Jmimng coal by water power

ЗАДАНИЯ К ДОМАШНЕЙ КОНТРОЛЬНОЙ РАБОТЕ (горная отрасль)

Завдання 1. С словосачетанием(согласно варианту) составить разные предложения на английском во кременах: Present Indefinite, Present Continuous, Present Perfect, Past Indefinite, Future Indefinite.

 

Вариант	Словосочетания	Вариант	Словосочетания
1	to work in  the office	11	to get a new job
2	to answer the telephone	12	to go abroad
3	to write the letter	13	to meet new people
4	to make acquaintance	14	to spend the holidays
5	to make a call	15	to come to the office
6	to leave for London	16	to visit the partner
7	to get some news	17	to make a decision
8	to ask the question	18	to go to the party
9	to have a business trip	19	to have a rest
10	to use the computer	20	to watch TV news

 

Завдання 2. Переведите текст на руський язик. Составьте словар из незнакомых слов и терминов. Выучите их. Составьте к тексту вопросы разных типов. (7-10)

Вариант 1

TUNNELLING, HEADING OR DRIFTING

Dryings in stone are known as rock tunnels, stone headings, drifts or cruts. They may be driven on a level course or on a slightly rising gradient, which facilitates drainage. They may be driven to the dip possibly at high gradient, to prove or win seams lying at depth. Sometimes they are driven to connect one part of a mine with another for purposes such as haulage or ventilation, etc. Today, a large number are being driven at high speed from the shaft bottoms, inset levels in shafts or from strategical points in existing roads for the development of horizon mining. They lie mostly beneath the area of coal they are intended to win and their gradients are arranged to permit locomotive haulage.

The size of a tunnel and the method of driving it depend on many factors, such as the purpose for which it is intended, the nature of the ground to be penetrated, freedom of the ground from water, ventilation requirements, nature of supports, costs, etc. The basic tools for rock drifting are very similar to those used in sinking, especially where compressed air or electric power is not available.

Many factors influence the speed at which tunnels can be driven. Thirty years ago, for a heading of 12x6 ft in ground of medium hardness, and using pneumatic drills, speeds of from 5 to 8 yd per week were usually quite satisfactory. Today, with the introduction of horizon mining, speed in drifting has become of great importance, and the more scientific methods are being applied in collieries.

Вариант 2

A COAL-MINE

In many places seams of coal come out to the surface. Coal is worked either by opencast (open-cut) mining or by a tunnel in the seam there. But where coal is far from the surface a deep shaft is sunk into, the earth. Some shafts are a thousand feet deep. As soon as a good seam of coal is reached, an engine is installed at the mouth of the shaft..Cages are driven up and down by this engine. Miners go down the shaft in these cages. When the miners come to the bottom, each miner goes down to the part of the mine where he works.

In modern mines, many mining processes are mechanized. In the mines of our country coal-cutting machines are used instead of the miner lying on his back and cutting the coal with a pick.

Great attention is paid to the further mechanization of coalmining since the Second World War. Our people have every reason to be proud of their miners. They played an important part in the process of transformation of our country from a backward land into a mighty industrial one. The Government do all their best to.make the miners' labour as easy and safe as possible.

Only seams lying hear the surface would be worked in the early days of coal mining. At first the coal was got by opencast working. Where the coal became too deep for opencast working, tunnels were driven from the outcrop to the seam. Where possible these tunnels were driven on a slight rising gradient to allow of drainage as no pumps were then available

 

Вариант 3

MODERN METHODS OF WORKING COAL-SEAMS

The main classification of methods of working coal-seams is as follows: (1) Board and pillar; (2) Longwall advancing; (3) Longwall retreating; (4) Semi-longwall; (5) Horizon mining.

Hard and fast rules1 distinguishing between these various methods cannot be laid down in some cases as so many modifications and combinations of the methods exist at various collieries working under different conditions. The general principles underlying the three chief systems may be briefly outlined as follows:

Board and pillar mining, variously called "room and pillar", "pillar and stall", "post and bank" and "stoop and room", consists of driving "boards", "stalls" or "rooms" to split up the area to be worked, so as to leave "pillars" or "stoops", which may or may not be extracted at a later date.

Under normal workings by this method, no packing is employed. Thus pillars when extracted are generally "retreated", that is the pillars farthest away from the shafts are then taken out before those nearer the shafts.

Longwall advancing working consists of long faces or "wide places" from which all the coal is removed for a given working section and the necessary roads are made through the goaf where formerly coal lay. The roof near the working face is supported by props, bars and chocks, and by packs built up of material, which falls from the roof, or may be imported.

