Text b. Exploration of Mineral Deposits

Exploration is known to include a whole complex of investiga­tions carried out for determining the industrial importance of a deposit. The main task is to determine the quality and quantity of

mineral and the natural and economic conditions in which it oc­curs. The exploration of the deposit is divided into three stages, namely preliminary exploration, detailed exploration and exploita­tion exploration.

The aim of preliminary exploration is to establish the general size of a deposit and to obtain an approximate idea of its shape, dimensions and quality. At this stage the geological map of the de­posit is corrected and a detailed survey of its surface is completed. The information on the preliminary exploration is expected to give an all-round description of the deposit which will enable the cost of its detailed exploration to be estimated.

The following points should be taken into consideration: 1) the shape and area of the deposit; 2) its depth and angles of dip and strike; 3) its thickness; 4) the properties of the surrounding rock and overburden; 5) the degree of uniformity of distribution of the mineral within the deposit and the country rock, etc.

Preliminary explorations can make use of exploratory openings such as trenches, prospecting pits, adits, crosscuts and boreholes. They are planned according to a definite system, and some are driven to a great depth.

All the exploratory workings are plotted on the plan. These data allow the geologist to establish the vertical section of the deposit.

The quality of the mineral deposit is determined on the basis of analyses and tests of samples taken from exploratory workings.

The method of exploration to be chosen in any particular case depends on the thickness of overburden, the angle of dip, the sur­face relief, the ground water conditions and the shape of the min­eral deposit.

The task of the detailed exploration is to obtain reliable informa­tion on the mineral reserves, their grades and distribution in the different sectors of the deposit. Detailed exploration data provide a much more exact estimate of the mineral reserves.

Mine or exploitation exploration is known to begin as soon as mining operations start. It provides data for detailed estimates of the ore reserves of individual sections. It facilitates the planning of current production and calculating the balance of reserves and ore mined.

The searching and discovering of new mineralized areas are based on geological survey and regional geophysical prospecting. The results of these investigations provide data on iron-bearing formations and new deposits for commercial extraction.

In detailed exploration both underground workings and bore­hole survey are used. Core drilling with diamond and carbide bits is widely used. Non-core drilling is also used in loose rocks in combi­nation with borehole geophysical survey.

One of the main methods to explore coal deposits is also core-drilling. Modern drilling equipment makes it possible to accurately measure bed thickness and determine structure of beds, faults and folds. Recording control instruments are attached to drilling rigs which allow the geologists to get reliable samples good for nearly all parameters of coal quality to be determined.

Ex. 16. Find in the text sentences proving these facts.

1. The purpose of preliminary exploration is to determine the mineral reserves and their distribution in the different sectors of the deposit.

2. The properties of the surrounding rock and overburden should be taken into consideration during the preliminary explora­tion.

3. The purpose of the detailed exploration is to find out the quantity (reserves) of the deposit.

4. Exploitation exploration facilitates the planning of current production.

1. Both core drilling and non-core drilling are widely used.

5. Recording control instruments allow geologists to get reliable ore samples.

Ex. 17. Answer the questions.

1. What stages does exploration include?

2. What is the main purpose of preliminary exploration?

3. What should be taken into consideration by geologists during preliminary exploration?

4. What exploratory openings do you know?

5. Do you know how the quality of the mineral deposit is deter­mined?

6. What is the aim of a detailed exploration?

7. Is core drilling used in prospecting for loose rocks? 8.What is drilling equipment used for?

Ex. 18. Find in the right column Russian equivalents of these words.

bedded deposits core drilling S.the angle of dip of the seam the thickness of overburden exploratory workings composition of minerals pits and crosscuts to exploit new oil deposits sampling 10. geological section

а) мощность наносов b) разрабатывать новые месторождения нефти c) шурфы и квершлаги d) пластовые месторождения e) опробование (отбор) образцов f) угол падения пласта g) колонковое бурение h) геологический разрез (пород) i) состав минералов j) разведочные выработки

Ex. 19. Find in the right column English equivalents of these words.

буровые скважины по простиранию пласта равномерность распределе­ния минерала в залежи водоносность пород карбидные и алмазные коронки детальная разведка использовать новые поисковые методы проникать в залежь коренная порода 10. свойства окружающих пород

а) ground water conditions b) detailed exploration c) boreholes d) along the strike of the bed (seam) e) carbide and diamond bits f) the uniformity of mineral distribution in the deposit g) the properties of surrounding rocks h) to make use of new prospecting methods i) country rock j) to penetrate into the deposit

Ex. 20. Match a verb with a noun.

