Английский язык для горных инженеров-механиков. Учебное пособие

oscillating, and pneumatic conveyors. Wheel or roller conveyors cannot handle bulk materials

Belt conveyors are preferable for carrying coal. The belt runs on a bed of closely spaced rollers positioned to form a flat or troughed conveyor bed. Belt may also be made of such materials as rubber, metal, or open wire. Belt conveyors are only used within angles of 28 from horizontal. Materials feed onto belt conveyors from hopper or from storage facilities overhead and may discharge over the end or, if the belt is flat, by being diverted off one side. Belt conveyors can handle most materials over long distances and up and down slopes. Their advantages include low power requirements, high capacities, and simplicity.

An apron conveyor is a form of belt conveyor but differs in that the carrying surface is constructed of a series of metal aprons or pans linked together to make a continuous loop. The pans, which may overlap one another, are usually attached at each end to two strands of roller chain. The chain runs on steel tracks, movement being provided by suitable chain sprockets. Turned-up edges or wings provide a troughed carrying surface. This type of conveyor is suitable for handling large quantities of bulk material under severe conditions and can operate at speeds up to approximately 300 ton per hour. Apron conveyors are most suitable for heavy, abrasive, or lumpy materials.

Bucket conveyors are constructed of a series of buckets attached to one or two strands of chain or in some instances to a belt. These conveyors are most suitable for operating on a steep inclined or vertical path, sometimes being referred to as elevating conveyors. Bucket construction makes this type of conveyor most ideal for bulk material such as coal, and sand. Buckets are provided in a variety of shapes and are usually constructed of steel.

Flight conveyors employ the use of flights or bars attached to single or double strands of chain. The bars drag or push the materials within an enclosed duct or trough. These are frequently referred to as drag conveyors. Materials can be fed to the conveyor from any desired intermediate point and, by the use of gating can be discharged at any desired point. Dragline conveyor operates on basically the same principle as flight conveyor.

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When they can be used, conveyors are preferred by the engineers because of their reliability and high capacity. Conveyors can move more coal per hour than any other form of transport now in use.

III.2. Find the answers to the following questions.

1.What is a conveyor?

2.What may be the actuating medium for conveyors?

3.What kinds of conveyors are preferable for carrying coal?

4.What kinds of conveyors are most suitable for heavy, abrasive, lumpy materials?

5.What types of conveyors cannot handle bulk materials?

6.What are the advantages of an apron conveyor?

7.Where are bucket conveyors most suitable?

8.Why are conveyors preferred by the engineers?

III.3. Find out the paragraph which speaks on the advantages of belt conveyors.

III.4. Find out the paragraph speaking on the types of conveyors.

III.5. Fill up the table below using the information of the text.

III.6 Give the summary of the text.

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UNIT VI

Modern Methods of Mining.

Rapid Excavation.

I

I.1. Find the meanings of the words from the dictionary.

I.2. Translate the words without a dictionary.

hydraulic, control, group, universal, section, modern, operation, construction, limit, factor, automatic, problem, telescopic, liter.

I.3. Guess the meanings of the words below, minding the similarity of their stems with those in your native language.

unit, equipment, forward, pressure, rate, speed, application, productivity, typically, manually, force, realize, advance, operate, push, water, fluid.

I.4. Translate the following nouns and verbs.

I.5. What does the word “per” mean? Read and translate the following.

100 liter per minute; 40 meters per second; 56 per cent; 65 km per ton; 70 kg per ton; 60,000 per year; 20 kg per square centimeter.

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I.6. Pay attention to the pronunciation of some verbs when “-ed” is added.

I.7. Define the meanings of the derivatives.

I.8. Translate the following sentences containing “as”, and “as ...

as”.

1. As the machine advances it cuts the coal. 2. We mounted the lathe as it was shown in the instruction book. 3. As there were no wells in the vicinity of the construction site, we had to bring water in tank wagons. 4. The strength of this new synthetic material is as high as that of steel. 5. As soon as he finished his calculations we'll begin the tests. 6. It’s impossible to go on with the tests as long as they need it. 7. The problem of speed is as important as the one of saving energy.

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I.9. Revise grammar material “Absolute Participle Construction”. Translate the sentences below.

1. Many mechanized methods are used in coal getting, powered roof support being almost universal in modern coal faces. 2. The mine having been supplied with new scrapers, the productivity increased greatly. 3. Each element in the system of supports plays its part, the general efficiency of the work depending of any of them. 4. The fuel being exhausted, the engine stops. 5. The semi-automatic system having been employed, the higher productivity was obtained.6. The nature and extent of the environmental problems arising from the mining industry are very wide, ground vibrations being the most difficult problem to overcome.

I.10. Revise grammar material “Conditional Sentences”. Translate the sentences below.

1. If the ore is very hard, it will be broken by the blasting. 2. If the designer could develop such kind of machine, the problem would be solved. 3. If you had informed us about the damage in due time, the replacement of the equipment would have been possible. 4. Were this machine more reliable, it would be used for carrying people. 5. We should have considered all the variants, if we had had more time. 6. Unless the temperature rises, the reaction will not be possible. 7. Provided they get all the needed instruments, they will be able to continue the investigations.

I.11. Read and translate text A.

TEXT A. The Powered Roof Support

1.Almost all roof supports used on the coal face are now hydraulically operated. They are operated by merely opening or closing valvets which control the flow of hydraulic fluid.

2.The principle of the hydraulic support is that its two telescopic sections are forced between the roof and the floor by the action of hydraulic fluid under pressure. The hydraulic fluid is non-flammable, being 95 per cent water and 5 per cent oil.

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3.On the coal face it is usual to group several of these hydraulic supports, or props, together into a unit ,called a powered roof support, which is connected to the AFC*.

