unloads directly into a primary crusher, and crushed material is stored in ore bins prior to delivery to the mill.

Bench level intervals are determined by the type of the shovel or loader used, and these are selected on the basis of the character of the ore, and the manner in which it breaks upon blasting and supports itself on the working face. Blast holes are

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usually drilled vertically by self-propelled, track-mounted rotary drills. Explosives are loaded in the holes and large volumes of ore are broken in a single blast. Sometimes the drill holes are sampled to help plan the position of the shovels in advance of mining. Blasthole control is especially desirable when exploration data are incomplete as in older pit which have long been mined.

There are three basic stripping systems:

1)a single stripping shovel travelling on the exposed coal seam digs and removes the overburden ahead of it and piles it in the cut from which coal has previously been removed;

2)a single dragline travelling on a bench above the coal strips overburden to widen the bench for its travel way for the next cut and also removes the high-wall bench over which it has just travelled to expose the coal seam;

3)a shovel and a dragline are used in tandem and they travel on exposed coal. The shovel works ahead of the dragline removing the lower bench to expose the coal seam and piling the spoil in the cut from which coal has previously been removed. The dragline removes the upper portion of the overburden to form another bench and casts the spoil. Numerous combinations of shovels, draglines, bulldozers, scrapers, and wheel excavators are possible.

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UNIT XIII. NEW P & H DRAGLINE

I. Ознакомьтесь с новыми словами и словосочетаниями к тексту

“New P & H Dragline”.

II. Прочитайте текст. Найдите основные смысловые части текста.

III. Скажите по-русски, что говориться о технической характеристике новой модели драглайна.

IV. Передайте своими словами содержание текста.

V. Переведите текст, выделяя ключевые слова для его пересказа на русском языке.

СЛОВА К ТЕКСТУ

1.crawler-mounted diesel electric dragline – драглайн на гусеничном ходу

сдизель-электрическим приводом

2.diesel – electric – дизель-электрический привод

3.suspended load – поднимаемый груз

4.dual generator set – двойная генераторная установка

5.the ratio of horse-power to bucket capacity – коэффициент соотношения мощности (л.с.) к вместимости ковша

6.a single pair of crawlers – однопарные гусеницы

7.independent propel motor – индивидуальный двигатель

8.gear train – передаточный механизм

9.a triple row roller bearing arrangement – трехрядное роликонесущее приспособление

10.troublesome hook rollers – ненадежные крючковые (крюковые)

ролики

11.regeneration – восстановление, регенерация

12.to announce – 1. объявлять, заявлять (о чем-либо); 2. извещать,

сообщать

13.to handle – управлять

14.outgrowth – результат, достижение

NEW P&H DRAGLINE

The first 18 cu. yd. crawler-mounted diesel-electric dragline in the industry has been announced by Harnischfeger Corporation. According to the Corporation, the new P & H model 2355 is designed to give the mining industry the mobility and efficiency of diesel-electric drive not presently available in this capacity dragline.

Also manufactured as a fully electric dragline, the 2355 handles a range of bucket sizes from 11 through 18 cu. yds. and boom lengths from 140 through 200 feet. Maximum suspended load is 90,000 pounds and maximum digging depth is

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130 feet. The application of dual generator sets allows the use of commercially available engines and gives the 2355 diesel-electric version one of the highest ratios of horse-power to bucket capacity in its range. Power from both engines can be applied to any and all motions for peak power demands.

The DC motors and generators, as well as the AC motors for full-electric operation, are designed and built by Harnischfeger expressively for mining service and to provide excellent coordination of work motions. In both the diesel electric and the fully electric versions the DC drive system provides a more energy efficient system than the equivalent mechanical drive systems due to a greater potential for regeneration.

A single pair of crawlers provides greater speed and maneuverability for the 2355. Because of crawler length, each crawler is driven by its own independent propel motor and gear train. Thus steering is performed differentially with both crawlers under power and crawler wear is reduced.