1. to discover a) oil and gas

2. to drive b) valuable minerals

3. to extract c) a proper method

4. to estimate d) new coal-fields

5. to choose e) crosscut (adit, drift)

6. to determine f) the cost of the project

7. to sink g) holes

8. to search (for) h) lead and copper

9. to take i) reserves

10. to smelt j) samples

11. to drill k) iron ore

l) pits

Ex. 21. Retell text B using this plan:

1. The task of the preliminary exploration.

2. Exploratory workings used at the preliminary stage of exploration.

1. Sampling as a means of determining the quality of the min­ eral deposit.

3. The aims of the detailed proving and exploitation exploration.

Ex. 22. Read text C and name the main methods of prospecting.

Text C

1. World-wide economic development has been characterized by the growth rates in the demand of raw materials and especially for the primary sources of energy. Despite the development of nuclear energy, the expansion of off-shore oil and natural gas production, the extraction of oil from bituminous sands and oil shales, the liquefaction (разжижение) and gasification of coal, and the application of such sources as geothermal and solar energy, the burden (бремя) of energy supply will 'continue to fall on the producers of fossil fuels for many years to come. This applies particularly to the production of solid fuels.

2. As is known, most minerals are mined from surface deposits now. Even though the mining industry continues the search for low-grade surface deposits, it is increasingly necessary that the economic subsurface deposits should be mined. This fact leads to the development of new methods of prospecting.

3. New techniques have been developed for rapid mapping and geochemical sampling from light aircraft while in flight. Statistical studies of regional geochemical sampling aided (помогать) by computers are being widely adopted. In general, computers play an important role in the quick interpretation of geological problems. Colour photography is also being used as an aid in certain geological work and mining studies.

4. A method of prospecting for mineral, gas, oil, etc. which is based on a combination of X-rays and ultrasonic transmissions came into use recently. The method is fully portable and of great value in drilling. In addition, this method determines the areas of interest during drilling and gives close grade control during mining operations.

5. At present, the scientists are conducting intensive research aimed at using geocosmic rays as a means of determining the size of an ore deposit in the prospecting stage. As is known, until recently scientists dealt only with the interplanetary functions of cosmic rays. Cosmic rays coming in from the depths of the Universe are expected to explore near-earth and interplanetary space.

6. The geocosmic method is based on the fact that when the cosmic rays get into the atmosphere, the so-called secondary cosmic rays, muons, appear. These particles are capable of penetrating rather deep into the Earth's crust. The greatest muon penetration depth registered today is stated to be about three thousand metres. This fact has suggested the idea of using the rays in mineral prospecting.

7. Besides, successful development of space research has made it possible to survey the Earth's resources from space by satellites. The advantages of the surveys of the Earth's resources by satellites are such that vast areas such as entire mountain belts and continents can be mapped synoptically. The greatest potential of surveying the Earth's resources from space for mineral exploration is based on the ability to map synoptically the geomorphology and general geological environment (окружающая среда) of very large areas. The results obtained provide more accurate and complete information than is available from conventional (обычный) surveys.

Ex. 23. Find in each passage of the text a sentence expressing its main idea.

Ex. 24. Give each passage a title.

Ex. 25. Answer these questions.

1. What type of fuel will continue to be the primary source of energy?

2. What deposits should be mined in the future?

3. What is the method of prospecting based on X-rays and ul­trasonic transmissions used for?

4. What fact has suggested the idea of using the cosmic rays in mineral prospecting?

5. What is the surveying of the Earth's resources from space based on?

Ex. 26. Find in the text equivalents of these words:

растущие темпы, сырье, снабжение энергией, особенно (1); низкосортный, необходимо (2); новые методы (приемы), быст­рая съемка (картирование) (3); портативный, кроме того, тща­тельный контроль за качеством (4); до недавнего времени, из глубин вселенной (5); так называемый, способный проникать (6); способность наносить на карту (картировать) (7)

Ex. 27. Which title best suit the text?

1. Methods of Mineral Prospecting.

2. New Techniques Applied in Mineral Prospecting.

3. Recent Developments in Mineral Prospecting.