Exercises:

1. Answer the following questions:

1.How is coal mining in the USA organized?

2.What can you say about office workers?

3.Who is a mine manager?

4.What does he coordinate?

5.Who is a section foreman?

6.What are his functions?

7.What are two areas of transportation?

2. Translate into Ukrainian paying attention to the attributive groups:

1. The coal mining industry is one of the leading branches of our national economy.

2. Underground hydraulic mining is used at some mines.

3. The conventional longwall method is applicable to seams of all inclinations.

4. Longwall advancing and longwall retreating workings are the two main mining methods employed at our coal mines.

5. Room-and-pillar working is greatly favoured in the USA.

3. Retell the text.

14. Fossil fuels

The chief sources of energy available to man today are oil, natural gas, coal, water power and atomic energy. Coal, gas and oil represent energy that has been concentrated by the decay of organic materials (plants and animals) accumulated in the geologic past. These fuels are often referred to as fossil fuels.

The word 'fossil' (derived from the Latin fodere 'to dig up') originally referred to anything that was dug from the ground, particularly a mineral. Today the term 'fossil' generally means any direct evidence of past life, for example, the footprints of ancient animals. Fossils are usually found in sedimentary rocks, although sometimes they may be found in igneous and metamorphic rocks as well. They are most abundant in mudstone, shale and limestone, but are also found in sandstone, dolomite and conglomerate.

Most fuels are carbon-containing materials that are burned in air. In burning fuels give off heat which is used for different purposes.

Fuels may be solid, liquid and gaseous. Solid fuels may be divided into two main groups, natural and manufactured. The former category includes coal, wood, peat and other plant products. The latter category includes coke and charcoal obtained by heating coal in the absence of air.

Liquid fuels are derived almost from petroleum. In general, natural petroleum, or crude oil, as it is widely known, is the basis of practically all industrial fuels. Petroleum is a mixture of hundreds of different hydrocarbons — compounds composed of hydrogen and carbon — together with the small amount of other elements such as sulphur, oxygen and nitrogen. Petroleum is usually associated with water and natural gas. It is found in porous sedimentary rock where the geological formation allowed the oil to collect from a wide area. Petroleum is one of the most efficient fuels and raw materials.

Of gaseous fuels the most important are those derived from natural gas, chiefly methane or petroleum. Using gaseous fuels makes it possible to obtain high thermal efficiency, ease of distribution and control. Gas is the most economical and convenient type of fuels. Today, gas is widely utilized in the home and as raw material for producing synthetics. Generally, all types of fossil fuels described in the text are of great economic importance as they represent the sources of energy the man uses today.

Notes

wood – деревина

petroleum – пальне

fossil – копалина

includes – містити у собі

efficiency – продуктивність

charcoal – деревне вугілля

Exercises:

1. Answer the following questions:

1. What fuels are often referred to as fossil fuels?

2. What does the word 'fossil' mean?

3. In what rocks are fossil fuels most abundant?

4. What types of fossil fuels do you know?

5. Is coke natural or manufactured solid fuel? And what can you say about coal and peat?

6. How are coke and charcoal produced?

7. What rocks is petroleum usually associated with? Why are gaseous fuels important?

2. Read the following sentences. Find out those which correspond to the text.

1. Coal, water power and atomic energy are the only sources of energy available to man today.

2. Coal, wood and peat represent natural group of solid fuels.

3. As a rule fossil fuels are found in sedimentary rocks.

4. Crude oil is widely used for producing solid fuels.

5. Petroleum can be found in porous sedimentary rock. In producing synthetic materials gas is used.

6. Not all types of fossil fuels burn.

15. COAL

Large quantities of coal have been formed in nature by the slow decomposition of vegetable matter without much heating but in the presence of water and away from air. Coal consists of free carbon admixed with various carbon compounds and mineral matter. There are four general kinds of coal: anthracite (hard coal), bituminous coal, lignite, and brown coal.

Hard coal contains about 6 per cent of volatile matter. It ignites with some difficulty but gives a great deal of heat in burning without producing much smoke or flame. Hence it is suitable for domestic heating and for firing boilers or ships.

Soft coals contain much volatile matter, but the amount varies. They burn with a bright smoky flame and are used for ordinal fuel. They are of two general kinds, coking and non-coking coals. Coals rich in volatile matter are selected for producing coal gas.