 

Вариант 4

OPENCAST WORKINGS

The roof and the floor encountered in most mines are excellent. This may be illustrated by the fact that working places 15 ft to 40 ft in width are driven without support. Wood props are cheap and plentiful and are thus used almost universally; steel props,.bars and arches are seldom employed. Geological disturbances are not troublesome in American coalfields as in Britain. Spontaneous combustion is almost unknown, and apart from a few mines, gas emission is generally less than in the majority of seams in Great Britain.

Sometimes, but rather rarely, extensive and fairly level deposits of coal are discovered beneath a few feet of overburden, and may readily be won by opencast workings. It is probable that opencast exploitation of outcrop coal is more successful than the mining of such coal from workings.

Opencast affords greater safety, more complete extraction, maybe less subsidence, and less surface damage. Sites are now worked where the ratio of overburden to coal is greater than 15 to 1, and depths may exceed 150 ft.

Conditions vary widely, and rarely, indeed, opencast workings are similar.

After the preliminary work of prospecting, drilling, trench­ing, draining and preparation of any access road, etc., the major task of removing the overburden commences. Heavy-duty loader excavators, capable of excavating 700-800 tons per hour, are used for removing topsoil from a line of outcrop.  

Вариант 5

JMIMNG COAL BY WATER POWER

Hydraulic mining is a new system of coal getting. In this method, the coal is won from the seam by the power of high-velocity water jets directed at the seam from a power hose, called a monitor. When the coal has been broken down, the water jet is used again to clear the floor of the working place and to drive the coal along to the point of collection.

Hydraulic mining, which is extensively practised in our country and to a lesser extent in Poland and New Zealand, gives a high rate of output per man shift. The equipment is easy to operate and to move and although a considerable amount of power is required to supply high-pressure water to the monitor, this can be generated on the surface where the plant does not require expensive housing or flame-proof electrical equipment.

The British coal is of medium hardness and although it contains some bands of stone, it is not anticipated that there will be any difficulty in removing it from the seam with the pressures available.

It has been established at some British mines that water pressure of 600 lb. per sq. in. is sufficient to break down the softer coals and pressures up to 1,200 lb. for the hard and denser coals.

Only four men are needed to work each monitor, one to control the monitor and the others to attend to the pipes and flumes and fix supports. The experience in our country suggests that production can be as opencast mining, or between three and five times higher than with conventional methods

 

Вариант 6

MINE SUPPORTS

Before the removal of the coal, the upward reaction of the coal along the roof surface was equal to the downward compressive force, and under the action of the force of gravity the rocks were compressed.

As soon as a free surface, such as the roof of a roadway, is formed, the first result is the tendency for the roof beds to expand or bulge into the roadway.

It is not a function of any element of mine support to resist absolutely any movement of the strata under which it is set. This is impossible, and any support that cannot in any way yield to the inevitable movements of the strata must either be broken, bent or penetrate into the roof or floor bed between which it is set.

The function of any element of support must be considered in relation to the function of other elements of support within the area being supported. These other elements may be arti­ficial supports introduced after the extraction of the coal or any natural support provided by pillar or coal sides.

For example, on a coalface, each element in the system of supports, nogs, props, chocks and packs plays its part, and the efficiency of any one will react on the others. Chocks and props, when of the right material and properly set, are complementary to each other.

The chief kinds of materials used for mine supports are timber, steel, stone, brick and concrete.

Вариант 7

COAL PLOUGHS

The coal plough was originally introduced in Germany in 1942 since when the technique of coal ploughing has been considerably developed and improved. The framework of the original unit known as the standard plough is of fabricated steel with articulated sections to facilitate its use on uneven floors and to enable it to negotiate small faults. It comprises the cutter loaders carrying the shearing blades, the track-clearing device and the pulling bars. The machine shears and loads in both directions as it travels along the face, the above-mentioned units being duplicated at each end.

When working parallel to the cleat of the coal both shear blades are identical, but for other directions of advance it may be advantageous for the blades to be set at different angles. The blades are made of 7/8-in. steel plate with cutting edges of hard alloy electrically welded thereon. The design of the blade is important and has been the subject of much investigation in many countries, in order to ascertain the appropri­ate angles between the vertical and the cutting edge and the best wedge angle. Normally the cutting edge slopes back at an angle of 25 deg. to the vertical and the wedge angle is 38 deg. with a clearance of 7 deg. between the blade and the coal face. The blades are detachable to allow of regrinding, which becomes necessary after a cutting travel of 12,000 to 15,000 yards.

The cutter holder is plough-shaped in profile to deflect the coal on to the conveyer. The plough unit is pulled to and from along the coalface by rope haulages, installed in the gate roads at each end of the face, which are capable of exerting a pull of 10 to 12 tons with a single rope or double these values with double purchase.

