The illustration above shows a drift type of underground mine. A mine
opening is made at the same elevation as the coals seam and mining is conducted
using typically either longwall mining or room and pillar mining with continuous
mining equipment. Coal is transported to the surface by conveyor belts.
This method of mining is used when the coal seam outcrops at the surface,
or when a bench has to be constructed on a mountain side to mine the coal.
Underground mine planning and design has as its goal an integrated mine
systems design, whereby a mineral is extracted and prepared at a desired
market specification and at a minimum unit cost within acceptable social,
legal, and regulatory constraints. A large number of individual engineering
disciplines contribute to the mine planning and design process, such that
it is a multi-disciplinary activity. Given the complexity of the mining
system, planning assures the correct selection and coordinated operation
of all subsystems, while design applies to the traditionally held engineering
design of subsystems. A mining operation should be more correctly viewed
as a system, because of the diversity of technological processes, facilities,
and personal skills required, the large capital invested, the mutual relations
that exist between subsystems, etc. The planning process necessitates a
systems engineering approach suitable for complex design problems.
Planning must account for both environmental protection, beginning as
early as the initial exploration, and for reclamation. It is critical that
planning alleviate or mitigate potential impacts of mining for two key reasons:
(1) the cost of environmental protection is minimized by incorporating it
into the initial design, rather than performing remedial measures to compensate
for design deficiencies, and (2) negative publicity or poor public relations
may have severe economic consequences. From the start of the planning process,
adequate consideration must be given to regulatory affairs. The cost of
compliance may be significantly reduced when taken into account in the design
or planning process, in a proactive manner, rather than being addressed
on an ad hoc basis as problems develop or enforcement actions occur.
From the beginning of the mine design planning stage, data gathering
and permitting, environmental considerations are important, although benefits
from a strictly economic sense may be intangible. From exploration, where
core holes must be sealed and the site reclaimed, through plan development,
the impacts on the environment must be considered. These impacts include
aesthetics, noise, air quality (dust and pollutants), vibration, water discharge
and runoff, subsidence, and process wastes; sources include the underground
and surface mine infrastructure, mineral processing plant, access or haul
roads, remote facilities, etc. If mining will cause quality deterioration
of either surface water or groundwater, remedial and treatment measures
must be developed to meet discharge standards. The mine plan must include
all the technical measures necessary to handle all the environmental problems
from initial data gathering to the mine closure and reclamation of the disturbed
surface area.
Reclamation plans include many of the following concerns: drainage control,
preservation of top soil, segregation of waste material, erosion and sediment
control, solid waste disposal, control of fugitive dust, regrading, and
restoration of waste and mine areas. The plan must also consider the effects
of mine subsidence, vibration (induced by mining, processing, transport,
or subsidence), and impact on surface water and groundwater. These environmental
items often dictate the economics of a planned mining operation and determine
its viability.
The illustration above shows a shaft type of underground mine. A mine
opening is made by sinking a shaft down to the elevation of the coal seam.
Mining is conducted using typically either longwall mining or room and pillar
mining with continuous mining equipment. Coal is transported to the surface
by a skip hoist. This is the most expensive type of underground mine to
build and operate. This method of mining coal is usually utilized when the
coal seam is deep below the surface.
The illustration above shows a slope type of underground mine. A mine
opening is made by tunneling from the surface down to the elevation of the
coal seam. Mining is conducted using typically either longwall mining or
room and pillar mining with continuous mining equipment. Coal is transported
to the surface by conveyor belts. This method of mining coal is usually
utilized when the coal seam is not far from the surface, and the outcrop
of the coal seam is not exposed.
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