ответьте на следующие во письменно, используя предложения из текста:

1. What is mining?

2. What has contributed to the better working conditions of the miners?

3. What factors influence the choice of the mining method?

4. In what case is useful mineral worked by open pits?

5. Are exploratory workings driven with a view to finding and proving mineral or are they driven for immediate extration of mineral?

6. What is the difference between development and production work?

7. What main factors are used for classifying mine workings?

8. What do the dimentions of production faces depend on?

Текст

As has been said, mining refers to actual ore extraction. Broadly speaking, mining is the industrial process of removing a mineral-bearing substance from the place of its natural occurrence in the Earth's crust. The term "mining" includes the recovery of oil and gas from wells; metal, non-metallic minerals, coal, peat, oil shale and other hydrocarbons from the earth. In other words, the work done to extract mineral, or to prepare for its extraction is called mining.

The tendency in mining lias been towards the increased use of mining machinery so that modern mines are characterized by tremendous capacities. This has contributed to: 1) improving working conditions and raising labour productivity; 2) the exploitation of lower-grade metal-bearing substances and 3) the building of mines of great dimensions.

Mining can be done either as a surface operation (quarries, opencasts or open pits) or by an underground method. The mode of occurrence of the sought-for metallic substance governs to a large degree the type of mining that is practised. The problem of depth also affects the mining method. If the rock containing the metallic substance is at a shallow site and is massive, it may be economically excavated by a pit or quarry-like opening on the surface. If the metal-bearing mass is tabular, as a bed or vein, and goes to a great distance beneath the surface, then it will be worked by some method of underground mining.

Working or exploiting the deposit means the extraction of mineral. With this point in view a number of underground workings is driven in . barren (waste) rock and in mineral. Mine workings vary in shape, dimensions, location and function.