 

Вариант 8

POWER LOADING

Further evidence of the technical progress in underground operations is afforded by developments in mechanical loading of both coal and stone. For many years many attempts were made to design machines suited for this work.

By the early forties of the present century power-loading machines were being introduced rapidly in some countries where pillar and stall methods are almost universal. The designing of machines suitable for use in longwall work, however, presented special difficulties. Longwall methods call for machines specially designed for the class of work in which a continuous buttock is filled from a face. The original loaders, which cut the coal as it, travelled along the face in one direction and loaded it on to a belt as it travelled in the opposite direction, represented a landmark in the development of mechanical mining. Later these machines were modified to cut and load the coal in a single operation and such ma­chines came into operation after the Second World War.

Many types of machines have from time to time been tried for this purpose and their use is gradually increasing, but much remains to be done in this connection.

In the reorganization of existing collieries and in the planning of the development of new sinkings, locomotive haulage is to be adopted wherever conditions permit. The advantages of this system is that reduced personnel engaged in haulage operations, particularly where there are a number of junctions and loading stations to be served from one road.

 

Вариант 9

CONVEYERS

A system of conveyers is commonly divided into two sections: (a) transport on the face; (b) transport by gate or room and trunk conveyers.

There are three main types of face conveyers:

(1) jigging or shaker conveyers;

(2) belt conveyers;

(3) scraper conveyers.

Each of these suits best certain conditions of inclination, output or custom in the coal-field.

The shaker conveyer is essentially a downhill conveyer and although it may function satisfactorily in level conditions it is rarely suitable for even a slightly rising gradient.1

This conveyer consists of a line of troughing in 10 or 11 ft sections connected to each other by bolts and nuts, ropes, or by wedges and other quickly-connected fasteners. The pans (troughing) are mounted on rollers and cradles shaped to give an abrupt stop at the end of the forward stroke of the conveyer, or on steel balls confined in frames which give only a horizontal motion to the troughing.

For a high concentrated output whether the coal is delivered uphill or downhill,2 the belt conveyer, consisting of a driven drum, a double length of belting and a tension drum, is generally preferred for face work. The width of the belting employed varies from 20 in. to 26 in. and exceptionally 30 in., and the speed is from 100 to 200 ft per minute. 

 

Вариант 10

THE WINDING OF COAL

Two methods are used for transporting coal through mine shafts: by cages, carrying the coal in tubs or mine cars; and by skips, into which the coal is loaded direct.

Cage winding, with coal loaded into pit tubs, has been the standard practice for many years. In the early days, when coal was worked entirely by hand, the pit tubs were taken to the face to be filled direct. Consequently, pit tubs were small, holding only 4 to 6 cwt, or even less; they were usually constructed of wood and were manhandled on the coal face and in the gate roads. The development of longwall working, the introduction of coal-cutting machines and, later, the extended use of face and gate conveyers led to an increase in the size of tubs, which were loaded in the gate road or main road and hauled outbye to the pit bottom. Modern pit tubs, constructed in fabricated steel, have capacities up to 35 cwt and their introduction was an important factor in the development of winding technique.

At the present time the limiting pay load is 10 to 12 tons from 1,000 yd, with a maximum winding speed of about 60 ft

Up to the beginning of the present century the coal was filled into tubs at the working face. If the thickness of the seam permitted, the tubs were taken along the face and filled at the site of coal getting. But in thin seams it was thrown back along the working face and filled into tubs at the gate end.

 

Вариант 11

SKIP WINDING

The winding of coal in skips has received much attention in recent years. In this system of winding coal is discharged from the tub or mine car at the shaft bottom by tipping it into hoppers, from which it is loaded into the skip in bulk and sent (wound) to the surface.

The advantages of skip winding have been appreciated for many years from experience gained in ore-mining. A skip installation comprises three sections. These are the skip, the loading plant and the discharge plant. Skips may be divided into two types, viz, the overturning skip and the bottom-discharge skip.

The overturning skip is similar in action to the overturning cage and suffers many disadvantages. It is widely employed in ore-mining, but is rarely used in coal-mining.

The bottom-discharge skip was introduced into certain European coal-mines some twenty years ago.

The skip is usually constructed mostly in steel, but light-alloy sheets are sometimes used for part of the structure to improve the ratio of pay load to gross load.

For raising large outputs from great depths, the size of the rope becomes so large as to give rise to difficulties in manufacture and handling. Difficulties arise when the diameter of the rope required exceeds about 2.25 in.

During recent years the problem of rope size has been solved by the introduction of multi-rope friction winding, in which two or more smaller ropes are substituted for a single rope previously employed.

 

Вариант 12