Coal, like practically all other material substances which man has learnt to extract from the crust of the earth, requires, as a rule, some form of preparation to fit it for utilization in the best possible manner in various industries. The process of cleaning coal, or the separation of dirt from it, begins in the mine.

In the recent years the rapid increase in mechanical cutting and loading has hastened mechanical cleaning. By mechanical cleaning is meant the removal of impurities by mechanical units as compared with hand picking by which the impurities are removed by hand. It is impossible for a mine to turn over to mechanized loading without the addition of some mechanical cleaning facilities, at least on certain sizes. The problem of coal preparation is to take the coal from the mine and to treat it so as to produce the maximum quantities of the most easily marketable grades in the most economical manner possible.

The principal methods employed for cleaning coal are classified as follows: 1. Hand cleaning. 2. Dense medium washing. 3. Jig washing. 4. Trough washing. 5. Classifiers. 6. Dry cleaning. 7.Froth flotation. 8. Concentrating tables. 9. Convertor process.

Notes:

matter – речовина

volatile – летючий

dirt – бруд

impurity – доміш

Exercises:

1. Answer the following questions:

1. How have large quantities of coal been formed?

2. What does coal consist of?

3. How many general kinds of coal are there?

4. What are they?

5. Where does the process of cleaning coal begin?

6. What is meant by mechanical cleaning?

7. What has hastened mechanical cleaning?

8. What are the principal methods employed for cleaning coal?

2. Translate into Ukrainian paying attention to the gerundial constructions:

1. We have learned of coal being composed of carbon, hydrogen and oxygen in complex groupings.

2. We know of minerals being cleaned before usage.

3. We knew of minerals being divided into rock-forming minerals and ores.

4. Many reporters mentioned new washing plants having been constructed in that district.

5. We know of three-product separation being the best method.

3. Retell the text.

16. THE PREPARATION OF COAL FOR USE

Coal sent from the mine comprises a mixture of different sizes and grades admixed with varying proportions of dirt or refuse, some of which comes from the seam itself and some from the roof and floor. Under modern conditions, when coal is loaded by shovel or by a power-operated loading machine on to a conveyor, little sorting of dirt is done underground. So mechanical methods to remove the dirt, to size, to sort and clean the coal on the surface have become an essential part of the surface plant of every modern colliery. The preparation plant must therefore handle lumps of rock sometimes weighing 100 lb. or more, and to deal also with fine dust.

Sizing and sorting are usually performed on the screens. Cleaning is done in the washery or dry-cleaning plant. It is necessary to note that the choice and position of the coal-preparation plant must be considered in planning the colliery. The coal-preparation plant must be placed at a distance of not less than 80 yards from the shaft.

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. Modern coal-preparation plants have nominal capacity of 1,500 tons per hour. All the principal methods of coal cleaning are used at the modern coal-preparation plants.

Notes

mixture – суміш;

colliery – вугільна копальня;

screen – сортувальний пристрій, решето.

Exercises:

1. Answer the following questions:

1. What does raw coal comprise?

2. What does dirt come from?

3. What units are sizing and sorting performed on?

4. Where must the coal-preparation plant be placed?

5. What nominal capacity has a modern coal-preparation plant?

2. Translate into Ukrainian paying attention to clauses:

1. We know that minerals are cleaned before usage.

2. We knew that minerals were divided into rock-forming minerals and ores.

3. We know that many methods are employed for mineral cleaning.

4. They were informed that new reagents were used in froth flotation.

5. We knew that mechanical means of cleaning were widely used in mineral dressing.

3. Retell the text;

4. Translate the following text into Ukrainian in written form:

17. SCREENING

Screening is a process of separating mixed particles into groups of particles of the same size. In coal preparation, sizing is generally accomplished by passing the coal over screens. Separation with screens is a very old industrial practice, but it became general only in the second half of the 19^th century. Preparation outside the mine started with the installation of stationary cast-iron plates with 4 to 6 in. square holes. The run-of-mine coal was dumped upon the platforms, the large pieces of rock were picked out by hand and the large lumps of coal were broken with hammers.

The simple products of screen sizing are an «under-size» and «over-size». «Under-size» consists of particles of coal which fall through the holes of a particular screen. «Over-size» consists of pieces or particles which could not fall through the openings. The fundamental elements in screening are the passage of under-size particles through the screen openings and rejection of over-size particles.

Notes:

particle – частка

installation – встановлення

hole – отвір

rejection – відхілення, відмова