Swing is achieved via two independent transmissions driven by vertically mounted DC motors. For upper rotation a triple row roller bearing arrangement gives improved stability and eliminates the need for troublesome hook rollers.

The 2355 modular design permits exceptionally fast field erection.

The P & H 2355 represents an outgrowth of the technology used so successfully on Harnischfeger's line of electric mining shovels.

VI. Найдите в тексте ответы на вопросы:

1.What new model has been announced by Harnischfeger Corporation?

2.What advantages does the new model have? Describe the model according to the plan: a) a range of bucket sizes; b) boom length; c) suspended load; d) digging depth.

3.Why is the use of commercially available engines possible?

4.What provides greater speed and manoeuvrability for 2355?

5.Why is each crawler driven by its own independent propel motor?

6.What does the model 2355 permit?

VII. Прочитайте текст и постарайтесь понять его содержание при помощи данных слов:

ensure – обеспечивать, гарантировать; escape – выпуск, выскальзывание; overview – обзор, видимость;

rocking – качающийся, колеблющийся

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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:

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

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

c)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;

d)rocking head pulleys and guide pulleys prevent cable escape and reduce cable wear;

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

f)separate main unit drives increase equipment lifetime and simplify controls;

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

h)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.

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UNIT XIV. FIELD TESTING AN EXPERIMENTAL DIESEL-TROLLEY TRUCK IN SIBERIAN OPENCAST IRON ORE MINING

I. Прочитайте текст «Испытания дизель-троллейвоза на базе самосвала (БелАЗ-549) при разработке железной руды на Сибирском карьере».

II. Найдите ответы на вопросы:

1.What model has a team of mechanical engineers at the Sokolovski-Sarbaiski dressing complex designed and tested?

2.Enumerate the additional features of a diesel-trolley truck.

3.What for was a special current transformer installed?

4.Describe the stages of the experiment.

5.What are the advantages of an experimental diesel-trolley truck?

FIELD TESTING AN EXPERIMENTAL DIESEL-TROLLEY TRUCK

IN SIBERIAN OPENCAST IRON ORE MINING

A team of mechanical engineers at the Sokolovski-Sarbaiski opencast miningmineral dressing complex has designed and successfully tested a diesel-trolley truck for hauling iron ore.

The vehicle is based on a standard Russian BelAZ-549 truck capable of transporting up to 75 t of ore.

The following additional features had to be provided: a block of starting controlling resistors, a power and relay circuit cabinet aimed at ensuring the transition from diesel traction to electric with power supplied from the overhead contact system, two automatically operated pantographs.

A testing route section was chosen on the main ramp with an 80° 100 gradient,

800 m in length, and overhead power cables 2,750 mm apart.

A special current transformer was installed at the local substation to provide the required 750/1,500 Vdc supply.

A versatile electric scheme was worked out to enable a smooth switch-over of traction motors from a parallel to a series mode.

At the moment when the raised pantographs contact the overhead power cables, a signal is automatically relayed for switching off the diesel-generator and setting in an external power supply. The diesel engine goes on working practically unloaded – just to operate all the basic systems of the truck.

The tests were carried out by stages. At first, a minimal, 750 V, voltage was tried with truckloads, comprising 25,50 and 90% of the maximum, with traction motors running at 450,500 and 550A and the time 250,570 and 290 seconds, respectively. The average speed amounted to 106 km/h. Then all the tests were carried out with 90% truckloads, with traction motors running at 600A and series voltage on each of them varying between 700 and 800 volts.

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At the concluding stage, the amount of diesel fuel was measured for a diesel engine and trolley-truck operation, with all other things equal. It was found that doubling the operational voltage in the overhead power system to 1500 volts and working with 90% truckloads would ensure a three-fold fuel saving.

