5. Retell the text «Screening».

18. The use of the relative dating to find resources

Many societies depended upon resources such as coal, gas, and oil to keep functioning. Knowledge of relative age and index fossils can help to locate new reserves of resources.

As you may already know, deposits of coal were formed over millions of years from dead plant matter under pressure. Much of this plant matter consisted of huge ferns and other plants growing in swamps. The rock layer that records this in Earth’s history contains rich coal reserved.

One possible way to locate coal reserves is to look at the rocks above and below known coal reserves. If one of the layers contained an index for rocks found near coal beds, you could tell if the coal might be under your feet or if it has already been eroded away. If found the index fossil for the rocks bellow the coal reserved at the surface of Earth, then you know that the coal has already been mined or eroded away. However, if you find the index fossil for the rocks that occur above the coal reserves, you know that it is possible that there is coal underneath. You can then drill a deep core of rock and study its layers. The core sample reveals whether the layer in which coal formed is present in a given area. Because it is very expensive to drill a core, it's important that you have a good reason to do so. Index fossils and relative dating can help a company locate reserves less expensive.

Exercises:

1. Answer the questions:

1.How were deposits of coal formed?

2.What is the way to locate coal reserves?

3.What can help a company to locate reserves less expensive?

2. Translate into English:

1. Для нормального функціонування суспільству потрібні природні ресурси.

2. Ви можете бурити глибоку свердловину та вивчати шар порід.

3. Поклади вугілля утворювалися на протязі мільйонів років із мертвого рослинного матеріалу під дією тиску.

3. Retell the text.

19.General information on mining ore deposits

1.In choosing the methods of working ore deposits, one must take into consideration the following main factors: 1) the shape of the deposit; 2) the dimensions of the deposit in thickness, along the strike and down the dip; 3) the geological conditions 4) the type of ore and the distribution of metal in the ore body.

2. The shape of the ore deposit affects greater the mining method than that of a bedded deposit because ore deposits change more abruptly (різко). Besides, the contact of the deposit with the country rock is of great importance.

3.According to their angle of dip the deposits are divided into gently sloping (up to 25 C), inclined (25-45 C) and steep deposits (45—90C).

4.The thickness of ore deposits also varies. They may be very thin(0.7 to 0.8m), thin (0.8 to 2 m), medium-thick (2 tо 5 m), thick (5 to 20m) and extremely thick(more than 20 m).

5. A rational method of mining either an ore or a bedded deposit ensures the following: 1) safety; 2) minimum cost of production, 3) minimum losses of ore; a) a rate of extraction.

Access to underground mines is by shaft, slope or drift openings. Many metal mines employ a combination of these and all mines have a minimum of two access opening to facilitate circulation of air through the mine and to provide additional means of escape(зд. вихід) in case of emergency (крайня необхідність, непередбачений випадок).

6. In metal mining as well as in mining bedded deposit opencast and underground methods of mining are used but opencast mining predominates now. The main trend has been toward low-coast opencast mining. Much attention is paid to large near-suriace deposits which offer the possibility of achieving economies because the cost per ton of ore mined by underground methods is generally far higher than that for opencast mining. Thus, in our country more than four-fifths of all the iron ore is now obtained by this method. The largest enterprises are in the Kursk Magnetic Anomaly, in the Krivoy Rog Basin, in the Urals and in Kazakhstan. Giant enterprises capable of producing tens of millions of ore every year have been built and others are under construction. The capacity of the mining enterprises especially newly built has also greatly increased. For example, the annual iron ore output of a number of quarries of the Krivoy Rog Basin has exceeded millions of tons per each mining enterprise.

7. Large volumes of mineral output determine the necessity in constant improvement of technical and economic indexes of mining industry's activities One of the main problems which face the mining industry is the optimum planning of the distribution and development of productive forces which are based on the use of economic and mathematical modeling on programming and computer methods. At present one can hardly find a mining enterprise where the operations research models and computers are not applied.

8.A great deal of attention is given now to the improving of labour conditions and ensuring the safety of miners. Our scientists and engineers are working out highly mechanized and automated mining enterprises. The only personnel employed at such enterprises will be operators, dispatchers and specialists to control the machinery and equipment.