О.А. Ставцева Английский язык. Методические указания и устные материалы для выполнения контрольных работ №4, 5, 6

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monosov in his book «First Principles of the Science of Mining» (1742). He considered the science of mining to be of vital importance to the national economy. The development of the Russian mining school had been greatly affected by that book and other papers dealing with geology and mining.

The most prominent M. Lomonosov’s followers are considered to be A. Karpinsky, B. Boky, M. Protodyakonov. The first of them studied the problems of geological history of the country’s European part. It was him who worked out the theory of organic origin of coal. Boky is known to have developed the analytical method of mine planning. Protodyakonov proposed a new classification of rocks based on numerical coefficients.

At present the Russian scientists are making great efforts to the further development of the theory and practice of both geology and mining. It is very important because the world’s coal production is expected to grow from 4,125 mln tons in 2000 to 7,700 mln tons in 2025.

3. KUZNETSK COAL FIELD

Kuznetsk coal field is unique in the size of its coal reserves, ranks of coal as well as the diversity of mining technologies employed. It gives 39 per cent of the country’s production of coal and for 69 per cent of coking coal.

Kuzbass is known to have more than one century history of coal industry development. There are 25 coal-containing areas in the region but only 17 of them have been or are being exploited. The greatest deposits are located in the Leninsk, Erunakovsk, Tom-Usinsk regions. Geologists suppose the Erunakovsk deposits only to be equal to those of the entire Donbass.

Since the beginning of mining in the Kuznetsk Basin, 5 billion tons of coal have been extracted. Taking into account that the deposits are evaluated by geologists to be about 725 billion tons, this makes less than 1 per cent of the coal reserves. That is, at an annual production of 150 mln tons (even allowing for 50% loss), the Kuzbass coal reserves would be sufficient to cover coal needs for an actually unlimited period of time in future, far exceeding the medium-term forecasts on world fuel sources.

Near half of the deposits are coking coals. Brown and anthracite coals are also available. The coal characteristics are so wide that they can meet the needs of different branches: metallurgy, power engineering, chemistry. The quality of Kuzbass’s coal is said to be the best in the world.

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One of the special geological features of the Kuznetsk Basin is that of great variety and complexity of coal seam bedding. This factor resulted in the necessity of a wide range of techniques to get coal.

4. COAL MINING IN RUSSIA

The Russian Federation was estimated to have as much as 4.4 trillion tons of coal which makes 30 per cent of its world’s reserves. Being one of the leading heavy industries of Russia, coal mining has always been developed together with the country’s national economy. Proper organization of operation requires adequate planning, safety, maintenance, labour force as well as estimation of the coal quality. Hence, a lot of specialists should be employed in industry. For example, transportation of men and coal is the responsibility of the mine manager and the section foreman. The chief electrician is responsible for the maintenance of equipment.

There are various methods of coal getting, but the main difference is made between opencast (open-cut) mining and underground one.

Opencast mining, although it is much cheaper than underground, may be used only when coal seams either come out to the surface or are near it. In this case hydraulic methods and excavators are widely used to get coal.

When coal is far (sometimes at a thousand feet depth) from the surface it has to be worked by underground mining. Among the underground methods there are room-and-pillar (камерно-столбовой), longwall (выемка лавами) advancing, longwall retreating, level system and some others.

In early days coal was worked by the miner lying on his back and cutting the coal with a pick. Today many mining processes are mechanized, powerful coal-cutting machines having replaced the miner. Steady increase of coal output would be impossible without the introduction of the improved and highly efficient methods as well as the extensive development of mechanization and automation.

5. COAL MINING DEVELOPMENT IN KUZBASS

Coal mining industry in Kuzbass includes over 70 mines, about 25 collieries and 17 preparation plants. Nearly 70% of the coal mined is supplied to all regions of Russia as well as to the countries of the Commonwealth of Independent States.

In the earliest days coal was mined with the «obushok» coal-picks. The 1930s are considered to be the start of mechanization. For many years a panel system had been used. It was invented by N. Chanakal to mine the

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thick and steeply inclined coal seams, mostly in the Prokopjevsk-Kiselevsk mining district, rich in coking coal.

Mining combines introduced in 1940-1950 for slightly inclined coal layers were later replaced by powerful mechanized complexes. Coal winning done by complexes makes up about 40% of the total coal output.

Many of the Kuzbass’s coal deposits allow open pit extraction. The first open-pit colliery started operating in 1948. Since then this method has got a wide-scale application. It has a lot of advantages, a major disadvantage being that of ruining the earth’s surface and small rivers. To overcome this problem open-cast mining should be combined with the land recultivation.

