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Tunneling Shaft sinking and drifting.doc
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2.10 Read and choose the proper title to the text given below.

1. Circular Shafts

2. Rectangular Shafts

3. Elliptical Shafts

4. Shape of Shafts

Shafts are necessary in mining enterprises where the mineral to be excavated is at some distance below the surface of the earth. Through them men and minerals are wound in cages or skips to the surface and the materials taken underground. They house water pipes, power supply pipes and cables. Shafts are also the medium through which the ventilating current enters and leaves the mine.

The shape of shafts. The most common shapes of shafts are: circular, rectangular and elliptical.

Circular shafts are most commonly used in coal mining. A circular shaft is desirable, especially at depth, as is best able to resist heavy side pressures. It is best suited to sinking under difficult conditions, being comparatively cheap in maintenance. It can be sunk quicker than a rectangular shaft of the same cross-sectional area, and requires less holes to be drilled per round. On the other hand, it is not so conveniently divided into compartments as a rectangular shaft.

Rectangular shafts are used extensively in metalliferous mining practice and were formerly used at coal mines. Timber lining is used in them and they can be divided into compartments with great economy in space. In practice the number of compartments varies up to a maximum of eight.

Elliptical shafts combine the advantages of both rectangular and circular shafts, namely, to obtain a strong, durable and economical section and, at the same time, to make maximum use of the available space. An elliptical shaft can have a concrete lining. The size of the shaft depends on the desired output from the mine and the type of winding.

2.11 Complete the sentences with some suitable parts.

1. Circular shafts are mostly used in … .

a) coal mining, b) metalliferous mining, c) both coal and metalliferous mining.

2. An elliptical shaft can have a … .

a) concrete lining b) timber lining c) brick and masonry lining

3. The number of compartments varies up to a maximum of … .

a) eight b) ten c) two

2.12 Match the terms and their definitions.

1. Shaft

2. Drift

3. Development

4. Exploitation

1. A vertical or inclined excavation in a mine extending downward from the surface as a principal opening through which the mine is exploited. It is provided with a hoisting engine at the top for handling men, rock and supplies.

2. The work of driving openings to and in a proved ore body to prepare it for mining and transporting the ore.

3. A horizontal opening in or near an ore body and parallel to the course or the vein or long dimension of the ore body.

4. The work of mining and marketing the ore.

2.13 Read and memorize the words.

coat

v

покрывать (краской); syn. paint

crush

v

дробить, обрушать(ся)

decay

v

распад, разложение, гниль

dry

a

cухой; ant. saturated, wet

gun

a

инжектор, распылитель

timber

n

древесина

treat

v

обрабатывать

steam

n, v

пар

обрабатывать паром

fire

n

пожар

insect

n

насекомое

waste

n

отходы, пустая порода

impregnate

v

насыщать, пропитывать

inhibit

v

препятствовать, сдерживать

poison

n, v

яд

отравить

preserve

v

сохранять

cell

n

ячейка, клетка

season

n

сезон, время года

expose

v

выходить на поверхность, обнажаться, оставлять незащищенным от воздействия

2.14. Recognize these international words.

form, temperature, optimum conditions; creosote, effective, prevertive, chemicals, cement, method, preservative, pressure process; zink chloride

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