Mining_Methods_UnderGround_Mining - Mining and Blasting

Open pit
(mined out)
Producing
stopes
Development
of stopes
Mine inFraSTruCTure
Mined out
and
backfilled
Settling
pond
Exploration
Drilling
places and to power drill rigs, pumps
and other machines. A compressor plant
supplies air to pneumatic rock drills and
other tools, through a network of pipes.
Water reticulation is necessary in the
mine, wherever drilling, blasting and
mucking takes place, for dust suppression
and hole flushing. Both ground
water and flushing water are collected
in drains, which gravitate to settling
dams and a pump station equipped with
high-lift pumps to surface.
Air quality in mine workings must
be maintained at an acceptable health
standard. The mine needs a ventilation
Decline
Abandoned
level
Sublevel
Internal
ramp
Main level
Haulage level
Tailings
Ventilation
shaft
Workshop,
fuelling,
storage
Future reserves?
Basic infrastructure required for a typical underground mine.
Measuring
pocket
Ore
pass
Crusher
Ore
Headframe
Ore
bin
Skip
Cage
Skip
Sump
Production
plant
Water basin
Pump station
Conveyor belt
Skip filling
station
© Atlas Copco Rock Drills AB, 2000
system, to remove smoke from blasting
and exhaust gases from diesel-powered
machines, and to provide fresh air for
the workers. This is normally provided
via downcast fresh-air shafts. Highpressure
fans on surface extract exhaust
air through the upcast shafts. Ventilation
doors control the underground airflow,
passing fresh air through active work
areas. Polluted air is collected in a system
of exhaust airways for channelling
back to the upcast shafts. As most of the
infrastructure is located on the footwall
side of the orebody, the fresh air is
normally channelled via the footwall
towards the hangingwall, from where
the exhaust air is routed to the surface.
Transport infrastructure
Each mining method requires a different
underground infrastructure, such
as access drifts to sublevels, drifts for
longhole drilling, loading drawpoints,
and orepasses. Together, they form an
intricate network of openings, drifts,
ramps, shafts and raises, each with its
designated function.
The shaft is a long-lived installation,
and may be more than 50 years old. The
hoist and cage provide access to the shaft
station, which connects with a main level
along which trains or conveyors may
run. The skip is the most efficient way to
hoist ore from underground to surface.
Materials handling may be by utility
vehicles or locomotive-hauled trains.
The co-ordination of train haulage with
shaft hoisting, from level to level, makes
the logistics of rail transport complex.
Workers in a rail-track mine are required
to wait for cage riding until shift
changes, or scheduled hours, with material
transport only permitted at certain
periods. Ore hoisting takes priority over
manriding and material transport.
The Load Haul Dump (LHD) loader
introduced mines to diesel power and
rubber-tyred equipment in the 1970s.
This was the birth of trackless mining,
a new era in which labour was replaced
by mobile equipment throughout the
mine. Maintenance workshops are now
located underground at convenient
points, usually on main levels between
ramp positions.
The shaft remains the mine’s main
artery, and downward development is by
ramps to allow access for the machines.
On newer mines, as mentioned above, a
decline ramp from surface may facilitate
machine movements and transport
of men and materials, and may also
be used for ore transportation by truck
or conveyor, eliminating the need for
hoisting shafts.
ramps and shafts
Mine development involves rock excavation
of vertical shafts, horizontal drifts,
inclined ramps, steep raises, crusher sta-
tions, explosives magazines, fuel stores,
22 underground mining methods