The end of the 1950s saw the first hydraulic mine. To break and transport the coal to the surface water has to be pumped under a high pressure. If used for steep layers, the method may have a fine future. We know of further development of so-called underground gasification method, the main idea of which is to burn the coal underground to produce gas fuel.

Thus, Kuzbass is believed to be the only coal mining area where all known technologies of coal extraction are used.

6. COAL PREPARATION

Coal preparation (обогащение) is a technological process aimed at raising the coal quality. When extracted coal is a mixture of lumps of different sizes and ranks, having various proportions of dirt, which comes from the seam and from the roof and the floor of the face (забой). Therefore, the preparation plant has to deal both with coal and rock lumps, sometimes weighing 100 pounds or more, and with fine dust.

There are different methods of coal preparation or cleaning, i.e. the separation of dirt. The simplest one, which begins in the mine, is mechanical cleaning, that is, the removal of impurities by mechanical units such as dustsuppressors, for example.

At present, when mines apply mechanized loading of coal onto conveyors, little sorting of dirt can be done underground. That’s why mechanical methods to remove the dirt, to size and to clean the coal on the surface have become an essential part of every modern colliery.

Sizing and sorting are usually performed on the screens. Screening is a process by which coal particles of different size are separated into groups with particles of the same size. It is generally done by passing the coal through a number of screens, each one having the openings of one size only. Cleaning is done either in the coal-washing or in dry-cleaning plant. The

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choice and position of the coal-preparation plant depends on the quality of the coal extracted.

The task of coal preparation is to treat it in such a way as to produce the maximum quantities of high-quality coals by the most economical means.

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1. COAL EXTRACTION AND UTILIZATION

Man realized the heating quality of coal long ago. Coal is most commonly used for producing electricity, for heating and powering industrial facilities, for making steel. Being the basis for most branches of industry, it is widely used to drive powerful vessels and locomotives as well as in metallurgical industry. Chemicals derived from coal are used in the manufacture of nylon, paints, plastics, synthetic rubber, aspirin and thousands of other useful products.

The world’s coal production is expected to grow, and its share in world’s power generation will increase from 37 up to 40 per cent in 2010. Prospected coal reserves in the world are estimated to be sufficient for the next 250 years whereas the reserves of gas and oil will be depleted in about 70 and 40-50 years, respectively.

The countries with the largest coal deposits are China, Russia and the USA, having about 45, 30 and 23 per cent of the world’s total reserves, respectively. It should be said, however, that while coal production and consumption in China and the USA tend to grow, in Russia there is a tendency to decreased production.

In Russian coal mining industry there are some first-priority problems to be solved. One of them is the introduction of advanced technologies which is a multi-purpose task. Non-traditional methods of coal getting include hydroextraction and underground gasification, production of coal slurry, deep processing of coal on site, extraction and utilization of coal seam methane, etc.

It would be impossible to apply up-to-date technologies without suitable equipment. Hence, there is another problem, that of the replacement of outdated, inefficient, environmentally dangerous equipment by advanced ones.

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2. MINING TECHNOLOGIES IN KUZBASS

We know Kuzbass to employ both underground and open-cast mining methods.

In underground mining the most wide-spread technology of mine opening is by means of vertical shafts. The level system seems to be used on a wider scale as well. According to this system the coal seam is cut into pillars as long as 800 m or more, and the coal face is advancing either down or up the raise. In mining flat and inclined, thin and medium-thick seams the longwall retreating is used.

To win coal the miners have at their disposal integrated face equipment sets, continuous miners, heading machines, drilling, loading and transportation equipment. Some mines have been completely switched over to a conveyor transportation of coal. Locomotive haulage is based on electric locomotives and large-capacity mine cars.

Open-cut mines make a wide use of hydraulic mining. They operate new excavators with a bucket capacity of 10-15 cubic meters, powerful dump trucks and drilling equipment. Hydraulic mining and hydraulic transportation are being employed on a wide scale.

It should be noted that major changes have taken place in the equipment and techniques of coal preparation. As a result of improvements in screening, washing, flotation, filtration, concentration and other processes, the output at some preparation plants has increased by more than 30 per cent. The capacity of the screens and cleaning plant depends upon the output of the mine. Inadequate capacity of the coal-preparation plant causes delays and loss of output.

A major problem of coal-mining enterprises is throwing off into the atmosphere up to 2 billion cubic metres of the methane gas. It is as much as 35% of the annual consumption of natural gas by the Kemerovo region. That’s why the nearest task is to increase the extraction and utilization of the methane from the coal deposits.

