Comprehension check

I. Decide whether the following statements are true or false according to the text:

1. Tunnels are divided into four groups depending on the ground through which they pass.

2. All kinds of tunnels require the same methods of excavation and ground support.

3. Thorough geologic analysis is one of the main tunneling operations.

4. Excavation of the ground is either cyclic or continuous.

5. Each cycle involves drilling, loading explosive, blasting, ventilating fumes and excavation of the blasted rock.

6. The dominant factor in all phases of the tunneling system is ground support.

7. In soft ground stand-up time can vary from minutes up to hours.

8. In rock stand-up time may vary from seconds up to days.

9. Ventilation provides fresh air and removes explosive gases.

10. Electronic equipment is widely used in tunnels.

II. Answer the questions

1. How are tunnels generally grouped?

2. What do tunneling operations involve?

3. Why is thorough geologic analysis very important?

4. What does each cycle involve?

5. How long will soft ground safely stand by itself at the heading?

6. Stand-up time in rock varies from minutes up to days, doesn’t it?

7. Where is control of environment essential?

8. How does ventilation work?

9. What tunnels involve a major ventilating plant?

10. Why is electronic equipment prohibited in tunnels?

LANGUAGE FOCUS

III. Fill in the prepositions.

1. To be grouped … 2. Depend … 3. Consist … 4. … order to 5. … addition to.

6. Excavation … smth. 7. Vary … up to 8. To be used …

IV. Fill in the words.

Dominant, soft, timber, sides, safe, ore extraction, meet, deep, inflow, corrosion.

1. Many mining tunnels have been planned only for minimum-cost temporary use during ….

2. In all tunnels, geologic conditions play the … role.

3. Since shallow tunnels are more often in … ground, borings become more practical.

4. Long tunnels from opposite sides of the mountain commonly … with an error of one foot or less.

5. Under most conditions, tunneling causes a transfer of the ground load by arching to … of the opening.

6. In early tunnels, … was used for the initial or temporary support.

7. For protection against … it is nearly encased in concrete as final lining.

8. Environment control is essential to provide … working conditions.

9. While excess heat is more common in … tunnels, it occasionally occurs in fairly shallow tunnels.

10. In 1970 a complete refrigeration plant was required to progress through a huge … of hot water.

V. Give the missing forms of the words below.

Verb Noun Adjective

Differ

Operator

Additional

Protect

Acceptability

Locative

Alter

Variability

Selective