Geology. Козлова Е.П. - 33 стр.

                          Exploration of Mineral Deposits

       Exploration is known to include to whole complex of investigation 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 economical 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. 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 exploration 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.
       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.
       In prospecting for a seam one of the tasks of the preliminary survey is to
establish the full geological sequence of rocks in the deposit. A prospecting pit
therefore sunk to establish the thickness of the overburden and the angles of dip and
strike. When the thickness of overburden seems to be small (up to 3 – 4 m) and the
angles of dip is steep, trenches are used for exploration. In very gently sloping seams
boreholes are used for exploration because neither trenches no pits can give results.
       There are special features in the search for veins which are less regular in shape
and smaller in area along both the dip and the strike. Prospecting for veins under
shallow overburden is said to be performed by trenching; under deep overburden it is
by pits and crosscuts.
       The quality section of the mineral deposit is determined on the basis of
analyses and test of samples taken from exploratory workings.
       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.
       Exploitation exploration is known to begin as soon as mining operation start. It
provides data for detailed estimates of the ore reserves of individual sections. It
facilitated the planning of current production and calculating the balance of reserves
and ore mined.
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