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ДЛЯ СТУДЕНТОВ ЭЛЕКТРОТЕХНИЧЕСКИХ СПЕЦИАЛЬНОСТЕЙ

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1. ELECTRIC POWER

Everyone knows electric power to be generated by converting heat, light, chemical or mechanical energy to electrical one. Most electrical energy is produced at large power stations by means of converting mechanical energy or heat. The mechanical energy of falling water is used to drive turbine generators at hydroelectric stations, and the heat derived by burning coal, oil, or other fossil fuels is used to operate steam turbines or internalcombustion engines that drive electric generators. Also, the heat from the fissioning of uranium or plutonium is used to generate steam for the turbine generator in a nuclear power plant.

Electricity generated by the conversion of light or chemical energy is used mainly for portable power sources. For example, a photoelectric cell converts light energy to electrical one for operating the exposure meter (экспонометр) in a camera, and a lead-acid battery converts chemical energy to electrical one for starting an automobile engine.

Electricity is believed to be clean, inexpensive, and easily transmitted over long distances. Since the 1880s it has had an ever-increasing role in improving the standard of living. It would be impossible to operate numerous pumps, elevators, power tools, furnaces, refrigerators, air-conditioners, radios, television sets, industrial machinery, and many other kinds of equipment without electricity. It has been estimated that in developed countries about 43 per cent of the electric power generated is used for industrial purposes, 32 per cent – in homes, and 21 per cent – in commercial enterprises.

2. VARIETIES OF ENERGY

In the world there are many different sources of energy, both potential and kinetic. One of them is water falling from a high level such as an upland lake. Another one is wind or moving air. Other sources include sea tides, heat from subterranean sources, the energy of the atom as well as coal and oil deposits.

But all these sources and stores of energy are not equally useful to mankind. Moreover some of them such as coal and oil can never be replaced by us when once exhausted. On the other hand, stores of high level water are

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continually being replaced by rain. And we believe that wind and tides will never cease to exist.

Energy sources are known to be distributed very unequally. Such countries as Norway and Switzerland, for example, are rich in water power while England, being rich in the potential energy of coal, is poor in water resources, and there are few oil wells as well.

A very important factor for man is the possibility of converting energy from one form to another. The form most required by us is mechanical rotational energy. Everyone knows this energy to be used to rotate shafts in a factory for driving various machines as well as for driving the wheels of automobiles and locomotives.

Devices converting energy from one form to another are called engines, which may be of different types. Mechanical rotational energy, for instance, may be produced either by a heat engine converting heat energy or by a turbine or water engine converting the kinetic energy of falling water.

3. CONDUCTORS AND INSULATORS

An electric current was established to be a stream of electrons moving along a conductor. Substances differ in electrical conductivity which depends on the ease with which their atoms give off electrons. Accordingly, they are divided into conductors and insulators.

We know conductors to be the materials with a low resistance so that current easily passes through them. The lower the resistance of the material, the more current can pass through it. The most common conductors are metals, the best of them being silver and copper. Copper being much cheaper than silver, it is widely used to manufacture wire conductors.

It should be taken into consideration that most materials change their resistance with changes in temperature. Electricians know that with the increase of temperature the resistance of metals is also increasing while that of carbon is decreasing. The less is the change of resistance with the change of temperature, the more perfect is the resistance material.

Materials having a very high resistance are called insulators. It is very difficult for current to pass through insulators. The most common insulators include air, paper, rubber, plastics.

Any insulator can conduct current when a high enough voltage is applied to it. But in order to make insulators conduct, currents of great value must be applied to them. The higher the resistance of an insulator, the

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greater the applied voltage has to be. The main function of insulators is to isolate conducting wires and thus to prevent a short between them.

4. TRANSMISSION LINES

Electric energy generated at the power stations is to be transmitted to the consumer. To carry electricity to far-off places it is necessary to have high-voltage power transmission lines. The length of lines varies from area to area, depending on the distance to be covered. Electric power is generally transmitted by using not a direct (d.c.) but an alternating current (a.c.) that reverses direction 25, 50, or 60 times per second.

Thick wires carrying electricity across the country are supported by very high pylons so that nobody would touch them. The best metal conductor is known to be copper, but the wires are usually not copper but aluminium, thirty wires together forming one thick cable. Aluminium being very light, the pylons can easily hold the cables.

Wire conductors offer resistance to the current flow. The longer the wire, the greater is its resistance. Accordingly, the higher the resistance, the greater are the heat losses in the wire. In order to reduce the losses a stepdown (понижающий) transformer can be used.