On the whole, the diesel-trolley truck based on a standard BelAZ 2-549 vehicle has performed quite satisfactorily: no reduction of its dynamic characteristics or maneuverability took place despite an overall increase of its mass by almost 1.5 t.

Resorting to electric traction made it possible for the loaded trucks to run at about 25% higher speeds, as well as to reduce substantially diesel fuel consumption.

COMMENTARY

1.a block of starting controlling resistors – блок пускорегулирующих резисторов

2.a power and relay circuit cabinet – шкаф силовой и релейноконтакторной аппаратуры

3.overhead contact system – подвесная контактная система (троллейная система)

4.а testing route section – опытный участок

5.the main ramp – руководящий уклон

6.a smooth switch-over of traction motors – плавное переключение тяговых электродвигателей

7.with traction motors running at 450,500 – нагрузка тяговых электродвигателей в процессе движения составила 450,000

III. Переведите следующие предложения на английский язык:

1.Дизельный двигатель продолжает работать практически без нагрузки, обеспечивая работоспособность базовых вспомогательных систем автосамосвала.

2.Во время заключительного этапа испытаний осуществлялся замер расхода дизельного топлива в дизельном и троллейвозном режимах при одинаковых условиях.

3.Переход к электротяге дал возможность груженым самосвалам увеличить скорость на 25%, а также существенно снизить потребление дизельного топлива.

IV. Расскажите по-английски об испытаниях дизель-троллейвоза на Сибирском карьере, используя следующие словосочетания:

a diesel-trolley truck;

to be based on a standard truck;

a block of starting controlling resistors; overhead contact system;

a special current transformers; to carry out tests by stages; the average speed;

at the concluding stage;

to ensure a three-fold fuel saving; to reduce diesel fuel consumption.

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V. Прочитайте текст и постарайтесь понять его содержание при

TRUCKS

The Caterpillar 797B is an ultra class mining truck manufactured by Caterpillar Inc. The 797B is one of the largest mechanical dump trucks in the world. This truck is so large that it cannot be driven on highways to the worksite, but must be transported in pieces and constructed there. A single tire of the Caterpillar 797B (the Michelin 59/80R63), costs $40,000, and is 13 feet (4 m) high.

Caterpillar developed the 797 for the tar sands industry. When then former Caterpillar CEO Glen Barton was asked what was the development for the 797 he gave this answer: “tar sands”. In the tar sands field companies like Syncrude, Suncor and Albian have bought many Caterpillar 797s since its introduction. Today the 797/797B/797F is operating in locales such as Chile, Australia, Indonesia, Canadian Tar Sands and the Powder River Basin area of north-eastern Wyoming and southeastern Montana.

The engine in the 797/797B is a 3524B which costs $600,000 and is made at

Caterpillar’s LEC (Large Engine Center) in Lafayette, Indiana. This particular engine is basically a pair of 3512 diesel engines hooked up to form the 24 cylinder 3524B. The 3512 has powered the 150 ton 785, 785B and the 785C since its introduction in late 1984. It is 3,158 cubic inches and is a V-12 diesel. During MINExpo International in Las Vegas, Nevada Caterpillar introduced a new 797F off-highway hauler. This has the C175 diesel which is 4,000 hp and 6,469 c.i.d. which replaced the 3524B in the 797B.

The 797 is equipped with a torque converter transmission coupled to a seven speed planetary gearset gearbox (plus reverse) which is controlled by a computer. The engine delivers the power to a torque converter which is attached to its rear. Then, the drive is transmitted down a propeller shaft to the rear axle/gearbox unit. The gearbox, differential and axle all form one unit. In common with most large trucks, the axle has reduction gearing within each wheel hub to further reduce the speed of the drive to the wheels.

This gearbox configuration is the same as used on an automatic gearbox in passenger cars, except that in passenger vehicles the torque converter and planetary gearbox are a single unit, attached to the rear of the engine. Designing the axle and gearbox as a single unit and the torque converter separate, is unusual and takes place only where circumstance dictates.

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