Деловой английский язык. Енютина А.А. - 31 стр.

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    b) Where can the yearly stripping ratio in an operating mine be found?
    c) What is called incremental stripping ratio?
    3. Переведите на английский язык следующие предложения:
    a) Мы можем сократить расходы на выплату ссуды, если как можно
позже начнем выемку пустой породы.
    b) Инвестиции, вложенные в разработку рудника, впоследствии воз-
вращаются в виде доходов.
    c) Правильно ли начинать выемку пустой породы одновременно
с выемкой руды?

                                  TEST № 22

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             Planning and design of open pit mines. Slope angles

     The planning process actually starts at the exploration phase. However,
mine planning must be correlated with all phases of a mining operation. Mine
planning includes ore reserve calculations, determination of rock properties and
structural defects, concentrating characteristics of the ore, marketing considera-
tions, capital expenditures and the cash flow of the venture and its present
value. Elements are closely related and influence each other in such
a way that they must be considered as a whole. If more than one deposit is be-
ing mined in an area, their planning should be integrated. There are three factors
guiding the geometric design of an open pit mine: slope angles, bench height and
berm width, haul road design. Behind the final choice of these criteria lies an
optimization of operational and economic considerations.
     Slope angles. On purely economic grounds, a very steep overall slope is
preferable, the steeper the slope the less waste rock needs to be stripped. On the
other hand, for operational and safety reasons, the slope angle will have to be
limited. There is a definition of several slope angles – overall slope angle, bench
face angle (between the level of berm bottom and its wall) and interrupt slope
angle (between the horizontal level and wall of the ramp) . It can be seen that the
overall slope angle depends not only on the bench face angle but also is affected
by haul road width, bench height and berm width, which are chosen according to
the selected equipment. This in turn is a function of methods used and production