PREPARED BY
NORMAN MANYERUKE
Stages of Mining
Characterization and Monitoring
During Different Phases of Mining
Phases of Mining
1.Prospecting Phase
2.Exploration Phase
3.Advanced Exploration Phase
4.Development Phase
5.Exploitation/Active Mining Phase
6.Closure and Post-Closure Phases
Prospecting
Prospecting the first stage in the
utilization of a mineral deposit, is the
search for ores or other valuable minerals.
Because mineral deposits may be located
either at or below the surface of the earth.
The method of discovery is normally
limited to surface deposits, consists of
visual examination of either the exposure
(outcrop) of the deposit or the loose
fragments (float) that have weathered
away from the outcrop.
Bymeans of aerial photographs, geologic maps, and
structural assessment of an area, the geologist
gathers evidence by direct methods to locate mineral
deposits.
Exploration
Exploration determines as accurately as possible the
size and value of a mineral deposit utilizing
techniques similar to but more refined than those
used in prospecting.
The line of demarcation between prospecting and
exploration is not sharp; in fact a distinction may
not be possible in some cases.
Exploration generally shifts to surface and
subsurface locations using a variety of
measurements to obtain a more positive picture of
the extent and grade of the ore body.
Representative samples may be subjected to
chemical, metallurgical, X ray, spectrographic, or
radiometric evaluation techniques that are meant to
enhance the investigator’s knowledge of the mineral
deposit.
Advanced exploration
Discovery and advanced exploration happens
when something of value is actually found.
At this stage, higher impact activities such as
further ground geophysics, channel
sampling, trenching and diamond drilling,
generally take place.
This work is usually conducted on a mineral
claim or lease. It is at this stage where
permits, leases and licenses are required and
where the project may be referred for
environmental assessment.
Advanced exploration
With promising indications the preliminary study
for rehabilitation should be undertaken on the
site.
Alongwith this the local inhabitants, public,
government agencies should all be notified that
the property is going into advanced exploration.
Majorstripping and trenching, sampling and
assaying, diamond drilling and development of
roads take place.
Deposit evaluation is also done at this stage
testing of mineral value is done. The mine and
the plant design should be started and
completed, preparation for the operating plan
and rehabilitation plan for the site should be
developed.
Development
The work of opening a mineral deposit for
exploitation is performed. With it begins the
actual mining of the deposit now called the
ore.
Access to the deposit must be gained either
(1) by stripping the overburden, which is the
soil and/or rock covering the deposit, to
expose the near-surface ore for mining or
(2) by excavating openings from the surface
to access more deeply buried deposits to
prepare for underground mining. the
provision of a number of requirements
Access roads,power sources, mineral
transportation systems, mineral processing
facilities, waste disposal areas, offices, and other
support facilities, must precede actual mining.
Stripping of the overburden will then proceed if
the minerals are to be mined at the surface
Development for underground mining is
generally more complex and expensive.
Itrequires careful planning and layout of access
openings for efficient mining, safety and
permanence.
The principal openings may be shafts, slopes, or
adits; each must be planned to allow passage of
workers, machinery, ore, waste, air, water and
utilities.
Exploitation
Associated with the actual recovery of
minerals from the earth in quantity. Although
development may continue, the emphasis in
the production stage is on production.
Usually only enough development is done
prior to exploitation to ensure that
production once started, can continue
uninterrupted throughout the life of the
mine.
The mining method selected for exploitation
is determined mainly by the characteristics
of the mineral deposit and the limits imposed
by safety, technology, environmental
concerns and economics
Closure and Post-Closure Phases
The final stage in the operation of most mines is the
process of closing a mine and recontouring, revegetating,
and restoring the water and land values.
The best time to begin the reclamation process of a mine is
before the first excavations are initiated. In other words,
mine planning engineers should plan the mine so that the
reclamation process is considered and the overall cost of
mining plus reclamation is minimized not just the cost of
mining itself.
In planning for the reclamation of any given mine, there
are many concerns that must be addressed. The first of
these is the safety of the mine site, particularly if the area is
open to the general public.
The removal of office buildings, processing facilities,
transportation equipment, utilities, and other surface
structures must generally be accomplished.