Electricians distinguish between a «power line» and a «power network». The difference between them is the absence (line) or the presence (network) of parallel branches. According to their functions, power lines and networks are subdivided into transmission lines and distribution ones.

Transmission lines serve to deliver power from a station to distribution centres. They are also used to connect a number of stations together, forming in this way a «power system». Distribution lines deliver power from distribution centres to the consumers.

5. ELECTRIC POWER INTERRUPTIONS

On November 9, 1965, at 5:16 p.m. a backup relay (реле резервной защиты) failed at one of the five main transmission lines at No.2 power station near Toronto, Canada. As the load had shifted to the other four lines, they became overloaded, and as a result the relays failed in all four lines. The failure resulted in the load being shifted to the other power plants in the system. The plants got overloaded, which caused them to shut down. Within minutes, power plants in Canada, New York, and the New England states got out of service. The blackout (перерыв в энергоснабжении) affected 30

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million people and covered an area of 306,000 sq. m. In some areas, such as New York City, power was not restored for about 13 hours.

This massive power blackout was followed by the establishment of the national Electric Reliability Council in June 1958. The task of the council is to set standards for the design, operation, and maintenance of generating and transmission systems. The standards serve to prevent a failure in one power system from spreading to other systems. Yet, local system failures cannot be avoided.

Nowadays in some European countries and in the US there are from 60 to 80 power interruptions a year, in which there is a loss of service for customers for more than 15 minutes. Mostly these interruptions are caused by weather conditions including ice formation, freezing snow, lighting or storm. There can also be failures of equipment such as transformers, relays, insulators and so on. Nevertheless, the reliability of electric service is considered to be extremely high.

6. NUCLEAR SAFETY CONCERNS CONTINUE

Following the nuclear reactor accident at Chernobyl in Ukraine, in April 1986, when radioactive fallout spread across much of Europe, international attention focused on the aging nuclear reactors and uneven implementation of safety standards in the countries belonging to the Commonwealth of Independent States.

The EU (European Union) is particularly concerned about safety of nuclear reactors. In the early 1990s it decided to play a major role in international efforts to help these countries in sustainable improvements in safety by replacing old reactors with alternative energy sources, improving energy efficiency, and helping to modernise the safer reactors.

EU nuclear safety experts believe many reactors designed in Soviet times to have significant safety shortcomings. The older reactors which cannot be upgraded at reasonable cost are planned to be closed and replaced with other energy sources, including new safe nuclear power ones.

The 1999 EU programme consisted of on-site assistance in Kazakhstan, Armenia, Russia and Ukraine. There was also work to deal with environmental problems caused by poor management of radioactive waste and spent nuclear fuel, as well as assistance with the closure of the infamous Chernobyl plant. The EU contributed to efforts to secure the shelter for Unit 4 destroyed in 1986, and to establish independent nuclear regulators.

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Armenia’s government is to close the Medzamor nuclear power plant which it has to keep open until a secure alternative energy source is up and running. The EU focuses on short-term improvements to design safety through on-site projects.

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1. SOLAR POWER STATIONS

The idea of high-capacity SPS (solar power stations – гелиоэлектростанция) is not new. It is based on the thermodynamic transformation of solar radiation with the use of the steam-turbine cycle. We know such stations to be built today in different countries.

An experimental SPS with a capacity of five megawatts, which is as much as was generated by the first atomic power station, was put into operation in the Crimea. It also includes a thermal system with heat accumulators and an automated system of control over the technological processes of the entire station. The capacity of future experimental SPSs is planned to be 200 - 300 megawatts, and that of commercial stations – 5,000 megawatts and more.

Another design of high-capacity installations with direct transformation of solar energy into electricity makes use of a photoeffect. We know modern energetics to be based on units generating high voltage. Russia was the first to develop and test a high-voltage (32,000 volts) photoelectric battery. The efficiency of solar batteries was increased by means of the concentration of solar radiation. This idea (first advanced in 1970) has received universal recognition and is now being studied and developed in many foreign laboratories.

However, the efficiency of the operation of a solar power station is believed to be greatly reduced because of the limited period of its work during the year and weather factors. To overcome these drawbacks the scientists are now working at different combinations of SPSs with traditional stations – thermal, atomic, hydraulic.

2. IMPROVING REACTOR SAFETY

One of the most significant projects in nuclear safety during 1999 was the construction of a test facility for the VVER 440/213 reactors, one of the most recent types used in the CIS (the Commonwealth Independent States).