4.Such “powered” or “self-advancing” roof supports are almost universal in modern mechanized coal faces.

5.The face equipment is advanced during the cutting run of the power loader by four main operations.

1) Pushing or “snaking” the AFC forward by extending the horizontal

jack.

2) Releasing the pressure on the support unit, thus lowering the props. 3) Advancing the support by pulling on the AFC.

4) Applying pressure on the props again, tightening them to the roof.

6.On a 200 m long coal face there may be as many as 200 powered roof support units. Typically they require hydraulic fluid at a pressure of 180 bar with a flow rate of 150 liters per minute to give fast operation of the support.

7.The powered supports are capable of bearing loads of 150-250 tons, depending on their size and construction.

8.One of the limiting factors in the production rate at a coal face is the speed of operation of the powered roof supports. If the operating speed of these supports could be increased it would be possible to get higher productivity. In recent years engineers have attempted to produce a reliable automatic powered roof support.

9.The problem with manually operated powered roof supports includes the length of time; on average it takes about one minute to lower, advance, and set six supports. With semi-automatic supports it takes only a split second to realize lowering, advancing and setting.

AFC–armoured flexible conveyor.

I.12. Answer the questions.

1. What is the principle of the hydraulic support? 2. What controls the flow of the hydraulic fluid? 3. What is the role of oil in the hydraulic fluid? 4. How many supports are usually grouped into a unit in the coal face? 5. What is powered roof support usually connected with? 6. What is the sequence of

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operations in advancing the face equipment during the cutting run of the powered loader? 7. How much hydraulic fluid is required to give fast operation of the support? 8. What factors influence the capacity of powered supports? 9. What is the main factor limiting the productivity of the powered roof supports?

I.13. Find the sentences corresponding to the subject of the text.

1.In surface mines trucks and shovels are mostly used.

2.Several roof supports are grouped into a unit called powered roof supports.

3.Hydraulically operated roof supports are mostly used in the coal face.

4.The potash seam is worked using a specially designed double-drum

shearer.

5.Manually operated roof-supports are not efficient because of low

speed.

6.Processing machines are almost exclusively powered by individual electric motor.

7.Any overburden must be removed by stripping processes before mining begins.

8.The speed of operation of the powered roof supports is one of the limiting factors in the production rate at a coal face.

9.To get some idea of the depth of the deposit it is necessary to put down several deep boreholes.

I.14. Compose as many word combinations as possible.

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I.15. Fill up the blanks with suitable words and word combinations from the box.

valvet, coal face, hydraulic fluid, floor, cutting run, operating speed, props, self-advancing

1. It is usual to group several hydraulic supports on the ... . 2. The opening or closing of ... controls the flow of hydraulic fluid. 3. The increase of the ... of the powered roof supports makes it possible to get higher productivity. 4. Roof support units require ... at a pressure of 180 bars with a flow rate of 150 liters per minute. 5. Two telescopic sections of the hydraulic support is forced between the roof and the ... . 6. Several hydraulic supports or .... are grouped together into a unit. 7. Powered roof supports are sometimes called ... roof supports. 8. The face equipment is advanced during the ... of the power loader.

1.16. Fill up the blanks with the appropriate prepositions.

at, on, of, by, to, under

1. Roof supports are operated ... opening or closing valvets. 2. Valves

control the flow ... hydraulic fluid. 3. A powered roof support is connected ...

AFC. 4. Hydraulic fluid is moved ... pressure. 5. The capacity of the powered roof support depend ... its size and construction. 6. The AFC is pushed forward ... extending the horizontal jack. 7. The support is advanced ...

pulling on the AFC. 8. Typically roof supports require hydraulic fluid ... a pressure ... 180 bar. 9. Semi-automatic roof supports are capable ... realizing lowering, advancing and setting in a split second.

I.17. Complete the sentences with the suitable verbs in Passive.

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6.If the operating speed of the supports to be produced

_______ it would be possible to get higher productivity.

7.In recent years reliable automatic roof

supports ________.

8. Hydraulic supports grouped into a unit called powered roof supports______to the AFC.

I.18. Replace the underlined words with the synonyms from the

text.

1.Generally powered roof support units require hydraulic fluid at a pressure of 180 bars.

2.Hydraulic fluid is forced with a flow rate of 150 litters per minute to give rapid operations of the support.

3.The semi-automatic supports accomplish lowering, advancing, and setting only is a split second.

4.The AFC is advanced by extending the horizontal jack.

5.Four principal operations are realized during the cutting run of the power loader.

6.The problem with manually operated roofsupports comprises the length of time.

7.Hydraulic supports are put into operation by simply opening or closing valvets which control the flow of the fluid.

I.19. Mind different meanings of the word “run” and its

derivatives.

1.I know him to be a good runner.

2.He was appointed to run the new enterprise.

3.When repaired, the engine is running smoother.

4.During the run of the machine fluid is driven without any break.

5.The allocated time ran away.

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6. When testing the machine they left the engine running during three

hours.

7. Things must run their course.

I.20. Look at Fig. 2 and name eachstep, using information of the text

Fig. 2 The cutting run of a power loader.

I.21. Give the summary of the text.

II

II.1. After reading text В say whether each of the two parts describes:

the mining conditions in which the machines work;

the principle of work of several machines or only one;

many different types of machines;

advantages and disadvantages of the machine;

combined work of the two of the machines.

TEXT B. The Power Loader

The heart of the coal face is the powered loading machine. This powerful machine travels along the coal face in contact with the coal, sliding on the AFC, cutting out a strip of coal and pushing the fragmented coal onto the AFC.

The most common powered loader used in long-wall mining is the shearer. This machine has a drum fitted with sharp tungsten carbide-tipped pick which rotates as it is pushed into the coal, cutting the coal in a similar

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