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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


Unit 7_____________________________________________ 177

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.


178_____________________________________________ Unit 7

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.

25. , .
.

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 explora
tion.

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.

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

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

26. :

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 deter
mined?

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?


Unit 7



27. ) :


1. bedded deposits

2. core drilling

S.the angle of dip of the seam

4. the thickness of overburden

5. exploratory workings

6. composition of minerals

7. pits and crosscuts

8. to exploit new oil deposits

9. sampling

10. geological section


)

) -

)

)

) ()

)

)

) ()
)

)


) :


1.

2.

3.

4.

5.

6.

7.

8.

9.

10.


) ground water conditions

) detailed exploration

) boreholes

) along the strike of the bed (seam)

) carbide and diamond bits

) the uniformity of mineral distri-

bution in the deposit

) the properties of surrounding rocks

) to make use of new prospecting
methods

) country rock

) to penetrate into the deposit


28. , :


bed

Bedded

Bedding

) 1. Exploration of gently dipping ...deposits is performed by vertical pits.

2. The principal indicator of the economic importance of
combustible shales is the persistence () of the ...s in
thickness and grade.

3. As is known, any change in the normal... of a seam is called
a disturbance.

Work workable working

6)1.The term "prospecting" covers the whole range of geological ... aimed at discovering ... deposits.

2. Naturally, the prospector also finds non-... mineral con
centrations more often than economic ones.

3. Many countries have their own classification system of ...
deposits.


180_____________________________________________ Unit 7

4. The type of exploratory ...s needed depends on the thick
ness of overburden and the angle of dip.

5. The thickness of the seam considerably influences the
choice of the method of....

29. :

to look at the geological map to look for a mineral deposit

to work out a new plan to work on a difficult problem

(programme) to be made up of partings

to find out all about the to crop out at the surface

mode of occurrence of a to search for ores

mineral to touch upon the methods of

to cany out research prospecting

30. .
:

. .

1. to discover a) oil and gas

2. to drive 6) valuable minerals

3. to extract ) a proper method

4. to estimate r) new coal-fields

5. to choose ) crosscut (adit, drift)

6. to determine e) the cost of the project

7. to sink ) holes

8. to search (for) 3) lead and copper

9. to take ) reserves

 

10. to smelt ) samples

11. to drill ) iron ore

) pits

31. , It 1)
, 2) :

1. Coal is used as a fuel. Itis also important as the source of
coke for the steel industry.

2. It is possible to explore very gently sloping seams by bore
holes.

3. It is due to Karpinsky's work that we know the origin of the
coal in the Donets Basin.

4. It should be noted that there exist surface (ground) and aerial
prospecting methods.

5. Oil occurred at great depths and itwas difficult to search for
it.

32. , either
...
of, neither ... nor.


Unit 7



 

either , either ... or ... ,
    ...
neither , , neither ... nor ...
  ( )    

1. Depending on the geological conditions either adits or bore
holes can be driven into the deposit.

2. When working steep seams under thick overburden neither
trenches nor adits can be used.

3. Neither the thickness of overburden nor the angles of dip
and strike were determined correctly.

4. At present either surface or aerial methods of geological pros
pecting can be used.

5. Neither faults nor fissures were found by the surveyors.

33. ,
:

1. Oil is known to be one of the most important sources of energy.

2. Petroleum is believed to have been formed from decaying
vegetable and animal remains.

3. Drilling is considered to be the principal exploration method
and it is widely used when deposits are of large dimensions.

4. Until recently a depth of 50-ft overburden was considered to
be the maximum.

 

5. Coal is still the most important fuel and is likely to remain
the main source of energy for years to come.

6. Neighbouring coal beds seemed to be sloping gently.

7. The computerized systems of planning and control proved to
be reliable.

 

34. ,
, .
.

35.
. :

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